Salinity plays a dual role in broad bean paste-meju fermentation

Abstract

Chinese have learned to regulate salinity for broad bean paste-meju preparation over hundreds of years, yet the mechanisms of salinity in regulating the aroma and safety have not been identified. Here, we explored the effects of salt concentration (6%, 9%, 12%, and 15%, w/w) on the broad bean paste-meju fermentation. Results showed that low salt meju fermented rapidly, flavors such as OAs and FFAs were produced more quickly, and monosaccharides were consumed much more quickly by microorganisms. There was abundant linoleic acid, oleic acid, palmitic acid in fermented meju. Salt concentration resulted in an entirely different flavor of meju. Some acids and phenols compounds were prominent in the low salt group. Whereas the compounds that contributed to sauce aromas such as ethanol, hexadecanoic acid ethyl ester, and 4-ethyl-guaiacol were mainly detected in the high salt group. On the other hand, the low salt condition is beneficial for BAs production, contents of BAs in the 6% salt content broad bean paste-meju was much higher than in other groups (reached 2599.18 ± 725.75 mg/kg). In brief, salt plays an important role in broad bean paste-meju fermentation. Through this study, we would recommend 9%-12%, especially 12% as appropriate salt content for broad bean paste-meju fermentation.