ABSTRACT
This study was aimed at improving the usage of the highly underutilized watermelon seeds in the production of bread. The evaluation and chemical composition of corn bread produced from a combination of corn and watermelon seed was done using various proportions of watermelon seed flour and corn flour, 70% -30%, watermelon seed flour and corn flour, 50%-50%, watermelon seed flour and corn flour,70%-30% corn flour and watermelon seed flour, 100% corn four was used as control. The proximate, mineral and vitamin contents of the baked bread samples were carried out in duplicates. The results indicated that the protein content of the baked products increased increased with increase in the proportion of the watermelon seed flour, while the carbohydrate content increased with increase in the proportion of the corn flour. However, the product containing 50% corn flour and 50% watermelon seed flour scored significantly higher 12.61
0.13 (p< 0.05) than the other smpoles. The product with 70% watermelon seed flour and 30% corn flour scored higher 7.0
1.44 and 97.2
1.70 (p<0.05) in taste and general acceptability respectively. While the product with 100% corn flour scored significantly higher 7.7
0.09 and 6.8
1.56 (p<0.05) in terms of appearance and texture respectively. Thus, the high concentration of protein makes watermelon seeds suitable for supplementation of foods and therefore recommended for utilization in bakery and confectioneries and increased consumption by individuals as it is a good source of protein.
TABLE OF CONTENTS
Title page i
Certification ii
Dedication iii
Acknowledgements iv
Table of Contents v
List of Tables vii
List of Figures viii
Abstract ix
CHAPTER 1
INTRODUCTION 1
1.1 Statement of problem 3
1.2 Objectives of the study 4
1.3 Significance of the study 5
CHAPTER 2
LITERATURE REVIEW 6
2.1 Origin and geographical distribution of watermelon (Citrullus lanatus) 6
2.2 Nutritional value and food use 7
2.2.1 Proximate composition of watermelon 7
2.2.2 Mineral content of raw watermelon (Citrullus Lanatus) 8
2.2.3 Vitamin content of raw watermelon 8
2.3 Watermelon seed kernels 9
2.4 Origin of Corn (Maize) 12
2.5 Nutritional Value of Corn 13
CHAPTER 3
MATERIALS AND METHOD 17
3.1 Sample collection 17
3.2 Sample preparation 17
3.2.1 Preparation of the watermelon seed flour 17
3.2.2 Preparation of flour blends 18
3.3 Preparation of baked sample 18
3.3.1 Bread production 18
3.3.1.1 Sample recipe 18
3.3.2 Method 19
3.4 Chemical analysis 19
3.4.1Proximate 19
3.4.1.1 Moisture 19
3.4.1.2 Ash 20
3.4.1.3 Crude fibre 20
3.4.1.4 Fat 21
3.4.1.5 Protein 21
3.4.1.6 Carbohydrate 22
3.5 Mineral determination 22
3.5.1 Calcium and Magnesium determination 23
3.5.2 Phosphorus determination 24
3.5.3 Determination of sodium and potassium 24
3.6 Vitamins determination 25
3.6.1 Vitamin C (Ascorbic acid) 25
3.6.2 Determination of riboflavin 26
3.6.3 Determination of thiamin 27
3.7 Sensory evaluation 27
3.8 Statistical analysis 28
CHAPTER 4
RESULT AND DISCUSSION 29
4.1Production of Bread from Corn and Watermelon seed flour 29
4.2 Proximate composition of breads 30
4.3Mineral composition of breads 32
4.4 Vitamin composition of breads 34
4.5 Sensory properties of breads 35
CHAPTER 5
CONCLUSION AND RECOMMENDATION 38
5.1 Conclusion 38
5.2 Recommendation 38
REFERENCE
Appendix I
Appendix II
LIST OF TABLES
Table 2.1 Proximate composition of raw watermelon (Citrullus lanatus) 7
Table 2.2 Mineral content of raw watermelon 8
Table 2.3 vitamin content of raw watermelon 9
Tale 2.4 Proximate composition of watermelon seed kernels, dried 10
Table 2.5 Mineral content of watermelon seed kernels, dried 11
Table 2.6 Vitamin content of watermelon seed kernels, dried 11
Table 2.7 Lipid composition of watermelon seed kernels, dried 12
Table 2.8 Proximate composition of corn, whole white raw 13
Table 2.9 Micronutrient composition of Corn, whole white, raw 14
Table 2.10 Lipid content of corn, whole white, raw 15
Table 2.11 Nutrient Composition of Bread Produced From Various 16
Table 3.1 Sample proportion of flour blends 18
Table 4.1 Proximate composition of bread samples 30
Table 4.2 Mineral content of bread samples 34
Table 4.3 Vitamin content of bread samples 35
Table 4.4 Sensory of bread sample 37
LIST OF FIGURES
Figure 1: Flow diagram from the processing of dried watermelon
seed to flour 17
Figure 2: Bread produced from a combination of corn and
watermelon seed flour 29
CHAPTER 1
INTRODUCTION
The edible fruit of watermelon (Citrullus lanatus) belongs to the family cucurbitaceae. The fruit contains many obovate, smooth compressed seeds thickened at the margin and of black or yellowish white color (Sodeke, 2005).
