PHYSICO-CHEMICAL PROPERTIES OF WATERMELON

SEEDS FLOUR AND ITS USE IN BISCUITS MAKING

BY

Marwa Faroug Alrayah Ali

B. Sc (Agric. Honours)-2003 University of Khartoum

A dissertation submitted to University of Khartoum in partial fulfillment for the requirements of the degree of Master of Science in Food Science and Technology

SUPERVISOR Prof. Abdelmoneim Ibrahim Mustafa

DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY FACULTY OF AGRICULTURE

UNIVERSITY OF KHARTOUM July2006

Dedication

To my parents who really deserve my utmost respect and regards. To my Dear sister and friends.

Acknowledgements

First and foremost I thank almighty Allah for endowing me the patience to fulfill this dissertation.

Then I should pass thanks to my learned supervisor professor Abdelmoneim Ibrahim Mustafa to whom I am most indebted for the precious advice and the sincere efforts he exerted with me, particularly, for allowing me much of his valuable time revising and correcting the chapters of this dissertation.

My deep gratitude to all staff of the Food Technology Research Institute, Agricultural Research Center (cairo), particularly, Dr. Saeed Mansour and Dr. Salah Hamza, for their help.

Also I move avote of thanks to Dr. Gammaa A. Osman for his continuous interest and useful suggestions.

Finally, I record my thanks to my family, friends and colleagues for the continued encouragement to pursue this effort.

ABSTRACT

Watermelon (Citrullus vulgaris) seeds and patent flour from a mixture (Australian and American wheats) were used in this study. Proximate analysis, minerals, tannins and phytic acid contents, were carried for wheat and watermelon seed flours. Amino acids profile had been done for watermelon seeds flour. Rheological properties were studied for wheat flour with 0, 5, 10 and 15%watermelon seeds flour. The results of the proximate analysis showed that, ash (2.97%), protein (20.61%), fat (30.50%) and fiber (33.52%) for watermelon seeds flour were significantly higher than for the wheat flour 0.507, 11.05, 1.43, 0.15%, respectively. The wheat flour carbohydrate (76.79%) was higher than the watermelon seed flour (7.31%). Ca, K, Na, Fe ,Mn and Zn (42.09,18.86,33.58,3.42,1.47,3.22mg/100g, respectively)in watermelon seeds flour were higher than in wheat

flour(20.24,7.25,3.44,0.82,0.75,0.85mg/100g,respectively), but the wheat flour had

higher content of Mg (270.55 mg/100g) than watermelon seeds flour (232.41 mg/100g).

No significant difference between the two types of flours wheat and watermelon seeds in tannin content15.0and16.7mg/100g,respectively. The phytic acid content of melon seed flour (1445.33 mg/100g) was higher than for wheat flour (126.00 mg/100g). Lysine and methionine were the limiting amino acids while glutamic acid was marginal in watermelon seeds flour. The addition of watermelon seed flour affected the rheology of the wheat flour as reflected in the farinogram and extensogram. As the percentage of watermelon seeds flour increased, the energy and resistance decreased,but extensibility increased, showing softer dough. The quality evaluation for biscuits made from wheat flour with watermelon seeds flour (15%) addition had the highest spread ratio (10.9). The overall quality evaluation of biscuits made from wheat flour and watermelon seeds flour showed high acceptability, wheat flour blended with10%watermelon seeds flour showed best biscuits.

ﺑﺴﻢ ﺍﷲ ﺍﻟﺮﺣﻤﻦ ﺍﻟﺮﺣﻴﻢ ﺨﻼﺼﺔ ﺍﻷﻁﺭﻭﺤﺔ

ﺃﺠﺭﻴﺕ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺒﺎﺴﺘﺨﺩﺍﻡ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﺍﻟﻜﺎﻤﻠﺔ ﻭﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ ﺍﻟﻔﺎﺨﺭ (ﺨﻠﻴﻁ ﻗﻤـﺢ ﺍﺴﺘﺭﺍﻟﻲ ﻭﺃﻤﺭﻴﻜﻲ ). ﺘﻡ ﺇﺠﺭﺍﺀ ﺍﻟﺘﺤﻠﻴل ﺍﻟﺘﻘﺭﻴﺒﻲ، ﻭﺘﻘﺩﻴﺭ ﻤﺤﺘﻭﻱ ﺍﻟﻤﻌﺎﺩﻥ، ﺍﻟﺘﺎﻨﻴﻨﺎﺕ ﻭﺤﻤﺽ ﺍﻟﻔﺎﻴﺘﻴﻙ ﻟﻜل ﻤﻥ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﻭﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ، ﻜﻤﺎ ﺘﻡ ﺘﻘ ﺩﻴﺭ ﺍﻷﺤﻤﺎﺽ ﺍﻷﻤﻴﻨﻴﺔ ﻟﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ . ﺘﻤﺕ ﺩﺭﺍﺴﺔ ﺍﻟﺨﻭﺍﺹ ﺍﻟﺭﻴﻭﻟﻭﺠﻴﺔ ﻟﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ ﻤﻊ ﺇﻀﺎﻓﺔ 0، 5، 10 ﻭ15% ﻤﻥ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ.

ﺃﻭﻀﺤﺕ ﻨﺘﺎﺌﺞ ﺍﻟﺘﺤﻠﻴل ﺍﻟﺘﻘﺭﻴﺒﻲ ﺃﻥ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﻴﺤﺘـﻭﻱ ﻋﻠـﻰ (2.97%) ﺭﻤـﺎﺩ، (20.61%) ﺒﺭﻭﺘﻴﻥ، (30.5%) ﺩﻫﻥ، ﻭ (33.52%) ﺍﻟﻴﺎﻑ. ﻭﻜﺎﻨﺕ ﻫﺫ ﻩ ﺍﻟﻨﺘﺎﺌﺞ ﺃﻋﻠﻰ ﻤﻌﻨﻭﻴﺎﹰ ﻤـﻥ ﻨﻅﻴﺭﺍﺘﻬﺎ ﻓﻲ ﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ . ﻜﻤﺎ ﺃﻭﻀﺤﺕ ﺍﻟﻨﺘﺎﺌﺞ ﺃﻥ ﺍﻟﻜﺭﺒﻭﻫﻴﺩﺭﺍﺕ ﻟﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ (76.79%) ﺃﻋﻠـﻲ ﻤﻥ ﻨﻅﻴﺭﺘﻬﺎ ﻓﻲ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ (%7.31).

ﻟﻘﺩ ﺃﺘﻀﺢ ﺃﻥ ﻤﺤﺘﻭﻱ ﺍﻟﻜﺎﻟﺴﻴﻭﻡ، ﺍﻟﺒﻭﺘﺎﺴﻴﻭﻡ، ﺍﻟﺼﻭﺩﻴﻭﻡ، ﺍﻟﺤﺩﻴﺩ، ﺍﻟﻤﻨﺠﻨﻴﺯ ﻭﺍﻟﺯﻨﻙ ﺃﻋﻠـﻰ ﻓﻲ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﻤﻘﺎﺭﻨﺔ ﺒﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ، ﺒﻴﻨﻤﺎ ﻭﺠﺩ ﻤﺤﺘﻭﻱ ﺍﻟﻤﻐﻨﻴﺴﻴﻭﻡ ﺃﻋﻠﻲ ﻓﻲ ﺩﻗﻴـﻕ ﺍﻟﻘﻤـﺢ (mg/100g 270.55) ﻤﻘﺎﺭﻨﺔ ﺒﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ (mg/100g 232.41).

ﻭﻟﻘﺩ ﺃﻭﻀﺤﺕ ﺍﻟﺩﺭﺍﺴﺔ ﻋﺩﻡ ﻭﺠﻭﺩ ﻓﺭﻭﻗﺎﺕ ﻤﻌﻨﻭﻴﺔ ﺒﻴﻥ ﻨﻭﻋﻲ ﺍﻟﺩﻗﻴﻕ ﻓﻲ ﻤﺤﺘﻭﻱ ﺍﻟﺘﺎﻨﻴﻨﺎﺕ، ﺒﻴﻨﻤﺎ ﻭﺠﺩ ﺤﻤﺽ ﺍﻟﻔﺎﻴﺘﻴﻙ ﺃﻋﻠﻲ ﻓﻲ ﺩﻗﻴﻕ ﺒﺩﺭﺓ ﺍﻟﺒﻁﻴﺦ (mg/100g 1445.33) ﻤﻘﺎﺭﻨﺔ ﺒﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﻘﻤـﺢ (mg/100g 126). ﻜﻤﺎ ﺃﺘﻀﺢ ﻤﻥ ﺘﻘﺩﻴﺭ ﺍﻻﺤﻤﺎﺽ ﺍﻷﻤﻴﻨﻴـﺔ ﺃﻥ ﺤﻤـﻀﻲ ﺍﻟﻤﻴﺜﻴـﻭﻨﻴﻥ ﻭﺍﻟﻼﻴﺴﻴﻥ ﺃﻗﻠﻬﺎ ﻨﺴﺒﺔ ﺒﻴﻨﻤﺎ ﺤﻤﺽ ﺍﻟﺠﻠﻭﺘﻤﻴﻙ ﺃﻋﻼﻫﺎ ﻨﺴﺒﺔ.

ﻟﻘﺩ ﺃﻭﻀﺤﺕ ﺍﻟﻨﺘﺎﺌﺞ ﺍﻟﻤﺄﺨﻭﺫﺓ ﻤﻥ ﺍﻟﻔﺎﺭﻴﻨﻭﺠﺭﺍﻡ ﻭﺍﻻﻜﺴﺘﻨﺴﻭﻏﺭﺍﻡ ﺃﻥ ﺇﻀﺎﻓﺔ ﺩﻗﻴـﻕ ﺒـﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﺃﺜﺭ ﻋﻠﻰ ﺍﻟﺨﻭﺍﺹ ﺍﻟﺭﻴﻭﻟﻭﺠﻴﺔ ﻟﻌﺠﻴﻨﺔ ﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ . ﻭﻟﻘﺩ ﺍﺘﻀﺢ ﺃﻨـﻪ ﻜﻠﻤـﺎ ﺯﺍﺩﺕ ﺍﻟﻨـﺴﺒﺔ ﺍﻟﻤﺌﻭﻴﺔ ﻟﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﻓﻲ ﻋﺠﻴﻨﺔ ﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ ﻜﻠﻤﺎ ﻨﻘﺼﺕ ﺍﻟﻁﺎﻗﺔ ﻭﺍﻟﻤﻘﺎﻭﻤﺔ ﻭﺯﺍﺩ ﺍﻟﺘﻤﺩﺩ ﻤﻤـﺎ ﻴﻭﻀﺢ ﻀﻌﻑ ﺍﻟﻌﺠﻴﻨﺔ.

ﺘﻘﻴﻴﻡ ﺠﻭﺩﺓ ﺍﻟﺒﺴﻜﻭﻴﺕ ﺍﻟﻤﺼﻨﻊ ﻤﻥ ﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ ﻭﺇﻀﺎﻓﺎﺕ ﺩﻗﻴﻕ ﺒﺫﺭﺓ ﺍﻟﺒﻁـﻴﺦ ﺃﻭﻀـﺢ ﺃﻥ ﺍﻹﻀﺎﻓﺔ 15% ﺃﻋﻁﺕ ﺃﻋﻠﻲ ﻤﻌﺩل ﺇﻨﺘﺸﺎﺭ (10.9).

