SOKOINE UNIVERSITY OF AGRICULTURE COLLEGE OF AGRICULTURE DEPARTMENT OF FOOD TECHNOLOGY, NUTRITION AND CONSUMER SCIENCES. BSc. FOOD SCIENCE AND TECHNOLOGY SPECIAL PROJECT REPORT TITLE: AWARENESS, ACCEPTABILITY AND KEEPING QUALITY OF LOCALLY PROCESSED COCOA BEANS FOR BEVERAGE PREPARATION NAME OF STUDENT: LUHWAGO, SHADRACK C. REG. NO: FST/D/2013/0008 A SPECIAL PROJECT REPORT SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF BACHELOR OF SCIENCE IN FOOD SCIENCE AND TECHNOLOGY OF SOKOINE UNIVERSITY OF AGRICULTURE, MOROGORO, TANZANIA NAME OF SUPERVISOR: PROF. LASWAI, HENRY
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
SOKOINE UNIVERSITY OF AGRICULTURE
COLLEGE OF AGRICULTURE
DEPARTMENT OF FOOD TECHNOLOGY, NUTRITION AND CONSUMER SCIENCES.
BSc. FOOD SCIENCE AND TECHNOLOGY
SPECIAL PROJECT REPORT
TITLE: AWARENESS, ACCEPTABILITY AND KEEPING QUALITY OF LOCALLY
PROCESSED COCOA BEANS FOR BEVERAGE PREPARATION
NAME OF STUDENT: LUHWAGO, SHADRACK C.
REG. NO: FST/D/2013/0008
A SPECIAL PROJECT REPORT SUBMITTED IN PARTIAL FULFILMENT OF THE
REQUIREMENTS FOR THE DEGREE OF BACHELOR OF SCIENCE IN FOOD SCIENCE AND
TECHNOLOGY OF SOKOINE UNIVERSITY OF AGRICULTURE, MOROGORO, TANZANIA
NAME OF SUPERVISOR: PROF. LASWAI, HENRY
JUNE 2016
ABSTRACT
The distinctive flavour of Tanzanian cocoa has recently been attracting the attention of the international
cocoa world, but still in Tanzania there is low or even no emphasis on cocoa farming in order to reach its
full potential. Objectives of this work were to sensitize the community towards use of locally processed
cocoa beans in preparing affordable drinks. This study had two sections namely; case study and sensory
evaluation aimed to test the consumer acceptability of the product. Factors relating and affecting the
growth of cocoa fruits was stipulated by observation and questionnairres in the study area. Based on the
results of this study, Most of the farmers they did not have land to cultivate cocoa, since it took about four
to five years to start harvesting after planting. This was too long times tended to bind the land, and make it
and hinder cultivation of other crops, especially for that farmer having small pieces of land. Other farmers
were not aware of cocoa farming. On the formulation of the product actually there was no clear formation
of cocoa powder during the milling and this might have been contributed by presence of high content of
lipid in the cocoa liquor. This suggests that the lipid should be extracted prior to milling in order to get
cocoa powder after grinding. The press–cake obtained is possible to be ground to easily get a cocoa
powder. This study showed that the cocoa beverage was so bitter, probably caused by incomplete drying
of cocoa beans and ineffective roasting of cocoa beans since during roasting an electrical laboratory oven
was used instead of using a roaster. The major causes for the bitterness could be due to lack of alkalization
process, which adjusts the level of acidity. Therefore, alkalization, removal of lipid and the use of roaster
should be subjects of further research for improving quality of cocoa powder.
2
ACKNOWLEDGEMENT
I would first like to thank God in each step that I make in my life because without him this study could not
be conducted. Thanks go to my parents for their psychological advice, their moral and financial support.
I wish to convey my gratitude to the Higher Education Students Loan Board (HESLB) for the sponsorship
that enabled me to pursue a BSc. in Food Science and Technology at the Sokoine University of Agriculture
(SUA) under the Department of Food Technology, Nutrition and Consumer Sciences.
