EFFECT OF SKY FRUIT’S SEED POWDER ON OXIDATIVE STABILITY OF MUFFIN

EFFECT OF SKY FRUIT’S SEED POWDER ON STABILITY OF MUFFIN

AMIR BIN MOHD AISHA NUDDIN

BACHELOR OF SCIENCE (Hons.) FOOD SCIENCE AND TECHNOLOGY

FACULTY OF APPLIED SCIENCES UNIVERSITI TEKNOLOGI MARA

JANUARY 2012

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ACKNOWLEDGEMENT

In the name of Allah, the Most Merciful, the Most Gracious and the Most Beneficent.

First of all, syukur Alhamdulillah to Allah the almighty for His consent for making this study a success. During the completion of this thesis, there was a full support shown by several people.The success of this project has depended on many beside myself.

I wish to express my gratitude to my project supervisor Dr. Aishah Bujang for the guidance, assistance and valuable comments throughout the study.

I would also record sincere gratitude and appreciation to all Food Technology lecturers, whose encouragement and optimism have given me the urge and strength to complete this project

A special note of thanks goes to all laboratory assistance Mrs. Norahiza, Miss Nor Shuhada, Mr. Fadzli, Miss Hariyah and Mrs Siti Marhani for their cooperation during the laboratory analysis. I was grateful to my course mates and friends for their support, suggestion and advices. Thanks are also due to numerous people who contributed directly or indirectly in making this project successful.

Last but not least, the heartiest thanks for my parents and family for their support, encouragement and perseverance.

May Allah bless all of you

Amir b Mohd Aisha Nuddin

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TABLE OF CONTENTS

Page

ACKKNOWLEDGEMENT iii TABLE OF CONTENTS iv LIST OF TABLES vi LIST OF FIGURES vii LIST OF ABBREVIATIONS viii ABSTRACTS ix ABSTRAK x CHAPTER 1 INTRODUCTION 1.1 Background of study 1 1.2 Problem statement 2 1.3 Significant of study 3 1.4 Objective of study 4

CHAPTER 2 LITERATURE REVIEW 2.1 Sky Fruits 5 2.2 Phenolic compound 8 2.3 Flavonoids 8 2.4 Saponins 9 2.5 Quality of muffin 10

CHAPTER 3 METHODOLOGY 3.1 Material 15

3.1.1 Raw material and chemicals 15 3.2 Preparation of sky fruit sample 15 3.3 Preparation of muffin 16 3.4 Total phenolic content 18 3.5 Saponins determination 19 3.6 Lipid Oxidation Test 19

3.6.1 Acid Value Test (AV) 19 3.6.2 Determination of Peroxide value (PV) 20 3.6.3 Rancimat 20

3.7 Sensory Evaluation 20

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CHAPTER 4 RESULT AND DISCUSSION 4.1 Total phenolic content (TPC) of sky fruit seeds 21 4.2 Saponin Content 22 4.3 Acid Value (AV) of muffins 23 4.4 Peroxide value (PV) of muffins 24 4.5 Rancimat 27 4.6 Sensory Evaluation 28

