Electroporation outcomes in plant tissue: Influence of structure and the choice of analytical method

The use of Pulsed Electric Fields (PEF) has been successfully implemented in the potato industry, but its application in the vegetable industry remains restricted due to limited knowledge on the behaviour of various plant tissue types in subsequent processing steps. This study investigates the heterogeneous effects of PEF across various plant tissues with differing structural complexities, including mostly homogeneous tissues (sweet potato), tissues with layers of different conductivity (red beetroot), tissues containing lignified areas (broccoli), and materials exhibiting structural heterogeneity (carrot, parsnip). PEF treatments were applied at electric field strengths ranging from 0.4 to 3.0 kV/cm, with specific energy inputs from 0.01 to 6.30 kJ/kg. Electrical impedance measurements were conducted before and after treatment, as well as after a 10-minute holding time to monitor the effects of water redistribution. Additionally, texture analysis was performed using compression measurements to assess the mechanical response of PEF-treated tissues. The results indicate that plant tissue complexity strongly influences the apparent uniformity of PEF treatment due to factors such differences in conductivity, as air pockets, and variations in water distribution. Additionally, tissue orientation relative to the electric field has a strong influence on treatment efficacy, especially for structurally inhomogeneous materials. The assessment methods show different sensitivities to changes in the tissue, depending on the applied treatment intensity.