Contribution Of Lactic Acid Bacteria To Improve The Nutritive Quality Of Pentraclethra Macrophylla Enriched With Brewer’s Yeast

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