Measurement of Date Fruit Moisture Content by Use of a Nondestructive Dielectric Method

Developing a rapid، nondestructive and reliable method to measure moisture content of date fruit is of interest in pre- and post-harvest processes of this valuable product. Throughout this research، by putting date palm fruits (cv. Mazafati) in a parallel plate capacitor، the sinusoidal alternative voltage in the frequency range of 1 to 100 MHz was exerted to the dates and the response of the circuit recorded while using a spectrum analyzer. Then، the relation between the power consumption of the system at different frequencies and the moisture content of the samples was studied and modeled using Multiple Linear Regression (MLR) analysis. The results indicated that by using the entire frequencies within the range of 1-100 MHz، the moisture content of date palm fruits could be predicted by a coefficient of determination (R2p) of 0. 956، a Root Mean Squares Error of Prediction (RMSEP) of 5. 28% and a Standard Deviation Ratio (SDR) of 2. 97. By analysis of regression coefficients، some six effective frequencies in moisture content estimation were selected and used for building up the simpler models. The same similar results were obtained when compared with modeling by the entire range of frequencies.