Doctor of Philosophy In Food Science and Technology

Effect of compositional variation in the milling streams

on rheological behavior of soft wheat dough and its

impact on the end quality of the biscuits.

RAHIL AHMED

Thesis is submitted to fulfill

requirement for the degree of

Doctor of Philosophy

In

Food Science and Technology

Department of Food Science and Technology

University of Karachi

2018

II

III

DEDICATION

THESIS IS DEDICATED

TO MY BELOVED

SUPERVISOR

PROF. DR. RASHIDA ALI

&

MY FAMILY

IV

ACKNOWLEDGMENT

First of all, I am very thankful to Almighty Allah who guided me towards the right path of

learning at every stage of my life that helped in performing my duties in the beneficial

way. I take this opportunity to thank the management of English Biscuit Manufacturers

Pvt. Ltd. (EBM) for all the financial support and laboratory facilities to complete the

present work and to apply my knowledge to achieve the targets that is to serve the

company in most beneficial way. My special thanks are due to Dr. Zeelaf Munir and Ms.

Saadia Naveed for their constant encouragement support. I am indebted to my

supervisor Dr. Rashida Ali for her continuous help and motivation. I am also thankful to

my co supervisor Dr. Asad Saeed for his time to time guidance and support. I would also

like to thank the staff at Centre of Excellence, EBM for their technical assistance.

Last but not the least, I wish to deeply express my gratitude to my parents, wife and

other family members for ignoring my duties and negligence towards my commitments

related to home assignments. I am sure that without their constant moral support this

work wouldn’t has been possible.

V

TABLE OF CONTENT

CERTIFICATE …………………………………….…………………………………………………………..………….…..II

DEDICATION …………………………………….………………………………………………………………….………III

ACKNOWLEDGMENT …….…………………………………………………………………………………………… IV

LIST OF TABLES ………………………………………………………………………………….……………….……… XI

LIST OF FIGURE ……….………………………………………………………………………………………………… XIII

SUMMARY ……………………..……………………………………………………….…………………………….. XVIII

SUMMARY (URDU VERSION) ……………………………………………………………….………………….…XX

LIST OF ABBREVIATIONS …………….………………………………………………………………………….…XXII

LIST OF PUBLISHED RESEARCH PAPERS …………………………………………………………………… XXIV

1. Chapter: Introduction

1.1. Wheat (1-5)

1.1.1. Global wheat production

1.1.2. Wheat production in Pakistan

1.1.3. End use of wheat

1.1.4. Supply chain of wheat

1.1.5. Structure of wheat

1.1.6. Classifications of wheat

1.2. Milling (5-13)

1.2.1. Milling process in brief and its impact on quality of flour

1.2.2. Effect of extraction rate on flour quality

1.2.3. Role of tempering, conditioning or pearling in modification of flour for

biscuit

1.2.4. Pearling

1.2.5. Characteristics of flour suitable for biscuit making

1.2.6. Variation in physicochemical characteristic of flour streams

1.2.7. Parameters to identify quality of flour streams

1.2.8. Relationship of milling with end quality of biscuits

1.3. Wheat flour (13-15)

VI

1.3.1. Composition of flour

1.4. Ingredients other than flour and their functions (15-17)

1.4.1. Sugar and syrup

1.4.2. Milk and role of milk proteins in baking

1.4.3. Egg and role of egg proteins

1.4.4. Fat or Shortening

1.5. Role of additives in biscuit processing (17-19)

1.5.1. Specific enzymes used in modification of biscuit dough

1.5.2. Emulsifiers in biscuit processing

1.5.3. Oxidizing and reducing agents

1.5.4. Hydrocolloids:

1.6. Mixing (19-24)

1.6.1. A process of dough development

1.6.2. Reactions in mixing

1.6.3. Identification of optimal dough

1.6.4. Dough as a predictor of end quality

1.7. Baking (24-27)

1.7.1. Reactions in baking

1.7.2. Role of Ovens in Baking

1.7.3. Baking Zones

2. Chapter: Material & Methods (28-36)

2.1. Materials

2.2. Methods

2.2.1. Physicochemical Analysis

2.2.1.1. Moisture Content

2.2.1.2. Analysis on Kernelyzer

2.2.1.3. Determination of particle size

2.2.2. Farinograph Analysis

2.2.3. Micro Visco-Amylo-Graph Analysis

VII

2.2.4. Glutomatic Analysis

2.2.5. Determination of Damaged Starch Content by SDmatic

2.2.6. Scanning Electron Microscopy (SEM)

2.2.7. Solvent retention capacity

2.2.8. AWRC profiles of flours

2.2.9. Statistical Analysis

2.2.10. Evaluation of biscuit quality

3. Chapter: Wheat Milling and its Industrial Application

3.1. Study of milling streams used in production of commercial flours to be utilized in

biscuit making industry (37-91)

3.1.1. Foreword of the study

3.1.2. Material & Method

3.1.3. Result and discussion

3.1.3.1. Physicochemical Analysis of Milling Streams

3.1.3.2. Study of the Dough Rheology– Farinograph Analysis

3.1.3.3. Pasting Behavior of Dough – MVAG

3.1.3.4. Solvent Retention Capacity of Flour Streams – SRC

3.1.4. Conclusion

3.2. Comparative analysis of physiochemical and dough rheological properties of

break and reduction streams and its impact on the quality of cookie. (92-99)


3.2.2. Material and Method

3.2.3. Result and Discussion

3.2.3.1. Comparative analysis of physicochemical parameters in break and

reduction streams

3.2.3.2. SRC analysis

3.2.3.3. Farinograph parameters:

3.2.3.4. Micro Visco-Amylo-Graph

3.2.3.5. Glutomatic Parameters

VIII

3.2.3.6. End quality evaluation

3.2.4. Conclusion

4. Chapter: Solution of Industrial Problem

4.1. To study wheat available in Pakistan suitable for soft product. Identification of

optimum level of damaged starch along with other physicochemical properties

for the soft dough. (100-114)




4.1.3.1. Physical Analysis of wheat

4.1.3.2. Instrumental Analysis of wheat

4.1.3.3. Physicochemical analysis of flour

4.1.3.4. Farinograph

4.1.3.5. Observation of line behavior of flour on production lines

4.1.4. Conclusion

4.2. Dough stickiness & mitigation in product (115-121)


4.2.2. Problems Due to Stickiness

4.2.3. Possible factor affecting stickiness of the dough

4.2.4. Approach and mechanism to minimize stickiness from sheeted product.

4.2.5. Flour analysis parameters for sheeted products

4.2.6. Conclusion

5. Chapter: Flour, quality assessment and its treatment

5.1. Wheat flour characteristics of different countries (122-128)




5.1.3.1. Physicochemical Characteristics

5.1.3.2. Farinograph parameters

IX

5.1.3.3. Damaged Starch and Particle size distribution

5.1.3.4. Glutomatic Proteins of flour from different wheat sources

5.1.3.5. Damaged Starch affecting Water absorption of Flour

5.1.3.6. Particle size affecting Damaged Starch Content

5.1.4. Conclusion

5.2. Prediction of damaged starch by assessing some physicochemical quality of

wheat flour (129-144)

5.2.1. Foreword of the Study



5.2.3.1. Damaged starch versus physicochemical properties of flour

5.2.3.2. Relationship of DS with SRC and AWRC values

5.2.3.3. Farinographic parameters versus damaged starch

5.2.3.4. Damaged starch versus pasting curve of micro Visco-Amylo-Graph

5.2.3.5. Relationship of Proteins from Glutomatic and DS

5.2.4. Conclusions

5.3. Effect of commercial enzymes (proteases & carbohydrases) on dough rheology

and end quality of Cookie (145-152)





5.3.3.2. Enzyme affecting Farinograph Properties of flour

5.3.3.3. Enzymes affecting Micro Visco-Amylo-Graph Properties

5.3.3.4. Enzymes affecting Glutomatic Properties

5.3.3.5. Dimensional Properties of the end product

5.3.4. Conclusion

X

6. Chapter: Nutraceutical product

6.1. Legume protein enrich biscuits and its impact on rheological properties of

dough/the end quality (153-159)




6.1.3.1. Physicochemical properties and SRC analysis

6.1.3.2. Rheological properties

6.1.3.3. Farinograph analysis

6.1.3.4. Micro Visco-Amylo-graph

6.1.3.5. Glutomatic protein profile

6.1.3.6. Dimensional and sensory analysis of biscuits

6.1.4. Conclusion

6.2. Black gram flour in cookie dough as a substitute of egg (160-167)




6.2.3.1. Physico-chemical quality

6.2.3.2. Farinograph Attributes

6.2.3.3. MVAG Analysis

6.2.3.4. Microstructure of Biscuit Dough

6.2.3.5. Dimensional/textural quality

6.2.3.6. Sensory Analysis

6.2.4. Conclusion

7. Reference (168-176)

XI

List of Tables

Table 1: Area, production and yield of wheat

Table 2: Combination of zone used for commercially baked biscuits in Hybrid ovens

Table 3: Streams names, types and description

Table 4: Milling streams type and details

Table 5: Recipe of cookie to evaluate the effect of different milling streams

Table 6: End Quality Analysis

Table 7: Month wise wheat source utilized by flour suppliers.

Table 8: Instrumental analysis of wheat (Source wise).

Table 9: Physical analysis of wheat (Source wise).

Table 10: Moisture, ash and gluten analysis

Table 11: Particle size and damaged starch analysis

Table 12: Farinographic analysis of flour samples

Table 13: Line observation of flour. (Numbers mentioned in bracket after source name

indicating rating of line behavior for the month)

Table 14: Flour parameters suitable for sheeted product

Table 15: Temperature ranges suitable for sheeted product

Table 16: Farinograph parameter suitable for sheeted product

Table 17. Physiochemical properties of different wheat sources

Table 18: Farinograph parameters of flour from different wheat sources

Table 19: Glutomatic properties of flour from different wheat sources

Table 20. Damaged starch and particle Size analysis of flour

Table 21: Physicochemical analysis of different flour samples

Table 22: SRC and AWRC of wheat flour samples

Table 23: Farinograph parameters in various flour

Table 24. Micro Visco-Amylo-Graph parameters of various flour

Table 25: Glutomatic proteins and DS of various flour

Table 26: DS vs NG-WA

XII

Table 27: Recipe of biscuit for enzyme study

Table 28: Physicochemical parameters

Table 29: Enzyme affecting farinograph Properties

Table 30: Enzyme affecting Micro Visco-Amylo-Graph properties

Table 31: enzyme affecting glutomatic properties

Table 32: Recipe of biscuits with legume

Table 33: Physicochemical and SRC analysis of substituted flour

Table 34: Farinograph and Micro Visco-Amylo-Graph, glutomatic profile of substituted

flour

Table 35: Dimensional properties of biscuits

Table 36: Correlation of different parameters with % substitution of MBF

Table 37: Recipe of BGF biscuit

Table 38. Physico-chemical analysis of BGF

Table 39. Farinograph properties of BGF added dough

Table 40. BG flour affecting Micro Visco-Amylo-Graph properties

Table 41. End product quality

Table 42. Eating quality of BGF added biscuit.

XIII

List of Figures

Figure 1: Composition of wheat

Figure 2: A brief diagram of milling

Figure 3: Flow chart of milling streams for flour collection

Figure 4: Variation in moisture (%) in flour from break rolls streams.

Figure 5: Variation in moisture (%) in flour from semolina streams.

Figure 6: Variation in moisture (%) in flour from semolina overtail streams

Figure 7: Variation in moisture (%) in flour from middling streams

Figure 8: Variation in protein (%) in flour from break rolls streams

Figure 9: Variation in protein (%) in flour from semolina streams

Figure 10: Variation in Protein (%) in flour from semolina overtail streams

Figure 11: Distribution of protein (%) in flour from middling streams.

Figure 12: Variation in ash (%) in flour from break rolls streams

Figure 13: Variation in Ash (%) in flour from semolina streams

Figure 14: Ash (%) in Flour Streams from semolina overtail streams

Figure 15: Variation in ash (%) in flour from middling streams

Figure 16: Variation in gluten Index (%) in flour from break rolls streams

Figure 17: Variation in Gluten Index (%) in flour from semolina streams

Figure 18: Variation in Gluten Index (%) in flour from semolina overtail streams.

Figure 19: Variation in Gluten Index (%) in flour from middling streams

Figure 20: Variation in Dry Gluten (%) in flour from break rolls streams

Figure 21: Variation in Dry Gluten (%) in flour from semolina streams

Figure 22: Variation in dry Gluten (%) in flour from semolina overtail streams.

Figure 23: Variation in dry Gluten (%) in flour from middling streams.

Figure 24: Variation Wet Gluten (%) in flour streams from 18.8 to 28.78%.

Figure 25: Showing minor variation in wet gluten (%) in flour streams from 20.70 to 26.1

Figure 26: Variation in Wet Gluten (%) in flour streams from 25.75 to 29.23

XIV

Figure 27: Wet Gluten (%) in flour streams from middling

Figure 28: Showing increase in % retention at 160 µm sieve of flour streams from break

rolls

Figure 29: % Retention at 125 µm sieve of flour streams from break rolls

Figure 30: % through from 125 µm sieve of flour streams from break rolls

Figure 31: % Retention at 160 µm sieve of flour Streams from semolina showing retention

0.1 to 9.1%

Figure 32: % of flour streams retained at 125 µm sieve from 5.0 to 72.8% in semolina

passages

Figure 33: % of flour streams from semolina from 125 µm sieve.

Figure 34: % of Flour Streams from 0.1 to 4 retained at 160 µm sieve in semolina overtail

passages

Figure 35: % Retention at 125 µm sieve of flour streams from semolina overtail

Figure 36 : % through from 125 µm sieve of flour streams from semolina overtail

Figure 37: % Retention at 160 µm sieve of flour streams from middling


Figure 39: % through from 125 µm sieve of flour streams from middling

Figure 40: FQN in flour from break rolls streams

Figure 41: FQN in flour from semolina streams

Figure 42: FQN in flour rom semolina overtail streams

Figure 43: FQN in flour from middling streams

Figure 44: Water absorption % in flour from break rolls streams

Figure 45: Water absorption % in flour from semolina streams

Figure 46: Water absorption % in flour from semolina overtail streams

Figure 47: Water absorption % in flour from middling streams

Figure 48: DDT (min) in flour from break rolls streams

Figure 49: DDT (min) in flour from semolina streams

Figure 50: DDT (min) in flour from semolina overtail streams

Figure 51: DDT (min) in flour from middling streams

XV

Figure 52: DST (min) in flour from break streams

Figure 53: DST (min) in flour from semolina streams

Figure 54: DST (min) in flour from semolina overtail streams

Figure 55: DST (min) in flour from middling streams

Figure 56: DoS (FU) in flour from break streams

Figure 57: DoS (FU) in flour from semolina streams

Figure 58: DoS (FU) in Flour from semolina overtail streams

Figure 59: DoS (FU) in flour from middling streams

Figure 60: Max. Viscosity (BU) in flour from break streams

Figure 61: Max. Viscosity (BU) in flour from semolina streams

Figure 62: Max. Viscosity (BU) in flour from semolina overtail streams

Figure 63: Max. Viscosity (BU) in flour from middling streams

Figure 64: BD Viscosity (BU) in flour from break streams

Figure 65: BD Viscosity (BU) in flour from semolina streams

Figure 66: BD Viscosity (BU) in flour from semolina overtail streams

Figure 67: BD Viscosity (BU) in flour from middling streams

Figure 68: SB Viscosity (BU) in flour from break streams

Figure 69: SB Viscosity (BU) in flour from semolina streams

Figure 70: SB Viscosity (BU) in flour from semolina overtail streams

Figure 71: SB Viscosity (BU) in flour from middling streams

Figure 72: SC-SRC flour from break streams

Figure 73: SC-SRC in flour from semolina streams

Figure 74: SC-SRC in flour from semolina overtail streams

Figure 75: SC-SRC in flour from middling streams

Figure 76: W-SRC flour from break streams

Figure 77: W-SRC in flour from semolina streams

Figure 78: W-SRC in flour from semolina overtail streams

Figure 79: W-SRC in 6 flour from middling streams

XVI

Figure 80: Su-SRC flour from break streams

Figure 81: Su-SRC in flour from semolina streams

Figure 82: Su-SRC in flour from semolina overtail streams

Figure 83: Su-SRC in flour from middling streams

Figure 84: LA-SRC (%) in flour from break streams

Figure 85: LA-SRC in flour from semolina streams

Figure 86: LA-SRC in flour from semolina overtail streams

Figure 87: LA-SRC in flour from middling streams

Figure 88: Moisture, protein, particle size, bottom and damaged starch content of break

and reduction passages.

Figure 89: Variation in SRCs in two types of milling streams

Figure 90: Farinograph analysis of milling streams

Figure 91: Milling streams on Visco-amylo-graph parameters

Figure 92: Milling streams on glutomatic parameters

Figure 93: Instrumental and physical analysis of wheat (Source wise)

Figure 94: Moisture, ash and gluten analysis

Figure 95: Particle size analysis

Figure 96: Farinographic analysis of flour samples

Figure 97: Damaged starch

Figure 98: Trend of damaged Starch supplier wise (Numeric values on X axis shows the

month i.e. 1 Jul)

Figure 99: Flow chart of work plan to rectify the issue

Figure 100 . Root cause Analysis/4M’s techniques to identify the root cause

Figure 101: Crumb generation

Figure 102: Effect of particle size on damaged starch content

Figure 103: Effect of particle size on damaged starch content of flour

Figure 104: Damaged starch vs total protein contents

Figure 105: DS vs AWRC

Figure 106: DS vs SC-SRC

XVII

Figure 107: DS vs W-SRC

Fig. 108: DS vs LA-SRC

Figure 109: DS vs Su-SRC

Figure 110: DS vs WA.

Figure 111: DS Vs dough quality parameters DDT.

Figure 112: DS Vs Beginning of Gelatinization temperature

Figure 113: DS Vs Trough Viscosity

Figure 114: DS Vs Final Viscosity

Figure 115: DS Vs Peak Viscosity

Figure 116: Damaged vs passed gluten

Figure 117: Damaged starch vs retained gluten

Figure 118: Damaged starch vs gluten index

Figure 119: DS vs NG-WA

Figure 120: Proteases and amylases on cookies factor

Figure 121: Sensory score of biscuit made with control and substituted flour

Figure 122: (a) control (b) 2 gm BGF added dough (c) 4 gm BGF added dough and (d) 6 gm

BGF added dough respectively.

XVIII

Summary (English)

The present study was taken up with certain defined aims and objectives to promote

research that is directly applicable to the industry and involves deep learning at higher

education level. The objectives included as study of milling streams for selection of

desired flour for biscuit making, solution of problems related to dough rheology, role of

damaged starch in assessment of flour quality, use of commercial enzymes in dough

modification and improvements in the end quality of biscuits, nutraceutical biscuits

(including egg and fat replacements). The research applied at various stages of processing

is briefly described here,

Milling for selection of desired flour: Optimal or desired composite flour was obtained

after a close coordination between the miller and baking industry (EBM). Certain

physicochemical tests were identified to blend the streams for getting the desired

composite flour.

Solution of problems: Number of problems faced in processing were solved through

research such as conversion of hard flour to soft by using enzymes (proteases and

carbohydrases) as a dough modifier. The research revealed that enzymes may be

inhibited by certain recipe ingredients and selection of enzymes is a highly technical.

Dough Stickiness: The problem of stickiness of dough was solved by using previously

prepared dough, chilled water to adjust solid fat index (SFI) and addition of little fat at

the later stage of mixing.

Role of damaged starch (DS): The studies related to the effect of DS in biscuit processing

are missing. We studied the estimation of DS in flour through physicochemical tests (SRC,

AWRC) and related it to Farinograph and Micro Visco-Amylo-Graph parameters.

Nutraceutical biscuits: Biscuits with enhanced nutritional status were prepared, as

legumes are enriched in protein. Problems in dough rheology due to addition of legume

proteins were adjusted by considering physicochemical changes as observed by

Farinograph, Micro Visco-Amylo-Graph and Glutomatic.

XIX

Egg replacement: Black gram flour was also successfully used to replace egg in biscuit.

Egg enrichment often is not desired by customers because of the presence of saturated

fat and cholesterol in eggs.

Fat replacement: Black gram was found as a good substitute for fat in biscuit recipe.

End quality improvement: The study also involved improvement in end quality of biscuit,

for example it was observed that DS in low percentage is desired in most of the recipe.

High DS increases water absorption in dough that causes size reduction and heavy weigh.

Cost reduction: The industries usually do not support the use of the highly sophisticated

costly instruments such as Farinograph, Micro Visco-Amylo-Graph etc. the present study

suggested the use of simple tests i.e. SRC, AWRC as the alternatives.

Application of finding of milling study enabled industry to save the losses because of

wastages, low productivity due to heavy weight problem in cookies.

XX

Summary (Urdu)

XXI

XXII

List of Abbreviation

PSQCA Pakistan Standard Quality Control Authority

EBM English Biscuit Manufacturers Pvt. Ltd.

COE Centre of Excellence

SEM Scanning Electron Microscopy

MVAG Micro Visco-Amylo-Graph

Gm Gram

Kg Kilogram

Hr Hour

Min Minute

DS Damaged Starch

DDT Dough Development Time

DST Dough Stability Time

WA Water Absorption

DoS Degree of Softening

HMW High Molecular Weigh

LMW Low Molecular Weight

GI Gluten Index

PG Passed Gluten

RG Retained Gluten

DG Dry Gluten

PV Peak Viscosity

MV Maximum Viscosity

BD Breakdown

SB Setback

TV Trough Viscosity

FU Farinograph Unit

BU Brabender Unit

UCD Unite Chopin Dubois

SRC Solvent Retention Capacity

XXIII

AWRC Alkaline Water Retention Capacity

SC-SRC Sodium Carbonate Solvent Retention Capacity

Su-SRC Sucrose Solvent Retention Capacity

W-SRC Water Solvent Retention Capacity

LA-SRC Lactic Acid Solvent Retention Capacity

MBF Mash Bean Flour

BGF Black Gram Flour

PPO Polyphenol Oxidase

ER Extraction Rate

FN Falling Number

XXIV

List of Published Research Paper

Rahil Ahmed, Rashida Ali, Syed Asad Saeed, Syed Muhammed Ghufran Saeed and Lubna

Mobin. (2017). Impact of distinct compositional variations in flours of various milled

streams on dough behavior and end quality of baked products. Pak. J. Bot., 49(SI): 383-

387.

Rahil Ahmed, Rashida Ali, Muhammad Shakeel Khan, Madiha Moin, Saira Imtiaz Kazmi

and Syed Asad Saeed. (2015). Comparative Study on the Physicochemical and

Rheological Parameters of Soft Wheat Flour Obtained from Three Countries. American

Journal of Food Science and Nutrition Research. 2(3): 89-93.

Rahil Ahmed, Rashida Ali, Muhammad Shakeel Khan, Syed Asad Sayeed, Jahangir Saeed

and Fariha Yousufi. (2015). Effect of Proteases & Carbohydrases on dough Rheology and

End Quality of Cookie. American Journal of Food Science and Nutrition Research, 2(2):

62-66.

Muhammad Shakeel Khan, Rahil Ahmed, Rashida Ali and Syed Asad Sayeed. (2015).

Relationship of Sodium Carbonate SRC with Some Physicochemical, Rheological and

Gelatinization Properties of Flour and its Impact on End Quality of Biscuit, International

Journal of Scientific and Research Publications, 5(8), 1-8.

Rashida Ali, Muhammad Shakeel Khan, Syed Asad Saeed, Rahil Ahmed, Syed Muhammed

Ghufran Saeed and Lubna Mobin. (2014). Relationship of damaged starch with some

physicochemical parameters in assessment of wheat flour quality. Pak. J. Bot., 46(6):

2217-2225.

Rashida Ali, Syed Muhammad Ghufran Saeed, Syed Arsalan Ali, Syed Asad Sayed, Rahil

Ahmed and Lubna Mobin. (2018). Effect of black gram flour as egg replacer on

microstructure of biscuit dough and its impact on edible qualities. Journal of Food

Measurement and Characterization. https://doi.org/10.1007/s11694-018-9779-3.

https://doi.org/10.1007/s11694-018-9779-3

XXV

Lubna Mobin, Syed Asad Saeed, Rashida Ali, Syed Muhammed Ghufran Saeed and Rahil

Ahmed. (2017). Antibacterial, antioxidant and phenolics compound analysis of Abrus

Precatorius seed coat extract and its different reactions. Pak. J. Bot., 49(6): 2499-2506.

Lubna Mobin, Syed Asad Saeed, Rashida Ali, Syed Muhammed Ghufran Saeed and Rahil

Ahmed (2017). Antibacterial and antifungal activities of the polyphenolic fractions

isolated from the seed coat of Abrus precatorius and Caesalpinia crista. Natural Product

Research. DOI:10.1080/14786419.2017.1378217.

1

1. CHAPTER: INTRODUCTION

1.1. Wheat

Wheat (Triticum aestivum L.) is a staple food in Pakistan like in most part of the world

and it is a widely grown crop in most of the countries. Wheat produced in Pakistan is

consumed mostly in making chapattis, rotis and naan (Anjum and walker, 1991). Wheat

is primary diet and is the cheapest source of proteins. Pakistan has been producing wheat

enough to fulfill the local demand. Recently Pakistan is also exporting surplus produced

wheat from last two to three years.

1.1.1. Global wheat production

Global wheat production has decreased by 15 million tons this year (2016-17) from last

year production which is still second highest world production (738 million tons). A

decrease of 29 million tons is expected in major exporting countries. Argentina and EU

will achieve higher production whereas Australia, Canada, Kazakhstan, Russia, Ukraine

and United State will produce less wheat. In EU, production is expected to increase by

4% from the last year whereas Argentina will produce more wheat due to expansion in

the growing area.

Forecast production of wheat in Russia shows decline from last year however, it is the

second highest yield. About 7% decline is expected in Ukraine. US will produce wheat in

less quantity than the last year. China and India will produce high quantity of wheat.

Consumption of wheat as animal feed is expected to reduce worldwide whereas wheat

as human food will be on rise in the many parts of the word. High consumption of wheat

in south and South East Asia is expected due to population growth, urbanization and

because of rising income through agriculture.

(Source: Foreign Agricultural Service / USDA)

2

1.1.2. Wheat production in Pakistan

Wheat being main the agricultural crop in Pakistan, is grown around 9 million hectares

area which is nearly country’s 40% of the total land (cultivated) during the Rabi season.

Wheat contributes for 9.9% in the value added in agricultural products that represented

2.0% of GDP of Pakistan during 2015-16. (USDA Agricultural service)

Ministry of Finance, Pakistan has shown an increase of 0.6%, 9260 thousand hectares

(2015-16) from last year’s area of production 9204 (2014-15). Above 25482 million tons

wheat was produced, with 1.6% increase in comparison to the production last year

(25086 million tons). The increase in production per unit area as shown in table 1 was

due to enough time and moisture available specifically in Barany track which maintained

the germinated progress.

Table 1: Area, Production and Yield of Wheat

Year

Area Production Yield

(000

Hectares)

%

Change (000 Ton)

%

Change

(Kg/

Hec.)

%

Change

2011-12 8650 - 23473 - 2714 -

2012-13 8660 0.1 24211 3.1 2796 3

2013-14 9199 6.2 25979 7.3 2824 1

2014-15 9204 0.1 25086 -3.4 2726 -3.5

2015-16P 9260 0.6 25482 1.6 2752 0.9

P: Provisional (July-March)

Source: Pakistan Bureau of Statistics

1.1.3. End use of wheat.

Wheat is milled to produce flour. Flour is used for making chapatti (flat bread), naan,

bread, biscuit, cake, pasta, pizza etc. for commercial purpose. In Pakistan two methods

of milling are mostly practiced (1) Roller milling (Large scale) (2) Stone grinding (Chaki) at

3

small scale. Chakki milling is very popular at domestic level in which wheat is completely

ground into flour by using stone grinding technique.

Roller milling is used to make flour by separating bran from endosperm and germ.

Different quality of flours are achieved during milling. Pure white portion of endosperm

is separated as Maida and is sold for commercial purpose (Bakery industries). Bran is used

for animal feed whereas mixture (Aatta) of endosperm with high amount of bran is used

at domestic level for making Chapati.

1.1.4. Supply chain of wheat

Wheat in Pakistan is a Government controlled commodity. Availability of specific quality

of wheat for consistency is always challenging for baking /milling industries in Pakistan.

There is no system available at government level to guide farmers at growing stage.

