Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 13, 2007
Publication Date: December 22, 2007
Citation: Zhang, H.Q. 2007. Electrical properties of foods. In: Food Engineering, Barbosa-Canovas GV editors. Encyclopedia of Life Support Systems (EOLSS). Developed under the Auspices of the UNESCO, Eolss Publishers. Oxford, UK. 1:115-125.
Foods, especially liquid foods, conduct electricity. Unlike in metals, the charge carriers in foods are ions, instead of electrons. Under normal applications, ions carry the charges as the mass of ions moves along the electrical field. The concentration and mobility of ions determine the electrical conductivity. Temperature and other ingredients in the foods affect the ion mobility. Under extreme electric field, electron-hopping takes place between the ions or molecules. This is the precursor of dielectric breakdown of foods, in which case an arc is the observed result. Electrical properties are important in processing foods with Pulsed Electric Fields, Ohmic Heating, Induction Heating, Radio Frequency, and Microwave Heating. These properties are also useful in detection processing conditions or in determining the quality of foods.