Modeling the transport phenomena and structural changes during deep fat frying: Part II: model solution & validation

Abstract

A fundamental two-dimensional model to predict the heat and mass transfer that occur during the frying and cooling process of tortilla chips was solved using finite element technique. The assembly of elements method with each element being four-noded quadrilateral elements was used to obtain a two-dimensional distribution. The Gauss–Legendre method was used for the numerical integration of each of the integrals. The system of non-linear equations (including contributions from all elements) was solved using FORTRAN Power Station 4.0. A good agreement between experimental and predicted data was obtained. The parameters that were studied included water saturation, oil saturation, temperature during frying and cooling. Change in structure (shrinkage and expansion) was also verified and agreed well with the experimental data. Sensitivity analysis showed that the higher frying temperature the faster drying rate and a faster increase in the temperature and pressure of the product. More oil was absorbed at a lower frying temperature. The thicker the product the lesser the oil content. Oil absorption appeared to seize once the temperature of the product begins to increase and a crust begins to form. The cooling temperature had the most influence on oil absorption. The cooling temperature that was nearest to the temperature of the fried product led to the least amount of oil absorption.