Umami peptide identification and interaction dynamics in traditional fermented Seabass: Bridging sensory evaluation with molecular insights

Traditional fermented sea bass is an Asian product known for its abundant umami peptides. We successfully isolated and characterized FDD (Phe-Asp-Asp), EDEI (Glu-Asp-Glu-Ile), GIELE (Gly-Ile-Glu-Leu-Glu), and ELPDGQ (Glu-Leu-Pro-Asp-Gly-Gln) from fermented sea bass using an aqueous extraction method, followed by purification and identification techniques, such as UF (ultrafiltration), GFC (gel filtration chromatography) and RP-HPLC-MS. Sensory evaluations and e-tongue analyses validated the enhancement of umami, salty, and sweet flavors in the chicken broth. Sigmoid curves revealed a synergistic effect of ELPDGQ and EDEI, whereas FDD and GIELE exhibited an additive effect in a solution of 1 mg/mL MSG. We employed molecular docking to investigate the interactions with T1R1/T1R3 receptors, highlighting the roles of Ser, His, Ala, Gly, and Glu, as well as considering aspects like hydrogen bonding, aromatic interactions, hydrophilicity, and the solvent-accessible surface area. Additionally, molecular dynamics simulations confirmed the stability of the peptide-receptor complexes. This study lays a theoretical foundation for the extraction of umami peptides from fermented marine fish and provides an understanding of the perception of these peptides. Future studies should focus on improving the umami intensity of synthetic umami peptides by modifying their spatial conformation, and further exploring the umami taste mechanism of the umami peptides and how these peptides can be synthesized on a large scale. • Four novel umami enhancing peptides were identified from fermentation sea bass. • Taste thresholds of FDD, EDEI, GIELE, and ELPDGQ ranged from to 0.0391-0.0938 mg/mL. • Umami enhancing shown as synergistic effect (ELPDGQ and EDEI) and additive effect (FDD and GIELE). • The stability of peptides-umami receptors complexes was validated by molecular dynamics simulation.