LC-MS based metabolomics analysis of okara fermented by Bacillus subtilis DC-15: Insights into nutritional and functional profile.

Recent studies emphasize the improved nutritional and functional status of fermented okara; however, little is known about the metabolite change during fermentation and how it alters metabolic pathways. A metabolomics approach based on untargeted LC-MS reveals metabolic changes in okara fermented by Bacillus subtilis DC-15. We identified 761 differential metabolites, with the highest abundances found in amino acids, dipeptides, fatty acids, small molecule sugars, and vitamins. Moreover, these identified metabolites were mapped to their respective biosynthesis pathways in order to gain a better understanding of the biochemical reactions triggered by fermentation. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, 485 metabolites were enriched to metabolism-related pathways. They include 37 carbohydrate metabolites, 79 amino acid metabolites, and 22 lipid metabolites. As a result of okara fermentation, we observed a gradual enrichment of metabolites and stabilization of the compounds.