CHAPTER 5 CONCLUSION AND RECOMMENDATION 5.1 Conclusion 30 5.2 Recommendation 31

CITED REFERENCES 32 APPENDICES 35 CURRICULUM VITAE 36

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LIST OF TABLES

Table Caption Page

2.1 Quality standards of muffin 13

2.2 Problems and their causes 14

3.1 Formulation of muffins 18

4.1 Total phenolic content of sky fruit’s seed 21

4.2 Saponin content in 100 g sky fruit’s seed 22

4.3 Induction period of muffin’s oil containing 27

Sky fruit’s seeds in rancimat method at 120˚C

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LIST OF FIGURES

Figure Caption Page

2.1 Sky fruit’s tree 7

2.2 Sky fruit’s seeds 7

3.1 Flowchart of analysis design 16

4.1 Acid values of muffin during 12 days storage 24

4.2 Peroxide values of muffins during 12 25

days of storage

4.3 Overall acceptance of 25 panelists on 28

different muffin formulation

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LIST OF ABBREVIATIONS

Etc : et cetera

ppm : Part per million

g : Gram

mL : Milliliter

nm : Nano meter

M : Molar

TBA : Thiobarbituric acid number

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ABSTRACTS

EFFECT OF SKY FRUIT’S SEED POWDER ON OXIDATIVE STABILITY OF MUFFIN

The aim of this study is to determine the effect of sky fruit’s seed on stability of muffin. In this study the seeds of sky fruit or Swietenia macrophylla were used to analysed its effect on the quality of muffin. The sky fruit’s seed were dried slightly and ground into a fine powder form. The powder was analysed for its total phenolic and saponin content. Analysis of oxidative stability was done on muffins added with the sky fruit’s seed powder and acceptance test was also been done on the muffins. For the total phenolic content of the seed’s powder analysed by using spectrophotometer and gallic acid standard curve. The result shows that the total phenolic compound in the powder was 482.47 + 47.12 mgGAE/100 g. Saponin content was analysed using gravimetric method and the result obtained was 418.62 + 68.71 mg/100 g saponin. Four formulation of muffin with no powder added as control, 50 ppm, 100 ppm and 500 ppm seed’s powder was prepared. Acid value and peroxide value test been done for 12 days and rancimat test also been done on extracted muffin’s oil. For all the analysis, the highest oxidative stability in the 500 ppm muffin. Acceptance test on the taste of muffin was conducted on 25 panellist shows that controlled formulation with no seed’s powder added receive the highest acceptance test. For 50 ppm muffin, 20% of the panellists was able to detect the bitterness of the sky fruit powder in the muffin. Studies show that sky fruit’s seed powder have positive effect on oxidative stability but its bitterness affects the muffin taste hence reduce the suitability of the powder to be used in food product.

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ABSTRAK

KESAN SERBUK BIJI BUAH TUNJUK LANGIT TERHADAP KESTABILAN OKSIDATIF MUFIN

Kajian ini dijalankan untuk menilai jumlah kandungan komponen aktif di dalam serbuk biji buah tunjuk langit iaitu fenolik dan saponin. Analisis kestabilan oksidatif telah dijalankan ke atas minyak yang diestrak dari mufin. Seterusnya analisis penerimaan panel dijalankan untuk melihat tahap penerimaan panel-panel terhadap mufin yang berlainan formulasi menggunakan serbuk biji tunjuk langit. Biji buah tunjuk langit di hancurkan sehingga menjadi serbuk. Untuk menentukan jumlah kandungan fenolik yang terkandung, spektrofotometer telah digunakan dengan menganalisis lengkung piawai asid gallic. Didapati jumlah kompaun fenolik adalah sebanyak 482.47 + 47.12 mgGAE/100 g. Kandungan saponin telah diuji dengan menggunakan kaedah gravimetrik dan didapati kandungan saponinnya adalah sebanyak 418.62 + 68.71 mg/100 g. Empat formulasi muffin digunakan iaitu kawalan tanpa serbuk biji tunjuk langit, 50 ppm, 100 ppm, dan 500 ppm serbuk biji tunjuk langit. Nilai asid, nilai peroksida dan ujian racimat dilakukan untuk mengkaji kestabilan oksidatif estrak minyak dari mufin tersebut. Untuk ketiga-tiga ujian tersebut, kestabilan oksidatif paling tinggi dapat dilihat pada minyak dari formulasi mufin yang mempunyai 500 ppm kandungan serbuk biji tunjuk langit. Ujuan tahap penerimaan telah dijalankan ke atas 25 panel menunjukkan mufin kawalan tanpa serbuk biji tunjuk langit menunjukkan tahap penerimaan yang paling tinggi. Tahap penerimaan mufin berformulasi 50 ppm menunjukkan sedikit kesan terhadap kadar penerimaan. 25% panelis dapat mengecam rasa pahit didalam mufin namun pada kadar yang masih diterima. Kajian menunjukkan serbuk biji buah tunjuk langit mempunyai kesan positif terhadap kestabilan oksidatif buah tunjuk langit tetapi rasa pahit buah tunjuk langit yang terkesan pada mufin mengurangkan kesesuaian penggunaannya di dalam produk-produk.

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CHAPTER 1

INTRODUCTION

1.1 Background of study

Plant such as herbs have been used as traditional medicine long time ago

all over the world. Many herbs and local plant can be used to maintain our

health. Sky fruit has been used for long time ago to regulate blood sugar,

strengthen stomach, heart, lungs, liver, spleen and much more. In Malay,

sky fruit is known as “tunjuk langit” because the fruit pointed up to the

sky. Scientific name for sky fruit is ‘Swietenia macrophylla king’. This

unfamous kind of herb come with two important active ingredient found in

this fruit which are flavonoids and saponins (Seok et al., 2009).

