Effect of Prerigor Processing on the Oxidative Rancidity of Ground Light and Dark Porcine Muscles

The extent of oxidative rancidity developed during storage of ground samples of light and dark porcine semitendinosus muscles has been estimated with the thiobarbituric acid (TBA) test. The prooxidant effect of NaCl was observed in both pre‐ and postrigor ground and salted samples but the prerigor samples were much less susceptible to lipid oxidation over a 10‐day storage period. Unsalted samples ground in the prerigor state were also less susceptible to autoxidation than similarly ground postrigor muscles. When prerigor ground and salted samples were stored in bags purged with nitrogen, the rate of rancidity development was greater than when such samples were stored in atmospheric oxygen. Prerigor oxygenated light muscle samples were more susceptible to oxidation than the dark muscles and vice versa for postrigor oxygenated samples. No differences due to muscle type were observed in samples stored in nitrogen. The partial inhibition of the prooxidant effect of NaCl observed with prerigor grinding and salting is suggested to be the result of an induced high ultimate pH. The improved stability of unsalted ground prerigor muscle as compared to similarly treated postrigor muscle may also reflect a limited pH decline.