Effect of combined germination and spontaneous fermentation on the bioactive, mineral, and microbial profile of red sorghum and pearl millet flours

Abstract

The aim of the study was to evaluate the influence of combined germination and spontaneous fermentation on the phytochemical, mineral, and microbial profile of red sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R.Br.) flours. The analysis of the studied flours were performed by molecular spectrophotometry and flame atomic absorption spectrophotometry, respectively. Bioavailability of the iron, zinc, and calcium was estimated using the phytates/minerals molar ratios. The microbial load was counted using culture media specific to total bacteria, lactic acid bacteria, yeast and moulds, and Gram-negative bacteria. Combined processing resulted in flours exhibiting the lowest (p ˂ 0.05) total phenols, flavonoids, 3-deoxy-anthocyanidins, phytates contents, and DPPH scavenging activity and the highest (p ˂ 0.05) ABTS inhibition, mineral contents, and bioavailable iron, zinc, and calcium contents. Combined processing also resulted in the highest (p ˂ 0.05) microbial cell counts, with lactic acid bacteria being the most abundant species in both processed cereals. Combining germination and spontaneous fermentation of red sorghum and pearl millet flours could be a useful and simple processing technique to develop food products that alleviate mineral deficiencies and promote human health.