Kwara State Polytechnic, Ilorin Operation And Maintenance Of Steam Boiler

Abstract

Biscuits hold an important position in snack foods due to the variety in taste, crispiness and digestibility. Composite flours have better nutritional quality and would be highly desirable for the production of nutritious biscuit. A study was carried out to develop biscuits from the flour of sweet potato (Ipomoea batatas L.) and wheat (Triticum aestivum L.) and to evaluate the quality characteristics of the product. The mature sweet potatoes (cv. Wariapola Red) were procured from the commercial growers. Tubers were washed, peeled, cut into thin slices of 1 mm thickness and dried in the sun until the pieces were quite brittle. The dried chips were milled, passed through a 250 µm sieve and packed in air tight containers. Different composite blends of wheat flour and sweet potato flour were mixed in the ratios of 100:00, 80:20, 60:40, 40:60, 20:80 and 00:100. The nutritional analysis of sweet potato flour confirmed that it contains 2.3% protein, 9.4% dietary fibre and 85.5% soluble carbohydrates. Physical characteristics such as thickness, volume and spreading factor of the cookies decreased from 0.969 to 0.910 cm, 41.66 to 30.41 cm³ and 6.43 to 5.61, respectively, with increasing of sweet potato flour. The moisture, ash, fibre and soluble carbohydrate content increased significantly (p<0.05) from 1.33 to 1.37%, 2.07 to 2.4%, 2.14 to 8.7, and 80.86 to 85.97%, respectively, while protein content decreased significantly (p<0.05) from 7.04 to 6.22 with the increase in sweet potato flour from 0 to 100% of the composite flour for biscuits. The sensory analysis showed that the cookies supplemented with 40% sweet potato flour were well acceptable in terms of colour, texture, taste and overall acceptability compared to other treatments. The mixture of 40% sweet potato flour and 60% wheat flour was successful for the formulation of biscuits with better nutritional and organoleptic qualities within the universally accepted standards. The glycemic indices for biscuits produced from wheat and potato flour were found to be 84, 92 respectively. The analysis of variance (F= 0.05) carried out showed that the method of preparation of the biscuits did not affect the glycemic indices of the food, there is also no significant differences (p< 0.05) in the glycemic indices of biscuits produced from wheat and potato flour. The diets were within the high glycemic index range of above 70. From these results, it can be concluded that potato flours are of high glycemic index than wheat. The outcome of this research can be used as valuable information for the development of high fibre low gluten sweet biscuits.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

• INTRODUCTION
• Background of the study
• Problem statement
• Aim and objectives of the study
• Scope of the study
• Significance of the study
• Research hypothesis
• Research question
• Organisationofthestudy

CHAPTER TWO

LITERATURE REVIEW

• Biscuits
• Historical Background of Biscuit
• wheat
• Glycaemic index concept
• Glycaemic load concept
• Portion size and glycaemic control
• Determination of glycaemic index
• Glycaemic Load and Health
• Glycaemic load and diabetes
• Glycaemic load and coronary heart diseases
• Glycaemic load and obesity
• Factors Affecting Preference and Food Choice

CHAPTER THREE

• MATERIALANDMETHODS
• Preparation of sweet potato flour
• Experimental plan
• Development of wheat and sweet potato blended biscuit
• Nutritional analysis of wheat – sweet potato flour blended biscuits
• Determination of Glycemic Index

CHAPTER FOUR

4.0      RESULT AND DISCUSSION

CHAPTER FIVE

• Conclusion and recommendation
• Reference
• CHAPTER ONE

1.0                                        INTRODUCTION

1.1                           BACKGROUND OF THE STUDY

Sweet potatoes (Ipomoea batatas L.) are an excellent source of nutrition and considered as one of nature’s most perfect vegetables. Among the world’s major food crops, sweet potato produces the highest amount of edible energy per hectare per day (Sukhcharn et al., 2008). Sweet potato consists of about 70% carbohydrates of which the major portion is starch, which can be utilized as a functional ingredient in certain food preparations. They are an excellent source of beta-carotene and also a good source of vitamin C and manganese. A mixture of wheat (Triticum aestivum L.) flour and sweet potato flour could make a good baking product, which should increase the nutritive values in terms of fiber and carotenoids (Hagenimana et al., 1992) and the economic value of the final product. This helps in lowering the gluten level and prevents manifestation of coeliac disease.

Starch manufacture is the main industrial utilization of sweet potatoes, which has been used in the preparation of noodles, bakery foods, snack foods, confectionery products and for alcohol production and in brewing industries. The functional properties of the flour are provided not only by the starch, but also by other flour components. The flour is used as a dough conditioner for bread, cookies and cakes, and adds natural sweetness, colour and flavour to processed food products (Giami et al., 2014). The rheological characteristics of the dough are very important.