Oxidative stability of chilled pork chops following long term freeze storage

Colour stability and development of lipid oxidation were followed during chill storage for 6 days of chops from M. Longissimus dorsi produced from pigs with high (6.3) and low (5.5) ultimate pH (pH(u)). The chops from the same individual pigs were either chill stored at 2 days post-mortem or after frozen storage for 30 months (pre-frozen). Initial redness, measured as tristimulus parameter a(*), was lower for pre-frozen chops than for fresh chops. Chops with the high pH(u) had a stable a(*)-value during chill storage, while chops with the low pH(u) showed a rapidly decreasing a(*)-value both for fresh and pre-frozen chops. In contrast, initial lipid oxidation, measured as TBARS, was similar for pre-frozen and fresh chops prior to chill storage for both the high and the low pH(u) meat but developed most significantly in pre-frozen, low pH(u) meat. Individual differences in colour stability and development of lipid oxidation between pigs were notable for pre-frozen low pH(u) meat and need to be considered in quality control since meat from single pigs otherwise might give problems.