Characterization of volatile compounds between industrial closed fermentation and traditional open fermentation doubanjiang-meju

Doubanjiang-meju has been used as an intermediate for producing Pixian Douban (PXDB) and contributes significantly to its flavor. In this study, a profiling analysis of volatile compounds in open fermented doubanjiang-meju (OFD) and closed fermented doubanjiang-meju (CFD) was performed with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). A total of 42 and 50 volatile compounds were identified in the OFD and CFD, respectively. Compared with the OFD, more diversity and higher concentrations of alcohols and esters were found in the CFD. Ten and 12 volatile compounds were finally identified as the major aroma-active compounds in the OFD and CFD, respectively, by the combined analysis of aroma intensity values and odor activity values (OAVs). The CFD had significantly stronger umami and soy sauce flavor but weaker beany when compared with the OFD (p < 0.05) by quantitative descriptive analysis (QDA), which were basically consistent with intensity values of aroma compounds obtained with GC-O. The results indicated that the CFD had better characteristics of volatile compounds than those of the OFD, which provided a basis of further study for the closed fermentation process of tank fermenter.

Automated summary

The study found that closed fermented doubanjiang-meju has more diverse and higher concentrations of volatile compounds compared to open fermented doubanjiang-meju, with stronger umami and soy sauce flavors. This provides a basis for further research on the closed fermentation process of tank fermenter.