On the modelling of the electrochemical phenomena at the electrode-solution interface of a PEF treatment chamber: Effect of electrical parameters and chemical composition of model liquid food

In this work, a Multiphysics model based on the Finite Element Method (FEM), was used to study the effect of different electrical parameters as well as chemical composition of the treatment medium on the metal release from the stainless steel (type AISI 316L) electrodes of a PEF chamber. A total of 15 processing conditions obtained by coupling different field strength (12-31 kV/cm) and total specific energy input (20-100 kJ/kg) were simulated with two model liquid food solutions with the same pH (7) and electrical conductivity (2 mS/cm at 25 degrees C) but different halides concentration. The results showed that the concentration of metallic elements (Fe, Cr and Ni) increased with decreasing the field strength applied or increasing the total specific energy input. These results were attributed to the predominant effect of the pulse frequency, rather than the applied voltage, on the average Faradaic current density values which, in turn, determine the extent of the metal release. Moreover, it was shown that the presence of halides in the composition of the processed product, may lower the breakdown potential and increase the Faradaic current density value which lead to an intense localized metal release from the electrode's surface. (C) 2015 Elsevier Ltd. All rights reserved.