Estimation of dielectric properties of osmodehydrated foods by inverse numerical technique

J.R. ARBALLO; L.A. CAMPAÑONE; J.A. BAVA; R.H. MASCHERONI

Atenas

Conferencia; 29th EFFoST International; 2015

EFFOST

The present work deals with the estimation of dielectric properties of food materials during heating process. A microwave heating system was employed to heat the samples, previously treated by osmotic dehydration. It includes a microwave power generator, from which the signal is split into two equal and coherent wave fronts through a power splitter in waveguide and both signals are conducted through the elbows to a straight waveguide section where the testing sample can be introduced. During the experiments central and surface temperatures were registered by optical sensors. Besides, a 3D mathematical model was developed, by solving the energy transfer during the microwave heating process, considering dielectric properties of the product to be temperature dependent. The model solved the electromagnetic energy distribution outside and its value inside the foods through the solution of Maxwell equations. The mathematical model was employed to simulate temperature data obtained from using the prototype equipment developed. The numerical predictions were compared with experimental values. For each thermal history, the standard deviations were obtained and the property values that minimized an error function were considered as valid (inverse technique). These results were validated with experimental data obtained for osmodehydrated pears in our laboratory and were contrasted with correlations presented in literature.