This article presents the application of an improved differential distillation model for the study of the formation of trans linoleic acid and trans linolenic acid during batch deodorization of canola oil, combining computational simulation and response surface methodology. The effects of four factors (temperature, duration of the batch and the initial contents of cis linoleic acid and cis linolenic acid) in the final content of trans polyunsaturated fatty acids of the deodorized oil were investigated. Following previous works, group contribution equations were used in the prediction of the required physical properties. To exemplify the usefulness of our modeling and evaluate its performance, the simulation results were compared with experimental values reported in the literature. The inclusion of kinetic models in the simulation program and the careful modeling of the reaction features allowed a good agreement between the results of the experimental work and the values estimated by our RSM equations. (c) 2006 Elsevier B.V. All rights reserved.