Investigation of the Relationship between Moisture Content and Dielectric Constant of Wheat and Millet

Abstract

Moisture content has significant effects on most properties of agricultural products. One of these properties which are highly affected by moisture content is the dielectric constant of grains and seeds. Capacitive technique is a suitable method for moisture prediction of grains and seeds. In this study, a cylindrical capacitive sensor was used to determine the dielectric constant of Iranian wheat and millet. Results showed that dielectric constant of grains are highly dependent on the moisture content and frequency. Polynomial and hyperbolic regression models were developed between dielectric parameter and moisture content. Results showed that hyperbola model is more suitable and had higher value of R2 and lower value of SSE and RMSE. The best results were obtained at 500 kHz frequency for wheat and millet with R2 respectively equal to 0.9999 and 0.9982 in hyperbola regression.