Comparison of Low-Salt Fish Sauce Prepared under Pressurized Carbon Dioxide with Commercial Fish Sauces

Abstract

　Fish sauce is prepared by fermentation with high salt concentrations to inhibit microbial growth. We applied pressurized carbon dioxide (pCO₂) to the fermentation process of fish sauce, and produced a low-salt fish sauce with an enhanced broth-like odor and a less putrefactive odor. We compared the pCO₂ fish sauce (10% NaCl concentration, 3 MPa CO₂, fermented at 30℃ for approximately 6 months) after heating at 100℃ for 10 min to commercial fish sauces (Yoshiru, Nampla, and Nouc-mam). No mesophilic bacteria were detected in the pCO₂ fish sauce, and the number of amine types detected in fish was also reduced. The free amino acid composition was similar to that of the Yoshiru. In addition, pCO₂ fish sauce had an increased broth-like odor with a suppressed fish-like odor compared to Nampula and Nuocmam. It also scored high on the overall impression of smell on the sensory test. These results show that the pCO₂ fish sauce has an improved odor and high quality compared to commercially available fish sauces prepared using the conventional method.