Abstract:Three components with the strongest umami flavor, namely E-4, F-8, and F-8a, were identified in oyster sauce using fractional solvent extraction and column chromatography combined with comprehensive human sensory evaluation. Using an Orbitrap Exploris 480 mass spectrometer coupled to an EASY-nanoLC 1200 system, 6,820 peptides were identified through database searches and de novo sequencing. Among them, 24 were potential umami peptides. After validation, 12 umami peptides are confirmed, with nine being novel characteristic umami peptides specific to oyster sauce. The sequences of the 12 umami peptides are as follows: SKGGV, TTGK, MTTTT, TTRQ, SGTT, LGTT, TTCCHL, ATSI, IGTT, TTAL, GSTT, and TTPL. The binding interactions of the peptides with the homology model of T1R1/T1R3 primarily involved ionic interactions, electrostatic interactions, hydrophobic interactions, and salt bridges. Key binding sites included Arg108, Arg220, Asp219, Asp129, Glu148, Glu217, and Lys155. Additionally, the umami peptide SKGGV exhibited the highest "-CDOCKER_ENERGY" value of 89.9746, indicating that SKGGV has the strongest umami-enhancing effect. Furthermore, sensory evaluation revealed that the sourness and sweetness of each isolated component were positively correlated with umami, whereas the aroma of cooked oysters, medicinal flavor, and caramel flavor were associated with the umami taste. This study provides insights for subsequent research on the umami mechanism and establishes a theoretical basis for the development and utilization of umami peptides in oyster sauce.
