Effects of acetylated polysaccharide on the prebiotic properties of grape seed proanthocyanidins – Based on in vitro fermentation with Artemisia sphaerocephala Krasch glucomannan

This study evaluated the impact of Artemisia sphaerocephala Krasch glucomannan with different degrees of acetyl group substitution (DS) on the prebiotic properties of grape seed proanthocyanidins (GSP). UV spectra, CIELab, and dynamic light scattering analyses indicated DS-influenced variable interactions between GSP and glucomannan. In vitro fermentation demonstrated that glucomannan enhanced the solubility of some phenolic compounds, and decreased the pH value of fermentation liquids. The production of acetate acid and total short chain fatty acids in the GSP fermentation liquid increased with the degree of DS of glucomannan. Notably, acetylated glucomannan exerted dramatic effects on GSP-induced gut microbiota modulation. The relative abundances of Bacteroides ovatus and Bacteroides decreased as DS increased. Meanwhile, Bacteroides acidifaciens and Akkermansia muciniphila have a positive correlation, even though the GSP-promoted enrichment of A. muciniphila was inhibited by the added glucomannan. Moreover, glucomannan enhanced the metabolism of nucleotides, secondary bile acid, and glycan inhibited by GSP. These findings suggest that acetylated glucomannan affect the prebiotic properties of GSP with its DS serving as a key factor.