The fermentation characteristics of single and mixed yeast cultures during Pito wort fermentation

Abstract

Pito is an alcoholic beverage obtained through yeast fermentation of the wort extracted from sorghum malt. The production methods are largely artisanal and the product quality varies from batch to batch even for the same brewer. The use of starter culture is a plausible approach to minimizing the variability in product quality. This work compared the fermentation profile of single yeast and mixed yeast cultures in sorghum wort fermentation during pito production. A 2×3 factorial design was used to study the quality characteristics of wort pitched with single and mixed Culture yeast strains during 24, 48 and 72 hours alcoholic fermentation. The physicochemical properties, microbial load and sensory characteristics of samples were determined. Fermentation time had significant effects (p<0.05) on the pito characteristics. Pito color (of 12.5 and 16.5 EBC units) was different for single and mixed cultures respectively. Panelists perceived the colours of pito obtained from single yeast culture fermentation to be different from that obtained from mixed culture fermentation. Volatile aroma compounds identified during the fermentation period included esters (4), aldehydes (3), organic acids (2), alcohols (3) and a diacetyl. Both single and mixed cultures showed similar characteristics during wort fermentation.