Taste characteristics and umami mechanism of novel umami peptides and umami-enhancing peptides isolated from the hydrolysates of Sanhuang Chicken

This study identified umami and umami-enhancing peptides, which explain the umami taste of Sanhuang chicken. Ten novel peptides were isolated from chicken hydrolysate by gel filtration chromatography and reverse-phase high-performance liquid chromatography. The amino acid sequence was analyzed by UPLC-Q-Exactive Orbitrap-MS: HGEDKEGE, IPIPATKT, SEASNNK, IGPGLGR, AGDDAPR, FAGDDAPR, ADGLWL, KDGGGGK, PGPAGPAGP, and GFLGPQ. All synthetic peptides were discovered with umami and umami-enhancing effects based on the sensory evaluation and electronic tongue. Of these, HGEDKEGE, and SEASNNK showed a prominent umami taste, and the umami threshold values of the umami peptide were 0.56 and 0.33 mmol/L, respectively. The AGDDAPR and IGPGLGR had better a umami-enhancing effect. The molecular docking results confirmed that all peptides entered the Venus flytrap (VFT) domain of T1R3, new binding sites were obtained, Arg303, Ser123, and His121 might play critical roles in the umami-enhancing effects. Residues of Ser146 and Ser123 were found to play decisive roles in umami taste.