T. Popova1*, P. Marinova, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria

Abstract. The changes in lipid and protein oxidative stability in response to vitamin E supplementation in the diet (400 mg/kg feed) during storage of Musculus LongissimusdorsiandMusculusSemimembranosuswerestudiedin♀Younax♂Pietrainpigs. Musclesampleswerestoredfor6daysat4°Cafterwhichthe storage continued for up to 90 days at – 20°C. Lipid oxidation was analysed by determination of 2-thiobarbituric acid reactive substances (TBARS) formed during storage of 48 h, 6 days and 90 days. The oxidation of proteins was determined by measuring the content of carbonyls formed during the same storage periods. The muscles of the pigs from the vitamin E supplemented group showed lower TBARS content for 48 h and 6 days (P<0.01). Significant influence of the vitamin E was observed after frozen storage (P<0.01) as well and lower levels of TBARS were displayed in the muscles from the supplemented group. Contrary to the lipid oxidation, vitamin E supplementation of the diet only tended to decrease the oxidation of the proteins in the muscles during the storage. However, carbonyl formation differed between the muscles. During the refrigerated storage Musculus Longissimus showed higher extent of carbonylation, whereas after frozen storage the carbonyl content was increased in Musculus Semimembranosus. In both muscles lipid and protein oxidation showed the same trends of development in the control and supplemented group, showing maximal content of TBARS and carbonyls after the 90th day of frozen storage.