Reduction of pectinesterase activity in a commercial enzyme preparation by pulsed electric fields:: comparison of inactivation kinetic models

The inactivation of pectinesterase (PE) in a commercial enzyme preparation (CEP) under high intensity pulsed electric fields (HIPEF) was studied. After desalting and water dilution of the raw CEP, samples were exposed to exponentially decay waveform pulses for up to 463 mu s at electric field intensities ranging from 19 to 38kVcm(-1). Pulses were applied in monopolar mode. Experimental data were fitted to a first-order kinetic model as well as to models based on Fermi, Hfilsheger or Weibull. equations to describe PE inactivation kinetics. Characteristic parameters for each model were calculated. Relationships between some of the parameters and process variables were obtained. The Weibull model yielded the best accuracy factor. The relationship between residual PE and input of electrical energy density was found to be that of exponential decay. (c) 2005 Society of Chemical Industry.