A dive into experimental research. This study aims to advocate for the increased utilization of the nutrient dense watermelon seeds in the production of our every day snacks.

1. 1
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.

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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

3. 3
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

4. 4
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

5. 5
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.

6. 6
CHAPTER 2
LITERATURE REVIEW
2.1 ORIGIN AND GEOGRAPHICAL DISTRIBUTION OF WATERMELON
(Citrullus Lanatus).
Watermelon is thought to have originated in Southern Africa because it is found growing
wild throughout the area, and reaches maximum diversity of forms there (Wehner, 2010).
It has been cultivated in Africa for over 4, 000 years (Wehner, 2010). In 1857, David
Livingstone reported watermelon growing profusely in the Kalahari Desert (Namibia and
Botswana), after unusually heavy rainfall (Wehner, 2010). The natives there knew of sweet
as well as bitter forms of watermelon growing throughout Southern Africa (Wehner, 2010).
De Candolle, in 1882, considered the evidence sufficient to prove that watermelon was
indigenous to tropical Africa, more specifically he Southern parts of Africa (Wehner,
2010). Citrullus colocynth is considered the wild ancestor of watermelon (Citrullus
Lanatus), and is now found native in North and West Africa (Wehner, 2010). Although
Citrullus species grow wild in Southern and central Africa, C. Colocynths also grows wild
in India. India and China may be considered secondary centers’ of diversity for the genus
(Wehner, 2010). Cultivation of watermelon began in ancient Egypt and India, and is
thought to have spread from those countries through the Mediterranean, Near East, and
Asia and the crop has been grown in the United states since 1629 (Wehner, 2010).

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2.2 NUTRITIONAL VALUE AND FOOD USE
A watermelon contains about 6% sugar and 91% water. It is a good source of vitamin C
(ascorbic acid). The amino–acid citrulline is produced in watermelon rind (Rimando and
Perkins–veazie, 2005). Watermelon pulps contain carotenoids, including lycopene
(Perkins- Veazie et al., 2006). Water melon rinds are also edible. They are used for making
pickles as well for extraction of pectin and are sometimes used as a vegetable (Zohary and
Hopf, 2000 and Mandel, 2005; Wehner, 2008). The seeds have a nutty flavor and can be
dried and roasted, or ground into flour and are potential source of protein and lipids
(Zohary and Hopf, 2000; Mandel, 2005; Motes et al., 2005). Watermelon pulp or juice can
be made into wine, on its own or blended with other fruits (Keller, 2002).
2.2.1 Proximate composition of watermelon
Table 2.1 summarizes the proximate composition of raw watermelon pulp. Watermelon is
composed of 91% moisture, 30 calories, 0.6% protein, 0.1% fat, 8% carbohydrate and 0.4%
total dietary fiber per 100g.
Table 2.1: Proximate composition of raw watermelon (Citrullus lanatus).
Nutrient Value per 100g
Water 91.45g
Protein 0.61g
Lipid 0.15g
Carbohydrate 7.55g
Fiber 0.4g
Sugars 6.20g
Source: USDA National Nutrient Database for Standard Reference (2014)

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2.2.2 Mineral content of raw watermelon (Citrullus Lanatus)
Mineral composition of watermelon is presented in the table below. Watermelons are low
in calcium supplying 7mg in 100g, but are fairly good source of potassium providing
112mg per 100g. Watermelon also provides 0.24mg, 10mg, 11mg, 1mg and 0.10 mg of
iron, magnesium, phosphorus, sodium and zinc respectively.
Table 2.2: Mineral content of raw watermelon
Nutrient Value per 100g
Calcium, ca 7mg
Iron, Fe 0.24mg
Magnesium, mg 10mg
Phosphorus ,P 11mg
Potassium, K 112mg
Sodium, Na 1mg
Zinc, Zn 0.10mg
Source: USDA National Nutrient Database for standard Reference (2014).
2.2.3 Vitamin content of raw watermelon
Table 2.3 below summarizes the vitamin composition of watermelon. Watermelon contains
8.1mg of vitamin C, 0.18mg of niacin, 0.03mg of thiamin and 0.02mg riboflavin.

9. 9
Table 2.3: vitamin content of raw watermelon
Nutrient Value per 100g
Vitamin .C 8.1mg
Thiamin 0.03mg
Riboflavin 0.02mg
Niacin 0.18mg
Vitamin B.6 0.05mg
Folate, 3µg
Vitamin A, 28µg
Vitamin A, 569IU
Source: USDA National Nutrient Database for standard Reference (2014)
2.3 WATERMELON SEED KERNELS
The fruit of watermelon contains many obovate, smooth compressed seeds thickened at the
margin and of black or yellowish white color (Sodeke, 2005). Watermelon seeds are
potential source of protein and lipids (Zohary and Hopf, 2000; Mandel, 2005; Motes et al.,
2005). The flour of watermelon seed contains several anti-oxidants fibers e.g. starchyose,
raffinose and verbascose (Parsons, 2000; Mossler, 2007). Watermelon seed is another
ready source of oil like the peanut and soybean seeds. The fairly high concentration of
amino acids makes the seed suitable for fortification of foods (Taiwo et al., 2008) Nutritive
value of watermelon seeds (100g);
 Energy 628kcal,
 Protein 34.1g,
 Fats 54.6g,
 Carbohydrate 4.5g,
 Calcium 100mg,
 Phosphorus 937mg,
 Iron 7.4mg,

