ABSTRACT

Lactic acid bacteria (LAB) have been used for the fermentation of food and feed products since ancient days and today their major applications are still in the food industry as starter cultures, where they have been known to improve the nutritional quality of the foods. This study was aimed at determining the contribution of Lactic Acid Bacteria to improve the nutritive value of fermented Pentaclethra macrophylla enriched with Brewer’s yeast. Four LAB species were isolated from Pentaclethra macrophylla of which were Lactobacillus fermentum, Streptococcus lactis, Lactobacillus plantarum, and Leuconostoc mesenteroides based on morphological, biochemical and physiological characteristics. Leuconostoc mesenteroides was the most abundant LAB observed in this study with 43.75% occurrence in the studied samples while Lactobacillus fermentum was the least abundant with 12.5%. The study showed the ability of LAB and Brewer’s yeast to contribute to the fermentation of Pentaclethra macrophylla seeds. This was carried out using the colorimetric method of vitamin determination by Madhavi and Jyothi., (2016). The result showed the concentration of vitamin B2 in unfermented Pentaclethra macrophylla seeds to be 0.0292mg/ml. The concentration of vitamin B2 in fermented Pentaclethra macrophylla seeds (Ugba) with LAB starter culture was 0.0489mg/ml while the concentration of vitamin B2 in Ugba fermented with only Brewer’s yeast was 0.0275mg/ml and that fermented with both LAB and Brewer’s yeast was 0.0522mg/ml. The ability of the LAB isolates and Brewer’s yeast to produce riboflavin can serve as a method of enriching ugba and also fortifying other fermented foods. Hence, using LAB and Brewer’s yeast combined as a starter will be a preferred option than the traditional starters.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgments iv

Table of contents v

List of tables vii

Abstract viii

CHAPTER ONE

INTRODUCTION 1

1.1 Aim and Objectives of the Study 5

1.1.1 Aim 5

1.1.2 Objectives 5

CHAPTER TWO

LITERATURE REVIEW 6

2.1 Fermentation 6

2.1.1 Importance of fermentation 8

2.2 Fermented Foods 10

2.2.1 Ugba and its importance 12

2.3 Lactic acid bacteria 18

2.3.1 African Oil Bean Tree (Pentaclethra macrophylla) 19

2.3.2 Importance of African Oil Bean Tree (Pentaclethra macrophylla) 22

2.4 African Oil Bean Seed 24

2.4.1 Chemical Composition of the Seed 24

CHAPTER THREE

MATERIALS AND METHODS 26

3.1 Source of Raw Material 26

3.2 Materials 26

3.3       Preparation of Ugba 27

3.4 Preparation of Homogenate Ugba Samples 27

3.5 Inoculation of Samples 27

3.6 Colony Count of Isolates 27

3.7 Characterization and Identification of Isolates 28

3.8 Isolation of Lactic Acid Bacteria 28

3.8.1 Phenotypic Characterization 28

3.8.2 Biochemical Characterization 29

3.8.2.1 Gram Staining 29

3.8.2.2 Catalase Test 29

3.8.2.3 Spore Stain Test 30

3.8.2.4 Citrate Test 31

3.8.2.5 Carbohydrate Fermentation Test 31

3.8.2.6 Exopolysaccharide production 32

3.8.3 Physiological Characterization of Lactic Acid Bacteria 32

3.8.3.1 Growth at Different Temperatures 32

3.8.3.2 Salt Tolerance Test 32

3.8.3.3 Growth at Different pH 32

3.9 In Vitro/ Laboratory Fermentation of Ugba Using Lab Isolates for Vitamin            33

Production

3.10     Colorimetric Analysis for Determination of Vitamin  B2 33

CHAPTER FOUR

RESULTS 33

CHAPTER FIVE

DISCUSSION, CONCLUSION AND RECOMMENDATION 39

5.1 Discussion 39

5.2 Conclusion and Recommendation 42

References 44

Appendix I 51