ABSTRACT

The effect of soaking African yam bean (sphenostylis stenocarpa) seeds in water and vanous concentrations of akanwu, NaCi, Na2O3, NaHCO3and  CaCl2 on the water absorption, pH of soak solutions and cooking time were investigated. Addition of salts into cooking water reduced the cooking time a bit lower when compared to cooking time of raw (unsoaked) African yam bean seeds. Hydration coefficient (HC) of the soaked African yam bean (AYB) seeds increased in all the solutions tested as soaking progressed from 6th to the 18th hour (maximum hydration time) before a decrease occurred at the 24^th hour of soaking. At the same concentration of salt, HC was generally higher in samples soaked in Na2CO3and least was Cad2. pH was found to decrease in all the salt solutions tested and the drop in pH occurred over time of soaking. At the same concentration of salts and for the same period of soaking ranging from 6-24 hours, the pH drop was higher in the Na2CO3 soaked samples and the least was CaCl2. Apart from CaCl2, all salt concentrations highly reduce the cooking time. At the same concentration (2.Ogll) and at each of the soaking periods (6,12,18, and 24) hours) investigated, soaking in Na2CO3solution prior to cooking gave a significant (p<O.05) reduction in the cooking time (was highest in Na2CO3) while CaCl2was found to increase the cooking time. The sensory evaluation showed that most of the treated samples were acceptable while CaCl2soaked samples were not acceptable.

TABLE OF CONTENTS

Title Page

Certification ii

Acknowledgement iii

Dedication iv

Table of contents v-vi

List of table vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1-3

1.1 Justification 3

1.2 Objective 3

CHAPTER TWO

2.0 Literature Review

2.1 Agronomical background of African yam bean 4

2.2 Nutritional composition of African yam bean 4-7

2.3 Digestibility 8-9

2.4 Flavour 9

2.5 Off-flavour removal 9-10

2.6 Ant nutritional factors 10-11

2.8 Hard —to-cook (HTC) Phenomenon 11-12

2.9 Uses of African Yam bean 12-13