EFFECT OF GINGER AND GARLIC ON THE MICROBIAL LOAD AND SHELF-LIFE OF ZOBO DRINK (Hibiscus sabdariffa)

ABSTRACTZobo drink is a non-alcoholic beverage which is consumed in most part of Nigeria, mostly in the northern part of Nigeria It is produced from the dried calyces of the Roselle plant Hibiscus Sabdariffa(Malvaceae)by boiling and filtration. Microbial and sensory attribute of Zobo drink treated with ginger and garlic was investigated. Zobo drink was produced by hot extraction and filtration. The drink obtained was treated with different quantities of ginger and garlic and their effects evaluated during the period of 4 days of storage. A five- fold serial dilution of both treated and control drink samples were carried out for enumeration of microorganisms on appropriate media. The sensory evaluation of the samples was determined using standard methods. Different values of bacterial and fungal counts of both treated and control Zobo drink samples were obtained during the period of monitoring but the total viable bacterial count ranged from 4.11 x 106 – 3.62 x 107 cfu/ml while the fungal count ranged from 4.0 x 106– 3.59 x 107cfu/ml. Similarly, different values of the sensory evaluation of Zobo samples were obtained during the storage period. However, the samples containing ginger and/or mixture of both were better rated in terms of the parameter tested. Shelf-life (based on sensory overall acceptability) of the samples varied with the treatments. The ginger-treated sample showed to extend the shelf-life by 1 day whereas other treated samples showed marginal enhanced shelf-life of 3days. However, untreated control sample exhibited remarkably high microbial loads than the treated samples.
TABLE OF CONTENTSCertification ﾿ iDedication ﾿ iiAcknowledgements ﾿ iiiTable of Contents ﾿ ivList of Tables ﾿ viList of Figures ﾿ viiAbstract ﾿ viiiCHAPTER ONE1.0Introduction ﾿ 11.1 ﾿ Aim and objectives of the research ﾿ 2 ﾿ CHAPTER TWO2.0 ﾿ Literature review ﾿ 32.1 ﾿ Nutritive values ﾿ 52.2 ﾿ Economic values ﾿ 62.3 ﾿ Properties of garlic and ginger ﾿ 6 ﾿ CHAPTER THREE3.0 ﾿ Materials and methods ﾿ 93.1 ﾿ Collections of samples ﾿ 93.2 ﾿ Preparation of Zobodrinks ﾿ 93.3 ﾿ Treatment of the Zobodrinks with ginger and garlic ﾿ 93.4 ﾿ Microbiological analysis of samples ﾿ 103.5 ﾿ Enumeration and characterization of bacteria and fungi ﾿ 103.5.1 ﾿ Microscopic examination ﾿ 103.5.2 ﾿ Gram staining ﾿ 103.5.3 ﾿ Biochemical tests ﾿ 123.5.3.1 ﾿ Catalase test ﾿ 113.5.3.2 ﾿ Coagulase test ﾿ 123.5.3.3Indole test ﾿ 123.5.3.4 Citrate utilization test ﾿ 123.6 ﾿ Motility test ﾿ 133.7 ﾿ Sensory evaluations ﾿ 13 ﾿ CHAPTER FOUR4.0 ﾿ Results ﾿ 14 ﾿ CHAPTER FIVE5.0 ﾿ Discussions ﾿ 205.1 ﾿ Conclusions ﾿ 215.2 ﾿ Recommendations ﾿ 22 ﾿ References ﾿ 23 ﾿ Appendix I ﾿ 30 ﾿ Appendix II ﾿ 31 ﾿ Appendix III ﾿ 32