Abstract:In this study, we analyzed the qualities of fish sauce, fish soy sauce and light soy sauce using the electronic nose. An electronic nose captured the flavors of light soy sauce, fish sauce and fish soy sauce, and the information was assessed with principal component analysis (PCA), linear discriminant analysis (LDA) and loadings analysis. The qualities of the sauces were then determined with the results above together with factors such as amino acid nitrogen, total nitrogen, salinity and the content of free amino acids. The results showed that fish sauce and light soy sauce were first-class products, and that fish soy sauce was a super product. There were a variety of free amino acids in the three sauces. The contents of threonine, glycine, alanine, methionine and lysine in fish sauce were higher than those in fish soy sauce and light soy sauce. The content of flavor amino acids in light soy sauce and fish soy sauce was significantly higher than that in fish sauce. This was because sodium glutamate was added into fish soy sauce and light soy sauce, but there was no added substance in fish sauce. However, the content of essential amino acids in light soy sauce was the lowest. The flavors in the light soy sauce, fish sauce and fish soy sauce were complex. The electronic nose responded differently to the three kinds of sauce, and the ten sensors of the electronic nose could distinguish the flavors in fish sauce, fish soy sauce and light soy sauce. Sensors W5S, W1S and W2S had a relatively higher resistivity than others, and the W2S sensor played an important role in recognizing the first and the second principal components. These enabled the electronic nose to identify light soy sauce, fish sauce and fish soy sauce .The first and the second principal components were the same in all three sauces, but the contribution rate of ethanol and nitrogen oxides was different to the first and to the second principal components.
