Studies on the Interaction of Flavor Compounds with Nonvolatile Components of Wine

Objectives: We proposed to investigate the effects that polyphenols, important nonvolatile constituents of wine, have on the volatility and aroma intensity of selected aroma compounds through: a) use of model odorant compounds to provide a systematic exploration of the effect odorant structure has on interactions with polyphenols; b) application of sensitive gas chromatographic headspace procedures to measure changes in volatility of odorants in the presence of polyphenols; c) correlation of instrumental results with measurements of sensory intensity to understand the effect interactions may have on flavor perception, and utilization of NMR technology to provide an understanding of the mechanisms of polyphenol and odorant interactions. Summary: During previous years of this proposal we focused on developing sensitive gas chromatographic headspace procedures for quantifying odorant/polyphenol interactions in model solutions. We also developed and evaluated sensory procedures for measuring these interactions. Using a time-intensity procedure and model solutions, we showed that retronasal aroma perception is significantly affected by the chemical/physical nature of the aroma compound, by the nature of the matrix, and by individual judge factors such as salivary flow rate. This work was recently published (Mialon and Ebeler, 1997). During the past year we have largely focused on optimizing NMR techniques to study flavor odorant interactions. We have observed that the structure of both the polyphenol and the odorant are critical for determining the strength of the interaction.