Dynamic changes in physico-chemical attributes and volatile compounds during fermentation of Zhenjiang vinegars made with glutinous and non-glutinous japonica rice

The characteristics of Chinese brewed vinegars are influenced by the different raw materials, microbial environment, and special brewing technology. For the first time, this study analyzed and compared the physicochemical properties changes and volatile composition throughout the whole process at different stages of two kinds of vinegars, which were fermented under the traditional production process of Zhenjiang aromatic vinegar with glutinous rice (ZAV) and non-glutinous japonica rice (RV). Other important parameters, such as sugar composition and levels of amino acids and organic acids, were also considered. ZAV and RV differ in their saccharification, alcohol fermentation, acetic acid fermentation, and decoction stages, whereas some similarities emerge in the later stages. Compared to RV, ZAV contains more abundant constituents and rich aroma compounds, which account for their product features and flavor differences. Results of this research may provide guidance for improving the production technology, flavor quality, and food safety of Chinese traditional vinegar.