Modeling of microwave thawing and reheating of multiphase foods: A case study for packed rice

Abstract

Microwave (MW) thawing and reheating of porous foods such as rice is a common practice, but uniform heating can be difficult to achieve. Computer simulation models were developed using the finite-element method to study MW thawing and reheating of packed rice. A method to obtain an apparent thermal conductivity was proposed, which accounts for heat distribution by water evaporation and condensation through the air pores in the sample. Reheating experiments of mashed compact rice and regular porous rice were carried out on a flatbed MW oven for 90 s. Similarly, thawing experiments were conducted on porous rice for 180 s. Good agreement between simulated and experimental results was obtained when correcting for thermal conductivity of the pores and for the volumetric power absorption between the frozen and thawed fractions This can help in the design of specifically designed porous foods and containers that allow for fast and homogeneous reheating.