ABSTRACT
This was based on the production of concentrate from Cocoa Pod Exudate. The proximate, minerals, vitamins, chemical, microbial and sensory properties of the concentrate were evaluated using standard methods. Data was obtained and subjected to analysis of variance and the mean was separated using Duncan’s principle range test. The proximate properties of the concentrate was obtained and it revealed that the moisture content, ash content, fat content, crude fibre, crude protein, and carbohydrate were significantly different (p<0.05) ranging from (92.70 – 90.85%), (0.74 - 0.87%), (0.61 – 1.05%), (0.88 – 0.49%), (1.02 – 0.62%), and (4.06 – 6.13%) respectively among the samples. The mineral composition of the concentrates ranged from Calcium (23.80 – 15.70), Magnesium (20.65 – 17.55), Sodium (242.00 – 268.50) and Potassium (288.50 – 273.00). The vitamin content of the concentrate ranges from Vitamin C (244.00 – 121.00 mg/100g), Vitamin B1 (0.77 – 0.63 mg/100g), Vitamin B2 (0.55 – 0.82 mg/100g), Vitamin B3 (0.00 – 0.13 mg/100g) and Vitamin A (5.35 – 0.00 mg/100g) respectively. Chemical composition of the concentrate showed that there was significant difference (p<0.05) among the samples. The sensory properties of the concentrates also shows that the level of likeness of the sensory attribute: appearance, clarity, taste, flavor, mouth-feel, and general acceptability. There were significant difference (p<0.05) in the general acceptability and Control (Pineapple Concentrate) sample was liked extremely by the panelist.
TABLE OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgement v
Table of Contents vi
List of Tables vii
List of Figures viii
List of Plates ix
Abstract x
CHAPTER 1: INTRODUCTION
1.1 Background of the study 1
1.2 Statement of problem 2
1.3 Justification of the study 3
1.4 Objective of the study 3
CHAPTER 2: LITERATURE REVIEW
2.1 Descriptive of cocoa 4
2.2 Origin and cultivation of cocoa 5
2.3 Characterization of cocoa varieties 7
2.3.1 Forastero (the robust bean) 7
2.3.2 Criollo (the rare bean) 8
2.3.3 Trinitario (the hybrid bean) 9
2.4 Nutritional composition of cocoa 10
2.4.1 Anti-nutritional composition of cocoa 12
2.4.2 Chemical properties of cocoa 12
2.5 Health benefits of cocoa 13
2.5.1 Cocoa and cardiovascular diseases 13
2.5.2 Effects on the neurons 14
2.5.3Ant-tumour effect 14
2.6 Uses of cocoa 15
2.6.1 Beverages 15
2.6.2 Powders and extract 16
2.6.3 Fruit fermentation 16
2.7 Products of cocoa 16
2.7.1 Cocoa mass or liquor 17
2.7.2 Cocoa butter 17
2.7.3 Cocoa powder 18
2.7.4 Cocoa juice 18
2.7.5 Chocolate (un-refined local chocolate) 18
2.7.5.1 Processing of chocolate 19
2.7.5.2 Types of chocolate 19
2.8 Juice concentrate 19
2.8.1 Types of juice concentrate 20
2.8.1.1 100% fruit concentrate 20
2.8.1.2 Concentrated fruit cocktail, punch, or beverage 20
2.8.1.3 Powdered juice concentrates 20
2.8.2 Production method of juice concentration 21
2.8.2.1 Thermal evaporation under vacuum 21
2.8.2.2 Freeze concentration 22
2.8.2.3 Membrane processing 23
2.8.2.4 Combined UF and RO 24
2.8.3 Health benefits of juice concentrate 24
CHAPTER 3: MATERIALS AND METHODS
3.1 Source of materials 25
3.2 Sample preparation 25
3.3 Proximate analysis 29
3.3.1 Moisture determination 29
3.3.2 Determination of crude protein 29
3.3.3 Crude fibre determination 30
3.3.4 Ash content determination 30
3.3.5 Determination of fat content 31
3.3.6 Total carbohydrate determination 31
3.4 Minerals determination 32
3.4.1 Calcium determination 32
3.4.2 Sodium determination 32
3.4.3 Magnesium determination 33
3.4.4 Potassium determination 34
3.5 Vitamins determination 34
3.5.1 Determination of vitamin A (Retinol) 34
3.5.2 Determination of vitamin B1 (Thiamine) 35
3.5.3 Vitamin B2 determination (Riboflavin) 35
3.5.4 Determination of vitamin B3 (Niacin) 36
3.5.5 Vitamin C (Ascorbic acid) 36
3.6 Chemical determination 37
3.6.1 Determination of hydrogen ion concentration (pH) 37
3.6.2 Determination total titratable acidity (TTA) (% lactic acid) 37
3.6.3 Determination of total soluble solids (brix) 38
3.6.4 Determination of total sugar 38
3.7 Microbial determination 38
3.7.1 Materials 38
3.7.2 Procedures 38
3.7.3 Inoculation 39
3.7.4 Incubation 39
3.7.5 Microscopy 39
3.8 Sensory evaluation 40
3.9 Experimental design 40
3.10 Statistical analysis 41
CHAPTER 4: RESULT AND DISCUSSION
4.1 Proximate compositions on cocoa concentrate 42
4.2 Mineral compositions on cocoa concentrate 45
4.3 Vitamin compositions on cocoa concentrate 47
4.4 Chemical compositions on cocoa concentrate 49
4.5 Microbial characteristics on cocoa concentrate 52
4.6 Sensory properties on cocoa concentrate 54
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 57
5.2 Recommendation 57
References 58
Appendix 66
LIST OF TABLES
Table 2.1: Types of evaporators used for fruit juice concentration 21
LIST OF FIGURES
Figure 3.1: Flow chart for the production of cocoa concentrate 26
Figure 3.2: Flow chart for the production of pineapple concentrate 28
LIST OF PLATES
Plate 1: Pictures of raw materials 25
Plate 2: Pictures of raw materials 27
Plate 3: Pictures during production of cocoa pod in food processing lab 41
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Cocoa (Theobroma cacao) is a tropical evergreen tree of the family malvaceae grown for its edible seeds. Cocoa pod husks contain 3% to 4% potassium on dry basis. Pod husks ash has been used to make soap in Ghana and Nigeria. (Jayeola et al., 2019). Cocoa (Theobroma cacao) is grown in a land between 20 ºN and 20 ºS of the equator.
