Interaction of Flavors with Polyphenols Compounds Found In Wine

Research to date has focused on validating a gas chromatographic headspace method for measuring the volatility of flavor compounds in solution. Using this procedure with model odorant compounds, we monitored the time course for obtaining equilibrium between the gas and liquid phases and observed that equilibrium times of greater than 30 minutes were needed to obtain accurate measurements of headspace concentration. The method is sensitive allowing the measurement of the concentration of odorants in the gas phase above aqueous solutions containing <2 ppm odorant. The model odorants are generally found in foods and wine at levels above this concentration. Coefficients of variability for replicate analyses were less than 10%indicating good reproducibility. Using this method we have shown that catechin, a major wine polyphenol, significantly depressed the headspace concentration of ethyl benzoate in aqueous solution. These findings provide evidence for an association between catechin and ethyl benzoate which results in decreased ethyl benzoate volatility. However, catechin had no significant effect on the headspace concentration of n-butylpropionate, indicating that there is no interaction between the flavonoid and the unsaturated ester.