Wheat is ground at the milling unit in extremely uncontrolled manner, despite of the fact

that actual requirements for the end use quality are already reviewed.

Grading of wheat at the purchasing stage is also unavailable, Govt. decides prices of

wheat without considering quality / grades. Millers always face difficulties in producing

good quality flour as the sub-standards wheat quality is also grown without control.

1.1.5. Structure of wheat

Although wheat is a grain but is included in the grass family in botanical way of

classification. It belongs to the class of caryopsis where fruit wall (pericarp) and seed coat

are enacted, resulting in the separation of fruit from seed.

Wheat differs in shapes, may be oval or spherical, long or of flattened shape. The length

of wheat kernel varies from 5-9 mm and a single grain weighs 35 to 50 mg. The grain

contains 2-3% germ, 13-17% bran and 80-85% endosperm (on dry basis). (Belderoket et

al, 2000; Posner, 2000).

Several layers together compose the bran, the outer most layer that protects the main

part of the grain and is rich in B vitamins, minerals, phytochemicals and fibers.

4

Source: http://www.nabim.org.uk/nabim

Figure 1: Composition of wheat

1.1.6. Classifications of wheat:

In United States wheat is classified as described below,

Durum Wheat

The light-colored kernel which is hard and translucent, is recommended to be used to

make semolina flour for variety of bakery products i.e. pasta, spaghetti etc. Kernels are

rich in gluten proteins.

Red Spring wheat (hard)

The variety (kernel) is hard, slightly brownish, and rich in protein content. Specific wheat

is recommended for bread and other products with strong gluten network (Pasta).

Red Winter Wheat (hard)

It is also hard in structure and contains dark yellow protein. It is recommend to be used

in bread and pasta. It is also used in combination with other low gluten wheat to increase

the gluten level in composite flour.

https://en.wikipedia.org/wiki/Wheat_production_in_the_United_States

https://en.wikipedia.org/wiki/Durum

https://en.wikipedia.org/wiki/Semolina

https://en.wikipedia.org/wiki/Pasta

5

Soft Red (winter)

It is soft and low in gluten content. Recommend to be used in Cake, cookies and biscuits

etc.

Hard White Wheat

Its crop is planted in very dried and high temperature field. It is hard in nature and light

in colored.

Soft White Wheat

It is soft in nature and also light in colored. It is low in protein and grown in temperate

moist areas.

The classification of wheat in Pakistan is not well defined, only hard, soft or seasonal

varieties of wheat are mentioned in the standards/specifications/literature.

1.2. Milling

1.2.1. Milling process in brief and its impact on quality of flour

Milling is a process of gradual grinding and fractionation to convert grain into flour. The

prime objective of the milling is to separate endosperm from bran and germ first,

followed by further grinding the endosperm into a large number of fractions called

streams (Campbell, 2007). Each stream differs in its composition, particle size and

distribution of flour particle according to its size. The performance of milling is greatly

influenced by the grain hardness or the grain class. The streams are combined to produce

the composite flour indicating that various category of flours may be obtained with

specific characteristics by combining or blending the different streams. This shows that

quality of the resulting flour depends on selection of the specific streams which differs

widely in their composition and thus in their functionality to produce a particular bakery

product (Souza et al, 2011). The streams selected for bread flour will be different than

the streams blended for biscuit. Milling is therefore a highly technical process to provide

6

the options to bakers for getting desired flour to process their target product (Ahmed et

al, 2017). Major steps in milling are given in fig. 2.

Figure 2: A brief diagram of milling

1.2.2. Effect of extraction rate on flour quality

The quality of flour depends on the extraction rate (ER) defined as ratio of flour with rest

part of the wheat (Aprodu et al, 2010). The pure white flour is obtained with lower

extraction rate i.e. ER less than 75% as the endosperm extraction rates increases to reach

the theoretically maximum ER of 81-84%, the flour gets contaminated with bran and the

color is changed to yellowish brown. The flour consisting all the bran is called whole meal

flour with 100% nutritive value and high amount of fibers (Sudha et al, 2007). The

nutritional quality of wheat flour decreaseS with decrease in ER because of inclusion of

bran which is rich in dietary fibers and many bioactive components such as vitamin B

group, minerals, tryptophan, carotenoids and lignin etc. (Symons et al, 1996). Milling

process is thus a determining factor in providing a healthy flour to the consumers.

CLEANING

WASHING

BREAK

FLOUR

REDUCTION

SOAKING

WATER

EXTRINIOUS MATTERS COME OUT

DUST IS WASHED WITH WATER

WHEAT KERNAL ABSORB WATER,

CUASING KERNAL TO SOFTEN AND

OPEN THE WHEAT KERNAL AND

SEPARATE BRAN WITH ENDOSPERM

ENDOSPERM IS PASSED THROUG

MULTIPLE SET OF ROLLS, PURIFIERS

AND SIFTERS

7

The compositional changes in flour take place as the extraction rate increases and tail

streams are obtained. Ash, protein, damaged starch increase with flour towards high ER

(Ahmed et al, 2017). It is also reported that fiber, protein, wet gluten increase however

falling number, sedimentation values and moisture decrease in soft wheat (Moiraghi et

al, 2011). The water absorption as determined by Farinograph also increases with the

increase of damaged starch content. High protein also leads to increase in water

absorption of flour. Milling process demands skilled and qualified manpower to achieve

the quality of flour and to supply the desired flour to bakers according to the product

they are handling.

1.2.3. Role of tempering, conditioning or pearling in modification of flour for biscuit

Conditioning is the process of spraying water on kernels (moistening) before milling and

if the temperature and additives are also taken into consideration, the process may be

referred as tempering. The objective of tempering/conditioning is to toughen the

pericarp (bran) and to mellow (soften) endosperm in order to separate the two easily

during milling. There are at least four different parameters which affect the milling

process and the end quality of flour. The initial moisture or intrinsic moisture of the

kernel, tempering moisture, time for moisturizing and temperature of tempering.

(Rehman et al, 2006)

The rate of water penetration into the kernel or the diffusion rate is directly related to a

number of factors particularity compositions of endosperm, the amount of hydrophilic

polymers such as protein, starch, damage starch, non-starch polysaccharides etc. The

protein content and its quality, temperature, and nature of additives used also influence

water absorption. Usually around 16.0% moisture in wheat kernel provides better result

during milling. The quality of flour during milling is most commonly evaluated by ash

content which is an indicator of bran inclusion gradually in flour. However during recent

decades polyphenol oxidase (PPO) is taken as a reliable measure of bran contamination.

PPO is solely present in bran and therefore extent of PPO activity measures bran quality.

8

The quality of flour is greatly affected by using additives in the process of conditioning

such as the oxidizing/reducing agents, enzymes and salts. The use of some enzymes as

xylanase, and amylases during tempering has improved the functional rheological

properties of biscuit dough because enzymes hydrolyzed the major biopolymers

(Pentosans) of bran i.e. arabinoxylans that increases water absorption in mixing and

reduces the dimensional properties of biscuit.

Tempering/conditioning improves and alters the quality of wheat grain milling process

that is the process of scissoring precisions to get desired ratio of bran-germ-endosperm

at the end (Glenn and Johnstan, 1992). The research has shown that

tempering/conditioning is an ideal tool in the hands of miller to modify the quality of

flour accordingly.

1.2.4. Pearling

Tempering/conditioning process as mentioned earlier change the quality of flour,

enzyme treatment are specifically active in controlling the dough behavior or as well as

the yield of flour. The cocktail of the cell wall degrading enzymes consisting cellulase,

xylanase and peclinase are added in tempering water to increase the flour recovery in

break streams as compared to reduction streams in a roller mill (Yoo et al, 2009).

Regarding the end quality of biscuits, the diameter is strongly negatively related to biscuit

thickness (r2= -0.986, p<0.001), particle size, damage starch protein and SRC-parameters.

All the above characteristics are highly dependent on the milling process.

1.2.5. Characteristics of flour suitable for biscuit making

The flour ideal for biscuit production has been identified by variety of indicative tests, the

following properties may be considered in evaluation of optimal flour.

- Soft flour is the most suitable, soft wheat kernel should be selected for getting best

performance of the flour. Soft flour is actually low in protein, ash, damaged starch

etc.

- Low protein content (7-10%) provides better rheological behavior of the biscuit

dough. Bradford dye binding method for quantification of protein is still used being

9

simple (Iqbal et al, 2015). However sedimentation value is a good indicator to

evaluate protein quality and specially glutenin content. Low sedimentation value are

more suitable to select flour quality (Ramrez-Suarez, 2005).

- Low ash content provide better result in dough development during mixing. Although

ash indicates the mineral contents of the flour, however minerals are mostly located

in bran so ash indirectly is related to bran quantity or the ER.

- Damaged starch. Flour low in damaged starch is selected by the bakers in biscuit

factory. Damaged starch is high in hard flour because hard wheat kernel need more

pressure to break the grain that damages starch granules. Damage starch in the range

of below 26 UCD is suitable for biscuit making, however the values changes from

recipe to recipe.

- Moisture content plays an important role in determining the quality of flour. Low

intrinsic moisture and low tempering moisture is suitable for biscuit making because

excess water is able to hydrate sugar particles easily giving sticky dough, and reduced

size of biscuits.

- Pentosans are biopolymers with monomers of 5 carbon atoms which vary largely in

nature. In wheat flour arbinoxylan is located in bran largely. Pentosans are generally

located in the cell wall and indicate bran percentage in flour. Less quality of pentosan

is needed for biscuit processing.

- Water absorption plays key role in the hydration process of all the ingredients in

biscuit recipe. Low water absorption is needed for biscuit rheology because it restricts

protein network formation that is pre-requisite in biscuit dough formation.

It is well illustrated that significant close relationship exists between flour quality and

many biochemical factors and numerous biochemical components contributes to quality

variance in flour and one should not rely on a single test for flour quality selection.

1.2.6. Variation in physicochemical characteristic of flour streams

Soft wheat kernels with low protein and high intrinsic moisture harvested in winter are

preferred for biscuit manufacturing because of their suitability for easy milling and

producing less damaged starch. The distinct compositional variation in flour has been

10

noticed both at the break and reduction stages. The lower value of hardness, stickiness

and cohesiveness of the dough reduce cutting strength. Sprouted kernels decrease the

hardness of the dough but increase end quality or acceptability of biscuits (Agrah-ar-

Murekgkar, 2015; Moreira, 2015). The pilot milling analysis of soft winter wheat shows

that ash, protein and water extractable solids including water extractable arabinoxylans

increase exponentially in the reduction streams. (Souza et al, 2011). Flour milling also

alters microstructure of the intact endosperm tissues which are densely packed and give

the compact structure that gets disintegrated during milling forming aggregates of starch

granules taking their position in protein matrix. Deformation of starch granule (type S)

increases with harshness in reduction milling (distance between roller is reduced) and

damage starch (DS) increases (Gangadarappa et al, 2008). DS usually present in the range

from 5.14% to 14.79% in different streams, is strongly negatively correlated with biscuit

spread ratio (Bareera et al, 2007). In the straight grade flour with 72% flour recovery (ER),

the tail end streams have high percentage of damage starch and pentosans forming

weaker dough.

Recently Liu and coworker (2015) have shown that milling governs the sensory qualities

of bakery products. Moreover the characteristics of the viscoelastic dough from only flour

and water may complement the physicochemical parameters in predicting the

consistency of the dough for the laminated biscuit recipe (Fustier et al, 2009). The

Rheological properties of flour change in both types of flour i.e. the break flour streams

and the reduction flour streams, however changes are more pronounced in the break

streams. The total protein contents, falling number, sedimentation value and oil content

of the flour increase with an increase of break streams, while the color intensity of the

flour decreases. Interestingly these changes were not so visible in the reduction flour

streams (Prabhasankera et al, 2000). The fatty acid composition of oil changes

accordingly to streams, palmatic acid and linoleic acid contents were major in saturated

and unsaturated acids respectively. Protein content used as the predicator of baking

performance and end quality is related to variety of rheological properties of dough, and

changes significantly in various streams (Koppel and Ingver, 2010). The milling and baking

performances of the flour are very closely correlated to each other and milling process

11

including pre-milling (as conditioning or tempering) may be modified to produce the flour

of desired baking performance. Predominant correlation was observed between water

absorption and yield of semolina as bran gets easily removed on wetting (Huskova et al,

2006). Mill streams produce flour of high diversity and complexity. The components as

ash, wet gluten, phytic acid, damaged starch and amylograph peak viscosity change

affecting the fermentative activity of baker’s yeast (saccharomyces cerevisiae),

consequently every mill streams will behave differently during baking (Katarina eta al,

2008). The resting and proofing times will be dependent on the type of streams blended

with variable fermentative ability. The values of damage starch, falling number of flour

and amylose content will also influence the fermentative process

1.2.7. Parameters to identify quality of flour streams

There are variety of parameters which indicate the functional properties of streams,

some of these are discussed below. All these values are closely related to mixing, dough

rheology and the baking performance.

a) Ash Contents

Ash content increases with the ER and end streams are usually rich in ash which

are not suitable for biscuit.

b) Polyphenoloxidase PPO

Arabinoxylans present in bran is the major functional component of bran and is

related to the enzyme (PPP) that hydrolyses it, therefore determination of PPO

activity is another valid indicator to evaluate bran contamination in white flour or

for increasing ER (Furest et al, 2006).

c) Protein content

Protein quantity and quality is indirectly a measure of quality of flour. It is

determined by variety of tests such as sedimentation value, LA-SRC, AWRC and

electrophoresis.

d) Particle size

It is the basic requirement in flour mill to evaluate flour quality. Fine particles lead

to produce high damaged starch content with high water absorption.

12

e) Falling number (FN)

It measures indirectly α-amylase activity which is related to get strength of starch

gel in dough. High FN means less α-amylase activity and starch molecule will unite

strongly.

f) Moisture content

Normally high moisture in flour supports softness on dough. Excess must be

avoided to present infestation and microbiological attack.

g) Damaged Starch

Low level of damaged starch is required for biscuit manufacturing. Streams which

have damaged starch lower than 25 UCD or less than 6% must be used for biscuit

production, higher value will support bread and pasta making.

1.2.8. Relationship of milling with end quality of biscuits

The end quality of biscuits largely depends on the process of milling and blending. The

choice for selecting break roll streams for further grinding also change the quality of flour.

Approaching towards the tail streams, the composition is fairly stabilized and drastically

changed. The following end quality properties are closely related to the composite flour

that is obtained after blending all the streams.

a. Diameter of the biscuit

The biscuits get reduced in size if major portion of tail streams rich in ash, protein,

damaged starch and bran is included in blending.

b. Height

Height will be decreased if streams of high damaged starch will be used.

c. Weight

Weight will be increased in specific volume i.e. density will be higher if tail streams

are included.

d. Color

The biscuit is related to most of the above values, the higher ash and protein

content will provide biscuit darker in color.

13

e. Surface crack/top grain

Tail streams will provide less cracking on the surface due to compact nature of

flour.

f. Mouth feel

Excess PPO activity, ash, protein and damaged starch contents provide hard

texture to biscuit and are responsible for adverse mouth feel.

1.3. Wheat flour

The fine powder after grinding of wheat is called wheat flour.

1.3.1. Composition of flour

1.3.1.1. Proteins

There are four types of protein found in wheat kernel,

a) Albumins (soluble in water)

b) Globulins (soluble in salt solution)

c) Prolamins (soluble in 70 to 85% ethanol)

d) Glutelins (soluble in dilute acid)

On hydration, flour form a viscoelastic mass that is called gluten with activated

network. Gluten is actually composed of two protein, gliadin (Prolamins) and glutenin

(Glutelins).

Glutenins are large polymeric proteins held together by many disulfide bonds. These

proteins give strength and elasticity to dough. Gliadins are smaller monomeric

proteins that are responsible for dough extensibility.

1.3.1.2. Starch

Wheat flour contains generally over 70% starch that is composed of

a) Amylose (25%)

b) Amylopectin (75%)

14

Amylose is a primarily straight-chain polymer of α-1,4-linked D-glucopyranose

molecules. Amylopectin is a branched polymer of α-1,4-linked glucose connected by

α-1,6- linked branch points. Starch has the property of absorbing water and cause

swelling when it is heated in excess water.

These properties of starch are important in many aspects relating to flour quality

because they influence the interactions of starch and water in a food system. Starch

granules can be physically damaged during flour milling, increasing their water-

holding ability and susceptibility to be attacked from the enzyme α-amylase.

1.3.1.3. Damaged Starch

The level of damaged starch depends on wheat hardness and milling technique. The

wheat which is harder, needs more force to break out, causing starch granules to be

damaged. Damaged starch increases water absorption of water, make flour

susceptible to α-amylase attack. α-amylase reduces starch into small fragments of

dextrin. Dextrin influences water holding ability and porosity of the dough.

High dextrin quantity softens the dough and make dough sticky, which is unwanted

impact on cookie quality.

1.3.1.4. Pentosans

Pentosans are the constituents of cell walls of wheat endosperm and bran. They are

composed of arabinoxylan which is a polymer with a β-(1-4)-linked D xylopyranose

backbone and branches of L-arabinofuranose.

It absorbs water ten times of its own weight. Pentosans are of both types i.e. water-

insoluble and water-soluble forms, depending on the degree of branching of the

arabinose side chains. A higher degree of arabinose substitution is associated with

higher water solubility.

15

1.3.1.5. Lipids

Whole grain wheat contains approximately 2 to 4% and the endosperm about 1 to

2% crude fats.

1.3.1.6. Ash Contents:

The inorganic residue in flour is called ash. It varies in flour and depends on how

milling is efficiently performed. 0.4% to 0.55% ash is usually considered as good

quality flour.

1.3.1.7. Moisture content:

Moisture is already present in wheat and also added during soaking of wheat. Usually

12-14% moisture is found in flour.

1.4. Ingredients other than flour and their functions

1.4.1. Sugar and syrup

Sugar and syrup being part of the recipe influence the various rheological characteristics

of the biscuit dough and the end quality. Excess of sugar reduce extrusion time, density,

consistency, viscosity and development of gluten network (as elastic recovery is

reduced). Spreading and thickness of the biscuit get increased. Reducing sugars like

dextrose, invert syrup, liquid glucose, fructose, high fructose corn syrup (HFCS) are used

as color improvers, HFCS shows better impact. Substitution of small level of glucose,

fructose, maltose, HFCS for sucrose, change the surface cracking pattern of the biscuit.

This shows that reducing sugars are more effective in determining the top grain (surface

cracking) than non-reducing (sucrose). However only glucose or fructose used as sugar

do not affect surface pattern. Sucrose either dissolved or in granular form exhibit surface

cracking because it crystalizes during baking. The appearance and physical properties of

biscuit such as dimensional properties, shape and surface cracking depend on the type

of sugar used because all the sugars vary in their melting point, solubility and

crystallization pattern.

16

1.4.2. Milk and role of milk proteins in baking

Whole milk liquid/powder and whey powder/whey protein concentrates (WPC) are

frequently used in biscuit production. Although addition of milk or milk products serves

the basic purpose of flavor and nutritional improvement, however milk components

including proteins play role in altering rheological and textural properties of biscuit.

Caseins show more elasticity and many make the texture harder, WPC has been used in

making gluten-free biscuits (Gaines et al, 2006) and shows its functional property to

participate in making gluten network, whey proteins are very strong non gluten proteins

candidate to replace gluten in gluten free biscuits. Milk ingredients leaving caseins make

dough less elastic and improve biscuit end quality as the softness increases while in

mouth feel it shows better mobility in mouth.

1.4.3. Egg and role of egg proteins

The components of egg are regarded as multifunctional additives in variety of food

system including biscuits, egg is sued to improve texture, volume, color, and flavor apart

from enhancing its nutritional value. Egg proteins play distinct role, like egg white

proteins form stronger, tougher and more elastic gel network than the yolk proteins

which provides color and softness to the biscuit. The protein network gets modified also

during mixing, sheeting and baking

1.4.4. Fat or Shortening

Fat plays many roles in baking, but few critical functions of fat are mentioned

underneath.

Slip melting point which shows the start temperature where fat begins to melt, is one of

the critical and major factor of functions of fat in dough.

a) Dough weakening.

Fat when mixed with flour, surrounds the particle resulting in weakening the gluten

network, resulting in baked products to become softer in texture, easily breakable,

chewable and melt in the mouth.

17

b) Creaming

Fat has the tendency to trap air bubbles during beating and mixing of dough which

produces porosity in dough containing many tiny air bubbles that are well trapped in

fat. This is very vital process in baking, the soft and airy texture of the product is

formed due to these air bubbles that expand during baking.

c) Layering

The bakery products other than the biscuit i.e. puff pastry, high melting points fats

are used to produce layers. Fat with high melting points tend to spread inside the

layers of pastry and it will be separated during baking to produce layers or puffs in

products.

d) Flavoring

Commonly all fats that are used in baking must have a plain taste and flavor. This is

required to keep finished product away from changing its own flavor. In rare products

fats are used to impart specific flavor to the baked products for example, using butter

for particular baked goods and lard for meat pie pastry.

e) Emulsion formation

Fat are also used to form emulsion with other ingredients in first stage of mixing

in dough or batter to form dough structure, later flour is added in second stage

of mixing.

1.5. Role of additives in biscuit processing

The additives in baking products have become essential part of the recipe. Additives in

biscuits although were used as flour improvers to ease the processing and to produce the

desired end quality. However, now they serve multiple purposes such as to enhance

nutritive value, to replace the ingredients for cost reduction etc. Variety of substances

are added in bakery products such as oxidizing and reducing agents, enzymes, emulsifies,

hydrocolloids, salts, nutrients etc. The objective of adding each additive is different and

it differ in their chemical nature widely.

18

1.5.1. Specific enzymes used in modification of biscuit dough

Enzymes are widely used in improving the functionality of dough. Different proteases

have been added to hydrolyze the gluten proteins (gliadins or glutenins) to make hard

flour soft by reducing the gluten strength of the dough. Amylases are used to adjust

viscosity and flow of the dough while lipases have served the purpose of altering dough

rheology in variety of ways.

Lipases modify the dough by acting as built in emulsifiers because they hydrolyze the fat

present in the dough partially or fully, if fat is partially hydrolyzed then either mono or

diglycerides are produced which are now used as established emulsifiers. Lipases in the

recipe may reduce the quantity of lecithin or may eliminate it completely. Every lipase,

will produce a different emulsifier and so its functions in dough may be desirable or

undesirable.

1.5.2. Emulsifiers in biscuit processing:

Emulsifiers are commonly added as ingredients to improve dough handling and baking

performance. Emulsifiers are responsible for promoting gluten and fat interactions that

makes the end product soft and provide better mouth feel. Lecithin, diacetyl tartaric acid

ester of monoglycerides (DATEM), mono and diglycerides (MGD) are commonly used

individually and in combinations. Biscuit recipe consists fat as a major component next

to flour and role of emulsifiers may hardly be ignored to make a desired product.

Emulsifiers play their role as anti-staling agent in bread. Emulsifiers are responsible for

changing the secondary structure of gluten proteins affecting the texture of end

products.

1.5.3. Oxidizing and reducing agents

Oxidizing and reducing agents are commonly used in flour treatment for variety of

purposes, such as for breaking dough strength/baking performance. Chlorine is used to

bleach the various pigments present in bran. Some oxidizing chemicals act as maturing

agents as chlorine dioxide, acetone peroxide, azodicarobonamide, potassium borate,

potassium iodate (a rapid dough breakdown agent). Potassium iodate and

19

azocarbonamide are fast acting oxidant and give similar effect as given by activated

dough bond compound. The reducing agents break the disulfide bridge of the large

glutenin molecules and make protein molecule size smaller than get hydrated easily and

dough mixes well reducing the mixing time. The reducing agents such as cysteine, sodium

bi-sulphite and sodium meta bisulfite are often used as flour improvers.

1.5.4. Hydrocolloids

The significance of functional importance of hydrocolloid in modifying dough rheology

and baking performance is being gradually understood in baking industry. Hydrocolloids

are hydrophilic biopolymers widely distributed in food systems, they affect water take up

by different molecules in the recipe by interacting with water ions and thus alter the

swelling, gelatinization, viscosity and gelling properties of the mix (dough). Hydrocolloids

are used as improver in bread, cake, biscuit and other bakery products. Some of the

hydrocolloids have been used as gluten replacers in the gluten free products as they are

capable of inducing viscoelastic, hydration and gas binding (gas retaining) properties.

Common hydrocolloids include gums (xanthan, guar, arabic), carbomethoxy cellulose

(CMC), non-starch polysaccharides (NSP) such as celluloses and hemicelluloses, beta

glucan, arabinoxylans, dietary fibers etc. Some of the emulsifiers also act as hydrocolloids

because they promote lipid gluten and lipid starch interactions in dough making process.

The gel rheology of the dough gets improved in presence of hydrocolloids which seems

to be a requisite for establishment of continuous network structure of the dough.

1.6. Mixing

1.6.1. A process of dough development

Mixing is an integral and the most critical part of any baking industry because the

mistakes you make here will appear in baking i.e. in end quality and there will be no

possibility for correction. Mixing is the process where all the ingredients in appropriate

amounts are blended and they interact to achieve the uniform distribution of each to

produce a mass of desired consistency, the mass is named as “dough”. So mixing is a

process of dough development that is highly important, complex, focal and need skilled

20

handling. Mixing time of the dough depends on the recipe of biscuit and may take 5-25

minutes.

1.6.2. Reactions in mixing

Variety of reactions take place during mixing to properly develop the dough. These

reactions may be inter ingredients or intra ingredients for example a component of flour

say protein may interact within itself or may react with another component (starch). It is

also possible that protein/starch in flour may react with sugar, fat or other ingredients.

The dough development is therefore a process of multiple visible and invisible stages,

where variety of reactions are taking place to develop gluten network, gluten-starch

matrix formation etc. The other molecules (ingredients) are embedded in the network

uniformly to produce desired viscoelastic mass or the dough. Some of the visible stages

of dough development are briefly discussed here, which are actually the outcome of

chemical reactions (invisible)

a. Formation of many electrostatic bonds between water molecule and

protein/starch.

b. Formation of new di-sulphide bridges that generate gluten network.

c. Protein starch linkages that develops protein matrix

d. Starch- starch interactions that shape a starch granule embedded in

protein network.

e. Non peptide linkages formation as a result of reactions of protein with

oxidizing and reducing agents

f. Enzymatic hydrolysis of peptide ester linkage of fats, acyle bond of

starches and their interactions in between themselves.

g. Formation of starch – fatty acids enclosures.

In fact many more such reactions are simultaneously occurring that finally give the shape

to dough. Some stages in mixing which are very visible, are being briefly discussed here.

21

I. Pick up

It is the process of hydration of each ingredient but the water taken up is not

absorbed or interacted. The mix is sticky with lumps and is cold. It shows ratio of

the hydrophilic and hydrophobic ingredients in a recipe.

II. Initial development

Water is penetrating and acting as a bridge between molecules, dough is smooth,

dried and hold temperature gets warmer.

III. Clean up

Dough is getting as one mass and scattered ingredients interact firmly to make it

stiff and together. Changes in color are obvious because of molecular interaction.

The dough now is lumpy, irregular and hard. It is the “under developed dough”.

IV. Final development

During the process of further mixing the dough has gained elasticity, desired

gluten network is at final stage i.e. s-s-bridges with in the glutenin and in gliaden

– glutenin have been sufficiently formed, arabinoxylan and starch interlinkages

have been developed to hold other molecules to provide the appropriate

viscosity. The temperature of the dough is suitable for handling, the dough which

at this stage may be called as the “optimal dough”, the dough ready to be baked.

V. Let down

The dough is very warm and viscous with more flow and less elasticity. The

molecular interactions if exceed than desired, the dough becomes very soft and

mobile.

VI. Breakdown

The inter molecular bridges i.e. s-s-and ferulic acid, protein-protein cross linking,

starch-protein, starch – starch (amylose-amylopecin with fat linkages) are

breaking and dough is getting weak, beginning to liquefy. The dough at this stage

may be called as “over developed”.

VII. Ideal dough

The ideal desired dough / optimal dough for each product (for each recipe) is

different and is obtained by controlling of the temperature at each stage, mixing

22

time and speed of mixer etc. Its temperature, density, weight, viscosity etc.

should be recorded as a check parameters to control quality of the dough that

determines quality.