I am very grateful to my supervisor Prof. Laswai, H. for his great supervision without getting tired since he
used his time to correct my mistakes.
I would like to acknowledge Mr. Stewart Mwanyika, and Sister Roza Shirima, a laboratory technician
From the Department of Food Technology, Nutrition and Consumer Sciences for their great collaboration.
Lastly, I would like to thank all students who participated in conducting sensory evaluation and all those
students who in one way or another encouraged me from the beginning to the end of this study.
3
COPYRIGHT
No part of this special project may be produced, stored in any retrieval system, or transmitted in hard copy
or electronic media or by any means without prior written permission from the author or Sokoine
University of Agriculture on behalf.
4
DECLARATION
I, Luhwago Shadrack C., do hereby declare to the Senate of Sokoine University of Agriculture, that this
special project is my original work, and has not been submitted for a degree award in any other university.
Signature……………………………………
Date…………………………………………..
SUPERVISOR:
Name……………………….
Signature……………….
Date………
5
DEDICATION
This work is dedicated to my lovely father, Mr Christian Luhwago and my lovely step mother, Elizabeth
Kayugwa for their encouragements.
Also, I dedicate this work to my elders and young brothers too, it is a long list, to mention them all by
names for their encouragement and advice.
There is nothing I can pay for taking care of me, you always showed me the greatest love than nobody else.
(Winarno,1991) .The study done by Retnowati et al. (2000) also noted that the total lipid content of
fermented cocoa beans is lower than that of unfermented beans.
15
2.1.4 Phenolic compounds
Phenolics in cocoa (Theobroma cacao) and cocoa products can be classified into three main groups:
flavan-3-ols (37%), anthocyanins (4%) and proantho-cyanidins (58%). According to Markovic et al.,
(2011) the unfermented cocoa bean contains about 120–180 g/ kg of phenolic compounds,with epicatechin,
Catechin, gallocatechin, epigallocatechin, epicate-chin-3-gallate and numerous procyanidins. The phenolic
content of raw cocoa beans differs substantially from those in cocoa powder, cocoa liquor or chocolate.
Their content and concentration depend on cocoa bean variety, degree of ripeness, processing and storage.
2.2 Processing of Cocoa Beans
2.2.1 Industrial processing of cocoa beans
A cocoa processing plant transforms cocoa beans into three main components: cocoa liquor, cocoa butter
and cocoa powder. These components can be used to make different products. Cocoa liquor is used with
other ingredients, to produce chocolate (Kaplinsky, 2004). Cocoa powder can be used as an ingredient in
almost any foodstuff. For example, it is used in chocolate flavoured drinks, preparation of tea as breakfast,
chocolate flavoured desserts such as ice cream and mousse, chocolate spreads and sauces, and cakes and
biscuits (State, 2015) Cocoa beans undergo several important steps to enhance and capture their flavour
(Fig. 2). The beans are first removed from the cocoa pod, then fermented, dried, roasted, and finally
cracked and winnowed to remove the bean shell. This produces cocoa nibs, which are ground or milled into
cocoa mass or liquor (Afoakwa, 2010).
16
Step one: Harvesting and opening of pod.
Step two :Fermentation.
Step three: Drying
Step four: Roasting
Step five: winnowing.
Fig. 2. Important Industrial steps in Processing of Cocoa (Afoakwa, 2010)
17
MILLING ALKALISATION PULVESATION
Finished products like
Cocoa powder Chocolate Cocoa liquour
Is done manually/ by using hands
Act as a critical control point, Enhances flavour development by converting sugars into acids ,banana leaves are used to cover cocoa beans, the temperature used is 55oc and can take 2 to 8 days to complete.
Sun-drying method is used, to reduce moisture content up to 5-7 %. Dry beans produce low
acidity.
