Acoustic and mechanical properties of carrot tissue treated by pulsed electric field, ultrasound and combination of both

Abstract

Abstract: Both ultrasound (US) and pulsed electric field treatment (PEF) allow achieving similar technological aims. Their application can for instance improve food preservation or enhance heat and mass transfer based processes. However, the mechanisms of action and the impact of these technologies on the structure of biological systems are different. Based on the knowledge concerning the behaviour of tissue subjected to pulsed electric field or sonication it can be assumed that the combination of these techniques can be beneficial. Therefore the aim of this study was to analyse the impact of pulsed electric field, ultrasound and combined (pulsed electric field followed by ultrasound or ultrasound followed by pulsed electric field) treatment on electrical conductivity, intercellular structure, mechanical and acoustic properties of plant tissue as exemplified by carrot samples. Performed research proved that the mechanism of action and the consequences of US treatment are different in comparison to pulsed electric field application. The efficiency of sonication cannot be evaluated on the basis of electrical conductivity like it is usually done in the case of electroporation efficacy assessment. The results concerning mechanical and acoustic properties also indicate that pulsed electric field causes higher alterations of intercellular structure than ultrasound. In general the utilization of US prior to PEF treatment can enhance the effectiveness of electroporation.