Performance comparison between batch and continuous thawing of food products assisted by radio frequency heating

Radio frequency (RF) assisted heating of foods is an established technique used in food processing such as postharvest treatment of in-shell fruits, drying of food materials and products. More recently, it has been proposed as industrial solution for continuous tempering of frozen meat blocks. In the last years, scientific literature has shown interest on using RF heating to enhance food thawing prior to further processing or consumption, due to the possibility to reduce processing time, raise the power efficiency of the thawing process, and eventually provide better quality and safety of the thawed product. The purpose of this study was to evaluate the performance between batch and continuous thawing of food products assisted by RF heating. A pilot scale RF system with 27.12 MHz and 6 kW used to thaw 1.2 kg block of minced lean beef meat and to evaluate the performance under different conditions. The results showed that continuous RF thawing slightly improved the heating uniformity and relatively uniform heating rate compared to batch system under the same process conditions. End point temperatures of-0.2°C ±1.5 and -0.4°C ± 0.7 were achieved at the center of the sample in 17 min thawing time using batch and continuous conditions, respectively. These comparison results may provide detailed performance information to optimize and design processing parameters and, to promote further practical applications of RF heating in food processing industry.