Aims to remove the pathogenic residual microbes like Salmonella spp and E-coli
2.2.2 Local Processing of Cocoa Beans.
Local processing of cocoa beans is relatively similar to that of industrial processing except that there is no
alkalisation and pulvesation in local processing of cocoa beans (Refer to the figure 3 ).That is, the cocoa
beans are harvested, fermented, dried, roasted, winnowed, milled and lastly turned to cocoa powder. After
pod harvest, beans and adhering pulp are transferred to heaps, boxes or baskets for fermentations lasting
from 5 to 6 days. Heap fermentation of beans is covered with banana leaves (Afoakwa, 2010).
Fig.3. Local and necessary steps of cocoa beans processing (Afoakwa, 2010)
After fermentation, the beans are removed from the heaps or boxes and dried in the sun on raised platforms
covered with mats or on the ground until fully dried within 7–8 sunny days.
After fermentation and drying, the target for cocoa beans is approximately 6–8% moisture contents. For
storage and transport, moisture content should be less than 8% (Fowler et al., 1998). Indicators of well-
dried, quality beans are good brown colour and low astringency and bitterness and an absence of off-
flavours such as smoky notes and excessive acidity (Afoakwa, 2010), then cocoa beans is milled to get the
cocoa powder ready for preparation of the affordable drink. The appearance of the local and industrially
processed powders tend to differ as seen in Fig. 4, below,
18
Fermentation heap
Drying
Fig.4 Cocoa Powder Processed Locally and Industrial
The local processed cocoa powder as seen above in figure 4 is less darker than industrial one, thus even
the flavour of these two food item tend to differ since industrial darkening of cocoa powder increase the
flavour ( State, 2015).
2.2.3 Formulation of Cocoa drinks
Fig. 5. Preparations of Drinks from Locally Processed Cocoa Powder
19
Local processed cocoa powder Industrial processed cocoa powder
Water/ milk is boiled at 1000c
Shake until the solutes in the tea cup dissolved completely then drink.
Either sugar/ honey is added into the mixture (optional)
Tea spoon of cocoa powder is added into the above
Boiled water/milk is poured into a cup tea
2.3 Roasting, Alkalisation, Drying and Fermentation on Cocoa Beans Processing
2.3.1 Roasting
Roasting of the fermented seeds fulfils mainly two purposes, the removal of undesired compounds with
low boiling points, such as acetic acid and the formation of the typical roasty, sweet odourants of cocoa
(Hurst et al., 2011). Whole bean roasting loosens the shell, which is then readily removed in winnowing.
Prior to roasting, cocoa beans have bitter, acidic, astringent and nutty flavours. Roasting further diminishes
acidity-reducing concentrations of volatile acids such as acetic acid (Beckett, 2000; Granvogl et al., 2006;
Ramli et al., 2006) but not non-volatiles such as oxalic, citric, tartaric, succinic and lactic acids (Afoakwa,
2010).
2.3.2 Fermentation
The attractive aroma of cocoa powder is a result of both, fermentation and roasting and is considered to be
the most important with respect to flavour formation (Daniel et al., 2009). During fermentation, aroma
precursors, such as free amino acids, short-chain peptides and reducing sugars are formed from which the
typical cocoa aroma is suggested to be generated during the subsequent roasting process (Chieberle, 2008).
2.3.3 Drying
Drying, decreases acidity, astringency and bitterness in cocoa beans. The number of days required for
effective drying varies, according to the weather conditions of the area. In the forest regions moist climate
posed a great challenge during drying. In the Western Region where the atmosphere remains relatively
humid for a longer period, six (6) days while in the Ashanti Region with relatively lower humidity 4 to 5
days were enough for effective drying. In protecting the drying cocoa beans against rains, especially in the
night, farmers adopted precautionary measures. Farmers spread polyethylene material over the cocoa beans
on days when rainfall appeared to be likely (Owusu, 2015).
2.3.4Alkalisation
Alkalisation is carried out primarily to change colour but also influence flavour of cocoa powder. This
process is common for cocoa products such as drinks to enhance dispersibility, solubility or suspension in
water, in baking or coatings. The process consists of treating cocoa beans, nibs, liquor, cake or powder with
solutions or suspensions of alkali, usually potassium or sodium carbonate, other alkalis may also be
used(Afoakwa, 2010).
