Review on Electrical Conductivity in Food, the Case in Fruits and Vegetables

Abstract

Electrical conductivity in food and agricultural products is gaining attentions in response to ohmic heating and pulsed electric field processing, the newly emerging food processing technologies. Electrical conductivity of agricultural product is the ability of the products to conduct electric current. This paper is intended to review the electrical conductivity in foods in general and fruits and vegetables in particular. For this review to take its form, different articles, books and other possible sources have been reviewed, cited and acknowledged. So, this paper has been enriched by composition of the finding of different authors and researcher. Since measurement of electrical conductivity has number of application in agricultural products and food processing, methods of measuring this property is important. Measurement of electrical conductivity can be through dielectric analysis and electrical impendence spectroscopy measurement. In dielectric analysis high frequency area (100 MHz - 10 GHz) is used and this has an application in moisture determination and bulk density measurement. In electrical impendence spectroscopy, the range of frequency is from 100Hz to 10MHZ and is simple and easier techniques used to evaluate physiological status of various biological tissues. There are factors affecting electrical conductivity of agricultural products; electrical conductivity is reported by different authors to be increasing with temperature, field strength, and storage duration until the product is over ripe in case of fruits and vegetables. Plus, conductivity also found decreasing with increasing sugar content. The decrease in firmness of fruits and vegetables is related to increase in its conductivity. The nature of product and way of applying electricity is also other factors affecting conductivity. Electrical conductivity has number of application in foods, fruits and vegetable industries. However, still much work is expected for the utilization of its high potentials application.