Characteristics of polysacchadride from Psoralea corylifolia in simulated gastrointestinal digestion and microbial fermentation

• PPs were not degraded during simulated digestion in vitro . • PPs were utilized by the intestinal microbiota during fermentation. • Revealing the interaction between PPs and intestinal microbiota. Psoralea corylifolia polysaccharide (PPs) was the bioactive ingredient that conferred health benefits. In this study, simulated digestion and anaerobic fermentation models were employed to explore the digestion and fermentation characteristics of PPs and its effect on the intestinal microbiota. The results revealed that while the total and reducing sugar contents of PPs increased after simulated digestion, their molecular weight, monosaccharide composition, and overall structure remained unchanged, indicating that PPs was not degraded during digestion. On the other hand, during anaerobic fermentation, PPs was metabolized by intestinal microbiota, leading to the production of acetic acid and propionic acid, which subsequently reduced the pH of the fecal culture solution. Additionally, PPs modulated the composition of the intestinal flora, significantly decreasing the relative abundance of Proteobacteria while increasing the relative abundance of Bacteroidota and Firmicutes to varying degrees. This study highlighted the potential of PPs for development as functional foods and therapeutic agents.