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The Use Of Bitterleaf (vernonia Amygdalina) Extract As A Means Of Extending The Shelf-life Of Locally Brewed Sorghum Beer

THE USE OF BITTERLEAF (VERNONIA AMYGDALINA) EXTRACT AS A MEANS OF EXTENDING THE SHELF-LIFE OF LOCALLY BREWED SORGHUM BEER

                                        ABSTRACT

Locally brewed beer (sorghum beer) is an indigenous alcohol average. 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 CONTENT

CHAPTER ONE

1.0 INTRODUCTION

1.1 AIMS AND OBJECTIVES

CHAPTER TWO

2.0 LITERATURE REVIEW

2.1 GENERAL DESCRIPTION OF CEREALS

2.1.1 GENERAL CHARACTERISTICS OF CEREALS

2.2 SORGHUM

2.2.1 GENERAL DESCRIPTION OF SORGHUM

2.2.2 SCIENTIFIC CLASSIFICATION OF SORGHUM

2.2.3 GRAIN COMPOSITION AND NUTRITIVE VALUE

2.2.4 CULTIVATION AND USES

2.3 MILLET

2.3.1 GENERAL DESCRIPTION OF MILLET

2.3.2 BOTANICAL CLASSIFICATION OF MILLET

2.3.3 PEST AND DISEASES OF MILLET

2.3.4 USES OF MILLET

2.4 BREWING

2.4.1 HISTORY OF BREWING

2.4.2 BREWING PROCESSES

2.4.2.1 EUROPEAN BREWING PROCESS

2.4.2.2 INDIGENOUS AFRICAN BREWING PROCESS

2.5 RAW MATERIALS FOR BREWING

2.5.1 STARCH SOURCE

2.5.2 ADJUNCTS

2.5.3 WATER

2.5.4 HOPS

2.5.4.1 CHARACTERISTICS OF HOPS

2.5.4.2 TROPICAL HOP SUBTITUTES FOR BEER BREWING

2.5.5 YEAST

2.5.5.1 BAKER’S YEAST

2.5.5.2 BREWER’S YEAST

2.6 BIOCHEMISTRY OF BREWING PROCESSES

2.6.1 MALTING AND KILNING

2.6.2 MILLING

2.6.3 MASHING

2.6.4 SOURING

2.6.5 WORT BOILING

2.6.6 FERMENTATION

2.6.6.1 ALCOHOL FERMENTATION

2.6.6.2 TOP FERMENTATION

2.6.6.3 BOTTOM FERMENTATION

2.6.7 PACKAGING

2.7 SPOILAGE

2.7.1 MICROORGANISM THAT DETERIORATE BEER

2.8 TYPES OF BEER

2.8.1 EUROPEAN BEERS

2.8.2 INDIGENOUS AFRICAN BEERS

2.9 EFFECTS OF ALCOHOL ON MAN

2.9.1 ALCOHOL AND HEALTH

CHAPTER THREE

3.0 MATERIALS AND METHODS

3.1 MATERIALS

3.1.1 CHEMICALS AND REAGENTS

3.1.2 GLASSWARES AND EQUIPMENT

3.1.3 PREPARATION OF SAMPLES

3.2 METHODS

3.2.1 METHOD OF PREPARATION OF SORGHUM BEER

3.2.2 ACTIVATION OF YEAST

3.2.3 PREPARATION OF BITTERLEAF EXTRACT

3.2.4 PREPARATION OF REAGENT

3.2.4.11% PHENOLPHTHALEIN

3.2.4.2 0.1M NaOH SOLUTION

3.3 METHOD OF CHEMICAL ANALYSIS

3.3.1 TOTAL ACIDITY

3.3.2 FIXED ACIDITY

3.3.3 VOLATILE ACIDITY

3.3.4 PH DETERMINATION

3.3.5 SPECIFIC GRAVITY

3.3.6 TOTAL DISSOLVED SOLID

3.3.7 TOTAL SUSPENDED SOLIDS

3.3.8 ETHANOL CONTENT

3.3.9 MICROBIAL COUNT

3.3.9.1 PROCEDURES FOR THE PREPARATION OF MEDIA

3.3.9.2 PROCEDURE FOR CULTURING PLATES

3.3.9.3 PROCEDURE FOR IDENTIFICATION OF ORGANISMS

CHAPTER FOUR

4.0 RESULTS

4.1 RESULTS FOR TOTAL ACIDITY, FXED ACIDITY, VOLATILE ACIDITY          AND PH OF SORGHUM BEER

4.2THE GRAPHICAL REPRESENTATION OF TOTAL ACIDITY, FIXED        ACIDITY, VOLATILE-ACIDITY AND PH RESULT

4.3 RESULTS FOR ETHANOL CONTENT, SPECIFIC GRAVITY, TDS AND TSS    FOR SORGHUM BEER

4.4 GRAPHICAL REPRESENTATION OF ETHANOL CONTENT, SPECIFIC   GRAVITY, TOTAL DISSOLVED SOLIDS (TDS) AND TOTAL     SUSPENDED SOLID (TDS) RESULTS

4.5 AVERAGE MEAN PARAMETERS GENERATED FROM HOPPED AND      UNHOPPED SORGHUM BEER

4.6 GRAPHICAL REPRESENTATION OF THE AVERAGE PARAMETERS      GENERATED FROM SORGHUM BEER WITH AND WITHOUT        HOPS

4.7 MICROBIAL COUNT FOR BENCH STORED SORGHUM BEER WITH AND WITHOUT HOP

CHAPTER FIVE

5.0 DISCUSSION

5.1 CONCLUSION

5.2 RECOMMENDATION

REFERENCES

APPENDIX A

APPENDIX B

APPENDIX C

LIST OF TABLES

Table 1: Alcoholic beverage produced from cereals in Africa

Table 2: Average kaffir beer analysis

Table 3: Total acidity, Fixed acidity, Volatile acidity and PH values of sorghum beer         with and without hop substitute

Table 4: Ethanol content, Specific gravity (day 1-day 5) and Total Dissolved Solids         and Total Suspended Solids (day I and day 5) values of sorghum beer with and         without hop substitute

Table 5: Specific gravity, Total acidity, Fixed acidity, Volatile acidity, TDS, TSS        and   pH values for with and without hop sorghum beers

Table 6: Frequency of distribution of isolates in Sorghum beer with hops

Table 7: Table 7: Frequency of distribution of isolates in Sorghum beer without hops

LIST OF FIGURES

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