1.6.3. Identification of optimal dough:

Optimal dough is the dough which produce the desired product on baking. It must be

thoroughly examined before baking because once the end product is obtained, the

process is irreversible. The parameters (tests) to assess the quality of optimal dough must

be highly reliable and dependable. Some of the tests to identify optimal dough are

discussed below.

a. Baking performance

The most reliable is the baking test, however it takes time. Some rheological tests using

Mixolab, texture analyzers and alveograph etc. provide information about pre baking

quality of dough. However quick tests are needed to decide whether the dough should

be baked or recycled such tests are discussed here.

b. Dough density

It predicts dough baking performance and end quality. The shape, weight and

dimensional characteristics are evaluated by studying the density of dough which may

easily be determined by dipping (immersing) a known weight of dough into an immiscible

liquid (water), the formula weight/volume will give the density.

c. Temperature of dough

The temperature of the dough before entering the oven is very important and should

coordinate with the temperature of 1st oven zone. Dough temperature at the beginning,

middle stage and end stage is also important. The dough temperature rises because of

inclusion of heat of hydration, heat of friction and environmental temperature that affect

the intermolecular reactions and the end properties. The rise in temperature during

mixing may be approximately calculated by friction factor which is defined as the value

23

used to compensate for the increased length of time. The friction factor is calculated by

the following formula,

3 x t 0C (dough) - t0C(room)+t0C (flour) + t0C(water) = Friction factor

d. Water absorption

Known amount of dough placed on a paper and pressed with a known weight will

produce wetted area on paper that is inversely proportional to water withheld and is

related to texture, surface crack etc.

e. Fat absorption

It is determined in the same way as the water absorption and is related to color and the

softness of the biscuit.

f. Hexane stability test

It gives amount of unabsorbed fat in the dough which is related to color, spread ability

etc. Expert bakers use their own way of thumb pressing, area of fat on filter paper, stretch

ability etc. Such tests at the end of mixing and before baking are important to reduce the

unwanted wastage.

g. Thumb Impression

Smooth dough when pressed with thumb makes depression, how quickly the dough

detains its original appearance predicts the dough baking performance.

Expert bakers may feel the dough behavior well in baking and such simple tests may

further help to predict the end quality and in identifying the desired dough.

1.6.4. Dough as a predictor of end quality

Bakers have to realize that dough before baking is the true predictor of end quality and

during dough development, variety of changes in process may change the dough

rheology and baking performance. As multiple reactions are going on during dough

development, it is necessary to promote certain reactions and to restrict also

24

considerable reaction to achieve the best performance of the dough. “Resting of the

dough” for a short period of time may be a good option that may reduce mixing time and

to save energy. Many of the reactions presently going on may get time to be completed.

Resting of dough is often desirable if enzyme are used.

1.7. Baking

1.7.1. Reactions in baking

It is interesting to see that how a flattened piece of dough get the attractive shape

appealing and a yummy taste just after spending few minutes in various sections of oven.

It is because the complex molecules as protein, fat, starch interact in multiple ways in

presence of water and heat. We have already hydrated these molecules during mixing

and provided the facility to them to swell that initiate inter molecular associations that

promote reactions in baking. Baking is actually a process of series of chemical reactions

responsible for visible physical changes i.e. formation of biscuit shape, appearance and

flavor. Some of these reactions are briefly discussed here.

a) Vaporization and mobility of water

The water present in dough vaporizes slowly as the dough enters in the oven. The

vapors moves horizontally (from center to sides) and vertically (from bottom to top)

that causes dough to expand and it dries gradually forming the structure. The

hardness, color, height and diameter of the biscuit may be controlled by varying the

speed of oven band, temperature and humidity in each zone of oven that determines

the texture of the biscuits percentage of moisture loss in each zone is a control of

quality of biscuit.

b) Caramelization

The process of caramelization brings three distinct changes in biscuit, firstly color,

secondly flavor and thirdly texture (crispiness). Caramelization in brief is a process of

burning of sugar in absence of moisture that causes color change from yellow to

brown, flavor development as burnt, bitter, acrid texture and formation. The above

25

observation are a result of multiple, chemical reactions between unsaturated

compounds forming complex polymers that are mostly saturated.

c) Maillard reaction

Maillard reaction is a group of reactions that includes condensation, addition and

polymerization reaction in series. It begins when water evaporates from dough and

condenses in dough an group of a protein to react with aldehdic group of starch to

form an amide. Many such reaction products go through polymerization to produce

compounds of brown color, burnt flavor and hard texture. Millard reaction also plays

key role in giving appearance, color and taste to biscuits.

d) Protein modification

Variety of proteins are present in dough which change or modify their structures when

heat is provided and water evaporates. Firstly coiled structure of protein is decoiled

and it aggregates that change in protein is known as denaturation or coagulation of

protein. This thermal denaturation at a temperature of 60-70 °C causes protein to

release water during uncoiling the released water (Proteins absorbs 31% water) is

taken up by starch which at further higher temperature > 74 °C gets gelatinized around

air bubbles, forming rigid structure due to protein and starch binding. All these

reactions help in texture formation of biscuit. Texture development is a complex

process of multiple reaction where ingredients added water and thermal environment

play their roles.

e) Starch gelatinization

Starch gelatinization is at least a three step process, firstly the starch granules hydrate

themselves, secondly the starch starts swelling at 40 °C, thirdly they start losing water

at higher temperature (simultaneously they bind protein) to from gel and finally to

become rigid in structure by losing water from gel. Starch is the most abundant

molecule in dough as flour consists nearly 68-82% of starch. Texture formation is

therefore mostly controlled by starch gelatinization.

26

f) Enzyme inactivation

The two groups of enzymes that mostly participate in baking are amylases and

proteases. Amylases accelerate the starch break down that makes dough more fluid,

mobile and promotes expansion. If enzyme is activated early the expansion or

spreading will be limited. Similarly proteases cause protein to hydrolyze that release

water also and will affect starch gelatinization and starch binding. Protease will cause

structured change.

g) Cell structure formation

The air bubbles in dough get reduced in baking depending on the heat provided. The

cell structure is different in crust (upper surface) and crumb (inter structure) the size

of cells in both are different and they are more compactly packed in crust as compared

to crumb, that has to be controlled in baking to give the desired mouth feel, chewing

and biting properties. All these reactions control the end quality.

1.7.2. Role of Ovens in Baking

Industrial baking ovens are generally called as tunnel ovens they consist of long

conveyors which carry the biscuit pieces through a heated tunnel section of the baking

chamber. The length of oven may differ from 25 meter to 100 meter. Two type of the

conveyor bands are available referred as wire-mesh and carbon steel band. The time of

baking and temperature are the two major factors in controlling the baking performances

of biscuit. The baking time is set if conveyor is driven with variable speeds.

1.7.3. Baking Zones

Industrial baking ovens are usually divided into zones accordingly to the differences in

the temperature and humidity which are controlled in zones along the length of the oven.

Most of the industrial baking ovens are based on 4 to 6 zones. The purpose of the

different zones system is to adjust temperature and humidity at suitable values during

the baking. The environments of the zones thus created will boost the developing of the

27

biscuit structure at suitable parameters such as moisture, top grain and color to get the

desired end quality.

The moisture removed from the biscuit dough depends on the extraction unit in every

zone which is linked to the speed of the conveyors. A fan is used to draw moist air from

baking tunnel for the exit of the moist air to chimneys and finally to atmosphere that

determines the extraction units.

There are three types of oven used in professional baking oven,

I. Radiant - Direct gas fired ovens and indirect radiant that is called cyclotherm

ovens

II. Conduction– The mesh bands or steel bands that are used pre-heated

III. Convection – They may be direct and indirect.

1.7.4. Hybrid ovens

Commercially a combination of different oven types are used in the form of zones that is

called “hybrid” or “combination” oven. The advantage of hybrid ovens is that different

heat transfer modes may be used at different stages of the baking process.

Table 2: Combination of zone used for commercially baked biscuits in Hybrid ovens

Zones

For semi hard/Sheeted product

i.e. biscuit and cracker

(wire mesh band)

For soft product i.e. cookie

(steel band)

01 Direct fire Cyclotherm

02 Direct Fire Cyclotherm

03 Cyclotherm Cyclotherm

04 Convection Convection

05 Convection Convection

28

2. CHAPTER: MATERIAL AND METHOD

2.1. Materials

Materials are separately discussed in each study or investigation. Please refer sections

“3.1.2.”, “3.2.2.”, “4.1.2.”, “5.1.2.”, “5.2.2.”, “5.3.2.”, “6.1.2.” and “6.2.2.” for the

description of materials.

2.2. Methods

2.2.1. Physicochemical Analysis

Instrumental Analysis

2.2.1.1. Moisture Content

Brabender Moisture Tester (Germany) was used to determine moisture contents of flour.

9 - 11 gm flour was dried at 155 °C as per AACC approved method no. 44-19.

Note: Results of moisture analysis have been discussed in the sections i.e. “3.1.3.1.”,

“3.2.3.1.”, “4.1.3.3.”, “5.1.3.1.”, “5.3.3.1.”, “6.1.3.1.” and “6.2.3.1.”

2.2.1.2. Analysis using Kernelyzer

Total protein, zeleny value and ash contents were analyzed by using Brabender

Kernalyzer. Ash is a critical parameter which identifies the flour quality with respect to

milling efficiency. Amount of ash in flour is also a legal requirement of PSQCA (Pakistan

Standard Quality Control Authority) which need to be fulfilled according to a baking

industry.

Normally ash is determined through muffle furnace method which takes at least 6 hours

to produce the result, it also involves manual handing which produce results where

accuracy may be challenged. Kernelyzer is a nondestructive testing machine which gives

results in seconds. Keeping time limitation and accuracy in result, Kernelyzer is used in

most of the commercial industries.

Note: Results Kernelyzer have been discussed in the sections i.e. “3.1.3.1.”, “3.2.3.1.”,

“4.1.3.2.”, “4.1.3.3.”, “5.1.3.3.”, “5.2.3.1.”, “5.3.3.1.”, “6.1.3.1.” and “6.2.3.1.”

29

2.2.1.3. Vibratory Sieve shaker to determination the particle size

The distribution of particle size in flour was measured by a vibratory sieve shaker

(Oberstein, Germany). Two sieves of 160 to 125 micron was used with vibration of 2 mm

amplitude for the time period of 10 min.

Note: Results of particle size analysis have been discussed in the sections i.e. “3.1.3.1.”,

“3.2.3.1.”, “4.1.3.3.”, “5.1.3.3.”, “5.2.3.1.”, “5.3.3.1.”, “6.1.3.1.” and “6.2.3.1.”

2.2.2. Farinograph Analysis

The flour behavior during dough making (rheological properties) were analyzed on

Brabender Farinograph (Duisburg, Germany) as per approved method of AACC (method

54-21). Farinograph Quality Number (FQN), Water Absorption (WA), Dough Stability Time

(DST), Dough Development Time (DDT) and two type of Degree of Softening (DoS) (ICC -

12 min after peak time and 10 min after beginning of curve) were determined.

The flour samples (300 gm) consisting 14 % moisture content were placed separately in

the mixing bowl of Farinograph. The line of 500 Farinograph Unit (FU) was reached, water

was poured by using already installed burette.

a) Dough development time (DDT)

DDT that is also called “peak” or “peak time” is the time when water is first added till it

reaches to maximum consistency of dough and dough moves slowly. It also indicate the

mixing time of dough.

b) Dough stability (DST)

Dough stability time is the time of difference in arrival and departure time. Arrival time

shows the time when peak first touches 500 FU line while departure is the time when

peak departs from 500 FU. DST is a measure of dough strength that how long the dough

may remain unchanged and is not deformed.

30

c) Degree of Softening (DoS)

DoS of the dough is measured in two ways. It is the difference in torque (FU) from peak

at the top of the curve measured either 12 min after peak time or 10 min after the

beginning.

d) Water Absorption (WA)

It is the amount of water required to be absorbed by the flour to form a consistent dough

at 500 FU. The water absorption value changes according to the quality of flour and the

ingredients in recipe. Hard flour need more water to reach required consistency of the

dough.

e) Farinograph Quality Number (FQN)

Farinograph quality number suggests the overall nature of the dough. High FQN reflects

strong dough network, while low FQN indicates weak dough.

Note: Results of farinograph have been discussed in the sections i.e. “3.1.3.2.”,

“3.2.3.3.”, “4.1.3.4.”, “5.1.3.2.”, “5.2.3.3.”, “5.3.3.2.”, “6.1.3.3.” and “6.2.3.2.”

2.2.3. Micro Visco-Amylo-Graph (MVAG) Analysis

MVAG (Brabender, Duisburg, Germany) was used to determine pasting properties of

starch present in wheat flour. Approved method of AACC (AACC Method 22-12) was used

to analyze wheat flour. A 15 gm flour sample was weighed and transferred into the bowl

provided with MVAG and then distilled water around 100 ml was added. The quantity of

water was adjusted as per the moisture content present in flour. Slurry was initially

formed by shaking with hands, then the bowl was fixed in MVAG. Slurry was stirred at

160 rpm and heated to 35°C for 10 sec and then heated to 95 °C for 7.3 min. During the

holding period, slurry was held heated at 95 °C for 15.7 min. Finally it was cooled to 50

°C for a period of 7.7 min. Beginning of Gelatinization, Max Viscosity/Peak Viscosity (PV),

Break-Down (BD) and Setback (SB) were estimated.

31

a) Pasting Temperature

The capacity of starch to swell depends on ratio of amylose and amylopectin, their chain

length, total concentration and chemical structure of the two component of starch

granule. The swelling shows the ability of starch molecules to inbide water and depends

on the pasting temperature which is defined as the temperature at which the fluid gets

viscous. It also determines beginning of gelatinization. The MVAG measures the pasting

temperature that helps to regulate the temperature of zone of baking oven. The excess

of starch granules lowers the pasting temperature while small molecules as

glucose/maltose lead to high pasting temperature.

b) Peak Viscosity/Maximum Viscosity

Peak viscosity of the starch molecule is related to its ability to swell and form paste on

heating in water, if the paste is concentrated viscosity will be higher because the pins of

the mixer will resist during stirring and will show higher viscosity. The ability of the paste

to resist movement during stirring is called the peak viscosity. It is related to overall end

quality of biscuit.

c) Hot Paste Viscosity

It is the viscosity measured at the end of heating process and determines the mobility of

swollen starch granules after cooking for 20 minutes. Viscosity at this stage is decreased

and is known as the breakdown viscosity. Which is calculated by subtracting the hot paste

viscosity from peak viscosity. The hot paste viscosity is related to hardness of the end

product.

d) Cold Paste Viscosity

It is the viscosity measured at the 300C or the 500C and is higher than the hot paste

viscosity or breakdown viscosity because the amylose molecules now reunite making

the paste thicker. This phase is refereed as retrogradation of starch when more H-

bonds are formed between adjacent hydroxyl groups of amylose units. The cold paste

viscosity is related to mouth feel property of biscuits.

32

e) Setback Viscosity

The SB viscosity involves recrystallization of starch which shows the closing of double

helices and viscosity increases. It is calculated by subtracting peak viscosity from cold

paste viscosity which is also named as final viscosity. All the viscosities at cold

temperature are related to chewing, biting or mouthfeel properties and elaborate the

eating quality of the biscuit or the biscuit texture.

Note: Results of MVAG have been discussed in the sections i.e. “3.1.3.3.”, “3.2.3.4.”,

“5.2.3.4.”, “5.3.3.3.”, “6.2.3.3.” and “6.1.3.4.”

2.2.4. Glutomatic Analysis

Different analysis on gluten proteins were conducted on Glutomatic System - 2000

(Perten, Sweden) as per approved method 38 - 12 (AACC, 2000). The dry gluten (DG), wet

gluten (WG), passed gluten (PG), retained gluten (RG), gluten index (GI) and water

binding capacity (WBC) were the parameters analyzed using Glutomatic System. 10 gm

flour sample was placed on cups with polyester sieve and fixed in the washing chamber

of Glutomatic. 2% saline water was used to wash the flour for 5 min. The residue i.e. wet

gluten was collected on cups and then placed in centrifuge machine to get passed and

retained gluten separated through a perforated mesh already installed inside the holder

cup.

a) Gluten Index:

The Gluten Index is a measure of gluten strength or the gluten network of the dough

and is calculated by the formula GI = (Retained gluten)/100.

b) Wet Gluten:

Wet Gluten is a predictor of few qualities of the flour. It measures water binding

capacity of the gluten proteins, thereby indicating the behavior of gluten proteins

during mixing and baking. The amount of wet gluten shows hardness of the flour and is

measured by Glutomatic 2200 using method 38-12 (AACC-2000) proteins.

33

Note: Results of glutomatic proteins have been discussed in the sections i.e. “3.1.3.1.”,

“3.2.3.5.”, “4.1.3.3.”, “5.1.3.4.”, “5.2.3.5.”, “5.3.3.4.”, “6.1.3.5.” and “6.2.3.1.”

2.2.5. Determination of Damaged Starch Content by SDmatic

Damaged Starch content was analyzed by using Chopin Sdmatic. The Sdmatic from

Chopin is designed to measure starch damage rate of the flour in Ai %( iodine absorption)

and in UCD (Chopin Dubois Unit). The Sdmatic works on the Medcalf and Giles Principle

(1965) to measure the starch damage rate of flour.

Briefly describing, 120 ml of distilled water in plastic bottle is taken, 1.5 grams of citric

acid, 3 gm of potassium iodide with 1-2 drop of sodium thiosulphate at 0.1 mol/l were

added. Bottle was shaken for seconds and then poured into a reaction solution in reaction

bowl of Sdmatic system. Reaction bowled was placed in the Sdmatic and folded down the

arm. 1 gm of flour was weighed in the spoon and placed in the Sdmatic. Flour weight,

moisture and protein level were fed in the software and the test was started. Results

were shown in UCD, % according to AACC 76-31and also in Farrand.

Note: Results of DS have been discussed in the sections i.e. “4.1.3.3.”, “3.2.3.1.”, “5.1.3.3.”

and “5.2.3.1.”

2.2.6. Scanning Electron Microscopy (SEM)

SEM (Analysis system, Model JEOL-2300) was used to evaluate dough microstructure

according to Prabhashankar and coworker (2004). Samples of dough were kept in hexane

for 16 hr to defat it. After fat removal, dough was dried by freezing for 5-6 hr. For sample

preparation to analyze in SEM, dried dough was cut (transversally) into fine slices by using

blade considering no damage of the dough structure. After mounting on the holder

further studies were taken place to produce picture.

Note: Results have been discussed in the section of “6.2.3.4”.

34

Chemical Analysis

2.2.7. Solvent retention capacity

Different type of Solvent retention capacity (SRC) analysis were conducted as per the

approved method of AACC 56 - 11 (AACC 2000). All SRC are discussed below,

a) Water SRC

1 gm of flour sample (each) was added in tube with 5 ml of water. The suspended flour

samples were held hydrated for the period of 20 min (shake for 5 second after 5, 10, 15,

and 20 min). After 20 min tube were placed in centrifuge tube with 1,000 rpm for the

period of 15 min. The supernatant in the tube was decanted and then tube was placed

on a paper towel at 90° angle to drain it for 10 min. The remaining centrifuged part of

flour was weighed. The SRC value was calculated as per the method derived by Haynes

and coworkers (2009). The analysis for each sample was conducted in duplicate.

b) Sucrose SRC

1 gm of flour sample (each) was added in tube with 5 ml of 50% sucrose. The suspended

flour samples were held hydrated for the period of 20 min (shake for 5 second after 5,

10, 15, and 20 min). After 20 min tube were placed in centrifuge tube with 1,000 rpm for

the period of 15 min. The supernatant in the tube was decanted and then tube was

placed on a paper towel at 90° angle to drain it for 10 min. The remaining centrifuged

part of flour was weighed. The SRC value was calculated as per the method derived by

Haynes and coworkers (2009). The analysis for each sample was conducted in duplicate.

c) Lactic Acid SRC

1 gm of flour sample (each) was added in tube with 5 ml of 5% lactic acid. The suspended


10, 15, and 20 min). After 20 min tube were placed in centrifuge tube with 1,000 rpm for

the period of 15 min. The supernatant in the tube was decanted and then tube was

placed on a paper towel at 90° angle to drain it for 10 min. The remaining centrifuged

35

part of flour was weighed. The SRC value was calculated as per the method derived by

Haynes and coworkers (2009). The analysis for each sample was conducted in duplicate.

d) Sodium carbonate SRC

1 gm of flour sample (each) was added in tube with 5 ml of 5% sodium carbonate solution.

The suspended flour samples were held hydrated for the period of 20 min (shake for 5

second after 5, 10, 15, and 20 min). After 20 min tube were placed in centrifuge tube with

1,000 rpm for the period of 15 min. The supernatant in the tube was decanted and then

tube was placed on a paper towel at 90° angle to drain it for 10 min. The remaining

centrifuged part of flour was weighed. The SRC value was calculated as per the method

derived by Haynes and coworkers (2009). The analysis for each sample was conducted in

duplicate.

Note: Results have been discussed in the sections i.e. “3.1.3.4.”, “3.2.3.2.” and with other

physicochemical analysis.

2.2.8. AWRC profiles of flours:

The AWRC was conducted as per approved method of AACC 56-10, 1 gm of flour sample

(each) was added in tube with 5 ml of NaHCO3 solution (8.4g in 1 liter). The suspended


10, 15, and 20 min). After resting for 20 min, the tubes were centrifuged at 1,000 rpm for

the period of 15 min. The supernatant in the tube was decanted and then each tube was

placed on a paper towel at 90° angle to drain the fluid for 10 min. The remaining

centrifuged part of flour was weighed. The AWRC value was calculated as per the method

derived by Haynes and coworkers (2009). The analysis for each sample was conducted in

duplicate.

Note: Results have been discussed in the section of “5.2.3.2.”

2.2.9. Statistical Analysis

The simple statistical techniques using Microsoft Excel (2010) were mostly used to

analyze the data. Tools including linear correlation coefficients between different

36

parameters, scattered chart and line/bar chart were utilized. The SPSS statistical software

(version 20) was used for SEM study.

The values shown in each investigation are a mean of at least three readings.

The reason of including very simple statistical analysis in the study is to focus the milling

industries in Pakistan who are not well developed, they can easily interpret and apply

results in their industries to get the benefit from these studies.

2.2.10. Evaluation of biscuit end quality

The end quality of biscuits was evaluated under the following heading

a) Dimensional analysis

The biscuit dimensions i.e. size, thickness including weight were measured and recorded

as per AACC method (10-31B). Sample for measurement was randomly selected. The

diameter of the biscuit was measured in mm by turning at different angles three times

and the mean value is reported. The thickness of biscuits were measure by placing eight

biscuits in a column and taking average of one biscuit in mm.

The cookie factor/spread ratio was calculated by dividing width (W) by height (H)

according to Colombo et al (2008).

b) Textural analysis

The hardness of biscuit was measured by UTM (Zwick/Roel). Force was calculated on N.

c) Sensory analysis

The 10 trained panelists from English Biscuit Manufacturers Pvt. Ltd. Conducted the

sensory evaluation by using a nine point Hedonic scale. One (1) represented “extremely

dislike” and nine (9) represented “extremely like”. Texture, color, flavor, taste and overall

acceptability level were the attributes for sensory evaluation.

Note: Results have been discussed in the sections i.e. “3.2.3.6.”, “5.3.3.5.”, “6.1.3.6.”,

“6.2.3.5.” and “6.2.3.6.”

37

3. CHAPTER: WHEAT MILLING AND ITS INDUSTRIAL APPLICATION

3.1. Study of milling streams used in the production of commercial flours

to be utilized in biscuit making industry.


Miller, usually face difficulties to produce flour as per customer requirement due to the

uncontrolled supply chain of wheat in Pakistan especially if they have to supply same

quality of flour for longer period of time or permanently. Milling industries are also in

transition period to be modernized by installing state of the art plants and inducting

excellent human resource to face the challenge of supplying flour as per customer need

inspite of the issue of unavailability of required type of wheat kernels.

The study was conducted to evaluate the physiochemical and rheological properties of

milling streams produced in a mill to identify required quality of flour and match with the

different specifications for the customers by mixing selected streams to get composite

flour.

38

Figure 3: Flow chart of milling streams for flour collection

PN: Numeric values are representing the sieve size in micron, alpha numeric values are

representing the streams name. Purifier is actually called Suji machine in Pakistan.

39

3.1.2. Material and Method:

Please refer to chapter 2 for detail description of the methods, however only specific

material and method related to the topic are discussed here.

3.1.2.1. Material

Soft wheat from Punjab origin was milled commercially in Garibsons Pvt. Ltd. Port Qasim,

Karachi, Pakistan. Total 35 flour streams (all type) were studied and samples were

collected accordingly.

3.1.2.2. Information on milling streams used in the study

The final product or the composite flour as commercially practiced in Pakistan is

produced by mixing of the various milling streams/passages as mentioned below

(definition and description were discussed in table 3).

a) Break Streams

b) Middling Streams

c) Fine and Coarse Semolina Streams

d) Semolina Overtail Streams

The final product actually represents the composite flour or a mixture of all the above

mentioned streams. The 132 micron sieve size of sifter was fixed at the mill for getting

flour to be mixed in last stage for adjusting the quality and quantity of the final product.

Some flour streams after sieving from 150 or 180 micron sieves were also used to

increase the extraction rate of flour and to meet the customer order (required quantity).

However, all other quality parameters were achieved within the range of customer’s

specification even after mixing the larger particles size flour.

Table 3: Streams names, types and description

S. No Strea

ms Name

Name of Streams after combining similar streams

Type of Streams

Description of streams

1 B1A

1st Break Break Streams

Wheat is broken by the set of grooved rollers and converted into the many fractions varying in particle size. All fractions are passed through

2 B1B

3 B1C

4 B2A 2nd Break

40

5 B2B the different sieves in huge sifters. The particles which are collected after the end of sieve of 132 or 180 micron are diverted to be mixed into the end product. Whereas the rest of the fractions are further processed by smooth rollers (reduction rollers) to extract remaining flour of different particle size.

6 B2C

7 B3A

3rd Break 8 B3B

9 B3C

10 B4A

4th Break 11 B4B

12 B4C

13 B4D

14 B5A 5th Break

15 C1A Coarse - C1A

Fine and Coarse

Semolina Streams

Portion of ground wheat from break rolls, which has particle size in between 1020-820 micron to 720-530 micron goes to purifiers for the separation of bran, then these fractions are processed by set of rolls and streams are produced called coarse semolina streams, whereas particle between 720-530 to 280-270 micron goes to other purifiers, including the other set of RR and these passages called fine semolina streams. The flour of particle size that is collected after the end of sieve of 132 or 180 micron are diverted to be mixed into the end product flour. Rejection of both the purifiers are diverted to C1B whereas end residue is diverted to bran rich products.

16 C2C Fine - C2C

17 C2A Fine - C2A/B

18 C2B

19 C3A Fine - C3A

20 C1B C1B Semolina Overtail

Streams/ Rejection

from Semolina Streams

Rejection/retained of purifier (Suji machine), goes to other roll sets for further grinding. Flour received after sieving from 132 micron sieves are diverted to be mixed in the final product.

21 C4A C4

22 C4B

23 C5A C5

24 C5B

25 C6A C6

26 C6B

27 D1A D1

Middling Streams

Retained wheat part on 132 or 180 micron sieves from the break roller, goes to other set of smooth rollers for further grinding. In each roller set, flour is achieved after passing it through 132 micron sieve.

28 D1B

29 DD1A DD1

30 DD1B

31 R1A R1A

32 C7A C7A

33 C7B C7B

34 C8A C8

35 C8B

41

The large scale size flour mills usually use more than one set of two rolls for same streams

to get the high grinding rate (extraction rate).

The flours from roller sets consisting similar values were mixed and the number of milling

streams were reduced to 19. Underneath discussion is based on the 19 milling streams.

Table 4: Milling streams type and details

S. NO Streams/Passages # of

streams Name of streams

1 Break Rolls 5 1st, 2nd , 3rd, 4th and 5th Break

2 Fine and coarse

semolina

4 Coarse C1A, Fine C2C, Fine C2A/C2B

and Fine C3A

3 Semolina Overtail 4 C1B, C4, C5 AND C6

4 Middling 6 D1, DD1, R1A, C7A, C7B AND C8

The numbers of streams mentioned above were assigned by the Mill as themselves that

differ from mill to mill.


3.1.3.1. Physicochemical Analysis of Milling Streams

3.1.3.1.1. Moisture

The moisture is a critical parameter for optimizing flour quality for the manufacturing of

biscuits and cookies. It plays vital role in indicating the flour behavior in dough

development and water may need adjustment in the recipe. The moisture is also

responsible for control of dimensional properties of biscuit.

a. Moisture in flour from break passages

Moisture contents in the flour streams decreased gradually from the initial moisture 16%

(wheat) to 12.29% in flour. The moisture amount recorded in break rolls decreased from

15% to 12.29% that clearly indicated that the wheat flour fractions were losing moisture

during milling because of the heat generated by friction energy. The overall moisture loss

in break roll was 2.72% during milling from 1st to 5th break.

