Dielectric Properties of Some Fresh Fruits and Vegetables at Frequencies of 2.45 to 22 GHz

ABSTRACT DIELECTRIC-CONSTANT and loss-factor values for potato, sweet potato, peach, watermelon, cantaloupe, and cucumber tissue at frequencies of 2.45, 11.7, and 22.0 GHz are reported, along with data on the moisture content, density, and soluble solids content of the fruit and vegetable tissues. Correlations were noted between the dielectric properties of the different tissue types and their moisture contents. The frequency dependence of the dielectric constant and the loss factor indicate that the dominant dielectric relaxation frequencies for fresh fruit and vegetable tissues lie either between 2.45 and 11.7 GHz or below this frequency range. Since this behavior is contrary to expectations, loss-factor values need to be checked by other measurement techniques.