Oxidation in HiOx-packaged pork Longissimus muscle predisposes myofibrillar and sarcoplasmic proteins to N-nitrosamine formation in nitrite-curing solution.

The effect of meat protein in situ oxidation on the formation of N-nitrosodiethylamine (NDEA) was investigated. Fresh minced pork was untreated (Con) or treated with 700mg/kg α-tocopherol (Toc) or 300mg/kg tea polyphenols (PPE), packaged in a HiOx atmosphere (78.8% O2, 18.8% CO2, 2.4% N2), then stored at 2±1°C for up to 10days. Crude myofibrillar (MP) or sarcoplasmic (SP) protein (20mg/mL) extracted from stored meat was reacted with 43μM sodium nitrite at 80°C for 1h. Lipid oxidation was totally inhibited in PPE pork but increased in Con and Toc samples after 10days. There was significant protein oxidation (losses of sulfhydryls, formation of protein carbonyls) in both MP and SP in all samples during storage. However, the Con group suffered more extensive protein oxidation than Toc and PPE and produced more NDEA (P<0.05), indicating that protein oxidation promoted nitrosation.