Fats are composed of glycerol that is chemically combined with three

molecules of fatty acids. The fatty acids that are attached to the glycerol

molecule can be saturated, unsaturated and polyunsaturated. Each

particular fat has its own unique combination of fatty acids and, therefore,

its own physical and chemical properties. Saturated fatty acids are very

stable because they contain no double bonds between the carbon atoms in

the chain. However unsaturated fats (fats with double bonds) are subject to

a variety of reactions. Monounsaturated fatty acids have one double bond

while polyunsaturated have up to six double bonds and are the least stable

of the fatty acids. These double bonds are the most reactive sites on the

fatty acid chain and are easily attacked by oxygen, hydrogen, and

enzymes. Each of these attackers produces a different result.

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Production of free radicals or reactive oxygen species (ROS) during

metabolism and other activities beyond the antioxidant capacity of a

biological system gives rise to oxidative stress. Oxidative stress is one of

the factors for heart diseases, neurodegenerative diseases, cancer and in the

aging process. There are increasing evidence that oxidative damage plays a

role in the development of chronic, age-related degenerative diseases, and

that dietary antioxidants are needed in lowering risk of the disease.

Antioxidants are the substance needed in low concentrations that can act to

delay or retard the oxidation of fat. Apart from their role in health benefits,

antioxidants are also been added in foods to retard or delay oxidation of

food, initiated by free radicals formed due to exposure to environmental

factors such as air, light and temperature. Most of the antioxidants are

manufactured synthetically such as BHT and BHA. The main disadvantage

with the synthetic antioxidants is the side effects when taken in vivo. Strict

governmental rules regarding the safety of the food has necessitated the

search for natural antioxidant as food preservatives (Praveen and Awang,

2007).

1.2 Problem statement

Nowadays food products are becoming more complex and contain high

nutrients to provide energy for our daily activities. The main nutrient that

relates to the source of energy is lipid or commonly known as fats or oils.

Although lipids are needed in our food as it gives a lot of benefits, it also

has risk that comes with it. Chemical and enzymatic activities will caused

lipid breakdown, colour, odour, flavour, and texture changes (Kelly et. al.,

2002). Synthetic antioxidant, like BHA (butylated hydroxyanisole) and

BHT (butylated hydroxytoluene), are largely used in food industry and are

included in human diet. However, in recent years the use of

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natural antioxidants has been promoted because of concerns regarding the

safety of the synthetic antioxidants (Moure et. al., 2001). Natural products

from plant sources have potentials of becoming food preservatives.

According to Monica et. al. (2010), in food science, antioxidants are very

important in that they act preventing lipid oxidation in food and decreasing

the adverse effects of reactive species (ROS: reactive oxygen species;

RNS: reactive nitrogen species) on normal physiological functions in

humans. Widely distributed in the plant kingdom and abundant in our diet,

polyphenols are among the most studied classes of antioxidants (Liu,

2004).

1.3 Significant of study

This research is carried out because of the antioxidant and antimicrobial

agent that contained in sky fruit may have high potential to be

commercialised as a food additive. However, there still lack of research

had been done on Sky Fruit, even though it has been known to have

tendency to act as antioxidant or preservative. There have been studies on

the health effect of the fruit to our body but still no reseach on using it in

to prolong shelf life of the food itself.

In this country, large area of forest that contain many trees that have

secrets that still not been studied. As for example this sky fruit tree usually

used as timber to produce furniture and other things. Less people know the

benefit of this fruit. This study will provide new and worth information

about preservation properties of sky fruit. Moreover, the information can

be used as a reference for other researcher and manufactures that are

interested on sky fruit ability. This research activity also will contribute to

new or renewed public interest worldwide in herbal medicine and arise

health conscious in food intake.

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1.4 Objective of study

The objective of this study are:

1. to determine saponin and total phenolic content in sky fruit’s

seed.

2. to evaluate the effect of Sky Fruit’s seed powder on the

oxidative stability of muffin.

3. to determine consumer acceptance of muffin incorporated with

sky fruit’s seed powder.

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CHAPTER 2

LITERATURE REVIEW

2.1 Sky fruits

Herbs have been used for many centuries ago to maintain health and also

been used in enhancing the flavour, colour and aroma and to improve

physical and chemical characteristics of food. They have also been known

for their antioxidant and antimicrobial agent action on our body and food

products.

Our rain forest has thousand kinds of plant that are potential to act as

herbs. One of them is Swietenia macrophylla King or Big leaf Mahogany.

It is a tree from the family of Meliaceae. This tree is widely distributes

native to Mexico, Central and northern South America. It also have

extensively been planted mainly in Southern Asia and the Pacific and also

in the West Africa.

