Abstract
This research work on the chemical composition and sensory evaluation of bread made from African yam bean and corn flour blends was done because malnutrition has been the gravest single threat to the world’s public health and is an unbearable burden not only on the health systems, but the entire socio-cultural and economic status of the societies in Nigeria. The objective of this research was to evaluate the chemical composition, functional and sensory properties of the bread made from African yam bean and corn flour blends. The results showed that the substitution of African yam bean and corn flour increases the protein in (g/100g) which ranged from (10.92e ±0.01 to 25.11 a±0.01), fat in (g/100g) (2.29 f±0.01 to 4.03a ±0.01), ash (g/100g) (1.40f ±0.01 to 2.82a ±0.01), fiber in (g/100g) (0.46f ±0.01 to 3.10a ±0.01), Carbohydrate in (g/100g) (50.23f ±0.11 to 66.50a ±0.14), Moisture in (g/100g) (8.29c ±0.17 to 9.41a ±0.22), energy in (kcal) (321.66c ±0.75 to 330.29a ±0.49) and dry matter (80.60c ±0.22 to 81.71a ±0.17). The functional properties which ranged from Bulk density (g/ml) (0.73c ±0.03 to 0.87a ±0.02), water absorption capacity (g/ml) (1.77e ±0.01 to 3.09a ±0.03), oil absorption capacity (g/ml) (0.86e ±0.03 to 2.16a ±0.01), foam capacity (%) (8.42f ±0.01 to 16.71a±0.01), foam stability (g/ml) (1.18f±0.01 to 3.43a±0.03) and gelatinization temperature (oC) (17.39e ±2.14 to 79.53a ±0.03). Vitamin composition of the bread ranged from Pro Vitamin A (ug/g) (3.12f ±0.01 to 32.67a ±0.18), Thiamin (mg/100g) (0.14e ±0.01 to 1.55a ±0.01), Niacin (mg/100g) (0.62d ±0.03 to 1.38a ±0.01) and Vitamin C (mg/100g) (4.76f ±0.01 to 41.76a ±0.02). Mineral content ranged from Calcium (mg/100g) (13.23f ±0.01 to 72.30a ±0.01), Magnesium (mg/100g) (25.76f ±0.01 to 142.57a ±0.01), Potassium (mg/100g) (73.81f ±0.01 to 208.13a ±0.03) and Sodium (mg/100g) (28.38b ±0.01 to 66.15a ±35.37). Antinutrient composition of bread ranged from flavonoid (mg/100g) (0.94f ±0.01 to 11.36a ±0.01), Saponin (mg/100g) (0.02e ±0.01 to 0.41a ±0.01), Tanin (mg/100g) (0.06e ±0.01 to 1.02a ±0.01) and Alkaloid (mg/100g) (0.21d ±0.01 to 1.11a ±0.01) of the African yam bean and corn flour composites flours. However, this incorporation has resulted in a decrease in carbohydrate and increase in moisture content. The study of the functional properties of composite flours showed that the substitution resulted in a significant increase (p <0.05) of the oil absorption capacity, water absorption capacity, bulk density, foam capacity and swelling index while the gelation temperature decreased. Sensory tests indicated that there is a significant difference (p <0.05) between the bread produced from However, it is suggested that African yam bean and corn flour could be suitably incorporated into wheat flour up to a rate of 30%.
TABLE OF CONTENTS
TITLE PAGE i
CERTIFICATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
TABLE OF CONTENTS v
LIST OF TABLES viii
LIST OF FIGURES ix
ABSTRACT x
CHAPTER
1
INTRODUCTION
1.1 Statement of Problem 4
1.2 Objectives of the study 6
1.3 Significance of the study 6
CHAPTER 2
LITERATURE REVIEW
2.1 Corn/Maize 8
2.2 Distribution of Corn 13
2.3 Nutritional value and health benefit of corn 14
2.4 Economic importance of corn 14
2.5 Health Benefits of Corn 15
2.5.1 Healthy Eyes 15
2.5.2 Anemia Prevention 15
2.5.3 Cancer Prevention 15
2.5.4 Source of Fiber 16
2.5.5 Bio Active Plant Compounds 16 2.5.6 Gluten Free 16
2.5.7 Source of Energy 16
2.5.8 Diabetes Management 17
2.5.9 Prevents Hypertension 17
2.6 Fortification of maize products 17
2.7 Economic importance and nutritional
value of African Yam Bean 19
2.8 Effects of processing and
digestibility of African Yam Bean 21
2.9 Baking 23
2.10 Bread making ingredients 23
2.11 Bread making process 23
2.11.1 Mixing and Kneading 24
2.11.2 Rising/Proofing 24
2.11.3 Knocking Back 24
2.11.4 Shaping 25
2.11.5 Second
Proofing or Rise 25
2.11.6 Glazing
(Optional) 25
2.11.7 Baking 25
2.11.8 Cooling 25
CHAPTER 3
MATERIALS AND METHODS
3.1 Experimental design 26
3.2 Sample collection 26
3.2.1 Source of materials 26
3.2.2 Processing of AYB 26
3.2.3 Processing of Corn 26
3.3 Flour
blending 28
3.3.1 Method of bread preparation 29
3.4
Chemical analysis 30
3.4.1 Proximate determination 30
3.5 Vitamin determination 33
3.6
Mineral determination 36
3.7 Antinutrient
determination 37
3.8 Functional properties determination 39
3.9
Sensory evaluation of samples 42
3.10 Statistical analysis 42
CHAPTER
4
RESULTS AND DISCUSSION 43
4.1 Proximate composition of bread made from corn and African yam bean 43
4.2 Functional
properties of bread made from corn and African yam bean 51
