Pulsed Electric Field Pre-treatment for Frying of Zucchini and Eggplant: Impacts on Oil Content and Color

Pulsed electric field (PEF) was used as a pre-treatment to investigate the oil intake and color of zucchini and eggplant slices after frying. Samples were PEF-treated at 1.0 kV/cm of electric field strength, and 1.0 kJ/kg (PEF1) and 3.0 kJ/kg (PEF3) of specific energy inputs. Frying was performed at 180 °C for 2 min. PEF3 treatment of zucchini reduced the oil content (> 32%) significantly compared to control samples whereas statistically same oil contents were obtained for eggplant. No significant differences were observed for the moisture contents of PEF-treated and untreated zucchini samples. On the other hand, moisture change was noticeable for the eggplant. Higher browning index values were calculated for PEF-treated vegetables, but this seemed to be highly dependent on specific energy inputs. Results revealed that PEF processing can be used before deep frying to reduce the oil content of zucchini with the formation of desired brown color.