Optimization of the sorghum malting process for pito production in Ghana

Abstract

Pito is an alcoholic beverage obtained through a yeast (Saccharomyces cerevisiae) fermentation of wort extracted from sorghum (Sorghum bicolor L. Moench) malt. The malting conditions of sorghum are thought to influence the quality characteristics of the malt, and subsequently the quality of the pito obtained from it. Studies were carried out on a local sorghum cultivar grown in Ghana - chireh, to optimize the conditions for malting conditions for pito production in Ghana. A 33 full factorial experimental design was replicated with steeping times of 12, 16 and 22h, germination times of 3, 4 and 5days, and malt drying temperatures of 30, 40 and 50°C as factors. Diastatic power, extract yield, attenuation limit and free amino nitrogen were determined. Germination duration significantly affected diastatic power and free amino nitrogen (p<0.001). Extract yield was also significantly influenced by germination duration (p=0.001). The germination time, steeping time and drying temperature had no significant effect on the attenuation limit. The optimal conditions for malting this specific cultivar grown in Ghana to obtain critical malt quality indices are 12.0-12.5h steeping, 5days of germination at 30°C and drying at 40°C. Free amino nitrogen levels in all treatments were higher than the minimum requirement for good yeast nutrition and fermentation.