Wine polysaccharides influence tannin-protein interactions

Tannins are responsible for the astringency of red wine where it is considered to be the perception that follows tannin interaction with salivary protein. In this study, the influence of red wine polysaccharides on the interactions between tannins and proteins has been investigated. The mean degree of polymerization, subunit composition and molecular mass of tannins was determined for tannins isolated from various red wines. In addition, the composition of total soluble polysaccharides was determined for polysaccharides isolated from the same red wines. The influence of polysaccharides on the interaction between tannins and protein were investigated. The ability of tannins to interact with a hydrophobic surface (tannin activity) did not significantly change after the addition of the corresponding polysaccharides. Rhamnogalacturonan II, the proportion of pigmented tannins and the mean degree of polymerization seemed to encourage protein precipitation either through the formation of insoluble tannin-polysaccharide aggregates or because of protein-polysaccharide interactions. (C) 2016 Elsevier Ltd. All rights reserved.