ABSTRACT
Quality characteristics of flours and gluten-free cracker biscuit produced from blends of undehulled African breadfruit seed, water yam and coconut was evaluated. Composite flours and cracker biscuit were produced from different blends of undehulled African breadfruit seed flour: water yam flour: defatted coconut grits (100:0:0, 70:20:10, 60:30:10, 50:40:10, 40:50:10). The flour and cracker biscuit produced from 100 % wheat flour served as a reference sample. The samples were subjected to analysis using standard laboratory procedures. Data obtained were statistically analyzed by Analysis of Variance and mean separation by Duncan multiple range test. The bulk density of the flours ranged from 0.70 to 0.88 g/ml, oil absorption capacity ranged from 1.61 to 1.90 g/ml, water absorption capacity ranged from 1.03 to 2.56 g/ml, foam capacity ranged from 17.32 to 20.66 %, foam stability ranged from 55.60 to 64.11 %, gelatinization temperature ranged from 72.00 to 85.00 ºC and wettability ranged from 1.44 to 2.22 g/ml, with flour blends samples having higher value of bulk density, oil absorption capacity, water absorption capacity, foam stability, gelatinization and swelling index. The flour blends samples and its cracker biscuit were significantly (p<0.05) higher in antinutrient factors, amylose, amylopectin, mineral and vitamin content than the control. The proximate composition of the samples revealed that crude protein, fat, crude fibre and ash were higher in composite flour and cracker biscuit made from it, with the exception of carbohydrate and energy value. Cracker biscuits made from flour blends of African breadfruit seeds and water yam had higher weight, thickness and break strength, and lower length and width. Crackers made with 70% African bread fruit seed flour, 20% water yam flour and 10% defatted coconut grits had the least glycemic response, index and load, thus implying that it will be more suitable for consumers suffering from degenerative diseases. Results of organoleptic attributes of the cracker biscuit showed that sample 101 (cracker biscuit produced from 100% wheat flour) was rated the best in general acceptability followed by sample 106 (cracker produced from 40% African breadfruit seed, 50% water yam flour and 10% defatted coconut grits). Generally, the cracker biscuits produced from the flour blends compared favourably with the conventional cracker biscuit made from wheat flour, thus showing prospects for industrial application.
TABLE OF CONTENTS
Title page i
Certification ii
Declaration iii
Dedication iv Acknowledgements v
Table of Contents vi
List of Tables xi
List of Figures xiii Abstract xiv
CHAPTER 1: INTRODUCTION
1.1 Background of the study 1
1.2 Statement of problem 3
1.3 Justification 4
1.4 Objective
of the study 5
CHAPTER 2: LITERATURE REVIEW
2.1 Roots and tubers 7
2.2 Yam 8
2.3 Water yam 9
2.3.1 Water yam an underutilized crop 10
2.3.2 Nutritional value of water yam 11
2.3.3 Anti-nutritional factors of water yam 12
2.3.4 Processing and use of water yam 14
2.4 Legumes 16
2.5
African breadfruit 17
2.5.1
Dietary benefit of African breadfruit
seeds 19
2.5.2
Hostile to wholesome components of
African breadfruit seeds 20
2.5.3
Processing and usage of African
breadfruit seeds 23
2.6 Coconut 24
2.6.1 Nutritional value of coconut 25
2.6.2 Health benefits of coconut 26
2.6.3
Food usage of coconut 27
2.7
Overview of gluten 32
2.8
Composite flour 33
2.9
High fiber snacks 35
2.10 Crackers biscuit 37
2.10.1 Roles of ingredients for
preparation of crackers biscuit 38
2.11 Evaluation of food 40
2.11.1 Functional properties of
flour 40
2.11.2 Chemical properties of food 42
2.11.3 Amylose and amylopectin content of
food 45
2.11.4 Overview of glycemic response,
index and loads 46
2.11.4.1 Glycemic index and loads of some
commonly
consumed foods in Nigeria 47
2.11.4.2
Significance of low glycemic index and loads 49
2.11.5 Sensory
evaluation of food 49
CHAPTER 3: MATERIALS
AND METHODS
3.1
Sources of raw materials 51
3.2
Sample preparation 51
3.2.1 Production
of water yam flour 51
3.2.2 Production
of wheat flour 53
3.2.3 Production
of African breadfruit seed flour 53
3.2.4 Production of defatted coconut grits
56
3.3
Formulation of composite flour 58
3.4
Production of cracker biscuits 59
3.5 Methods of analysis 62
3.6 Determination of functional properties
of flour 62
3.6.1
Bulk density 62
3.6.2 Water
absorption capacity 62
3.6.3
Oil absorption capacity 63
3.6.4
Foam capacity and stability 63
3.6.5
Swelling index 64
3.6.6
Gelatinization temperature 64
3.6.7 Wettability 64
3.7 Determination of amylose and amylopectin
