quality assessment and glycemic indices of biscuits produced from wheat (triticium aestivum) and whole potatoes flour

Description

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
• References

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.

Biscuits are flour confections produced from dough and baked to a very low moisture content within a short period of time to make them flaky and crispy. The consumption of biscuits and other bakery products such as bread and cakes prepared from wheat flour has become very popular in the world, especially, among children (Ayo and Nkama,2003).

Okaka (2017) described the production of biscuits as a mixture of flour and water but may contain fat, sugar and other ingredients mixed together into dough which is rested for a period and then passed between rollers to make a sheet .

Wheat (Triticum aestivum L.) is one of the important grain crops produced worldwide. According to the FAO, 2005 report, about 620 million metric tons of wheat was produced from 217 million hectares in the year 2005/06 with an average yield of 2.85 metric tons per hectare. It is grown on larger area than any other crop and its world trade is greater than for all other crops combined and it is easily stored and transported (Slafer & Satorre, 2019). Wheat is an important source of essential nutrients like carbohydrates, proteins, Vitamins B, iron, calcium, phosphorous, zinc, potassium and magnesium (shewry et al, .2019). Wheat is used several ways in food: pasta, noodles, rolls, bread, biscuits, cakes, crackers, cookies, Steamed bread.

In developing countries like Nigeria, people are traditionally dependent upon cereals and are generally unaware of the nutritional value of potatoes. Therefore, it is essential that potato consumption is increased to sustain this increase in production and to ensure remunerative prices to the farmers as well. Under the existing circumstances, processing of the bulky perishable potatoes into various processed products is a viable option which can help extend the storage life, solve the storage problem, cater to the consumer preference belonging to different age groups and social strata and serve as a means to increase the supply in off seasons thus maximizing potato utilization.

The objective was to assess the nutritional quality and glycemic indices of biscuits produced from wheat and whole potato flour

1.2                                    PROBLEM STATEMENT

Food deficit is increasing day by day. So it is a burning question to meet the food requirement of millions of people living in poverty in the third world. Attempts to resolve the problems of food production have placed great emphasis on increasing the production and productivity of grain crops, but little attention has been given to crops such as potato (Solanum tuberosum L)( Muhammad et al., 2014).

Biscuits are flour confections produced from dough and baked to a very low moisture content within a short period of time to make them flaky and crispy. The consumption of biscuits and other bakery products such as bread and cakes prepared from wheat flour has become very popular in the world, especially, among children (Ayo and Nkama,2013).

The use of sweet potato flour for supplementing with wheat flour on the baking could substantially reduce need for wheat, reduction in the usage of sugar   on   the    products,    and    increase    the    value    of    sweet    potato. The Government of Nigeria aims to reduce per capita consumption of wheat flour from the current quantity of 26 Kg per annum to 16 Kg per annum (Emanthi, 2012). Our approach in the present study was to replace the wheat flour content in biscuit by sweet potato flour (gluten-free flour) with a view to increase the content of fiber and other nutrients.

An approach in the present study will replace the wheat flour in biscuits by potato flour (gluten free flours) in order to increase the fibre and other nutrients. Therefore partial substitution of wheat with potato flour is one of the most cost effective ways of producing biscuits with better nutritional quality and optimizing the daily increasing price of wheat in the world market. This is because of cheap cost of potato and expensive cost of wheat which do not meet the need of our populations. In addition to this, the use of potato flour for different food product development will be an opportunity to enhance the use the underutilized root crops like potato with value addition and minimizing its postharvest loss.

1.3                    AIM AND OBJECTIVES OF THE STUDY

The main aim of this work is to assess the nutritional quality and glycemic indices of biscuits produced from wheat and whole potato flour. The objectives of the study are:

1. To determine the nutritional and glycemic difference between biscuit made from wheat and potatoes flour.
2. To determine the proximate composition and quality parameters of the biscuits

• To identify a suitable formulation of wheat/ potato flour for biscuit making.

1. To evaluate consumers acceptance of biscuit made from wheat/ potato

1.4                                     SCOPE OF THE STUDY

This study focuses on the evaluation of  the quality assessment and glycemic indices attributes produced from composite flours of wheat and potato as well as to determine the effect of incorporation of potato at different levels for biscuit production.

1.5                             SIGNIFICANCE OF THE STUDY

Therefore research toward wheat biscuit product development that comprises potato as component will address the nutrition deficiency challenges and postharvest minimization of potato. It will also contribute in the promotion of potato production, increase farmer’s income, create more jobs, reduce dependence and consequently the foreign exchange expended on wheat importation. These would add up to an improvement of food and livelihood security for the vast majority of the citizenry.

The data generated in this study may provide vital information on the process involved in formulating, planning, and utilizing the good quality wheat and potatoes composite flour in producing biscuits in food industries (Flour and baking industries).

1.6      RESEARCH HYPOTHESIS

H0 = There is no significant difference in the glycemic load of biscuits produced from wheat and potato flour.

H1= There is a significant difference in the glycemic load of biscuits produced from wheat and potato flour.

1.7      RESEARCH QUESTION

1. Does biscuits produced from potato flourhave high glycemic index than the one produced with wheat flour?
2. What is the glycemic index of potato flour?

• Does potato have high glycemic index than wheat flour?

1. What is the glycemic index of wheat flour?

1.8                                   PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.