Dielectric Properties of Fruits and Vegetables as a Function of Temperature and Moisture Content Dielectric Properties of Fruits and Vegetables as a Function of Temperature and Moisture Content

Abstract

The relative permittivity, ε’ and relative loss factor, ε” of apple, chervil, mushroom, parsley, and strawberry were measured at 2800 MHz, with a cylindrical TM012 perturbation cavity. The measurements were made over a range of moistures and temperatures. The results show that the relative loss factor has a maximum value at an intermediate moisture content for all the fruits and vegetables investigated. The relative permittivity decreases with increasing temperature at a high moisture content, but at intermediate moisture contents ε’ increases with temperature. Equations were developed for interpolation of the relative permittivity and the loss factor.