ABSTRACT

Zobo drink is a non-alcoholic beverage which is consumed in most part of Nigeria, mostly in the northern part of Nigeria It is produced from the dried calyces of the Roselle plant Hibiscus Sabdariffa(Malvaceae)by boiling and filtration. Microbial and sensory attribute of Zobo drink treated with ginger and garlic was investigated. Zobo drink was produced by hot extraction and filtration. The drink obtained was treated with different quantities of ginger and garlic and their effects evaluated during the period of 4 days of storage. A five- fold serial dilution of both treated and control drink samples were carried out for enumeration of microorganisms on appropriate media. The sensory evaluation of the samples was determined using standard methods. Different values of bacterial and fungal counts of both treated and control Zobo drink samples were obtained during the period of monitoring but the total viable bacterial count ranged from 4.11 x 106 – 3.62 x 107 cfu/ml while the fungal count ranged from 4.0 x 106– 3.59 x 107cfu/ml. Similarly, different values of the sensory evaluation of Zobo samples were obtained during the storage period. However, the samples containing ginger and/or mixture of both were better rated in terms of the parameter tested. Shelf-life (based on sensory overall acceptability) of the samples varied with the treatments. The ginger-treated sample showed to extend the shelf-life by 1 day whereas other treated samples showed marginal enhanced shelf-life of 3days. However, untreated control sample exhibited remarkably high microbial loads than the treated samples.

TABLE OF CONTENTS

Certification i

Dedication ii

Acknowledgements iii

Table of Contents iv

List of Tables vi

List of Figures vii

Abstract viii

CHAPTER ONE

1.0Introduction 1

1.1 Aim and objectives of the research 2

CHAPTER TWO

2.0 Literature review 3

2.1 Nutritive values 5

2.2 Economic values 6

2.3 Properties of garlic and ginger 6

CHAPTER THREE

3.0 Materials and methods 9

3.1 Collections of samples 9

3.2 Preparation of Zobodrinks 9

3.3 Treatment of the Zobodrinks with ginger and garlic 9

3.4 Microbiological analysis of samples 10

3.5 Enumeration and characterization of bacteria and fungi 10

3.5.1 Microscopic examination 10

3.5.2 Gram staining 10

3.5.3 Biochemical tests 12

3.5.3.1 Catalase test 11

3.5.3.2 Coagulase test 12

3.5.3.3Indole test 12

3.5.3.4 Citrate utilization test 12

3.6 Motility test 13

3.7 Sensory evaluations 13

CHAPTER FOUR

4.0 Results 14

CHAPTER FIVE

5.0 Discussions 20

5.1 Conclusions 21

5.2 Recommendations 22

References 23

Appendix I 30

Appendix II 31

Appendix III 32