ABSTRACT
The study elucidates the production and quality evaluation of bread from blends of cocoyam corms, soy bean and wheat flours. The flours were prepared using wheat, cocoyam and soybean. Five samples were used such as sample A (100% wheat flour ), sample B (90% wheat flour and 10% cocoyam/soy flour) sample C (85% wheat flour and 15% cocoyam /soy flour) sample D (80% wheat flour and 20% cocoyam /soy flour) and sample E (75% wheat flour and 25% cocoyam /soy flour). The results showed that the maximum content of moisture, ash, crude fat, crude fibre, crude protein and carbohydrate recorded in these samples were (28.80%, 2.50%, 9.50%, 1.70%, 14.70% and 50.75%)respectively, with a minimum content of (26.60%, 1.60%, 8.60%, 0.80%, 9.45% and 45.00%) respectively. The maximum concentration of minerals; Ca, Mg, P, Fe, K and Zn, observed were 82.40mg/100g,50.22mg/100g, 106.15mg/100g,3.18mg/100g,119.56mg/100g and 3.92mg/100g respectively, with a minimum concentration of 73.62mg/100g, 36.45mg/100g,81.28mg/100g,1.54mg/100g,83.58mg/100g and 1.70mg/100g respectively. Maximum concentration of vitamins B2,B3,A and C recorded were (0.214,1.15, 8.22 and 4.22)mg/100g respectively with a minimum concentration of (0.170,0.29,4.79 and 3.23)mg/100g respectively. Samples E (75% wheat flour and 25% cocoyam /soy flour) and D (80% wheat flour and 20% cocoyam /soy flour) had te highest protein content of 14.70 and 13.30 respectively. The physical properties of the bread revealed a decrease in loaf volume and specific volume as the proportion of cocoyam / soy flour blend increased and an increase in loaf weight as the proportion increased. The sensory evaluation of the bread samples on a nine- point hedonic scale revealed that sample B (90% wheat flour and 10% cocoyam/soy flour) with a general acceptability of 6.90, compared favorably with bread made from 100% wheat flour.
TABLE OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables viii
List of Figures ix
Abstract x
CHAPTER 1: INTRODUCTION
1.1 Background of Study 1
1.2 Statement of Problem 5
1.3 Justification of the Study 6
1.4 Objectives
of the Study 6
CHAPTER 2: LITERATURE
REVIEW
2.1 History of Bread 7
2.1.2 Types
of bread 8
2.1.3 Chemical composition of bread 9
2.1.4 Nutritional value of bread 10
2.2 Wheat 10
2.2.1 Origin of wheat 10
2.2.2 Physiology of the wheat plant 11
2.2.3 Utilization of wheat 11
2.2.4 Nutritional composition of whole wheat flour 12
2.2.5 Health benefits of whole wheat 13
2.2.6 Importance of wheat in baking products 15
2.2.7 Anti-nutritional factors of whole wheat 16
2.2.8 Functional properties of wheat proteins
(Gluteins and Gliadins) 16
2.3 Soybean (Glycine max) 17
2.3.1 History and origin of soybean 17
2.3.2 Nutritional composition of soybean 18
2.3.3 Anti-nutritional factors in soybean 19
2.3.4 Utilization of soybean 20
2.3.4.1 Oil 22
2.3.4.2 Meal 22
2.3.4.3 Infant formula 22
2.3.4.4 Meat and diary substitutes and extenders 23
2.3.4.5 Other products from soybeans 24
2.3.5 Types
of soy flour 24
2.3.6 Production of soy milk 25
2.4 Cocoyam (XanthosomamaffaScoth) 25
2.4.1 History and origin of cocoyam 25
2.4.2 Anti-nutritional factors in cocoyam 26
2.4.3 Utilization of cocoyam 26
2.4.4 Nutritional value of cocoyam (XanthosomamaffaScoth) 27
2.4.5 Benefits of cocoyam (XanthosomamaffaScoth) 27
CHAPTER
3: MATERIALS AND
METHODS 29
3.1
