THE USE OF BITTERLEAF 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 shelflife. The aqueous extract of a tropical plant, bitterleaf 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 p0.05 difference. Sorghum beer with hops has a total acidity of 0.5620.03, fixed acidity of 0.2030.001, Volatile acidity 0.3600.02, PH 3.93, specific gravity 1.0420.003, total dissolved solids 1.1210⁵ppm, total suspended solids 1.6510⁵ppm, ethanol content of 3.430.03 respectively. While sorghum beer without hops has a total acidity of 0.652 0.002, fixed acidity of 0.1760.002, volatile acidity of 0.4760.03, PH of 3.50 specific gravity of 1.0210.003, total dissolved solid of 1.1510⁵ppm, total suspended solids of 1.510⁵ppm and an ethanol content of 3.650.02. The microbial count for sorghum beer with hop had no growth of E.coli, streptococcus and staphylococcus but aspergillus was present from the 4^th day and heaviest on the 8^th day. While the drink without hop had growth of staphylococcus and aspergillus which was seen from the 2^nd day and heaviest on the 4^th 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 shelflife of locally brewed sorghum beer.

TABLE OF CONTENT

TITLE PAGE.i

CERTIFICATION....ii

DEDICATION............iii

ACKNOWLEDGEMENTS.iv

ABSTRACT..........v

TABLE OF CONTENTS........vi

LIST OF TABLESxiii

LIST OF FIGURES...xiv

CHAPTER ONE

1.0 INTRODUCTION. 1

1.1 AIMS AND OBJECTIVES2

CHAPTER TWO

2.0 LITERATURE REVIEW 4

2.1 GENERAL DESCRIPTION OF CEREALS... 4

2.1.1 GENERAL CHARACTERISTICS OF CEREALS4

2.2 SORGHUM..5

2.2.1 GENERAL DESCRIPTION OF SORGHUM.. 6

2.2.2 SCIENTIFIC CLASSIFICATION OF SORGHUM.7

2.2.3 GRAIN COMPOSITION AND NUTRITIVE VALUE7

2.2.4 CULTIVATION AND USES9

2.3 MILLET..10

2.3.1 GENERAL DESCRIPTION OF MILLET. 10

2.3.2 BOTANICAL CLASSIFICATION OF MILLET...11

2.3.3 PEST AND DISEASES OF MILLET.11

2.3.4 USES OF MILLET..12

2.4 BREWING..13

2.4.1 HISTORY OF BREWING..13

2.4.2 BREWING PROCESSES14

2.4.2.1 EUROPEAN BREWING PROCESS...14

2.4.2.2 INDIGENOUS AFRICAN BREWING PROCESS.17

2.5 RAW MATERIALS FOR BREWING...18

2.5.1 STARCH SOURCE.18

2.5.2 ADJUNCTS.19

2.5.3 WATER...19

2.5.4 HOPS...20

2.5.4.1 CHARACTERISTICS OF HOPS.21

2.5.4.2 TROPICAL HOP SUBTITUTES FOR BEER BREWING.22

2.5.5 YEAST25

2.5.5.1 BAKERS YEAST...25

2.5.5.2 BREWERS YEAST26

2.6 BIOCHEMISTRY OF BREWING PROCESSES..26

2.6.1 MALTING AND KILNING26

2.6.2 MILLING....27

2.6.3 MASHING...27

2.6.4 SOURING29

2.6.5 WORT BOILING29

2.6.6 FERMENTATION..31

2.6.6.1 ALCOHOL FERMENTATION...35

2.6.6.2 TOP FERMENTATION..36

2.6.6.3 BOTTOM FERMENTATION.37

2.6.7 PACKAGING37

2.7 SPOILAGE38

2.7.1 MICROORGANISM THAT DETERIORATE BEER...38

2.8 TYPES OF BEER...38

2.8.1 EUROPEAN BEERS...38

2.8.2 INDIGENOUS AFRICAN BEERS40

2.9 EFFECTS OF ALCOHOL ON MAN45

2.9.1 ALCOHOL AND HEALTH45

CHAPTER THREE

3.0 MATERIALS AND METHODS...47

3.1 MATERIALS.47

3.1.1 CHEMICALS AND REAGENTS..47

3.1.2 GLASSWARES AND EQUIPMENT48

3.1.3 PREPARATION OF SAMPLES50

3.2 METHODS50

3.2.1 METHOD OF PREPARATION OF SORGHUM BEER..50

3.2.2 ACTIVATION OF YEAST51

3.2.3 PREPARATION OF BITTERLEAF EXTRACT.51

3.2.4 PREPARATION OF REAGENT...52

3.2.4.11 PHENOLPHTHALEIN..52

3.2.4.2 0.1M NaOH SOLUTION.52

3.3 METHOD OF CHEMICAL ANALYSIS..52

3.3.1 TOTAL ACIDITY..52

3.3.2 FIXED ACIDITY53

3.3.3 VOLATILE ACIDITY53

3.3.4 PH DETERMINATION..53

3.3.5 SPECIFIC GRAVITY.53

3.3.6 TOTAL DISSOLVED SOLID54

3.3.7 TOTAL SUSPENDED SOLIDS.54

3.3.8 ETHANOL CONTENT..55

3.3.9 MICROBIAL COUNT55

3.3.9.1 PROCEDURES FOR THE PREPARATION OF MEDIA..55

3.3.9.2 PROCEDURE FOR CULTURING PLATES..56

3.3.9.3 PROCEDURE FOR IDENTIFICATION OF ORGANISMS..57

CHAPTER FOUR

4.0 RESULTS58

4.1 RESULTS FOR TOTAL ACIDITY, FXED ACIDITY, VOLATILE ACIDITY AND PH OF SORGHUM BEER.58

4.2THE GRAPHICAL REPRESENTATION OF TOTAL ACIDITY, FIXED ACIDITY, VOLATILEACIDITY AND PH RESULT ..58

4.3 RESULTS FOR ETHANOL CONTENT, SPECIFIC GRAVITY, TDS AND TSS FOR SORGHUM BEER...59

4.4 GRAPHICAL REPRESENTATION OF ETHANOL CONTENT, SPECIFIC GRAVITY, TOTAL DISSOLVED SOLIDS TDS AND TOTAL SUSPENDED SOLID TDS RESULTS 60

4.5 AVERAGE MEAN PARAMETERS GENERATED FROM HOPPED AND UNHOPPED SORGHUM BEER61

4.6 GRAPHICAL REPRESENTATION OF THE AVERAGE PARAMETERS GENERATED FROM SORGHUM BEER WITH AND WITHOUT HOPS.61

4.7 MICROBIAL COUNT FOR BENCH STORED SORGHUM BEER WITH AND WITHOUT HOP62

CHAPTER FIVE

5.0 DISCUSSION64

5.1 CONCLUSION.67

5.2 RECOMMENDATION68

REFERENCES ..69

APPENDIX A.74

APPENDIX B ..78

APPENDIX C..79