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 Minerals 3.7g,
 Moisture 4.3g,
 Crude fiber 0.8g, (Gopalan et al, 2007).
Table 2.4, below summarizes the proximate composition of dried watermelon seed kernels,
watermelon seeds are very low in carbohydrate providing 15.31g per 100g but high in
calories (55.7g), lipid (47.37g), and protein (28.33g).
Tale 2.4: Proximate composition of watermelon seed kernels, dried.
Nutrient Value per 100g
Water 5.05g
Energy 55.7kcal
Protein 28.33g
Total Lipid (Fat) 47.37g
Carbohydrate, by difference 15.31g
Source: USDA National Nutrient Database for Standard Reference (2014)
Table 2.5 below summarizes the mineral content of watermelon seed kernels per 100g
dried. Watermelon seed kernels are very rich in phosphorus, potassium and magnesium,
providing 755mg, 648mg and 515mg respectively. This indicates its micronutrient density.

11. 11
Table 2.5: Mineral content of watermelon seed kernels, dried.
Nutrient Value per 100g
Calcium 54mg
Iron 7.28mg
Magnesium 515mg
Phosphorus 755mg
Potassium 648mg
Sodium 99mg
Zinc 10.24mg
Source: USDA National Nutrient Database for Standard Reference (2014).
Table 2.6 below summarizes the vitamin content of watermelon seed kernels, dried.
Watermelon seed kernels are rich in niacin, 3.55mg, and 58mg folate, it also contains
thiamin 0.19mg, riboflavin 0.15mg.
Table 2.6: Vitamin content of watermelon seed kernels, dried.
Nutrient Value per 100g
Vitamin C 0mg
Thiamin 0.19mg
Riboflavin 0.15mg
Niacin 3.55mg
Vitamin B.6 0.09mg
Folate, 58µg
Vitamin A, 0IU
Source: USDA National Nutrient Database for standard Reference (2014).

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Table 2.7 summarizes the lipid composition of watermelon seed kernels.
Watermelon seed kernels contains no cholesterol, however it is a rich source of
polyunsaturated fatty acids containing 28.09g, 9.78g of saturated fatty acid and 7.41g of
monounsaturated fatty acids.
Table 2.7 Lipid Composition of watermelon seed Kernels, dried.
Nutrient Value per 100g
Fatty acids, total saturated 9.78g
Fatty acids, total monounsaturated 7.41g
Fatty acids, total polyunsaturated 28.09g
Cholesterol 0mg
Source: USDA National Nutrient Database for standard Reference (2014)
2.4 Origin of Corn (Maize)
Although corn is indigenous to the Western hemisphere, its exact birth place is far less
certain (Gibson and Benson, 2002). For Western civilization the story of Corn began in
1492 when Columbus’s men discovered this new gain in Cuba, an American native, it was
exported to Europe rather than being imported, as were other major grains. It is known by
other names around the world. Corn is often classified as dent corn, flint corn, flour corn,
popcorn, sweet corn, waxy corn and pod corn. Corn was the most important cultivated
plant in Ancient times in America (Mellor et al., 1987; Blackie, 1990; Byerlee and Eicher,
1997; Gibson and Benson, 2002).

13. 13
Early North American expeditions show that the corn-growing areas are extended from
Southern North Dakota and both sides of the lower St. Lawrence valley Southern to
Northern Argentina and Chile, It extended Westward to the middle of Kansas and
Nebraska, and an important lobe of the Mexican area, extending Northward to Arizona,
New Mexico and Southern Colorado. It was also an important crop in the high valleys of
the Andes in South America (Gibson and Benson, 2002).
2.5 Nutritional Value of Corn
In a 100g serving, Corn (Maize Kernels) provides 86 kcal and is good source of the B-
vitamins, thiamin, niacin and folate.
Table 2.8, below summarizes the proximate content. Corn contains low carbohydrate
19.02g, and is also low in protein 3.22g and lipid.
Table 2.8 Proximate composition of corn, whole white raw
Nutrient Value per 100g
Water 75.96g
Energy 86kcal
Protein 3.22g
Total Lipid (Fat) 1.18g
Carbohydrate, by difference 19.02g
Fiber, total Dietary 2.7g
Sugars, total 3.22g
Source: USDA National Nutrient Database for standard Reference (2014)

