Electroporation of Cell Membranes: The Fundamental Effects of Pulsed Electric Fields in Food Processing

Abstract

Using of pulsed electric fields (PEF) for killing of microorganisms in liquid foods is a promising new nonthermal food processing and preservation technology. However, to implement and optimize this technology, a good understanding of the actual mechanisms that govern microbial inactivation by this technique is required. Here, fundamentals of cell electroporation, which is considered as underlying phenomenon of food processing technology, are discussed. The whole process of the cell electroporation (food processing) by PEF is divided into the following four main stages: (1) building the transmembrane potential up by the applied external electric field, (2) creation of small metastable hydrophilic pores, when the transmembrane potential has been built up; (3) evolution of the pore population-the change in the number and/or sizes of poresduring an electric treatment; and (4) post-treatment stage consisting of the processes that take place after the electric treatment (leakage of intracellular compounds, pore shrinkage and disappearance, etc.). The current knowledge of the processes taking place during each of the above stages as well as the factors influencing them is discussed. Theoretical considerations are illustrated with the experimental data available.

Equivalent Pulse Parameters for Electroporation

“…In this case, a theoretical expression based on the model of electroporation is not explicitly stated. However, it might be possible to derive such an expression by using the equations for distribution functions for cell forming and resealing times, given in recent papers of Saulis [53] [54], and following the directions in the same papers. The four expressions (1)- (4) do not have any physical background that would relate them to electroporation meaning that they can also be used to describe the relation between amplitude and number of pulses.…”

Cell membrane electroporation-Part 2: the applications

“…It does not generate by-products and only mild heating occurs. During the last few years microbial and enzyme deactivation using electric pulses has been achieved in a variety of foods and beverages [15]. The effectiveness of the procedure depends on several parameters, e.g., pulse amplitude, duration, frequency and polarity, and temperature [15].…”

Irreversible electropermeabilization of the human pathogen Candida albicans: an in-vitro experimental study

“…Depending on treatment intensity the technique also causes serious degradative changes in bacteria and yeast cells, including an ionic punch-through effect and disruption of membranes, which lead to cell swelling, shrinkage, and lysis (Tsong 1991;Coster 2009). It can also be used as a successful food-preservation or sterilization technique against microbial contamination (Saulis 2010). There are, however, no current studies of the effects of co-application of antifungal drugs and PEF treatment as a faster, less toxic, and more effective way of treating fungal infections.…”