Enhanced antibacterial performance of chili pepper seed protein hydrolysates by high hydrostatic pressure assisted enzymatic hydrolysis on Staphylococcus aureus: structural basis and mechanistic insights.

Antibiotic resistance of Staphylococcus aureus threatens public health. Plant by-product protein hydrolysates contain antibacterial peptides as antibiotic alternatives, but compact native protein structures restrict hydrolysis efficiency and antibacterial fragment release. This study applied high hydrostatic pressure (HHP) to assist papain hydrolysis of chili pepper seed protein (PSP) to improve hydrolysis efficiency and antibacterial activity. Pressurisation (100-500 MPa) enhanced PSP hydrolysis degree by 4.48-28.84%. Hydrolysis at 100 MPa gave rise to hydrolysate optimal antibacterial activity with 18.90% and 10.25% higher inhibition rates and zones. Structural and physicochemical analysis indicated that hydrolysis at 100 MPa increased the α-helix content by 23.15%, surface hydrophobicity by 20.50%, < 3 kDa peptides by 284.07%, and improved solubility and dispersion. These variations strengthen hydrolysate capacity on membrane binding and disruption, and form a favorable antibacterial microenvironment. These results provide an effective strategy to optimize enzymatic hydrolysis and high-value utilization of chili pepper seeds.