Effects of temperature on electrical parameters for‘Huoshi’ persimmon fruit

In order to investigate the effects of temperature on electrical parameters for ‘Huoshi’ persimmon fruit, variation of electrical parameters with temperature of intact ‘Huoshi’ persimmon fruit was studied over a frequency range from 100 Hz to 3.98 MHz with LCR meter and parallel plate electrode. Frequency and temperature characteristics of electrical properties were also illuminated by biology and electromagnetism theories. The results showed that fruit impedance, inductance and low frequency (f≤15.8 kHz) conductance varied in exponential form with the increase of frequency. As the fruit temperature rised from 10℃ to 40℃, fruit impedance decreased from 28% at 3.98 MHz to 38% at 1 kHz, the inductance 30% at 3.98 MHz to 38% at 1 kHz, while the capacitance increased from 43% at 3.98 MHz to 56% at 1 kHz, and the conductance had an increasing trend. Linearly correlation equations were built between fruit temperature and electrical parameters for the prediction of electrical parameter values at different temperatures. Frequency properties of fruit electrical parameters were attributed to the in-homogeneity of fruit structure, penetrating capacity variance of the electric field to the flesh and the variation of dominant dielectric loss factors at different frequency ranges, while the ionic conduction accounted for the temperature behavior of the electrical parameters.