Modified dietary fiber from soybean dregs by fermentation alleviated constipation in mice.

Soybean dregs are the main by-product obtained from the processing of soy products and are good sources of dietary fiber (DF). This study showed that the soluble DF content increased from 4.97% to 18.82%, while the insoluble DF content decreased from 59.37% to 44.89% after soybean dreg fermentation using Trichoderma spp., without any significant change in the total DF content (p > 0.05). Physicochemical property and electron microscopy analysis revealed that the rehydration ratio, dissolution rate, expansion force, and oil holding capacity of DF significantly increased (p < 0.05) with finer microstructure. Additionally, we found that fermented DF could further promote intestinal peristalsis in mice. Furthermore, fermented DF was more effective in balancing and adjusting intestinal flora in mice and promoting the production of short-chain fatty acids. Therefore, this study provides evidence indicating a correlation between the physicochemical properties and functional benefits of DF derived from soybean dregs.