Acoustic emission as a tool to assess the changes induced by pulsed electric field in apple tissue

The aim of this work was to analyse the acoustic and mechanical properties of pulsed electric field treated solid-like plant tissue as exemplified by apple fruits. The electrical conductivity of the untreated and PEF treated samples was measured as well. Additionally, an attempt to use the acoustic emission as a tool to assess the electroporation efficiency was done. Subjecting the apple discs to PEF treatment resulted in altered mechanical, electrical and acoustic properties. The compressive force registered at 15% strain was reduced by the PEF application up to 72.7% in comparison to the intact material. The number of acoustic events obtained by the contact method was the most suitable acoustic emission descriptor among other ones to differentiate the PEF treated and intact materials. The results of experiment and especially the PCA point out that the acoustic emission measured by the contact method can be a useful tool to evaluate both the disintegration efficiency and texture changes caused by the PEF application.