ﺍﻟﺘﻘﻴﻴﻡ ﺍﻟﻜﻠﻲ ﻟﺠﻭﺩﺓ ﺍﻟﺒﺴﻜﻭﻴﺕ ﺍﻟﻤﺼﻨﻊ ﻤﻥ ﺩﻗﻴﻕ ﺍﻟﻘﻤﺢ ﻭﺒﺫﺭﺓ ﺍﻟﺒﻁﻴﺦ ﺃﻅﻬﺭ ﻗﺒـﻭل ﻋـﺎﻟﻲ، ﻭﺃﻋﻠﻲ ﻨﺴﺒﺔ ﻗﺒﻭل ﻅﻬﺭﺕ ﻓﻲ ﺍﻹﻀﺎﻓﺔ (%10).

LIST OF CONTENTS

Page DEDICATION...... i ACKNOWLEDGEMENT...... ii ABSTRACT...... iii ARABIC ABSTRACT...... v LIST OF CONTENTS...... vi LIST OF TABLES...... x LIST OF FIGURES...... xi LIST OF PLATES...... xii

CHAPTER ONE: INTRODUCTION...... 1 CHAPTER TWO: LITERATURE REVIEW...... 3 2.1. Wheat composition...... 3 2.1.1. Chemical composition...... 4 2.1.1.1. Moisture content...... 4 2.1.1.2. Ash content...... 4 2.1.1.3. Protein content...... 5 2.1.1.4. Fat content...... 6 2.1.1.5. Fiber content...... 6 2.1.1.6. Carbohydrates...... 7 2.1.2. Minerals content...... 7 2.1.3. Amino acids content...... 8 2.1.4. Anti-nutritional factors...... 9 2.1.4.1. Phytic acid...... 9 2.1.4.2. Tannins...... 10 2.2. Watermelon seeds...... 10 2.2.1. Botanical features of the plant and distribution...... 10 2.2.2. Plant requirements...... 11 2.2.3. Uses of watermelon seeds...... 11 2.2.4. Chemical composition of watermelon seeds...... 12 2.2.4.1. Moisture content...... 12 2.2.4.2. Protein content...... 12 2.2.4.3. Fat content...... 13 2.2.4.4. Fiber content...... 14 2.2.4.5. Carbohydrates...... 14 2.2.4.6. Ash content...... 15 2.2.5. Minerals content...... 15 2.2.6. Amino acids...... 16 2.2.7. Anti-nutritional factors...... 17 2.2.7.1. Phytic acid...... 17 2.2.7.2. Tannins...... 18 2.3. Rheological characteristics...... 18 2.4. Composite flour...... 20 2.5. Biscuit making...... 22 2.5.1. Biscuit ingredients...... 22 2.5.2. and forming of biscuits...... 24 2.5.3. ...... 25 2.6. Biscuit of composite flour...... 25 CHAPTER THREE: MATERIALS AND METHODS...... 27 3.1. Materials...... 27 3.2. Methods...... 27 3.2.1. Sample preparation...... 27 3.2.2. Proximate analysis...... 27 3.2.2.1. Determination of moisture content...... 29 3.2.2.2. Determination of ash...... 29 3.2.2.3. Determination of crude protein...... 30 3.2.2.4. Determination of fat (ether extraction)...... 30 3.2.2.5. Determination of crude fiber...... 31 3.2.2.6. Determination of carbohydrates...... 31 3.2.3. Determination of minerals content...... 32 3.2.4. Determination of anti-nutritional factors...... 32 3.2.4.1. Determination of tannins content...... 32 3.2.4.2. Determination of phytic acid content...... 33 3.2.5. Determination of amino acids content...... 34 3.2.6. Rheological properties of dough...... 35 3.2.6.1. Farinograph characteristics...... 35 3.2.6.1.1. The titration curve...... 35 3.2.6.1.2. The standard curve...... 36 3.2.6.2. Extensigraph characteristics...... 37 3.2.7. Preparation of biscuits...... 37 3.2.7.1. Method...... 39 3.2.7.2. Sensory evaluation of biscuits...... 39 3.2.8. Statistical analysis...... 39 CHAPTER FOUR: RESULTS AND DISCUSSION...... 41 4.1. Chemical composition of wheat and watermelon seed flours...... 41 4.1.1. Moisture content...... 41 4.1.2. Ash content...... 41 4.1.3. Protein content...... 42 4.1.4. Fat content...... 42 4.1.5. Fiber content...... 43 4.1.6. Carbohydrates...... 43 4.2. Minerals content...... 46 4.3. Anti-nutritional factors...... 46 4.3.1. Phytic acid content...... 46 4.3.2. Tannins content...... 48 4.4. Amino acids content...... 48 4.5. Rheological characteristics...... 51 4.5.1. Farinogram characteristics...... 51 4.5.2. Extensogram characteristics...... 57 4.6. Organoleptic quality of biscuits...... 64 4.6.1. Color...... 64 4.6.2. Odor...... 64 4.6.3. Surface feel...... 64 4.6.4. Taste...... 65 4.6.5. Mouth feel...... 65 4.6.6. Texture...... 65 4.6.7. Total score...... 65 4.7. Biscuits made from composite flours...... 68 4.7.1.Width...... 68 4.7.2.Thickness...... 68 4.7.3 Spread ratio...... 68 CHAPTER FIVE: CONCLUSIONS AND RECOMMENDATION.. 71 REFERENCES...... 73

LIST OF TABLES Page Table 1. Chemical composition of watermelon seeds and wheat flour.. 45 Table 2. Minerals in wheat flour and watermelon seeds...... 47 Table 3. Tannins and phytic acid in wheat flour and watermelon seeds. 49 Table 4. Amino acids profile of watermelon seeds flour...... 50

Table 5. Farinogram readings of wheat flour with watermelon seed flour...... 52. Table 6. Extensogram readings of wheat flour with watermelon seed flour...... 59 Table 7. Quality attributes of biscuit...... 67 Table 8. Physical characteristics of biscuit...... 69 LIST OF FIGURES Page Fig. 1. Panel test for biscuit samples(Hedonic)………………… 40 Fig. 2. Farinogram of wheat flour (control)...... 53 Fig. 3. Farinogram of wheat flour with 5% watermelon seed flour. 54 Fig. 4. Farinogram of wheat flour with 10% watermelon seed flour. 55 Fig. 5. Farinogram of wheat flour with 15% watermelon seed flour. 56 Fig. 6. Extensogram of wheat flour (control)...... 60 Fig. 7. Extensogram of wheat flour with 5% watermelon seed flour. 61 Fig. 8. Extensogram of wheat flour with 10% watermelon seed flour. 62 Fig. 9. Extensogram of wheat flour with 15% watermelon seed flour. 63

LIST OF PLATES Page Plate 1. watermelon seeds...... 28 Plate 2. wheat flour and watermelon seeds flour...... 28 Plate 3. Biscuits made from wheat and watermelon seed composite flours...... 70

CHAPTER ONE INTRODUCTION

The world population is now increasing at a very high rate, whether this rate of increase will sustain or not, the fact remains that such rate itself is currently accelerating. Such a rate of increase introduces many problems; however the most urgent one is the supply of food. Theoretically, the parts of the world that produce surplus food could makeup the shortfall in the needy parts, but this is not a satisfactory long term solution. In many third world countries, even if the people do get enough to eat in terms of energy content, their diets are unbalanced and lack necessary proteins and vitamins. These people will suffer from malnutrition even though they are not starving. Cereals are important source of energy and protein in the human diet. Although carbohydrates are their main dietary contribution, they also provide proteins and smaller amounts of lipids, fiber and vitamins. It is commonly known that the main nutritional drawback in cereals, is their low protein content and the limited biological quality of their proteins, when compared with proteins found in animals. Nevertheless, the protein quality found in a given cereal can be improved by combining it with other sources of proteins. In many developing countries, the supply of animal protein is inadequate to meet the protein needs of the rapidly growing population. This has necessitated contemporary research efforts geared towards the study of the food properties and potential utilization of proteins from locally available food crops, especially from underutilized or relatively neglected high protein oilseeds and legumes. One of the locally available oilseeds in Sudan is watermelon seeds, which is grown extensively as a rain fed crop, mainly for its water content and not as a desert fruit, as it is usual in other parts of the world. It is envisaged that a study of its nutritive value and limitations may enhance its use in effectively meeting part of the protein needs. Biscuits are widely accepted and consumed in many developing countries. They offer available vehicle for supplementation with watermelon seeds flour for nutritional improvement.

The objectives of this research are:- 1. To determine the nutritional value of watermelon seeds flour and to compare it with the nutritional value of wheat flour. 2. To determine the anti-nutritional factors of watermelon seeds flour 3. To study the effect of different levels of addition of watermelon seed flour on the rheological characteristics of wheat flour dough. 4. To compare the physical and sensory properties of wheat flour biscuits in relation to watermelon seed flour - fortified biscuits.

CHAPTER TWO LITERATURE REVIEW 2.1. Wheat composition Wheat is the most popular cereal grain for the production of bread and cakes and other pastries. The unique properties of wheat protein alone can produce bread of the strength and elasticity required to produce low- density bread and pastries of desirable texture and flavor (Vieira, 1996). There are many varieties of wheat, they may be classified as hard red winter wheats, hard red spring wheats, soft red winter wheats, white wheats and durum wheats. Winter wheats are planted in the fall and harvested in the late spring or early summer. Spring wheats are planted in the spring and harvested in the late summer. Hard wheats are higher in protein content and produce more elastic doughs than soft wheats. Therefore, hard wheats are used for breads, and soft wheats are used for cakes. Durum wheats are used most for pasta products e.g. spaghetti, macaroni,… etc. and for the thickening of canned soups (Vieira, 1996). Variation in quality of wheat flours may be due to the type of wheat used, the conditions under which the wheat was grown, the size of the flour particles, the completeness of the milling, and the substances added during the milling (Stevenson and Miller, 1960). The chemical composition of wheat and its milling products vary over fairly wide limits. Thus protein contents ranging from 7.0 to 18.0% have been encountered in American wheats, and variations of lower relative magnitude have been observed in their contents of carbohydrates, lipids, vitamins, minerals, etc (Pyler, 1973).