4.3: Vitamin
composition of bread made from corn and African yam bean 58
4.4 Mineral
composition of bread made from corn and African yam bean 61
4.5 Antinutrient composition of bread made from corn and
African yam bean 64
4.6 Sensory
attributes of bread made from corn and African yam bean 67
CHAPTER 5
CONCLUSION
5.1 Conclusion 68
5.2 Recommendation 68
REFERENCES 70
LIST
OF TABLES
Table 3.1 Proportion of flour blends 23
Table 3.2 Recipe used for bread making 23
Table 4.1 Proximate composition of bread made from corn
and african yam bean 36
Table 4.2 Functional
properties of bread made from corn and african yam bean 37
Table 4.3 Vitamin
composition of bread made from corn and african yam bean 38
Table 4.4 Mineral composition of bread made from corn
and african yam bean 39
Table 4.5 Antinutrient composition of bread made from
corn and african yam bean 40
Table 4.6: Sensory attributes of bread made from corn
and african yam bean 41
LIST OF FIGURES
Figure 1 Flow chart on the production of African Yam Bean and
Corn Flour 22
CHAPTER 1
INTRODUCTION
Bread can be described as a
fermented confectionary product produced mainly from wheat flour, water, yeast
and salt by a series of processes involving mixing, kneading, proofing, shaping
and baking (Dewettinck et al., 2008).
Bread is an important staple food in both developing and developed countries
and constitutes one of the most important sources of nutrients such as
carbohydrate, protein, fibre, vitamins and minerals in the diets of many people
worldwide (Aider et al., 2012). The
consumption of bread in Nigeria is on a steady increase because it is a
convenient and ready to eat food. According to David (2006) people normally
consume it at breakfast, lunch and sometimes dinner. Oluwajoba et al. (2012) stated that in Nigeria,
bread has become the second most widely consumed non-indigenous food product
after rice. It is consumed extensively in most homes, restaurants, and hotels.
It has been hitherto produced from wheat as major raw material. It is however,
relatively expensive, being made from imported wheat that is not cultivated in
the tropics for climatic reasons (Edema et
al., 2005). Spiekemann (2006) reported that there has been bread from flour
of other cereal grains such as maize, barley, oat; root cassava in combination
with wheat flour. According to Giami et
al. (2004) efforts have been made to promote the use of composite flours in
which flour from locally grown crops and high protein seeds replace wheat flour
for use in baked products, thereby decreasing the demand for imported wheat and
producing nutrient enriched bread.
Maize (Zea mays) is
also referred to as corn, and both words are used as synonyms. Maize ranks as
the second most widely produced cereal crop worldwide. Corn flour contains high
levels of many important vitamins and minerals, including potassium,
phosphorus, zinc, calcium, iron, thiamine, niacin, vitamin B6 and folate
(Watson, 1997). Corn flour nutritionally is superior to others cereals in many
ways, except in protein value (Mejia, 2003). Corn flour is higher in fat, iron
and fiber content. A weak nutritional aspect of maize is the quality of its
protein since around a half of its protein is made up of zein, which is low in
two essential amino acids, lysine and tryptophan. Fortunately this deficiency
now a day has been corrected with the development of the quality protein maize
(QPM), which is nutritionally the most superior cereal grain (Mejia, 2003).
Corn flour is the result of grinding entire corn kernels into a fine powder. It
contains protein, fiber, starch, and the vitamins and
minerals found in whole corn. It’s typically yellow. Maize (Zea mays L.) plays a major role
in nutrition in many countries. Maize is together with rice and wheat, the most
cultivated cereal in the world, regarding the cultivation areas and total
production Wogayehu and Shimelis, (2013). Maize is widely used for human
nutrition as a source of corn flour, starch and oil. Maize is used in several food
products, such us bread, tortillas, snacks, beverages, pancakes, porridges
Gwirtz, and Garcia-Casal, (2014). In the production of bread, it is also used
as wheat flour replacement. Maize is a gluten-free cereal, which is suitable to
produce foods addressed to celiac patients. People with this disease are
intolerant to certain peptides present in gluten, found in the wheat, barley
and rye flours. The only treatment is to follow, throughout life, a gluten-free
diet. Thus con flour, apart from other cereals, pseudo-cereals flours, and
starches, could be used to produce gluten-free products, such as breads.