The fruits of mahogany also been known as “Sky fruit” or “Tunjuk Langit”

in Malays language that means “pointed to the sky”. This is because the

fruits are pointed to the sky and located at the end of the shoots. The fruits

have 5 segments that are about 15 cm long, greyish brown in colour and

have smooth woody outer skin that is 5 – 7 mm thick. When they are ripe

and dry, the fruits will split open from their base and disperse their seeds

by wind. There are 35 – 45 seeds in every fruit. The seed is brown in

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colour and 7.5 – 15 cm long with extensive air space like a wing. There are

1800 to 2500 seeds in 1 kg of them.

The seed has been used as a folk medicine in Malaysia for treating diabetes

and high blood pressure and also have a lot of healing effects. The active

ingredients with antioxidant and antimicrobial in the seed of sky fruits are

contributed by flavonoids and saponins (Seok et. al., 2009).

The first discovery of sky fruit for medication was by Doctor Larry

Brooks, a biochemist in 1990. After that, flavonoids and saponins has been

extracted from sky fruit to be used extensively (Eka, 2007).

Sky fruit’s seed also was found to be effective against diabetic rats.

Subsequent work was carried out to isolate novel antidiabetic molecule

from S. macrophylla seeds and found that switenia at the dose of 25 and 50

mg/kg body weight significantly lowered fasting blood glucose level of

type 2 diabetic in a dose dependant manner. Treatment with switenia

significantly lowered the elevated cholesterol and triglyceride levels and

improved liver glycogen level near to its normal status in a dose dependant

manner when compared with diabetic control group.

Methanolic extract of the seed also contain phenol and flavonoid which

give antioxidant activity in vitro. The extract has potent antioxidant

activity against free radical scavenging activity (DPPH), xanthine oxidase

inhibition (XOI), hydrogen peroxide scavenging activity (HPSA) and

ferric-reducing antioxidant power (FRAP) assays (Mayur et.al., 2011).

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Figure 2.1: Sky fruit’s tree

Source: Lemmens

Figure 2.2: Sky fruit’s seeds

Source: Steve (2011)

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Sky fruit’s tree

mens (2005)

Sky fruit’s seeds

Source: Steve (2011)

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2.2 Phenolic compound

Phenolics are characterised by at least one aromatic ring (C6) bearing one

or more hydroxyl groups (Michalak, 2006). Plant phenolics are known

group of natural antioxidants. They consist mostly of phenolic acids,

flavonoids, anthocyanins and their glycosides. High content of phenolics

are found in spices, tea leaves, roasted coffee and cocoa beans, and in red

wine. Phenolic antioxidants react with free lipidoxy or lipidperoxy free

radicals, that may prevent further autoxidation. The inhibition of lipid

autoxidation is important not only in foods storage or heating, but also to

reduce the oxidation of lipids after been absorbed in our body.

Phenolic compounds may be found widely in seeds and other parts of the

plant. Most seeds contain large amounts of polyunsaturated oils and

phenolic antioxidants necessary to protect polyunsaturated fatty acids in

oil against autoxidation that may occur to the seed (Pokorny, 2008).

According to Boskou (2006), the ability of certain classes of plant phenols

such as flavonoids (also called polyphenols) to bind to proteins. Flavonol–

protein binding, such as binding to cellular receptors and transporters,

involves mechanisms of polyphenols which are not related only to their

direct activity as antioxidants. Besides, this compound also needed in

stabilisation of edible oils, protection from off-flavours formation and

stabilisation of flavours

2.3 Flavonoid

Flavonoids are plant secondary metabolites widely distributed in the plant

kingdom, and can be subdivided into six classes: flavones, flavanones,

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isoflavones, flavonols, flavanols, and anthocyanins based on the structure

and conformation of the heterocyclic oxygen ring of the basic molecule.

Flavonoids are phenolic substances isolated from a wide range of vascular

plants, with over 8000 compounds are known. In plants, they may act as

antioxidants, antimicrobials, photoreceptors, visual attractors, and feeding

repellants. Many studies shows that flavonoids may perform variety of

biological activities, such as antiallergenic, antiviral and antiinflammatory.

However, most of the interest is on the antioxidant activity of flavonoids,

which is due to their ability to reduce free radical formation and to bind

with free radicals. Many studies has been conducted in the past years on

the capacity of flavonoids to act as antioxidants in vitro, and important

structure-activity relationships of the antioxidant activity have been

established.

2.4 Saponin

Saponins are synthesised from evalonic acid via the isoprenoid pathway

and are derived from triterpenoid or steroid cyclisation products of 2,3-

oxidosqualene. Saponins are differentiate by their surfactant properties and

give stable, soap-like foams when shaken with aqueous solution. Many

compounds of this saponins family are being used commercially for a

variety of purposes including as drugs and medicines, precursors for

hormone synthesis, adjuvants, foaming agents, sweeteners, taste modifiers

and also including in the cosmetics. Many saponins have potent

antimicrobial activity, and this make the natural role of these molecules in

plants is likely to protect against attack by potential pathogens (Anne,

2003).

