Grape cell wall polysaccharides influence the extraction of phenolic compounds during winemaking and consequently polyphenol concentrations in the final wine. During ripening, both compound groups undergo pronounced structural and compositional changes, resulting in a dynamic change of extractability. Grape cell wall polysaccharides from different ripe grapes were added to fermentations of Cabernet Sauvignon and Pinot noir grapes. Polyphenol-polysaccharide interactions affected the concentrations of tannins and monomeric flavanols in the wines depending on the maturity of the added polysaccharides. With higher polysaccharide maturity, the effects became more pronounced. Polysaccharides protected monomeric flavanols and tannin in Pinot noir, thereby increasing the concentrations, but they precipitated or masked these compounds in Cabernet Sauvignon. The added polysaccharides affected the concentrations in anthocyanins and polymeric pigments much less compared to the ripening status of the grapes. It was concluded that structural changes of polysaccharides during ripening affect the extraction of tannins and monomeric flavanols the most.
Keywords: Cabernet Sauvignon; Pinot noir; anthocyanins; extractability; grape cell wall polysaccharides; polymeric pigments; tannins; winemaking.