ABSTRACTS

The fermentative production of cassava (Manihot esculenta crantz) flour was done in two different methods, which were the fixed and unfixed fermentation method. The cassava tubers were harvested from the N.R.C.R.I, Umudike, peeled, washed, sliced into big bits of about 5 to 8cm in length and allowed to ferment. The microbial load, succession, pH and cyanide content of the cassava were determined during retting and after production. The results showed the presence of E.coli and Lactobacillus spp, Bacillus spp, Staphylococcus spp, Aspergillus spp, Penicillum spp, yeast, and Geotichum spp  after the first day of fermentation. The dominant organisms after fermentation were Lactobacillus spp and Yeast. The Bacteria load was 1.59x105 to 0.61x105 cfu/g,  fungi load of 1.10x103 to 0.40x 103 cfu/g for fixed fermented cassava flour. The unfixed had the Bacteria load of 1.64 to 0.61x 105 cfu/g and fungi load of 1.10x103 and 0.45x103 cfu/g. On the other hand, the Hydrogen cyanide content and pH decreases as the fermentation period increases in both flour. It is therefore recommended that cassava tubers should be fermented at a minimum of 48 hours as its cyanide content decreases with increase fermentation period.    

TABLE OF CONTENTS

Title page i 

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Figures vii

List of Tables viii

Abstract x

CHAPTER ONE

INTRODUCTION 1

1.1 Background of Study 1

1.2 Aims and Objectives 2

CHAPTER TWO

LITERATURE REVIEW 3

2.1 Description of Cassava 3

2.2 Habitat 3

2.3 History of Cassava 3

2.4 Physiology and Morphology of Cassava Plant 5

2.4.1 Toxicity 5

2.4.2 Varieties 8

2.5 Cassava Processing and Utilization 8

2.6 Nutritional Composition of Cassava 13

2.7 Fermentation Technology 15

2.7.1 Methods of Fermenting Cassava to Flour 16

2.8 Health and Benefits 18

2.9 Acute and Chronic Effects of Cyanide 19

CHAPTER THREE

MATERIALS AND METHOD 21

3.1 Cassava Roots Used 21

3.2 Sample and Media Preparation 21

3.2.1 Fixed Fermentation Method 21

3.2.2 Unfixed Fermentation Method 22

3.3 Media Preparation 24

3.4 Microbial Analysis 24 

3.4.1 Determination of Microbial Load 24

3.4.2 Determination of Microbial Flora 25

3.4.3 Determination of Hydrogen Cyanide 26

3.4.4 Determination of pH 26

3.4.5 Characterization of Bacteria Isolates 27

3.5 Cultural Examination 27

3.5.1 Gram Reaction 27

3.5.2 Microscopic Features 27

3.6 Characterization of Fungi Isolates 28

3.6.1 Viable Counting of the Fungi Growth 28

3.6.2 Identification of Fungi 28

3.6.3 Colony Features of Fungi Isolates 28

3.6.4 Microscopic Features 28

3.6.5 Identification of Isolates 29

3.7 Biochemical Tests 29

3.7.1 Oxidase Test 29

3.7.2 Coagulase Test 29

3.7.3 Citrate Test 29

3.7.4 Indole 30

3.7.5 Test for Carbohydrate 30

CHAPTER FOUR

RESULTS 31

CHAPTER FIVE

DISCUSSION, CONCLUSION AND RECOMMEMDATON 38

5.1 Discussion 38

5.2 Conclusion 39

5.3 Recommendation 39

References 40