Studies on the Interactions of Flavor Compounds with Nonvolatile
Flavor and aroma are important factors in influencing food and beverage (i.e., wine) choices. However, knowledge of flavor concentration alone is not sufficient to determine the perceived sensory aroma intensity. This is due to the presence of interactions between flavors and nonvolatile food components which can alter flavor volatility and release. We used NMR techniques to study the mechanisms of binding between flavor compounds and polyphenols, the main nonvolatile constituents of wine. Our results showed that the interactions are dependent on the structure of both the flavor compounds and the polyphenols. The interactions are principally due to hydrophobic interactions between the aromatic rings of the flavors and the polyphenols. However hydrogen-bonding effects help to stabilize the complex and enhance the specificity. By understanding the mechanisms of these interactions and their effects on flavor perception we will be better able to optimize grape and wine composition and winemaking procedures to improve wine flavor. This proposal is a continuation of a previously funded project. During previous years we focused on developing analytical methods (Gas Chromatographic and NMR) and sensory procedures for measuring odorant interactions in model solutions (Objective b and c). Results have been published (Mialon and Ebeler, 1997) and presented at national meetings of the ASEV (June 1996 & June 1998). An oral presentation outlining recent progress was presented at the National Meeting of the American Chemical Society in New Orleans, LA in August, 1999. A manuscript has been accepted for publication as a result of this research.