Production of Traditional Sorghum Beer “Ikigage” Using Saccharomyces cerevisae, Lactobacillus fermentum and Issatckenkia orientalis as Starter Cultures

摘要

This study was carried out to evaluate the potential of the use of predominant yeast strains (Sacharomyces cerevisiae and Issatkenkia orientalis) and lactic acid bacteria (Lactobacillus fermentum) of Rwandese traditional sorghum beer “ikigage” as starter cultures to improve ikigage beer. The results show that L. fermentum has an influence on taste sour of ikigage beer and contributes also to generating ethyl acetate, ethyl lactate and higher alcohols such as 3-methylbutan-1-ol, 2-me- thylbutan-1-ol and 2-methylpropan-1-ol of this beer. I. orientalis contributed to the production of ethyl butyrate, ethyl caprylate, isobutyl butyrate and their corresponding acids, and to the generation of phenyl alcohols in ikigage beer. The association of S. cerevisiae with I. orientalis and L. fermentum produced ikigage beer with taste, aroma and mouth feel more similar to ikigage beers brewed locally by peasants. It is recommended to use S. cerevisiae in association with L. fermentum and I. orientalis as stater cultures to produce ikigage beer having the uniform organoleptic characteristics and a high ethanol content. This method also reduces the risk of contamination of the brew with food sanitary indicator and pathogenic microorganisms and will increase the chance of preservation of ikigage beer.