Cocoa (Theobroma cacao) is primarily grown for its bean to be further processed to obtain the cocoa powder and butter. When the bean is removed from its fruit, the left over called the pod constitutes about 75% of the weight of the whole fruit (Hermann and Valentin, 2010).
Apart from cocoa bean as by-product, some cocoa by-products include; cocoa shell, cocoa juice, and cocoa butter. Cocoa can be used for other purposes aside from human consumption such as; animal feeds, natural manure, soap production etc. Cocoa and its derivatives can be beneficial to us in several ways such as neuro-protective, immune regulation, anti-diabetic, anti-oxidant, anti-inflammatory and anti-obesity etc. Cocoa is a cash crop which is perennial in nature, of which cocoa powder is a product obtained from cocoa seeds (Hermann and Valentin, 2010). The cocoa powder contains various nutritive values which provide a mixture of carbohydrates, fats, protein, fiber, minerals and vitamins. The cocoa pulp is simply the juice and the fruit solids of the tropical cocoa fruit. Cocoa pulp contains 80 - 90% water, 10 - 15% sugar, 0.4 - 0.8% citric acid, 1% pectin and other constituents in minute quantity. . Cocoa pulp extracted from fresh cocoa beans using 'Cocoa Depulper' is suitable for conversion into economic products (Jayeola et al., 2019).
Fruit juices are made from pure filtered fruit juice with nothing added. Sodium benzoate can be added as a preservative to extend the shelf life, but this is not essential. Properly pasteurized juice has a shelf life of several months (FAO, 2015). Most fruits can be used to make juice. The most popular ones are pineapple, orange, mango, grapefruit and passion fruit (FAO, 2015).
A concentrate is a form of substance which has had the majority of its base component (in the case of a liquid; the solvent) removed. Typically, this will be the removal of water from a solution or suspension, such as the removal of water from fruit juice (Wikipedia, 2015).
In fruit juice industry, concentration refers to a process of separation of water (or any other solvent) from the solids of the pulp, juice, and extract by making use of the three basic methods i.e. evaporation, freezing and membrane technology. This, not only provides microbial stability, but also reduces the costs of packaging, transportation and storage of pulps and juices by reducing the bulk of the material. Concentrated juice contains far less water than normal, or “not-from-concentrate” forms of juice (Sharma, 2021). One benefit of producing a concentrate is that of reduction in weight and volume for transportation, as the concentrate can be reconstituted at the time of usage by the addition of the solvent (Azam-Ali, 2008).
Cocoa juice is 100% pressed juice gotten from the sweet fruit of cocoa. Cocoa powder has often been used as a substitute in cooking to give an item the flavoring of chocolate. Cocoa liquid extract offers that same ability in a highly concentrated form (Mobhammer et al., 2005a). This makes it easy to store and easy to use because less is more when it comes to this extract. Rather than tubs of cocoa powder, small bottles of cocoa liquid extract can offer the same amount of flavor. Less is added of the extract recipe too, so there is less mess to clean up later.
1.2 STATEMENT OF PROBLEM
Cocoa pod exudates are very rich in nutrients and health promoting benefits (Pszczola, 2003) while serving as a nourishing beverage (Menrad, 2003). These exudates have high moisture content and are easily contaminated by microorganisms that lead to spoilage. There is a need to improve the shelf life of the exudates while retaining the qualities.
1.3 JUSTIFICATION
Microbial spoilage and low shelf life of cocoa and its products are consequence of high moisture content. Concentration of liquid products will go a long way in improving its shelf life as the moisture reduces (Mobhammer et al., 2005c). This could be applied in cocoa pod exudates which will be useful in promoting its utilization in diverse industrial applications. Also, compared to chocolate, cocoa liquid extract has a creamier flavor that is milder. It is a great substitute for chocolate flavoring for those that have a milder palate. It will add to the existing literature to any researcher who would successfully delve into this area.
1.4 OBJECTIVE OF THE STUDY
The main objective of the study was to produce a concentrate from cocoa pod exudate. The specific objectives were to;
i. extract pulp from cocoa and concentrate the cocoa pulp juice
ii. determine the proximate composition of the cocoa pulp concentrate
iii. determine the mineral, vitamin and chemical compositions of the cocoa pulp concentrate
iv. determine the microbial quality of the cocoa pulp concentrate
v. determine the sensory properties of the cocoa pulp concentrate
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