THE USE OF UTAZI LEAF EXTRACT (GONGRONEMA LATIFOLIUM) AS A MEANS OF EXTENDING THE SHELF LIFE OF A LOCALLY BREWED SORGHUM BEER
ABSTRACT
Sorghum beer is an indigenous African alcoholic beverage that has been long traditionally brewed in the Savannah region of Nigeria; over the years there has been a problem with the Keep ability of these beers. Contemporally, a conceptual approach of hopping these beers with an indigenous hop extracts; Utazi (Gongronema latifolium) has relatively improved its chemical properties compared to the Unhopped beer. This has been proven from the following; appreciable decrease in its ethanol content, total acidity, volatile acidity, Aspergillus prevalence from the fourth day of its bench storage relative to the Unhopped beer which manifested in the second day. This clearly shows that the hopped sorghum beer with Utazi has a decreased rate of deterioration compared to the conventional Unhopped counterpart.
TABLE OF CONTENTS
Title page = = = i
Certification page = = = ii
Dedication = = = iii
Acknowledgement = = = iv
List of figures = = = v
List of tables = = = vi
Table of contents = = = vii-xi
Abstract = = = xii
CHAPTER ONE = = = 1
1.0 Introduction = = = 1-2
1.2 Aims and objectives = = 2
CHAPTER TWO = = = 3
2.0 Literature review = = 3
2.1 Historical overview = = 3-4
2.2 Brewing of Beer = = 5
2.2.1 Contemporal Western Brewing Process = 5-7
2.2.2 Indigenous African brewing process = = 7-8
2.3 Raw materials for brewing = = 8-9
2.3.1 Starch Source = = 9-10
2.3.2 Water = = 10
2.3.3 Hops = = 11
2.3.3.1 Hop substitutes = = 12
2.3.3.2 Utazi (Gongronema latifolium). = = 12-13
2.3.3.3 Chemical properties of ‘Utazi’ = = 13-14
2.3.4 Brewer’s yeast = = 13-15
2.3.5 Baker’s yeast = = 15
2.4 Biochemistry and microbiology of
Brewing and malting= = = 16
2.4.1 Malting and kilning = = 16
2.4.2 Miling and mashing = = 16
2.4.3 Chemistry of mashing = = 17
2.4.4 Souring = = 17
2.4.5 Boiling = = 17-18
2.4.6 Straining = = 18
2.4.7 Alcoholic fermentation = = 18-19
2.4.8 Aging , Filtering and Package = = 19
2.4.9 Spoilage = = 20
2.4.91 Beer spoilage organisms = = 20-22
2.5 Chemistry of fermentation process = = 22-25
2.5.1 Alcoholic fermentation process = = 26-27
2.6 Types of beers = = 27
2.6. 1 European types = = 27-28
2.6.2 Indigenous African beers = = 28
2.6.2.1 Classification of fermented AfricanBeers = 29
2.6.2.2 Pito = = 30
2.6.2.3 Merissa = = 30-31
2.6.2.4 Bouza = = 31-32
2.7 Local production of Burukutu = = 33-34
2.7.1 Nature of its malting process = = 34
2.8 Some indigenous African non alcoholicbeverages = 35
2.8.1 Ogi = = = 36
2.8.2 Banku = = = 36
2.9 Cereals = = = 37
2.9.1 Millet = = = 38
2.9.1.2 Scientific classification = = = 38-39
2.9.1.1.3 Current uses of millet = = = 39-40
2.9.1.1.4 Other uses of millet = = = 40-41
2.9.2 Sorghum = = = 41-42
2.9.2.1 Scientific classification = = = 42
2.9.2.2 Uses of sorghum = = = 43-44
CHAPTER THREE = = = 45
3.0 Materials and method = = = 45
3.1 Materials = = = 45
3.1.1 Chemicals and reagents = = = 45
3.1.2 Glasswares and equipments = = 45-47
3.2 Preparation of samples===47
3.2.1 Methods = = = 47
3.2.2 Ingredients = = = 47
3.2.3 Methods of preparation = = 47-48
3.2.4 Activation of yeast = = 48
3.2.5 Preparation of Utazi leaf extracts = = 48
3.2.6 Preparation of reagents = = 49
3.2.6.11% phenolphthalein = = 49
3.2.6.2 0.1m NaoH = = 49
3.3 Method of Chemical Analysis = = 49
3.3.1 Total Acidity = = 49
3.3.2 Fixed Acidity = = 50
3.3.3 Volatile Acidity = = 50
3.3.4 pH Determination = = 50
3.3.5 Specific Gravity = = 51
3.3.6 Total dissolved Solids (TDS) = = 51
3.3.7 Total suspended Solids (TSS) = = 51-52
3.3.8 Ethanol Contents = = 52
3.3.9 Microbial Count = = 52-53
