Improvement of the protein quality and degradation of allergens in soybean meal by combination fermentation and enzymatic hydrolysis

In this study, we determined the effect of short-time fermentation-assisted enzymatic hydrolysis on the improvement of protein quality and reduction of potential antigenicity in soybean meal (SM). SM was fermented by using Lactobacillus plantarum, Lactobacillus casei, Bacillus subtilis, Bacillus licheniformis, or Aspergillus oryzae for 24 h, and then, each of the fermented SM was hydrolyzed with Alcalase for 15 min. The color, SDS-PAGE, degree of hydrolysis, molecular weight distribution, and amino acid profile of SM were evaluated. In addition, the potential antigenicity of SM was also assessed by ELISA. Results showed that fermentation-assisted with Alcalase hydrolysis could effectively decrease the antigenicity of β-conglycinin and glycinin in SM, exhibited higher degree of hydrolysis and loss of intensities in several major bands, especially those of α′ and α subunits of β-conglycinin and acidic subunit of glycinin, as indicated by SDS-PAGE. Increased peptide (<10 kDa) content was observed in the final fermented soybean meal. Simultaneously, most of the total amino acid increased significantly (p < 0.05) and only few of them suffered a decrease depending on the type of microorganisms. It was also found that Bacillus subtilis could be more favorable than other microorganisms for developing hypoallergenic soybean products.