Identification of the key odor-active compounds responsible for varietal smoky aroma in wines made from the East Asian species

A smoky aroma was found in wines made from East Asian species that had not been treated with oak products or exposed to smoke. In this study, a combined method of sensory analysis and quantitation of aroma compounds was used to identify the chemical basis of this smoky aroma. Syringol, eugenol, 4-ethylguaiacol, and 4-ethylphenol were confirmed as the key odor-active compounds contributing to the varietal smoky notes in wines of East Asian species. The concentrations of these compounds showed significant variation between grape species. The highest levels of syringol were found in Vitis amurensis wines, with an average of 178.8 μg/L. The average concentration of eugenol in V. davidii wines was 101.5 μg/L, about 10 times higher than in other species. 4-Ethylphenol and 4-ethylguaiacol were both abundant in the wines of the East Asian species. The results of the sensory interaction between the four compounds showed a complete addition effect for eugenol, a partial addition effect for syringol, and a hyper-addition effect for 4-ethylguaiacol and 4-ethylphenol on the smoky attribute.