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Table 2.9 shows the micronutrient composition of Corn. Corn is rich in potassium 270mg,
folate 46mg, and also contains 6.8mg of vitamin C, 1.70mg niacin and 0.20mg 0f thiamin.
Table 2.9: Micronutrient composition of Corn, whole white, raw
Nutrient Value per 100g
Calcium 2 mg
Iron 0.52mg
Magnesium 37mg
Phosphorus 89mg
Potassium 270mg
Sodium 15mg
Zinc 0.45mg
Vitamin .C, total 6.8mg
Thiamin 0.20mg
Riboflavin 0.06mg
Niacin 1.70mg
Vitamin B-6 0.06mg
Folate, 46µg
Vitamin A, 1IU
Source: USDA National Nutrient Database for standard preference (2014)

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Table 2.10 shows the lipid content of Corn. Corn has no cholesterol; however it contains
0.18g of saturated fatty acid, 0.35g of mono unsaturated fatty acids and 0.56g.
Table 2.10: Lipid content of corn, whole white, raw.
Nutrient Value per 100g
Fatty acids, total saturated 0.18g
Fatty acids total mono unsaturated` 0.35g
Fatty acids, total poly unsaturated 0.56g
Cholesterol 0`mg
Source: USDA National Nutrient Database for standard Reference (2014)
Table 2.11 summarizes the nutrient composition of various cereals. The moisture contents
ranges from 7.80g-37.30g, with rye bread having the most moisture content, while wheat
bread protein scoring the highest, with the energy value of Corn bread having the highest
energy.

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Table 2.11: Nutrient Composition of Bread Produced From Various
WHEAT BREAD RYE BREAD CORN BREAD
Water 35.20g 37.30g 7.80g
Energy 267kcal 259kcal 418kcal
Protein 10.72g 8.50g 7.00g
Lipids 3.24g 3.30g 12.20g
Carbohydrate 48.68g 48.30g 69.50g
Dietaryfiber 4.0g 5.8g 6.5g
Calcium 133mg 73mg 57mg
Magnesium 45mg 40mg 24mg
Phosphorus 149mg 125mg 489mg
Potassium 177mg 166mg 113mg
vitaminC 0.2mg 0.4mg 0.1mg
Thiamin 0.42mg 0.43mg 0.05mg
Riboflavin 0.25mg 0.34mg 0.02mg
Niacin 5.62mg 3.81mg 0.94mg
Source:USDA National NutrientDatabase forStandardPreference (2014).

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CHAPTER 3
MATERIALS AND METHOD
3.1 Sample collection
The Watermelon fruits (Citrullus lanatus) and corn flour (zea mays) was purchased from
Ubani main market in Umuahia, Abia State.
3.2 Sample preparation
3.2.1 Preparation of the watermelon seed flour
The watermelon fruit was washed and properly cleaned, the fruits were cut open and the
seeds collected. The seeds were washed and sundried for 7 days, this is because Oil from
the sun-dried sample will however, be preferable because of its low acid value (before it
was milled and sieved. The following flow chart describes the steps.
Watermelon seeds
Washed
Dried
Milled
Sieved
Watermelon seed flour
Figure 1: flow diagram from the processing of dried watermelon seed to flour

18. 18
3.2.2 Preparation of flour blends
Table 3.1 shows the proportions of the flour blends or composites used for the production
of the baked samples.
Table 3.1: Sample proportion of flour blends
Sample 401 Sample 402 Sample 403 Sample 404
70% - 30% 50% - 50% 70% - 30% 100%
Watermelonseed
flour – corn flour
Watermelonseed
flour – corn flour
Cornflour–
Watermelonseed
flour
Corn flour
3.3 Preparation of baked sample
3.3 Bread production
The bread samples were produced with various proportions of the composites flours,
adapting and adjusting the yeast bread method described by largen (1984)
3.3.1 Sample recipe
Flour 100g
Margarine 30g
Sugar 25g
Yeast 3g
Water 1/8cup
Salt 1g
Milk 1tsp

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3.3.2 Method
All the ingredients were combined and beaten until smooth to make moderately stiff dough.
On a lightly floured pastry board, the dough were kneaded until smooth and elastic and
then placed in lightly greased bowl; i turned the dough once to grease top and allowed to
rise in a warm place until double in bulk then tested for lightness with two fingers. When
dough was light, it was punched down and divided into half, shaped into rolls and then
baked at 2200c (4250f) for 15 minutes.
3.4 Chemical analysis
The proximate, mineral and vitamin contents of the baked samples (bread) were carried
out in duplicates.
3.4.1 Proximate
3.4.1.1 Moisture
The moisture content was determined using the method of Association of Official
Analytical Chemist (AOAC, 2005). About 5g of sample was weighed into petri dish of
known weight. It was then dried in the oven at 105 ± 1ºC for 4 hours. The samples were
cooled in a desiccators and weighed. The moisture was calculated as follow:
Percentage moisture = change in weight X 100
Initial weight of sample before drying 1

