Abstract
The aim of the study was to evaluate the effect of pulsed electric field (PEF) pretreatment on drying kineticsand on color and textural changes in sliced parsnip and carrot. Cell disintegration index measured in parsnips after PEFpretreatment significantly differed from the ones measured for carrots and, consequently, the reduction of the time neededto dry both samples to a final moisture content up to 5% (wet basis). The drying time of the PEF pretreated parsnip wasreduced by up to 28% at 70 °C and by up to 21% at 60 °C in carrot, in comparison to untreated samples. The PEFpretreatment influenced the effective diffusivity of water into the samples going from 50 °C to 70 °C: in carrots it rangedbetween 1.61 × 10−10 and 3.04 × 10−10 (m 2 /s), although, in parsnip, it ranged between 1.97 × 10−10 and 3.06 × 10−10(m 2 /s). Also, PEF pretreatment influenced color changes: PEF pretreated dried carrots showed a significant (p < .05)reduction in lightness values (L∗) compared to untreated dried ones, although PEF pretreated parsnip had a significant (p< .05) increase in redness values (a∗). The PEF treatment did not affect the mechanical properties (p > .05) of carrot andparsnip dried at 50 and 60 °C, whereas at 70 °C a significant increase (p < .05) of the force required to cut both rootslices was detected. The choice of a PEF pretreatment of foods to be dried should be related to shorten the drying timeand to minimize the loss in quality properties mentioned above.