Mechanism of ohmic heating process

Both irradiation and microwave heating employ radiant energies which effect foods when their energy is absorbed, whereas ohmic heating raises the temperature of foods by passing an electrical current through the food.

When electrical current flows through a conductor, the motion of charges within the material results in agitation of molecules therein. This results in increased temperature.

Within metallic conductor, the moving charges are electrons; however, within food materials, the charges are usually ions or other charged molecules such as protein, which migrate to the electrode of opposite polarity.

Because heating occurs by internal energy generation within the conductor, the method results in a remarkably even distribution of temperatures within the material. Ohmic heating is alternatively called resistance heating or direct resistance heating. This due to food system serves as an electrical resistance.
Mechanism of ohmic heating process