20. 20
3.4.1.2 Ash
Ash content was determined using the method of (AOAC, 2005). About 5g of each sample
was weighed into crucibles in duplicate, and then the sample was incinerated in a muffle
furnace at 550˚C until a light grey ash was observed and a constant weight obtained. The
sample was cooled in the desiccators to avoid absorption of moisture and weighed to obtain
ash content. Percentage ash was calculated from the formula;
% Ash= W2 – W1 X 100
W 1
Where W1 = Weight of empty crucible
W2 = Weight of crucible + food before drying
W3 = Weight of crucible + ash
W = Dry weight of food sample
3.4.1.3 Crude fiber
Crude fiber was determined using the method of (AOAC, 2005). About 5g of each sample
was weighed into a 500 ml Erlenmeyer flask and 100 ml of TCA digestion reagent was
added. It was then brought to boiling and refluxed for exactly 40 minutes counting from the
start of boiling. The flask was removed from the heater, cooled a little then filtered through a
15.0 cm no. 4 Whitman paper. The residue was washed with hot water stirred once with a
spatula and transferred to a porcelain dish. The sample was dried overnight at 105ºC .after
drying; it was transferred to a desiccator and weighed as W1. It was then burnt in a muffle
furnace at 500ºC for 6 hours, allowed to cool, and reweighed as W2. The crude fiber was
calculated thus
% crude fiber = W1 – W2 X 100
W 1

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Where W1 = weight of crucible + dried sample,
W2 = weight of crucible + ash,
W = Dry weight of food sample.
3.4.1.4 Fat
Fat content was determined using the method of (AOAC, 2005). About 10g of sample
wrapped in filter paper was weighed using a chemical balance. It was then placed in an
extraction thimble that was previously cleaned, dried in an oven, and cooled in the
desiccators before weighing. Then, about 25 ml of petroleum ether solvent was measured
into the flask and the fat content was extracted. After extraction, the solvent was
evaporated by drying in the oven. The flask and its contents were cooled in a desiccator
and weighed. The percentage fat content was calculated as follows:
%fat content = weight of the fat extracted X 100
Weight of the sample 1
3.4.1.5 Protein
The protein content was determined using a micro-Kjedahl method (AOAC, 2005) which
involves wet digestion, distillation, and titration. The protein content was determined by
weighing 3g of sample into a boiling tube that contained 25 ml concentrated sulfuric acid
and one catalyst tablet containing 5g K2 SO4, 0.15g CUSO4 and 0.15g TiO2.Tubes were
heated at low temperature for digestion to occur. The digest was diluted with 100ml
distilled water, 10 ml of 40% NaOH, and 5 ml of boric acid. The NH4 content in the

22. 22
distillate was determined by titrating with 0.1N standard HCL using a 25 ml burette. A
blank was prepared without the sample. The protein value obtained was multiplied by a
conversion factor, and the result was expressed as the amount of crude protein.
% crude protein = actual titer value – titer of the blank X 0.1N HCL X 0.014 X conversion
factor X 100 / weight of the sample.
3.4.1.6 Carbohydrate
The carbohydrate content was calculated by difference as the nitrogen free extractive (NFE), a
method separately described by James (2005). The Nitrogen free Extractive was calculated as
% NFE= 100 - % (a+b+c+d+e)
Where a = protein
b = fat
c = fiber
d = ash
e = moisture
3.5 Mineral determination
The mineral contents of the baked samples were done following the dry ash extraction
method described by Onwuka (2005). A measured weight of the sample was burnt to ashes (as
in ash determination) thereby removing all the organic materials leaving the inorganic ash. The
resulting ash was dissolved in 5 ml of dilute 2M. HCL solution and then dilute to 100 ml in a
volumetric flask. This extracts was used in specific analysis for the different mineral elements.

23. 23
3.5.1 Calcium and Magnesiumdetermination
Calcium and magnesium was determined by complexiometric titration. The versante EDTA
titrimetric method of AOAC (2005) was employed .20 ml portion was dispersed into conical
flask and treated with pinches of the masking agents (hydroxylamine hydrochloride, sodium
cyanide and sodium potassium ferrocyanide). The mask was added to it to raise the pH to 10.00
(a point at which both calcium and magnesium form complexes with EDTA). The mixture was
titrated against 0.02N EDTA solution using Ferrochrome dark T as indicator. A reagent blank
was titrated and titration in each case was done from deep red to a permanent blue end point.
The titration value represents both Ca2+ and Mg2+ in the test sample. A reagent titration was
done to determine Ca2+ alone in test samples. Titration of calcium alone was done in similarity
with the above titration. However, 10% NaOH was used in place of the ammonia buffer and
solo chrome dark blue indicator in place of Ferrochrome Black T. from the titer values
obtained, the Ca2+ and Mg2+ content were calculated as shown below:
%Ca/Mg = 100 X T –B(NxCa/Mg)x Vt
W va
Where
T = titer value of sample
Vt= total extract volume
Va= volume of extract analyzer
W = weight of the sample
B = titer value of blank
Ca = calcium equivalence
Mg = magnesium equivalence
N = Normality of titrate
(0.02EDTA)

