Abstract:Moringa seed meal (MSM) is the residual product after oil extraction from Moringa oleifera seed. Multi-strain solid-state fermentation (MSSF) has good stability and can improve the nutritional value and functional characteristics of MSM, making it potential for the preparation of antioxidant peptides and active high-protein foods. In this study, four microbial strains were used for the primary screening of MSM through plate diffusion assay and the secondary screening through mixed-culture fermentation, in order to screened out the most suitable fermentation microbial strains. The fermentation conditions were optimized through single-factor experiment and response surface experiment, the physicochemical characteristics, nutritional value, and functional characteristics of fermented moringa seed meal (FMSM) were analyzed. The results showed that the combination of Aspergillus oryzae and Bacillus licheniformis was the best fermentation strain. The optimal fermentation conditions were a fermentation time of 5.22 d, a solid-liquid ratio of 1 g:1.56 mL, a pH of 7.52, a temperature of 30 ℃, and an inoculum volume of 9%, yielding a maximum predicted degree of hydrolysis (DH) of 29.60%. Notably, compared to unfermented MSM, FMSM showed a significant increase in the content of nutrients such as crude protein, peptides, and total amino acids, while the content of crude fiber (CF), tannins, and phytic acid significantly reduced. Observation and analysis using scanning electron microscope(SEM) showed that MSSF destroyed the surface structure of MSM. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated the degradation of macromolecular proteins. By assessing the clearance rates of DPPH·, ABTS+·, and reducing power, it was demonstrated that MSSF could greatly improve the antioxidant activity of moringa seed meal.