2.1.1. Chemical composition 2.1.1.1. Moisture content Moisture content has a direct economic importance. Wheat generally contains 14% moisture resulting in an ambient relative humidity suitable for the growth of insects and other microorganisms, whose presence will markedly reduce the grain quality (Williams, 1970; Zeleny, 1971). Kent-Jones and Amos (1967) calculated the moisture content of wheat flour (extraction 72%) as a range between 13.0-15.5%, however, Mohammed (2000) found that the moisture content of the flour of Sudanese cultivars Condor, Sasaraib, Elneilain and Debera range between 7.5 and 7.95%. Doxastakis et al. (2002) reported that the moisture content of wheat flour is 12.6%. Moreover, Pyler (1973) mentioned that the moisture content of wheat flour is 13.0%, while Giami et al. (2005) showed that the moisture content of wheat flour is 10.5%. 2.1.1.2 Ash content Ash content has been considered an important indicator of flour quality, although the ash content of the flour is not related to the final performance, but gives some indications of the miller’s skill and the degree of refinement in processing( Pratt, 1971). Kent-Jones and Amos (1967) reported the ash content of wheat flour in the range between 0.3-0.6%, while Doxastakis et al. (2002) reported that the ash content of wheat flour as 0.61%. And Pyler (1973) showed that it is 1.7% for the soft red winter wheat, which is the same with the white one. Giami et al. (2005) found that the ash content of wheat flour is 0.7%. Moreover, Badi et al. (1976) reported that the ash content of Sudanese flour is in the range between 0.38 and 0.84%. Mohammed (2000) calculated the ash content of four Sudanese wheat flours; Elneilain, Sasaraib, Condor and Debera ranging between 1.35 and 1.52%. 2.1.1.3 Protein content In general, a relatively low protein content is in the order of 9 to 13 percent. The proteins include glutelins , gliadins , globulins, albumins and proteases, of which the first two predominate and account for the characteristic gluten formation (Pyler, 1973). Gliadins are mainly responsible for the viscosity and extensibility of dough allowing it to rise during fermentation. Glutelins confer visco- elasticity to dough, the elastic component preventing it from becoming over extended and from collapsing either during fermentation or baking (Austin et al., 1965). Pyler (1973) reported that the various structural components of wheat differ not only in the amounts of protein they contain, but also in the kinds of proteins that are present. George (1973) mentioned that the protein content of the wheats is highly affected by environmental conditions, grain yield and available nitrogen as well as the variety genotype. Mohammed (2000) calculated the protein content of four Sudanese cultivars (Sasaraib, Condor, Eleneilain and Deberia) ranges between 12.29- 14.82%, while Badi et al. (1978) reported that the protein content of Sudanese wheat cultivars ranges between 11 and 14%. In addition, Giami et al. (2005) found that the protein content of wheat flour is 11.3%. And Doxastakis et al. (2002) showed that the protein content of wheat flour is 11.7%. Kent-Jones and Amos (1967) found that the protein content of wheat flour (extraction rate 72%) ranges between 8-13%, moreover Vieira (1996) showed that the protein content of whole-wheat flour is 13%, but 11%for the white flour. 2.1.1.4 Fat content Pyler (1973) reported that the lipids or fat like substances of wheat occur in amounts of 1-2 percent in flour, 8-15 percent in germ, about 6 percent in bran, and make up 2-4 percent of the whole wheat. Flour lipids are rather complex in composition, with as many as 23 individual components having been separated by thin-layer chromatography. Mohammed (2000) reported the fat content of four Sudanese wheat cultivars (Deberia, Elneilain, Condor and Sasaraib) as ranging between 2.15 and 2.35%. Kent-Jones and Amos (1967) found that the fat content of wheat flour (extraction 72%) ranges between 0.8-1.5%, while Giami et al. (2005) showed that the fat content of wheat flour is 0.7%. Doxastakis et al. (2002) illustrated that the fat content of wheat flour is 2.6%, however, Pyler (1973) mentioned that the fat content is 2.0% for the soft red winter wheat, as in the white one, which is 2.0%. 2.1.1.5 Fiber content The proportion of fiber is an indication of the extraction rate, the higher the rate of extraction (80, 85%, etc) the closer the flour is to whole meal (100%). In the case of wheat flour the lowest extraction (i.e. whitest flour) is normally 72 percent.(FAO,1986). Ranhotra et al. (1990) described fiber as total dietary fiber (TDF), which is defined as indigestible component in food, which includes cellulose, hemicelluloses, legnins, pectin and gum. The crude fiber content increases with the amount of branny matters present. Mohammed (2000) suggested that the crude fiber content of four Sudanese wheat cultivars (Sasaraib, Condor, Elneilain and Deberia) ranges between 2.10 and 2.85%, while Giami et al. (2005) found that the fiber content of wheat flour is 0.9%, but Kent-Jones and Amos (1967) showed that it is trace (0.2%) for the wheat flour (72% extraction). 2.1.1.6 Carbohydrates The principal carbohydrates of wheat are starch, dextrins, cellulose, pentosans and various types of free sugars, the latter being present in small amounts (Pyler, 1973). Humans derive their energy mainly from carbohydrates (55 to 65%), although they can also utilize fats and proteins for this purpose. The carbohydrates that are important in nutrition include sugars, starches, dextrins and glycogens. Others that are not digestible (the fibers) do not supply calories but are very important in the overall health and well being of the human body (Vieira, 1996). Giami et al. (2005) reported that the carbohydrate content of wheat flour is 75.9%, while Doxastakis et al. (2002) found that the carbohydrate content of wheat flour is 72.5%, whereas, Kent-Jones and Amos (1967) calculated the carbohydrate content of wheat flour (72% extraction) as arange between 65-70%. 2.1.2. Minerals content The human body consists of about 3% minerals, most of which are in the skeletal system. Minerals are generally categorized as “major” and “trace” based on the amounts in the body (Vieira, 1996). Wheat contains a considerable number of mineral constituents, which in their totality make up to the ash content of approximately 1.6 to 1.8 percent. The ash constituents of wheat are taken from the minerals of the soil, it is evident that both the total mineral content as well as the relative proportions of individual elements depend largely upon the soil, rainfall and other climatic conditions during growth. Analysis has shown that bran, on the whole, contains approximately 20 times as much ash as does the endosperm (Pyler, 1973). Giami et al. (2005) found that calcium, sodium, potassium, iron and phosphorous of wheat flour are 34.6, 20, 126.4, 0.2 and 86.2 (mg/100 g), respectively. However, the mineral content of commercial wheat flour analyzed by Pyler (1973) who found that K, P, Mg and Ca are 0.455, 0.380, 0.167 and 0.045%, but Na, Zn, Fe, Mn, Cu and Co are 12.8, 31.0, 37.3, 49.0, 4.0 and 0.024 ppm, respectively. 2.1.3. Amino acids content There are 20 amino acids, nine essential and eleven nonessential. Essential amino acids are those that cannot be synthesized by the body in adequate amounts and, therefore, must be supplied by the diet. The other amino acids are referred to as nonessential and can be made by the body. (Vieira, 1996). All proteins are composed of amino acids having the general formula: NH2 R-CH-COOH R could represent any one of a variety of chemical structures, the simplest being a hydrogen atom in glycine, whereas other amino acids have much more complex structure (Vieira, 1996). There are great differences in solubility among proteins. These differences are determined by the amino acid content and sequence. Except for two amino acids, lysine and tryptophan, most cereals contain the essential amino acids required by humans. And the wheat flour proteins are poor in lysine and relatively higher in the sulphur-containing amino acids (Bloksma and Bushuk, 1988). Williams (1970) suggested that the amino acid pattern of different varieties of wheat and of wheats from different parts of the world does not vary very greatly. Pyler (1973) reported that amino acids content of wheat flour and its by-product are found to be in the range between 1.13 and 29.3 g/16 g nitrogen for tryptophan and glutamic acid, respectively, in wheat. And arange between 0.92 to 33.7 g/16 g nitrogen) for tryptophan and glutamic acid, respectively, in patent flour. 2.1.4. Anti-nutritional factors Anti-nutritional factors include enzyme inhibitors, hemagglutinin, flatulence factors, polyphenols, tannins and phytic acid, which inhibit the proteolytic activity of the digestive enzymes such as pepsin and trypsin, which reduced the availability of amino acids (Liener and Katade 1989). 2.1.4.1. Phytic acid Phytate is widely distributed in plants, especially in seeds; with high concentration in mature legumes, cereal grains and oilseeds (Reddy et al., 1982; Oberleas, 1983). The ability of phytic acid to complex with metal is well known and is one of the nutritional concerns; and its derivatives can complex with essential dietary minerals, thus making them unavailable or only partially available for absorption. Phytate thus combines with Ca, Zn, Fe and other divalent metals to form complexes with low solublility (Harland and Harland 1980). Giami et al. (2005) found that the phytic acid content of wheat flour is 18.6 mg/100 g, while Hwrell et al. (2003) showed that the phytic in wheat flour is 0.12%. 2.1.4.2. Tannins Many polyphenolics are colored and are responsible for bran pigmentations (Earp et al., 1983 and Glennie, 1983). Tannins-protein complexes can cause inactivation of digestive enzymes (amylases and possibly lipases and proteases) (Hulse et al., 1980) and reduce protein digestibility by interaction of protein substrate with ionizable iron (Salunkhe et al., 1990). The presence of tannins in food can therefore, lower feed efficiency, depress growth, decrease iron absorption, damage the mucosal linning of the gastrointestinal tract, alter excretion of cations, and increase excretion of proteins and essential amino acids (Reddy and Pierson, 1994). Tannins protect the grain from bird (Bullard et al., 1980), insects (Woodhead et al., 1980) and pre-harvest germination (Harris et al., 1970). De-hulling, and fermentation reduce the tannin content of cereals and other foods (FAO, 1999). 2.2. Watermelon seeds 2.2.1. Botanical features of the plant and distribution Water melon; Citrulus vulgaris, is a member of the family Cucurbitaceae. This crop is widely grown throughout the tropics, subtropics and arid regions of the world, hence there are reports it has been found in the wild state of both sides of Equator (Whitaker and Davis,1962). The watermelon, a vigorous annual, which covers a large area of ground with its sprawling stems, can survive relatively dry conditions because it roots deeply. For this reason, it has become established as an important crop in many developing countries, especially where arid conditions prevail (George,1989). 2.2.2. plant requirements The irrigation will depend on soil type and climate, but because watermelon plants develop a deep and extensive root system applications can be kept to a minimum, but in dry regions sufficient irrigation should be applied prior to sowing to restore the soil to field capacity. In most areas of the world, where watermelons grown for seed production seeds are sown direct into the field in preference to propagation in nurseries and then transplanting (George,1989). 2.2.3. Uses of watermelon seeds The nutritional and oil characteristic of several other seeds of the Cucurbitaceae family has been studied in detail (Das et al., 2002); El-Adawy and Taha,2001); Giami et al. (2005) and Giami and Barber,2004). It has been reported that the fatty acid composition of individual oils is dependent and that the seeds of pumpkin and watermelon can be utilized successfully as sources of good quality edible oil and protein for human consumption (Kamel et al., 1985; and Sawaya et al., 1983). Sawaya et al. (1983) reported that although none of Cucurbitaceae seed oils had been utilized on an industrial scale, many are used as in some countries in Africa and the Middle East. Oyenuga et al. (1975) mentioned that the oil extracted from the watermelon seeds is widely used as a cooking oil and the residual protein fried into protein rich cake known locally as “Igbalo”. It is investigated that a study of its nutritive value and limitations may enhance its use in effectively meeting part of the protein needs. In some parts of Africa, local cultivars with relatively bitter fruits are grown for their seeds, which are roasted and eaten; these are referred to as “egusi”, but production for this purpose is not generally included as part of seed production(George,1989). 2.2.4. Chemical composition of watermelon seeds 2.2.4.1. Moisture content Hassan (1998) reported that the moisture content of watermelon seeds flour as whole seed, kernel and coat was 4.58, 4.22 and 5.92%, respectively. Moreover, Mustafa et al. (1972) found that the moisture content of whole seeds, kernel and hull of the watermelon seeds flour was 4.94, 3.99 and 6.94%, respectively. In Nigeria, Oyenuga et al. (1975) analyzed two varieties of watermelon seeds, which were “Bara” and “Serewe”, and found that the moisture content of raw, un-defatted and defatted Bara was 4.2 and 9.1%, respectively. While fulfatted and defatted Serewe was 3.4 and 8.8%, respectively. However, the moisture content of fried fulfatted and defatted Bara was 3.6 and 9.0%, respectively, and fulfatted and defatted Serewe was 4.0 and 9.2%, respectively. Hassan (1994) determined the moisture content of watermelon seed kernel and coat and found that it was 3.45 and 3.92% ,respectively. 2.2.4.2. Protein content Watermelon seed kernel contains about 38% protein as reported by FAO (1988), which is in agreement with Hassan (1998) who found that the protein content of the watermelon seed was 38.10%for the kernel and 21.3% for the whole seed, but it was 0.64% for the seed coat. Olaofe et al. (1994) mentioned that the watermelon seeds contain high amounts of crude protein (23.7-30.80%), while Oyenuga et al. (1975) found that the protein content of watermelon seeds for two Nigerian varieties (Bara/Serewe) was 35.7 and 30.6%, respectively. Hassan (1994) showed that the protein content of watermelon seeds kernel was about 30.2%, however, for the seed coat was 2.508%. Moreover, Mustafa et al. (1972) reported that the protein content of watermelon seeds for the whole seed, kernel and hull was 18.96, 39.10 and 0.52%, respectively. El-Adawy and Taha. (2001) reported that the seed kernel of watermelon is rich in protein (35.7%), while Asils et al. (1985) determined the protein of watermelon seed and found that it was 16.4 for the whole seed, and 32% for the kernel. 2.2.4.3. Fat content Das et al. (2002) investigated the fat content of watermelon seeds for the whole seed and the kernel and found that it was 28.28% and 4-9.95% respectively, while Hassan (1994) found that the kernel of watermelon seed contained high level of oil (50.36%), but for the seed coat was 2.738%. Mustafa et al. (1972) their analysis for watermelon seeds illustrated that the fat content of whole seed and kernel was 25.87 and 50.64%, respectively, and 0.78% for the hull. Moreover, Oyenuga et al. (1975) found that the oil content of two varieties of watermelon seeds “Bara and Serewe” was 54.2 and 56.9%, respectively. Hassan (1998) reported that the oil content in watermelon seed is noticeably concentrated in the kernel, which is 47.3%, but it was 26.9% for the whole seed, while Asils et al. (1985) determined the oil content of watermelon seed kernel as 51.4%. However, El-Adawy and Taha. (2001) reported that the kernel of watermelon seed was found to be rich in oil (50.10%).