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3.5.2 Phosphorus determination
The phosphorus in the sample was determined by molybdate vanadate calorimetric method.
A measured volume of the volume of the dry ash (2mg) digest of the sample was dispersed
into a 50 ml volume flask. At the same time, the same volume of distilled water and
standard P solution were measured into different flask to serve as reagent blank and
standard respectively. 2 ml of the phosphorus color reagent (molybdo vanadate solution)
was added to each of the flask and allowed to stand at room temperature for 15 minutes.
The content of each flask was diluted to the 50 ml mark with distilled water and its
absorbance was measured in a spectrophotometer at a wavelength of 540m with the reagent
blank at zero. The phosphorus content was calculated using the formula below:
P mg/100g =100 X au X c X vt
W as va
Where: w = weight of sample
Au= absorbance of test sample
As= absorbance of standard phosphorus solution
C = concentration of standard phosphorus solution
Vt= total extract volume
Va= volume of extract analyzer
3.5.3 Determinationof sodiumand potassium
Sodium and potassium was determined by flame photometry. The instrument, Jaway digital
flame photometer was set out according to the manufacturer instruction. It was switched on
and allowed about 10 to 15 minutes to equilibrate. Meanwhile standard sodium and
potassium solution were prepared separately and diluted in series to contain 10, 8, 6, 4 and
2 pp of Na and K respectively.

25. 25
After calibrating the instrument, 1ml of each standard was aspirated into it and sprayed over
the non luminous flame. The optical density of the resulting emission from each standard
solution was recorded. Before flaming, the appropriate element filter (Na or K) was put in
place with the standard measured, the test sample extract measure in time and they were
plotted into standard cause which was used to extrapolate the content of each test element
and calculated as shown below:
Na or K (mg/100g) = x X vt X D X 100
1000 va w
Where x is the concentration of the test element from the curve.
3.6 Vitamins determination
The vitamins would be determined according to the methods described by
Onwuka (2005).
3.6.1 Vitamin C (Ascorbic acid)
Five grammes (5g) of the sample were dispersed in 50ml of EDTA/TCA Solution
and homogenized. The homogenate was filtered with Whitman No 42 filter paper and
more of the extracting solution was used to wash the residue in the filter paper until 50ml
filtrate was obtained. A 20ml portion of the filtrate was measured into a conical flask and
10ml of 30% of KI solution was added to it mixed well and then followed by 1% starch
solutions. The mixture was titrated against 0.01m of CuSO4 solution. A reagent blank was
titrated. Vitamin C content was calculated based on the relationship that 1ml 0.01m
CuSO4 =0.88mg vitamin C

26. 26
Therefore vitamin C mg/100g = 100 X 0.88 X (t-b) X vt
W va
Where w – weight of sample
T – Titer value of sample
B - Titer value of blank
Vt – total extract volume
Va – volume of extract titer
3.6.2 Determination of riboflavin
5mg of sample would be weighed into a conical flask and 50ml of 0.2NHC1
added, boiled on a water bath for 1 hour. It would be allowed to cool and the pH would
be adjusted to 60 using NaOH. NHCL would be added to lower the pH then filtered in a
100ml flask. 1ml of acetic would be added, mixed properly with 0.5ml of 3% KMn04
solution. After 2minutes 0.5ml of 3% H added and mixed well. The
flourimeter would be adjusted to excitation wave length of 470nm and emission
wavelength of 525nm. The fluorescence of the tube would be measured.
Calculation
Suppose W = Weight of sample
X- (reading of sample l)-(reading of sample blank)
Y= (reading of sample + standard tube 2)-(reading
of sample + standard blank)

27. 27
Riboflavin (mg per g of sample) = x X 1
Y w.
3.6.3 Determination of thiamin
The food material was treated with dilute HCL to extract thiamin which would be
then treated with phosphate to liberate free thiamin. It would be purified by passing it
through base exchange silicase alkaline column to remove interfering compounds. The
column would be eluted with ferricyanide to oxidize thiamine to thiochrom which would be
measured flourometrically. Calculation.
X = (Reading of sample solution)-(reading of blank) Y = (Reading
of the standard)-(reading of standard blank) V = Volume of solution
used for test on the column
Then content of Thiamin = x 1 x 25 x 100
Y 5 v wt of sample
3.7 Sensory evaluation
Sensory evaluations of the texture, flavor (aroma), taste and color (Appearance) were
carried out using 20 panelists of undergraduate students of Michael Okpara University of
Agriculture, Umudike.
This was done using the 7 point hedonic scale shown below;
7 - Liked extremely
6 - Liked moderately
5. - Liked slightly
4. - Neither liked nor disliked

28. 28
3. - Slightly disliked
2. - Moderation disliked
1. - Extremely disliked
3.8 Statistical analysis
Data from the study which included the nutrient content, and sensory
evaluation were subjected to analysis of variance (ANOVA), the means where
separated by Duncan multiple range test using IBM (SPSS version 20). Significance
was accepted at p<0.05.

29. 29
CHAPTER 4
RESULT AND DISCUSSION
4.1 Production of Bread from Corn and Watermelon seed flour
Figure 2
Figure 2 shows the bread produced from a combination of Corn and watermelon seed flour.
The products from various proportion all turned out fine, however due to the absence
of gluten contained by wheat flour and the presence of the watermelon seed oils, the
product was observed to have a bread cake texture and did not raise, however the
change in the color couldbe as a result of excessive heat employed in their production.

