Impact of alternative protein fining agents on the phenolic composition and color of Syrah red wines from warm climate.

Currently, the wine industry has an increasing interest in developing alternative solutions to traditional animal proteins fining agents. In this study, the impact of different protein fining agents on the turbidity, phenolic composition and color of 2-month and 12-month Syrah red wines was assessed. Wines fined with egg albumin and plant-based proteins from potato, pea, and grape seed as recent alternative, were compared to unfined control wines. Changes on turbidity, phenolic composition and color (by Differential Colorimetry) showed that animal and plant proteins differed in their clarifying efficiency and ability to interact with colorless phenolics and anthocyanins, depending on the age of wine, with important consequences on color quality and stability. Plant proteins showed lower effectiveness to reduce wine turbidity than egg albumin but modified in different way the phenolic composition, inducing lower color differences with respect to control wine and similar stability, especially potato and grape seed proteins.