2.2.4.4. Fiber content In 1998, Hassan analyzed watermelon seeds, as whole seed, kernel and seed coat, and reported that the fiber content was 35.0, 1.68 and 74.21%, respectively, while Das et al. (2002) found that the fiber content of watermelon seeds as whole seed and kernel was 32.99 and 1.79%, respectively. Two varieties of watermelon seeds analyzed by Oyenuga et al. (1975) and showed that the crude fiber for the two varieties was 2.4 and 3.1% for the fulfatted samples, but it was 4.6 and 5.2% for the defatted ones. Hassan (1994) reported that the main constituents of the coat were fiber, which was 72.3% and 7.6 in the kernel . Moreover, Asils et al. (1985) found a value of 47.7% fiber for watermelon seed, while Mustafa et al. (1972) mentioned that the fibers content of the watermelon seed was 39.84, 4.17 and 76.13% for the whole seed, kernel and the hull, respectively. 2.2.4.5. Carbohydrates Carbohydrates were determined by Asils et al. (1985) who reported a value of 10.2% in watermelon seed. Moreover, Hassan (1994) found that the kernel of watermelon seed contains low level of carbohydrates (13.26%), however, high in the coat (89.23%). Oyenuga et al. (1975) reported that the percentage of carbohydrates of watermelon seeds are different in un-defatted samples from the defatted ones, which were 3.5% and 8.0%, respectively. Hassan (1998) showed that the carbohydrates of watermelon seeds as whole seed, kernel and seed coat was 10.0, 3.85 and 16.33%, respectively. Mustafa et al. (1972) mentioned that the watermelon seeds contain 8.38, 1.50 and 14.86%, carbohydrates in the whole seed, kernel and hull, respectively, while Das et al (2002) found that the carbohydrate content of watermelon seeds as a whole seed and kernel was 12.76 and 5.53%, respectively. 2.2.4.6. Ash content Ash content of watermelon seeds for the whole seed, kernel and hull was 2.31, 3.03 and 1.57%, respectively, as reported by Mustafa et al (1972), while Hassan (1998) analyzed watermelon seed as whole seed, kernel and seed coat and found that the ash content was3.7, 3.10 and 2.33%, respectively. Asils et al. (1985) reported that the ash content of watermelon seed was 2.6%, while Oyenuga et al.. (1975) analyzed two varieties of watermelon seeds, and found that the total ash content of both varieties was 4.2 and 3.4% for the fulfatted samples, and 9.2 and 8.9% for the defatted ones. Das et al. (2002) found that the ash content of watermelon seeds as whole seed, and kernel was 2.84 and 2.71%, respectively, while Hassan (1994) showed that the ash content of the kernel and coat of the watermelon seeds was 2.7 and 1.6%, respectively 2.2.5. Minerals content Although the minerals exist in minute amounts, their functions are necessary for normal growth and reproduction (Vieira, 1996). Oyenuga et al (1975) reported that the melon seeds are rich in P, Mg, K, Zn, Fe, Mn and Co. It would appear that melon seed would constitute a valuable source of the major elements particularly in diets. For human, in which no special provision is made for the supply of these vital nutrients. Kamel et al. (1985) found that watermelon seeds have significant amounts of Ca, Mg, P and K, however, Hassan (1998) mentioned that the constituents of the ash of the watermelon seeds kernel were found, to some extent, in agreement with those reported earlier by Olaofe et al. (1994) who found that the K was the predominant mineral and Ca, Mg, Na, Mn, Fe and Cu were in moderate high amounts. Hassan (1998) showed that K, Ca, Mg, Na, Mn, Fe and Cu of watermelon seed kernel were 53, 0.68, 28, 105, 0.14, 1.87 and 0.86 mg/kg, respectively, while El-Adawy and Taha. (2001) reported that the watermelon seed flour contains considerable amount of P, K, Mg, Mn and Co. Moreover, Asils et al. (1985) illustrated that the analysis of the ash content of watermelon seed showed significant concentration of calcium, phosphorus, magnesium, and potassium. Copper, zinc and iron ranged between 9-35 ppm. 2.2.6. Amino acids The importance of utilizing oil seed meals as supplementary protein sources for human consumption has received considerable attention in recent years (Hassan, 1998). Hassan (1998) reported that the result of amino acid content he obtained was very low compared to that of the conventional oilseeds. Even though, melon cake is rich in glutamic, aspartic, methionine, therionine, tyrosine and histidine. The amino acid content he reported ranged between 0.06-3.0 g/100 g. El-Adawy and Taha. (2001) reported that paprika seed flour was superior to watermelon and pumpkin seed kernel flours in contents of lysine and total essential amino acids, and the first limiting amino acid is lysine, for both melon and pumpkin seed kernel flours, but it was leucine in paprika seed flour. Giami et al. (2005) illustrated that the nutritional quality (amino acids composition, protein digestibility and protein efficiency ratio) of fluted pumpkin seeds is similar to that of soybean. 2.2.7. Anti-nutritional factors 2.2.7.1. Phytic acid Phytic acid, a substance present in large amounts in most plant seeds, have been shown to lower the bioavailability of minerals in humans and to inhibit the digestibility of plant protein (Lopez et al., 2002). Bineto and Miller,1998 reported that phytic acid complexes with essentially dietary minerals (e.g. calcium, zinc, iron and magnesium) to form phytates and causes the minerals to be unavailable for absorption. Phytic acid has been considered as anti-nutrient because, in large concentrations, it can reduce the bioavailability of minerals. However, in small concentration may also have some beneficial effects; these include slowing the rate of starch digestibility and lowering the blood glucose response, controlling dental caries and cancer and improving the oxygen- providing ability of red blood cells (Kaufman, 1986; Graf, 1985 and Chem, 1986). Hence, methods for reducing to a suitable level the phytic acid in foods, especially protein isolates from oilseeds and legumes, have been the subjects of numerous investigations (Maga, 1982 and Erdman, 1979). Phytic acid is closely associated with the proteins in these plant products and is very often co-isolated with the proteins (Reddy et al., 1982). Graf (1983) reported that phytic acid exhibits a high affinity for Ca+2 over a wide pH range. El-Adway and Taha. (2001) found that the highest level of phytic acid was noticed in pumpkin and melon seed kernel flours, which were 2.27 and 2.63 g/100 g sample, respectively.