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Saponins are steroid or triterpenoid glycosides, common in a large number

of plants and plant products that are so important in human and animal

nutrition. Several biological effects have been ascribed to saponins. Most

research has been carried out in the membrane-permeabilising,

immunostimulant, hypocholesterolaemic and anticarcinogenic properties

of saponins and they also have been found that they may have significantly

effect in the reproduction in animals. These structurally diverse

compounds have also been studied in killing protozoa and molluscs, to

have an effect on cold blooded animals, also to have the analgesic,

antioxidant activity, to impair the digestion of protein, to cause

hypoglycemia and to act as antifungal and antiviral agents (Sapna et. al.,

2009).

Although the study on plant saponins started in the 1970s, only recently

they have received an increasing attention in consideration of the

involvement of saponins in important biological processes and of their

ability to act as natural drugs in many diseases. Saponins isolated from

onion and garlic proven to act as antifungal, antitumor, cytotoxicity, blood

coagulability, anti-spasmodic and cholesterol lowering effect. Most

saponins possess a variety of bioactivities and they are among the major

effective components in nutraceutical products (Corea et. al., 2005). It also

been used for treatment of hepatitis, gastritis and bronchitis. Its infusion is

used as expectorant and diuretic (Nihal et. al, 2008).

2.5 Quality of muffin

The excellence of a muffin depends upon its lightness, texture, colour and

taste. Muffin is made light by the enlargement of the cells in the muffin

batter and this is accomplished in two ways. First, by the expansion of air

when heated during baking. The cool air in the batter is enclosed by the

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beating of the batter, or the eggs. The expanding of the enclosed air

bubbles puffs up and expands the batter: the heat also bakes the muffin,

making the walls of the cells rigid, so that they retain the structure of a

sponge.

The other method of enlarging the cells of the muffin batter is by the

evolution of carbon dioxide, a harmless gas which fills the cells and

expands when heated during the baking of the muffin. Carbon dioxide is

the gas in the bubbles given off by baking powder when it is wet and

heated. The action of cream of tartar on soda also gives off carbon dioxide.

This lightness of a muffin is greatly affected by the kind of flour used.

Flour not made expressly for use in muffin baking is rich in gluten,

an excellent quality for bread, but detrimental for muffin baking. Gluten is

a tough, rubbery substance that makes difficult the expansion of the cake

batter, because the heated air or evolved gas bubbles, is not active enough

to overcome this strong rubbery gluten. This prevents the muffin having a

fine grained texture, that is fluffy and light.

Flour with a yellowish or greyish colour does not give the beautiful and

creamy white colour that goes far towards making a muffin more

palatable. Bread flours have this fault. The delicacy of taste and flavour is

an extremely important factor, for the dainty quality of a muffin must not

be dominated by the use of strong and coarse flour. Usually, to maintain

the flavour of a muffin is by preserving the fats and oil within it from

oxidation process. Trindade et. al.,(2009) has been encouraged the food

industry to increase their efforts to develop products targeting or

maintaining low levels of trans-fatty acid and to replace synthetic

antioxidants with natural antioxidant. Study also been carried out the used

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of on using natural antioxidants against changes on fatty acid profile and

lipid oxidation caused by irradiation process in food preservation. Because

chocolate in muffin contains cocoa butter, it will eventually become rancid

as other fats do. In ideal conditions, chocolate with low milk solids content

will last longer than those with milk solids which tend to go rancid more

quickly.

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Table 2.1 Quality standards of muffin

Appearance Texture Flavour

Top

Cauliflower-like, rough

and pebbled

Thin; slightly rounded

Exterior

Golden brown

Uniform size and shape

Interior

Distinctive of ingredients

Gas holes

Medium and

evenly distributed

Cell walls

Tender

Medium

Bland to slightly

sweet

Source: Sandra (2009)

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Table 2.2: Problems and their causes Appearance Texture Odour

Peaked top

Inaccurate measuring

Too much flour; too much

batter in pan or too small pan

Overmixing

Smooth, dull surface

Overmixing

“Waxy crust”

Too much egg

Uneven mixing

Tough coarse texture

Overmixing

Inaccurate measuring (too

much flour)

Tunnels

Overmixing

Batter too deep

Off flavour

Inaccurate

measuring

Rancid fat

Source: Sandra (2009)

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