Chemical and Electrochemical Assessment of Wine Lees Extracts Tested as Novel Antioxidant Additives in Model Wine

Yeast derivatives are used in winemaking for a variety of purposes, including the protection of wines from oxidation. In this work, by the application of an autoclave extraction method, different fractions were obtained from red wine lees and a lab grown culture of the same yeast strain. Each extract was characterized for their protein, polysaccharide, glutathione, thiol, and polyphenol contents. The antioxidant activity was tested by adding each extract in a model wine enriched with catechin and saturated with oxygen. The presence of both wine lees and lab-grown yeast extracts delayed oxygen consumption when compared to the untreated control. This delay was confirmed by the development of a yellow color, which was lower in 5 out of 6 of the samples added with yeast/lees extracts. The electrochemical behavior of the samples also showed a greater resistance to oxidation, thus suggesting a protective role of the wine lees extracts against wine oxidative phenomena.