In Vitro Digestion and Fermentation Characteristics of Cordyceps militaris Mycelial Polysaccharide and Its Regulatory Effects on the Intestinal Environment

Cordyceps militaris mycelial polysaccharides (IPS) possess diverse metabolic and bioactive properties, yet existing studies on their gastrointestinal digestion and prebiotic potential remain scarce. This study aims to investigate the changes of IPS at different digestive stages and its interactions with the gut microbiota. During simulated salivary digestion, no significant changes were observed in IPS. During simulated gastric digestion, the reducing sugar content of IPS significantly increased, while in simulated intestinal digestion, this value decreased. After in vitro fermentation, the total carbohydrate, reducing sugar levels, and pH of digested IPS declined to different extents. Microbiome profiling demonstrated that IPS markedly elevated the relative abundance of Firmicutes, whereas it suppressed the levels of Proteobacteria, especially the pathogenic genus Shigella. Furthermore, total short-chain fatty acids (SCFAs) increased from 0.77 mmol/L to 3.58 mmol/L after 24 h fermentation. Collectively, these results verify that IPS holds great potential to improve intestinal homeostasis and alleviate gut-related disorders.