Characterization of Aroma Compounds in Chinese Rice Wine Qu by Solvent-Assisted Flavor Evaporation and Headspace Solid-Phase Microextraction

The aroma of Chinese rice wine Qu is one of the most important factors that influences the flavor of Chinese rice wine. To better understand the aroma of Qu, aroma compounds in four wheat Qus and two xiao Qus were identified by chromatography−olfactometry (GC-O) after solvent extraction followed by solvent-assisted flavor evaporation (SAFE). A total of 39 aroma compounds were characterized by GC-O. On the basis of aroma intensity, 1-hexanal, ethyl hexanoate, 1-octen-3-ol, and phenylacetaldehyde were found to be the most important aroma compounds in all six Qus. In addition, 3-methylbutanol and 2-phenylethanol also played an important role in the aroma of two xiao Qus. Headspace solid-phase microextraction (HS-SPME) was used for quantifying aroma compounds identified in the Qus. The method enabled limits of detection and quantification of <40.8 and <136.0 μg/L, respectively. Linearity and recovery were satisfied in all cases. Quantitative analysis revealed that volatiles of six Qus had a wide range of concentration. Principal component analysis applied to the data differentiated the six Qus well.