Sources of Raw Materials 29
3.2
Raw Material Preparation 29
3.2.1 Preparation of soybean flour 29
3.2.2 Preparation of cocoyam flour 29
3.2.3 Preparation of Wheat flour 30
3.4 Preparation of Bread 34
3.5 Blend Formulations 35
3.6 Proximate
Composition 37
3.6.1 Determination of moisture contents 37
3.6.2 Determination of crude protein 37
3.6.3 Determination of crude fat content 38
3.6.4 Determination of ash content 38
3.6.5 Determination of crude fibre content 39
3.6.6 Energy value determination 39
3.6.7 Determination of total carbohydrate 40
3.6.8 Determination of mineral 40
3.6.9 Determination of vitamins 40
3.7 Physical Properties of Bread 40
3.7.1 Loaf volume 40
3.7.2 Weight 41
3.7.3 Specific volume 41
3.8 Sensory Properties of Bread 41
CHAPTER 4: RESULTS
AND DISCUSSION
4.1: Proximate Composition of Wheat, Cocoyam/Soy
Flour Blends 43
4.2: Proximate Composition of Bread Made from
Wheat, Cocoyam/Soy Flour Blends 46
4.3: Mineral Content of Composite Wheat,
Cocoyam/Soy Flour Blends 49
4.4: Mineral Content of Bread Made from Wheat,
Cocoyam/SoyFlour Blends 51
4.5: Vitamin Content of Composite Wheat,
Cocoyam/Soy Flour Blends 53
4.6: Vitamin Content Bread Made from Wheat,
Cocoyam/Soy Flour Blends 55
4.7: Physical Properties of Bread Made from
Wheat, Cocoyam/Soy Flour
Blends 57
4.8: Sensory Evaluation of Bread Made from
Wheat, Cocoyam/Soy Flour Blends 59
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1 Conclusion
61
5.2 Recommendation 61
References 63
Appendices 72
LIST OF TABLES
3.5.1: Sample
formulation 36
4.1:
Proximate composition of wheat,
cocoyam/soy flour blends (%) 45
4.2: Proximate
Composition of bread made from wheat, cocoyam/soy flour blends (%) 47
4.3:
Mineral content of wheat, cocoyam/soy
flour blends (mg/100g) 50
4.4: Minerals
content of bread made from wheat, cocoyam/soy flour blends (Mg/100g) 52
4.5: Vitamins content of wheat, cocoyam/soy
flour blends (mg/100g) 54
4.6:
Vitamins content of wheat, cocoyam/soy
flour blends (mg/100g) 56
4.7: Physical properties of bread made from wheat,
cocoyam/soy flour blends 58
4.8:
Sensory properties of Bread made
from wheat, cocoyam/soy flour blends 60
LIST OF FIGURES
3.1: Flow
diagram for the production of soybean flour 31
3.2: Flow diagram of the
preparation of Cocoyam
(Xanthosomamaffa Scoth) flour 32
3.3: Flow diagram of the
preparation of wheat flour 33
3.4: Flow diagram of the preparation of bread 35
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF STUDY
In
Nigeria and all over the world, bread is an important staple food, with an
exponential increase in consumption over recent years (Bolaniran et al, 2017). Nowadays, bakery food
products, especially bread are becoming very popular in Nigeria in rural as
well as urban areas among all the age groups due to its several attractive
features, including wider consumption, low cost among other processed foods,
varied taste, easy availability and good eating quality (Ayo and Olawale,
2003). The consumption of bread and other bakery products produced from wheat
flour has been a conventional practice (Alam et al; 2013).
Wheat is grown
on more land area than any other food crop, 220.4 million hectares in 2014. World trade in wheat is
greater than for all other crops combined. In 2016, world production of wheat
was 749 million tonnes, making it the second most-produced cereal after maize.