42

Figure 4: Variation in moisture (%) in flour from break streams.

b. Moisture in flour from semolina passages

The moisture was recorded as 13.14% in flour taken from coarse semolina whereas

12.26% to 12.94% moisture was observed in flour produced from three streams of fine

semolina. Total 0.68% decrease in moisture was observed in three streams of fine

semolina that was a negligible loss in moisture.

Figure 5: Variation in moisture (%) in flour from semolina streams.

c. Moisture in flour from semolina overtail passages

The moisture loss as 12.88% to 11.72% was recorded in these four streams. Lower

moisture content was evident in semolina overtail passages.

15.0114.47

13.7313.22

12.29

1st Break 2nd Break 3rd Break 4th Break 5th Break

13.14

12.9412.83

12.26

Coarse - C1A Fine - C2C Fine - C2A/B Fine - C3A

43

Figure 6: Variation in moisture (%) in flour from semolina overtail streams

d. Moisture in flour from middling passages

The decrease in moisture content was also observed in the flour streams of middling. C7A

and C7B were the streams found with very low moisture content even up to 11.7%. The

first three flour middling stream had higher moisture level (13.21%-13.87%) with a

difference of 0.66% while the last three streams had shown very low moisture level

(12.3% - 11.7%) with a difference of 2.17% from the highest moisture of middling stream

(13.87%).

Figure 7: Variation in moisture (%) in flour from middling streams

e. Conclusion

The percent moisture was decreasing as milling further proceeded i.e. the particle size

was reduced constantly (as mentioned in 3.1.3.1.7). Higher moisture contents were

observed in break streams whereas the flour from middling, overtail and semolina

12.88

11.72

12.02

12.39

C1B C4 C5 C6

13.47

13.87

13.21

11.84 11.70

12.30

D1 DD1 R1A C7A C7B C8

Moisture (%) in Flour Streams from Middling

44

streams showed similar values of moisture. Along with the recipe water, the moisture

already present in flour is very important in producing required dough (Wade et al, 2012).

3.1.3.1.2. Protein

The total proteins content include all types of proteins present in the flour (including the

gluten proteins). Since gluten plays the determining role in the evaluation of flour quality,

dough making and texture formation of biscuit, it is separately analyzed in the laboratory.

Total protein analysis is therefore not an only significant parameter to predict flour

behavior on production lines (Gaines et al, 2006; Fustier et al, 2009).

a. Protein content in flour from Break passages

Protein content was found to be increasing as the wheat kernel was getting milled,

10.23% protein was reported in the flour from 1st break whereas highest amount of

protein as 13.97% was observed in flour from 3rd break. Increase in protein was due to

the inclusion of bran that is a rich source of bran proteins.

Figure 8: Variation in protein (%) in flour from break rolls streams

b. Protein content in flour from Semolina passages

Quite consistent amount of protein was found to be present in 4 streams from semolina

(10% to 10.4%). Similar like gluten, the low protein content in flour is perfect for cookie

making in baking industry.

10.23

12.40

13.9713.33

12.60


45

Figure 9: Variation in protein (%) in flour from semolina streams

c. Protein content in flour from Semolina overtail passages

Increase in protein content as 10.15% to 11.3% was recorded in overtail streams of

semolina due to the inclusion of bran. Bran proteins are widely distributed in pericarp.

Enough information is not yet available that whether bran protein behave as gluten

protein or they disturb the gluten network.

Figure 10: Variation in Protein (%) in flour from semolina overtail streams

d. Protein content in flour from Middling passages

The protein amount in middling streams varied widely. The minimum quantity of protein

as 9.6% was recorded in R1A stage/streams while maximum was found as 11.4% in C7B.

10.40

10.30

10.20

10.00


10.40

10.15

11.05

11.30

C1B C4 C5 C6

46

Figure 11: Distribution of protein (%) in flour from middling streams.

e. Conclusion

Consistency in protein distribution was recorded in semolina streams. Our results

confirmed the earlier findings that streams rich in ash contents were found also to have

high amount of protein. Protein and ash showed close association in compositional

distribution of protein in the wheat kernel.

3.1.3.1.3. Ash

Both the components of flour i.e. ash and proteins act as a deciding factors of flour quality

for biscuit, cake, crackers etc. The lower ash and protein content are the indicators for

soft quality of flour; hard and durum flours consist more protein. The increased amount

of protein and ash in the flour produces cookies of hard texture, reduced diameter and

darker in color.

a. Ash content in flour from Break passages

Constant increase in ash content was observed in streams obtained from break rolls

however the rate of increase was maximum in streams from 4th to 5th rolls. Minimum ash

content 0.63% recorded in 1st break whereas maximum ash % i.e. 1.38% was recorded in

5th break with a difference of 0.75%. The results showed that ash was found to be

increasing with further grinding of wheat, suggesting wheat bran was gradually being

finely ground and mixed in flour. Geng et al (2012) have also reported the ash enrichment

of flour in break streams in later phases of milling.

10.65

11.15

9.60

11.30 11.40

10.75


Protein (%) in Flour Streams from Middling

47

Figure 12: Variation in ash (%) in flour from break rolls streams

b. Ash content in flour from Semolina passages

The amount of ash produced in semolina streams was found to be reduced. As the flour

passed through the purifiers, the bran was completely eliminated which was a rich source

of ash. The importance of measuring ash diversity is essential to assess the changes of

flour in quality during disintegration or the streams collected and its impact on spread

ratio of the cookies (Gaines et al, 1988).

Figure 13: Variation in Ash (%) in flour from semolina streams

c. Ash content in flour from Semolina Overtail passages

The ash obtained in the streams C1B, C4, C5 and C6, ranged from 0.35% to 0.7% which

were collected immediately after purifier stage and named as overtail (as they retained

on the sieves of purifier). The lower ash quantity in C1B and C4 was due to the removal

of bran flakes from sieves and less opportunity of bran to be finely ground by the set of

0.63 0.65

0.94

1.08

1.38


0.41

0.35

0.39

0.42


48

rollers in initial stage. In later phases finely ground bran was mixed with flour thus

increased the ash value.

Figure 14: Ash (%) in flour Streams from semolina overtail streams

d. Ash content in flour from Middling passages

The ash contents present in streams in middling varied from 0.37% to 0.87% with a

difference of 0.50%. The flour consisting high ash content is usually directed towards Atta

(a low refined type of flour used for Chapatti making in Pakistan), whereas low ash flour

is mixed with flour used for biscuit production. The flour from middling streams showed

very varied ash distribution as also shown in the case of moisture distribution.

Figure 15: Variation in ash (%) in flour from middling streams

0.35

0.44

0.660.70

C1B C4 C5 C6

0.49

0.62

0.37

0.78

0.87

0.65


49

e. Conclusion

The flour consisting low ash were produced from all the streams in middling and

semolina. Wide variation was noticed in all type of streams. The lower ash content in

flour streams from middling and semolina showed that they should be included more in

blending for biscuit making and ratio should be adjusted accordingly.

3.1.3.1.4. Gluten index

GI is a parameter in flour that predicts the dough strength based on network making

ability during dough formation. High GI reflects strong network of gluten proteins present

in the flour. The flour suitable for biscuit production should make weak gluten network

i.e. low GI. (Madugiri et al 2008) as dough required to be soft in nature.

a. Gluten Index in flour from Break passages

High value of GI was observed that varied from 88 to 96, strong gluten network is

expected from all the break roller streams. However a constant increase or decrease in

GI was not observed.

Figure 16: Variation in gluten Index (%) in flour from break streams

b. Gluten Index in flour from Semolina passages

The semolina flour showed slightly less GI values from 83 to 95. It was an indication that

purified flour was producing slightly less glutenins as compared to gliadins.

93

88

93

96 96


50

Figure 17: Variation in gluten index (%) in flour from semolina streams.

c. Gluten Index in flour from Semolina overtail passages

Minimum GI achieved in C4 passages, the reason is unknown but it may be attributed to

low ash content.

Figure 18: Variation in gluten index (%) in flour from semolina overtail streams.

d. Gluten Index in flour from Middling passages

Variation showed decrease in gluten index in flour streams from 93 to 84, almost a

constant decline.

87

95

83

94


94

70

9288

C1B C4 C5 C6

51

Figure 19: Variation in gluten index (%) in flour from middling streams.

e. Conclusion.

Slight higher GI was observed in all the streams however, the streams also had low ash

content, it was looked that the medium GI and low ash complement each other and the

flour was suitable for biscuit making.

3.1.3.1.5. Dry Gluten

Generally flour is categorized on the basis of dry gluten content. Higher dry gluten values

referring to hard flour are required for pasta, pizza and bread making whereas low dry

gluten values is desired for biscuit, wafers and cakes.

a. Dry gluten in flour from Break passages

The dry gluten varying from 6.9% to 10.03% was obtained in 5 break rolls. However the

quantity of dry gluten rose till the streams obtained from 3rd break then it dropped in the

4th and 5th break. The rise and fall in the quantity of dry gluten probably was related to

the design and number of the grooves present in each roller.

93

92

9091

88

84


52

Figure 20: Variation in dry gluten (%) in flour from break rolls streams

b. Dry gluten in flour from Semolina passages

The dry gluten recorded in semolina varied from 7.3% to 8.8% with a difference of 1.5%.

No significant difference or relation was observed. The difference in gluten content in

different streams might be linked with the gap between the two rollers and its differential

speed.

Figure 21: Variation in dry gluten (%) in flour from semolina streams

c. Dry gluten in flour from Semolina overtail passages

The dry gluten in flour was recorded the higher values varied from 8.7% to 9.4% with a

maximum difference of 0.7%. There are many number of factors that may influence the

inclusion of gluten in flour (endosperm) such as the distance between the roller, design

etc.

7.43

9.6010.03

7.20 6.90


7.90

8.80 8.60

7.30


53

Figure 22: Variation in dry gluten (%) in flour from semolina overtail streams.

d. Dry gluten in flour from Middling passages

All variety of flours consisting variable quantity of DG obtained from 6 middling streams

showed different percentage of dry gluten in initial, middle and the last streams. The

quantity of DG varied from 7.00% to 9.8% with a difference of 1.8%.

Figure 23: Variation in dry gluten (%) in flour from middling streams.

e. Conclusion

The quantity of dry glutens obtained from various streams varied widely as recorded in

flour collection. A strong relation of ash with dry gluten was observed in break roll

streams as the values of ash as well as dry gluten were found to be the highest. It may be

attributed to the fact that minerals generally are bound to the proteins. It may be pointed

out here that how higher values of dry gluten are helpful to categories flour as weak,

strong or durum.

8.70

9.25

9.40

9.20

C1B C4 C5 C6

8.35 8.40

7.00

9.60 9.80

8.50


54

3.1.3.1.6. Wet Gluten

The wet gluten is similar in parameter to DG that is used to identify the flour type,

strength based on the gluten proteins network. Most of the flour standards are based on

gluten contents where gluten is referred as wet gluten. It also predicts the water

absorption capabilities of gluten which is linked to end quality of most of the baked

products. The water absorption value obtained from Farinograph represents the water

retained by all the hydrophilic components present in flour including the water held by

the gluten proteins.

There was no significant variations in values as observed in analyzing various streams.

Figure 24: Variation wet gluten (%) in flour streams from 18.8 to 28.78%.

Figure 25: Showing minor variation in wet gluten (%) in flour streams from 20.70 to

26.1

22.02

28.27 28.78

20.4618.80


Wet Gluten (%) in Flour Streams from Break Rolls

23.7526.10 25.95

20.70


Wet Gluten (%) in Flour Streams from Semolina

55

Figure 26: Variation in wet gluten (%) in flour streams from 25.75 to 29.23

Figure 27: Wet gluten (%) in Flour streams from middling

3.1.3.1.7. Particle size distribution

Particle size of flour plays vital role in determining the water absorption, damaged starch

production, and evaluation of the texture of the biscuit.

a. Particle size in flour from Break passages

The present milling design produced flour of particle size 132 micron from 1st and 2nd

break, whereas the flour from 3rd, 4th and 5th break maintained as 180 micron. The

retention of flour particles at 160 micron sieve including the sieve 1st and 2nd was almost

nil, whereas the particle size of the flour from 3rd, 4th, and 5th break rolls was increasing.

At 125 micron, highest retention was observed in 4th break. Whereas lowest retention

was observed in 1st break. Overall, very fine particle of flour was produced by 1st and 2nd

break, whereas 4th break produced flour of coarse particle.

25.75

28.9529.23

27.33

C1B C4 C5 C6

Wet Gluten (%) in Flour Streams from Semolina overtail

25.58 25.53

21.50

28.5030.05

26.08


56

Figure 28: Showing increase in % retention at 160 µm sieve of flour streams from

break rolls

Figure 29: % Retention at 125 µm sieve of Flour streams from break rolls

Figure 30: % through from 125 µm sieve of Flour streams from break rolls

0.1 0.7

33.0

38.8

46.8


6.7

13.3

37.7

43.6

30.1


93.286.0

29.3

17.623.1


57

b. Particle size in flour from Semolina passages,

A fine semolina passage C2C, 180 micron sieve was placed due to which high relation at

160 micron observed. C2C produced coarse particle flour whereas C3A, C2A/B produced

very fine flour.

Figure 31: % Retention at 160 µm sieve of flour streams from semolina showing

retention 0.1 to 9.1%

Figure 32: % of flour streams retained at 125 µm sieve from 5.0 to 72.8% in semolina

passages

2.6

9.1

0.2 0.1


6.9

72.8

25.1

5.0


58

Figure 33: % of flour streams from semolina from 125 µm sieve.

c. Particle size in flour from Semolina overtail passages

Fine flour retained at 125 micron in C5 and C6 is to be higher than the flour that passed

through the sieve. Whereas a small amount of coarser flour was retained in C1b and C4.

Figure 34: % of Flour Streams from 0.1 to 4 retained at 160 µm sieve in semolina

overtail passages

90.5

18.1

74.8

94.9


4.0

0.1 0.2 0.1

C1B C4 C5 C6

59

Figure 35: % Retention at 125 µm sieve of flour streams from semolina overtail

Figure 36: % through from 125 µm sieve of flour streams from semolina overtail

d. Particle size in flour from Middling passages

The streams R1A, C7A, C7B and C8 produced fine particle size flour whereas DD1

produced coarse flour.

54.7

43.1

7.9

20.9

C1B C4 C5 C6

41.3

56.9

92.0

79.0

C1B C4 C5 C6

0.6

12.8

0.80.1 0.1 0.3


60



Figure 39: % through from 125 µm sieve of flour streams from middling

e. Conclusion

Different fractions of flour consisting different particle size are received during milling by

setting the distance between the rollers and using sieves of different sizes

As per customer requirement the flour of a particular particle size may be obtained by

applying modification in milling techniques and using specified blending techniques to

produce the composite flour.

18.5

29.4

20.8

10.9

19.0

12.8


81.0

57.8

78.4

89.0

80.986.9


61

3.1.3.2. Study of the Dough Rheology of Flour – Farinograph Analysis

Dough behavior during mixing is determined by using variety of chemical and

instrumental methods, Farinograph is one of them. Following parameters from

Farinograph were helpful in understanding the dough development process.

3.1.3.2.1. FQN

Farinograph quality number is known to predict overall behavior of flour, higher values

represents the hard flour. The Farinograph quality number is directly linked to the

dimensional properties of biscuit such as the high FQN will give low spread ratio of the

biscuit.

a. FQN in flour from Break rolls milling passages

Very high FQN was reported in streams from break roll except on 1st break where only 23

FQN was received. The streams from other break passages showed and confirmed the

production of hard flour and provided strong dough making ability of flour.

Figure 40: FQN in flour from break streams

b. FQN in flour from Semolina passages

Almost every stream showed softness in dough except the fine semolina C2C. FQN values

i.e. 25, 26 and 27 were reported in C1A, C2A/B and C3A respectively. It stated that

semolina streams produced flour of low FQN in comparison with flour from break rolls.

Low FQN in semolina streams suggesting that softest flour was achieved in pure

23

155 154

122110


62

endosperm part of the wheat grain or might be low ash content contributed to the

softness with respect to the FQN value.

Figure 41: FQN in Flour from semolina streams

c. FQN in flour from Semolina overtail passages

Very low FQN in C1B was reported. It is a first stream of semolina overtail of purifier. Rest

of the streams were produced middle range of FQN around 67 to 74.

Figure 42: FQN in Flour rom semolina overtail streams

d. FQN in flour from Middling passages

Low (22) to high (100) FQN were observed in middling passages. Half of streams

contained FQN in lower side whereas FQN was increased as grinding proceeded.

25

98

27 26


9

67

74 74

C1B C4 C5 C6

63

Figure 43: FQN in flour from middling streams

e. Conclusion:

High FQN flour was produced in break stages whereas low FQN was produced by

semolina streams.

3.1.3.2.2. Water absorption

It is an important parameter in dough making process suggesting changes in flour

behavior. High WA% is required in pasta and bread making process whereas low WA% is

the required for biscuit and cake. The WA is closely associated to ash and damaged starch

present in the flour.

a. Water absorption in flour from Break rolls passages

Water absorption was increasing as wheat was further ground. Very low water

absorption was the result of having low content of damaged starch, protein and ash

content in the flour streams. The WA was gradually increased in 5th break from 53.2% to

66.6%. However a constant increase in water absorption was observed.

27 2922

88

100

47


64

Figure 44: Water absorption % in Flour from break streams

b. Water absorption in flour from Semolina passages

The percent of water absorption was ranged from 58.6% to 69%, while the lowest value

in stream of break roll which was 53.2% while in semolina streams it was recorded as

62.2% for the first stage passage (coarse semolina). In fine semolina passages, WA was

reported as 58.6% which then increased up to 67% in further streams. It had clearly

shown that in further processing, flour was getting damaged and would take extra water

in recipe.

Figure 45: Water absorption % in Flour from semolina streams

c. Water absorption in flour from Semolina overtail passages

The stream C1B had low WA as 57% whereas all the overtail streams of semolina had

high WA ranged from 64.8% to 68.3%. The water absorption increased slightly from the

53.256.0

60.162.6

66.6


62.2

58.6

62.4

67.0


65

water absorption in break roll and semolina streams, which showed highest values as

66.6% and 67% respectively.

Figure 46: Water absorption % in flour from semolina overtail streams

d. Water absorption in flour from Middling passages

The amount of WA fluctuated within the range of 59.2% to 67.9%. The streams in the

initial stage had low water absorption, however WA raised in the central streams and last

i.e. C8, it again dropped to 59.2%.

Figure 47: Water Absorption % in flour from middling streams

e. Conclusion

The highest and lowest value of WA in streams from break roll, semolina, semolina

overtail and middling recorded as 53.2-66.6%, 58.6-67%, 57-68.3% and 59.2-67.9 %

57.0

68.3

66.064.8

C1B C4 C5 C6

Water Absorption % in Flour Streams from Semolina overtail

60.4

59.2

67.066.1

67.9

63.2


66

respectively showed an overall increase of 6% from lowest value while an increase of 1-

2% in highest absorption value.

3.1.3.2.3. Dough development time

The dough development time depends on the nature of hardness of the flour, especially

the amount of hydrophilic components of flour. The hydrophilic biopolymers present in

flour include starch bran, proteins and pentosan. The hydration capacity and hydration

rate of the flour are associated with these components. DDT is an indicator that how

much time is required for a flour to form a desired dough. Higher DDT represents the

hard flours and need more water to be absorbed.

a. Dough Development time in flour from Break Rolls passages

Initial two break rolls streams produced low DDT whereas following three streams

required longer time for dough to develop DDT. It might be attributed due to the

inclusion of bran that showed high water absorption.

Figure 48: DDT (min) in flour from break rolls streams

b. Dough Development time in flour from Semolina

The low DDT of 1.5 to 1.9 min was reported in semolina streams. Dough would be

developed early if flour from these streams are to be utilized in biscuit making and saving

of energy required in mixing i.e. cost involved will be reduced.

1.3

2.5

7.1

5.5 5.7


67

Figure 49: DDT (min) in flour from semolina streams

c. Dough Development time in flour from Semolina overtail passages

The C5 passage produced high DDT i.e. 12.9 minutes where as others produced lower

DDT values. Reason for C5 to take longer dough mixing time might be attributed to

distance of rollers in this portion, change in sifter or other reasons for variation in particle

size. However it showed that the flour from C5 should either be recycled or mixed with

semolina or middling streams in the appropriate proportion to suit end quality and to

reduce DDT.

Figure 50: DDT (min) in flour from semolina overtail streams

d. Dough Development time in flour from Middling passages

The dough development time remained almost constant and streams were consistent in

terms of DDT recorded in middling streams. The time for development of dough was the

least i.e. only 1.5 to 1.7 minutes in middling streams.

1.5

1.7 1.7

1.9


1.7 2.0

12.9

1.9

C1B C4 C5 C6

68

Figure 51: DDT (min) in flour from middling streams

e. Conclusion

Although not very strong relationship of DDT was found with any other parameter, but

as some association has been found with ash, water absorption and particle size of the

flour, the collective values of the above parameters will reduce the mixing time.

3.1.3.2.4. Dough Stability (DST)

The strength of dough to remain stable is expressed as dough stability, it indicates that

how much a flour after conversion to dough during continuous mixing may hold its

network in native form and prevent the dough from turning to be more fluid. The high

DST represent strong dough made from hard flour. The network holding property against

mechanical shearing if gets prolonged dough will produce an optimal dough.

a. Dough Stability in flour from Break passages

Flour streams in first break produced less stable flour whereas second and third break

produced flour that made highly stable dough. Flour of medium stability was also

achieved. The dough stability was highest as 14.7 min in the 3rd break streams and lowest

1.9 min in the 1st break with a difference of 12.8 min while the average time for the dough

to remain stable was noted as approx. 9.4 min.

1.6 1.6

1.5

1.7 1.7 1.7


69

Figure 52: DST (min) in flour from break streams

b. Dough Stability in flour from Semolina passages

Very low to medium DST was achieved at this stage ranging from 0.9min to 8.6 min with

and average of 3.8 min. showing that flour needs to be mixed with flour of high DST if

long duration of mixing is required before baking.

Figure 53: DS (min) in flour from semolina streams

c. Dough Stability in flour from Semolina overtail passages

Medium DST was achieved in these streams, values varies from 5.3 min to 8.4 min. The

difference in dough stability among the four stream was less (3 min) as compared to the

stability of other streams 8.3 min.

1.9

13.614.7

9.5

7.5


1.3

8.6

4.5

0.9


70

Figure 54: DST (min) in flour from semolina overtail streams

d. Dough Stability in flour from Middling passages

The dough was found to be stable for only a short period of time i.e. for two minutes or

even less in first three streams of middling, later on it remained stable up to 7.7 minutes.

The stability time of dough varies from 1 min to approximately 8 min in various streams

of middling.

Figure 55: DST (min) in flour from middling streams

e. Conclusion

DST was decreasing as ash, particle size, protein and damaged starch were increasing in

the flour. The dough stability time is highly important in control of the process, because

of DST is more than the time required for sheeting, cutting and time taken just before

entering in the oven, than end quality of biscuits will not change throughout baking,

otherwise the last batch of biscuits will be of poor quality.

8.3

7.5

8.4

5.3

C1B C4 C5 C6

1.9 2.1

0.6

6.9

7.7

3.9


71

3.1.3.2.5. Degree of softening DoS (ICC)

Dough rheology change rapidly during mixing. The DoS after 10 minutes of mixing time

or 12 minutes give certain characteristics of dough related to end quality. It determines

the softness in dough structure that is also visible in SEM microstructure. The value of

higher DoS reflects soft dough, suitable for production of biscuit, cake etc.

a. Degree of softening in flour from Break passages

The DoS in break streams fluctuated widely and did not show any distinct relationship

and as the value range from 23.3 to 71 FU (Farinograph Unit).

Figure 56: DoS (FU) in flour from break streams

b. Degree of softening in flour from Semolina passages

The flour streams from semolina showed that dough prepared from Semolina flours

would have a softer structure than dough processed from flour stream from break roll.

The range (48 FU to 96 FU) as found in the Semolina flour. The DoS between 48 to 96 FU

is suitable for biscuit and cookie.

71.3

27.0

45.0

23.3

60.0


72

Figure 57: DoS (FU) in flour from semolina streams

c. Degree of softening in flour from Semolina overtail passages

Mid-range of DoS (47 to 69 FU) was reported in these streams. The difference of 22 FU

was quite distinct and wide, however it was less than the same difference in FU was

observed in streams from break and semolina.

Figure 58: DoS (FU) in Flour from semolina overtail streams

d. Degree of softening in flour from Middling passages

R1A was found softest among all the streams which produced DoS value as 137,

otherwise mid-range of DoS was reported in the remaining streams.

74.0

48.0

62.5

96.0


54.0

69.0

47.049.5

C1B C4 C5 C6

73

Figure 59: DoS (FU) in flour from middling streams

e. Conclusion

Summary of the Farinograph parameters, In general, flour from break rolls were found

to produce soft nature dough. The Farinograph parameters are very helpful in evaluating

the precautions to be taken during mixing to get optimal dough which behaves without

problem in processing.

3.1.3.3. Pasting Behavior of Dough – MVAG

3.1.3.3.1. Maximum hot paste viscosity/Peak viscosity (MV/PV)

Both the MV and PV values are referred in the literature for describing the maximum hot

paste viscosity, however in the present description only MV is used to avoid any

confusion. The flour having high maximum/peak viscosity tends to have high swelling

ability. They can hold high moisture under critical temperature and mechanical strength.

In general soft wheat flours show highest MV as compared to hard flours or durum. The

highest pasting viscosity indicated the high content of starch in wheat flour.

a. Peak/Max. viscosity in flour from Break passages

The MV/PV was found to be decreasing constantly as grinding further proceeded. The

MV as 996 BU was recorded as the highest value of maximum viscosity observed in the

1st break. The slight decrease in max viscosity in later stages may be due to a constant

increase in damaged starch content. The lowest MV as 814 BU was observed in the 5th

break with a difference of 182 BU.

76.0

53.0

137.0

53.0 49.0

72.5


74

Figure 60: Max. Viscosity (BU) in flour from break streams

b. Peak/Max. viscosity in flour from Semolina passages

It was observed that among the semolina streams maximum viscosities increased from

860 to 1047 BU with a difference of 187 BU although the increase was not constant and

both the fine and coarse streams showed varied value of MV.

Figure 61: Max. Viscosity (BU) in flour from semolina streams

c. Peak viscosity/Max. in flour from Semolina overtail passages

The C4 passage produced the least maximum viscosity of 875 BU, whereas high viscosities

were recorded in rest of the passages. The highest value recorded as 1047 BU was

observed in only either the streams Semolina or Semolina overtail.

996.0947.0 918.0

867.3814.0


958.01047.0 1031.0

860.0


75

Figure 62: Max. Viscosity (BU) in flour from semolina overtail streams

d. Peak/Max. viscosity in flour from Middling passages

R1A had the low maximum/peak viscosity, whereas high viscosities were achieved by rest

of the streams. The lower value of MV was recorded in 5th break as 814 BU, in semolina

as 860 BU, in semolina overtail as 875 BU and in middling streams as 848 BU.

Figure 63: Max. Viscosity (BU) in flour from middling streams

3.1.3.3.2. Break Down viscosity (BDV)

The BDV is correlated to the trough viscosity which is also referred as the minimum hot

paste viscosity. The difference between the maximum hot paste viscosity (MV or PV) and

the minimum hot paste viscosity (trough viscosity) is referred as BDV and is calculated

from a pasting curve. The starch granule in the grains get disrupt during holding period

of the viscosity test because the starch is subjected to mechanical shear stress , amylose

to leach out and re arrange itself. This period is closely associated to BDV. Various

1047.0

875.0

1011.5993.5

C1B C4 C5 C6

989.51032.5

848.0

966.0 969.0 959.5


76

starches behave differently to be stable at this high temperature and shear and are

related to dough spreading during baking. The swelling of starch granules during baking

or heating is related to high value of BDV and MV. Both MV and BDV are associated with

the end quality i.e. puffing and spreading.

a. Break Down viscosity in flour from Break passages

Similarly like MV, BV was also found to be decreasing in break roll streams from 1st break

to the 5th break roll stream. The highest BV was recorded in 1st break as 355.7 BU whereas

lowest recorded in the 5th break as 295 BU, with a difference of 60 BU.

