FINITE-ELEMENT MODELING OF HEAT AND MASS-TRANSFER IN FOOD MATERIALS DURING MICROWAVE-HEATING - MODEL DEVELOPMENT AND VALIDATION

A three-dimensional finite element model (FEM) was developed to predict temperature and moisture distributions in food materials during microwave heating. The FEM was tested with analytical solutions and commercial software (TWODEPEP, ANSYS) calculated values. The FEM predictions compared favorably with analytical solutions (within 0.066% of maximum temperature) and values calculated from commercial softwares (within 0.14% of maximum temperature). The three-dimensional FEM was also verified using experimental data from microwave oven heated cylinder- and slab-shaped potato specimens. A fluoroptic temperature measurement system and the near infrared (NIR) technique were used to measure temperature and moisture distributions, respectively. The FEM predicted temperature in potato samples agreed with measured results. The absolute maximum difference for slab geometry after 60 s of heating was 8.1-degrees-C (or relative difference of 15.5% from the measured value), whereas, for the cylindrical geometry, it was 8.7-degrees-C (or relative difference of 11.4%). The absolute moisture differences after 60 s of heating between FEM predictions and measured values for potato slab and cylinder were within 1.97% wet basis (or relative difference of 2.4%) and 1.85% wet basis (or relative difference of 2.1%), respectively.