MINIMISING PROTEIN OXIDATION IN RETAIL-PACKED MINCED BEEF USING THREE-GAS MA-PACKAGING

Minced beef is usually packed in high oxygen modified atmosphere packaging (MAP) with a gas mixture consisting of 70-80% oxygen (O2) and 20-30% carbon dioxide (CO2). Unfortunately, this results in rubbery and less juicy beef patties with a more rancid flavour compared with fresh or nonoxygen packed beef. To establish whether three-gas MAP (O2, CO2 and N2), instead of two-gas MAP (O2 and CO2), would affect sensory attributes, shelf life, protein and lipid oxidation, minced beef was packed in MAP with either 40%, 50% or 80% O2 and 20% or 40% CO2 with N2 as filler gas. When comparing traditional MA-packaging (80% O2 + 20% CO2) with a low oxygen packaging atmosphere (40% O2 + 20% CO2 + 40% N2), the latter is seen to increase the meat oxidative stability during storage but decrease acceptability and shelf life. In contrast, high oxygen MAP (80% and 50% O2) results in more oxidation but a longer shelf life. However, this was not sensorially detectable in the first five days of storage. To maintain shelf life, packaging in 50% O2 + 40% CO2 + 10% N2 or 80% O2 + 20% CO2 is preferable, although this gas mixture will not prevent lipid or protein oxidation in the meat.