Figure 64: BD Viscosity (BU) in flour from break streams

b. Break Down viscosity in flour from Semolina passages

The breakdown or the BDV values reported in semolina stage varied from 326 BU to

383.5BU with a difference of 59 BU. So maximum value of 355BU from the first break roll

streams was almost maintained in the flour stream from Semolina. The highest value of

385.5 BU in Fine C2A/B was recorded against the lowest value of 326 BU.

355.7335.7

353.3324.5

295.0


77

Figure 65: BD Viscosity (BU) in flour from semolina streams

c. Break Down viscosity in flour from Overtail passages

The breakdown viscosity record showed a difference of 57.5BU. Lowest BD was reported

in C4 i.e. 186BU. Highest reported in C5. The difference in BDV in the semolina overtail

stream was recorded as the highest 204.5BU. This property may be attributed to highest

particle size of the flour.

Figure 66: BD Viscosity (BU) in flour from semolina overtail streams

d. Break Down viscosity in flour from Middling passages

High BDV was reported in all the middling stage streams with minor difference in values.

The highest BDV of 386.0 BU is obtained from Stream DD1 while the stream R1A gave the

lowest value as 308 BU, the difference of only 78 BU.

358.0

370.0

383.5

326.0


385.0

186.0

390.5 377.5

C1B C4 C5 C6

78

Figure 67: BD Viscosity (BU) in flour from middling streams

3.1.3.3.3. Setback viscosity (SV)

As the BDV is related to behavior of Starch during heating the setback viscosity is the

change in viscosity during cooling and is calculated from pasting curve obtained from

MVAG by subtracting the trough viscosity from final viscosity FV. The final viscosity

represents the viscosity at the end for the test after cooling the paste to 50 0C and holding

the paste at the temperature. The trough viscosity (not mentioned in the present

discussion but shown on pasting curve) is related to holding strength of the paste. The SV

is associated to Starch molecules especially amylose re arrangement during cooling to

form gel structure in dough. FV therefore rises during cooling due to retro gradation of

starch. If the rate of retro gradation of starch will be high, high value of SV will be

recorded. The low SV indicates soft flour.

a. Setback viscosity in flour from Break passages

An increasing trend of SV was observed. 402.3 to 568.7 BU was the range observed in

break streams. Highest viscosity was recorded in 1st break. The first break stream had the

highest SBV as 568.7 BU as compared to the lowest SBV of 402.3 BU from the 4th beak

stream with a difference of 166.4 BU.

369.5386.0

308.0

378.0 383.0368.0


79

Figure 68: SB Viscosity (BU) in flour from break streams

b. Setback viscosity in flour from Semolina passages

The streams from Semolina did not show significant difference in SB values as compared

to the values form Break rolls. The mid-range of SB was observed in the semolina stage.

Figure 69: SB Viscosity (BU) in flour from semolina streams

c. Setback viscosity in flour from Overtail passages

A great variation in SBV was observed in the streams from Semolina overtail as 298.5 BU

as the minimum setback viscosity recorded in semolina overtail of C4. While the highest

SB viscosity 578 BU was observed in Fine C2C with a difference of 268.5 BU.

568.7531.7

508.0

402.3

452.0


496.0

578.0537.0

467.0


80

Figure 70: SB Viscosity (BU) in flour from semolina overtail streams

d. Setback viscosity in flour from Middling passages

The minimum SB viscosity as 465 BU whereas high SB viscosity as 547.5 BU were recorded

in middling stage and a difference of only 82.5 BU.

Figure 71: SB Viscosity (BU) in flour from middling streams

e. Conclusion:

The various viscosities i.e. MV, BDV and SBV indicated pasting properties (from the

pasting curve) clearly of the behavior of flour during heating and cooling process. The

study of the pasting curve or more elaborating the viscosities value (MV, BDV, and SBV)

would be very helpful in selection of streams and their inclusion for a particular bakery

product.

567.0

298.5

530.0 512.5

C1B C4 C5 C6

531.5

547.5

465.0

478.0

506.0

521.0


81

3.1.3.4. Solvent Retention Capacity of Flour Streams

The SRC test is a sum of flour test i.e. SC-SRC, Water SRC, Su-SRC and LA-SRC, indicating

the presence of different components of wheat flour.

3.1.3.4.1. Sodium Carbonate Solvent Retention Capacity - SC-SRC

The SC-SRC predicts the damaged starch level in flour. The higher SC-SRC value indicates

the higher damaged starch contents in flour.

a. SC-SRC in flour from Break passages

It was noted that sodium Carbonate SRC was increasing with the grinding proceeded.

High SC-SRC in the 5th break represented the milling pressure on the grain to produce

flour. Very low i.e. 70% SC-SRC provided by 1st break. It was clearly shown that milling

rollers were constantly grinding the grains to produce more of the damaging starch. The

5th break roll stream produced the highest amount of damaged starch as 97% while the

first break had the lowest value of 70.47% with a difference of 16.6%

Figure 72: SC-SRC flour from break streams

b. SC-SRC in flour from Semolina passages

The high amount of damaged starch (106.93% and 130.37%) was reported in coarse C1A

and fine C3A, respectively whereas fine C2C and fine C2A/B produced mid-range of

damaged starch. Due to coarse particle size distribution in flour as seen in C2C, less

70.47 72.7279.08

83.24

97.07


82

damaged starch was produced in the stream C2C. A different of 43.5% in the percent of

damaged starch was recorded in Semolina streams.

Figure 73: SC-SRC in flour from semolina streams

c. SC-SRC in flour from Semolina Overtail passages

A significant difference in the amount of damaged starch among the four break roll

streams was observed and mid rang of SC-SRC was reported (84.88% to 113.53%). Since

these streams were the overtail of Semolina, thus to have high milling exposure which

ultimately produced high damaged starch.

Figure 74: SC-SRC in flour from semolina overtail streams

106.93

86.92

99.61

130.37


84.88

113.53

98.7693.72

C1B C4 C5 C6

83

d. SC-SRC in flour from Middling passages

Similarly line Semolina overtail the streams from middling produced mid to high SC-SRC

Values i.e. 84.84 to 138.7% and a difference in the percentage of damaged starch

recorded was found to be 53.83%.

Figure 75: SC-SRC in flour from middling streams

e. Conclusion

Those streams which were gone through many grinding rolls, producing damaged starch.

In break stages, flour were having less damaged starch as compare to middling and

semolina overtail. Secondly the qualitative difference in the percentage of damaged

among the four categories i.e. break, semolina, semolina overtail and middling that

indicated collectively the increase in damaged starch in the streams

3.1.3.4.2. Water SRC

Gluten, damaged starch, pentosans etc. contributes to the water absorption individually

in flour while W-SRC is a measurement collective capacity of water absorption of the flour

and shows how much these molecules can uphold moisture during mixing. W-SRC value

i.e. the swelling power of flour is directly linked to dimensional and textural properties of

the biscuit.

88.92 84.87

138.70

100.47 101.20 99.98


84

a. Water SRC in flour form Break passages

Minimum value of W-SRC was found in 1st Break i.e. 61.7% whereas highest value was

reported in 3rd break i.e. 93.77%, a difference of 32.07% was observed. No clear relation

of W-SRC was found with milling mechanics or any other parameters of flour analysis.

Figure 76: W-SRC flour from break streams

b. Water SRC in flour form Semolina passages

Similarly like break streams, in semolina streams no clear relation of W-SRC was

determined with milling parameters. However 71.12% to 154.87% is the range among

the W-SRC values achieved in these passages and a difference of 83.75% was recorded in

the water absorption capacity of the streams in Semolina.

Figure 77: W-SRC in flour from semolina streams

61.70 63.00

93.77

75.06

83.34


128.71

71.12 73.98

154.87


85

c. Water SRC in flour form Semolina Overtail passages

Higher to lower W-SRC was reported in these streams. C4 produced the highest water

holding capacity while C6 absorbed only 77.03% water with a difference of 48% W-SRC.

Figure 78: W-SRC in flour from semolina overtail streams

d. Water SRC in flour form Middling passages

Overall lower value of W-SRC was produced in the middling stage. However, minimum

difference of 26.7% was recorded among the flour stream DD1 having the lowest value

of W-SRC (69.89%) and the last stream C8 (96.6%). The water absorption capacity of the

6 streams of middling remained similar to each other and any stream may be selected for

blending if W-SRC is taken as a parameter for the quality evaluation.

Figure 79: W-SRC in 6 flour from middling streams

109.56

126.20

94.70

77.03

C1B C4 C5 C6

75.0269.89

91.1081.93 82.79

96.60


86

e. Conclusion

Although no significant relation of W-SRC was reported with milling streams. However, it

may be considered that difference in variation of W-SRC values is highest in the flour

streams from Semolina and least among the streams for middling. Great skill will be

required in selection of streams for blending to get the desired optimal composite flour

for biscuit making.

3.1.3.4.3. Sucrose SRC (Su-SRC)

The pentosans and gliadin contents of flour are extracted in sucrose solution. Gliadin

proteins are single chain, low molecular weight proteins which either has single or no

intra disulphide bridges as compared to glutenins having multiple disulphide bridges

making them polymeric proteins of higher molecular weight. Gliadin control viscosity of

the dough and viscoelastic properties are due to both types of the gluten proteins i.e.

gliading and glutamine.

a. Sucrose SRC in flour from Break passages

Mixed trend was observed in Su-SRC values among the flour streams form the break rolls.

On third break stream minimum value of 82.67% was found that suggested that at third

break low amount of pentosanes and gliadin transferred into flour. Whereas 5th break

produced flour of highest S-SRC i.e. 119.62%. The difference of 26.95% was noted.

Figure 80: Su-SRC flour from break streams

91.7197.85

82.67

109.01119.62


87

b. Sucrose SRC in flour from Semolina passages

In Coarse C1A and Fine C3A, S-SRC was found to be the lowest i.e. 78.88%, 88.20% and

highest and 108.65%, 110.48% respectively. The middle passages of Semolina streams

were carrying flour of high S-SRC. Results reflecting that coarse and last passage of fine

semolina has less pentosans and gliadin content.

Figure 81: Su-SRC in flour from semolina streams

c. Sucrose SRC in flour from Semolina Overtail Passages

Flour streams received from C1B passage, had very low Su-SRC and as grinding proceeded

the value increased constantly. 67.12% to 109.9% S-SRC reported in overtail semolina

passages. A difference of 42.78% was observed. The S-SRC values were found to be

increasing constantly and steadily.

Figure 82: Su-SRC in flour from semolina overtail streams

78.22

108.65 110.48

88.20


67.12

83.32

97.90

109.91

C1B C4 C5 C6

88

d. Sucrose SRC in flour from Middling passages

Mid to high level of Su-SRC reported in these streams, R1A and C7B are having very high

Su-SRC values 154.5% to 171.42 %. A zig zag shaped variation was observed among the

flour from six streams from middling, 97.97% as the lowest while 171.42% as the highest

value. A vast difference of 73.45% was recorded.

Figure 83: Su-SRC in flour from middling streams

e. Conclusion:

In general it is observed that the passages which are obtained after going through many

rollers, usually produced flour of high Su-SRC. Dough prepared from such flours will show

high viscosity.

3.1.3.4.4. Lactic Acid Solvent Retention Capacity - LA SRC

LASRC is more closely related to the concentration of high molecular weight glutenins

that are positively related to bread loaf volume (LV). However, they are inversely related

to biscuit dimensional properties. It has been observed earlier that higher values of

glutinins produce biscuit of reduced diameter in view of the high elasticity of dough

(Wieser and Kieffer, 2001, Wieser et al, 2003).

a. LA-SRC in flour form Break Passages

A range of 72% to 94% was attained during break stage. On 1st break minimum value of

72.15% achieved whereas higher value of 94.13% was achieved in 5th break. A difference

111.31101.81

154.50

112.46

171.42

97.97


89

in first LA-SRC value i.e. first and 5th streams was recorded as 21.98%. LA-SRC was

increased with grinding proceeded further.

Figure 84: LA-SRC (%) in flour from break streams

b. LA-SRC in flour form Semolina passages

In coarse semolina flour stream C1A, LA-SRC was found on higher side. Whereas in fine

semolina flour streams LA – SRC was increased with further grinding. Highest LA-SRC as

101.94% and 97.03% was reported in from last semolina streams. Coarse – C1A and Fine

– C3A were the streams which produced flour of higher LA-SRC value that would produce

biscuits of increased diameter. The lowest LA-SRC value was recorded in fine C2C stream.

Figure 85: LA-SRC in flour from semolina streams

72.15 74.39

85.7289.68

94.13


97.03

78.04

90.25101.94


LA-SRC in Flour Streams from Semolina

90

c. LA-SRC in flour form Semolina Overtail passages

C1B was found to have low LA-SRC i.e. 78.96%, whereas the other streams form semolina

overtail produced similar values as 93.34%, 93.72% to 97% LA-SRC. The reason of C1B

was due to the less grinding exposure of stream as compared to rest streams. A

difference of 18.48% was recorded in these passages.

Figure 86: LA-SRC in flour from semolina overtail streams

d. LA-SRC in flour form Middling passages

LA-SRC varied differently in all the 6 flour streams. DD1 to have lowest LA-SRC that was

78.39%. In middling streams and highest value as 107% recorded with a difference of

28.6%.

Figure 87: LA-SRC in flour from middling streams

78.96

97.4493.34 93.72

C1B C4 C5 C6

85.9578.39

107.00

95.59 99.3493.14


91

e. Conclusion

In general, LA-SRC was found to have good relationship with different streams during

milling. In start of milling, LA-SRC was found in lower side. As milling proceeds further, it

increased and came to almost constant value.

The overall lactic acid SRC values in all the four streams i.e. break roll, semolina, semolina

over tail and middling were quite less as 21.98%, 23.9%, 18.46% and 28.61% respectively

indicated that the quantity of higher molecular weight proteins i.e. glutenins becomes

similar in each streams and any of the stream may be selected for blending purposes of

glutenins is taken as a parameter for evaluating flour quality.

3.1.4. Conclusion (Overall)

It was observed that each test was quite significant in evaluating the quality of flours from

different streams. The overall results showed fluctuation in values of various streams.

Such variations are significant for millers in choice of selection of stream for blending to

produce composite flour. The SRC values for composite flour for biscuit, bread, pasta etc.

have wide difference and must be considered at both the ends i.e. miller and bakers

before dispatching the flour for specified purpose.

Study has revealed that the milling is not so simple, it produce different quality of flour

from same mill type. Extensive working is required to fulfil the customer’s requirement

(quality and quantity of flour) and also a close working relationship is essential between

millers and bakers to produce the desired end quality of the product.

92

3.2. Comparative analysis of physiochemical and dough rheological

properties of break and reduction streams and its impact on the quality

of cookie.


Presently the discussion is focused to explore the impact of chemical and physical

parameters to evaluate the characteristics of 20 streams (break 6, reduction 14) related

to the behavior of viscous mass (dough) and end quality of biscuit.




3.2.2.1. Material

Soft wheat was commercially milled to flour at Garibsons Private Ltd. Port Qasim

Industrial Area, Karachi. Total 20 flour streams were collected i.e. 6 samples of break

streams and 14 samples of reduction streams for the study.

Analytical grades reagents/chemicals were used procured from the distributor of Sigma

Aldrich (Germany) in Pakistan, Labline Pvt. Ltd.

3.2.2.2. Biscuit Preparation

The dough was prepared by mixing all ingredients as per recipe mentioned in table 5. First

emulsion was prepared by mixing all the ingredients except flour in Kenwood Mixer, UK

at a speed of 40 rpm for 1 min, and then flour was added and mixed at 25 rpm for 1:30

minutes to develop the dough. The dough was sheeted and cut using circular mold of 50

mm diameter. Biscuits were baked in oven (Nardi, Italy) at 205°C for 8 minutes with

heating coils fixed both at the top and the bottom ends.

93

Table 5: Recipe of cookie to evaluate the effect of different milling streams

Ingredients Quantity

(gm)

Flour 500

Sugar 150

Invert Syrup 8

Vegetable Fat 120

Skimmed Milk Powder 8

Ammonium bi Carbonate 5

Baking Powder 1

Salt 3

Lecithin 0.5

Water 62


3.2.3.1. Comparative analysis of physicochemical parameters in break and

reduction streams

The parameters of physicochemical analysis changed as the milling process proceeded.

The water in flour, quality of particles and total proteins changed, and moisture was

reduced from 14.62% (B streams) to 12.43% (R streams). The decrease in moisture is due

to two reasons (1) the surface area of flour particle was increased thus evaporation was

more. (2) Secondly mechanical heat was generated as milling continued. The particles

were getting finer and finer a the milling process proceeded, larger particles of 125

micron or above contributed to 42.25% of the total break streams, however only 13.22%

of the particles of this size were produced in break streams resulting in production of

more refined flour in reduction stream than the break stream.

94

Figure 88: Moisture, protein, particle size, bottom and damaged starch content of Break

and Reduction passages.

It was demonstrated that damaged starch will increase with reduction in particle, size

and decrease in moisture level that is why wheat tempering is necessary if fine particle

size of flour is desired.

3.2.3.2. SRC analysis

The Na2CO3 absorption is less in B streams (86.23%) than in R-Streams as 103.86%, this

indicated indirectly the volume during swelling and is a partial measure of DS. Various

streams produced different amount of DS (Damaged Starch) that clearly shows the need

of great skill required in blending the streams to produce the optimal flour (Ali et al,

2014).

Sucrose SRC which represents the presence of pentosans and gliadins and was not very

significantly correlated in the passages. The pentosans content of flour may vary in milling

streams. Pentosans mainly the arabinoxylans (AX) are the integral part of bran are found

in larger amount in starch tailing because of inclusion of bran that causes an increase in

dough density and viscosity affecting the end quality of biscuits. The dough absorbs more

water and biscuits become heavier, reduced in size and of tough texture.

14.6210.65

42.25

57.23

17.8812.43 10.72

13.22

86.52

23.36

Moisture (%) Protein % 125 µm Bottom Damaged Starch(UCD)

Break Streams Reduction Streams

95

Lactic acid absorption was found low in B streams versus R streams which is associated

to the polymeric part of gluten i.e. glutenin. As already discussed (Liu et al, 2015) it

represents the linkages between gliandins and glutenins i.e. HMW proteins are increased

during milling process represented by the Lactic acid solvent retention capacity test and

WA (water absorption) test by Farinograph. All the flour streams values of SRC test

increased during size reduction i.e. in reduction streams.

Figure 89: Variation in SRCs in two types of milling streams


The results of comparative analysis results from Farinograph for B and R streams were

reported in fig. 90. Farinograph Quality Number (FQN) is a parameter associated with

overall dough strength that remained almost constant. Water absorption capacity of

reduction stream was higher being 64.86% as compared to the WA capacity of break

passages (56.25%). Flour functionality in product making is not depended only on the

presence of water loving pioplymers but at the same time it also counts that how much

water is added and also the amount of other ingredients including sugar, sugar syrup in

pre salt dough and many other additives. The issues faced by the baking industries such

as the heavy weight, size, density, appearance (shape, color, surface hair lines) may be

solved by introducing appropriate milling and blending (Rogers et al, 1993).

86.23

74.95

104.32

80.00

103.86

92.73

111.29

94.68

Sodium Carbonate Water Sucrose Lactic acid


96

Dough development time was increased in reduction stage that was because of the

increase in Lactic acid SRC (more HMW gluteneins). Large quantity of HMW-gltuenins

are responsible for increased values of water absorption, dough development time and

L-SRC making dough hard and resistant as shown by the stable dough. Dough Stability

in R-streams (4.5min) represented increased values than in B streams (4.25 min). The

flour streams obtained from B-Streams have more DoS as 89.00FU against the DoS values

from R streams (68.93 BU). Flour from break streams is preferred for biscuit making.

The flour components determine the behavior of dough in processing which change

according to seasonal changes. Water stress during dry weather (drought) affect the

weight of grain, crude protein and its nutritional quality (Noorka et al, 2009 and Ahmad

et al, 1999).

Figure 90: Farinograph Analysis of milling streams


Higher Gelatinization temperature was found in break streams 59.97 0C as compared to

reduction streams (89.32 0C). Due to high damaged starch contents in the reduction

streams because gelatinization took place at high temperature. Similarly like

gelatinization temperature, max viscosity was higher in reduction streams 965.5 BU as

compared to break streams 733.33 BU. High damaged starch production and inclusion of

48.83

504.83

56.25

3.15 4.23

89.00

52.86

496.14

64.86

3.31 4.50

68.93

FQN Consistency WA(%) DDT (min) DS (min) DoS (ICC)


97

pentosans in break streams were responsible for increase in peak viscosity. No significant

impact was evident in breakdown viscosity between these two types of streams. Higher

setback viscosity 510.86BU than the break streams were observed in reduction streams

because the amylose and amylopectin molecules are separated and other flour

molecules are reduced so they rejoin each other easily to raise the viscosity. Amylose

amylose reunion i.e. retrogradation of starch takes place to make the dough more

viscous. Flour from these streams will produce tough textured biscuit.

Figure 91: Milling streams on Visco-amylo-graph Parameters

3.2.3.5. Glutomatic Parameters

Gluten index was found higher in break streams as 95.67% as compared to reduction

streams i.e. 87.36%. In reduction streams most purified flour was extracted for final

product thus showed higher gluten value 8.71%. In break stage, low gluten content was

achieved as 6.87%. Due to inclusion of bran in later stages of break streams, overall gluten

content in flour were changed. Dry gluten and wet gluten showed similar values because

only water was evaporated during drying otherwise the protein content of flour and the

dough were same.

59.97

733.33

351.83380.17

89.32

965.50

367.43

510.86

Gelatinization Temp.°C Max Viscosity (BU) Breakdown (BU) Setback (BU)


98

Figure 92: Milling streams on Glutomatic Parameters

3.2.3.6. End quality evaluation

Previously investigated (Charun et al, 2000) that showed the correlation of

physical/chemical parameters of the flour from two different set of streams to dough

rheology and the end quality of biscuits. Some correlation between the cookies factors

(diameter/thickness) and water absorption capacities of the flours from different type of

streams (break and reduction) was observed and reported in table 6.

The 1st break was found to consist less WA than in two reduction roll i.e. 7 and 11, which

produced cookies of reduced diameter and high in thickness

The study is confirming that blending of streams must be conducted after going through

carefully the physicochemical characteristics of flour from various streams to get the

desired product.

95.67

6.87

20.08

87.36

8.71

26.46

Gluten Index Dry Gluten Wet Gluten


99

Table 6: End Quality Analysis

Sample

Name

Water

Absorption Diameter Thickness

Cookie

Factor

BR – 1 50 49.5 6.1 8.11

RR – 7 67.9 47.1 6.3 7.48

RR – 11 59.5 48.3 6.2 7.79

3.2.4. Conclusion

The milling procedure involves in the development of various flour types like BR and RR

differing in their chemical composition which predicts the dimensional qualities of biscuit

as described in this study. Further, another important technical procedure of blending

the streams which needs qualified personals who can understand and assess constant

changes occurring in the composition of streams as the milling proceeds. The

characteristics related to biscuit depend on the presence of certain components, i.e. their

quality generated by including some particular type of flour due to blending that modified

the chemical properties of streams taken in suitable proportion.

The studies have emphasized the need of strong and solid coordination, relationship and

collaboration among farmers, flour producers (millers) and manufacturers (bakers) to

produce the optimal wheat to get the required quality of flour streams. Actually the

baked product manufacturer is to convey the message to millers about the characteristic

of flour they need for processing their products.

100

4. CAHPTER: SOLUTION OF INDUSTRIAL PROBLEM

4.1. To study wheat available in Pakistan suitable for soft product.

Identification of optimum level of damaged starch along with other

physicochemical properties for the soft dough.


Wheat is not well categorized in Pakistan with respect to its end use i.e. for biscuits,

cookies, cakes, breads and pasta etc. Usually, the end users of flour like baking industries

face many difficulties in getting suitable quality of the flour for production of their

products. Soft dough products are very critical in handling, numerous problem trouble

shooting are experienced if flour quality is not up to the mark with results that industries

have no options but to reject the flour supply.

The present study is based on to identify best wheat variety for production of cookies

and to further evaluate flour quality to pick the critical parameter which is actually being

neglected in cookies production.




4.1.2.1. Material used in the study of wheat variety

All local and imported flour suppliers of EBM were included in this study. Study was

carried out for the period from October 14 to June 15.

1. Garibsons Pvt Ltd, Karachi, Sindh, 2. Masoom Flour Mill, Karachi, Sindh, 3. Qandhari

flour mill, Karachi Sind, 4 Matiari Roller flour mill, Matiari, Sindh and imported source

Nowrangroy, India were selected for flour analysis and its impact on processing i.e. line

behavior, whereas only the wheat samples provided from our local suppliers i.e.

Garibsons, Masoom and Qandhari were also analyzed.

101

The entire study was conducted at the Centre of Excellence (COE) laboratory at English

Biscuit Manufacturers Pvt. Ltd. Karachi, Pakistan.

4.1.2.2. Identification of Wheat Source

Wheat flour suppliers (millers) provided all the basic information about wheat source and

flour on a sheet at paper that is called certificate of analysis (COA). Table 7 showed the

collective information of wheat sources for the fiscal year (Jul 2014 to Jun 2015).

- Garibsons maintained their supplies from only one source that is Mirpurkhas.

- In November 2014, Garibsons utilized partially Ukraine wheat which later on was

replaced with local source as per our instruction.

- Nawabshah was the local source for Masoom.

- Matiari flour was utilized in April and May 2015; they used wheat from variety of

source located in Sind.

- Nowrangroy an Indian source, they used their own wheat and didn’t share the

exact location.

102

Table 7: Month wise wheat source utilized by flour suppliers.

Month Masoom Garibsons Qandhari Nowrangroy Matiari

July Nawabshah Mirpurkhas Dadu and Its surrounding - -

August Nawabshah Mirpurkhas Dadu and Its surrounding - -

Sep Nawabshah Mirpurkhas Dadu and Its surrounding - -

Oct Nawabshah Mirpurkhas 50% U, 50% (Dadu,

Larkana and Nawabshah) Indian

-

Nov

80 NS , 20

Ukraine, later

on 100 NS

Mirpurkhas 50% U, 50% (Dadu,


-

Dec Nawabshah Mirpurkhas 50% U, 50% (Dadu,


-

Jan Nawabshah Mirpurkhas 50% U, 50% (Dadu,


-

Feb Nawabshah Mirpurkhas Sanghar Indian -

March Nawabshah Mirpurkhas Sanghar - -

April Nawabshah Mirpurkhas Sanghar

-

Sindh

(Mixed

Location)

May Nawabshah Mirpurkhas Sanghar

-

Sindh

(Mixed

Location)

Jun Nawabshah Mirpurkhas Sanghar - -

4.1.2.3. Testing of Wheat Samples in Centre of Excellence (COE- A lab used for

research in EBM).

Wheat samples provided by suppliers were analyzed on monthly basis through

KERNELYZER as this was one of the facilities for wheat testing at COE. The wheat was

analyzed for determining the following factors,

i. Protein

ii. Moisture

iii. Gluten

iv. Zeleny

103

Furthermore, few physical tests on wheat were also conducted as listed below,

i. Avg. weight of wheat kernel

ii. Avg. diameter of wheat Kernel

iii. Avg. length of wheat kernel

4.1.2.4. Physicochemical analysis of Flour

Sample from each flour supplies received from all sources were drawn and analyzed for

the following parameters,

i. Moisture Content %

ii. Gluten Content %

iii. Gluten Index

iv. Ash %

v. Particle size analysis (on 160µm, 125 µm and Bottom)

vi. Damaged Starch Content

vii. Farinograph analysis


4.1.3.1. Physical Analysis of wheat

- Wheat from Mirpurkhas had the largest length and smallest diameter of the

kernel.

- Nawabshah wheat was second in the smallest diameter after Mirpurkhas.

- Imported wheat from Ukraine had smallest length, and lowest weight.

4.1.3.2. Instrumental Analysis of wheat

- Highest protein content (13.53%) was reported in mixed wheat (Dadu, Larkana

and Nawabshah) provided by Qandhari whereas lowest (11.93%) was reported in

Sanghar wheat.

- Highest moisture content (10.88%) was reported in Nawabshah wheat whereas

lowest (9.81%) reported in Mirpurkhas wheat.

104

- Highest gluten content (22.33%) was reported in mixed wheat (Dadu, Larkana and

Nawabshah) whereas lowest (20.42%) reported in Sanghar wheat.

