Study on the removal of anti-nutritional factors in bean dregs by solid-state fermentation

Bean dregs were the main by-product in the processing of soybean products and were an excellent source of animal feed. However, their large-scale application was restricted by anti-nutritional factors. The most harmful of anti-nutritional factors in bean dregs were trypsin inhibitors and antigen proteins. In order to remove trypsin isnhibitors and antigenic proteins in bean dregs, the fermentation process was optimized by single-factor experiments and the response surface methodology. The optimal fermentation process was as follows: inoculation amount was 10.5%, water content of fermentation medium was 58%, fermentation temperature was 35 degrees C, and fermentation time was 13 days. Under this fermentation process, the removal rate of trypsin inhibitors was significantly increased to 84.98%. SDS-PAGE showed that the antigenic proteins were completely degraded. Isothiocyanate was removed from 1.8 mg/100g to 0.48 mg/100g. Cellulose and hemicellulose were degraded from 23% and 22.35% to 20.02% and 15.2% respectively. The content of trichloroacetic acid soluble protein was greatly increased from 11.48% to 39.47%. The fermentation process improves the nutritional value of bean dregs and provides a good reference for the development of bean dregs biological feed