Transformation effects of Bacillus subtilis BSNK-5 on okara: Insights into its component transformation, structural characteristics, and functional properties

The high-value utilization of okara is vital for promoting sustainable practices in the soybean industry and addressing global food security challenges. This study investigated the effects of Bacillus subtilis BSNK-5 fermentation on okara's nutritional, structural, and functional properties. BSNK-5 fermentation effectively degraded insoluble dietary fiber, protein, and fat into soluble fiber, peptides, amino acids, and fatty acids, while reducing trypsin inhibitors and antigenic proteins. It also increased phenolic compounds, promoted the conversion of glycosides to aglycones, and enhanced digestibility and nutritional quality. After fermentation with BSNK-5, the surface wrinkles of the okara were reduced, and the particles became smaller. Additionally, BSNK-5 fermentation improved water-holding, oil-holding, swelling capacities, antioxidant activity, cholesterol binding, glucose absorption, and antihypertensive properties. These results highlight the potential of BSNK-5 fermentation to enhance okara's nutritional and functional value, providing valuable raw materials for the food industry.