Table 8: Instrumental analysis of wheat (Source wise).

Supplier Source Protein% Moisture (%)

Gluten Zeleny

Masoom Nawabshah 12.78 10.88 21.67 35.22

Garibsons Mirpurkhas 12.23 9.81 22.07 34.07

Qandhari Sanghar 11.93 10.78 20.42 41.33

Qandhari Dadu, Larkana and Nawabshah

13.53 10.19 22.33 28.42

Imported Ukraine 12.31 10.8 21 37.75

Table 9: Physical analysis of wheat (Source wise).

Supplier Source Weight (gm)

Diameter (mm)

Length (mm)

Masoom Nawabshah 2.88 2.83 5.9

Garibsons Mirpurkhas 2.42 2.68 6.13

Qandhari Sanghar 2.87 3.02 6.08

Qandhari Dadu, Larkana and Nawabshah

2.18 3.12 5.99

Imported Ukraine 2.08 2.88 5.56

105

Figure 93: Instrumental and physical analysis of wheat (Source wise)

4.1.3.3. Physicochemical analysis of flour

a) Moisture Content

Trend of high moisture content was observed in Nawabshah (Masoom), Dadu and its

surroundings (Qandhari) and Indian source. Whereas lowest moisture content was

observed in Matiari flour. Rest of the samples maintained the moisture level from

13.5 to 14%.

b) Ash Content

Ash content was found below specification max. limit (0.5%).

c) Gluten Index

Lowest GI was observed in Matiari which has lowest ash as well, however it had high

DG. Please note that Matiari provided their supplies on April and May, in these

months low GI trend was observed in all supplies.

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

Nawab Shah

Mirpurkhas

Sanghar

Dadu, Larkana andNawabshah

Ukraine

106

d) Gluten Content

Mirpurkhas wheat provided low gluten content flour whereas Matiari was highest

among all. All suppliers except Matiari followed specification defined for soft range

of flour. (7-8.5%).

e) Particle Size

Before mid of November 14, larger particle size flour (3%) were allowed in our specs,

then gradually we shifted towards finest particle size. Indian flour and Matiari flour

provided their flour on finest side.

f) Damaged Starch

Trend of low damaged starch content in observed in Matiari flour, Mirpurkhas,

Nawabshah, whereas all sources provided from Qandhari were reported on higher

side. Whereas Indian source had high level of damaged starch.

4.1.3.4. Farinograph

There is no such clear trend observed in any flour sources from different Farinographic

parameters, remained constant during testing.

Table 10: Moisture, Ash and Gluten analysis

Supplier Source Moisture Ash (%) GI DG

(%)


Masoom 80 NS , 20 Ukraine, later on 100 NS 14.24 0.42 89.94 8.26


Qandhari Dadu and Its surrounding 14.08 0.32 73.86 8.22

Qandhari

50% U, 50% (Dadu, Larkana and

Nawabshah) 13.64 0.41 92.17 8.23


Matiari Interior Sindh 13.31 0.30 62.27 9.08

Nowrangroy Indian 14.16 0.40 85.23 8.37

107

Table 11: Particle size and damaged starch analysis

Supplier Source 160 µm 125 µm Bottom Damaged

starch (UCD)


Masoom 80 NS , 20 Ukraine, later on 100 NS 2.97 26.66 81.23 21.33


Qandhari Dadu and Its surrounding 0.67 20.66 78.66 NA

Qandhari

50% U, 50% (Dadu, Larkana and

Nawabshah) 0.83 20.31 81.16 23.34


Matiari Interior Sindh 0.18 24.43 75.39 19.90

Nowrangroy Indian 0.29 16.48 84.03 24.73

Table 12: Farinographic analysis of flour samples

Supplier Source DDT

(min) DS (min) WA (%) FQN

DoS

(ICC)

Garibsons Mirpurkhas 2.17 5.51 59.01 57.09 85.98

Masoom

80 NS , 20 Ukraine, later on

100 NS 2.19 5.61 58.11 49.57 82.72

Masoom Nawabshah 2.86 5.12 59.24 55.64 88.81

Qandhari Dadu and Its surrounding 3.40 6.36 59.71 76.04 86.23

Qandhari

50% U, 50% (Dadu, Larkana

and Nawabshah) 2.19 6.34 59.14 64.00 75.63

Qandhari Sanghar 2.90 5.27 61.61 59.88 91.94

Matiari Interior Sindh 3.65 4.85 64.22 59.93 90.36

Nowrangroy Indian 2.21 7.70 61.59 69.79 56.03

108

Figure 94: Moisture, Ash and Gluten analysis

Uk/U Ukraine, NS Nawabshah

Figure 95: Particle size analysis (%)


0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

Moisture Ash (%) GI DG (%)

Mirpurkhas

80 NS , 20 Uk

Nawabshah

Dadu and Itssorrounding

50% U, 50% (Dadu,Larkana andNawabshah)Sanghar

Interior Sindh

Indian

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

160 µm 125 µm Bottom

Mirpurkhas

80 NS , 20 Uk

Nawabshah

Dadu and Its sorrounding

50% U, 50% (Dadu, Larkanaand Nawabshah)

Sanghar

Interior Sindh

Indian

109

Figure 96: Farinographic analysis of flour samples


Figure 97: Damaged Starch in various flour samples


0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

DDT(min) DS(min) WA(%) FQN DoS (ICC)

Mirpurkhas

80 NS , 20 Uk

Nawabshah

Dadu and Its sorrounding

50% U, 50% (Dadu, Larkanaand Nawabshah)

Sanghar

Interior Sindh

Indian

21.49 21.33 22.0723.34

25.99

19.90

24.73

0.00

5.00

10.00

15.00

20.00

25.00

30.00

Mirpurkhas 80 NS , 20 Uk Nawabshah Dadu and Itssorrounding

50% U, 50%(Dadu, Larkana

andNawabshah)

Sanghar Interior Sindh Indian

Damaged Starch (UCD)

UCD

110

Figure 98: Trend of damaged Starch supplier wise (Numeric values on X axis shows the

month i.e. 1 Jul)

4.1.3.5. Observation of line behavior of flour on production lines

Following production lines were processing soft product,

i. Line 3

ii. Line 4

iii. Line 5

Table 13: Line observation of flour. (Numbers mentioned in bracket after source name

indicating rating of line behavior for the month)

18

19

20

21

22

23

24

25

26

27

28

4 5 6 7 8 9 10 11 12

Damaged Starch

Garibsons

Masoom

Qandhari

Matiari

Nowrangroy

Month Masoom Garibsons Qandhari Nowrangroy Matiari

July Nawabshah Mirpurkhas Dadu and Its surrounding - -

August Nawabshah Mirpurkhas Dadu and Its surrounding - -

Sep Nawabshah Mirpurkhas Dadu and Its surrounding - -

Oct Nawabshah (3) Mirpurkhas (2)


and Nawabshah) Indian Source (1) Sindh

Line

# 3

Very less utilization Fat => Less fat up to 4

kg, Ammonia => Nil

Not Utilized in Soft dough

product

Fat => Less fat up to 4

kg, Ammonia => Nil,

Utilized with Garibsons

-

111

4

Fat => Standard,

Ammonia => Nil,

Utilized with

Garibsons


kg, Ammonia => Nil


product

Fat => Standard or Less

fat , Ammonia => Nil to

0.1 kg, Utilized with

Garibsons

-

7

Fat => Less fat,

Ammonia => Nil


kg, Ammonia => Nil,

Utilized with

Nowrangroy


product


kg, Ammonia => Nil,


-

Nov

80% Nawabshah ,

20% Ukraine, later

100% Nawabshah (2)

Mirpurkhas

(performed better in

later phase) (3)



Line

#

3

Very less utilization

Fat => Standard to

extra, Ammonia => 0.2-

0.3 kg


product Not utilized

-

4

Fat => Standard or

less fat, Ammonia =>

nil to 0.3 kg

Fat => Standard to

extra, Ammonia => 0.3

kg


product

Fat => Standard or less

fat, Ammonia => nil to

0.1 kg, utilized with

Masoom

-

7

Fat => Standard,

Ammonia => 0.2 kg Fat => Standard to 2kg

extra, Ammonia => 0.2

to 0.3 kg


product


fat, Ammonia => nil,

0.1 and 0.3 kg, utilized

with Masoom and

Garibsons

-

Dec Nawabshah (2) Mirpurkhas (2)



Line

#

3

Fat => less fat,

Ammonia => nil to 0.1

kg

Fat => Standard,


kg


product

Fat => Less fat,

Ammonia => Nil,


and Masoom

-

4

Fat => Standard or

less fat, Ammonia =>

nil


fat, Ammonia => nil


product




-

7

Fat => less fat,

Ammonia => 0.4 kg

Fat => less fat,

Ammonia => 0.4 kg


product

Fat => less fat,

Ammonia => 0.4 kg,

utilized with Masoom

and Garibsons

-

Jan Nawabshah (3) Mirpurkhas (2)



Line

#

3

Fat => Standard fat,

Ammonia => 0.1 kg,

utilized with

Garibsons and

Nowrangroy


Ammonia => 0.1 kg,


and Nowrangroy


product


Ammonia => 0.1 kg,


and Garibsons

-

4


Ammonia => 0.2 kg Fat => Standard or less

fat, Ammonia => nil


product




-

7


Ammonia => 0.1 to


Nowrangroy


Ammonia => 0.1 to 0.3

kg, Utilized with

Nowrangroy


product


Ammonia => Nil to 0.3

kg, Utilized with

Masoom and

Garibsons

-

Feb Nawabshah (2) Mirpurkhas (2) Sanghar Indian Source (1) Sindh

Line

# 3

Fat => less fat,


Fat => less fat,



product Fat => less fat,


-

112

kg, utilized with

Nowrangroy

kg, utilized with

Nowrangroy

kg, utilized with

Masoom and

Garibsons

4


Ammonia => 0.3-0.4

Kg




Nowrangroy


product




Masoom

-

7


Ammonia => 0.4 Kg,

utilized with

Garibsons


Ammonia => 0.4 Kg,



product - -

March Nawabshah (1) Mirpurkhas (2) Sanghar (3) Indian Source Sindh

Line

#

3


Ammonia => 0.1-0.2

Kg, utilized with

Garibsons


Ammonia => 0.1-0.2

Kg, utilized with

Masoom

Fat => Standard fat, Ammonia

=> 0.2 Kg, utilized with

Garibsons

- -

4


Ammonia => 0.1 Kg,

In combination with

Garibsons, Fat =>

Standard fat,

Ammonia => 0.2 Kg,

In combination with

Qandhari

Fat => Standard,

Ammonia => 0.3kg


=> 0.3 Kg, In combination

with Garibsons

- -

7


Ammonia => 0.2-0.4

Kg, utilized with

Garibsons


Ammonia => 0.2-0.3

Kg, utilized with

Masoom

- -

April Nawabshah (2) Mirpurkhas (2) Sanghar Indian Source Sindh (1)

Line

#

3



Kg, In combination

with Garibsons


Ammonia => nil to

0.2kg


product -



Kg, In combination with

Garibsons

4


Ammonia => 0.2 Kg,

In combination with

Garibsons


Ammonia => nil-0.2 Kg


product -


Ammonia => nil

7


Ammonia => 0.5 Kg


product -

In combination with

Garibsons

May Nawabshah (3)

Mirpurkhas (It

improved in later

phase) (2)

Sanghar (4) Indian Source Sindh (1)

Line

#

3


Ammonia => 0.35 Kg



Kg


=> nil to 0.2 Kg, utilized with

Masoom

- -

4


Ammonia => 0.2-0.25

Kg utilized with

Matiari, Fat =>

Standard fat,

Ammonia => 0.35,

utilized with

Garibsons


Ammonia => 0.1 Kg


=> 0.25 Kg, utilized with

Matiari

-


Ammonia => 0.2-0.25 Kg

utilized with Masoom,


Ammonia => 0.25 Kg,

utilized with Qandhari

7 In combination with all, 0.5 kg ammonia - -

113

From October onward we started collecting observation of line behavior of flour derived

from wheat source. Fat and leavening agent quantity determine the impact of flour

quality (level of softness) on production lines. Less fat (than standard) and ammonium bi

carbonate (shortly ammonia) quantity less than 0.4 kg represents softness of the flour.

On standard recipe, soft flour will produce low dense dough and ultimately cookies of

reduced weight (than the standard), for hard flour situation becomes opposite. In both

cases wastages are carried out on production lines. Considering the condition, fat or

ammonia is decreased or increased.

Following observations were recorded,

- Most of the time imported source (Ukraine) Maida was used in production of soft

dough product but didn’t perform as desired because of the composition

variations.

- Imported source wheat flour (Nowrangroy flour) behaved extra ordinary soft

whenever it was utilized in Soft dough product

- Matiari flour also behaved soft.

- Garibsons was very consistent providing flour which behaved soft.

- Masoom was little bit inconsistent providing flour especially In May and Jun 15.

4.1.4. Conclusion

Nowrangroy proved to be providing flour from best quality of wheat source, whereas

Mirpurkhas variety provided by Garibsons behaved consistently as soft, Nawabshah

wheat was inferior as compared to the Mirpurkhas wheat variety. Mixed wheat utilized

by Qandhari (Dadu, Larkana, Nawabshah and Sanghar) didn’t behave up to the mark at

Jun Nawabshah (2) Mirpurkhas (1) Sanghar Indian Source Sindh

Line

#

3 Not Utilized in Line 3


Ammonia => 0.1 Kg


product - -

4


Ammonia => 0.4 Kg


Ammonia => 0.1 Kg


product - -

7


Ammonia => 0.5 Kg,

utilized with

Garibsons


Ammonia => 0.5 Kg,


utilized few quantity in Soft

dough product - -

114

the processing line. Ukraine wheat whenever used in combination with our local supplies

was responsible for the hardness in the flour.

If correlating parameters of wheat samples with line behavior, Garibsons (Mirpurkhas)

behaved as softest among Qandhari and Masoom, utilized wheat with large kernel length

(6.13 mm) and smallest diameter (2.68 mm). No other clear correlation found as per

instrumental and physical analysis of wheat.

Finest particle size also proved to be soft, however low damaged starch content were

preferred. On review of data of the whole year, it was found that the flour which had

damaged starch value below 22 UCD, behaved as soft at production lines, as in the case

of Matiari, Garibsons and Masoom. The flour supplies when exceeded the mentioned

limit of DS, it behaved hard in production lines. The Nowrangroy variety performed

differently (having high damaged starch content with fine particle size behaved soft) as

it might be due to wheat source, it was produced in India where processes and wheat

source/nature was different and unknown to us.

Theoretically, low moisture content and high gluten content lead to hard nature of flour,

but it was not true in the case of Matiari, only difference in damaged starch was

significant among all. Matiari recently installed a milling unit that produced finest particle

flour with low damaged starch content.

On the whole it may be concluded that if wheat taken from different location used as in

the case of Matiari flour and the wheat from Mirpurkhas proved as soft wheat following

Nawabshah wheat. However it was not only wheat variety which affected the quality of

flour, it also the amount of damaged starch, particle size and ash etc. that determined

the quality of flour. The milling process if controlled also contributes to the soft or hard

nature of flour.

115

4.2. Dough stickiness and mitigation in product.


Dough stickiness is a routine problem faced during production of biscuits, specially

observed in sheeted products. If dough stickiness is resolved immediately or before it

goes to baking unit, wastages may be controlled and company can be benefitted,

4.2.2. Problems Due to Stickiness

Following are the problems due to stickiness,

Scratch bottom

Inappropriate Sheet formation of biscuit

Dimensional variation

4.2.3. Possible factor affecting stickiness of the dough

Dough stickiness is a common problem which may be due to either quality of raw material

or processing methods and parameters. Possible root causes and their mechanisms are

discussed below,

a) Flour Moisture Content

Moisture Content in Flour is directly related to water absorption capacity of flour. Flour

having high moisture content has tendency to have low moisture absorption, if recipe

water is not adjusted according to moisture of flour, extra water will cause stickiness on

dough.

b) Damaged starch and α-amylase activity

Damaged starch is one of the prominent factor for causing stickiness in dough. During

harsh milling of wheat, damaged starch is produced, which increases the availability of

substrate for α-amylase to hydrolyze starch into dextrins and many other degraded

products. Dextrins and sugars have tendency to absorb more water and to cause

stickiness. The high amylase activity will also increase the problem because small

116

molecules will increase in number and therefore will increase the interaction of water

with degraded molecules.

c) Inappropriate Recipe Water/Human Error

It is a normal practice to follow the same mixing parameters and recipe settings for next

flour supplies and not significant variation is performed. If added water in recipe is not

adjusted according to flour analysis report it can cause stickiness or many other

problems.

d) Unbalanced Recipe Design

Performance of any product on Production line is totally dependent on Recipe design and

it needs to be well adjusted. If it is unbalanced i.e. unbalanced fat and water ratio can

produce stickiness on dough.

e) Particle Size of Flour

Flour having small particle size has high surface area, means water has many sites to be

absorbed. Large particle of flour hydrates less. If water is not adjusted keeping particle

size in view, for example large particle absorbs less water than small particle; extra water

in recipe can cause stickiness on dough.

f) Mixing Parameters (Time, RPM etc.)

Mixing time should be adjusted according to flour properties (DDT, DST). Less mixing time

will reduce water absorption and high mixing time can lead to breaking of protein

network. In both cases stickiness can arise on dough.

g) Environmental Factors/Raw material Temperature and physical condition

Temperature of Raw material and environment affect dough rheology and shape

formation in Cutting unit. Very low raw material temperature like Fat, can have some

adverse effect on rheology of dough, as it sticks on feeding roll of Cutting Unit, pushing

strength of rollers reaches on its highest point, so wet weight can’t be increased more.

117

Very low temperatures of environment and ingredients cause improper mixing.

Absorption, solubility of any material is directly related to temperature. Unbounded and

unabsorbed water produces stickiness on dough.

Figure 99: Flow Chart of work plan to rectify the issue

Monitor Temperature Profile (ingredients

and Environment)

Draw Flour Samples and do complete

Testing

After Gathering Significant Data, Make

relation

Conclude Result

Observe Line Performance of Problematic

and non-problematic Products and collect all

possible data

118

Figure 100. Root Cause Analysis/4M’s techniques to identify the root cause

4.2.4. Approach and mechanism to minimize stickiness from sheeted product

After the complete analysis of root causes three main steps were applied in order to

minimize stickiness as follows,

a) Inclusion of left over dough

Left over dough (10%) was added in fresh dough as it was chemically changed dough; all

reaction had already been taken place. It was the enzymatically inactivated dough, no

conversion of starch into dextrin and water was occurred. Less chances of production of

free water was possible in dough. Left over dough was dry on the surface, it absorbed

free water from the recipe and made fresh dough non sticky.

MATERIAL

STICKINESS

METHOD

Ingredients Sequencing

Chilled Water

Mixing Time

MACHINE

Work Force Allocation

MAN

Mixer over heating

Weighing balance

calibration

Oven Profile

(Zones)

Flour

Left over Dough

Temp.

Monitoring

Wate

r

Machine

Room Dough

Water quantity

Cutting Profile

(Sheet rollers)

Additives

Improper ingredients

weighing

119

b) Chilled Water

Chilled water was added to make dough temperature as per required 36 0C. Enzymes

(proteases and amylases) were activated over certain range which was responsible for

production of free water, liquefaction of starch and protein which made dough sticky.

Mixer gets hot with the passage of time, as mixing proceeds temperature increases,

chilled water prevented mixer to produce heat.

c) Some quantity of Fat added in later Phase

Some fat added (15%) in later phases of mixing to grease the dough and improve machine

ability. It decreased dryness of the dough.

4.2.5. Flour analysis parameters for sheeted products

Table 14 shows that Moisture from 14.1 to 14.5 was found to be suitable for sheeted

product whereas slightly higher gluten content was appropriate to control stickiness

problem (9.34 to 9.59%) as compared to other product i.e. cookies (7-8.5%). As per table

2, low moisture absorption flour was suitable for sheeted product.

Table 14: Flour parameters suitable for sheeted product

Moisture and Glutomatic

System

Parameters Min Max

Moisture 14.1 14.5

DG 9.34 9.59

GI 68.84 74.7

WG 28.56 28.61

PG 19.7 21.3

120

Table 15: Temperature ranges suitable for sheeted product

Temperature Range

Temperature Min Max

Dough 35.5 36.5

Chilled Water 18.5 20.5

Tap Water 27 28.5

Table 16: Farinograph parameter suitable for sheeted product

Farinograph

Parameters Min Max

WA 58.2 59.4

DDT 4.2 5.3

ST 6.5 8.1

DoS (10 min) 39 43

DoS (12 min) 43 64

FQN 85 86

121

Figure 101: Crumb generation

4.2.6. Conclusion:

Before project started, crumb generation was higher than 5.1 %, after applying remedies,

crumb generation has gradually decreased up to 3.49%.

4.97%

7.11%

2.98%

3.98%

6.50%

2.68%

5.07%

3.41%3.74%

4.46%

2.52%2.17%

3.93%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

Crumb Generation in Whole Wheat Slices

Standard % Actual %

122

5. CHAPTER: FLOUR, QUALITY ASSESSMENT AND ITS TREATMENT

5.1. Wheat flour characteristics of different countries


An extensive study on comparative basis was carried out using flour extracted from wheat

of four different locations of three countries (Pakistan, Ukraine and India) with different

ratios.

These wheat were being used in the mills located at Karachi for the production of wheat

flour to be used commercially in baking industry. The baking performance of different

flours differs according to the physicochemical characteristics which consequently govern

the dough rheology and edible properties of the products. It is therefore important that

the physicochemical properties of the flour must be appropriately selected for studies to

govern the entire processing. Varieties of physicochemical parameters were studied that

indicated distinct relationship with dough rheological properties.




5.1.2.1. Material

Commercially available soft wheat flour was received from Masoom Flour Mills Private

Ltd. Karachi, Garibsons Flour Mills Private Ltd. Karachi, Qandhari Roller Flour Mills Private

Ltd. Karachi and Nowrangroy, Agro Pvt. Ltd. India. Masoom utilized local source of wheat

which was obtained from the Sind i.e. Nawabshah. Garibsons utilized Mirpurkhas wheat,

whereas Qandhari provided flour with mixed wheat i.e. 50% Ukraine and 50%

Mirpurkhas. Total 165 samples of flour were evaluated in the study in which 44 samples

from Nawabshah, 49 samples from Mirpurkhas, 58 obtained by mixing 50% Mirpurkhas-

50% Ukraine and 14 samples from India were included.



The moisture content in flour from all sources varied from 13.9 to 14.4%. The flour

123

produced from Nawabshah wheat had highest moisture content whereas flour blended

from wheat of Nawabshah and Ukraine at the ratio of 50%:50% showed the minimum

moisture level (13.92%). Ash level in all flour samples were found in the range of 0.42 to

0.445% which complied the Pakistan standard for wheat flour to be used in biscuit

manufacturing. Protein content varied between 10.21-10.78% which may be categorized

as soft.


The dough development time of flour samples did not show the significant difference.

The higher value of DST was reported in Indian flour as 7.26 min which confirmed the

strong networking of gluten and also held maximum WA. Lowest WA was reported in

Nawabshah wheat flour which also showed reduced DST. It was indicated that DST was

positively correlated to WA, i.e. the high WA will have the high dough stability. The direct

relationship between WA and DST has been reported recently by Diosi and coworkers

(2015).

5.1.3.3. Damaged Starch and Particle size distribution

The Indian wheat flour showed the highest level of damaged starch (25 UCD) whereas

low damaged starch was reported in Nawabshah supplies. The 100% Indian wheat flour

contained more of fine particles whereas Nawabshah wheat had the least amount of

small particle of flour (table 20). The relationship between damaged starch and particle

size is a well-established factor and is confirmed by various other workers (Barak et al,

2014; Kang et al; 2014 and Ali et al, 2014)

Table 17. Physiochemical Properties of different wheat sources

Source and Ratio of Wheat Moisture (%) Ash (%) Protein (%)

100% Local- Nawabshah 14.40 ± 0.31 0.44 ± 0.03 10.61 ± 2.30

100% Local- Mirpurkhas 14.27 ± 0.36 0.44 ± 0.06 10.21 ± 0.17

50% Mirpurkhas- 50% Ukraine 13.92 ± 0.61 0.42 ± 0.07 10.31 ± 0.23

100% Indian 14.04 ± 0.49 0.43 ± 0.03 10.78 ± 0.34

Standard deviation is indicated as ± after the mean value

Table 18: Farinograph Parameters of flour from different wheat sources

Source and

Ratio of Wheat DDT(min) DST(min) WA (%) FQN DoS (ICC)

100% Local-

Nawabshah 2.07 ± 0.89

4.93 ±

2.16

56.48 ±

1.54

44.6 ±

17.78

83.77 ±

14.34

100% Local-

Mirpurkhas 1.83 ± 0.32

5.06 ±

2.50

57.99 ±

1.68

51.38 ±

22.90

84.92 ±

13.10

50%

Mirpurkhas-

50% Ukraine

2.19 ± 1.00 5.79 ±

2.31

58.97 ±

1.23

60.40 ±

25.32

79.40 ±

16.86

100% Indian 1.96 ± 0.33 7.26 ±

2.63

62.04 ±

1.03

60.43 ±

39.20

56.21 ±

15.46


125

Table 19: Glutomatic properties of flour from different wheat sources

Source and Ratio of

Wheat

Wet

Gluten

(%)

Passed

Gluten

(%)

Retained

Gluten

(%)

Gluten

Index

Dry Gluten

(%)

Water

Retained

(%)

100% Local-

Nawabshah

23.48 ±

1.73

1.89 ±

0.70

21.59 ±

1.62

92.02 ±

2.91 8.13 ± 0.32

15.35 ±

1.60

100% Local-

Mirpurkhas

23.39 ±

0.81

1.97 ±

0.80

21.42 ±

0.61

91.41 ±

3.41 8.03 ± 0.28

15.37 ±

0.65

50% Mirpurkhas-

50% Ukraine

23.77 ±

1.61

1.70 ±

0.72

22.07 ±

1.54

92.79 ±

2.80 8.27 ± 0.27

15.49 ±

1.56

100% Indian 24.38 ±

1.04

2.71 ±

1.13

21.67 ±

0.89

88.86 ±

4.05 8.37 ± 0.18

16.00 ±

0.91


126

Table 20. Damaged Starch and Particle Size analysis of flour

Source and

Ratio of

Wheat

Damaged Starch Content Particle Size(% Retention)

UCD AACC % Farrand 160 µm 125 µm Bottom

100% Local-

Nawabshah

20.39

± 1.47

5.81 ±

0.39

23.01 ±

2.92

1.50 ±

0.71

23.61 ±

2.54 74.89 ± 2.64

100% Local-

Mirpurkhas

22.5 ±

1.07

6.51 ±

0.49

28.78 ±

3.53

1.00 ±

0.54

19.08 ±

2.53 79.92 ± 2.58

50%

Mirpurkhas-

50%

Ukraine

23.96

± 1.23

7.00 ±

0.48

33.62 ±

3.68

0.89 ±

0.56

17.58 ±

3.96 81.52 ± 4.26

100% Indian 25.0 ±

1.25

7.38 ±

0.49

36.76 ±

4.38

0.38 ±

0.24

16.07 ±

2.09 83.55 ± 2.05


Figure 102: Effect of Particle size on Damaged Starch content

100% Local-Nawabshah

100% Local-Mirpurkhas

50% Mirpurkhas -50% Ukraine

100% Indian

R² = 0.8678

55

56

57

58

59

60

61

62

63

15 20 25 30

Wat

er

Ab

sorp

tio

n (

%)


127

Figure 103: Effect of Particle size on Damaged Starch content of Flour

5.1.3.4. Glutomatic proteins of flour from different wheat sources

The Indian wheat flour produced high WG, PG and DG, lowest GI and high water

absorption by proteins in comparison to others, it also showed highest WA from

Farinograph, highest protein contents (table 19) and highest UCD (table 20). It showed

that water held in dough was due to damage starch and gluten as the percentage was

higher. Secondly the results indicated that GI and water had good coordination as both

decreased inspite of the fact that all the Glutomatic proteins increased while dry

Gluten for all flour samples were same.

5.1.3.5. Damaged Starch affecting Water absorption of Flour

It is now a well-established fact that damaged starch is significantly correlated with

water absorption as also confirmed from our result (R2=0.868). High contents of

damaged starch lead to more water absorption as shown in fig. 102. The direct

relationship of damage starch and water absorption has been reported by various

authors from time to time.