2.2.7.2. Tannins Tannins are one of the many types of secondary compounds found in plants (Waniska et al., 2000). The anti-nutritional effects of tannins include diminished growth rate, protein digestibility and feed efficiency in rats, hamsters, swine, poultry and ruminants (Cousins et al., 1981). Hegerman and Putler,1981 found that the larger the protein, the stronger the binding of tannin. But short peptides of two or four amino acids do not bind strongly. El-Adawy and Taha. (2001) observed a significant difference between paprika seed flour and both melon and pumpkin seed kernel flours in tannin content, the highest level of tannins (0.48 g/100 g) for paprika, while it was 0.24 and 0.17 for the melon and pumpkin seed kernel flour, respectively. 2.3. Rheological characteristics When wheat flour is mixed with water, with the required amount of energy, a dough is formed. The behavior of the resulting dough when submitted to mechanical energy input is determined by dough rheological properties (Blocksma,1990). Wheat flour doughs simultaneously exhibit characteristics of viscous liquid and of an elastic solid and hence, are classed as viscoelastic materials. Dough mechanical properties depend on a large variety of factors including, flour cultivar, mixing time, rest period, etc. (Bagley et al. 1998). Campos et al. (1997) tested the rheological behavior of wheat dough and indicated the importance of mixing energy for foaming a developed dough, in agreement with foaming graph tests. Brabender farinograph is an instrument which can read the following:- [1] Water absorption: Which is the amount of water needed to mix with flour to give a dough with a consistency of 500 units. The higher the absorption, the better the yield in the bakery. [2] Dough development time: Which is the time in minutes it takes for the flour to absorb its water and give average consistency of 500 units. The shorter this time, the shorter mixing time will be normally required in the bakery. [3] Dough stability: Which is the length of time in minutes for which the dough maintains the consistency of 500 units. The longer the stability time, the stronger the flour and the more tolerant and intensive it will be to mechanical and other abuse. [4] Resistance: Which is given by the sum of the two latter times. [5] Dough softening: Which is the drop in the consistency below the 500 line as measured at the center of the curve band 12 minutes after the center of the curve band crosses the 500 line. The greater this is, the weaker the flour and the more sensitive the dough to mixing differences. Brabender extensograph is an instrument which can read the resistance of dough to stretching. Weak wheats give low resistance. Also can read the extensibility of the dough and the baking strength of the dough. These two instruments together provide permanent, independent record of dough properties and enable one to classify and define wheats and flours according to their dough properties and assess their suitability for baking (Williams, 1970). El-Adawy (1995) reported that the water absorption, development time and dough weakening were increased in all blends of red wheat flour and sesame products, however, dough stability decreased. Sadowska et al. (2003) found that at the comparable level of supplementation, the rheological properties of dough were found to be either very good, for up to 12.5% addition of 2-day germinated pea flour. Lupin and soya flour, at 5 and 10% substitution levels of wheat flour, increased the stability and the tolerance index of the dough, this was reported by Doxastakis et al. (2002). Yassen et al. (1991) added whole and defatted tomato seeds meal at 5, 10 and 15% wheat flour replacement levels, and found that the water- absorption dough development time and dough stability were improved by increasing the level of supplementation. De-fatted tomato seed meal decreased the mixing tolerance index and the dough weakening, compared with those of whole meal. Extensigraph results indicated that dough extensibility, resistance to extension, and dough energy were minimized with increasing tomato seed meal in the formula containing wheat flour. 2.4. Composite flour Cereals are an important source of energy and protein in the human diet. Although carbohydrates are their main dietary contribution, they also provide proteins and smaller amounts of lipids, fiber and vitamins (Waliszewski et al., 2000). It is commonly known that the main nutritional drawback to cereals, particularly corn, is their low protein content and the limited biological quality of their proteins (high deficiency in lysine and tryptophan) (Ortega et al., 1986), when compared with proteins found in animals. Nevertheless, the protein quality found in a given cereal can be improved by combining it with the high quality sources of protein (Martinez-Floers et al., 2005). Oilseed pastes have good prospects for use in human nutrition, as they contain a high percentage of proteins as reported by Figueroa et al. (2003). And have a good profile of essential amino acids as reported by Serna- Saldivar et al. (1988). Composite flour technology initially confined to the process of mixing wheat flour with cereal and legume flours for making bread and biscuits, however, the term can also be used in regard to mixing of non-wheat flours; roots and tubers, legumes or other raw materials (Dendy, 1992). In Africa, there has been an ever-increasing demand for wheat products such as bread. Africa is not a major wheat-growing region, but it produces large quantities of other cereals such as sorghum and millets. Thus composite flour technology holds excellent promise for developing countries. Although actual consumer trials have been rare, products made with composite flour have been well accepted in Colombia, Kenya, Srilank, and the Sudan (Dendy, 1992). Cookies have been made suggested as better use of composite flour than bread, because of their ready-to-eat form, wide consumption and relatively long shelf-life (Tsen et al., 1973 and Lorens et al., 1979). Efforts have been made to promote the use of composite flours in which flour from locally grown high protein oilseeds and legumes replace a portion of wheat flour for production of high protein composite bakery products (United Nations Economic Commission for Africa, (UNECA, 1985). In Sudan, like most African countries south of Sahara, it is confronted by rapidly growing problems of satisfying the ever-increasing demand for wheat and its products such as bread. In order to make composite flour program possible, it is necessary that the milling industry be promoted to produce high quality flour from non-wheat materials in sufficient quantities (Idow, 1989). Samuel and Chattopadhyay (1989) reported that protein enriched snacks from combinations for improved defatted soybean, maize, rice flour was formulated. Organoleptic evaluation of the snack showed that the product was acceptable. In many developing countries, besides experiments with bread making using locally produced cereal flours or other starchy products, national programs have been concerned with manufacturing biscuits supplemented with minerals, vitamins, dairy products and proteins for feeding children and adolescents (Albert, 1990). Tsen et al. (1973) showed that fortifying wheat flour with full-fat soy flour in making bread can raise protein content, balance essential amino acids, and increase bread’s caloric value. Cookies with high sensory ratings have been produced from blends of wheat/cowpea (Okaka and Iseih, 1990; McWatters et al., 2003), soybean kinema and wheat (Shrestha and Noomhorm, 2002), wheat/chickpea (Singh et al., 1991) or wheat/safflower (Ordorica-Falomir and Paredes-Lopez, 1991). 2.5. Biscuit making Biscuits are widely accepted and consumed in many developing countries (Giami et al., 2004). The word biscuit comes from the French word biscuit, which means twice cooked (Herbsat, 1995). Biscuit in general language thin flour, which has been baked in the oven until highly dried (every body cyclopeodia, 1912). 2.5.1. Biscuit ingredients Flour, the quality of wheat is usually judged by its suitability for particular end use (Zeleny, 1971). As mentioned previously, soft wheats are used for biscuit and cakes (Vieira, 1996). Gallagher (1984) reported the range of 8 to 10% protein is often ideal for the production of biscuit flour. For the European biscuits (cookies) the maximum protein content is 9.5% (Harrell, 1959). The sweetener is very important to the cookie formula. No cookie formula is without some forms of sweeteners. The quality of sweeteners added is usually such that it has significant effects on the texture and appearance of the product as well as on the flavor (Matz, 1968). Granulated,fine granulated, or powdered sweetener can be used alone or in combination to adjust spread and machining properties (Matz, 1968). Sucrose is a non-reducing disaccharide, which upon hydrolysis, yields two molecules of reducing sugars, one of glucose and one of fructose (Kulp, 1994). Sugars in large amounts tend to make the dough more sticky (Matz, 1968). Water, recognized as a toughener. It is necessary to moisten the flour protein to form gluten structure. Also during heating promotes the gelatinization of starch. Water can dissolve certain constituents, such as sugars, salts and baking powder. Water, also contributes to dough consistency and helps to control the temperature of the dough or (Bennion, 1980; Stevenson and Miller, 1960 and Kordylas, 1991). On the whole it appears that changing the water content is a poor method for controlling spread, though it does affect highest (Matz, 1968). Fats and oils have been known as important baking ingredients for centuries (Bennion, 1980). The type and the amount of shortening and emulsifiers in the formula affect both machining response of the dough and the quality of the finished product (Matz, 1968). Shortening has four primary functions in cookies, lubrication, aeration, eating quality and spread (Kulp, 1994). Addition of milk helps the product to be brown during baking, also adds nutritive value to the product (Kordylas, 1991). Also Matz (1968) reported that in baked goods, milk and milk derivatives are used for color improvement, water absorbing and spread control properties and flavor. In cookie and crackers casein, which is one of the principal proteins of milk assists in forming porous structure and is regarded as a toughener. Leavening agents and flour mixtures are leavened to make product that is light and porous. This has been done by the incorporation or formation, in the product, of gas that expands during preparation and subsequent heating. Bennion (1980) and Kordylas (1991) reported that there are three leavening agents, air, which is incorporated into flour mixture by sifting, creaming shortening or fat, beating eggs or beating the mixture itself, water- vapor, which is formed in quantity sufficient to leaven a mixture, when liquid and flour are present in equal volume, and carbon dioxide, which its source is either sodium bicarbonate or ammonium bicarbonate although acetone dicarboxylic acid has been suggested and perhaps used. 2.5.2. Kneading and forming of biscuits Kneading is a process of stretching and folding dough. Kneading is most usually done by hand, but if a large quantity is being produced it can be a string task and a powdered kneader may be preferred (Fellows and Hampton, 1992). The rolling and kneading results with flakiness biscuit not sticky and has sufficiently developed gluten (Phillips, 2003). After kneading, the dough has to be formed into the desired shape (Fellows and Hampton, 1992). Phillips (2003) reported that the biscuit dough is cut into shapes usually round with biscuit cutter, about 2-3 inches in a diameter. 2.5.3. Baking Baking is heating or cooking by the hot air, and also by oven floor and trays. The cooking temperature for most ovens ranges from 120 to 260°C (250-500°F) (Kordylas, 1991). Stevenson and Miller (1960) reported that, tin or aluminum is better suited for baking muffins and biscuits than are iron or glass. Also round pans give more browning than pans with square corners. Temperature and time of baking also affect the quality of finished baked products (Stevenson and Miller, 1960). 2.6. Biscuit of composite flour Gonzalez et al. (1988) reported that biscuits could be made from wheat flour, rice flour and soybean flour. Sugar-snap biscuits were enriched with sunflower protein isolate. Sensory evaluation scores showed acceptable biscuit quality at up to 15% sunflower protein isolate (Claughton and Pearce, 1989). The utilization of milk proteins, vegetable proteins and fish proteins to improve the nutritive value of biscuit products was practiced (Rajor and Thompkinson, 1989). Mueses et al. (1993) fortified biscuits with pigeon pea flour up to 100% Level and found it unacceptable, but those with 75% wheat flour and 25% pigeon pea flour had acceptable appearance and taste. Shrestha et al. (2002) supplemented biscuits with soy and kinema flours. Kinema supplementation resulted in decreased hardness but increased weight and spread ratio in fortified biscuits. Evaluation of sensory characteristics showed greater acceptance of kinema-supplemented biscuits in comparison with full-fat soy flour-supplemented biscuits. Cookies (soft type biscuits) were produced from blends of wheat flour containing graded levels (0-25%) of protein concentrates prepared from ungerminated and germinated fluted pumpkin seeds. The use of up to 15% concentrate from ungerminated seeds in the blends produced cookies with spread ratio, hardness, color and flavor, similar to the 100% wheat flour (control) cookies. Cookies supplemented with concentrates from germinated seeds at 15-25% levels were nutritionally comparable to diets based on casein, but at the expense of acceptability (Giami and Barber, 2004). Giami et al. (2005) fortified cookies with fluted pumpkin seed flour (FPF). Up to 15% substitution of wheat flour (WHF) with (FPF) produced acceptable cookies with spread ratio, hardness, color and flavor similar to the control (100% WHF) cookies. Use of higher levels (20-25%), however, resulted in in these quality attributes. CHAPTER THREE MATERIALS AND METHODS 3.1. Materials Patent flour, 72% extraction, from a mixture of Australian and American wheats, obtained from Wadi-Elmoulouk Mill-6th October City, Cairo, ARE. A quantity of 4 kg watermelon seeds was bought from the local market “Souq Bahri”. Alaseel (hydrogenated vegetable oils), skimmed milk, sugar: from the local market. All chemicals used were of analytical grade. 3.2. Methods 3.2.1. Sample preparation The sample of watermelon seeds was prepared according to the AOAC (1990) method. The seeds were cleaned from dust, broken seeds and impurities, to prepare for further chemical analysis. Before starting laboratory analysis, any foreign particles were removed from the samples. Then the sample was ground using Braun grinder to the fine powder of the sample for analysis. The prepared samples were kept in polyethylene bags for analysis at ambient temperature. 3.2.2. Proximate analysis The determination of moisture, crude fiber, crude fat and ash contents were carried out on the samples according to AOAC (1984) method, and carbohydrates were obtained by difference.

Plate (1) watermelon seeds

Plate (2) - wheat flour - watermelon seeds flour

3.2.2.1. Determination of moisture content Two grams of well-mixed samples were weighed accurately in clean preheated moisture dish at known weight by using sensitive balance. The uncovered sample and dish were kept in an oven provided with a fan at 105°C and left to stay 4 hours. The dish was covered and transferred to a desicator and weighed after reaching room temperature. The dish was heated in the oven for another two hours and was reweighed. This was repeated until constant weight was obtained. The loss of weight was calculated as percent of sample weight and expressed as moisture content:

Moisture content (%) = ( wt1 – wt2 ) x 100 Sample wt. Where:

wt1 = weight of sample + dish before oven dry.

wt2 = weight of sample + dish after oven dry. 3.2.2.2. Determination of ash A crucible was weighed empty, and then accurately two grams of sample were put in it. The contents were ignited in a muffle furnace at 550°C for 3 hours or more until white gray or reddish ash was obtained, then the crucible was removed from furnace and placed in a desicator to cool then weighed. The process was repeated until constant weight was obtained. Ash content was calculated using the following equation

Ash content (%) = ( wt1 – wt2) x 100 Sample wt. Where:

wt1 = weight of crucible with ash.

wt2 = weight of empty crucible. 3.2.2.3. Determination of crude protein Nitrogen content determinations were made on the samples by micro-Kjeldahl technique following the method of AOAC (1975). About 0.2 gm of sample was weighed accurately into micro-Kjeldahl flask, 0.4 gm of catalyst mixture (90% potassium sulphate and 10% cupric sulphate) and 3.5 ml of concentrated sulphuric acid were added, the flask was placed in the digestion equipment for 3 hours. The sample placed in the distillation apparatus; 20 ml of 40% NaOH were added. The ammonia evolved was received in 10 ml of 20% boric acid solution. The trapped ammonia is titrated against 0.02 ml HCl using universal indicator (methyl red + bromo cresol green).

