We examined whether electrical impedance analysis could be used to monitor the state of sweet potatoes while they are being baked. Impedance measurements that used needle electrodes and adhesive pads as electrodes were compared to determine which was most suitable for measurements during heating. Adhesive pads were selected to measure the temporal changes in impedance of sweet potato because they can be applied non-destructively and can cope with changes in the shape of an object during heating. Adhesive pads were attached to the sides of sweet potato samples that were cut at both ends and were uniform in height, and changes in impedance were measured over time during baking. Cole-Cole plots shrank with heat treatment, suggesting that the impedance measurements were effective for monitoring the state change in sweet potatoes during baking.
