Effects of hydroxyl radical oxidation on the structural and functional properties of mutton myosin

To research the impact of free radical oxidation on myosin, we established a hydroxyl radical oxidation system using iron/hydrogen peroxide/ascorbic acid. By varying hydrogen peroxide concentrations (0, 0.5, 1, 5, 10, 20 mmol·L–1), weachieved different oxidation levels ofmyosin and investigated the effects onits structural and functional characteristics. The results showed that when the H2O2concentration was 20 mmol·L–1, compared with the control group, the carbonyl content ofmyosin was 2.376 times higher, the sulfhydryl content was decreased by37.02%, the surface hydrophobicity was increased by59.13%, the solubility was decreased by19.54%, and the turbidity was significantly increased (P<0.05). Myosin emulsification, emulsification stability, and foaming capacity initially increased and then they diminished, and the maximum value was reached when the H2O2concentration was 5 mmol·L–1, whereas foaming stability remained relatively unchanged. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis research revealed increased crosslinking and protein polymerisation in oxidised myosin. The secondary structure of myosin measured by Fourier infrared spectroscopy showed that the α-helix content decreased by 14.41% and the β-fold content increased by 44.50%. These results suggested that oxidative modification alters the structural and functional properties of myosin, providing valuable insights for its structural and functional analyses.