Nitrogen content % = TV x N X 14.00 x 100 1000 wt. of sample Protein content % = (Nitrogen content %) x nitrogen factor Where: TV = Actual volume of Hcl used for titration (ml Hcl-ml blank) N = Normality of Hcl 14.00 = Each ml of Hcl is equivalent to 14 mg nitrogen. 1000 = to convert from mg to g. 3.2.2.4. Determination of fat (ether extraction) A dry empty extraction flask was weighed, about 2 grams of sample was weighed and placed in a filter paper, then placed in extraction thimble free from fat and covered with cotton wool. The thimble was placed in an extractor. Extraction was carried out for 7 hours with petroleum spirit (60- 80°C B.F), after that the apparatus was carefully dismantled and the solvent was evaporated to dryness in an air-oven. The flask with extracted oil was cooled and weighed. The total oil content was calculated as follows:

Fat content (%) = (wt2 – wt1 ) x 100 Sample wt. Where:

wt1 = weight of empty extraction flask.

wt2 = weight of extraction flask with oil. 3.2.2.5. Determination of crude fiber Two grams of an air dried fat-free sample were transferred to dry 600 ml beaker. The sample was digested with 200 ml of 1.25% (0.26N) H2SO4 for 30 minutes, and the beaker was periodically swirled. The contents were removed and filtered through buchner funnel, and washed with water. The digestion was repeated using 200 ml of 1.25% (0.23N) NaOH for 30 minutes, and treated similarly as above. After the last washing the residue was transferred to ashing dish, and dried in an oven at 105°C overnight, then cooled and weighed. The dried residue was ignited in a muffle-furnace at 550°C to a constant weight, and allowed to cool, re-weighed, and then the fiber percentage was calculated as follows:

Crude fiber content (%) = ( wt1 – wt2) x 100 Sample wt. Where:

wt1 = weight of sample and crucible.

wt2 = weight of crucible with ashed sample. 3.2.2.6. Determination of carbohydrates The total carbohydrates were calculated by difference, the sum of ash, moisture, crude protein and oil contents, were subtracted out of 100 to obtain this figure (Pearson, 1976).

3.2.3. Determination of minerals content Minerals of samples were extracted according to Pearson’s (1976) method. Each sample was burnt in a muffle furnace at 550°C. Each sample was placed in a sand bath for 10-15 minutes after addition of 5 ml of 5N HCl. Then the solution was carefully filtered in a 100 ml volumetric flask and finally distilled water was added to make up to mark. The extracts were stored in bottles for further analysis. From the extract obtained in the previous, seven elements were determined. The elements zinc, calcium, manganese, potassium, magnesium, sodium and iron were determined by Perkin-Elmer 2380 atomic absorption spectrophotometer. 3.2.4. Determination of anti-nutritional factors 3.2.4.1. Determination of tannins content Tannin content of wheat and watermelon seeds was estimated using modified vanillin-Hcl in methanol methods described by Price and Butler, (1978). About 0.2 g of the ground sample was placed in a 100 ml conical flask. 10 milliliters of 1% Hcl in methanol (v/v) were added, shaken for 20 minutes. And centrifuged at 2500 rpm for 5 min. One milliliter of supernatant was pipetted into a test tube and 5 ml of vanillin-Hcl reagent were added. The optical density was read using a colorimetric Lab System Analyzer-g filters,( J. Mitra and Bros. Pvt. Ltd.) at 500 nm after 20 minutes incubation at 30°C. A standard curve was prepared expressing the results as catechin equivalents, i.e. amount of catechin (mg/ml), which gives a color intensity equivalent to that given by tannins after correcting for blank. Calculation Tannin concentration was expressed as catechin equivalent (C.E) as follows: C.E (%) = C x 10 x 100 200 Where: C = Concentration corresponding to the optical density. 10 = Volume of extract in ml 200 = Sample weight in mg. 3.2.4.2. Phytic acid content Phytic acid content was determined by the method described by Wheeler and Ferrel (1971). Two grams of dried sample were weighed in 125 ml conical flask. The sample was extracted with 50 ml of 3% trichloro acetic acid (TCA) for 3 hours with mechanical shaking. The supernatant was transferred to a 40 ml tube and 4 ml of Fecl3 (Fecl3 solution containing 2 mg Fe+3 ion 1 ml 3% TCA) were then added to the aliquot. The tube was heated in a boiling water bath for 45 min. One or two drops of 3% sodium sulfate dissolved in 3% TCA were added. The tube was cooled and centrifuged for 10-15 min and the clear supernatant was decanted. The precipitate was washed twice by dispersing well in 25 ml 3% TCA, heated for 10-15 min. in a boiling water bath and then centrifuged again. Washing was repeated once more with distilled water enriched with 3 ml of 1.5N NaOH, and the volume completed to approximately 30 ml with distilled water. Heated in boiling water bath for 30 min. and hot filtered using Whatman No. 2. The precipitate was washed with 60-70 ml hot water, and the washings were decanted. The precipitate from the filter paper was dissolved in 40 ml hot water 3.2N

HNO3 and placed in 100 ml volumetric flask. The paper was washed with hot distilled water and the washing was collected in the same flask then completed to volume. A 0.5 ml of aliquot was taken from the above solution and transferred into 10 ml volumetric flask. Then 2 ml of 1.5N KSCN were added and completed to volume by water then immediately (within one min.) read at 480 nm using (SP6 RY Unicam) spectrophotometer.

A standard curve of different Fe (NO3)3 concentrations was plotted to calculate the ferric ion concentration. The phytate phosphorous was calculated from the iron concentration assuming 4:6 iron to phosphorous molar ratio. The phytate (mg/100g) =

6 /4 x A x mean K x 20 x 10 x 50 x 100 mg /100 g 1000 x 2 Where A = Optical density. 3.2.5. Determination of amino acids content A sample corresponding to 40 mg protein was weighed into a 25×150 mm hydrolysis tube. Aliquot (7.5 ml) of 6.0 N HCl was added purged with nitrogen for 60 second, and tube was capped immediately. The tube was placed in 110ºC oven for 24 hrs. removed from the oven and was allowed to cool. The tube contents were quantitatively transferred to 25 ml volumetric flask and completed to volume with HPLC grade water. About 1 ml of the solution was filtered through 0.45 um sample filter. Amino Acid Derivatization Ten microlitres of the filtered sample in 6×50 mm tube was placed into drying vessel and dry in waters pico-tag work station in 10-15 minute at<50 millitorn. Aliquot (30 ul) of redry solution (200 ul methanol, 200 ul 0.2 N Sodium acetate and 100 ul triethylamine) and dry the sample again in the work station . Aliquot (30 ul) of the freshly prepared of the derivatization, 50 ul triethylamine and 50 ul phenylisothiocyanate, PITC) to the contents and allowed to react for 20 minutes and dry in the work station for 15 minutes, 30 ul HPLC grade methanol was added and redried. Then 100 ul of sample diluent were added to the tube, vortexed and transferred to injection vials. The standard amino acid solution was treated the same manner as the sample. Amino Acids Profile The apparatus used is spectraphysics analytical, Inc. AOO 99-600 with spectra Focus Optical Scanning detector and spectra system UV 2000 detector and Ultrasphere C18 Beckman Column. The analysis was carried out using a gradient of Pico-Tag solvent A and B at 40°C and flow rate 1ml/min. Detection of the separated Pico-Tag amino acids was at 524 nm wave length. Before injecting the sample, the illustrated HPLC was calibrated by two injections of standards.

3.2.6. Rheological properties of dough The rheological properties of the dough prepared from wheat flour and its blends with watermelon seeds flours in the ratio of 100:0, 95:5, 90:10, 85:15% wheat flour to watermelon seeds flour were determined using the Brabender Farinograph and the Extensograph methods of AACC (1983). 3.2.6.1. Farinograph characteristics 3.2.6.1.1. The titration curve Titration curve was used for the assessment of the water absorption for each flour sample. A sample of 300 g flour was weighed and transferred into clean farinograph mixer. The farinograph was switched on 63 rpm for one min, then the distilled water was added from special burette (any deviations from the 500 units consistency, correspond to water absorption which must be corrected, using 20 units deviation correspond to 0.5% water (whenever consistency was higher than 500 F.U. more water was needed and vice-versa). When the consistency was constant, the instrument was switched off and the water drawn from the burette indicates water absorption of the flour (water used for preparing the dough). 3.2.6.1.2. The standard curve The measuring mixture was thoroughly cleaned. A sample of 300 g was weighed, and then introduced into the mixture; farinograph was witched on as above. The water quantity, which was determined by the titration curve, was fed at once. When an appreciable drop on the curve was noticed, the instrument was run for further 12 min, and then shut-off. The significant readings taken from a farinograph are:- 1-The water absorption: The ability of the flour to absorb water and prescribes the quantity of water, which has to be added to the flour during bread production. 2-Arrival time: The difference between zero and the point at which the top of the curve first intersect the 500 F.U. line. 3-Departure time: The difference between zero to the point where the top of the curve leaves the 500 F.U. line. 4-Dough stability: The difference between the time where curve first intercept (arrival time) and leaves (the departure time) the 500 F.U. consistency line. 5-The softening of the dough: The difference between the dough strength between the moment dough weakening begins and after 12 minutes dough kneading in F.U

3.2.6.2. Extensigraph characteristics A dough sample was prepared from flour, water and salt with farinograph described before. Two pieces of 150 g from the dough were separated. The dough pieces were shaped to a ball, and then the two pieces were put in a dough holder then put into fermentation cabinet. After 45 minutes, both dough pieces were tested one by one. For this purpose, the dough holder with the dough was put onto a balance system. A hook was pulled through the dough piece at a constant speed, which was thus stretched until it breaks. By means of the balance system, the load acting onto the dough during this procedure was measured and recorded. The resulting diagram (the extensogram) showed the force, which the dough opposes to the stretching force as a function of the stretching time, i.e. the stretching length. Then the dough was put back again into fermentation cabinet for another resting time. The dough pieces were tested again after 90 and 135 minutes. The most common measurements made on load-extension charts or extensogram were:- 1-Resistance to extension: Height of diagram after 5cm of diagram length. 2-Extensibility: Length of curve in cm. 3-Energy: Area covered by the curve, measured by the planimeter. 3.2.7. Preparation of biscuits Biscuits were prepared according to the modified method reported by Abdallah (2003). Biscuit formulation is shown in the table below:

Ingredients Quantity (g) Flour 100 Sugar( powder) 30 Shortening 20 Skim milk powder 2 Sodium chloride 1 Sodium bicarbonate 0.3 Ammonium bicarbonate 1.5 Glucose 2 Water 25 L-cysteine 0.015

Procedure Two hundred grams of flour were weighed; sugar powder, shortening, skim milk powder and glucose were creamed in Horbart N-50 mixer with a flat beater for 8 min. Salt, ammonium bicarbonate, sodium bicarbonate and cysteine were dissolved separately in part of the required water and added to the . Mixing was done for 3 min. till homogenous cream was formed. Finally, flour sieved twice was added and mixed for 1 min. The dough was sheeted to a thickness of 0.235 mm with the help of two ruler placed at two sides of the dough. The sheeted dough was cut into round shape using 4.985 mm. Diagram cutter. The cut dough was transferred to an aluminum tray. The biscuits were baked in electric oven maintained at 170°C for 10 min. The baked biscuits were cooled for about 20 min, packed in plastic bags and stored at room temperature.

3.2.7.1. Method Biscuits were made from wheat and watermelon seeds composite flours, they were mixed in the ratio 100/0, 95/5, 90/10 and 85/15 respectively. The test sheet for sensory evaluation was shown in Fig. I. 3.2.7.2. Sensory evaluation of biscuits Evaluation of biscuits made from wheat and watermelon seeds composite flour for various sensory characteristics was carried out. Ten judges were asked to evaluate the biscuit samples fresh. Fig. I represents the sheet for panel test. 3.2.8. Statistical analysis According to Mead and Gurnow (1983), data generated was subjected to Statistical Package for Social Sciences (SPSS), means (±SD) were tested using one factor analysis of variance (ANOVA), and then separated using Duncan’s Multiple Range Test (DMRT).

