Pulsed electric field enhanced drying of potato tissue

The influence of pulsed electric field (PEF) treatment on convective drying of potato tissue was investigated. The drying experiments for potato disks were done in the interval of drying temperatures 30-70 degrees C. The effects of pre-treatment before drying and PEF treatment in the course of the drying are discussed. The temperature dependencies of moisture effective diffusion coefficient D(eff) for intact, PEF-treated and freeze-thawed potato tissues are compared. It is shown that D(eff) is a function of the conductivity disintegration index Z(sigma). The moisture effective diffusion coefficient D(eff) is sensitive to the pre-treatment procedure, and the highest values of D(eff) are always observed for freeze-thawed pretreated samples. The data show that thermal pre-treatment of samples at high temperatures (T = 70 degrees C) has practically no beneficial effect on the drying rate, though the same thermal pre-treatment at mild temperatures (T = 50 degrees C) increases the moisture effective diffusion coefficient Deff and gives an effect that is comparable with that for the PEF pre-treated samples. (c) 2005 Elsevier Ltd. All rights reserved.