Taste properties and mechanism of umami peptides from bay scallop (

This research investigated the extraction and functional characterization of novel umami peptides from bay scallop by-products and explored the molecular basis of their flavor-enhancing effects. The by-products were subjected to sequential enzymatic hydrolysis using alkaline protease AP200-A and flavor protease FF106, followed by multistep purification. Sensory testing revealed that fraction F2 exhibited the strongest umami intensity. Peptide identification using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) led to the detection of 65 potential umami peptides. Virtual screening subsequently identified three promising candidates: HELPRY, WDGRDGAVD, and AHELPRYG. Sensory evaluation and electronic tongue analysis demonstrated that all three synthetic peptides exhibited significant umami intensity and umami-enhancing effects, with detection thresholds ranging from 0.10 to 0.51 mmol/L and enhancement thresholds from 0.08 to 0.41 mmol/L. Notably, the detection thresholds were relatively low. To elucidate the molecular mechanism underlying their taste, molecular docking and dynamics simulations were performed. The results showed that all three peptides formed stable complexes with the umami receptor T1R1/T1R3, with hydrogen bonding as the primary driving force. Key binding residues, including ASN150, SER158, LYS155, ASP219, PRO57, and ARG255, played critical roles in receptor recognition. Molecular docking and dynamics simulations confirmed stable binding to T1R1/T1R3, with binding energies ranging from -9.353 to -8.476 kcal/mol, and hydrogen bonding was identified as the predominant interaction. This study provides novel umami peptides from a sustainable source and elucidates their interaction mechanism with the taste receptor, offering a theoretical basis for the high-value application of shellfish by-products in the flavoring industry.