Radio-frequency dielectric relaxation behavior of selected vegetable tissues: Spectra analysis with logarithmic derivative method and simulation with double-shell model

Abstract

The dielectric relaxation behaviors in the radio-frequency range, where β- relaxation is predominant, of flesh tissues of several vegetables are studied in this work. By taking advantage of the logarithmic derivative method, three sub -β- relaxations were revealed for all vegetable tissues under study, and their relaxation characteristics were accurately determined. The relaxation behaviors were further simulated by means of the double-shell model. With reasonable values of involved morphological and physiological parameters, fairly satisfying simulations were achieved, where the simulated relaxations have consistent relaxation times to those of the measured relaxations. The simulation suggests that the low-frequency sub -β- relaxation arises from polarization of plasma membrane, while the middle- and high-frequency sub -β- relaxations are due to interfacial polarization at interfaces of tonoplast/protoplasm and cell sap/tonoplast, respectively.