Abstract: The distillation process of baijiu is an enrichment process from Jiupei to raw baijiu, and is one of the most important processes in baijiu production. During the distillation process many substances produced during the solid-state fermentation are dissolved in liquid phase and become a part of raw baijiu. Among them, terpenes, phenols and pyrazines have not only contributed significantly to the flavor of baijiu, but also attracted lot of attentions because of their biological activities. Staged picking is used in the distillation process, and various volatile bioactive ingredients in the raw baijiu at different distillation stages may have certain differences. In this paper, two pretreatment methods, solid-phase microextraction (SPME) and vortex-assisted liquid-liquid microextraction (VA-LLME), are used to study the changes of volatile bioactive ingredients during distillation and found that VA-LLME is more suitable. According to the results, the content of pyrazines and most phenols in different fractions increased with the extension of distillation time, the content of ethyl linoleate decreased, and the contents of dimethyltrisulfide and 3,5-di-tert-butyl-4-hydroxybenzaldehyde did not change significantly during the distillation process. The experimental results show that some volatile bioactive ingredients can be generated by chemical reactions that occur during distillation, and the distilling rule of compounds is related to the structures of the compounds themselves.

Key words: vortex-assisted liquid-liquid microextraction(VA-LLME), baijiu, distillation, volatile bioactive ingredients, change rule