Influence of atmospheric-pressure cold plasma-induced oxidation on the structure and functional properties of egg white protein

This study examined the effects of atmospheric-pressure cold plasma (ACP) on the structure and functional properties of egg white protein (EWP). Egg white solution was treated with ACP for 0, 10, 20, 30, and 40 min. The structural unfolding of EWP was confirmed as the exposed free SH group content and surface hydrophobicity increased during the 30 min treatment; however, 40 min of ACP treatment showed the opposite tendency, suggesting the formation of protein aggregates. The emulsion stability of egg white emulsions was the highest at 30 min but decreased again at 40 min. In addition, the proportion of large droplets decreased as the treatment time increased up to 30 min. As a result, moderate oxidation was induced during 30 min of ACP treatment, which could contribute to the enhancement of functional properties of EWP. However, excessive oxidation caused by further ACP treatment negatively affected the enhanced functional properties. Industrial relevance: Egg whites are used as functional ingredients for a variety of food products, so the quality and functionality of egg whites can directly affect the productivity of the final products. The present study suggests the moderate oxidation of egg white protein induced by atmospheric-pressure cold plasma, which could contribute to the enhancement of functional properties. These applied studies can serve as a cornerstone for the establishment of advanced oxidation techniques that can enhance the functionality of egg whites without chemical additives, and consequently contribute to the improvement of food quality and productivity.