In this thesis, I investigate temperature changes in plant tissue during and after treatment with pulsed electric fields (PEF), with a particular focus on the occurrence of temperature inhomogeneities that may affect process uniformity and efficiency. Potato and carrot were selected as model tissues. The treatment was carried out using eight pulses of 100 µs duration at a frequency of 1 kHz and voltages of 500, 650, 800, and 1000 V. For each tissue–voltage combination, three replicates were performed (n = 3). Temperature was measured with fibre-optic sensors placed laterally to the electrodes at four positions, spaced approximately 3 mm apart. The collected data were analysed in MATLAB.
The results show that the absolute temperature rise increases nonlinearly with voltage and that heating is not fully homogeneous: differences between measurement positions become more pronounced with increasing voltage and are not negligible. Statistical analysis confirms that, in most comparisons, temperature differences between channels at the same voltage are statistically significant (p < 0.05), with some exceptions at lower voltages. Significant differences were also observed between voltages within the same channel.
A comparison of tissues indicates that in potato, temperature rises are greater but more consistent across the voltage range, whereas in carrot, at higher voltages, pronounced differences between channels emerge. These findings contribute to a better understanding of how tissue microstructure affects thermal responses during PEF treatment and provide a basis for optimising industrial processes where uniform and controlled treatment of biological materials is essential.
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