Bio-impedance Measurements with Phase Extraction using the Kramers-Kronig transform: Application to Strawberry Aging

Fruit quality control is receiving increasing attention as an important application of bio-impedance measurements, which is a non-invasive technique. However, to effectively monitor fruit samples in the market, cheap and portable bio-impedance analyzers are needed while maintaining the accuracy of measurements over a wide frequency range. In this work, we report on the results obtained from a portable bio-impedance measuring device that relies on a modified Kramers-Kronig transform for calculating the phase from the measured impedance magnitude. This means that no actual hardware phase measurement takes place. The aging effect of strawberries is shown to be detected clearly via the change in impedance.