Structural and digestive characters of a heteropolysaccharide fraction from tea (Camellia sinensis L.) flower

Tea (Camellia sinensis L.) flower polysaccharides (TFPS) have various health-promoting functions. In the present work, the structure of a purified TFPS fraction, namely TFPS-1-3p, and its in vitro digestive properties were investigated. The results demonstrated that TFPS-1-3p was a typical heteropolysaccharide consisting of rhamnose (Rha), arabinose (Ara), galactose (Gal) and galacturonic acid (GalA) with a molecular weight of 47.77 kDa. The backbone of TFPS-1-3p contained → 4)-α-d-GalpA(-6-OMe)-(1 → 4)-α-GalpA-(1 → and → 4)-α-d-GalpA(-6-OMe)-(1 → 2,4)-α-l-Rhap-(1 → linkages. The branch linkages in TFPS-1-3p contained → 6)-β-d-Galp-(1→, →3,6)-β-d-Galp-(1→, →5)-α-l-Araf-(1 → and → 3,5)-α-l-Araf-(1 →. Subsequently, TFPS-1-3p could not be degraded under simulated human gastrointestinal conditions but could be of use to human fecal microbes, thereby lowering the pH and increasing the production of short-chain fatty acids (SCFAs) of the gut microenvironment and altering the composition of the gut microbiota. The relative abundance of Fusobacterium_mortiferum Megasphaera_elsdenii_DSM_20460, Bacteroides thetaiotaomicron, Bacteroides plebeius and Collinsella aerofaciens increased significantly, potentially contributing to the degradation of TFPS-1-3p.