Abstract

By applying the transition state theory, enthalpy-entropy compensation was studied for browning kinetic data obtained during deep-fat frying of both impregnated and control potato strips (Solanum tuberosum L., Desiree variety). The main objective was to study an eventual change in the browning mechanism during frying, and the effect on it of solutes impregnation (corn syrup DE 42 and NaCl). Two alternative approaches were used in order to obtain the isokinetic temperature: enthalpy/entropy relationship and frequency factor/activation energy relationship. Values of 333.1 and 335.9 K were found respectively. Both values are significantly lower than the harmonic mean temperature which was found to be 397.0 K, meaning that the mechanism of reaction is entropy controlled. A statistical analysis carried out for the data of enthalpy of activation against the entropy of activation showed that only one mechanism is present for browning during frying and that the impregnation of the strips with the studied solutes had no effect on the reaction mechanism. © 2003 Elsevier Ltd. All rights reserved.