Screening Of Some Lactic Acid Bacteria Isolated From Selected Nigerian Fermented Foods For Vitamin Production

ABSTRACT

Thiamine, riboflavin and niacin are among the essential vitamins required for normal physiological function that cannot be synthesized by the body, and thus must be obtained from dietary source.  Five lactic acid bacteria were isolated from selected Nigerian fermented foods (Yoghurt, ogi, ogiri, ugba). The isolates were identified based on cultural and biochemical characteristics. All the isolates were screened for thiamine, riboflavin and niacin production. Thiamine, riboflavin and niacin produced were quantified. The five lactic acid bacteria isolated were Lactobacillus plantarum,Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus casei and Lactococcuslactis. The most frequent isolate was Lactobacillus plantarum (100%) followed by Lactobacillus caesi (75%). Lactobacillus brevis, Lactobacillus fermentum and Lactobacillus lactis were the least isolates having (50%) occurrence each. Lactobacillus plantarum produced the highest amount of thiamine (5.8833µg/100ml) and riboflavin (5.0400µg/100ml) while Lactobacillus lactis had the least thiamine (5.2267µg/100ml) and Lactobacillus caesi had the least riboflavin (4.8300µg/100ml). Lactobacillus casei produced the highest niacin (1.6433µg/100ml) while Lactobacillus fermentum had the least (1.2900µg/100ml). This study revelsLactobacillus plantarum as the most efficient thiamine and riboflavin producer. Lactobacillus caseiproduced the most niacin. 

TABLE OF CONTENTS

Title page ﾿ i

Certification ﾿ ii

Dedication ﾿ iii

Acknowledgement ﾿ iv

Tables of contents ﾿ v

List of tables ﾿ vi

Abstract ﾿ vii

Chapter One

1.0 ﾿ Introduction ﾿ 1

1.1 ﾿ Aim ﾿ 2

1.2 ﾿ Objectives ﾿ 2

Chapter Two

2.1 ﾿ Lactic Acid Bacteria (LAB) ﾿ 3

2.2 ﾿ What are Lactic Acid Bacteria? ﾿ 3

2.3. ﾿ Physiology and Morphology ﾿ 5

2.4  ﾿ General Description ﾿ 7

2.5  ﾿ Genetics ﾿ 9

2.6. ﾿ Application of Lactic Acid Bacteria ﾿ 10

2.7.  ﾿ Lactic Acid Bacteria as Source of Probiotics ﾿ 11

2.7.1 ﾿ Probiotics and Health ﾿ 13

2.8 ﾿ Lactic Acid Bacteria as Source of Starter Cultures ﾿ 14

2.8.1 ﾿ Starter Culture and Functional Starter Cultures in Fermentation of Foods ﾿ 14

2.8.2 ﾿ Probiotics as Functional Starter Culture ﾿ 14

2.8.3 ﾿ Functional Starter Cultures in Fermented Dairy Products ﾿ 17

2.8.4 ﾿ Functional Starter Cultures in Fermented Non Dairy Products. ﾿ 17

2.8.4.1. Fermented Meat and Meat Products ﾿ 17

2.8.4.3. Starter Culture in Silage ﾿ 17

2.9 ﾿ Lactic Acid Bacteria as Source of Antimicrobial Agents. ﾿ 18

2.9.1 ﾿ Bacteriocins ﾿ 19

2.10. ﾿ Lactic Acid Bacteria as a Source of Vitamins ﾿ 19

2.10.1 ﾿ Folate ﾿ 20

2.10.2. Vitamin B12 ﾿ 21

2.10.3 Vitamin K ﾿ 21

2.10.4 Riboflavin ﾿ 22

2.11. ﾿ Lactic Acid Bacteria as Source of Enzymes ﾿ 22

2.12. ﾿ Lactic Acid Bacteria as Source of Exopolysaccharides ﾿ 23

2.13. ﾿ Lactic Acid Bacteria as Source of Low-Calories Sweeteners. ﾿ 24

Chapter Three

3.0 ﾿ Materials and Method ﾿ 25

3.1 ﾿ Source of Materials ﾿ 25

3.2 ﾿ Sample Preparation ﾿ 25

3.3 ﾿ Media Preparation ﾿ 25

3.4 ﾿ Isolation of Lactic Acid Bacteria ﾿ 26

3.5. ﾿ Morphological Identification of Bacterial Isolates. ﾿ 26

3.5.1 ﾿ Gram Staining ﾿ 26

3.5.2 ﾿ Biochemical Parameters. ﾿ 27

3.6.1. ﾿ Determination of Thiamine (Vitamin B1) ﾿ 29

3.6.2 ﾿ Determination of Riboflavin (Vitamin B2¬) ﾿ 31

3.6.3. ﾿ Determination of Niacin (Vitamin B3) ﾿ 31

3.7 ﾿ Statistical Analysis ﾿ 32

Chapter Four

Results ﾿ 33

Chapter Five

5.1 ﾿ Discussion ﾿ 38

5.2 ﾿ Conclusion ﾿ 40

References

Appendix