Lipolytic and oxidative changes during refrigeration of cooked loin chops from three lines of free-range-reared Iberian pigs slaughtered at 90 kg live weight and industrial genotype pigs

Lipolytic and oxidative changes in cooked and refrigerated loin chops from Iberian and industrial genotype pigs were studied. Iberian pigs were free-range-reared and fed with access to pasture and a concentrate feed based on cereals. M. longissimus dorsi from industrial genotype pigs (Large White-Landrace × Large White) were obtained from a local slaughterhouse. Cooked loins from Iberian pigs showed higher intramuscular fat (IMF) (p<0.05) and lower polar lipid (PL) contents than the industrial genotype pig loins (g PL/g fat, p<0.05). The increase of TBA numbers (mg MDA/kg defatted dry basis) after cooking and refrigerated storage was significantly higher (p<0.05) in the industrial genotype pig loins than in the Iberian ones. After cooking and refrigerated storage, percentages of polyunsaturated fatty acids (PUFA) from intramuscular fat and the polar lipid fraction decreased while saturated and monounsaturated fatty acid percentages increased. Linoleic, arachidonic and total PUFA proportions in the polar lipid fraction, decreased in the four groups but these were only statistically significant in the cooked loins from the industrial genotype pig breed.