Decoding the molecular basis for temperature control by metabolomics to improve the taste quality of soy sauce fermented in winter

Abstract

This study aimed to explore the material basis of the temperature-controlled fermentation method (30 °C) to improve the taste quality of soy sauce fermented in winter under 200 tons industrial scale by quantitative description analysis (QDA), physicochemical and metabolomic analysis. Results showed that the taste of soy sauce fermented at controlled temperature (SSCT) was superior to that of soy sauce fermented at room temperature (SSRT), especially the intensity of umami, kokumi, and sweet. The contents of total nitrogen and amino acid nitrogen in SSCT were significantly higher. 49 non-volatile compounds (13 organic acids, 10 sugars, 9 sugar alcohols, 15 amino acids and 2 others) were identified by GC-MS derivatization, classified according to the taste characteristics and taste active value (TAV) was calculated. The total TAV of sweet and umami substances increased while the total TAVs of sour substances decreased for SSCT. Moreover, out of the 191 peptides/amino acids derivates detected by UPLC-MS/MS, where 34 compounds had large differences. Some umami compounds (Fru-Glu, Fru-Val and Fru-pGlu) and kokumi compounds (γ-Glu-Leu, γ-Glu-Ile) were significantly higher in SSCT. These results revealed the intrinsic reasons for the improved quality of temperature-controlled soy sauce and provided a theoretical basis for the exploration and industrial application of temperature control on soy sauce fermentation.