Watermelon is one of the major underutilized fruits grown in the warmer part of the world Although the juice or pulp from watermelon (Citrullus lanatus) is used for human consumption, the rind and seeds are major solid wastes (Dane and Liu, 2007). Water melon seeds are potential source of protein and Lipids (Zohary and Hopf, 2000; Mandel, 2005 and Motes et al., 2005).Flour of watermelon seed contain several anti-oxidant fibers such as starchyose, raffinose and verbascose (Parsons, 2000; Mossler, 2007).
Watermelon seed oil, rich in linoliec acid (64.5%), is used for frying and cooking in some African and middle Eastern American countries owing to its unique flavor (Akoh and Nwosu, 1992). The watermelon, (Citrullus colocynths lanatus) family cucurbitaceae is the Tmost popular fruit in Serbia, with a traditional name “Lubanica”, (Milovanovic and Jovanovich, 2005). Watermelon seeds are very high in protein; it consists of nine essential and non- essential amino acids, including , Tryptophan 421mg, Threonine 1201mg, Isoleucine 1449mg, Leucine 2321mg, Lysine 958mg, Methionine 901mg, Cystine 473mg, Phenylalanine 2193mg, Tyrosine 1097mg, Valine 1680mg, Arginine 5289mg, Histidine 837mg, Alanine 1611mg, Aspartic acid 2985mg, Glutamic acid 6155mg, Glycine 1796mg, Proline 1351mg, Serine 1628mg.
The seeds are low in carbohydrate, but high in calories, so roasted watermelon seeds can be a good choice for supporting athletes’ activities. Water melon seeds are also loaded with several of the B vitamins like thiamin, riboflavin, niacin, vitamin B6 and pantothenic acid, which are necessary for converting food into energy and other important bodily functions. The most prevalent B vitamin in watermelon is niacin. Niacin is important for maintaining the nervous system, digestive system and promotes skin health. Magnesium is the most abundant mineral. It helps regulate blood pressure. Other important minerals in watermelon seeds are phosphorus, iron, potassium, sodium, copper, manganese and zinc. Iron is a vital nutrient the body needs for proper oxygen delivery throughout the body and cell growth. It also contains saturated fats, monounsaturated fats, polyunsaturated fats, and omega-6-fatty acids which can help in the reduction of high blood pressure. Polyunsaturated fats may improve cholesterol levels and reduce risk of both heart disease and type 2 diabetes. Watermelon seeds are effective in recovering health after illness and sharpening memory
(Vanwyk and Gericke, 2000; Ma t t s o n and Grundy, 1985).
