N-nitrosamine is a kind of carcinogenic substance, which is possibly formed in the reaction of nitrites with amino acids or secondary amines. Two in vitro model systems were designed to evaluate the influence of oxidized myofibrils protein subjected to repeated freeze-thaw cycles (0, 1, 2, 3, 4, 7, 10 times) on N-nitrosamine formation. Model system I contains diethylamine and sodium nitrite, while model system II contains only sodium nitrite as reaction solution. Oxidized myofibrils protein were added to both systems. The results revealed that as the number of freeze-thaw cycles increased, cross-linking of myosin heavy chains and the content of protein carbonyl increased, but the content of protein sulfydryl decreased, which indicates oxidization of protein occurred. The concentration of N-nitrosodiethylamine increased as the number of freeze-thaw cycles increased, especially after four cycles. Oxidized myofibrils protein promoted the formation of N-nitrosodiethylamine. The more the times of freeze-thaw cycles were subjected, the more oxidization of myofibrils protein occurred and the higher yield of the N-nitrosodiethylamine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.