Time-domain dielectric spectroscopy of apples

The ELF (extremely low frequency) dielectric properties of apples are measured using time-domain dielectric spectroscopy. A voltage step is applied to the outer pair of a four-electrode array inserted in an apple. voltages in the vicinities of the electrodes and the current flowing through the apple are sampled under microcomputer control during polarization and depolarization. Fourier transformation of the variation of the bulk conductance with time yields the dielectric spectrum. Approximate power-law behavior is observed for the capacitance and dielectric loss for 1<f<1000 Hz. At higher frequencies little variation is observed. Below 1 Hz it is unclear whether the spectrum is flat or power-law with a small exponent. These results are similar to those observed for other complex plants and animal organs