Sustainable utilization of rice wine cake: The integration of in vitro and in silico method for exploring antioxidant peptides.

Rice wine cake was sustainable utilized for bioactive peptide development. Alkaline protease was verified optimal among selected industrial proteases based on the highest DH (15%), 77.4% content of peptide <1 kDa, and potent antioxidant activity of its hydrolysate (APH). APH reduced intracellular ROS by approximately 50% in the oxidant injury HaCaT cells. There were 703 peptides identified from APH by Nano-LC-Q-Orbitrap MS, and 57.0% of oligopeptides exhibited terminal amphiphilicity. The Keap1-binding potential were predicted. Among the ones with binding energy < -7.0 kcal/mol, GLPPEWY, QHSIVATPF, and WIDFPRAPQ with amphiphilic termini were chosen, and ATPFWQPATF and AAAPWPW with non-amphiphilic termini, for ROS scavenging. At 50 μM, QHSIVATPF and ATPFWQPATF respectively acted the highest (69.8%) and lowest ROS inhibition (40.1%). The molecular dynamics simulations well illustrated the mechanistic differences between the two. The three amphiphilic peptides were confirmed to promote nuclear Nrf2 accumulation. The findings suggested the significance of terminal amphiphilicity for antioxidant peptides.