Characterization and Identification of Yeast Peptides Released during Model Wine Fermentation and Lees Contact

Aging wine on lees results in the release of different yeast components, including peptides, whose role in wine is unclear. In this study, peptides released in a synthetic must, fermented with an oenological yeast strain, and aged on lees for 180 days were quantified (RP-HPLC) and identified (LC-MS/MS) at different time points. A rapid increase in peptide concentration was observed in the first two months, with over 2600 sequences identified. During the following four months, the peptide concentration remained constant, while their variety decreased slightly, probably due to enzymatic hydrolysis to which longer and less charged sequences were more exposed. The majority of the most abundant peptides were present over the 6-month period. They mostly originated from proteins associated with glycolysis and with different stress-response mechanisms, and they showed different in silico bioactivities. These findings can contribute to understanding the role of yeast peptides in regulating the wine environment during aging.