Plasma activated water (PAW) modification of PSE-like chicken protein isolate: Structural changes and enhanced film-forming properties

The oxidative effects of plasma-activated water (PAW) on the structure, oxidation, and film-forming properties of heat-induced alkaline PSE-like chicken protein isolate (PPI) were investigated. The results demonstrated that the content of active substances in PAW significantly increased with longer preparation times. PAW treatment led to the unfolding of PPI structure in the film-forming solution, evidenced by the conversion of α-helices to β-sheet and β-turn, exposure of hydrophobic groups, increased surface hydrophobicity, and a significant reduction in fluorescence intensity. Additionally, PAW facilitated the oxidation of PPI, as indicated by a decrease in total sulfhydryl content and a substantial increase in carbonyl content. Characterization of PPI films revealed that PAW treatment significantly enhanced their mechanical properties and hydrophilicity while reducing water vapor permeability. Among the treatment groups, the PAW-90 treatment group exhibited optimal tensile properties and the lowest water vapor permeability value (4.21 ± 0.36 × 10⁻⁷ (g·m⁻¹·h⁻¹·kPa⁻¹)) and oxygen permeability value (7.45 ± 0.84 × 10⁻⁸ (g·m⁻¹·h⁻¹·kPa⁻¹)). Principal component analysis further revealed the correlation between the molecular structure of PPI and its film-forming properties. In summary, PAW could induce alterations in the molecular structure of PPI, thereby improving its film-forming properties.