Radio-frequency thawing of food products – A computational study

• Food thawing assisted by RF was modeled and the model was experimentally validated.
• Food thawing assisted by RF heating is surely faster than conventional thawing.
• Hot spots can be a major disadvantage of a RF thawing system.
• Optimization methods can help designing better RF system for thawing purposes.

Main goal of optimal thawing is to minimize thawing time with least damage to the quality of frozen food products. Microwave (MW) and radio frequency (RF) applications have potential for their use in industrial thawing. Higher penetration depths of RF contribute to a better distribution of energy generated by the interaction between food and electromagnetic field, and thus help to improve the heating uniformity and to minimize runaway heating. Modeling is one way to design and to optimize such process where complexities due to coupling the heat transfer with phase change and the solution of electric field are faced. Therefore, the objectives of this study were to develop a computational model to determine temperature distribution in frozen lean beef during thawing and experimentally validate the model. For this purpose, a commercial software, based on finite element method, was used to solve coupled heat conduction and electric field in a 3D domain with temperature dependent thermo-physical and dielectric properties. Experimental data used to validate the model referred to a 50 Ω and a free-running oscillator RF systems with various sized samples. Comparison of simulation results agreed well with experimental data, and the mathematical model was reported to be used for designing RF systems to mitigate the effect of overheating at the surfaces of the sample.