Differentiating Huangjiu with Varying Sugar Contents from Different Regions Based on Targeted Metabolomics Analyses of Volatile Carbonyl Compounds

Huangjiuis one of the oldest alcoholic beverages in the world. It is usually made by fermenting grains, and Qu is used as a saccharifying and fermenting agent. In this study, we identified differential carbonyl compounds inHuangjiuwith varying sugar contents from different regions. First, we developed and validated a detection method for volatile carbonyl compounds inHuangjiu, and for optimal extraction, 5 mL ofHuangjiuand 1.3 g/L of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) were incubated at 45 °C for 5 min before extracting the volatile carbonyl compounds at 45 °C for 35 min. Second, the targeted quantitative analysis of 50 carbonyl compounds inHuangjiushowed high levels of Strecker aldehydes and furans. Finally, orthogonal projections to latent structures discriminant analysis (OPLS-DA) was used to differentiate betweenHuangjiuwith different sugar contents, raw materials, and region of origin. A total of 19 differential carbonyl compounds (VIP > 1,p< 0.05) were found inHuangjiuwith different sugar contents (semidry and semisweetHuangjiu), and 20 differential carbonyl compounds (VIP > 1,p< 0.05) were found in different raw materials forHuangjiuproduction (rice and nonriceHuangjiu). A total of twenty-two and eight differential carbonyl compounds, with VIP > 1 andp< 0.05, were identified in semidry and semisweetHuangjiufrom different regions (Zhejiang, Jiangsu, Shanghai, and Fujian), respectively.Keywords:Huangjiu;carbonyl compounds;PFBHA;targeted metabolomics;OPLS-DA