The inactivation of pectinesterase (PE) activity in gazpacho (a Spanish ready-to-use cold vegetable soup) under pulsed electric fields (PEFs) was studied. Samples were exposed to 4 mu s monopolar or bipolar square-wave pulses at 5-35 kV cm(-1) electric field intensity for up to 1500 mu s and 200 Hz (temperature below 40 degrees C). Inactivation of PE was greater when treatment time and electric field intensity increased. and bipolar pulses were more effective inactivating PE than monopolar ones. Estimation of parameters and quantities involved in the tested models were performed within the Bayesian framework. The kinetic evolution of the enzyme was explained using a 3-parameter biexponential model based on a mechanism involving two irreversible consecutive steps. Rate constant k(1) was not dependent on neither electric field intensity nor pulse polarity. Rate constant k(2) and ratio between the activities of intermediate forms and the native ones of the enzyme A were affected by those conditions. (C) 2009 Elsevier Ltd. All rights reserved.