Abstract

The temperature dependence of effects exerted by pulsed electric fields (PEF) on the electrical conductivity and textural relaxation of potato tissue was investigated in the interval of 22–50 °C. The pronounced decrease of the characteristic electrical damage time τ with increase of both temperature T and electric field strength E was observed. Textural data reveal the essential temperature influence on tissue softening after the PEF treatment. The investigation of thermally induced damage at temperatures within 45–60 °C shows that effects observed below 50 °C are not related to any noticeable irreversible damage of the cellular membranes and reflect only effect of structural transitions in membranes on electroporation. It is of practical importance that PEF treatment under the mild thermal conditions (below 50 °C) allows to reach high tissue disintegration degree at moderate electric field strength (below 100 V/cm).

Keywords: Electroporation; Temperature dependence; Pulsed electric field; Texture; Characteristic damage time; Potato

Nomenclature

d

sample diameter (mm)

E

PEF intensity (V/cm)

E₀

empirical parameter (V/cm)

F

force (N)

h

Sample height (mm)

n

number of pulses

N

number of trains

R

universal gas constant, 8.314 (J K⁻¹ mol⁻¹)

t

time (s)

t_i

pulse duration (μs)

t_∞

effective relaxation time (s)

t_PEF

time of PEF treatment (s)

Δt

pulse repetition time (ms)

Δt_t

time pause between trains (s)

T

temperature (°C)

u_m

transmembrane potential (V)

u₀

voltage parameter (V)

ΔU

activation energy (kJ/mol)

Z

electrical conductivity disintegration index

Subscripts

E

electrical

T

thermal

Greeks

ρ

correlation coefficient

σ

electrical conductivity (S m⁻¹)

τ

characteristic damage time (s)

τ_∞

limiting characteristic damage time (s)

Abbreviation

PEF

pulsed electric fields

Article Outline

Nomenclature

1. Introduction

2. Materials and methods

3. Results and discussion

3.1. Conductivity disintegration index and electrical characteristic damage time

3.2. Textural relaxation of PEF-treated potatoes

3.3. Thermally induced damage of potatoes

4. Concluding remarks

Acknowledgements

References