Impact of starter culture on nutraceutical and functional properties of underutilized millet-legume co-fermented Indian traditional product

Abstract

The influence of starter culture on finger millet-horse gram (cereal-legume) co-fermented Indian indigenous food product (dosa) on antioxidant and nutraceutical properties was investigated. Microbial consortium (Lactobacillus plantarum, Enterococcus faecalis and Saccharomyces cerevisiae) was used as starter inoculum. Controlled fermentation (8 h, 5% inoculum) enhanced the total phenolic content 1.5-fold which certainly associated with antioxidant activities. Significant (p < 0.05) increase in reducing power and free radical scavenging activities were observed in fermented batter and its corresponding product (dosa) compared to unfermented one. Caffeic acid, quercetin, gallic acid, p-coumaric acid, and syringic acid were detected as key phenolic acids in the product. Solubility of antioxidant compounds increased after in vitro gastrointestinal digestion for the dosa and attained good sensory score. Amino acid profile revealed 1.06-fold increase in the total essential amino acid and 21% rise in lysine content during controlled fermentation. Other essential amino acids viz. methionine, cysteine, histidine, isoleucine, valine, leucine and tryptophan also increased notably. Significant (p < 0.05) increase in extractable rate of minerals, protein and starch digestibility and decrease in phytate content were observed during fermentation. Thus, the controlled fermented product with significant nutrient content and antioxidant properties, and high acceptability would be used as a nutraceutical product.