Oxidative and lipolytic deterioration of different muscles from free-range reared Iberian pigs under refrigerated storage.

Three different type of muscles, two glicolytic (Serratus ventralis and Longissimus dorsi) and one oxidative (Masseter) were displayed under refrigeration at +4 °C during 10 days to evaluate differences in lipolytic and oxidative changes of different muscles with different metabolic pattern. Thiobarbituric acid reactive substances (TBARS), phospholipid content, hexanal content and fatty acid profiles of neutral and polar lipid fractions were analysed at day 0 and day 10. Phospholipid content (g phospholipids/g intramuscular fat) significantly (P<0.035) decreased from day 0 to day 10 in m. Masseter (0.33 vs. 0.25, respectively), but not in m. L. dorsi (0.12 vs. 0.09, respectively) and m. S. ventralis (0.19 vs. 0.14, respectively). Changes in fatty acid profiles of neutral and polar lipids significantly differed among muscles after storage. Slight differences were found in neutral lipids from m. L. dorsi and m. S. ventralis, while neutral lipids from m. Masseter were highly altered. Great changes affected fatty acid profiles from polar lipids in the three muscles. m. Masseter muscle showed significantly higher (P<0.000) TBARS values (1.13, 0.65 and 0.60 mg MDA/kg meat, respectively) and hexanal content (689.2, 241.2 and 355.8 μg/g meat, respectively) than m. L. dorsi and m. S. ventralis. In conclusion, oxidative meat is more prone to oxidative and lipolytic deterioration than glycolytic muscles during refrigerated storage and as a consequence of that a lower shelf-life.