Oxidation of glycerol in the presence of hydrogen peroxide and iron in model solutions and wine. Potential effects on wine color

Abstract

Wine oxidation appears to include the formation of hydroxyl radical (center dot OH), an exceptionally reactive and thus nonselective compound that might be involved in the production of important aldehydes and ketones. This experiment examined the center dot OH oxidation of glycerol, a major wine constituent, and thus a likely target of such oxidation, in model wine, generated by hydrogen peroxide and iron catalysis. The oxidation products generated were analyzed as their hydrazones using LC-DAD/MS. Glyceraldehyde and dihydroxyacetone were the main compounds identified, both of which were also observed in naturally aged and center dot OH-oxidized wines. As anticipated, the presence of ethanol in the model wine did not preclude the formation of these compounds. Additionally, when a young red wine was treated with these oxidation derivatives, a noteworthy increase in color was observed, most likely due to the formation of novel anthocyanin-based structures.