Effect of pulsed electric field treatment on cell-membrane permeabilization of potato tissue and the quality of French fries

The effect of pulsed electric field (PEF) treatment on the cell membrane permeabilization of potato tissue and the quality of French fries was investigated. Pulses with an electric field strength of 0.5, 1.5, and 2.5 kV/cm and a width of 20 μs were applied to the potato. PEF treatment permeabilized the membrane of potato cells. The magnitude of cell-membrane permeabilization was estimated by ion leaching and biological impedance tests and verified by microscopic observation. As the PEF field strength increased, the accumulation of neutral red dye decreased due to increased cell rupture. The index Z-values (relative cell membrane breakdown values) for 0.5-, 1.5-, and 2.5-kV/cm PEF-treated samples were 0.01, 0.28, and 0.52, respectively. PEF treatment at 2.5 kV/cm reduced the cutting force of potatoes by 33%; it also increased the degree of the crispness of French fries by 64% and decreased crude fat content by 28%. The total reducing sugar content was decreased by PEF treatment, which could be attributed to increased lightness and yellowness after frying. Therefore, PEF treatment improved the quality of French fries by increasing crispness, improving color, and reducing crude fat content.