Excavation, Identification and Structure-Activity Relationship of Heat-Stable Umami Peptides in the Processing of Wuding Chicken

Umami peptides from different stages of Wuding chicken processing were discovered, isolated, and purified using ultrafiltration membrane (UF), gel filtration chromatography (GFC), and reversed-phase high-performance liquid chromatography (RP-HPLC), and the binding mechanism was explored. Twelve umami peptides were found by nano-scale liquid chromatography-tandem mass spectrometry (Nano-HPLC-MS/MS) from four phases, three of which existed throughout the processing step, and their peptide sequences were HLEEEIK (HK-7), LDDALR (LR-6), and ELY (EY-3). The umami score and the frequency of active fragments of umami were highest for LL-5, followed by EF-3. The main active sites between umami peptide and umami receptor T1R1/T1R3 were Tyr262, Glu325, and Glu292, and hydrophobic interaction and hydrogen bonding were the main forces, and bitter amino acids were also important components of umami peptides. This study provided a basis for the identification and screening of umami peptides in local chicken, also help to study the structure-activity relationship of umami peptides.