White wine lees as a source of antioxidants: Insights into their chemical profile

White wine lees are known to enhance the oxidative stability of white wine, but the complete set of compounds responsible for this property remain unidentified. Furthermore, due to matrix variability, the studies on the overall composition of lees are not exhaustive. In order to bring new insights, phytochemical constituents of 41 white wine lees samples were characterised, including tartaric acid, lipids, proteins, polysaccharides, polyphenols, and total sulfhydryl compounds. Targeted quantification of polyphenols (phenolic acids, flavanols, flavonols, stilbenoids) and glutathione was performed using UHPLC-HRMS, and correlated with measured antiradical activity (DPPH method). Results revealed significant variability in composition and antioxidant capacity among lees. Correlation analysis showed positive impact of polyphenols, particularly hydroxycinnamic acids, and total sulfhydryl compounds on antioxidant potential. The absence of correlation with glutathione suggests that other sulfhydryl compounds may contribute to antiradical activity. These findings offer valuable insights into the bioactivity and antioxidant potential of white wine lees.