Selective extraction from carrot slices by pressing and washing enhanced by pulsed electric fields

摘要

This work discusses efficiency of the pulsed electric field (PEF)-induced selective extraction of components from carrot slices by different combination of their washing and pressing treatment. The experiments were carried out using a laboratory filter-press cell, equipped with PEF-treatment system operated at moderate electric field strength (E=250-1000 V/cm) and at the constant pressure (P = 5 bars). The extraction was done by application of the washing-pressing (W-P) and pressing-washing-pressing (P-W-P) procedures to slices of different size. The decrease of the slice size was accompanied by enhancement of the extraction kinetics and rising of juice turbidity. The PEF application allowed to increase the juice yield and to increase the juice °Brix, however, these effects were noticeable only for larger slices with small degree of initial damage. The time of PEF application influenced the extraction kinetics, turbidity and °Brix of juice. The PEF application before W-P or P-W-P procedures allowed to reach maximum of the extraction rate and juice purity, but it required the highest energy consumption. The proposed method of PEF-assisted pressure extraction seems to be promising for selective extraction of different components from the soft cellular tissues.