Evaluation Of Microbial Succession And Physio-Chemical Changes In Fermentation Of Cassava For Garri

ABSTRACT

The evaluation of microbial succession of Cassava for Garri processing was carried out using grated or homogenized cassava for microbial analysis. The media used were Nutrient agar for total viable count, Violet red bile agar for enumeration of Enterobacteracea, Potatoe dextrose agar for enumeration of yeast and moulds and De, man Rogosa and sharpe agar for enumeration of Lactic acid bacteria. A serial dilution was done and Pour plate method was employed, Gram staining and bio-chemical tests were used for identification of the bacteria.The total aerobic plate count for the fermenting cassava ranged from 5.4 x109 C.F.U/ML to 2.5 x 103 C.F.U/ML, for yeast and mould count 5.2 x 109 C.F.U/ML to 6.5 x 103 C.F.U/ML and Lactic acid bacteria ranged from 9.8 x 109 C.F.U/ML to 4.4 x 103 C.F.U/ML and Enterobacteracea ranged from 5.2 x 109 to 6.5 x 103 C.F.U/ML respectively. The bacteria isolated from the fermenting cassava were Lactobacillus species, Aspergellus niger, Bacillus subtilis, Corynebacterium manihot, Leuconostoc mesenteroides, Geotrichum species, Saccharomyces cerevisea. An evaluation of microbial succession done revealed that Bacillus subtilis and Lactobacillus plantarum showed the highest acid producing ability, Bacillus subtilis and Klebsiella species contributed to the fermenting of the cassava The study concluded that a large number of microorganisms are involved in fermentation of cassava.

TABLE OF CONTENT

Certification ﾿ i

Dedication ﾿ ii

Acknowledgement ﾿ iii

Table of content ﾿ iv-vi

Abstract ﾿ vii

CHAPTER ONE

1.0 INTRODUCTION ﾿ 1

1.1 Justification of the Study ﾿ 3

1.2 General Objectives ﾿ 3

1.3 Aims and Objectives of the Study ﾿ 3

CHAPTER TWO

2.0 LITERATURE REVIEW 

Overview on Cassava (Manihot Esculenta Crantz) ﾿ 4

2.2 Pest and Diseases ﾿ 4

2.3 Economic Importance ﾿ 5

2.4 Composition ﾿ 5

2.5 Toxic Compounds in Cassava ﾿ 6

2.6 Toxic Effects and Diseases Associated with Cyanide Exposure ﾿ 9

2.7 Diseases Related To Cassava Toxicity ﾿ 11

2.8 Processing into Different Products ﾿ 12

2.8.1 Garri: ﾿ 12

2.8.2 Fufu: ﾿ 13

2.8.3  Chickwangue: ﾿ 14 

2.9 Cassava Processing Techniques for Garri ﾿ 14

2.9.1 Peeling ﾿ 15

2.9.2 Grating and Chopping ﾿ 15

2.9.3 Drying (Sun- And Oven-Drying) ﾿ 15

2.9.4 Fermentation ﾿ 16

2.9.4.1 Physical and Biochemical Changes During Cassava Fermentation. ﾿ 18

2.9.4.2 Biochemical Changes ﾿ 19

CHAPTER THREE

3.0 MATERIALS AND METHODS ﾿

3.1 Study Area ﾿ 22

3.2 Sterilization of Materials ﾿ 22

3.3 Fermenting Procedure ﾿ 22

3.4 Microbiological Population Studies ﾿ 24

3.4.1 Media Used ﾿ 23

3.5 Isolation of Bacteria and Yeast ﾿ 23

3.6 Isolation Using Pour Plate Method ﾿ 24

3.6.1 Sub-Culturing:  ﾿ 24

3.6.2 Identification of Bacterial Isolates ﾿ 24

3.6.3 Identification of Fungal Isolates ﾿ 24 

3.7 Gram Staining ﾿ 24

3.8 Biochemical Tests ﾿ 25

3.8.1 Catalase Test: ﾿ 26

3.8.2 ﾿ Indole Test ﾿ 26

3.8.3 ﾿ Citrate Test ﾿ 26

3.8.4 Oxidase Test ﾿ 27

 3.8.5 Carbohydrate Fermentation Test: ﾿ 27

3.8.5 Motility Test: ﾿ 27

3.9 Determination of Physiocochemical Parameters ﾿ 27

3.9.1 PH ﾿ 28

3.9.2 Titrable Acidity ﾿ 28

3.9.3 Cyanide Content ﾿ 28

3.9.5 Fermentation Modulation ﾿ 29

3.9.6 Effect of Temperature ﾿ 29

CHAPTER FOUR

4.0 RESULTS ﾿ 30

4.1 Microbial Counts ﾿ 30 

4.2 Microbial Succession during Fermentation of Cassava for Garri Production ﾿ 30

4.3 Identification of Organisms ﾿ 31

4.9.2 Effect of PH, Titrable Acidity (%) and Cyanide Content on Cassava Fermentation ﾿ 39

4.9.3 Fermentation Modulation ﾿ 39

Discussion ﾿ 40

CHAPTER FIVE

5.1 Conclusion ﾿ 44

References ﾿ 4