20
CHAPTER THREE
MATERIALS AND METHODS
3.1 Study Area
The study area involved in the collection of cocoa beans was Turiani in Morogoro region.
3.2 Materials
Pan dried cocoa seeds, sugar, bowl, laboratory oven, milling machine, tea spoon, disposable cup and plate, plain white paper, manual sieve, potable water and source of heat.
3.3 Methods of Data Collection
The data for the study were collected by means of questionnaire and observation. Structured and unstructured questions were prepared on a printed white paper. The questions were based on how cocoa beans were processed locally. Hedonic score test for the student from Department of Food Technology, Nutrition and Consumer Studies at Sokoine University of Agriculture was used to assess the sensory acceptability of formulated cocoa drink. The cocoa bean farmers that were involved were those from Turiani in Morogoro region.
3.4 Sample Preparation
Five kilograms of fermented and dried cocoa beans were milled to get a cocoa powder. Hot water with sugar in the cup were added to the obtained powder to prepare a drink followed by thorough mixing, ready for hedonic score test as in Figure 5.
Fig .5. sample preparation
21
Fermented cocoa seed
Dried using oven at 300c to reduce moisture content up to <8%
Roasted using oven at 1400c for 45min to develop colour and aroma
Winnowed
Cleaned and sorted
Milled to get cocoa granules(not powder)
3.5 Formulation of Cocoa drinks: The drink was prepared as in Fig. 6.
Fig . 6. Preparations of Drinks from Locally Processed Cocoa granules
3.6 Research Design
The cocoa drink was formulated by varying the concentration of cocoa granules and sugar (number of tea
spoons per cup) as seen in Table 10
Item No/ of tea spoons No/ of tea spoons No/ of tea spoons No/of tea spoons
Sugar 0 1 2 2
Cocoa granules 1 2 1 2
Table 1: Formulation of cocoa beverage
Thirty panellists composed of students from the Department of Food Technology, Nutrition and Consumer
Sciences participated in the hedonic test to assess the acceptability of the formulated cocoa drinks. The
parameters tested were aroma, colour, sweetness, flavour, taste and overall acceptability.
22
Water was boiled at 1000c
Thorough mixing was done in the tea cup to dissolve completely
Sugar was added into the mixture
Tea spoon of cocoa granules was added into the above
Boiled water was poured into a cup tea
Sieving was done to get a clear drink ready to use
3.6 Data Analysis
Data was analyzed using R COMMANDER and the mean scores of the parameters tested were compared
and tested for significance (p<0.05). From this comparison, conclusions were drawn as in the discussion.
23
CHAPTER FOUR
RESULTS AND DISCUSSION
4.1 RESULTS
4.1.1 Survey results
A case study on awareness, acceptability and keeping quality of locally processed cocoa beans for beverage
preparation was conducted in Turiani village in Morogoro region,involving 30 farmers who were
interviewed. The findings were as shown in the Table 2.
Table 2. Survey results conducted Turiani in Morogoro region.
Item Particulars Proportion
Farming crop Yam 15%
Maize 5%
Cocoa 50%
Pad rice 25%
None of these 5%
Awareness about cocoa farming Yes 65%
No 35%
Reasons of not cultivating cocoa Lack of knowledge and skills 35%
Lack of land 30%
Lack of capital 8%
Non profit 2%
Poor market 25%
Readiness to cultivate if there is land, skills
and market
Yes 90%
No 10%
Household income per day For cocoa farmers Above 5$
For non -cocoa farmers 1$-2$
Price of cocoa per kg Depend on the dryness level and quality of
cocoa itself
1.5$ - 2$
Farming of cocoa tree Intercropping system(banana trees and
cocoa trees)
For shadow
provision
Processing of cocoa fruits Harvesting> poding> fermentation> drying
in the sun> selling
No any value
addition
24
4.1.2 SENSORY EVALUATION RESULTS
The results of sensory evaluation were as shown in Table 3