Effects of oxygen concentration in modified atmosphere packaging on water holding capacity of pork steaks.

The pork steaks were stored at 4 °C for 7 days to investigate the effect of oxygen concentrations (0%, 20%, 50% and 80%) in modified atmosphere packaging and air packaging on water holding capacity (WHC) of raw meat and cooked meat. The ultrastructure of muscle, and oxidation of lipids and proteins were also studied. The results showed that purge loss of meat increased with increasing oxygen concentration (P < .05). The extent of oxidation of lipids and proteins was greater in meat packaged under 50% and 80% oxygen. It suggested that the decreased WHC of meat was closely associated with oxidation degree during postmortem storage. Notable sarcomere shortening was consistent with the decreased WHC of meat packaged with 50% and 80% oxygen. It is plausible that the higher drip loss of meat in air packaging was induced by other factors other than the oxidation of protein.