Abstract: This study explored the impact of different oxidant concentrations and oxidation times on biochemical
characteristics and spatial structure of myofibrillar protein in back muscles of Pampus argenteus using FeCl3-VC-H2O2
hydroxyl radical-generating systems. The results showed that Pampus argenteus myofibrillar proteins were attacked by free
radicals generated from FeCl3-VC-H2O2 systems, causing changes in some amino acid side chains to produce polymers.
With the extension of oxidation time, both the high (1.0 mmol/L H2O2) and low concentration (0.1 mmol/L H2O2) oxidant
groups showed a significant increase in myofibrillar protein carbonyl content, surface hydrophobicity and dityrosine content,
and a decrease in total sulfhydryl content, but the effect of the high oxidant concentration was more significant. Raman
spectroscopic analysis indicated that, with the increase in oxidation time and oxidant concentration, the microenvironmental
polarity of myofibrillar protein was generally enhanced. The amide Ⅰ band was shifted to longer wavelength along with
a reduction in α-helix content and an increase in β-sheet content. In conclusion, P. argenteus myofibrillar protein could be
oxidized in hydroxyl radical-generating systems, leading to its structural and biochemical changes.

Key words: hydroxyl radical, protein oxidation, Raman spectroscopy, Pampus argenteus, conformation