65
3.7.1 Amylose 65
3.7.2 Amylopectin 65
3.8
Determination of antinutrient factors 65
3.8.1 Tannin 65
3.8.2
Phytate 66
3.8.3
Oxalate 67
3.8.4 Saponin 67
3.9 Proximate analysis 68
3.9.1 Determination of moisture content 69
3.9.2 Determination of crude protein content 70
3.9.3 Determination of ash 70
3.9.4
Determination of fat content 71
3.9.5 Determination of crude fiber 71
3.9.6 Determination of carbohydrate 72
3.9.7 Determination of caloric value 73
3.10 Mineral analysis 73
3.10.1 Determination of phosphorus 73
3.10.2 Determination of calcium and magnesium 74
3.10.3 Determination of potassium 75
3.10.4
Determination of zinc 75
3.10.5
Determination of sodium 76
3.10.6
Determination of iron 75
3.11 Vitamin analysis 75
3.11.1
Determination of carotenoid 77
3.11.2 Determination of vitamin B1 (thiamin) 77
3.11.3 Determination of vitamin B2 (Riboflavin)
78
3.11.4 Determination of vitamin B3
(Niacin) 79
3.11.5 Determination of vitamin C (Ascorbic
acid) 80
3.11.6 Determination of tocopherol 80
3.12 Determination of glycemic index 81
3.12.1 Subject
characteristics 81
3.12.2 Test
foods/samples 81
3.12.3 Study
design 81
3.12.4 Calculation of glycemic index 82
3.12.5 Calculation of glycemic load 83
3.13 Determination of physical properties 83
3.13.1 Weight,
length, width and thickness 83
3.13.2 Break strength
83
3.14 Sensory
evaluation 84
3.15 Experimental design 84
3.16 Statistical analysis 84
CHAPTER
4: RESULTS AND DISCUSSION
4.1 Functional
properties of flour from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits 85
4.2: Proximate
composition of flours from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits
92
4.3: Antinutrient
content of flours from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits 99
4.4 Amylose
and amylopectin content of flours from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits 103
4.5 Mineral
content of from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits 105
4.6 Vitamin
content of flours from blends of undehulled African
bread fruit seed and water yam with defatted
coconut grits 111
4.7 Proximate
composition of cracker biscuits from blends of undehulled
African bread fruit seed
and water yam with defatted coconut grits 117
4.8 Antinutrient
content of cracker biscuits from blends of undehulled
African
bread fruit, water yam and defatted coconut grits
123
4.9
Amylose and amylopectin content of cracker biscuit from blends of
undehulled African bread
fruit, water yam and defatted coconut grits 128
4.10 Mineral
content of cracker biscuit from blends of undehulled
African bread
fruit, water yam and defatted coconut grits 130
4.11 Vitamin
content of cracker biscuit from blends of undehulled
African bread fruit,
water yam and defatted coconut grits 137
4.12 Physical
properties of cracker biscuit from blends of undehulled
African bread fruit and water yam with
defatted coconut grits 143
4.13 Glycemic
response (mg/dl) of the standard food (Glucose)
and crackers
biscuit at various time intervals (0 to 120 min) 146
4.14
Glycemic index and glycemic load of
cracker biscuits 149
4.15 Sensory
evaluation of cracker biscuit from blends of undehulled
African bread fruit and
water yam with defatted coconut grits 152
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 157
5.2 Recommendations 158
References 160
Appendix 186
LIST OF TABLES
3.1: Flour blends formulation 58
3.2: Recipe for
production of cracker biscuits 60
4.1: Functional properties of flour from
blends of undehulled African
bread fruit seed and water yam with defatted coconut grits 86
4.2: Proximate composition of flour from
blends of undehulled African
bread fruit seed and water yam with defatted coconut grits 93
4.3: Antinutrient composition of flour
from blends of undehulled African
bread fruit seed and water yam with defatted coconut grits 100
4.4: Amylose and amylopectin properties of
flour from blends of
undehulled African bread fruit seed and water yam with defatted
coconut grits 104
4.5: Mineral content of flour from blends
of undehulled African
bread fruit seed and water yam with defatted coconut grits 106
4.6: Vitamin content of flours from blends
of undehulled African
bread fruit seed and water yam with defatted coconut grits 113
4.7: Proximate composition of cracker
biscuit from blends of undehulled
African bread fruit, water yam and defatted coconut grits 118
4.8: Antinutrient composition of cracker
biscuits from blends of
undehulled African
bread fruit, water yam and defatted coconut grits
124
4.9: Amylose and amylopectin properties of
cracker biscuit from blends of
