Effect of magnetic field modification on oxidative stability of myoglobin in sarcoplasm systems

•Oxidative stability of myoglobin (Mb) was investigated under magnetic field treatment.•The central iron was protected for porphyrin ring first oxidized by hydroxyl radical.•12 mT magnetic field could slow down oxidation damage of hydroxyl radical to Mb.•Sarcoplasmic protein shielded Mb from oxidation damage caused by magnetic fields. This study aimed to investigate the effect of magnetic fields (0, 3, 6, 12 mT) on the oxidation characteristics of myoglobin (Mb) in the sarcoplasmic protein (SP) system and to understander the underlying mechanism. The metmyoglobin content, Soret band of heme iron porphyrin, protein conformation and molecular weight distribution were measured in different Mb and SP samples. The results showed that the primary oxidation site of hydroxyl radical on Mb was likely to be the porphyrin ring structure and the side chain group of protein rather than the central iron atoms, what’s more, 12 mT magnetic field treatment had an inhibitory effect on the oxidative damage induced by hydroxyl radical.