To investigate microwave cooking, a traditional method of fish cooking known as fish boiling was assessed when the heating source of conventional external gas was replaced by a microwave. Also, a three-dimensional finite element model for simulating this cooking process was developed.
The time-dependent temperature changes of both the liquid and solid samples were predicted theoretically by coupling the analyses of electromagnetic field and heat transfer. The recommended ther- mal conductivity of a water solution with free convection (100 W m 1 K 1) for predicting temperatures of conventional exter- nal heating was found to be unsuitable for microwave heating due to the dielectric heating characteristic. This value was finally adjusted to 300 (W m 1 K 1), which made the prediction match the experi- ment very well. On this basis, the predicted spatial temperature pro- files and surface temperature distributions of the fish sample also showed good agreement with the experimental results.
We also developed a FORTRAN program that extracted all the time-dependent temperature results and the information of the node and element of the fish sample from the three-dimensional computer model. With the temperature histories and parameters that were calculated from DSC experiments, the degrees of protein denaturation of the fish sample during cooking were estimated successfully. Finally, all of the resulting files were transformed and displayed in Femap, by which the temperature and protein denaturation information could be provided directly via animation.