undehulled African bread fruit, water yam and defatted coconut grits 129
4.10:
Mineral composition of cracker biscuit from blends of undehulled
African bread fruit, water yam and
defatted coconut grits 131
4.11:
Vitamin composition of cracker biscuit from blends of undehulled
African bread fruit and water yam with
defatted coconut grits 138
4.12:
Physical properties of cracker biscuit from blends of undehulled
African bread fruit and water yam with
defatted coconut grits 143
4.13: Glycemic response (mg/dl) of the
standard food (glucose) and
crackers biscuit at various time intervals (0 to 120 min) 147
4.14:
Glycemic index and glycemic load of cracker biscuits 150
4.15: Sensory evaluation of cracker biscuit from
blends of undehulled
African
bread fruit and water yam with defatted coconut grits 153
LIST OF FIGURES
3.1: Flow chart for the production of water yam
flour 52
3.2:
Flow chart for the production of wheat flour
54
3.3: Flow chart for the
production of African breadfruit flour 55
3.4: Flow chart for the
production of defatted coconut grits 57
3.5:
Flow chart for the cracker biscuits production 61
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND TO THE STUDY
Crackers, a type of biscuits is more
or less unsweetened, salty, thin and crisp. It is known to possess very low
sugar and fat content (Uchegbu and Ishiwu, 2016). In Nigeria, crackers comprise
a mainstream cereal foods consumed by the youthful and the old. A portion of
the explanations behind such wide ubiquity are low cost compared with other
processed foods, good nutritional quality and
accessibility in various structures, differed taste and longer time span of
usability (Petrović
et al., 2016).
Generally, crackers are made from wheat
flour. Notwithstanding, numerous circumstances, for example, the fact that
wheat can't be produced in tropical nations like Nigeria because of climatic
conditions (Nwanekezi, 2013) and expanding pace of protein vitality lack of
healthy sustenance which is a significant reason for the high occurrence of
bleakness and mortality in many developing nations (WHO/UNICEF, 1998) required
research on the utilization of indigenous flours in production of baked
products like crackers.
As of late, the utilization of indigenous
flours with high fibre has picked up significance in the detailing of different
nourishment items (El-Sharnouby et al.,
2012). This may be on the grounds that dietary fibre brings down serum
cholesterol, heftiness and the solid state of the digestion tracts (Odom et al., 2013; Rehinan et al., 2014).
African breadfruit (Treculia africana) comprises a significant reserve
of basic nourishment supplements that are accessible at certain basic times of
the year when dependable wellsprings of these supplements are under development
and are rare (Nwabueze and Okocha, 2008). African breadfruit are substantial in
fibre (Okoye and Obi, 2017), protein, starch, fat, and minerals (Okorie, 2013).
Its protein helps meet lacking utilization of protein nourishment; particularly
in rustic parts of Nigeria (Uluocha et al.,
2016). The amino acid profile of African breadfruit is described by low
grouping of sulfur amino acids, for example, methionine, trytophan and cysteine
yet has high substance of lysine, arginine and histidine (Okorie, 2013). The
seeds of African breadfruit can be processed into various food items. Its flour
has a decent potential for use as a functional ingredient agent in bakery and confectionery
products due to its high water assimilation limit,
solvency, mass thickness, froth limit and fast consistency attributes (Okonkwo
and Ubani, 2012).
Water yam (Dioscorea alata) is a significant type of the dioscoreacea family developed in certain parts of Nigeria for its
huge roots with fine eatable fleshes (Ezeocha and Oti, 2013). Water yam
additionally alluded to as "winged yam" or "more noteworthy
yam" has tubers that are white, dark coloured or earthy red in shading
(Riley et al., 2006). They are known
for their high wholesome substance, with 5.69 to 8.31 % protein, 81.53 to 87.64
% sugar, 16.72 to 35.20 mg/100g vitamin C, 260 to 400 mg/100g potassium, 100 to
340 mg/100g phosphorus (Udensi et al., 2008), and 1.37 to 2.31% fibre (Ezeocha
and Ojimelukwe, 2012). Additionally, water yam is a harvest with potential for
expanded consumer request because of its low sugar content essential for
diabetic patients (Ezeocha and Ojimelukwe, 2012). Notwithstanding the
staggering dietary advantages of water yam, they are less famous when
contrasted with different assortments of yam and is regularly viewed as
nourishment for poor people (Nwike et al.,
2017).
