Contribution of lipid and protein oxidation to rheological differences between chicken white and red muscle myofibrillar proteins

Myofibrils isolated under different antioxidative conditions from three groups of chicken muscle [breast (B_ctrl), leg (L), and breast with its iron and fat content adjusted to the level of leg muscle (B_adj)] exhibited complex viscoelastic characteristics during thermal gelation. Without antioxidants in myofibril isolation buffer, B_adj myofibrils had decreased storage moduli (G′) and loss moduli (G″) compared with Bctri myofibrils, but these values were much higher than those of L myofibrils. Lipid oxidation (TBA value) was inhibited in myofibril samples prepared using antioxidant buffers. Antioxidant treatments increased G′ and G″ of B_adj myofibrils to a level comparable to G′ and G″ of the Bctri counterparts. Different distributions of prooxidants in chicken white and red myofibrillar proteins were not an apparent major factor causing functional discrepancies between the two types of proteins. The discrepancies could be ascribed largely to fiber type-dependent myosin isoforms and polymorphism.