Comparison of Oxidative Processes on Myofibrillar Proteins from Beef during Maturation and by Different Model Oxidation Systems

The aim of this work was to compare the oxidative processes occurring in myofibrillar proteins during meat maturation and after an in vitro exposure to different enzymic and nonenzymic oxidative systems. Myofibrils were prepared from bovine Longissimus lumborum and Diaphragma pedialis at day 1 and day 10 post-mortem. Myofibrillar protein oxidation was measured by the carbonyl content, with the 2,4-dinitrophenylhydrazine (DNPH) method, and by (thiol group) SH content with the 2,2‘-dithiobis(5-nitropyridine) (DTNP) method. Polymerization and/or fragmentation of oxidized proteins were estimated by SDS-PAGE and Western blot analysis using a polyclonal antibody to myosin. Oxidation of myofibrillar proteins is dependent upon the different metal-catalyzed oxidation (MCO) systems. The increase in carbonyl content and also the decrease in SH content of myofibrillar proteins, after maturation of 10 days, were similar to those obtained after a 1 h incubation of myofibrillar proteins in the presence of several MCO sy...