Coconut (Cocus nucifera) is the stone of the drupes borne by the coconut
palm, a member of the monocotyledonous family Palmae. Coconut is known as the
"wonder nourishment" and is viewed as impeccable eating routine since
it contains practically all fundamental supplements required by the human body
(Rehman et al., 2004). It is named a
"functional nourishment" since it gives numerous medical advantages
past its healthful substance (Ramaswamy, 2014). Due to immense nutritional
potential of coconut such as 9 g/100g dietary fibre, 14 mg/100g calcium, 2113
mg/100g phosphorus and 356 mg/100g potassium (Sangamithra et al., 2013), there have been significant efforts to incorporate
it in different food products.
1.2
STATEMENT
OF PROBLEMS
The increasing urbanization coupled with
growing number of working mothers, have profoundly contributed to the
popularity and increased consumption of snack foods such as cracker biscuits. Wheat
flour, the main ingredient for cracker biscuits production is mainly imported
to Nigeria because of unfavourable climatic conditions for its commercial
growth. This importation places a considerable burden on the foreign exchange
reserve of Nigeria's economy (Gernah et
al., 2010; Nwanekezi, 2013).
Despite the overwhelming nutritional
advantages of water yam and its potential for economic enhancement, relatively
little research attention has been devoted to it (Nwike et al., 2017).
Due to celiac disease, consumers have
increasingly slowed down wheat foods. Celiac disease, which is an
immune-meditated genetic disorder that is triggered by consuming gluten is
estimated to affect 0.5 to 1 % of the world population, making it one of the
most chronic prevalent disorders in the whole world. Common symptoms includes
but not limited to diarrhea, fatigue and abdominal pain. Unfortunately, celiac
disease does not have a cure, but it can be controlled by removing gluten from
the diet (Presutti et al., 2007).
High
fibre diets have been reported to have numerous health benefits (Odom
et al., 2013; Rehinan et al., 2014), but despite these
benefits most people fall short of the recommended daily requirement, averaging
on 15 grams per day, far below the suggested daily fibre intake of 25 to 38
grams for adolescents and adults (Salvin, 2008).
Protein energy malnutrition is a
common problem in the poor socio-economic groups of developing countries such
as Nigeria. It is not a disease but a range of pathological condition arising
from inadequate or unbalanced diet. Consumption of inadequate food is a major
cause of the high incidence of malnutrition, morbidity and mortality in many
developing countries (WHO/UNICEF, 1998).
1.3
JUSTIFICATION OF THE STUDY
Considering the increase in prices of baked products
as a result of high cost of imported wheat, this study aims at production of
cracker biscuits from composite flours of African breadfruit, water yam and
coconut grits. This will reduce over reliance on wheat thereby saving the
Nation’s foreign exchange, creating awareness and variety. The results of this
study will also provide a baseline data on water yam utilization. This will go
a long way to diversify its use and in turn lead to its increased utilization
ultimately to ensure food security.
Frequent intake of the developed
cracker biscuits will help to lower serum cholesterol, obesity and the healthy
condition of the intestines. Dieticians’ in developing countries such as
Nigeria and individuals suffering from protein energy malnutrition, celiac
disease and diabetes will also find these cracker biscuits highly valuable.
Processing of cracker biscuits from
blends of African breadfruit seeds, water yam and coconut will encourage
farmers producing this crops due to high demand and utilization of their crops.
This will in turn put money in their pockets.
1.4
OBJECTIVE OF THE STUDY
The
main objective of this work was to produce and evaluate gluten free flour and cracker biscuits
from blends of undehulled African bread fruit, water yam and coconut.
The specific objectives were to:
i.
produce composite flours and
cracker biscuit from undehulled
African bread
fruit, water yam and coconut
ii.
determine the functional
properties of the composite flours
iii.
determine the amylose and
amylopectin of both composite flours
and cracker biscuits
iv.
determine the
anti-nutritional factors of both composite flours and cracker biscuits
v.
determine the proximate,
mineral and vitamin content of the composite flours and cracker biscuits
vi.
evaluate the glucose response, glycemic index and loads of the cracker
biscuits
vii.
evaluate the physical and
sensory properties of the cracker biscuits.
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