This work discusses efficiency of pulsed electric field (PEF) treatment of cellular material with time-variable electric field strength, E. The potato was selected as a model tissue. Computer model, based on electroporation theory, was developed to simulate different strategies of E value changes. In the experimental part of this work, the PEF treatment was applied to disk-shaped and sliced samples using a laboratory compression chamber, equipped with a PEF-treatment system. The experiments were done using PEF generator that provided pulses of near-rectangular shape, the pulse duration was t(i) = 1000 mu s the value of E was varied within 200 and 800 V/cm, and the total time of PEF treatment, t(PEF), was varied within 0 and 0.1 s. The electrical conductivity disintegration index, Z, was used for characterization of the PEF-induced damage of potato tissue. Both theory and experiment predicted the minimum power consumption W-o at the optimal value of E-o approximate to 400 V/cm. The computer simulation predicted that application of protocols with time-variable electric fields would allow optimization of PEF treatment with initial electric field E-i deviating from the optimal value E-o. PEF experiments revealed that exponential increase of E values can be useful at small initial electric field strengths, E < E-o, as far as it allows significant improvement of PEF-treatment efficiency. The PEF experiments with pressing of potato slices have shown that PEF treatment before pressing was more efficient than treatment during the pressing, and the specific energy consumption for the both samples was approximately the same (W approximate to 7.5 kJ/kg). (C) 2014 Elsevier Ltd. All rights reserved.