Abstract: In order to explore the relationship between metabolites and the quality of fumigated vinegar, the metabolite dynamics during the traditional brewing process of Liangzhou fumigated vinegar were studied. In situ samples of fermented grains at the end of 1st, 3rd, 5th, 8th, 12th and 17th of fermentation from a certain production line were determined for their 9 major physicochemical properties related to the microbial metabolism. The changes in the physicochemical properties and the mutual relationships among them were explored. Meanwhile, hierarchical cluster analysis was employed to divide the brewing process. During the brewing process, the temperature and the contents of reducing sugar and alcohol in fermented grains increased at the beginning and then stepped down. The contents of starch and protein decreased till the end of the brewing process. The acidity and amino acid content increased during the whole process, but the moisture content basically did not change throughout the fermentation process. The brewing process was divided into two stages, with the first stage including days 1, 3 and 5, while the second stage days 8, 12 and 17. The result of hierarchical cluster analysis accorded with the actual composition of the brewing process. Consistency and delay were showed between the technological and metabolic levels.

Key words: Liangzhou fumigated vinegar, metabolite, dynamics, correlation analysis, hierarchical cluster analysis