Abstract: The present study investigated the effects of different oxidation degrees (0, 1, 5, 10 and 20 mmol/L H2O2) induced by a Fenton oxidation system on the functional properties of myofibrillar proteins (MP) from Esox lucius muscle. Increasing oxidation degree caused an increase in carbonyl group content and turbidity and a significant decrease in protein solubility (P < 0.05). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed a greater degree of cross-linking and protein aggregation in oxidized MP. Fourier transform infrared spectroscopic (FTIR) analysis suggested that oxidation caused conformational changes in MP. The results of functional characterization indicated that moderate oxidation (1 and 5 mmol/L H2O2) substantially increased the foaming capacity of MP by 280% (P < 0.05) while having little effect on the emulsifying stability (which remained at above 90%). However, oxidation decreased the emulsifying properties of MP; the influence of moderate oxidation (1 and 5 mmol/L H2O2) was small, while excessive oxidation (> 10 mmol/L H2O2) led to a significant decrease in emulsifying capacity and emulsion stability. These results indicated that mild oxidation could improve the foaming capacity, and provide better functional properties of MP.

Key words: Esox lucius; myofibrillar proteins; protein oxidation; structural properties; functional properties