30. 30
4.2 Proximate composition of breads
Table 4.1 below showed the proximate composition of the bread produced from
watermelon seed and corn flour. Increase in crude protein due to increase in the proportion
of watermelon seed flour has been reported by several authors (USDA, 2014; Zohary and
Hopf, 2000 and Mandel, 2005; Motes et al., 2005). The fat content also increased with the
increase in the proportion of watermelon seed flour as identified by several authors
(USDA, 2014; Zohary and Hopf, 2000 and Mandel, 2005; Motes et al., 2005). The ash
content also increased with the increase in the proportion of watermelon seed flour as
identified by several authors (USDA, 2014; Zohary and Hopf, 2000; Mandel, 2005; Motes
et al., 2005). The fiber content was found to decrease with the decrease in the watermelon
seed flour as watermelon seeds are low in carbohydrate as identified by (Parsons, 2000;
Mossler, 2007). The carbohydrate content was found to increase with decrease in the
watermelon seed flour (USDA, 2014) which also reports same as Mossler, 2007.
Table 4.1: proximate composition of bread samples
SAMPLE C.PROTEIN C.FAT MOISTURE ASH C.FIBRE CHO
70-30
Wms-
corn
10.52a
±0.03
12.73a
±0.42
9.34c
±0.08
4.32a
±0.06
6.33a
±0.10
56.76c
±0.17
50-50
Wms-
corn
10.13b
±0.01
11.60b
±0.03
12.61a
±0.13
3.43b
±0.10
5.77b
±0.05
56.47c
±0.26
30-70
Wms-
corn
9.86c
±0.01
8.70c
±0.03
12.09b
±0.13
3.03c
±0.04
5.23c
±0.04
61.09b
±0.17
Corn
flour
5.89d
±0.04
6.48d
±0.03
8.87d
±0.10
2.16d
±0.02
4.17d
±0.02
72.44a
±0.16
Values are means ± standarddeviationof duplicatesamples
a-d
Means with similar superscripts in the samecolumnare not significantlydifferent (P>0.05).

31. 31
Key:
70% watermelon seed flour – 30% corn flour
50% watermelon seed flour – 50% corn flour
30% watermelon seed flour - 70% corn flour
100% corn flour (control)
The protein content in sample 70% watermelon seed- 30% corn(10.52a±0.03) was
significantly higher (P<0.05) than the protein content in the other samples, 50%
watermelon seed- 50% corn(10.13b±0.01), 30% watermelon seed- 70% corn(9.86c±0.01)
and 100% corn (5.89d±0.04). These suggest that the watermelon seed is an oil seed rich in
protein, hence may be utilized as high energy, protein and oil sources. Although crude
protein and lipid of the seeds of Citrullus lanatus showed lower values than the previously
published work, Adeyeye (2004), and Aremu et al. (2006). the relative values obtained
indicates that these seeds have nutritional quality favorably comparable with other oil seeds
and may be utilized as high protein and oil sources in some food formulation for human
consumption. The fat content in sample 70% watermelon seed- 30% corn(12.73a±0.42)
was significantly higher (P<0.05) than the fat content in the rest samples, 50% watermelon
seed- 50% corn (11.60b±0.03), 30% watermelon seed- 70% corn (8.70c ±0.03) and 100%
corn (6.48d±0.03). The moisture content in sample 50% watermelon seed- 50%
corn(12.61a±0.13) was significantly higher (P<0.05) than the moisture content in the other
samples, 70% watermelon seed- 30% corn (9.34c ±0.08), 30% watermelon seed- 70% corn
(12.09b±0.13) and 100% corn (8.87d ±0.10) The moisture content of the bread products is
lower than that of the processed and unprocessed Dioscorea dumetorum (Egbuonu et al.,
2014a) The lower moisture could enhance storage stability (Ejikeme et al., 2010;
Bamigboye et al., 2010; Nzewi and Egbuonu, 2011) of the bread product. The crude fiber

