Species-specific Myoglobin Oxidation

4-Hydroxy-2-nonenal (HNE) is a reactive secondary lipid oxidation product present in meat products. Oxymyoglobin (OxyMb) oxidation is accelerated by HNE adduction. The adduction of HNE to the histidine (His) residues of OxyMb is believed to alter the tertiary structure of OxyMb and make the heme group more vulnerable to oxidation. Previous studies suggested that the HNE effect on OxyMb oxidation was species-specific. This thesis investigated the effect of HNE on the redox stability of OxyMbs derived from seven meat-producing animal species. The results suggested that the effect of HNE on OxyMb oxidation was correlated with the number of His residues with a greater HNE effect on OxyMbs that contained more His residues (P\u3c0.05). Moreover, ovine myoglobin (Mb) redox stability was investigated in HNE- and microsome containing models. HNE enhanced ovine OxyMb oxidation at all pH/temperature conditions studied and adduction of HNE to Mb was identified at amino acid residue His 120, His 25 and His 65. The ovine microsome model study found that elevated α-tocopherol concentration enhanced lipid and Mb redox stability relative to controls (p\u3c0.05). HNE-treated ovine Mb caused greater lipid oxidation compared to control ovine Mb in control microsomes (P\u3c0.05)