Fractionation, preliminary structural characterization and prebiotic activity of polysaccharide from the thin stillage of distilled alcoholic beverage

Thin stillage is the distillery stillage from distilled alcoholic beverage, which has great economic potential. In this study, a novel polysaccharide from the thin stillage of distilled alcoholic beverage (CRWP1) was purified with a molecular weight of 8554 Da. CRWP1 was mainly composed of glucose, galactose , mannose , and glucuronic acid at approximate percentages of 91.56, 2.13, 1.61 and 1.84, respectively. The structural chain of CRWP1 consisted of (1→4)-linked -Glcp, (1→)-linked-Glcp, (1→3,6)-linked-Manp, (1→6)-linked-Galp, (1→6)-linked-Glcp and contained with α and β glycosidic bonds by fourier transform infrared spectroscopy (FTIR), methylation and nuclear magnetic resonance (NMR) analysis. Following 48 h of fecal fermentation in a bionic gastrointestinal reactor, CRWP1 could promote the relative abundance of Bacteroides , Bifidobacterium , and Collinsella at the genus level, as well as the production of short-chain fatty acids (SCFAs). Furthermore, CRWP1 fermentation increased production of organic acids (especially butyric and oleic acids) and polyols (such as 1,3-propanediol). This is the first report on the prebiotic potential of CRWP1 and it provides a foundation for the potential application in economical food industry.