Effect of Atmospheric Cold Plasma (ACP) Treatment on Zein-Thymol Composite Particles: Enhanced Encapsulation Efficiency

Abstract

Abstract The atmospheric cold plasma (ACP) treatment was applied in this study to assist the preparation of zein-thymol (ZT) composite particles and the effects under different ACP treatment power were studied. The results showed the encapsulation efficiency (EE) of ZT composite particles was significantly increased from 39.61 ± 2.78% (untreated) to the maximum of 80.35 ± 5.91% (ACP-50 W). The plasma-treated ZT composite particles exhibited higher Z-potential, conductivity, and surface hydrophobicity, especially for samples treated under 50 ~ 60 W. Micro-structural analysis showed that plasma induced disruption of α-helix packing order and increased content of β-sheet and β-turn, accompanied by more formation of disulfide bonds. Results suggested that the reinforcement of hydrogen bonding force, hydrophobic interaction and electrostatic interaction between zein and thymol were accounting for the increased EE of ZT particles treated via ACP. This study opens up new opportunities that ACP could be developed as an effective assisting approach in preparation of zein-based nutrient substance delivery systems.