Comparison of the Quality of Cooked Beef Products Cooled by Vacuum Cooling and by Conventional Cooling

The influence of vacuum cooling on the quality of large cooked beef joints injected with brine was studied as compared with conventional cooling methods including air-blast, slow-air and waterimmersion cooling. Samples were cooked in an oven at 80 °C until core temperatures reached 70 °C and then cooled to core temperatures of 4 °C. Mean results showed that vacuum cooling was very rapid (2.8 h) compared to water-immersion (14.2 h), slow-air (10.3 h) and air-blast (8 h). The chill loss was higher for vacuum cooled joints while total yield was reduced to less than 100%. However, sensory analysis showed that water-immersion cooled samples were more tender, juicy and had better binding cohesion than the other samples. Vacuum cooled samples showed better overall colour acceptability while slow-air samples had the lowest overall acceptability. Instrumental texture results indicated a similar trend to sensory analysis with the highest WarnerBratzler shear force required for the vacuum cooled joints. Concentration of malonaldehyde in samples measured by the Thiobarbituric acid method was used as an indicator of lipid oxidation with vacuum cooled samples having highest values after 35 d storage. Average total viable counts after cooling were lower in vacuum cooled samples than the other samples.