Difference Analysis of Volatile Sulfur-Containing Compounds in 6 Kinds of Wuling Soy Sauce Aroma-Type Baijiu

Volatile sulfur-containing compounds (VSCs) have the characteristics of intensive aromas and low thresholds, which have important impacts on the flavor of foods. However, concentrations of most VSCs in food are below the detection limit of gas chromatography-mass spectrometry (GC-MS), which are difficult to be identified and recognized. Soy sauce aroma-type is a main aroma-type of Baijiu in China, Wuling soy sauce aroma-type Baijiu, which produced in Hunan, is one of important representatives. In order to further explore the composition of important trace VSCs in soy sauce aroma-type Baijiu in China, head space solid phase micro-extraction combined with comprehensive two-dimensional gas chromatography-sulfur chemiluminescence detector (GC×GC-SCD) was used in this study to analyze the VSCs in 6 kinds of Wuling soy sauce aroma-type Baijiu samples. A total of 27 VSCs were identified in this study, of which 19 VSCs were coexistent and 8 VSCs were not coexistent in 6 kinds of Wuling soy sauce aroma-type Baijiu samples, mainly including 4 kinds of thiols, 6 kinds of thioesters, 5 kinds of thioethers, 5 kinds of thiazoles, 6 kinds of thiophenes and 1 kind of thiane. The external standard curve method was used for quantitative analysis of 23 VSCs of which signal to noise ratio was greater than 100. Based on quantitative analysis results, principal component analysis and orthogonal partial least squares discriminant analysis were used to demonstrate the differences in the VSCs contents of 6 kinds of Wuling soy sauce aroma-type Baijiu samples. Fourteen VSCs with variable projection value greater than 1 were screened out as the difference components to distinguish the flavor characteristics of the 6 kinds of Wuling soy sauce aroma-type Baijiu samples. It was hoped that the study could provide data reference for the blending of soy sauce aroma-type Baijiu and provide help for Baijiu enterprises to regulate the production process and improve product quality.