Impedance spectroscopy study on irradiated potatoes

Potatoes of varieties Desiree and record were gamma irradiated with doses of 150 Gy, 300 Gy and 1000 Gy. Impedance readings were measured within one week of storage at 10 degree C using electrodes with sizes 2 mm in diameter, 30 mm in length and 30 mm apart. Altenating current with frequencies between 0.005 MHz to 1.0 MHz were applied to the electrodes and the reading were taken at 0, 90, 180 and 270 seconds after puncturing. No apparent effect of time after puncturing on the impedance reading was observed in irradiated samples. However in control samples, the reading was slightly increased up to 90 seconds of puncturing. The effect of irradiation on the impedance reading could clearly be seen in lower AC frequencies. At higher AC frequency however, the reading of both control and irradiated samples were not significantly differentiated. Complex plane plot impedance shows a semi-circular pattern. The peak of the graph and the real impedance value when the imaginary impedance is minimum were both increased by irradiation doses. As all of the impedance readings measured were affected by irradiation doses, it might be possible to develop and use the parameters for the detection purposes