Figure (1) PANEL TEST FOR BISCUIT SAMPLES (Hedonic) Please examine the following samples of biscuits presented in front of you, and give values to attributes shown below, using Table (2) to help you. 10-8: Excellent. 6-7: Very good. 4-5.9: Good. 2-3.9: Fair. 1-2.9: Poor. Table (1) Sample Color Odor Surface Taste Mouth Texture Total No. (10) (10) feel(10) (10) feel (10) (10) score (60) A B C D

Table (2)

Quality Color Odor Surface Taste Mouth feel Texture Description feel Golden Brown Desirable Pleasant Easy break down. Desirable Uniformity Normal Smooth Normal Crispy Hard Brownish Residual Taste Undesirable Off flavor Rough Off Taste

Whitish Formation of Brittle

dough lump in Non Uniform mouth Grittiness

CHAPTER FOUR RESULTS AND DISCUSSION

4.1. Chemical composition of wheat and watermelon seed flours The chemical composition of wheat flour (72% extraction rate) and watermelon seed flour is shown in table (1). The results are expressed on dry matter basis per 100 g of material. 4.1.1. Moisture content Wheat flour gave higher value of moisture content (10.04%), while watermelon seeds flour gave 5.09%, as shown in table (1). The moisture content of wheat flour was lower than the range of 13.0-15.5% for wheat flour (extraction 72%), reported by Kent-Jones and Amos (1967), and higher than four Sudanese wheat cultivars namely; Condor, Sasaraib, Elneilain and Deberia reported by Mohammed (2000). The result obtained was in agreement with 10.5% for wheat, (plain, all purpose) reported by Giami et al. (2005). The moisture content of watermelon seeds flour which is (5.09) was between 4.94% for whole seeds, and 5.3% which was reported by Mustafa et al. (1972), and Dmafuvbe et al. (2004), respectively, but higher than the range of 3.4 to 4.2% reported by Oyenuga et al. (1975). This value was lower than the moisture content of whole seeds watermelon, 5.92% reported by Hassan (1998). 4.1.2. Ash content Table (1) shows the ash content of wheat and watermelon seeds flours. Results showed that wheat flour contains 0.507% ash content, which is lower than watermelon seeds flour (2.97%).The result obtained was in agreement with the range of 0.3 to 0.6% reported by Kent-Jones and Amos (1967), and agreed within the range of 0.38-0.84% of Sudanese wheat flour, reported by Badi et al. (1976). The ash content of watermelon seeds flour (2.97%) was in the range of 1.57-3.03%, reported by Mustafa et al. (1972), and agreed with 2.84% for whole seeds, reported by Das et al. (2002), but higher than 1.57% for the hull, reported by Mustafa et al. (1972). 4.1.3. Protein content The protein content for watermelon seeds flour was higher (20.61%) than for the wheat flour (11.05%), with highly significant difference at level (P>0.05) as shown in table (1). The protein content of wheat flour is comparable to the range of 8- 13% for wheat flour (extraction 72%), reported by Kent-Jones and Amos (1967), and agreed with 11% for white flour, reported by Vieira (1996) and with 11.5%as found by Giami et al. (2005). But it was lower than 13% for the whole wheat, calculated by Vieira (1996). The protein content of watermelon seeds flour (20.61%) was in agreement with 21.3% for the whole seed, reported by Hassan (1998), but higher than 18.96% and 16.4%, which were found by Mustafa et al. (1972) and Asils et al. (1985), respectively. This value of protein content for watermelon seeds flour was lower than the range of 23.7-30.80% reported by Olaofe et al. (1994), and lower than 35.71% calculated by El-Adawy and Taha. (2001).The difference could be due to location or varietals differences. 4.1.4. Fat content The fat content for wheat and watermelon seed flours were 1.43 and 30.5%, respectively, as shown in table (1). The value of fat for watermelon seeds flour was higher than for the wheat flour, and this is due to the classification of watermelon seed as oilseed, as reported by Omafuvbe et al. (2004). The fat content of wheat flour was within the range of 1-2% reported by Pyler (1973) and 0.8-1.5% found by Kent-Jones and Amos (1967), but lower than the range of 2.15-2.35% for four Sudanese cultivars (Deberia, Elneilain, Condor and Sasaraib), reported by Mohammed (2000). The fat content of watermelon seeds flour (30.50%) was higher than 28.28, 25.87 and 26.9% reported by Das et al. (2002); Mustafa et al. (1972) and Hassan (1982), respectively. But lower than the results reported by Oyenuga et al. (1975); El-Adawy et al. (2001) and Omafuvbe et al. (2004),which were 54.2,50.1and 37.5%,respectively. 2.1.5. Fiber content Wheat gave lower value of fiber content 0.150%, while watermelon seeds flour gave 33.523% as shown in table (1). The fiber content of wheat flour agreed with 0.2% for the wheat flour (72% extraction), which was reported by Kent-Jones and Amos (1967). But lower than the range of 2.10- 2.85% for four Sudanese cultivars reported by Mohammed (2000). The value of fiber content of watermelon seeds flour which is 33.523% was in agreement with 35.0% reported by Hassan (1998) and 32.99% for the whole seed, found by Das et al. (2002). This value disagreed with those reported by Omafuvbe et al. (2004); Asils et al. (1985) and Oyenuga etal. (1975), which were 15.8, 47.7and2.4%, respectively. 4.1.6. Carbohydrates The calculated carbohydrate (by difference) for wheat flour was 76.79%, higher than watermelon seeds flour 7.307% as shown in table (1). The result of carbohydrate for wheat flour was higher than the range of 65- 70% reported by Kent-Jones and Amos (1967), and 75.9 and 72.5%, which were found by Giami et al. (2005) and Doxastakis et al. (2002), respectively. The carbohydrate of watermelon seeds flour which is 7.307% was lower than the ranges reported by Asils et al. (1985); Hassan (1998) and Das et al. (2002), which were 10.2, 10 and 12.76%, respectively, but close to 8.38% for whole seed, found by Mustafa et al. (1972).

Table (1): Chemical composition of watermelon seeds and wheat flours

Treatment Moisture (%) Ash (%) Protein (%) Oil (%) Fiber (%) CHO (%)

Watermelon 5.09(±0.03)b 2.970(±0.06)a 20.61(±0.36)a 30.50(±0.36)a 33.523(±0.46)a 7.307(±0.13)a seeds flour

Wheat flour 10.04(±0.05)a 0.507(±0.09)b 11.05(±0.10)b 1.43(±0.15)b 0.150(±0.01)b 76.793(±0.54)b

Mean values (±SD) having different superscript letters in columns differ significantly (P≤0.05). W.F=Wheat flour. M.F=Watermelon seed flour. 4.2. Minerals content Table (2) presents the results of the mineral composition of wheat flour and watermelon seed flour. There was a highly significant (P≤0.05) difference observed between wheat and watermelon seeds flours in their contents of minerals. The higher level of minerals observed in watermelon seed flour except Mg, which were 42.09, 18.86, 33.358, 232.41, 3.42, 1.47 and 3.22 mg/100 g for Ca, K, Na, Mg Fe, Mn and Zn, respectively. Generally, these results were in good agreement with those reported by Kamel et al. (1985) and Oyenuga et al. (1975) who found that the melon seed flour is rich in Mg, K, Zn, Fe and Mn. While the lower level of minerals noticed in wheat flour, which were 20.24, 7.25, 3.44, 270.55, 0.82, 0.75 and 0.85 mg/100 g for Ca, K, Na, Mg, Fe, Mn and Zn, respectively. These results were higher than the minerals content of commercial wheat flour, which was analyzed by Pyler (1973). 4.3. Anti-nutritional factors The anti-nutritional factors of wheat flour and watermelon seed flour are illustrated in table (3). 4.3.1. Phytic acid content There was a highly significant (P≤0.05) difference between wheat and watermelon seed flours in their contents of phytic acid. Higher level of phytic acid was noticed in watermelon seeds flour (1445.33 mg/100 g), this result was lower than (2630mg/100g) which was reported by El- Adawy and Taha (2001). While the lower phytic acid content was found in wheat flour (126.00 mg/100 g). This result agreed with that reported by Hwrell et al. (2003) (120.00 mg/100 g) and higher than that found by Giami et al. (2005) (18.6 mg/100 g).

Table (2): Minerals in wheat flour and watermelon seeds

Flour Ca (mg/100g) K Na Mg Fe (mg/100g) Mn Zn (mg/100g) (mg/100g) (mg/100g) (mg/100g) (mg/100g)

W.F 20.24(±0.01)b 7.25(±0.10)b 3.44(±0.01)b 270.55(±0.01)a 0.82(±0.43)b 0.75(±0.01)b 0.85(±0.01)b

M.F 42.09(±0.01)a 18.86(±0.10)a 33.58(±0.01)a 232.41(±0.01)b 3.42(±0.01)a 1.47(±0.01)a 3.22(±0.01)a

Mean values (±SD) having different superscript letters in columns differ significantly (P≤0.05) W.F = Wheat flour. M.F = Watermelon seeds flour. 4.3.2. Tannins content There was no significant (P≤0.05) difference observed between wheat and watermelon seeds flours in their contents of tannins. Wheat flour gave a value of 15.0 mg/100 g, while melon seed flour gave a value of 16.7 mg/100 g, which was lower than that reported by El-Adawy and Taha (2001) (240 mg/100 g). 4.4. Amino acid content Amino acids content of watermelon seeds flour are shown in table (4). A significant correlation between grain protein percentage and amino acid values has been reported (Acouistucci et al. (1995). The amino acid profiles of watermelon and pumpkin seed kernel flours were similar or only slightly different (El-Adawy and Taha, 2001). From table (4), the watermelon seed flour was higher in glutamic, arginine and aspartic acid (3.41,2.6 and 1.64%,respectively). But it was lower in cystine, methionine and lysine (0.27,0.54 and 0.55%,respectively), which agreed with that reported by El-Adawy and Taha (2001), and Oyenuga et al. (1975).These results were in agreement with that reported by Oyenuga et al. (1975) who reported that the protein of the watermelon seeds will complement only with protein sources that are low in trypotophan, but adequate in lysine and methionine, the amino acids in which the melon seed meal is deficient. It is not likely to be a good supplement to cereals, which also have lysine as their most limiting amino acid and legumes, which have the sulphur amino acids as their major limitation.

Table (3): Tannins and phytic acid in wheat flour and watermelon seeds

Flour Tannins Phytic acid (mg/100g) (mg/100g)

W.F 15.0(±0.00)a 126.00(±1.00)b

M.F 16.7(±0.29)a 1445.33(±105.2)a

Mean values (±SD) having different superscript letters in columns differ significantly (P≤0.05). W.F = Wheat flour. M.F = Watermelon seeds flour.

Table (4): Amino acids profile of watermelon seeds flour and wheat flour.

Amino Watermelon seeds Wheat flour(from acids(%of flour literature) protein) Aspartic 1.64 3.90 Therionine 0.63 2.64 Serine 0.93 5.40 Glutamic 3.41 33.7 Proline 0.64 11.69 Glycine 0.97 2.96 Alanine 0.86 2.67 Cystiene 0.27 1.76 Valine 0.82 4.32 Methionine 0.54 1.73 Isoleucine 0.66 3.91 Leucine 1.22 6.63 Phenylalanine 0.91 4.77 Histidine 0.42 1.29 Lysine 0.55 1.97 Argenine 2.60 3.73

4.5. Rheological characteristics The rheological properties of wheat flour and watermelon seeds flour blends are shown in tables (5 and 6). 4.5.1. Farinograph characteriscts The farinograph characteristics of wheat flour with watermelon seed flour are presented in table (5) and Fig. (2,3, 4 and 5). The water absorption of wheat flour was 61.8% and the dough development time was 1.5 minutes. Dough stability was 1.1 minutes, degree of softening 10 minutes after begin was 66 FU but 12 minutes after maximum was 83 FU were observed. All these values indicated relatively weak dough of wheat flour. The results showed a decrease in water absorption with the addition of 5,10 and 15% watermelon seeds flour from61.1 to 59.9%. Dough development time showed decrease with increasing watermelon seeds flour but the highest drop in dough development time was observed when 10% watermelon seeds flour was added,, but at 15% increased again. With the addition of 5% watermelon seeds flour, the stability decreased from 1.1 to 0.7 minutes, and the addition of 10% increased it to 6 minutes, but it decreased again to 4.2 minutes with the addition of 15%. Softening (12 minute after maximum) at 5% addition showed similar result to the wheat flour (control), which was 83 FU. The softening decreased with the addition of 10% to 67 FU, but slight drop was observed with the addition of 15% to 75 FU. The increment of softening in the wheat flour (control) indicating weakening of dough as reported by Williams (1970).

