Identification and characterization of novel dual-function antioxidant and umami peptides from protein hydrolysates of Huangjiu lees

Lees were the major by-product of Huangjiu brewing, and prone to decompose due to abundant protein residues. To convert the lees into high-value peptides with umami and antioxidant difunctional, herein, a one-step hydrolysis method combined with flavourzyme followed by amylase pretreatment was developed and optimized. The target peptide fraction was collected and evaluated after ultrafiltration and ethanol precipitation, then identified by nano-HPLC-MS/MS. The results show that 80U/g amylase and 3500U/g flavourzyme synergistic hydrolysis 50℃ for 3h performed best umami intensity and antioxidant activity. A total of 5266 peptides was identified from the 80% ethanol precipitation fraction, then filtered 7 umami peptides through virtual screening, sensory, and radical scavenging verification. The umami recognition threshold of 7 peptides ranged from 0.38 to 0.66 mmol/L at water. Among them, DPDGW and DNPNW exhibited well DPPH antioxidant ability with IC50 values of 0.6982 and 0.4315 mg/mL, respectively. Additionally, molecular docking studies indicated that all umami peptides tend to interact with the T1R3 receptor through hydrogen bonds and van der Waals forces, involving key residues such as ASN68, SER104, HIS145, SER276, VAL277, GLU301, ALA302, THR305, and HIS387. This research provides a reference for the flavor peptide resource development, oriented towards dual functionality in flavor and health.