Dynamic changes of structural characteristics of snow chrysanthemum polysaccharides during in vitro digestion and fecal fermentation and related impacts on gut microbiota

The in vitro simulated saliva-gastrointestinal digestion and human fecal fermentation of snow chrysanthemum polysaccharides (JHP) were investigated. Results showed that reducing sugar contents of JHP increased during the gastrointestinal digestion, and glucose released with the decrease of its molecular weight, suggesting that JHP could be partially degraded under the gastrointestinal digestion. Furthermore, after in vitro fecal fermentation, the molecular weight and molar ratio of constituent monosaccharides (galactose and galacturonic acid) of the indigestible JHP (JHP-I) significantly decreased, and both monosaccharides and oligosaccharides released, suggesting that JHP-I could be further degraded and consumed by gut microbiota. Some beneficial bacteria, such as genera Bifidobacterium, Lactobacillus, Megamonas, and Megasphaera, significantly increased, suggesting that JHP-I could change the composition and abundance of gut microbiota. These results suggest that JHP is a potential source of prebiotics, and can be helpful for better understanding of the potential digestion and fermentation mechanism of JHP.