Effects of Mild Oxidative and Structural Modifications Induced by Argon Plasma on Physicochemical Properties of Actomyosin from King Prawn (Litopenaeus vannamei)

In the present work, the structure and physicochemical properties of natural actomyosin (NAM) extracted from king prawn (Litopenaeus vannamei) and subjected to atmospheric pressure plasma jet (APPJ) generated in argon gas as a function of the treatment time were examined. The results revealed that prawn NAM exhibited a correlating decrease in pH from 7.06 ± 0.03 to 6.92 ± 0.02 and a slight increase (p > 0.05) in solubility from 91.89 ± 1.57 to 96.86 ± 1.19 within the first few minutes of plasma exposure as a result of the formation of soluble aggregates. A rise in turbidity was also noted, confirming the occurrence of protein aggregation. These changes were also accompanied by a rise in emulsifying activity from 48.96 ± 1.66 to 67.31 ± 1.39 m2/g (p < 0.05) and a nearly 50% increase in foaming capacity after 5 min of APPJ exposure. The modulation of these properties occurred as a result of conformational changes in NAM evident by various complementary structural analyses conducted. Overall, these findings show that mild oxidation from argon plasma can be used for modification of protein functionality and emphasize the need for optimal selection of plasma processing conditions.