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

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.

TITLE PAGE

CERTIFICATION

DEDICATION

ACKNOWLEDGEMENTS

ABSTRACT

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

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

2.7      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

3.2.4.1 1% 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

3.3.7   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

4.2      THE 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