Simulated Gastrointestinal Digestion and In Vitro Fecal Fermentation of Purified Pyracantha fortuneana (Maxim.) Li Fruit Pectin

<i>Pyracantha fortuneana</i>, an underutilized wild plant, has been found to have a high nutritional value. This study used simulated digestion and fecal fermentation models to investigate the digestive properties of the purified acidic pectin polysaccharide of <i>Pyracantha fortuneana</i> and its impact on the gut microbiota and metabolites. <i>Pyracantha fortuneana</i> polysaccharide (PFP) is mainly composed of rhamnose (Rha), galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara), with a molecular weight (Mw) of 851.25 kDa. Following simulated digestion, the Mw of PFP remained consistent. The reduced sugar content showed minimal change, suggesting that PFP exhibits resistance to gastrointestinal digestion and can effectively reach the colon. Following fecal fermentation, the molecular weight, monosaccharide, and carbohydrate contents of PFP decreased, while the short-chain fatty acid content increased. This suggests that PFP is susceptible to degradation by microorganisms and can be metabolized into acetic acid and <i>n</i>-butyric acid, contributing to the regulation of intestinal health. Meanwhile, PFP promotes the reproduction of beneficial bacteria such as <i>Bacteroides</i>, <i>Dialister</i>, and <i>Dysgonomonas</i>, inhibits the growth of harmful bacteria like <i>Proteus</i>, and generates metabolites such as thiamine, leonuriside A, oxoadipic acid, S-hydroxymethylglutathione, and isonicotinic acid, which exert beneficial effects on human health. These results indicate that PFP has great potential in regulating the gut microbiota and generating beneficial metabolites to promote intestinal functional health and can be used as a prebiotic to prevent diseases by improving intestinal health.