Characterization of the volatile profile of Chinese rice wine by comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry

BACKGROUND Chinese rice wine (CRW) is a kind of traditional fermentation wine in China. Aged CRW is more popular among consumers owing to its harmonious and pleasant flavor. The volatile profile of CRW has been extensively studied using gas chromatography/mass spectrometry (GC/MS). However, flavor components in CRW are far richer than those detected by GC/MS. To obtain more information about the volatile profile of fresh (5-year) and aged (10-year) CRW, a method based on comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GCxGC/qMS) was developed. The major volatile compounds contributing to the characteristic aroma of fresh and aged CRW were identified by surrogate odor activity value (OAV). RESULTS Ninety-eight volatile compounds were detected in the 5-year CRW samples and 107 in the 10-year samples by GCxGC/qMS. The numbers of compounds detected by GCxGC/qMS for the 5-year and 10-year samples were 71.4 and 65.4% higher than those detected by GC/MS. The aged wine had a more complex volatile profile than the fresh wine, with an increase in esters and aldehydes and a decrease in alcohols and organic acids. There were 22 volatile compounds with surrogate OAV > 1. Nine were the potent key aroma compounds in CRW: ethyl isovalerate (OAV 500-33 500), ethyl butyrate (OAV 84-334), ethyl isobutyrate (OAV 49-170), 2-nonenal (OAV 20-100), ethyl heptanoate (OAV 1-74), ethyl hexanoate (OAV 60-77), phenylethyl alcohol (OAV 2-18), benzaldehyde (OAV 28-30) and hexanal (OAV 4-11). CONCLUSION GCxGC/qMS showed better separation than GC/MS. The presented GCxGC/qMS method was suitable for characterization of the volatile profile of CRW. (c) 2019 Society of Chemical Industry