3.3.9.1 Procedures for the preparation theof media = 53
3.3.9.2 Procedures for culturing plates = = 54
3.3.9.3 Procedures for the identification of Organisms = 54
CHAPTER FOUR = = 55
4.0 Results = = 55
4.1 Parameters generated from Hopped and
Unhopped sorghum Beers with (G. latifolium) = = 58
4.2 Specific gravity of bench stored Sorghum Beer
Hopped with Utazi (G. latifolim) and withoutHops=56
4.3 Total Acidity of bench stored Sorghum Beer
Hopped with Utazi (G. latifolium) and withoutHops = 57
4.4 Ethanol content of bench stored Sorghum Beer
Hopped with Utazi (G. latifolium) and withoutHops = 58
4.5 Microbial count of bench stored Sorghum
Beer with Hops Utazi (G. latifolium) = 59
4.6 Microbial count of bench stored Sorghum
Beer without Hops Utazi (G. latifolium) = 59
CHAPTER FIVE = = 60
5.0 Discussion and conclusion. = = 60
5.1 Discussion of Results = = 60-65
5.2 Conclusion = = 65-66
5.3 Recommendations = = 66
References = = 67-69
Appendix = = 70-72
CHAPTER ONE
1.0 INTRODUCTION:
Beer is an alcoholic beverage made from cereal grains, usually barley, but also corn, sorghum, millet, rice, wheat, and oats. Beer is made using a process called fermentation, in which microscopic fungi called yeast consume sugars in the grain, converting them to alcohol and carbon dioxide gas (Michael,et al, 2004). Over 70 styles of beer are available today. Each style derives its unique characteristics from its ingredients and subtle differences in its brewing process (Gunsch, 2010). Throughout history, wherever cereal grains were grown, humans made a beerlike beverage from them: they used wheat in Mesopotamia, Barley in Egypt, Millet and Sorghum in other parts of Africa, rice in Asia, and corn in the Americas. Today, beer making is a major industry worldwide (Dornbush, et al, 2006).
Our indigenous African Beers are sourced fermented drinks made with Sorghum, Maize or Millet. ‘Pito’ is a dark brown traditional alcoholic beverage of Binis in the western part of Nigeria prepared from malted grains (Maize, Sorghum or both) with a pleasant sour taste (Ekundayo, et al,1969). ‘Burukutu’ another indigenous alcoholic drink made from sorghum,Savannah region of Nigeria (Uveve, et al, 200)The production process of both drinks involvesfermentation at its initial production stage and comes out as an alcoholic drink. Other locally made deetrinks include; ‘KunuZaki’, ‘Bouza,’ ‘Merissa’, ‘Komoni’ and Bogule. The shelf life of these drinks isaffected by their method of preparation, storage methods and the presence of a hop extracts in them (Morcos, et al, 1973).
Some of our locally sourced tropical hop extracts include Bitter leaf extracts (Vernon iaamygdalina ), Utazi leaf extracts (Gongronemalatifolium) both leaves have been found to contain an Anti-bactericidal agent which is capable of extending the useful life of these indigenous beers (Uveve, et al, 2002). Freezing and cooling are another different ways of preservation using low temperature. Freezing involves the changing of liquid to solid which can occur between the 0.5Image to 3Image temperature ranges. Chilling which is a level of freezing involves making something cool especially using a refrigerator. Such things could be referred to as ‘refrigerated’. Chilling can occur between 0Image to 5Image. These conditions help to preserve the quality by prolonging the life our indigenous drinks. (Dog fish Head Craft Brewery, 2010).
1.2 AIMS AND OBJECTIVE
(i) To determine the shelf life of a locally brewed Sorghum Beer.
(ii) To check the effect of ‘Utazi’ leaf extract on the shelf life of the locally brewed Sorghum Beer.
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