This report presents, first, the electrophilic nature of Q4MeC toward wines antioxidants and polyfunctional odoriferous desirable volatile thiols. 1H, 13C and 2D NMR analyses were used to identify the reaction products between 4-methyl-1,2-benzoquinone (Q-4MeC) and wine relevant nucleophiles like SO2, glutathione, ascorbic acid, phloroglucinol and a key odoriferous volatile thiol the 3-sulfanylhexanol. The formation of these reaction products was studied by HPLC-UV-MS, in wine like medium where the different nucleophiles were present in to two to four compounds mixtures. SO2, ascorbic acid and glutathione appear to provide a protection against 3SH consumption by the quinone, by acting as sacrificial nucleophiles. The antioxidant powers of SO2, AA and GSH were very similar and no antioxidant synergic effect was observed between these compounds when they tested in equimolar concentration.
Second we observed that the presence of carbonyl compounds in the matrix appear to decrease the SO2 antioxidant activity in a compound dependent manner. Acetaldehyde and pyruvate are very strong and fast SO2 binders, resulting in limited 3SH protection via their addition reaction with quinones. Ketoglutarate and galacturonate appeared less reactive with SO2, but their SO2 binding power needs further investigation under enological conditions. Finally, our NMR metabolomic approach of measuring the nucleophilic potential of wines reveled the importance of both SO2 and glutathione in controlling oxidation in wines, and opened new horizons for the development of powerful analytical tools for controlling oxidation during the vinification process and aging.