Effect of using glutathione-enriched inactive dry yeast preparations on the phenolic composition of rosé Grenache wines during winemaking

Aim: To know the effect of the addition of a commercial glutathione-enriched Inactive Dry Yeast (G-IDY) oenological preparation on the phenolic profile and colour parameters of rosé Grenache wines. Methods and results: A Control wine (Cont-W) and a wine with the G-IDY preparation (G-IDY-W) were industrially manufactured. The evolution of the phenolic composition (anthocyanins and non-anthocyanins) and colour of both types of wines was evaluated during winemaking and their shelf-life (after 1, 2, 3 and 9 months of bottle aging). Results revealed that wines manufactured with the G-IDY preparation showed differences in both their phenolic composition and colour characteristics with respect to the control wines, particularly after 9 months of aging. These differences were more evident in the anthocyanin than in the non-anthocyanin compounds. Conclusions: The G-IDY wines showed a greater decrease of the anthocyanins from grape origin, probably due to the formation of anthocyanin-polysaccharide complexes, and a higher concentration of some anthocyanin-derived pigments. These changes can be related to the slower colour evolution determined in wines produced using G-IDY preparations. Significance and impact of the study: The addition of the G-IDY preparation during winemaking modifies the anthocyanin composition of the resulting wines, which seems to provoke a slower colour evolution during their shelf-life