32. 32
in sample 70% watermelon seed- 30% corn (6.33a±0.10) was significantly higher (P<0.05)
than the crude fiber of the other samples, 50% watermelon seed- 50% corn (5.77b±0.05),
30% watermelon seed- 70% corn (5.23c±0.04) and 100% corn (4.17d ±0.02). Fiber contents
of bread samples compare with the value (1.90±0.08%) reported by Fila et al. (2013).
The carbohydrate content in sample 100% corn (72.44a±0.16) was significantly higher
(P<0.05) than the carbohydrate content in the other samples, 70% watermelon seed- 30%
corn (56.76c ±0.17), 50% watermelon seed- 50% corn (56.47c±0.26), 30% watermelon
seed- 70% corn (61.09b±0.17). However there was no significant difference (P>0.05) in the
carbohydrate content between samples 70% watermelon seed- 30% corn(56.76c ±0.17) and
50% watermelon seed- 50% corn(56.47c ±0.26). The carbohydrate content of the rind is
higher while that of the seed is lower than the values for Pachira glabra (52.32±0.8%) and
Afzelia africana (45.92±0.72%) reported by Ogunlade et al. (2011).
4.3 Mineral composition of breads
The sodium content in the sample with 70% watermelon seed and 30% corn (124.5±0.19)
was significantly higher (P<0.05) than the sodium content in the other samples, 50%
watermelon seed- 50%corn (120.8±0.09), 30%watermelon seed-70%corn (120.6±0.10),
100% corn (117.6c±0.03). There was no significant difference (P>0.05) in the sodium
content of samples 50% watermelon seed- 50% corn (120.8b±0.09) and 30% watermelon
seed- 70% corn (120.6b±0.10), the sodium content were comparable with values obtained
by (El-Adawy and Taha, 2001 Ojieh et al.,2007). The potassium content in sample 70%
watermelon seed- 30% corn (1048.4a±0.31) was significantly higher than the potassium

33. 33
content in the other samples, 50% watermelon seed- 50% corn (1018.7b±0.06), 30%
watermelon seed- 70% corn (998.6c±0.06) and 100% corn (987.6d±0.04), this was slightly
higher than values reported by (El-Adawy and Taha, 2001; ojieh et al.,2007).The
magnesium content in sample 70% watermelon seed- 30% corn(385.5a±0.06) was
significantly higher (P<0.05) than the other samples, 50% watermelon seed- 50% corn
(380.6b±0.07) 30% watermelon seed- 70% corn (376.5c±0.06) and (358.2d±0.04), this
values were lower than values reported by (El-Adawy and Taha, 2001) but higher than
values reported by (Ojieh et al.,2007), for other melon products. The calcium content in
sample 70% watermelon seed- 30% corn (72.52a±0.08) was significantly higher (P<0.05)
than the calcium content in the other samples, 50% watermelon seed- 50% corn
(68.70b±0.15), 30% watermelon seed- 70% corn (65.39c±0.04) and 100% corn
(57.87d±0.05), this values were in accordance with values reported by (El-Adawy and
Taha, 2001) but higher than reported by (Ojieh et al.,2007), for other melon products. The
phosphorus content in 70% watermelon seed- 30% corn (24.36a±0.08) was significantly
higher (P<0.05) than the other samples, 50% watermelon seed- 50% corn (22.55b±0.06),
30% watermelon seed- 70% corn (20.85c±0.03) and 100% corn (17.54d±0.08), this values
were lower than values reported by (El-Adawy and Taha, 2001; Ojieh et al.,2007) for other
melons.

34. 34
Table 4.2: Mineral content of bread samples
SAMPLES SODIUM POTASSIUM MAGNESSIUM CALCIUM PHOSPHORUS
70%- 30%
wms-corn 124.5a±0.19 1048.4a±0.31 385.5a±0.06 72.52a±0.08 24.36a±0.08
50%- 50%
Wms-corn 20.8b±0.09 1018.7b±0.06 380.6b±0.07 68.70b±0.15 22.55b±0.06
30%- 70%
Wms-corn 120.6b±0.10 998.6c±0.06 376.5c±0.06 65.39c±0.04 20.85c±0.03
100% corn 117.6c±0.03 987.6d±0.04 358.2d±0.04 57.87d±0.05
17.54d±0.08
Values are means ± standarddeviationof duplicatesamples
a-d
Means of similar superscripts in the same column are not significantly different.
Key:
70% watermelon seed- 30% corn
50% watermelon seed- 50% corn
30% watermelon seed- 70% corn
100% corn (control)
4.4 Vitamin composition of breads
The vitamin B1 content in sample 70% watermelon seed- 30% corn(0.22a ± 0.00) was
significantly higher (P<0.05) than the vitamin B1 content in the other samples, 50%
watermelon seed- 50% corn (0.21b±0.20), 30% watermelon seed- 70% corn(0.20c±0.00),
and 100% corn (0.18d±0.00). The vitamin B2 content in the samples ranged from 0.02 –
0.05, with sample 70% watermelon seed- 30% corn (0.05a±0.00) mean score significantly
higher (P<0.05) than the rest samples, 50% watermelon seed- 50% corn (0.04ab±0.00),
30% watermelon seed- 70% corn (0.037b±0.001) and 100% corn (0.02c±0.01). The vitamin
B3 content in sample 70% watermelon seed- 30% corn (2.43a±0.01) was significantly
higher (P<0.05) than the rest samples 50% watermelon seed- 50% corn (2.36b±0.01), 30%

