Rapid non-contact relative permittivity measurement of fruits and vegetables using magnetic induction spectroscopy

The characteristic bio-impedance spectra of a biological sample can provide important information about its cellular structure, and further, infer useful information about the physical and chemical condition of the sample. In this paper, we present the background detail of a magnetic induction spectroscopy system for non-contact bio-impedance measurements, and some results using this system to obtain the relative permittivity spectra of a range of fruit and vegetable samples, over a frequency range from 160 kHz to 2.5 MHz. Relative permittivity is found to decrease with respect to frequency for each sample tested. This shows clear evidence of dispersion occurring within the samples across the investigated bandwidth.