Electrical impedance analysis of potato tissues during drying

We used electrical impedance spectroscopy (EIS) to explore the changes in the cell physiological status of potato tissues during hot air drying at 50-80 degrees C. The measured impedance data were analyzed using the modified Hayden model, which is an equivalent circuit model for cellular tissues. From the moisture content at the initial value to 1.0 (dry basis), focusing on the changes of equivalent parameters of the model, the cell membranes were apparently damaged by drying and heat stresses, and intracellular fluid leaked from the cells. At the moisture content less than 1.0, because of the destruction of cell structure, experimental data could not be fitted with the model, and due to the loss of moisture, the impedance magnitude increased rapidly as drying proceeded. These results showed the behavior of the cell physiological status of potato tissues during drying and the potential of EIS as a method for evaluating injuries to biological cells. (C) 2013 Elsevier Ltd. All rights reserved.