Microbiological and chemical analysis of fermented sorghum dough for Kisra production

Summary

Sorghum flour was fermented in the traditional way for Kisra production. Wet or dry preparations of fermented sorghum dough from Sudanese households were employed as inocula. Microbiological and chemical analysis was performed throughout the fermentation process. Cell counts reached values of up to 9 × 10⁸ cfu/g and contained >99% lactobacilli. Strains of Lactobacillus fermentum, L. reuteri and L. amylovorus or L. fermentum and L. amylovorus were found as dominant organisms in doughs inoculated with wet or dry sorghum dough preparations, respectively. The ratios of the lactobacilli remained constant after up to four consecutive fermentations. After inoculation with the dry dough preparation the yeast Candida krusei was detected at 10⁶ cfu/g. During the fermentation the pH declined from 5.5 to values of approximately 3.4. The maltose content of the dough decreased continuously, wheraas glucose was accumulated as an intermediate. The relative content of most amino acids in the doughs did not significantly change during the fermentation. However, the concentrations of cysteine and methionine decreased, whereas threonine was enriched in the dough.