Abstract
ABSTRACT The objective of this study was to investigate the effects of pulsed electric field (PEF) treatment on compressing behavior and texture of potatoes. Textural data reveal that PEF treatment can cause enlargement of pressure for the same level of deformation. The fracture pressures Pc were approximately the same for both untreated and PEF‐treated specimens, Pc ≈ 4.5 ± 0.4 MPa. The maximal pressure Pm, at which the time of the pressure‐induced rupture of intact cells should be of the same order of magnitude as the time of fluid expression from damaged cells, was estimated as Pm ≈ 6 MPa. For a small pressure (P = 1 MPa) to obtain a similar deformation (ε = 0.15) requires pressing time t ≈ 3.5 h for untreated tissue and t ≈ 70 s for PEF‐treated tissue. Measured electrical conductivity was practically constant and exhibited no noticeable time dependence during constant pressure stage in untreated samples, while the conductivity of PEF‐treated specimens decreases in the course of pressing.PRACTICAL APPLICATIONSSolid–liquid expression is widely used in the food industry for the extraction of fruit and vegetables. Efficiency of this process can be increased by different pretreatment methods. Pulsed electric field (PEF) has been shown to be good for juice yield intensification and for improving the product quality in juice production. It is of great interest for process purposes to study texture proprieties of PEF‐treated and untreated tissues, because texture is one of the most important quality attributes of food products. This work also gives new information about the mechanism of the PEF‐induced damage and expression from tissues. The obtained results may be helpful for development of new engineering concepts based on PEF‐enhanced extraction at comparatively low pressures and moderate time of processing.
Published Version
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