Preparation of steam explosion modified pea protein peptides and its antibacterial mechanism against Staphylococcus aureus

Abstract

In this study, the enzymatic hydrolysis process of steam explosion modified pea proteins was optimized through single-factor experiments and a Box-Behnken experimental design. The maximum degree of hydrolysis of 23.13% was achieved at 7.38% substrate concentration (w/v), 5% enzyme-to-substrate ratio (w/w), pH 9.5, and 55 °C for 3 h. Steam explosion modified pea protein peptides (SE-PPP) exhibited strong antibacterial activity against Staphylococcus aureus (S. aureus), with a minimum inhibitory concentration of 0.0244 mg/mL. Mechanistic studies revealed that SE-PPP disrupted the integrity of bacterial cell wall and membrane, as evidenced by increased alkaline phosphatase activity, decreased adenosine triphosphate levels, reactive oxygen species and malondialdehyde accumulation. These effects led to nucleic acid and protein leakage, thereby inhibiting bacterial proliferation. These findings confirmed that steam explosion pretreatment markedly enhanced the yield of low-molecular-weight peptides from pea protein. Moreover, the obtained SE-PPP had excellent antibacterial activity against S. aureus, supporting its potential as a natural food preservative for the high-value utilization of pea proteins.