Moisture content and bulk density dependence of dielectric properties of safflower seed in the radio frequency range

The dielectric properties of safflower seeds were measured over a frequency range of 50 kHz to 10 MHz at moisture content in a range of 5.33-16.48% dry basis (d.b.) with bulk density which changed between 553.6 and 638.8 kg/m(3) using parallel-plate capacitor sample holder. Effects of the parameters such as moisture content, bulk density and frequency on the dielectric properties were studied. The dielectric constant and loss factor was greatly affected by the moisture content, frequency and bulk density. The moisture content was the most significant factor affecting the dielectric properties of safflower seed. The dielectric constant increased with an increase in the moisture content and bulk density, whereas it decreased with an increase in the frequency. The dependence of the dielectric constant on frequency and moisture content was more regular than that of the loss factor. The second and third-order polynomial equations were proposed to describe the existing relationship between dielectric properties and moisture content. Dielectric measurements provide new information concerning moisture content and bulk density dependent behaviour of dielectric properties of safflower seed in the radio frequency range that may be useful in sensing of the moisture content and dielectric drying applications. (c) 2006 Elsevier Ltd. All rights reserved.