Consumer acceptability and physiochemical characteristics of modified atmosphere packed beef steaks

The objective of this study was to investigate the physiochemical changes of beef steaks packed under various combinations of gasses and the relationship between consumer perception of flavour and acceptability of modified atmosphere packed beef steaks during retail display. Experimental gas atmospheres included: 40%, 50%, 60%, 70%, and 80% oxygen, with all packs containing 20% CO(2) and the make up gas N(2). Steaks were stored at 4°C for 12 days and tested for lipid and protein oxidation, heme iron, colour, oxymyoglobin concentration, Warner-Bratzler shear force (WBSF) and consumer acceptability for the resulting cooked meat. The results from 134 consumers indicated a directional preference for the steaks stored in packs containing 40% and 80% oxygen. Samples with high oxygen levels, particularly the O(2)60 and O(2)70 treatments, were positively and significantly (P<0.01) correlated to sensory toughness, and significantly (P<0.05) negatively correlated to juiciness, as determined by consumers. However, the O(2)40 samples were most negatively (P<0.001) correlated to toughness and positively (P<0.01) correlated to juiciness, which shows that, in general, these higher O(2) levels, >40%, imparted greater meat toughness as determined by the consumers. The greater directional acceptance of the O(2)40 samples may be linked to the consumer perceived reduction in sensory toughness and increases in juiciness.