African yam bean (Sphenostylis
stenocarpa) is one of the lesser known and underutilized legumes that is
very rich in protein, carbohydrate, vitamins and minerals (Wokoma and Aziagba,
2001). According to Potter and Doyle, (2012) African yam bean (Sphenostylis
stenocarpa Hochst ex. A. Rich.) is an underutilized tropical African
tuberous legume. It belongs to the class Magnoliopsida; order Fabales;
family Fabaceae; subfamily Papilionoideaea; and genus Sphenostylis.
There are seven species in the genus Sphenostylis. African yam bean
(AYB) is the most valuable and is one of such species with duo-food products
(grain and tuber). The high protein composition of African yam bean makes it an
important source of protein in the diets of population groups of many tropical
countries. African yam bean tuberous roots have protein content varying from 11
- 19%. The seed have protein content ranged from 21 to 29% and it also contains
some significant amount of carbohydrate and minerals (Nneoma et al,
2012). This legume has been reported to
be of importance in the management of chronic diseases like diabetes,
hypertension, and cardiovascular diseases because of its high dietary fibre
content (Enwere, 2018). It is eaten roasted as groundnut or boiled and blinded
with ingredients like oil, pepper onions and salt and can be to flour for baked
products.
The grains are usually cooked overnight because of the hard
seed coat, owing to the presence of anti-nutritional factors in various
quantities in AYB (like other legumes); Fasoyiro , Ajibode, Omele, Adeniyan and
Farinde (2006). It is a good source of protein, carbohydrate, minerals and
vitamins. AYB is rich in dietary fibre and other phytochemicals that may have
positive effects on health (Ndidi et al., 2014; Ojinnaka et al.,
2017; Onuoha et al., 2017). The primary challenge to wide consumption of
African yam bean (AYB) includes hardness of the seed which results into
longtime cooking and the antinutrient contents of the seed (Aremu and Ibirinde,
2012; Abioye et al., 2015). It is thus very important to find
alternative utilization methods apart from cooking to prevent further neglect
and promote cultivation. The protein of African yam bean is made up of over 32
percent essential amino acids, with lysine and leucine being predominant.
African yam bean seeds can be roasted and eaten with palm kernel as snacks or
boiled and eaten with local seasoning, starchy root crops and fruits (Eneche,
2006). African yam bean seeds can be also processed into flour which can be
used for the production of bakery and confectionary products such as breads,
biscuits, cookies, doughnuts, pie crust and cakes.
1.1 STATEMENT OF PROBLEM
The World Health Organization
cited malnutrition as the gravest single threat to the world’s public health.
Malnutrition is an unbearable burden not only on the health systems, but the
entire socio-cultural and economic status of the society (Aremu et al., 2014). Presently, malnutrition
constitutes a major public health problem especially in the developing
countries. Nigeria is one of the developing countries experiencing malnutrition
crises, as studies on the etiology of malnutrition showed evidence linking
inadequate protein, energy, vitamins and minerals (Uchendu, 2011). Micro
Nutrient deficiency is the world most prevalent and most devastating
nutritional problem, It is a serious childhood problem caused by prolonged
inadequate intake of food rich in micro nutrient example dark green leafy
vegetables, fruits, nuts and fortified foods (Uchendu, 2011). Deficiencies in vitamins iron and iodine
cause’s innumerable maternal and childhood deaths, leaving millions of
survivors blinded or mentally retarded. Even less severe deficiencies impair
intelligence and strength, reducing working capacity and productivity and
impeding economic development.
In Nigeria some cereals and
legumes food are gradually going into extinction because some people see it as
a poor man’s food while others avoid some cereals and legumes food due to
ignorant of its nutritional and economic importance. Most foods crops are lost
to post harvest loses due to poor storage facilities and processing technology.
Wheat is the basic raw material in bread making, which is imported into Nigeria
involving huge expenditure of foreign exchange, leading to high cost of bread
in order to make bread affordable by low income earners who constitute the
larger population of consumers.
Therefore, this study aim to
produce bread from maize and African yam bean which is high in the essential
mineral and vitamin to curb the deficiencies in nutrition.
1.2 OBJECTIVES
OF THE STUDY
The general
objective of this study is to produce and evaluate bread produced from blends
of maize and African yam bean flour.
The specific
objectives include:
1.
To evaluate the chemical composition of the bread made from
African yam bean and corn flour blends.
2.
To evaluate the sensory properties and the acceptability of
bread produced from African yam bean and corn flour blends.
3.
To determine the functional properties.
4.
To determine the proximate composition
1.3 SIGNIFICANCE OF THE STUDY
In Nigeria, there is need to
promote the utilization and production of low cost indigenous foods. The
incentives for developing low cost food include changing consumer’s state and
prevailing health benefits. The success of this work may help to alleviate the
teaming nutrient deficiencies through the many nutrient made readily available
in this new product. The research work will help the general public understand
that African yam bean and corn flour is a very good source of protein, fats and
many micro nutrients which when made into flour can be readily added to food to
enrich the food nutrients. Findings will also inspire the baking industries
into producing nutrient dense food products rich in nutrients important for
normal body activities. The result of this paper will enhance the population on
the nutrient content of the underutilized African yam bean and corn flour its
application in the supplementation of food.
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