5.1.3.6. Particle size affecting Damaged Starch Content

The quantity of damaged starch was highly correlated with the distribution of the

particle size of flour (R2=0.98) as shown in fig. 103 that confirmed the increase in

damaged starch level on fine grinding with same protein level.

100% Local-Nawabshah

100% Local-Mirpurkhas

50% Mirpurkhas -50% Ukraine

100% Indian

R² = 0.9788

74

75

76

77

78

79

80

81

82

83

84

85

15 20 25 30

Par

ticl

e b

elo

w 1

25

mic

ron

(%

)


128

5.1.4. Conclusion

The quality of flour depends on variety of factors such as it is related to the wheat

sources that governs flour’s composition and also depends on the type of milling and

blending the streams. DS level, wet gluten and particle size were contributed on the

flour water absorption capacity. Indian wheat flour composed of high protein and

lowest ash content and also produced high dough stability, high water absorption and

less degree of softening.

The decreased of damaged starch level was found in the flour obtained from

Nawabshah wheat, whereas Indian wheat produced high level of damaged starch. Wet

and dry gluten were highest in Indian wheat flour whereas Pakistani flours had less

wet and dry glutens. Particle size distribution (0 to 125 micron) was found to be

significantly correlated with damaged starch (R2= 0.98) which consequently was

strongly predictive of high water absorption as indicated from Farinograph (R2=0.87).

Rheological behavior showed high water absorption also would have high dough

stability and less degree of softening as found in Indian wheat flour. Pakistani wheat

(Nawabshah and Mirpurkhas) produced dough of biscuit quality (soft) as degree of

softening was higher as compared to others.

The variety of wheat analyzed in different countries as in Hungary (Diosi et al, 2015),

Korea (Kang et al, 2014), China (Zhang et al, 2007), India (Ram et al, 2004), Egypt (El-

Porai et al, 2013) etc. have all shown relationship of a certain parameter to the baking

performance of flour. Further research is required to establish a useful strategy based

on simple physicochemical analysis of flour for exchange of wheat/flour

internationally.

129

5.2. Prediction of damaged starch by assessing some physicochemical

quality of wheat flour.


The baking ability of flour depends on the amount of damaged starch present in flour.

DS may not necessarily be directly determined as DS but it might be determined

indirectly. DS is also much related to other parameters of four determined by other

techniques. For example AWRC values resenting the amount of protein, insoluble

pentosan and minerals are directly linked to DS, if AWRC values increases the DS will

automatically increase and will result in reduced diameter of the biscuits.

In flour mill of Sindh, analysis lab are not well established to perform damaged starch

test. SDmatic system is used worldwide to analyze the damaged starch and is a very

expensive instrument. The objective of the study is to find out other simple methods

which can predict the level of damaged starch and those simple methods may be

established in all type of labs (advance or basic facility of testing). Some correlation of

DS was also tried to find out with sophisticated equipment, i.e. Farinograph and

MVAG.




5.2.2.1. Material

Eighteen flour samples of soft wheat (produced for commercial use in biscuit industry)

from four different mills i.e. Masoom Flour Mills Private Ltd., Ghouri Roller Flour Mills

Private Ltd, Qandhari Roller Flour Mills Private Ltd. and Madina Flour Mills Private Ltd.

were included in the study. Numbers after the mill name (first name) represented the

sample number for specific mill.

Analytical grades reagents/chemicals were used procured from the distributor of

MERCK (Darmstadt, Germany) in Pakistan, Labline Pvt. Ltd.

130


5.2.3.1. Damaged starch versus physicochemical properties of flour

It is well acknowledged among the researchers that damaged starch enhance

absorption of water to the extreme as compared to native starch. The

physicochemical factors of wheat flour is also stated to be affected by water added

during conditioning of wheat which ultimately converts into moisture in flour

(Nooroka et al 2009) but currently it showed the in significant relation between water

and damaged starch (Table 21). It is possible that flour samples included in the study

were milled freshly. Furthermore, the starch granule damaged during the milling of

wheat did not have good opportunity to absorb moisture from environment or low

humid weather condition in Sindh which might cause the in appropriate water

retention in all flour samples. Difference in level of moisture already present in the

wheat kernels might affected damaged starch as it majorly depends on the condition

of milling and other factors of wheat i.e. mineral and gluten proteins. The direct linear

relationship was observed in ash and protein with the damaged starch content of flour

as indicated earlier (Barrera et al, 2007; Keskin et al, 2012 and Colombo et al, 2008).

The firmness and rigidity of wheat grain closely related with ash and protein contents.

Hard kernel produces more damaged starch in comparison with the soft varieties.

Zeleny values found lowered than such values mentioned before (Fargested et al,

1999) which varied between 30-36. Zeleny values represents the sedimentation

capacity of LMW weight proteins and same value is also indicated by LA-SRC. The

hardness of wheat kernel and its size reduction extent are resemble closely to

damaged starch present in flour. Finer flour requires heavy pressure from rollers and

also need prolong milling time producing more damaged starch. The table 21 showed

that the flour samples Madina-1 and Madina-2 comprising 5.1%, 6.8% of its particles

above 160 µm generated less of damaged starch (5.27%, 5.86%) than the other flour

samples from Masoom flour mill and Ghouri flour mill which had 0.5% and 1.5%

particle size distribution above >160 µm resulting 8.12%, 8.58% damaged starch

respectively. It was shown that the particle size of flour was correlated with other

physicochemical characteristics, for example SRC, AWRC, FN (falling number), gluten

proteins and damaged starch (Barak et al, 2012). Fig. 104 showed R2 value of protein

and damaged starch that was 0.451 in flour confirming mild correlation between

131

these parameters. It may be assumed that approximate values of damaged starch are

usually calculated considering other values and routine analysis of damaged starch is

omitted.

Figure 104: Damaged starch vs total protein contents

Table 21: Physicochemical analysis of different flour samples.

Flour Damaged starch,

%

Moisture, %

Ash, %

Protein, %

Zeleny

Particle size

Above 160

µm, %

160-125

µm, %

Below 125

µm, %

Madina 1

5.27 14.9 0.527 10.4 32 5.1 16.6 78.3

Madina 2

5.86 15 0.462 9.7 30 6.8 18.2 75

Qandhari 2

6.11 13.1 0.526 10.8 31 0.7 10.3 89.2

Qandhari 5

6.18 12.8 0.433 10.5 36 1.1 9.2 89.7

Ghouri 2 6.31 13.7 0.466 10.8 35 2.3 18.7 78

Qandhari 1

6.35 13.1 0.508 11.3 33 1.3 10.2 88.5

Ghouri 1 6.41 13.3 0.526 10.6 35 2.8 19.1 78.1

Masoom 2

6.5 14.1 0.568 11.8 34 0.5 11 88.5

Qandhari 4

6.64 13.1 0.527 11.1 33 1.8 12 86.2

Masoom 4

6.76 13.8 0.539 11.8 35 0.7 12.7 86.6

Ghouri 4 6.86 13.3 0.472 10.4 32 4.5 20.5 75

Ghouri 3 6.9 13.6 0.45 11.1 34 5.1 20.4 74.5

Masoom 3

6.96 14.2 0.526 11.5 36 0.9 13.2 85.9

R² = 0.451

9

9.5

10

10.5

11

11.5

12

12.5

0 2 4 6 8 10 12

Pro

tein

(%

)

Damaged Starch (%)

132

Qandhari 3

7.03 12.6 0.503 11.2 33 2.1 9.7 88.2

Masoom 1

7.06 13.6 0.573 11.9 34 0.9 10.2 88.9

Masoom 6

7.84 13.5 0.677 11.6 32 0.8 11.5 87.7

Masoom 5

8.12 13.8 0.651 11.5 32 0.5 10 89.5

Ghouri 5 8.58 13 0.444 11.9 33 1.5 17 81.5

5.2.3.2. Relationship of DS with SRC and AWRC values

The value of SRC (solvent retention capacity) showed some relationship with the other

quality parameters of flour that is quite important to predict performance of flour

during baking. SRC tests were compared with damaged starch values as shown in the

table 22 where the each type of SRC representing specific component present in the

flour. A positive relationship between AWRC and DS were achieved as AWRC

increased (62.86% to 77.99%), the damaged starch also increased (5.27% to 8.53%) as

shown in fig. 2. AWRC values are constructed on three components’s solubility in

flour i.e. Damaged Starch, proteins and water insoluble pentosans. SC-SRC (Sodium

carbonate SRC), AWRC and W-SRC (water SRC) were positively linked with each other

and found inversely related to the diameter of cookies (Guttieri et al, 2006) indicating

that damaged starch is a good predictor to identify dimensional property of end

product.

Lactic acid SRC (LA-SRC) values were positively correlated to damaged starch (fig. 105).

LASRC is more closely associated with amount of HMW- gluten proteins which further

are directly correlated to bread quality i.e. its loaf volume. The damaged starch is

inversely linked to the dimensional properties of the biscuit. Earlier it is reported that

the higher portion of glutinins in flour leads to reduced diameter of biscuit due to the

extra cohesiveness of the dough (Wieser and Kieffer 2001; Wieser et al, 2003). In Su-

SRC, flour constitutes i.e. bran and LMW-gluten that is retained in syrup. The values

of Su-SRC were found to have positive relation with DS.

The glutenins are high molecular weight proteins because of many sulfer-sulfer

bridges present in the molecule. On the other hand gliadin has only one sulfer-sulfer

133

bridge. The property was correlated to DS (fig. 102-105). The amount of gliadin and

glutenin proteins as measured by chemical tests as SC-SRC, AWRC, LA-SRC, W-SRC and

Su-SRC and represents the viscoelasticity of dough which was also related to DS and

to the end quality.

Figure 105: DS vs AWRC

Figure 106: DS vs SC-SRC

Figure 107: DS vs W-SRC

R² = 0.697

55%

60%

65%

70%

75%

80%

0 2 4 6 8 10 12

AW

RC

(%

)

Damaged Starch (%)

R² = 0.690

65%

75%

85%

95%

105%

115%

0 2 4 6 8 10 12

SC-S

RC

(%

)

Damaged Starch (%)

R² = 0.359

55%

60%

65%

70%

75%

80%

85%

0 2 4 6 8 10 12

WSR

C (

%)

Damaged Starch (%)

134

Fig. 108: DS vs LA-SRC

Figure 109: DS vs Su-SRC

Table 22: SRC and AWRC of wheat flour samples.

Flour DS, % AWRC,

% WSRC,

% SCSRC,

% SuSRC,

% LASRC,

%

Madina 1 5.27 62.86 61.24 77.51 86.81 74.98

Madina 2 5.86 65.56 63.44 75.98 85.29 74.87

Qandhari 2 6.11 64.72 67.89 74.82 92.63 73.83

Qandhari 5 6.18 69.92 68.35 84.03 98.13 78.31

Ghouri 2 6.31 71.75 71.25 88.49 99.85 81.52

Qandhari 1 6.35 70.66 71.85 89.07 105 80.16

Ghouri 1 6.41 70.13 69.83 85.31 101.08 81.83

Masoom 2 6.5 72.48 70.78 89.8 101.22 81.29

Qandhari 4 6.64 71.55 67 90.95 96.19 76.7

Masoom 4 6.76 72.23 72.13 89.89 102.36 82.91

Ghouri 4 6.86 74.99 65.67 87.29 100.18 78.16

Ghouri 3 6.9 72.56 80.03 89.09 93.66 77.04

Masoom 3 6.96 72.37 74.97 93.32 100.33 80.39

Qandhari 3 7.03 71.73 74.39 90.43 104.89 79.31

Masoom 1 7.06 70.97 70.87 90.98 101.83 82.12

Masoom 6 7.84 74.47 73.17 91.27 98.13 91.17

R² = 0.486

65%

70%

75%

80%

85%

90%

95%

0 2 4 6 8 10 12

LASR

C (

%)

Damaged Starch (%)

R² = 0.101

75%

80%

85%

90%

95%

100%

105%

110%

0 2 4 6 8 10 12

Su-S

RC

(%

)

Damaged Starch (%)

135

Masoom 5 8.12 72.97 73.33 91.49 93.98 80.81

Ghouri 5 8.58 77.99 72.56 106.07 97.96 86

5.2.3.3. Farinographic parameters versus damaged starch

The table 23 represented Farinograph parameters such as time for dough formation

(DDT), water absorption (WA), two type of degree of softening (DoS), dough stability

time (DST) and Farinograph quality number (FQN). The compositional values of the

flour were found to be highly predictive for dough behavior during processing. The

parameters associated with dough firmness and rheology were true indicators of the

final texture of biscuits. The damaged starch granules can absorb large amount of

moisture as compared to native molecules. The fig. 111 showed that damaged starch

responsible for more water absorption increased the mixing time or the dough

development time (DDT). Actually, some chemical changes such as molecular

degradation from starch to dextrins, then to maltose and finally to glucose (through

amylases) cause for dough rigidity. The overall impact may be observed on biscuit that

becomes small in size (diameter reduced) (Barak et al, 2012). Another visible change

due to large amount of water absorption may be seen on the surface of the biscuit or

the top grain. Extra water takes more time to be evaporated during baking, because

water is taken up by sugar in the recipe to form syrup that changes dough viscosity

and delay in water evaporation effects pattern of surface crack on the surface of the

biscuit (Barrera et al 2007). Excess of water taken up by DS in dough disturbs the

gluten network of dough i.e. the dough rheology is adversely affected (Haynes et al,

2009; Singh and Khatkar, 2005)

Figure 110: DS vs WA.

R² = 0.810

54

56

58

60

62

64

66

0 2 4 6 8 10 12

Wat

er

Ab

sorp

tio

n (

%)

Damaged Starch (%)

136

Figure 111: DS Vs dough quality parameters DDT.

Table 23: Farinograph parameters in various flour

Flour DS, % DST, min

WA, % FQN DDT, min

DoS ICC, FU

DoS, FU

Madina 1 5.27 3.6 55.7 33 1.9 83 57

Madina 2 5.86 7.1 55.9 81 2.4 88 50

Qandhari 2 6.11 6.5 60 79 1.9 65 43

Qandhari 5 6.18 7.9 59.2 66 2.9 60 37

Ghouri 2 6.31 7.7 58.6 91 2 52 36

Qandhari 1 6.35 10.3 60.6 120 2.9 49 18

Ghouri 1 6.41 5.9 58.7 78 2.2 53 38

Masoom 2 6.5 5.7 61.1 75 4.7 86 51

Qandhari 4 6.64 9.9 59.1 42 2.3 51 32

Masoom 4 6.76 6.1 60.9 88 4.2 60 34

Ghouri 4 6.86 6.8 59.7 88 5.7 78 40

Ghouri 3 6.9 4.5 62.3 59 3.8 108 78

Masoom 3 6.96 4.5 61 75 3.3 61 48

Qandhari 3 7.03 9.1 61.4 106 2 55 26

Masoom 1 7.06 5.3 62.7 65 2.4 99 68

Masoom 6 7.84 7.3 62.5 87 5.2 78 41

Masoom 5 8.12 7.8 64.4 92 6 86 40

Ghouri 5 8.58 4.5 64.6 65 3.5 114 71

R² = 0.337

0

1

2

3

4

5

6

7

0 2 4 6 8 10 12

DD

T (m

in)

Damaged Starch (%)

137

Figure 112: DS Vs Beginning of Gelatinization temperature

Figure 113: DS Vs Trough Viscosity

R² = 0.449

59.5

60

60.5

61

61.5

62

0 2 4 6 8 10 12

Be

gin

nin

g o

f ge

lati

niz

atio

n (°C

)

Damaged Starch (%)

R² = 0.456

300

400

500

600

700

800

0 2 4 6 8 10 12

Tro

ugh

Vis

cosi

ty (

BU

)

Damaged Starch (%)

138

Figure 114: DS Vs Final Viscosity

Figure 115: DS Vs Peak Viscosity

R² = 0.420

600

800

1000

1200

1400

0 2 4 6 8 10 12

Fin

al V

isco

sity

(B

U)

Damaged Starch (%)

R² = 0.435

400

600

800

1000

1200

0 2 4 6 8 10 12

Pe

ak V

isco

sity

(B

U)

Damaged Starch (%)

Table 24. Micro Visco-Amylo-Graph parameters of various flour

Flour Damaged starch, %

Beginning of gelatinization PV, BU BV, BU

TV, BU

SV, BU

FV, BU

Torque, BU

Temp. ,°C

Madina 1 5.27 20 61.7 952 360 592 608 1200

Madina 2 5.86 21 61.3 1004 379 625 594 1219

Qandhari 2

6.11 15 61.6 993 297 696 430 1126

Qandhari 5

6.18 19 61.4 1017 348 669 606 1275

Ghouri 2 6.31 11 60.3 1019 358 661 454 1115

Qandhari 1

6.35 20 61.8 946 309 637 331 968

Ghouri 1 6.41 22 61.1 999 363 636 534 1170

Masoom 2

6.5 20 60.1 1041 372 669 461 1130

Qandhari 4

6.64 16 60.6 985 350 635 605 1240

Masoom 4

6.76 17 60.4 957 339 618 500 1118

Ghouri 4 6.86 20 61.1 993 360 633 581 1214

Ghouri 3 6.9 18 60.8 975 384 591 554 1145

Masoom 3

6.96 16 59.9 988 332 656 354 1010

Qandhari 3

7.03 16 60.9 1006 338 668 369 1037

Masoom 1

7.06 17 60.3 984 323 661 301 962

Masoom 6

7.84 18 60.3 938 394 544 528 1072

Masoom 5

8.12 18 60.5 907 350 557 539 1096

Ghouri 5 8.58 15 59.9 603 264 339 408 747

140

5.2.3.4. Damaged starch versus pasting curve of MVAG

The pasting behavior of the dough significantly changed due to the presence of DS in flour

as shown by various viscosities which was caused by the rising heat at different stages

i.e. heating, holding & cooling as mentioned in table 24. As damaged starch increases,

the pasting temperature (PT) was slightly decreased that relates to increase in viscosity

for the first time. The pasting curve shows the close relationship of DS with the

gelatinization of starch, that determines the texture of baking products (Ragaee et al,

2001). The trough viscosity TV is low in presence of damaged starch that will affect the

end quality (Ragaee and Abdel-Aal, 2006). The breakdown (BV) viscosities and setback

(SV) viscosities got decreased in presence of DS because of excess water absorption. The

SV, FV were higher than BV. However, with the increase of damaged starch both of them

decreased. Further, starch retrogradation that showed rearrangement of starch

molecules decreased when DS increased, which also slowed down the process of

syneresis. The pasting curve as obtained from MVAG is a useful indicator of behavior of

DS in dough during baking because its shows how DS affects the dough viscosities at high

and low temperature. The pasting curve will be predictive of final texture of the biscuit.

5.2.3.5. Relationship of Proteins from Glutomatic -2000 and DS

The gluten proteins in industrial process and research are closely related for assessing

flour quality. Glutomatic machine is used to measure parameters i.e. dry gluten (DG),

wet/hydrated gluten (WG), passed gluten (PG), retained gluten (RG), gluten index (GI)

that gives the strength of gluten network and water binding capacity (WBC). The present

studies showed the impact of DS on the Glutomatic proteins (table 25). Positive

association between DS and PG was shown in fig. 116 while inverse relationship with RG

and GI were shown in fig. 117 and 118.

The textural and dimensional characteristics of biscuits is associated with the

composition of flour that determines the WA by the flour. The water of all the hydrophilic

polymers present in flour was high as shown by Farinograph than the WA form

Glutomatic 2000 (WA only by gluten). Actually WA also depends on molecular

Figure 2A:

141

structure/particle size (Stasio et al, 2007) that was also illustrated by the present study

(table 25).

Figure 116: Damaged vs passed gluten

Figure 117: Damaged starch vs retained gluten

Figure 118: Damaged starch vs gluten index

R² = 0.358

0

5

10

15

20

0 2 4 6 8 10 12

Pas

sed

Glu

ten

(%

)

Damaged Starch (%)

R² = 0.383

5

10

15

20

25

30

0 2 4 6 8 10 12

Re

tain

ed

Glu

ten

(%

)

Damaged Starch (%)

R² = 0.403

20

40

60

80

100

0 2 4 6 8 10 12

Glu

ten

Ind

ex

Damaged Starch (%)

A

142

Table 25: Glutomatic Proteins and DS of various flour

Flour Damaged

starch (DS)

Retained gluten (RG)

Passed gluten (PG)

Dry gluten (DG)

Wet gluten (WG)

Water binding capacity (WBC)

Gluten index (GI)

Madina 1 5.27 22.1 2.8 8.2 24.9 16.7 89

Madina 2 5.86 19.8 2.3 7 22.1 15.1 90

Qandhari 2 6.11 19.3 11 9.2 30.3 21.1 64

Qandhari 5 6.18 26.8 2.3 9.6 29.1 19.5 92

Ghouri 2 6.31 16.2 12 9.9 28.2 18.3 57

Qandhari 1 6.35 23.2 3.3 8.8 26.5 17.7 88

Ghouri 1 6.41 20.6 6.8 8.7 27.4 18.7 75

Masoom 2 6.5 16.2 14.8 9.3 31 21.7 52

Qandhari 4 6.64 23.8 2 8.4 25.8 17.4 92

Masoom 4 6.76 17.1 11.9 9.3 29 19.7 59

Ghouri 4 6.86 19.9 8.1 8.9 28 19.1 71

Ghouri 3 6.9 19 10.9 9.5 29.9 20.4 64

Masoom 3 6.96 14.3 16.4 10 30.7 20.7 47

Qandhari 3 7.03 20.2 6.8 8.7 27 18.3 75

Masoom 1 7.06 15.7 15.5 9.9 31.2 21.3 50

Masoom 6 7.84 17 11.5 10 28.5 18.5 60

Masoom 5 8.12 15 13.7 9.4 28.7 19.3 52

Ghouri 5 8.58 13.3 14.6 8.8 27.9 19.1 48

Figure 119: DS vs NG-WA

R² = 0.729

36

38

40

42

44

46

0 2 4 6 8 10 12

NG

-WA

(%

)

Damaged Starch (%)

143

Table 26: DS vs NG-WA

Flour DS, (%) G-WA, (%) F-WA, (%) NG-WA, (%)

Madina 1 5.27 16.7 55.7 39

Madina 2 5.86 15.1 55.9 40.8

Qandhari 2 6.11 21.1 60 38.9

Qandhari 5 6.18 19.5 59.2 39.7

Ghouri 2 6.31 18.3 58.6 40.3

Qandhari 1 6.35 17.7 60.6 42.9

Ghouri 1 6.41 18.7 58.7 40

Masoom 2 6.5 21.7 61.1 39.4

Qandhari 4 6.64 17.4 59.1 41.7

Masoom 4 6.76 19.7 60.9 41.2

Ghouri 4 6.86 19.1 59.7 40.6

Ghouri 3 6.9 20.4 62.3 41.9

Masoom 3 6.96 20.7 61 40.3

Qandhari 3 7.03 18.3 61.4 43.1

Masoom 1 7.06 21.3 62.7 41.4

Masoom 6 7.84 18.5 62.5 44

Masoom 5 8.12 19.3 64.4 45.1

Ghouri 5 8.58 19.1 64.6 45.5

144

5.2.4. Conclusions

Our lab results explained the relation between the intrinsic parameters of local flour

samples and the added ingredients. The results from sophisticated lab equipments

revealed that some of the parameters showed very close relationship that how flour

would form the type of specific dough which will determine the biscuit quality. DS was

especially related to variety of flour characteristics. DDT from Farinograph, beginning of

Gelatinization from MVAG and RG/PG from Glutomatic were found to predict DS. The

absorbed water by DS was strongly related to values of WA obtained from Farinograph

and Glutomatic, because Glutomatic gives the amount of water absorbed only by the

gluten proteins while water absorption value from Farinograph includes the total amount

of water taken up by all the hydrophilic components of flour (Protein, Starch, DS, and

Pentosan etc.) plus some of the ingredients in the recipe that absorbs water such as the

sugar etc.

The results elaborated for the first time that the two values of WA from Farinograph and

Glutomatic were predictive for end quality of baked products.

145

5.3. Effect of commercial enzymes (proteases & carbohydrases) on dough rheology and

end quality of Cookie


Additives in bakery industry are vital ingredients to ease processing and to improve

quality of the products in relation to their structural diversity and its influence on dough

development. Enzymes are now a very important inclusion in the list of additives. It show

dominance because they can make specific structural changes in the dough without

disturbing other molecules that improves functional properties of the dough and the end

quality of the baked goods (Colombo et al, 2008; Hassan et al, 2013). Enzymes are

recognized as safe (GRAS) whereas many other additives are declared unsafe for human

consumption i.e. sulfites.

With variety of enzymatice and chemical treatments, flour other than the soft nature i.e.

Hard and semi hard have been used after making it soft since long time (Patel et al, 2012).

Many additives are used to convert the strong gluten network to weak network which

may include emulsifiers, iodates, sodium metabisulphite, proteolytic enzymes and that

cleave the peptide chains, disulphide bridges, tyrosine-tyrosine and glutamyl-lysine cross

linkages (Ramrez- Suarez et al, 2005).

Four commercial enzymes were used in the present study. Two proteases i.e. Biobake and

Nutrase and two carbohydrases i.e. Pentopan and Fungal Amylase were mixed in the

wheat flour sample with different concentration (30 ppm, 60 ppm and 90 ppm) in order

to get partially hydrolyzed dough polymers. The enzyme were capable to improve dough

rheology and dimensional characteristic of cookies by initiating molecular

rearrangements. The rheological behavior of dough and gluten characteristics were

evaluated by Perten Glutomatic System.

5.3.2. Material and Method:



146

5.3.2.1. Material:

Semi hard wheat flour sample was received from Johar Flour Mills Private Ltd. Karachi.

The enzymes as Nutrase (protease), Fungal Amylase (carbohydrase), and Pentopan

(xylanse) were obtained from Novozymes, Switzerland and Biobake (protease) was

purchased from Kerry ingredients & Flavors Carigaline, Ireland


The dough was prepared by mixing all ingredients as per recipe mentioned in table 27.

First emulsion was prepared by mixing all the ingredients except flour in Kenwood Mixer,

UK at a speed of 40 rpm for 1 min, and then flour was added and mixed at 25 rpm for

1:30 min to develop the dough. The dough was sheeted and cut using circular mold of 50



The dough batches (13) were produced, control without any enzyme, Biobake, Neutrase,

Fungal Amylase and Pentopan 3 batches each consisting of 30, 60 & 90 ppm.

Table 27: Recipe of biscuit for enzyme study


(gm)

Flour 500

Sugar 150

Invert Syrup 8

Vegetable Fat 120


Ammonium bi Carbonate 5

Baking Powder 1

Salt 3

Lecithin 0.5

Water 62

Egg 37.5

Enzyme as per study

147

5.3.3. Result and Discussion:


The flour sample used in the study was the same with the following composition.

Table 28: Physicochemical Parameters

Physicochemical Parameters of

flour Amount in %

Moisture 14.5

Protein 11.2

Ash 0.468

5.3.3.2. Enzyme affecting Farinograph Properties of flour

Proteases and fungal amylases showed no effect on DDT whereas DDT increased by 47%

when Pentopan was used at 60 ppm. Dough stability was also increased by Pentopan at

all the concentration (30 ppm, 60 ppm and 90 ppm) from 8.6 min to 9.8 min, 9.4 min and

9.2 min respectively. At very low concentration of 30 ppm, Fungal Amylase decreased DST

from 8.6 min to 1.5 min. Proteases showed less DST as compare to the control flour. DoS

was increased when proteases was incorporated (at all concentrations). At the

concentration of 90 ppm, Biobake showed highest DoS as 255 FU as compare to 67 FU for

control. Pentopan showed opposite character from others (Biobake, Nutrase, and Fungal

Amylase) in controlling the stability of dough.

High FQN value was achieved by Pentopan at the concentration of 60 and 90 ppm that

may be due to the hardening effect on flour.

Overall, analysis of Farinograph revealed that all the enzymes (proteases and fungal

amylase) produced soft dough whereas pentopan showed some strengthing effect on the

dough.

5.3.3.3. Enzymes affecting Micro Visco-Amylo-Graph Properties

Table 30 represented the maximum viscosity that is a significant parameter to identify the

148

behavior of starch in dough development that can be controlled by enzymes as also

revealed earlier (Debroh et al 2011). PV was decreased from 1042 BU to 855 BU, 691 BU

and 545 BU and BD viscosity was decreased from 379 to 347, 267 and 235 BU by Pentopan

at the concentration of 30, 60 and 90 ppm respectively. Rest of the enzymes didn’t

showed any significant reaction on pasting properties as mentioned in table 30. We may

conclude that higher temperature affected enzymes activity and inactivated them by

gradually denatured the structure.

