Impact of Pulsed Electric Field Frequency on the Disintegration of Model Petal Tissue

The disintegration behavior of model petal tissue, rose, in response to frequency variations of a pulsed electric field was investigated by measuring the post-treatment electrical conductivity. Tissue suspended in a low conductive medium was exposed to a train of ten 10-μs pulses at 6 kV/cm, with frequencies ranging from 0.17 to 10 Hz. After the treatments, changes in conductivity were monitored for 30 min and used to calculate a disintegration index, Di, and specific energy input. The results were compared to field strengths (3–6 kV/cm), pulse lengths (10–130 μs), pulse numbers (10–70), and freeze–thaw treatment. Furthermore, the kinetics of conductivity during and after treatment were studied empirically and theoretically to gain a better understanding of frequency-induced disintegration. Reduced frequency in the pulse train of 10 at 6 kV/cm improved disintegration at 0.33 Hz, with the strongest disintegration at 0.17 Hz. At 0.17 Hz, the Di value (0.734 ± 0.067) was significantly greater than at 0.67 Hz, 1 Hz, and 10 Hz, but did not differ significantly from the pulse train of 20 at 10 Hz. The reduction to 0.17 Hz saved not just 10 pulses but also around 48% of the energy required for a comparable amount of disintegration. A thorough analysis of conductivity kinetics using model kinetic coefficients revealed that cellular disintegration during pulsation is the principal cause of the long-term effect. The current study shows that by reducing the frequency of the PEF treatment to 0.17 Hz, rose petal tissue can be efficiently disintegrated, suggesting the potential to enhance a variety of petal tissue extraction methods.