Oxidation and gelation of myoglobin-myosin induced by the plasma-activated water

Plasma-activated water (PAW) is a novel non-thermal processing technology in the food field. However, the interaction between PAW and protein in unwashed surimi remains unclear. In this study, myoglobin (Mb) was mixed with myosin to simulate Mb-induced degradation in unwashed surimi. The mixture was subsequently treated with PAW to investigate the impact of the reactive species within PAW on this degradation process. The results demonstrated that the Mb-myosin group exhibited slower changes in active site oxidation, protein unfolding, and molecular aggregation compared with the myosin group. The Mb-myosin group’s total sulfhydryl content dropped by 25.55%, the carbonyl content rose by 162.85%, and the particle size grew by 28.27% after PAW was processed for 80 s. Furthermore, PAW enhanced the gel-forming ability of the Mb-myosin group, increasing gel strength by 152.98% at 20 s and water-holding capacity by 16.91%. These results indicate that PAW has a relatively weaker oxidative effect on Mb-myosin compared to direct treatment of myosin by PAW. In addition, complex protein gels require a longer time to reach a moderate oxidation state. This study provides a theoretical basis for improving the gel properties of unwashed surimi with PAW technology.