Abstract: The promotion effect of fat oxidation on myofibrillar protein oxidation was studied by establishing a protein oxidation model with different degrees of lipid oxidation, and its influence on the properties and structural characteristics of myofibrillar protein was also explored. The results showed that free radicals produced by fat oxidation could promote protein oxidation. With the increase of fat oxidation, the degree of myofibrillar protein oxidation showed a significant increase as indicated by significant changes in the contents of carbonyl, sulfhydryl and di-tyrosine (P < 0.05), whose values were 4.12, 81.33 nmol/mg, and 563.36 AU, respectively when the thiobarbituric acid reactive substances (TBARS) value was 2.5 mg/kg. As a result, the surface hydrophobicity of the protein gradually rose, whereas its rheological properties such as storage modulus and loss modulus decreased. The stable secondary structures of α-helix and β-fold were partially destroyed and transformed into unstable β-turn and random coil. Thus, the structure and functional characteristics of myofibrillar protein showed significant changes with increasing degree of oxidation.

Key words: lipid oxidation, protein oxidation, free radical, myofibrillar protein