Modeling heat and mass transport during microwave heating of frozen food rotating on a turntable

Abstract

Microwave heating of frozen foods involves multiple physics and food product development has been trial-and-error in the food industry. Multiphysics models can be used to understand microwave interactions and can assist in design of food that can be heated more uniformly. A comprehensive three-dimensional finite element model for describing microwave heating of a food product on a rotating turntable is developed including multiphysics of Maxwell's electromagnetic heating, energy conservation, Darcy's velocity, mass conservations of water and gas, and phase change of melting and evaporation of water. The necessity of incorporating mass transfer physics was investigated and confirmed. Twelve discrete rotational steps were used in one rotational cycle. Two approaches of updating dielectric properties at each rotational step (typical) and each cycle (simplified) were evaluated. The models using typical and simplified approaches were developed and validated for heating of a 550 g tray of frozen mashed potato for 6 minutes in a 1250 W microwave oven on a rotating turntable. The spatial variation of the top surface temperatures of the mashed potato acquired by an infrared camera, the transient temperatures at six locations recorded by fiber optic sensors, and the total moisture loss during heating all showed good agreement with the simulation results for both approaches. The typical and simplified approaches had similar RMSE values of transient temperatures of, respectively, 13.1 and 13.2 °C, while the RMSE values between experimental replications was 8.0 °C. The RMSE values of total moisture loss of were similar (2.2 and 2.4 g) for both approaches. With 83% reduction in computation time for the simplified approach, this method can be used to evaluate the microwave heating of food products and accelerate microwaveable food products development.

Emerging food processing technologies and factors impacting their industrial adoption

“…The food industry has adopted the technique because of its rapid and uniform energy transfer, selective and volumetric heating, easily controllable and clean environment at the point of use (Maloney and Harrison 2016, Tang 2015, Leonelli and Mason 2010, Chen et al 2016. The food industry is developing more and more products especially well-suited to microwave heating.…”

“…This technology has an advantage over conventional microwave heating because it utilizes longer wavelengths than microwave which can penetrate deeper into the food product without surface overheating or hot or colds spots (Shaheen et al 2012). Though, the whole process needs an optimization prior to its application especially in the case of a composite food material, or a biphasic food system (Chen et al 2016).…”

Physicochemical properties of rice analogs based on multi-level: influence of the interaction of extrusion parameters

“…This was because that the inhomogeneity of microwave heating affected the migration of moisture. [32,33] There were also differences in the distribution and variation of electric field in microwave oven when the heating frequency of microwave was different. [34,35] Hot air drying was mainly based on air heat conduction so that the moisture in RA moved to the outside and finally evaporated to achieve the purpose of drying.…”

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

“…Liquids heating with microwaves have uneven heating distribution in the water flowing due to non-uniform electric field patterns. Uniformity in liquid layer heating can be solved by utilizing a focused system and taking in account factors which influence the heating patterns like dielectric properties, ionic concentration, volume, and product shape [37,44].…”