Influence of Fining with Plant Proteins on Proanthocyanidin Composition of Red Wines

Chantal Maury; Pascale Sarni-Manchado; Sandrine Lefebvre; Veronique Cheynier; Michel Moutounet

Abstract

Protein fining treatments clarify wine and reduce astringency. Five plant protein preparations (two whole wheat glutens, two hydrolyzed wheat glutens, and one preparation from white lupin, Lupinus alba) were studied to evaluate their suitability as wine fining agents with regard to their capacity to precipitate condensed tannins. Fining of two wines and a model wine with these proteins showed that precipitation always occurred, although the level of precipitation was low. The hydrolyzed wheat glutens and the white lupin preparation were the most selective, precipitating highly polymerized and highly galloylated tannins, as did gelatin. Initial results showed that plant proteins can be used as fining agents in enology.

Acknowledgments: The authors thank G. Guiraud from Suber Œnologie (France) for providing the wines, Martin Vialatte for the plant proteins and gelisol, and Martine Pradal for amino acid determinations.