Partial enzymolysis affects the digestion of tamarind seed polysaccharides in vitro: Degradation accelerates and gut microbiota regulates

Two hydrolyzed fractions of tamarind seed polysaccharide (TSP), denoted ETSP1 (176.68 kDa) and ETSP2 (34.34 kDa), were prepared by partial degradation via endo- xyloglucanase, and then characterized and evaluated by simulated gastrointestinal digestion in vitro . The results showed that the hydrolyzed TSPs remained indigestible in gastric and small intestinal media, and were fermented by gut microbiota, similar to the native TSP (M w  = 481.52 kDa). Although the degradation of hydrolyzed TSPs was accelerated during fermentation with a decreasing degree of polymerization, the content of produced total short-chain fatty acids (SCFAs) decreased. After fermentation, the gut microbiota composition was modified, esp. the Firmicutes/Bacteroidetes ratio decreased (1.06 vs. 0.96 vs. 0.80) with a decreasing degree of polymerization, which implied that the potential anti-obesity prebiotic effect was enhanced. At the genus level, hydrolyzed TSPs maintained similar roles as native TSP, including promoting beneficial bacteria ( Bifidobacterium , Parabacteroides , and Faecalibacterium ) and inhibiting enteropathogenic bacteria ( Escherichia-Shigella and Dorea ). Moreover, ETSP1 had additional potential due to abundant Bacteroides vulgatus (LDA = 4.68), and ETSP2 might perform better as related to Bacteroides xylanisolvens (LDA = 4.40). All these results indicated the prebiotic potential of hydrolyzed TSP with detailed information about changes in degradation and gut microbiota based on enzyme-hydrolysis.