A Comparison of Conventional and Radio Frequency Thawing of Beef Meats: Effects on Product Temperature Distribution

This study examined the use of pilot-scale radio frequency (RF) heating for thawing beef meat blends (lean, 50:50 lean/fat and fat). The aim was to thaw blocks (4 kg) to within a target temperature range of −1 to +5°C. Post-thawing temperature distribution in the blocks was compared to that of blocks thawed by conventional air thawing. The optimum RF conditions for thawing lean meat was 35 min of RF heating delivered in a noncontinuous fashion (20 min on, 10 min off, and followed by 15 min on) at 400 W, which gave a mean temperature of 0.2°C (SD 1.8). By comparison, conventional thawing was achieved in 50 h 20 min which represented an 85-fold difference in thawing time. Comparable uniformity of temperature distribution was obtained by each method. For the lean/fat mixture and 100% fat, the target range could not be achieved due to problems of runaway heating. The latter phenomenon relates to the manner in which the absorbed energy is transferred throughout the material as influenced by the thermophysical properties of the product.