Abstract
Grape seed powders (GSP) have demonstrated the ability of preventing protein instability in wine by pre-emptive precipitation. Condensed tannins, an important component of grape seeds, are well-known protein binders, and allow this powder to be used for protein stabilization. This ability of GSP is usually enhanced by roasting treatment, which causes the heavier fractions to be broken down into smaller oligomers. We present the characterization of extractable condensed tannins in grape seed powders according to the degree of polymerization (DP from 2 to 10) for seeds of the cultivars Sangiovese, Croatina, and Ortrugo. Roasting of the seeds caused higher abundances of almost all DP, despite the overall effect was cultivar-dependent. Grape seed powder from the grape cultivars Croatina and Sangiovese showed increasing condensed tannins for almost all DP upon roasting. The white cultivar Ortrugo did not show clear effects upon roasting.