5.3.3.4. Enzymes affecting Glutomatic Properties

As expected, enzymes showed variable impact on wet gluten and dry gluten content of

flour. Proteases showed significant impact as Biobake had shown the most significant

change on Gl followed by Nutrase. Biobake reacted on gluten network and decreased GI

from 91 to 57, 34 and 13 (at the concentration of 30 ppm, 60 ppm and 90 ppm

respectively). Nutrase at 90 ppm showed largest drop (from 91 to 53) in gluten index.

Biobake acted much faster than Nutrase with less quantity of the enzyme to hydrolyze

the peptide bonds as indicated in table 31. Fungal Amylase & Pentopan (carbohydrates

degrading enzymes) didn’t show any substantial impact on softening of dough, because

their substrates (starch and arabinoxylan) were not involved in forming gluten network

complex.

5.3.3.5. Dimensional Properties of the end product

Correlation of cookie factor with Proteases and Carbohydrases were significant as R2 for

Biobake, Nutrase, Pentopan and Fungal Amylase were found to be 0.886, 0.97, 0.987 and

0.83 respectively.

Proteases increased the cookie factor of biscuit as dough is softened by the degradation

of the gluten network and produce biscuit with more spread (Kara et al, 2005).

Carbohydrateses (Fungal Amylase & Pentopan) showed an increase in the cookie factor.

It may be attributed that low concentrations of enzymes reduced the starch molecular

size to a certain extent to produce spreadness in the biscuit. Biobake performed well in

producing high cookie factor at the concentration of 60 and 90 ppm than the other

enzymes. Recently similar study was conducted by Amal A. Hassan (2013) using only

149

protease at concentration max. 25 ppm.

Table 29: Enzyme affecting Farinograph Properties

Enzyme Qty

Water

Absorption

(%)

Development

Time (min)

Stability

(min)

Degree of

Softening,

ICC (FU)

Degree of

Softening

(FU)

FQN

Control 59.6±0.1 1.7±0.1 8.6±0.2 67±3.0 39±1.5 89±1.2

Bio

bak

e 3

0

pp

m 59.6±0.2 1.7±0.1 4.6±0.3 148±5.4 102±2.4 27±1.0

60

pp

m 59.6±0.3 2.0±0.1 3.6±0.2 231±3.0 164±1.6 49±2.3

90

pp

m 59.6±0.1 2.0±0.05 3.3±0.5 255±2.0 197±1.2 48±3.0

Ne

utr

ase

30

pp

m 59.6±0.2 1.9±0.1 7.7±0.2 88±2.1 48±1.1 35±2.5

60

pp

m 59.6±0.2 2.0±0.1 5.1±0.2 134±5.0 88±5.2 38±5.6

90

pp

m 59.6±0.3 1.9±0.1 4.2±0.2 191±5.5 115±2.3 38±2.1

Pe

nto

pan

30

pp

m 59.6±0.1 2.3±0.05 9.8±0.4 66±1.3 27±4.6 44±2.3

60

pp

m 59.6±0.3 2.5±0.05 9.4±0.6 73±3.0 27±2.1 103±2.4

90

pp

m 59.6±0.2 2.2±0.5 9.2±0.8 74±1.1 29±2.2 101±4.5

Fun

gal A

myl

ase

30

pp

m 59.6±0.3 1.8±0.1 1.5±0.2 139±3.2 104±5.1 24±1.2

60

pp

m 59.6±0.1 1.7±0.1 1.2±0.7 136±4.0 110±4.5 21±1.5

90

pp

m 59.6±0.1 2.0±0.1 1.4±0.4 116±5.2 91±4.8 26±2.8

Standard Deviation is indicated as ± after the mean value

150

Table 30: Enzyme affecting Micro Visco-Amylo-Graph Properties

Enzyme Qty

Beginning of

Gelatinization

(BU)

Max viscosity

(BU)

Break- down

(BU) Setback (BU)

Control 23±0.3 1042±15 379±5.1 481±8.1

Bio

bak

e

30

pp

m 24±0.5 1018±12 375±4.6 453±6.5

60

pp

m 11±0.4 1012±8 377±3.4 403±9.5

90

pp

m 21±0.5 952±20 326±2.4 400±5.7

Ne

utr

ase

30

pp

m 21±1.2 979±15 350±2.6 252±6.1

60

pp

m 18±2.1 1005±13 399±4.5 531±5.4

90

pp

m 17±1.4 973±16 355±4.1 547±2.3

Pe

nto

pan

30

pp

m 18±2.2 858±8 347±4.7 514±8.5

60

pp

m 18±1.5 691±11 267±5.2 261±5.5

90

pp

m 17±1.3 548±14 235±4.3 357±5.7

Fun

gal A

myl

ase

30

pp

m 15±1.5 987±7 317±3.1 236±6.1

60

pp

m 18±1.3 971±11 323±2.3 244±8.4

90

pp

m 17±1.8 936±8 320±4.6 389±9.7


151

Table 31: enzyme affecting Glutomatic Properties

Enzyme Qty Wet Gluten

(%)

Retained

Gluten (%)

Passed

Gluten (%)

Gluten

Index

Dry Gluten

(%)

Control 25.67±0.5 23.59±0.5 2.09±0.5 91±3 8.91±0.5

Bio

bak

e

30

pp

m

26.70±0.5 15.30±1.2 11.41±1.4 57±2 8.50±0.2

60

pp

m

27.41±1.2 9.41±2.2 18.00±1.5 34±1 8.66±0.1

90

pp

m

27.40±0.7 3.66±1.2 23.74±2.1 13±4 8.70±0.4

Nu

tras

e

30

pp

m

23.60±0.4 21.88±0.8 1.72±1.3 92±2 8.52±0.1

60

pp

m

25.55±0.5 18.86±1.4 6.69±1.0 73±3 8.66±0.1

90

pp

m

24.40±0.5 13.12±1.2 11.29±1.1 53±2 8.70±0.4

Pe

nto

pan

30

pp

m

25.91±1.2 22.67±0.7 3.24±0.1 87±2 8.53±0.1

60

pp

m

26.37±0.2 22.62±1.1 3.75±0.4 85±4 8.67±0.2

90

pp

m

25.73±0.7 21.40±1.1 4.33±0.1 83±3 8.37±0.1

Fun

gal A

myl

ase 30

pp

m

25.76±0.6 21.78±0.6 3.98±0.5 84±3 8.46±0.4

60

pp

m

26.23±1.2 21.75±2.1 4.49±0.3 82±1 8.59±0.4

90

pp

m

26.07±0.9 21.10±1.5 4.97±0.4 81±2 8.40±0.3


152

Figure 120: Proteases and Amylases on Cookies factor

5.3.4. Conclusion

Enzymes like additive played vital role as dough improver and it also had shown impact on

the end quality of the product. Enzymes showed different action on dough parameters as

higher GI value was obtained by Biobake as compared to Nutrase with little less impact on

end quality. Proteases were successful in breaking the gluten network, whereas degree of

softening was affected by both proteases and Fungal Amylase. No noticeable effect was

indicated by Pentopan. 90 ppm was found to be best concentration for altering flour

property and dough rheology.

It may be summarized that the commercial enzymes i.e. Biobake, Fungal Amylase and

Pentopan worked successfully to control the dimensional properties of biscuits. The

dough may be tailored made according to the desired end product by the use of selected

proteases and carbohydrases, their ratio and concentration.

R² = 0.886

R² = 0.9728

R² = 0.9874

R² = 0.8335

6.00

6.20

6.40

6.60

6.80

7.00

7.20

7.40

20 40 60 80 100

Co

oki

e F

acto

r

Enzyme Qty (ppm)

Biobake

Neutrase

Control

Pentopan

FungalAmylase

153

6. CHAPTER: NUTRACEUTICAL PRODUCT

6.1. Legume protein enriched biscuits and its impact on rheological

properties of dough/the end quality.


Bakery products with high nutritional profile, significant textural improvement and

excellent consumer’s acceptability have been produced in the past by partially replacing

wheat flour with various other flours from pulses. Pulses generally are the rich source of

protein (18-30%), dietary fibers (14-26%), starch (32-52%) and minerals (1- 3.5%).

Variety of bakery products have been developed by incorporating lentil flour in wheat

flour including the layer and sponge cake (Hera et al, 2012). Biscuits with pigeon pea

substitution (15%) have been produced successfully in wire cut products (Tiwari et al,

2011).The sheeted and wire cut biscuits were also prepared by substituting only 5% pea

flour (Kamaljit et al, 2010). The kidney bean flour was mixed with wheat flour even up to

15% in presence of fresh orange juice and the dough behavior was observed during mixing

(Eissa et al, 2007) which was found to be normal with slightly reduced elasticity. The

biscuits from green lentil, navy and pinto beans with acceptable end qualities were

produced with high nutritional status because of potent antioxidant activity (Zucco et al,

2011).

In view of the fact that Mash bean also known as black gram (Vigna mungo) has rarely

been substituted in bakery products. The study was undertaken to investigate the effect

of wheat flour enrichment with Mash bean flour (MBF) in order to improve the nutritional

quality of biscuits and also to see its impact on physicochemical characteristics of flour,

dough rheology, dimensional, textural and organoleptic properties of biscuits.




154

6.1.2.1. Material

The wheat flour was obtained from Masoom Flour Mill, Karachi. The Mash bean flour

(MBF) was purchased from Imtiaz Super Market, Karachi. Analytical grades

reagents/chemicals were used which were procured from the distributor of MERCK

(Darmstadt, Germany) in Pakistan, Labline Pvt. Ltd.

All samples were prepared by adding (MBF) at 0, 10, 20, 30 and 40% levels in wheat flour.




UK at a speed of 40 rpm for 1 min, and then flour was added and mixed at 25 rpm for 1:30




Table 32: Recipe of biscuits with legume


(gm)

Flour 400

Sugar 150

Sodium bi carbonate 0.5

Vegetable Fat 150


Ammonium bi Carbonate 3.5

Vanillin powder 0.5

Salt 3

Lecithin 1

Water 26

6.1.3. Result and discussion:

6.1.3.1. Physicochemical properties and SRC analysis

The various physicochemical parameters of the samples analyzed were given in table 33.

Moisture content of different substituted flour was affected negatively (R2= 0.98),

whereas substitution of MBF increased the protein content constantly (R2= 0.99) as

pulses are rich in proteins (Du et al, 2013). Recently, lentil flour was supplemented in

155

producing protein enriched wheat based biscuits for babies, children and also the bread

in developing countries (Grah et al, 2014). Lentil flour, as well as pinto -bean and navy

bean flours have successfully been incorporated in pita bread (Borsuk et al, 2012)

Ash was also increased from 0.432% to 0.813% and was almost double at 40 %

substitution showing the significant increase in mineral contents. Incorporation of flour

from pulses is related to increase the resistant starch apart from increasing the other

nutrients present in legumes (Noor et al, 2012; Shah et al, 2011).

LA-SRC was less affected (R2= 0.69) with substitution of MBF although protein content

were increased from 11% to 12.65%. This may be attributed to the quality of legume

proteins, which consisting excess of low molecular weight proteins did not absorb lactic

acid. Su-SRC, SC-SRC and W-SRC profile (table 33) were increased that was due to increase

in the swelling power of the respective hydrophilic polymers by the addition of MBF. This

may be attributed to the presence of dietary fibers in pulses and also because of the

influence of damage starch produced during milling of Mash beans (Ahmed et al, 2015;

Khan et al 2015).

Table 33: Physicochemical and SRC Analysis of substituted flour

Substitution

%

Moisture

% Ash %

Protein

%

% Retention at sieve Solvent Retention Capacity

200μm 160μm

120μm bottom

LA-

SRC

SC-

SRC S-SRC

W-

SRC

0 14 0.432 11 1.6 2.3 16.6 79.5 78.8 83.5 100.9 66.4

10 13.6 0.61 11.5 5.8 1.3 14.7 78.2 89.55 91.54 105.4 81.59

20 12.98 0.664 11.9 12.2 1.5 16.9 69.4 88.92 96.82 108.68 84.96

30 12.91 0.752 12.35 18.7 2.2 17.3 61.8 88.83 100.6 109.5 84.88

40 12.44 0.813 12.85 23.3 1.8 20.6 54.3 89.3 105 111.95 93.7

6.1.3.2. Rheological properties - Farinograph

Water absorption is the amount of water required by the flour to produce optimum

dough and is represented by the amount of water required to touch the peak at 500 BU

for the first time as indicated by Farinogram (Ram et al, 2005). The water absorption

ranged from 58.5% to 62.1% and increased with increase in substitution of MBF. It may

be due to the affinity of hydrophilic polymers present in Maash flour such as proteins,

156

dietary fiber and damage starch etc. The addition of flour from pulses consisting large

amount of protein increased the water absorption in dough (Perez et al, 2013) and in

consequences modifying the dough behavior. The substitution of lentil and small white

bean flour in production of rolls has shown the substantial changes in dough rheology, for

example Farinograph water absorption capacity and dough development time increased

while the dough stability was reduced (Kohajdova et al, 2013). Dough stability is the time

between the arrival time and departure time of the peak while touching the 500 FU line.

It was first increased more on adding 10% MBF from 7.2 to 17.0 minutes. However it

dropped gradually on further substitution of MBF (i.e. 13-8 →7.7→5.7min) and even it

was lower than wheat flour itself (7.2min).The drop in stability may be attributed to the

fact that when MBF was added first time, although the total protein increased, however

it was not enough to interfere the gluten network i.e. to penetrate between the gluten

proteins, with increase in MBF proteins, the gluten network was consequently weakened

and that decreased the stability as also reported by Kohajdova et al. (2013). FQN number

was increased from 78 to 200 due to increase in hardness induced by the components of

MBF.

Table 34: Farinograph and MVAG and Glutomatic profile of substituted flour

Substitution

% WA %

DDT

(min)

DS

(min) FQN

PV

(BU)

BV

(BU)

SV

(BU) GI WG % DG %

0 58.5 1.9 7.2 78 1305 494 569 81.75 29.6 8.85

10 61 9.7 17 166 963 366 475 94.1 19.1 6.21

20 61.5 11.9 13.8 168 931 359 416 96.95 12.2 4.25

30 61.8 13.8 7.7 194 855 338 374 99.79 9.75 3.5

40 62.1 17.2 5.7 200 725 245 332 99.96 1.83 0.68


PV, BV and SV were negatively affected (R2 = 0.929, 0.934, 0.982) by MBF substitutions.

The decrease in all the viscosities was due to the reduced amount of wheat starch which

was responsible for making paste. The MBF consists of less starch as compared to wheat

flour and also the ratio of amylose to amylopectin is different that plays the key role in

regulating the properties related to pasting.

157

6.1.3.4. Glutomatic protein profile

Gluten index, wet and dry gluten contents were reported in table 34. Both the wet and

dry gluten contents were decreased due to the substitution of MBF. The sharp decrease

in WG from the control to the sample after addition of 10% MBF then the gradual drop

showed that wheat proteins had better ability of holding the water in their gluten network

6.1.3.5. Dimensional and sensory analysis of biscuits

The significant correlation between the dimensional properties of the biscuits made from

MBF substituted flour and that of the control was not observed. It seems that components

of wheat flour and that of MBF complement each other in functional properties required

to produce dough.

Biscuits at 20% substitution were best in texture, taste, color and overall acceptability

whereas biscuits produced with above 20 % substitution of MBF were poor in sensory

analysis.

Table 35: Dimensional Properties of Biscuits

Substitution

%

Moisture

of

Biscuit

(%)

Weight

(gm)

Diameter

(mm)

Thickness

(mm)

0 0.37 8 54.9 7.8

10 0.59 8.43 54.13 7.23

20 0.8 8.1 53.9 7

30 1 8.23 54.6 7.89

40 1.21 8.23 54.64 7.4

158

Table 36: Correlation of different parameters with % substitution of MBF

Parameter R2 Parameter R2

Moisture of flour

(with and without

MBF) sample %

-0.98076

DDT (min) 0.956755

DS (min) -0.39976

% Retention at

200μm 0.997268 FQN 0.879123

% Retention at

160μm -0.03656 PV (bu) -0.92965

% Retention at

120μm 0.784261 BV (bu) -0.93422

% Retention at

bottom -0.98243 SV (bu) -0.98279

Ash % 0.97365 GI 0.884773

Protein % 0.999336 WG % -0.98099

LA-SRC 0.691398 DG % -0.9863

SC-SRC 0.987936 Moisture of Biscuit

(%) 0.999874

S-SRC 0.970131 Weight (gm) 0.254122

W-SRC 0.918766 Diameter (mm) -0.01939

WA % 0.875586 Thickness (mm) -0.05872

159

Figure 121: Sensory score of biscuit made with control and substituted flour

6.1.4. Conclusion

The incorporation of Mash bean flour in wheat flour enhanced the nutritive value of

biscuits by increasing the proteins dietary fibers and mineral contents; it also modified

the dough behavior and pasting properties of starch positively. Moreover addition of

MBF improved the texture and acceptability of the end products. The softness of the

biscuit increased due to the incorporation of MBF because the moisture contents in the

finished products increased significantly. The biscuits made from control had moisture

as 0.37% while the biscuits from 20% MBF substitution carry 1% moisture that increased

more than double as observed. The 20% substitution of MBF was found to be the optimal

addition for considering the consumer’s acceptance, texture and the bite. The MBF

substitution in biscuits will overcome the nutritional deficiencies in the diet of the

consumers in Asian countries where consumption of biscuit is higher.

0

2

4

6

8

10Color

Flavor

TasteTexture

OverallAcceptability

0%

10%

20%

30%

40%

160

6.2. Black gram flour (BGF) in cookie dough as a substitute of egg.


Egg has been included as the raw material in many food products traditionally because of

its multiple functional properties including foaming, coagulation, emulsification, water

and fat absorption etc. Egg plays role as a binding and thickening agent due to its

composition. In recent times, legumes, sharing few of above mentioned properties have

proved their place as egg replacer in baking industries for many other beneficial

properties (Des-Marchais et al, 2011; Tiwari et al, 2011; Angioloni et al, 2012). The

composite flour of legumes and wheat flour therefore produce better microstructure of

the biscuit, making it best suitable alternative for eggs during baking process (Ma et al,

2011; Kadam et al, 2012; Uhlman et al, 2014). The transformations of microstructure of

dough after egg replacement by black gram (powder) were investigated with the help of

a technique Scanning electron microscopy (SEM). The study also included the evaluation

of physical and chemical attributes of flour, rheology of the dough and the quality of the

end product (cookies) after the addition of BGF. The study was also conducted to explore

a nutritive and applied solution of egg replacement in the composition of cookies to

reduce health concerns associated with eggs and to introduce bakery products without

egg or only a small amount of egg as an ingredient.

6.2.2. Material and method



6.2.2.1. Material

Flour sample of commercial soft wheat acquired from Garibsons Pvt. Ltd, Port Qasim, and

Karachi. Black gram was purchased from Imtiaz Super Market, Karachi. Whereas rest of

the raw materials were taken from the store of English Biscuit Manufacturers Pvt. Ltd.

Karachi (they procured from different sources).

6.2.2.2. Biscuit preparation


161


UK at a speed of 40 rpm for 1 min, and then flour was added and mixed at 25 rpm for 1:30




Table 37: Recipe of BGF biscuit

Ingredients Quantity (gm)

Flour 125

Sugar 44

Sodium bi carbonate 0.5

Vegetable Fat 40


Salt 1

Water 10

Egg 5

DATUM 1


6.2.3.1. Physico-chemical quality:

Same type and quality of flour sample was utilized in the study to evaluate the impact of

other ingredients on dough formation and cookie quality. Black gram flour increased the

overall moisture content of the mixture. Whereas no significant change in protein was

reported as mentioned in table 38. Ash content was slightly increased with the addition

of increased amount of BGF. The protein content was also slightly increased when BGF

was added. As expected the Glutomatic proteins i.e. gluten index, dry gluten and wet

gluten were gradually decreased due to absence of gluten in BGF as the proteins already

present in legumes do not assemble and associate closely to produce the viscous mass.

The increase in moisture as shown in table 38 indicated better water holding capacity of

legume protein as also measured by Farinograph (table 39). BGF was found to be good

substitute of wheat flour as substitution didn’t affect significantly overall chemical

attributes of wheat flour.

The microstructure of dough (as referred by SEM) showed interactions of proteins (from

gluten and legume) with starch granules present in wheat. These interactions were

162

revealing the difference in dough structures and its formation. A continuous starch-

protein matrix in control (wheat flour without BGF) was observed which was represented

by a white line in microgram fig. 122 (a), however the structure became towards rough as

illustrated in fig. 122 (d) that was representing the incapability of proteins of BGF to link

with the wheat starch granule. It may be concluded that Protein for BGF and granules of

wheat starch form matrix which may dissociate at certain level and lead to further

increase with the further addition of proteins (BGF).

Table 38. Physico-chemical analysis of BGF

Black gm/125gm

flour)

Moisture, %

Protein, % Ash, % DG, % WG, % GI

0 14.6±0.05 10.1±0.12 0.461±0.005 7.9±0.02 25.2±0.12 93±1.0

2 14.8±0.06 10.3±0.08 0.467±0.008 7.8±0.04 24.9±0.06 92±2.1

4 14.8±0.10 10.5±0.11 0.475±0.005 7.7±0.03 24.8±0.07 91±0.6

6 15.0±0.05 10.5±0.07 0.477±0.009 7.6±0.07 24.6±0.14 87±1.2

Standard Deviation is indicated as ± after the mean value (n=3)

6.2.3.2. Farinograph Parameters

Farinograph profile i.e. WA, DST, DDT, FQN and DoS (12 min after maximum value - Dos)

was increased with the addition of black gram flour. DoS after 10 min decreased with the

increased concentration of BGF (table 39). High WA with BGF might be predicting the

possibility of intermingling of more hydrophilic biopolymers of BGF with –OH gourps of

added water. Flour strength i.e. the DDT and DST was increased by adding low amount of

the BGF (2-4 g/125 g) whereas concentration of 6 g of BGF decreased the strength of these

parameters. FQN was increased with the addition of BGF that indicated the hardening

effect of the dough. The strength in dough resulted prolonged DS, DoS and DDT. The

strength of the dough confirmed that network of protein was able to hold tiny air bubbles

firmly. Usually the albumin protein of egg plays the same role but BGF in current recipe

had successfully taken over the role of egg proteins.

163

Table 39. Farinograph Properties of BGF added dough

Black gm/125gm flour)

DDT, min WA, % DST, min DoS

ICC, FU FQN

0 1.7±0.1 59.6±0.1 08.6±0.20 67±3.0 89.0±1.20

2 2±0.8 58.5±0.4 10.5±0.22 23±0.7 112±0.77

4 6.8±0.2 59.8±0.1 11.0±0.34 16±1.0 123±0.89

6 5.5±0.3 68.5±0.2 09.0±0.70 22±0.9 126±0.50


6.2.3.3. MVAG Analysis

The all types of viscosities started increasing with the addition of BGF. The viscosities are

further increased (addition of 4 gm BGF) except few i.e. BD and PV viscosities. Whereas

each and every viscosity was decreased on 6 gm addition of BGF.

The values of breakdown and set back are true representatives of many interactions like

starch-starch, protein-protein or starch protein cross-linking. Results showed that the

dough would become more thick and viscous at the concentration of 2 gm/125 gm BGF

during heating while the mass would be less viscous at the concentration of 4 gm/125 gm

or 6 gm/125 gm. However, high viscosity at the concentration of 4 gm/125gm of BGF was

achieved on the period of cooling due to re-association of starch molecules i.e.

retrogradation (table 40).

Table 40. BG flour affecting Micro Visco-Amylo-Graph Properties.


PV, BU BD, BU SB, BU

0 1042±15 379±5.1 481±8.1

2 1220±11 436±8.1 719±4.9 4 1205±18 426±4.7 740±4.7

6 1164±10 412±3.2 646±6.0


164

6.2.3.4. Microstructure of Biscuit Dough

The roughness on surface was observed on the addition of BGF as indicated by the

encircled area. Whereas the structure of control sample (only simple wheat flour without

addition of BGF) had showed very smooth surface confirming formation of gluten matrix

and starch association only. The other images reflected the major changes on the

characteristics of surface. A complex picture was produced by the collaboration of

different starches (wheat and BGF) and their interactions with different gluten proteins.

Long white lines represented the interactions between the egg proteins, wheat starch and

gluten. The white line developed itself frequently very sharp but decreased in length

because of mixing. The smaller granules were replacing the large pieces of starch as

mentioned in fig. 122 (d), it may be due to the reason that proteins present in BGF made

matrix with shorter starch granule. The starch granules are usually intermingled in the

matrix with gluten. Bounding of starch and protein line was even shorter but was more

frequent when the concentration of BGF was increased from (b) to (d).

Figure 122: (a) control (b) 2 gm BGF added dough (c) 4 gm BGF added dough and (d)

6 gm BGF added dough respectively.

a b

d c

165

6.2.3.5. Dimensional/textural quality

The recipe of control cookie was comprised of 5 g liquid egg (whole) whereas egg was

replaced by BGF at the concentration of 2gm, 4gm and 6gm in wheat flour. 2 gm BGF

substituted flour provided best dimensional properties in comparison with controls and

other concentration too. The texture of cookies was also found to be excellent as

highlighted in table 41.

Table 41. End product quality


Diameter, mm

Weight, gm

Height, mm

Force Break, N

0 48.10±0.3 8.33±0.1 8.39±0.2 23.14±1.3

2 48.80±0.1 8.00±0.3 8.51±0.3 07.37±0.6

4 48.31±0.4 8.35±0.3 8.71±0.1 11.44±1.2

6 47.80±0.3 8.49±0.3 8.93±0.4 15.52±1.1

166

6.2.3.6. Sensory Analysis:

The factor of consumer acceptance decreased overall as BGF was increased (table 42).

The taste attribute that is the highly important and critical factor in sensory was observed

improved at the concentration of 2 gm of BGF. Bitter taste was sensed on increased

concentration of BGF. The texture of the cookie was as good as the control recipe and in

certain parameters produced better texture. Color of crumb and overall appearance of

the cookie improved in case of 2 g BGF added cookie.

Table 42. Eating quality of BGF added biscuit.


Appearance (10)

Color (10)

Crumb (10)

Taste (20)

Texture (20)

Mouthfeel (10)

Total Score (80)

0 8.5±1.5a 9.2±1.0a 8.2±0.99a 18.7±1.17a 17.8±2.01a 9.3±0.73ab 71.8

2 8.1±1.06ab 8.6±1.15a 8.9±0.97a 18.5±0.88a 18.2±1.15a 9.5±0.60a 71.9

4 7.5±1.47bc 7.8±1.2b 7.5±1.23

b 15.3±1.22

b 16.8±1.54b 8.8±0.83bc 63.8

6 7.1±1.33c 7.2±1.21b 6.9±1.39

b 14.4±0.88c 15.2±1.32c 8.6±1.09c 59.4

Mean value ± S.D with the different alphabets (superscript) within a column are

significantly different from each other. Values are calculated with Duncan method

(P<0.05). (no. of panelist = 15)

6.2.4. Conclusion

It may be concluded that BGF is one of the suitable replacement of egg in cookies. It for

sure increases the nutritional status of cookie. Concentration of 2 gm/125 gm of wheat

flour was found to be the most appropriate limit for the replacement which produced

cookies with good eating quality. Industries must look for the adoption of replacement

of egg with Mash bean flour or black gram flour to get full benefit associated with these

lentils/beans.

The nutrition and diet experts are advising strongly the consumption of legumes (daal) in

daily diet for variety of reasons. Firstly the legumes are recognized as cholesterol

lowering components while egg being rich in cholesterol has limitation in diet. The

legume starch consist resistant starch which is a beneficial dietary fiber. The dietary fibers

167

are not present in eggs. The BGF enriched biscuit after replacing egg will be economical

as eggs are the expensive ingredients of the recipe. It should also be considered that only

2 gm of BGF may replace 5 gm of egg liquid, it is an important alternative for cost

reduction. Secondly, some especial categories of consumers do not consume egg because

of religious restrictions and allergy.

The research opens the door for further research and their role in new product

development for food industries. The legume proteins hydrolysate, modified legume and

wheat starches are unique as ingredients because of their multiple functionalities, they

are the promise for high future in food products.

168

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Doctor of Philosophy In Food Science and Technology

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