Cold plasma-assisted enzymatic hydrolysis of shrimp protein for bioactive peptide production: Structural, antioxidant, and molecular docking characterization

This study systematically examined the effects of cold plasma (CP) pretreatment on the enzymatic hydrolysis, structural properties, and antioxidant activity of shrimp protein hydrolysates (SPH). After CP pretreatment for 6 min, the degree of hydrolysis increased from 24.67% to 28.84%, accompanied by a significant rise in the proportion of low-molecular-weight peptides. Structural analyses revealed that CP induced protein unfolding and increased active site accessibility, as evidenced by elevated random coil content and enhanced surface hydrophobicity. CP pretreatment followed by enzymatic hydrolysis significantly improved the antioxidant capacity of SPH compared to hydrolysis alone, increasing the DPPH and ABTS radical scavenging rates of SPH to 39.87% and 54.57%, respectively. Four peptides (LIDDHFL, AQVGPIGPR, SEGPLKGVL, AEMNPEKF) were identified and screened using mass spectrometry and virtual screening techniques, with their antioxidant activities validated via in vitro assays. Molecular docking revealed strong binding affinity between these peptides and Keap1, suggesting the peptides may interfere with Keap1-Nrf2 interactions through competitive binding to Keap1 to exert antioxidant activity. These findings established CP pretreatment as an effective and promising strategy for producing bioactive antioxidant peptides.