Contribution of Several Volatile Phenols and Their Glycoconjugates to Smoke-Related Sensory Properties of Red Wine

Abstract

Guaiacol and 4-methylguaiacol are well-known as contributors to the flavor of wines made from smoke-affected grapes, but there are other volatile phenols commonly found in smoke from forest fires that are also potentially important. The relationships between the concentration of a range of volatile phenols and their glycoconjugates with the sensory characteristics of wines and model wines were investigated. Modeling of the attribute ratings from a sensory descriptive analysis of smoke-affected wines with their chemical composition indicated the concentrations of guaiacol, <i>o</i>-cresol, <i>m</i>-cresol, and <i>p</i>-cresol were related to smoky attributes. The best-estimate odor thresholds of these compounds were determined in red wine, together with the flavor threshold of guaiacol. Guaiacol β-d-glucoside and <i>m</i>-cresol β-d-glucoside in model wine were found to give rise to a <i>smoky/ashy</i> flavor in-mouth, and the respective free volatiles were released. The study indicated that a combination of volatile phenols and their glycosides produces an undesirable smoke flavor in affected wines. The observation of flavor generation from nonvolatile glycoconjugates in-mouth has potentially important implications