The influence of polyphenols on the hydrolysis and formation of volatile esters in wines during aging: An insight of kinetic equilibrium reaction.

The evolution of volatile esters leads to changes in wine aroma during aging. In this study, polyphenol effect on ester equilibrium in wines was investigated through three aging experiments. Kinetic parameters of esters were calculated in four red wines. Results showed that the reaction rate constant (k) was mainly determined by the molar concentration ratio of alcohols or acids to the corresponding esters. Phenolic matrix was more likely to influence the activation energy (E). Higher contents of total polyphenol led to the increase of E, resulting in the reactions less prone to happen but more susceptible to temperature changes. Combined with the practical wine aging and exogenous polyphenol addition experiments, the impact of polyphenol composition was revealed. Flavanols with higher polymerization degrees were found more beneficial for ester preservation than monomer flavanols or anthocyanins. This work could provide theoretical guidance in enhancing fruity aroma in wines via modulating phenolic matrix.