Table (5): Farinogram readings of wheat flour with watermelon seed flour.

Water absorption Dough development Dough Degree of Degree of Flour blends* (%) time stability softening after10 softening after 12 (min) (min) min (FU) min ( FU) Control (W.F) 61.8 1.5 1.1 66 83

95% W.F. + 5% 61.1 1.3 0.7 69 83 M.F

90% W.F. + 60.5 1.3 6.0 42 67 10% M.F

85% W.F. + 59.9 1.4 4.2 56 75 15% M.F

W.F. = Wheat flour M.F: = Watermelon seeds flour.

Fig. (2) Farinogram of wheat flour (control).

Fig. (3) Farinogram of wheat flour with 5% watermelon seed flour.

Fig. (4) Farinogram of wheat flour with 10% watermelon seed flour.

Fig. (5) Farinogram of wheat flour with 15% watermelon seed flour.

4.5.2. Extensogram characteristics The extensogram characteristics of wheat flour, and wheat flour with watermelon seeds flour blends were presented in Table (6) and Fig. (6,7,8 and 9). The energy of wheat flour at 45, 90 and 135 minutes, was 56, 56 and 52 cm2, respectively. The consistency (resistance) at 45, 90 and 135 minutes for wheat flour was 226, 238 and 256 BU, respectively. The extensibility at 45, 90 and 135 minutes for wheat flour was 153, 146 and 131 mm, respectively. The ratio number, which is the ratio of resistance at maximum to extension at 45, 90 and 135 minutes for wheat flour was 1.5, 1.6 and 1.9 minutes, respectively. As the time increased the energy and extensibility decreased, while the resistance and ratio number increased. The results showed a decrease in the energy with the addition of watermelon seeds flour except at 5% addition at 45 and 135 minutes. The resistance of wheat flour increased as the time increased from 45 to 135 minutes except at 5% watermelon seeds flour blends, the resistance decreased from 227 at 45 minutes to 214 at 90 minutes and increased again to 246 at 135 minutes. The resistance at 45 minutes increased with the addition of melon seed flour, except at 10% which decreased from 227 BU to 194 BU, and at 90 minutes decreased with the addition of 5% of watermelon seed flour from 238 to 214 BU, and increased again at 10% addition to 225 B.U, but decreased again at 15% addition to208 B.U., the resistance at 135 minutes decreased with the addition of watermelon seeds flour except at 15% watermelon seeds flour blends increased from 236 to 280 B.U. The extensibility decreased with increasing time from 45 to 135 minute. The extensibility decreased with 5 and 15% blends, while with 10% watermelon seeds flour blends extensibility increased from 152 to 155 BU, from 144 to 149 BU, and from 134 to 141 BU at 45, 90 and 135 minutes, respectively. As the time increased from 45 to 135 minutes, the ratio increased. The ratios decreased with 5 and 10% blends, while with 15% watermelon seeds flour blends ratio increased from 1.3 to 1.4, from 1.5 to 1.8 and from 1.7 to 2.4 BU at 45, 90 and 135 minutes, respectively. Generally, as the percentage of watermelon seeds flour increased, the energy and resistance decreased, and extensibility increased, showing softer dough. These results were in agreement with that reported by Yaseen et al. (1991) who found that the dough extensibility, resistance to extension and dough energy were minimized with increasing tomato seed meal in the formula containing wheat flour.

Table 6: Extensogram readings of wheat flour with watermelon seed flour.

Energy (cm2) Resistance Extensibility Ratio Number Flour (BU) (mm) (R.N) blends 45 90 135 45 90 135 45 90 135 90 135 mi min min mi min min mi min 45 min min min n . n . n . min .

Control 56 56 52 22 238 256 15 146 13 1. 1.6 1.9 (W.F) 6 3 1 5

95% 57 54 54 22 214 246 15 144 13 1. 1.5 1.8 W.F. + 7 2 4 5 5% M.F

90% 47 53 50 19 225 236 15 149 14 1. 1.5 1.7 W.F. + 4 5 1 3 10% M.F

85% 44 36 44 19 208 280 14 115 11 1. 1.8 2.4 W.F. + 6 1 5 4 15% M.F

W . F . = W h e a t f l o u r .

M.F. = Watermelon seed flour.

4.6. Organoleptic quality of biscuits Table (7) shows the effect of watermelon seeds flour on sensory evaluation (color, odor, surface feel, taste, mouth feel, texture and total scores) of biscuits made from wheat and watermelon seed flours ranging from 0 to 15% with 5% increment. 4.6.1. Color As Table (7) showed, the color has not significantly (P≤0.05) changed with the increasing percentage of watermelon seed flour according to the panelists. Although biscuits made with 5% watermelon seed flour blend and the control gained the higher score than the other two additions (10 and 15%). They all gained the same very good desirable color. 4.6.2. Odor Table (7) shows the odor of biscuits made with wheat and watermelon seed composite flours. Biscuits made with 10% watermelon seed flour gained a higher score (7.31) and biscuits made with 15% gained a lower score (7.06). Statistically, there are insignificant differences (P>0.05) between all types of biscuits. All types of biscuits gained the same very good desirable odor. 4.6.3. Surface feel The score of biscuits surface feel made from wheat and watermelon seed composite flours is shown in Table (7). The surface feel score for biscuits made with 10% watermelon seed flour gained a higher score (7.33) and biscuits made with 15% gained a lower score (6.93). There were no significant differences (P>0.05) between all types of biscuits, all types of biscuits gained the same very good smooth surface feel.

4.6.4. Taste The scores of biscuit taste made from wheat flour with watermelon seed composite flour is shown in Table (7). The taste score for biscuit made with 10% watermelon seed flour gained a higher value (8.10) and biscuits made with 5% gained a lower value (7.43). Although statistically, there were insignificant difference (P>0.05) between all types of biscuits, but the addition of 10% changed from very good to excellent pleasant taste. 4.6.5. Mouth feel The scores of biscuit mouth feel made from wheat and watermelon seed composite flours are shown in Table (7). The mouth feel score for biscuits made with 15% watermelon seed flour gained a higher value (8.19) and the biscuits made with 5% and control gained the lower value (7.33). Although, statistically there were insignificant differences (P>0.05) between all types of biscuits, but the addition of 10% and 15% changed from very good to excellent mouth feel. 4.6.6. Texture Table (7) shows the texture of biscuits made from wheat and watermelon seed composite flours. Biscuits made from 10% watermelon seed flour gained a higher score (7.67), and biscuits made with 5% gained a lower score (7.29). Statistically, the texture of all types of biscuits showed insignificant difference (P>0.05). All types of biscuits gained the same very good crispy texture. 4.6.7. Total score Table (7) shows the overall quality of biscuits made with wheat and watermelon seed composite flours. Biscuits made with 10% watermelon seed flour blends gained higher score (45.97), while biscuits made with 5% gained lower score (44.18). There were no significant difference between all types of biscuits, so all types of biscuits gained a very good quality.

Table (7): Quality attributes of biscuit

Blends Color Odor Surface Taste Mouth feelTexture Total scores feel

W.F (control) 7.99(±1.56)a 7.13(±2.26)a 7.28(±1.59)a 7.60(±1.30)a 7.33(±1.30)a 7.33(±1.63)a 44.67(±6.50)a

95% W.F+5% M.F 7.99(±1.32)a 7.07(±1.78)a 7.07(±1.62)a 7.43(±0.94)a 7.33(±1.30)a 7.29(±1.40)a 44.18(±6.57)a

90% W.F+10% M.F 7.60(±1.40)a 7.31(±1.80)a 7.33(±1.40)a 8.10(±1.11)a 8.13(±1.07)a 7.67(±1.45)a 45.97(±6.35)a

85% W.F+15% M.F 7.40(±1.59)a 7.06(±1.39)a 6.93(±1.71)a 7.63(±1.42)a 8.19(±1.58)a 7.39(±1.68)a 44.37(±6.58)a

Mean values (±SD) having different superscript letters in columns differ significantly (P≤0.05). W.F = Wheat flour. M.F = Watermelon seeds flour 4.7. Biscuits made from composite flours Table (8) shows the width, thickness and spread ratio of biscuits made from wheat flour and watermelon seed flour from 0 to 15% with 5% increment of watermelon seeds flour. 4.7.1.Width The result of biscuits width made from wheat flour (control) was 6.12 cm significantly higher than the width of the other types of biscuits, which were made with watermelon seed flour, as shown in Table (8). As the percentage of watermelon seed flour increased, the width of biscuits decreased, but in 15% increased again. 4.7.2. Thickness From Table (8) the thickness of biscuits made from wheat flour (control) was 0.59 cm significantly higher than the other types of biscuits, which were made with watermelon seed flour. The thickness of biscuits decreased to 0.52 cm in 5% and 10% additions, and increased again to 0.53 cm in 15%. 4.7.3. Spread ratio From Table (8), the spread ratio of biscuits made with 15% watermelon seed flour blends was 10.9, significantly higher than the other types of biscuits, while the spread ratio of biscuits made from wheat flour (control) and 5% addition gained the same value (10.2), so there were no significant difference between them, and by the addition of 10% the spread ratio decreased to 9.7. Table (8): Physical characteristics of biscuit

Blends Thickness width Spread ratio (cm) (cm) (wid/th)

W.F (control) 0.59 (±0.10)a 6.12(±0.01)a 10.2(±0.01)b

95% W.F+5% M.F 0.52(±0.01)c 5.28(±0.01)c 10.2(±0.01)b

90% W.F+10% M.F 0.52(±0.01)c 5.05(±0.01)d 9.70(±0.01)c

85% W.F+15% M.F 0.53(±0.01)b 5.90(±0.10)b 10.9(±0.01)a

Mean values (±SD) having different superscript letters in columns differ significantly (P≤0.05). W.F = Wheat flour. M.F = Watermelon seeds flour.

Plate (3) Biscuits made from wheat and watermelon seed composite flours.

(A) Wheat flour (control). (B) 95% wheat flour + 5% watermelon seed flour. (C) 90% wheat flour + 10% watermelon seed flour. (D) 85% wheat flour + 15% watermelon seed flour.

CHAPTER FIVE

CONCLUSIONS AND RECOMMENDATIONS

1. The results of this study indicated that watermelon seeds flour had the

higher value of protein, ash, oil and fiber contents than wheat flour,

except carbohydrate content was higher in wheat.

2. Tannin content did not show variation between wheat flour and

watermelon seeds flour, watermelon seeds flour had higher phytic

acid content compared to the wheat flour.

3. Watermelon seeds flour had a higher value of Ca, K, Na, Fe, Mn and

Zn than wheat flour, except Mg was higher in wheat flour.

4. Lysine and methionine were the limiting amino acids, while glutamic

acid was marginal in watermelon seeds flour.

5. Wheat flour with 15% watermelon seeds flour showed biscuits with

higher spread ratio than the biscuits made from wheat flour.

6. The acceptability and overall quality of biscuits made from wheat flour

with different levels of watermelon seeds flour were similar to that

of biscuits made from wheat flour. Blends are even better in some

characters.

Recommendation:

1. Due to its high protein, oil and mineral contents watermelon seeds, are

recommended for human food or its addition to some food to

improve its nutritional quality.

2. Further studies are needed, in this field to investigate the addition of

watermelon seeds flour and soy bean flour to wheat flour to make

high nutritive biscuits.

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