Exploring of Multi-Functional Umami Peptides from Stropharia Rugosoannulata: Saltiness-Enhancing Effect and Mechanism, Antioxidant Activity and Potential Target Sites

Umami peptides enhance flavor and offer potential health benefits. We analyzed taste-value profiles of five novel umami peptides from Stropharia rugosoannulata using E-tongue, revealing significant saltiness variations. While PHEMQ and SEPSHF exhibited higher saltiness, their mixture with salt did not enhance saltiness compared to individual peptides. Surprisingly, SGCVNEL, initially weak in saltiness, remarkably enhanced saltiness when mixed with salt, potentially due to structural changes in low-concentration neutral salts. Additionally, except for PHEMQ, umami perception significantly improved after salt mixing. Molecular docking elucidated the salt-forming mechanism of TMC4, highlighting the P2-domain and hydrogen bonds’ role in composite structure stability. Antioxidant activity evaluation demonstrated dose-dependent effects primarily through free radical scavenging via the single electron transfer mechanism for SGCVNEL, EPLCNQ, and ESCAPQL. Docking experiments with antioxidant targets unveiled varied binding stability, indicating diverse antioxidant effects for the peptides. These findings provide valuable insights into exploring and applying versatile flavor peptides with bioactivity.