  We present results of numerical and experimental investigation of the
electric breakage of a cellular material in pulsed electric fields (PEF). The
numerical model simulates the conductive properties of a cellular material by a
two-dimensional array of biological cells. The application of an external field
in the form of the idealised square pulse sequence with a pulse duration
$t_{i}$, and a pulse repetition time $\Delta t$ is assumed. The simulation
model includes the known mechanisms of temporal and spatial evolution of the
conductive properties of different microstructural elements in a tissue. The
kinetics of breakage at different values of electric field strength $E$,
$t_{i}$ and $\Delta t$ was studied in experimental investigation. We propose
the hypothesis for the nature of tissue properties evolution after PEF
treatment and consider this phenomena as a correlated percolation, which is
governed by two key processes: resealing of cells and moisture transfer
processes inside the cellular structure. The breakage kinetics was shown to be
very sensitive to the repetition times $\Delta t$ of the PEF treatment. We
observed correlated percolation patterns in a case when $\Delta t$ exceeds the
characteristic time of the processes of moisture transfer and random
percolation patterns in other cases. The long-term mode of the pulse repetition
times in PEF treatment allows us to visualize experimentally the macroscopic
percolation channels in the sample.