Since 1960, world production of wheat and other grain crops has tripled and is
expected to grow further through the middle of the 21st century. Global demand for wheat is
increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the
production of processed foods, whose consumption is increasing as a result of
the worldwide industrialization process and the westernization of
the diet.(Shewry and Hey, 2015).
Wheat is an
important source of carbohydrates.
Globally, it is the leading source of vegetal protein in human food, having a
protein content of about 13%, which is relatively high compared to other major
cereals, but relatively low in protein quality for supplying essential amino
acids. When eaten as a whole grain, wheat is a source of multiple nutrients and dietary fiber. In a small part of the general
population, gluten – the major part of wheat protein – can trigger coeliac disease, non-coeliac gluten
sensitivity, gluten ataxia
and dermatitis
herpetiformis (Ludvigsson et
al., 2013).
Wheat flour is suitable for bread
production because of its gluten content; a protein which aids excellent
formation of bread dough during fermentation. Wheat flour is also a good source
of calories and other nutrients but its protein is of poor nutritional quality
as its protein is deficient in essential amino acids such as lysine and
threonine (Bakke and Vickers, 2007; Jideani and Onwubali.,
2009). There have been therefore lots of
researches carried out to discover suitable alternatives to wheat flour that
can be used to bake bread thereby reducing the demand for wheat and also
improve the economic value of locally made flour products in Nigeria (Aniedu and Agugo, 2010; Oviahon et al, 2011).
Over the years, the demand for pastry
and baked products in Nigeria has been on the increase. In as much as the
demand for these products increases, the cost of the products also becomes very
expensive (Dotsey, 2009). This high cost is due to the fact that, urbanization
in Nigeria has increased the consumption of processed food and bakery products
as well as increased the demand for imported products. To reduce imports and to
save foreign exchange, it has been proposed that wheat be substituted with
alternative products such as soybeans and cocoyam flour in the production of
bakery products (Dotsey, 2009).
Cocoyam
(Xanthosoma sagittifolium) is
herbaceous perennial plant belonging to the araceae
family and constitutes one of the six most important root and tuber crops
world-wide (Ekanem and Osuji, 2006). They are among the major crops grown in
wetlands with minimal inputs and offer high potential for alleviating food
insecurity and income constraints. Cocoyam is believed to be generally good for
the body and has some medicinal values. Consumption of micronutrient rich food
such as cocoyam is important for a strong immune system that helps the body to
utilize protein, carbohydrates and other nutrients. Cocoyam (Taro) contains
some calcium, vitamin C, vitamin E and B vitamins, as well as magnesium,
manganese, copper and fiber which aids in the digestive process, makes
elimination of stool easy and also helps in cancer prevention (Nwagbo, 2011). Cocoyam
is rich in digestible starch, good quality protein, thiamin, niacin and high
scores of proteins and essential amino acids (Lewu et al, 2009). However, in
spite of its nutritional importance, cocoyam has not received any deliberate
attention to address its research and development. It receives low research
priority in all regional agricultural research centres and therefore, its
contribution to food security and economy is underestimated (Mongi et al, 2011).
Cocoyam
(Xanthosoma maffa (Scoth), is found
in southeast and south-south Nigeria where they grow wild and highly
under-utilized. It is reported to have high content of carotenoids, protein,
fibre, ash but low in carbohydrate (Ukom et
al., 2014), and also contain high antioxidant compounds like flavonoid,
polyphenol and antioxidant activities (Ukom et
al., 2014). The physicochemical and pasting properties show that it has low
retrogradation property, making it a good composite blend for bread production
(Ukom et al., 2015). Although cocoyam
generally contain high level of oxalate which limit their food uses, however,
appropriately processed cocoyam (Xanthosoma
maffa Scoth) can be potential food-based intervention for combating micronutrient
deficiency since it is a source of micronutrients, protein and carotenoids
(which serve as precursors of vitamin A) whose insufficient supply results into
serious physiological abnormalities (Aguaya et
al., 2004; Summer, 2008).