Cereals are plant foods which are derived from seeds of the grass family (Onimawo and Egbekun, 1998). Cereals are fruits of cultivated grasses belonging to the monocotyledonous family gramineae. The principal cereal crops of the world include wheat, barley, oat, rye rice, maize (Corn), sorghum, and millet but the chief cereals of the developing tropical countries of West Africa are maize (Corn), rice, sorghum and millet (Okaka, 1997). Corn is a major cereal crop worldwide (Mellor et al., 1987; Blackie, 1990; Byerlee and Eicher, 1997; Gibson and Benson, 2007). Maize (zea mays) or corn is a cereal crop that is grown widely throughout the world in a range of maize plant agro ecological environments. More maize is produced annually than any other grains. About 50 species of maize exists and consist of different colors, textures and grain shapes and size. White and red are the most common types. The white and yellow varieties are preferred by most people depending on the region (IITA, 2009).
Maize was introduced into Africa in the 1500’s and has since become one of Africans dominant food crops (IITA, 2009). Like many other regions, it is consumed as a vegetable although it is a grain crop. The grains are rich in vitamin A (yellow), C and E carbohydrates, and essential minerals and contain 9% protein. They are also rich in dietary fiber and calories, which are a good source of energy (IITA, 2009). Corn is composed of 76%, 86 calories, 3% protein 1% fat, 3% Fiber and 19% carbohydrates in 100g (USDA, 2014). Cereal grains are used in various forms. They can be consumed as they are for food or slightly modified form. They can be further processed into flour, starch, oil, bran, sugar syrup; Cereal grains are also fed to livestock which convert them to animal protein of meat, milk, and eggs (Onimawo and Egbekun, 1998). The high protein content of water melon seeds with a fairly high concentration of the amino acids makes the seeds suitable for supplementation with other foods (Taiwo et al., 2008).
1.1 STATEMENT OF PROBLEM
Protein energy malnutrition (PEM) remains a major public health issue in the developing countries of the world of which Nigeria is a part and it appears to be recalcitrant due to the high level of poverty, overcrowding and HIV/AIDS in the developing countries. In fact poverty is the underlying factor of majority of PEM in the developing countries. Statistical data from the World Bank shows that as at 2010 68% of Nigerians live on <1.25 dollars per day (World Bank Report, 2011). The trend of people living below the poverty line was similar in pattern with the trend of the severe malnourished (< -3SD) among preschool children (Central Bureau of Statistics, 2000).
It is estimated that about 182 million or 1 in 3 children under the age of five years in developing countries mostly in sub-Saharan Africa are malnourished. Furthermore, approximately, 6.6 million of the 12.2 million under five deaths occurring annually in third world countries are attributable to malnutrition(Ulasi and Ebenebe, 2007).PEM is associated with as much as 50-60% of under-five mortality in poor countries and a myriad of morbidities.This study aims to improve the usage of the highly underutilized watermelon seeds in the production of bread in combination with corn flour as the supplementation of corn flour which is limited in protein with watermelon seed flour which has a high concentration of amino acids will have a good implication in a society with high protein deficiency.
1.2 OBJECTIVES OF THE STUDY
1.2.1 General Objective:
The general objective of this study is to evaluate the sensory properties and chemical analysis of bread produced from a combination of corn and watermelon seed flour.
1.2.2 Specific objectives:
The specific objectives include:
1. To produce bread from a combination of corn and watermelon seed flour
2. To evaluate the sensory properties of bread produced from a combination of corn and watermelon seeds flour
3. To determine the chemical (proximate, vitamin and mineral) composition of bread produced from a combination of corn and watermelon seed flour.
4. To determine the proportion more acceptable in terms of nutrient and sensory properties
1.3 SIGNIFICANCE OF THE STUDY
The result of this study would help the general public understand that watermelon seeds are very good source of protein which when made into flour can be readily added to foods to increase the protein content and would go a long way to reduce the occurrence of Kwashiorkor (PEM or Protein energy malnutrition). Findings will also:
1. Inspire the bakery industries into producing nutrient dense baked products rich in nutrient important for normal functioning of the body (eg carbohydrates, fats, proteins and essential micronutrients)
2. Enhance the awareness of the entire community (population) on the nutrient content of the underutilized watermelon seed and its application in the supplementation of foods.
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