Pulsed electric fields processing of apple tissue: Spatial distribution of electroporation by means of magnetic resonance imaging and computer vision system

The optimal application of Pulsed Electric Fields (PEF) technology, used by food industry to assist mass transfer processes, depends on the effectiveness of the induced electroporation. The present work aimed at exploring the application of Magnetic Resonance Imaging (MRI) combined with Computer Vision System (CVS) analysis to assess the spatial distribution of electroporation in apple tissue. PEF-treated apple samples were compared with Dipping (Dip) and Vacuum Impregnation (VI) to gain insight into the spatial distribution of mechanisms that lead to microstructural modifications over time. CVS showed that electroporation modified heterogeneously apple microstructure, causing enzymatic browning unevenly across the samples. MRI transverse relaxation times (T2) maps and longitudinal relaxation times (T1)-weighted images throughout apple tissue confirmed the inhomogeneous distribution and extent of the cell disruption, along with the release of intracellular content toward the external solution. Industrial relevance: The novel applications of pulsed electric fields require fast and reliable methods to detect and estimate the breakage of the membranes integrity in order to boost their industrial adoption and optimization. The present study provided analytical tools able to monitor the spatial distribution of electroporation in plant tissue samples within minutes and consequently to speed up and improve the assessment of different PEF treatments.