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

Abstract Objectives Lees are the major by-product of Huangjiu brewing and are prone to decomposition due to abundant protein residues. This study aims to convert the lees into high-value peptides with umami and antioxidant difunctionals. Materials and Methods Herein, a one-step hydrolysis method combined with flavorzyme followed by amylase pretreatment was developed and optimized. The target peptide fraction was collected and evaluated after ultrafiltration and ethanol precipitation, and then identified by nano-high-performance liquid chromatography–tandem mass spectrometry. The target peptides were filtered through virtual screening, sensory, and radical scavenging verification. Results The results show that 80 U/g amylase and 3500 U/g flavorzyme synergistic hydrolysis at 50 °C for 3 h performed best for umami intensity and antioxidant activity. A total of 5266 peptides was identified from the 80% ethanol precipitation fraction, finally secreened 7 umami peptides. The umami recognition threshold of the 7 peptides ranged from 0.38 to 0.66 mmol/L in water. Among them, DPDGW and DNPNW exhibited good DPPH antioxidant ability with IC50 values of 0.6982 mg/mL 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. Conclusion This study shows that Huangjiu lees is a potential resource for flavor and bioactive peptide development, which provides a reference for other waste protein recycling.