<i>Tremella sanguinea</i> polysaccharides: DES–UAE extraction, structural features, and <i>in vitro</i> digestion–fermentation

This study investigated the optimized extraction, characterization, and fermentation properties of Tremella sanguinea polysaccharides (TSP), achieving a yield of 36.59% via a deep eutectic solvent ultrasonic-assisted method. Structural analysis identified TSP as a high-molecular-weight (~325 kDa) acidic heteropolysaccharide, composed mainly of mannose, xylose, glucuronic acid, and glucose. TSP exhibited resistance to simulated gastrointestinal digestion, indicating promising potential for colonic delivery. During 24-hour fecal fermentation, TSP, similar to other tested Tremella polysaccharides, promoted Lactobacillus and suppressed Fusobacterium. Concurrently, TSP also enriched Escherichia – Shigella and Klebsiella while reducing Bacteroides and Bifidobacterium. These findings underscore the complex microbiota-modulating effects of TSP. In conclusion, this study presents an efficient method for preparing TSP, highlighting its structural and functional properties, including gut microbiota modulation. These findings lay the groundwork for its potential application in functional foods, pending in vivo safety and efficacy validation.