Pulsed Electric Field Processing
Pulsed electric fields (PEF) can be applied to a range of products for a variety of purposes. It is used to induce a stress response in cells and soften tissue, improving the transfer of solutes in food products and inactivating microorganisms.
The principle behind the method is called electroporation, or electropermeabilisation. Very short electric pulses are applied to the product which create pores in the cell membranes.
A biological cell can be considered as a capacitor, filled with dielectric material and having a naturally occurring transmembrane potential. By exposing the cell to an external electric field generated between two electrodes, the accumulation of charges with opposite polarities on both sides of the membrane leads to an increase in the transmembrane potential. When a critical value of around 1 V is exceeded (the value depends on the initial thickness of the cell membrane as well as on its barrier functional properties) the membrane breaks down and pores, or holes, are created. The electric field also leads to local conformational changes in the membrane’s bilayer structures and rapid electrical breakdown of cell membranes can occur.
Depending on the cells, the surrounding conditions and the intensity of the treatment, electroporation can be reversible or irreversible. In the food industry, reversible electroporation is useful for creating structural changes, especially tissue softening. Irreversible treatment results in the inactivation of microorganisms. So PEF technology has broad range of applications, some of which will be demonstrated in the next Step.