Application of UHPLC-Q/TOF-MS-based metabolomics in the evaluation of metabolites and taste quality of Chinese fish sauce (Yu-lu) during fermentation

Spontaneous fermentation is a critical step in the processing of high-quality fish sauce. In this study, a comparative UHPLC-Q/TOF-MS-based metabolomics approach combining equivalent-quantification and the taste activity value (TAV) was used, for the first time, to evaluate the taste qualities and characterize metabolite profiles in Chinese fish sauce during fermentation. A total of 22,816 metabolite ion features were extracted from fish sauce samples. Forty-six metabolites, including amino acids, small peptides, organic acids, amines, carbohydrates, and nucleic acids, were identified as key chemical components of fish sauce. In addition, absolute quantification and TAV showed that aspartic acid and glutamic acid exert an important influence on the umami taste of fish sauce. Specific metabolites were primarily associated with amino acid metabolism, particularly alterations in arginine and proline metabolism. This study identifies chemical components and provides novel insights into the taste quality of fish sauce due to fermentation.