35. 35
watermelon seed- 70% corn (2.31c±0.01), and 100% corn (2.26d±0.02). The vitamin C
content of the samples ranged from 15.84 – 16.40, with sample 70% watermelon seed-
30% corn (16.40a±0.03) score significantly higher (P<0.05) than the rest samples 50%
watermelon seed- 50% corn (16.30b±0.00), 30% watermelon seed- 70% corn (16.26b±0.01)
and 100% corn (15.84c±0.28).however there was no significant difference (P>0.05) in the
mean score of samples 50% watermelon seed- 50% corn (16.30b±0.00) and 30%
watermelon seed- 70% corn (16.26b±0.01)
Table 4.3: Vitamin content of bread samples
SAMPLES VIT.B1 VIT.B2 VIT.B3 VIT.C
70%- 30%
Wms-corn 0.22a±0.00 0.05a±0.00 2.43a±0.01 16.40a±0.03
50%- 50%
Wms-corn 0.21b±0.20 0.04ab±0.00 2.36b±0.01 16.30b±0.00
30%- 70%
Wms-corn 0.20c±0.00 0.04b±0.00 2.31c±0.01 16.26b±0.01
100% corn 0.18d±0.00 0.02c±0.01 2.26d±0.02 15.84c±0.28
Values are means ± standarddeviationof duplicatesamples
a-d
Means of similar superscripts in the samecolumnare not significantlydifferent (P>0.05).
Key:
70% watermelon seed- 30% corn
50% watermelon seed- 50% corn
30% watermelon seed- 70% corn
100% corn (control).
4.5 Sensory properties of breads
The mean score of sample 70% watermelon seed- 30% corn (7.0a±1.44) in terms of taste,
was significantly higher (P<0.05) than the mean score of the rest samples 50% watermelon
seed- 50% corn (6.40ab±1.38), 30% watermelon seed- 70% corn (6.03b±2.19), and 100%
corn (6.83ab±1.76). There was no significant difference (P>0.05) in the mean score of

36. 36
samples 50% watermelon seed- 50% corn (6.40ab±1.38) and 100% corn (6.83ab±1.76) in
terms of taste.
No significant difference (P>0.05) was observed in the appearance of samples 70%
watermelon seed- 30% corn (6.90 b ± 1.30) and 50% watermelon seed- 50% corn (6.9 b ±
1.45). The mean score of the appearance of sample 100% corn (7.7a± 0.99) was
significantly higher (P<0.05) than the mean score of the rest samples, 70% watermelon
seed- 30% corn (6.90b± 1.30), 50% watermelon seed- 50% corn (6.90b± 1.45) and 30%
watermelon seed- 70% corn (5.97c ± 1.97).
There was no significant difference (P>0.05) in the texture of all the samples, 70%
watermelon seed- 30% corn (6.10a± 1.63), 50% watermelon seed- 50% corn (6.67 a ± 2.01)
30% watermelon seed- 70% corn (5.83a ± 2.32) and 100% corn (6.83a ± 1.56).
The general acceptability of sample 70% watermelon seed- 30% corn (7.17a±1.70) was
significantly higher (P<0.05) than the general acceptability of the rest samples, 50%
watermelon seed- 50% corn(7.03ab±1.43), 30% watermelon seed- 70% corn (6.13b± 2.11)
and 100% corn (7.03ab± 1.75). However, there was no significant difference (P>0.05) in
the mean scores of the general acceptability of samples 50% watermelon seed- 50% corn
(7.03ab±1.43) and 100% corn (7.03ab±1.75).

37. 37
Table 4.4: Sensory of bread sample
SENSORY ANALYSIS
SAMPLES TASTE APPEARANCE TEXTURE GA
70%
watermelon
seed- 30%
corn
7.000a ± 1.44 6.900 b ± 1.30 6.100 a ± 1.63 7.167 a ± 1.70
50%
watermelon
seed- 50%
corn
6.400ab ± 1.38 6.900 b ± 1.45 6.667 a ± 2.01 7.033 ab ± 1.43
30%
watermelon
seed- 70%
corn
6.033b ± 2.19 5.967c ± 1.97 5.833 a ± 2.32 6.133 b ± 2.11
100% corn 6.833ab ± 1.76 7.700 a ± 0.99 6.833 a ± 1.56 7.033 ab ± 1.75
Values are means ± standarddeviationof duplicatesamples
a-c
Means with similar superscripts in the same column arenot significantly different (P>0.05).
Key:
70% watermelon seed- 30% corn
50% watermelon seed- 50% corn
30% watermelon seed- 70% corn
100% corn (control)

38. 38
CHAPTER 5
CONCLUSION AND RECOMMENDATION
5.1 Conclusion
From the results obtained in this study, sample 70% watermelon seed- 30% corn(70%
watermelon seed flour and 30% corn flour) showed the highest mean score of crude
protein, fat, ash, and fiber while sample 100% corn(100% corn flour) showed the lowest.
The carbohydrate content in sample 70% watermelon seed- 30% corn was found to be
lower than that in sample 100% corn, but however sample 70% watermelon seed- 30%
corn scored the highest in terms of energy making it a good source of energy for adults and
endurance athletes and can also be employed in management of diabetes and obesity. Thus
the high concentration of amino acids, makes watermelon seeds suitable for
supplementation of foods.
5.2 Recommendation
 Utilization of watermelon seeds in bakery and confectionaries.
 Improved consumption by individuals as it is a good source of protein.