Physical, chemical and microbiological changes during natural fermentation of \"gowé\", a sprouted or non sprouted sorghum beverage from West-Africa

Abstract

Gowé is a traditional Beninese fermented beverage prepared from sprouted and non- prouted cereals. Due to urbanization, a new technique without any malting step has appeared in Southern Benin and is now widely used. The two techniques were compared using sorghum as the raw material. The physical, chemical and microbiological changes that occurred during a 72 h fermentation period were studied in both techniques. The dominant microflora was a mixed population of lactic acid bacteria and yeasts. The lactic acid bacteria population was higher in the traditional product at the start of fermentation (6.1 log cfu/g wet basis versus 4.5 in the modified process) because of the malting step. It then increased to 9.3 log cfu/g after 48 h fermentation. Enterobacteriaceae counts increased slightly during the first stage of fermentation but fell below the detectable level after 24 h in the traditional raw gowé and after 48 h in the modified raw gowé. The pH decreased from 6.3 to 3.4 in the traditional process and from 6.6 to 3.8 in the modified process, while the titratable acidity increased from 0.4 to 6.4% (w/w, lactic acid) and from 0.4 to 4.2%, respectively. Total soluble and reducing sugar content first increased, and then decreased with a concomitant increase in organic acids. The major organic acids were lactic acid and acetic acid. The fermentation process was thus more intense and faster in the traditional process, giving a significantly lower level of crude fat.

African Journal of Biotechnology Vol. 4 (6), pp. 487-496, 2005