ABSTRACT

Locally brewed beer (sorghum beer) is an indigenous alcoholic beverage. It is produced mainly from sorghum grain (Sorghum vulgare) and the process of brewing involves malting, mashing, souring, fermentation and packaging. Locally brewed beer without hops has a short shelf-life. The aqueous extract of a tropical plant, bitter-leaf was used as the hop .Two type of drink were produced, one with hops and another without hops. Chemical analyses were carried out on both drinks, which gave a significant (p≤0.05) difference. Sorghum beer with hops has a total acidity of 0.562±0.03, fixed acidity of 0.203±0.001, Volatile acidity 0.360±0.02, PH 3.93, specific gravity 1.042±0.003, total dissolved solids 1.12×105ppm, total suspended solids 1.65×105ppm, ethanol content of 3.43±0.03 respectively. While sorghum beer without hops has a total acidity of 0.652 ±0.002, fixed acidity of  0.176±0.002, volatile acidity of 0.476±0.03, PH of 3.50 specific gravity of 1.021±0.003,  total dissolved solid of 1.15×105ppm, total suspended solids of 1.5×105ppm and an ethanol content  of 3.65±0.02. The microbial count for sorghum beer with hop had no growth of E.coli, streptococcus and staphylococcus but aspergillus was present from the 4th day and heaviest on the 8th day. While the drink without hop had growth of staphylococcus and aspergillus which was seen from the 2nd day and heaviest on the 4th day but E.coli and streptococcus was absent. From the results, the drink with hops could keep for a longer period of time than the other drink without hops. Thus, the aqueous extract of Vernonia amygdalina could extend the shelf-life of locally brewed sorghum beer.

TABLE OF CONTENTS PAGE

Title Page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Table ix

List of Figures x

Abstract xi

CHAPTER 1

1.0 Introduction 1

1.1 Aims and Objectives 2

CHAPTER 2

2.0 Literature Review 4

2.1 General Description Of Cereals 4

2.1.1 General Characteristics Of Cereals 4

2.2 Sorghum 5

2.2.1 General Description Of Sorghum 6

2.2.2 Scientific Classification Of Sorghum 6

2.3 Some Examples Of Indigenous Beers 7

2.3.1 Pito 7

2.3.2 Kunu 7

2.3.3 Burukutu 8

2.4 Physicochemical And Microbiological 9 

2.4.1 Nutritive Value Of Burukutu 10

2.4.2 Economic Value Of Burukutu 10

2.5 Brewing 11

2.5.1 History Of Brewing 11

2.5.2 Indigenous African Brewing Process 12

2.6 Raw Materials For Brewing 12

2.6.1 Starch Source 13

2.6.2 Adjuncts 13

2.6.3 Water 14

2.6.4 Hops 14

2.7 Bitter Leaf (Tropical Hop substitute for Beer Brewing) 17

2.7.1 Botany 19

2.7.2 Major Uses And Functions 19

2.8 Yeast 19

2.8.1 Baker’s Yeast 20

CHAPTER 3

3.0 Materials And Methods 21

3.1 Materials 21

3.2 Methods 21

3.2.1 Collection Of Samples 21

3.2.2 Preparation Of Burukutu 21

3.2.3 Preparation Of Yeast For Inoculation 23

3.2.4 Fermentation Of Sorghum Wort 23

3.3 Physiochemical Analysis 25

3.3.1    Total Acidity 25

3.3.2      Fixed Acidity 25

3.3.3 Volatile Acidity 25

3.3.4 Total Suspended Solid (TSS) 26

3.3.5      Ethanol Content 26

3.3.6   Measurement of Ph 27

3.4          Determination Specific Gravity 27

3.4.1      Total Dissolve Solid 27

3.5 Microbiological Analysis of Burukutu 28

3.5.1 Sterilization of Materials 28

3.5.2 Media preparation 28

3.5.3 Isolation of Identification of Bacteria in Treated and Untreated  Burukutu Sample

3.6 Microbiological Examination Of Isolates 30

3.6.1  Gram Staining 30

3.6.2       Spore Staining 31

3.6.3      Motility Test 31

3.7        Biochemical Test 32

3.7.1      Catalase Test 32

3.7.2      Coagulase Test 32

3.7.3      Oxidation Test 32

3.7.4      Sugar Fermentation Test 33

3.8        Fungal Isolation and Identification 33

3.8.1 Preparation of Bitter leaf Extract 33

3.8.2  Statistical Analysis Method 34

CHAPTER 4

4.0 Results 35

CHAPTER FIVE

Discussion, Conclusion And Recommendation

5.0 Discussion 40

5.1 Conclusion 43

5.2 Recommendation 44

REFERENCES 45

APPENDIX