Improvement of the Nutritional Quality of Rapeseed Meal through Solid-State Fermentation with B. subtilis, S. cerevisiae, and B. amyloliquefaciens

In this study, the effect of solid-state fermentation with Bacillus subtilis GYB6, Saccharomyces cerevisiae NJ1, and Bacillus amyloliquefaciens Y8 on the anti-nutritional factors, nutritional components, bioactive compounds, antioxidant activity, functional properties, and structure of rapeseed meal (RSM) were investigated. Results showed that the action of three strains in the fermentation of RSM caused a significant decline in glucosinolates, phytic acid, crude fiber, and tannins by 99.18%, 42.41%, 27.21%, and 34.17%, respectively. The amount of crude protein, amino acids, and peptides of RSM increased significantly after fermentation. The SDS-PAGE results showed that 12S globulin and 2S albumin protein were almost entirely degraded. Fermentation considerably increased the concentration of total phenolics and flavonoids, and activated antioxidant activity and functional properties. Furthermore, the structural variation was observed by scanning electron microscopy and FTIR spectroscopy. Thus, these results indicated that the solid-state fermentation process in this study was a promising approach to enhance both the nutritional value and bioactivity of RSM, which could be used as value-added functional animal food ingredients.