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Structural characterization and in vitro fermentation of a novel polysaccharide from Sargassum thunbergii and its impact on gut microbiota

Fu, Xiong, Cao, Changliang, Ren, Beibei, Zhang, Bin, Huang, Qiang, Li, Chao
Carbohydrate polymers 2018 v.183 pp. 230-239
Sargassum thunbergii, arabinose, digestive system, fermentation, functional foods, galactose, glucose, inoculum, intestinal microorganisms, mannose, molecular weight, pH, polysaccharides, valeric acid, xylose
The aim of the present study was to investigate structural characteristic and in vitro fermentation of a novel polysaccharide named ST-P2 from Sargassum thunbergii by human fecal inoculums, and its impact on human colonic microbiota. The results showed that ST-P2 was homogeneous with molecular weight of 48,788 Da, and consisted of arabinose, galactose, glucose, xylose, and mannose. The main linkage types were identified as (1 → 5)-α-L-Araf, (1 → 3)-α-L-Manp, (1 → 3,6)-β-D-Galp, (1 → 6)-α-D-Glcp, and (1 → 3)-β-D-Xylp, respectively. After 48 h fermentation, 67.83 ± 1.15% of total carbohydrate was utilized by colonic microbiota. The pH value in the fecal culture significantly decreased from 6.09 ± 0.11 to 4.70 ± 0.04. The concentrations of total short chain fatty acids, acetic, propionic, n-butyric and n-valeric acids significantly increased compared to the blank. ST-P2 could remarkably modulate the composition and abundance of beneficial microbiota. These results suggest that ST-P2 could potentially be a functional food aimed at promoting the gut health.