Hydroxyl Radical-Driven Structural De-antigenicity of Casein: A Comparative ROS Mechanism in Argon Plasma

Casein (CN) is a major allergen in bovine milk, and reactive species generated by cold plasma have been shown to modulate its conformation and antigenicity. The effects of scavenging major reactive oxygen species (ROS) from cold argon plasma on CN modification and antigenicity were investigated in this study. Notably, scavenging hydroxyl radicals (·OH) partially reversed the plasma-induced reduction in IgE-binding capacity, with the value recovering from 24.37% to 80.44%. Structural analyses indicated that ·OH predominantly drives CN degradation and insoluble aggregation. Moreover, ·OH and singlet oxygen ( 1 O 2 ) induced irreversible oxidation and conformational rearrangement, while hydrogen peroxide (H 2 O 2 ) caused mild, partially reversible oxidation. This study highlights irreversible oxidative damage by ROS and offers insights into antigenicity regulation during cold plasma treatment.