Dynamic changes in volatile aroma compounds during Chinese Xiaoqu Baijiu brewing

Baijiu aroma has become an increasingly popular topic in the study of aroma compounds. However, the changes in the volatile aroma compounds of Chinese Xiaoqu Baijiu during the brewing process remain unclear. In this study, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to analyze the flavor components throughout the brewing process of Chinese Xiaoqu Baijiu. A total of 208 volatile compounds were identified, which were categorized into 18 groups, including carboxylic acids and derivatives (25 %), organic acids and derivatives (17.8 %), benzene and substituted derivatives (13 %), alcohols and amines (10.6 %), among others. Among these compounds, 91 and 93 volatile aroma compounds were specifically induced during the saccharification and fermentation stages, respectively, while 176 volatile compounds were reduced and 104 volatile compounds remained in the base Baijiu following distillation. The content of volatile aroma compounds was significantly lower in base Baijiu than during other stages, with fewer esters detected in base Baijiu. These results provide valuable information to further improve methods aimed toward increasing the content of volatile aroma compounds in Baijiu.