Consumption
of soybean (Glycine max) has in recent years increased, since people are
becoming more health conscious rather than just eating off the shelves and due
to its availability and low cost. Soybean belongs to the family leguminosae and subfamily papillionnideae. It is a rich source of
essential nutrients and contains a wide variety of chemical compounds that have
potent bioavailability. Soybean flour contains about 35 - 45% protein, and is
considered as an excellent source of high quality plant protein with all
essential amino acids required for proper growth and maintenance of body. (Otegbayo
et al., 2018). It is rich in lysine
which is deficient in most cereals. In addition, it is high in vitamins and
minerals, and has been shown to possess natural antioxidant which helps in
lowering cholesterol level, preventing cancer and cardiovascular disease
(Burris et al., 2009), regulation of menopause and combat oxidative degradation
and could also extend the shelf-life of its products (Otegbayo et al, 2018).
Soy beans have recently become popular in the West
African sub region due to their high protein content and quality, and are being
cultivated at a steadily increasing rate. Traditional food uses of soy beans
are very limited, but efforts are being made to promote their incorporation in
the people’s diets. Soy bean has high protein content and is not very expensive
(Kolapo et al., 2005). The high
protein content in the soy supplemented breads would be of nutritional
importance in most developing countries, such as Nigeria, where many people can
hardly afford high proteinous foods because of their expensive costs. Therefore,
the enrichment of bread with other protein and fibre sources such as soybeans,
cocoyam and fibre rich ingredients could enhance the nutritional quality of bread.
1.2 STATEMENT OF PROBLEM
Bread
have remained popular food in Nigeria because of its taste and convenience and
due to its several attractive features, including wider consumption, low cost
among other processed foods, varied taste, easy availability and good eating
quality (Julius and Muyanja, 2019). Despite the increased consumption of bread
in Nigeria, the bread in the Nigerian market are mostly white bread made of
white flour derived from the processing of whole wheat grain in which the bran
and the germ layers have been removed. White bread is high in carbohydrates,
fat, and calorie but low in fiber, vitamins, and minerals which make it
unhealthy for daily use (Serrem et al.,
2011). Wheat contains about 12-16% protein and its protein is of lower
nutritional quality when compared to milk and soya bean proteins as its protein
is deficient in essential amino acids such as lysine and threonine (Julius and
Muyanja, 2019). Therefore, enrichment of bread quality may be achieved by
incorporation of fibre rich ingredients such as coco yam and protein-rich
ingredients from soybean as a fortification of bread.
1.3 JUSTIFICATION OF THE STUDY
To
produce bread from local food sources that can be nutritionally adequate for
all the age groups in order to prevent high rate of protein and micronutrient
deficiency. Also, to reduce wheat importation and improve on the Forex earning
of the nation.
Gluten
free bread is highly needed in the tropical regions especially Nigeria where
bread and other baked products are highly consumed to reduce the costs
implication of wheat importation as well as protecting consumers against celiac
disease. Also it will encourage the exploitation of our indigenous crops for
baked products. In order to obtain good quality gluten-free products from
alternative flours it is necessary to adopt balanced formulations and adequate
technological processes, because of changes in the rheological properties
caused by the lack of gluten. Processing adjustments or new ingredients
(hydrocolloids, protein, and enzymes) are suggested as necessary (Schoenlechner
et al., 2010).
1.4 OBJECTIVES OF THE STUDY
The
main objective of this study is to produce bread from soybean, cocoyam and
wheat flour blends.
The specific objectives
of this study include the following to:
i. produce cocoyam, soybean and wheat
flour.
ii. produce
bread from wheat, soybean and cocoyam flour blends at different proportion.
iii. determine the physicochemical
composition of the produced bread.
iv. determine
the sensory properties of the bread produced.
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