_applied sciences_  
_Article_  
The Advancement and Utilization of Marx Electric Field  
Generator for Protein Extraction and Inducing  
Structural Alterations  
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pulses, as well as other parameters of the output pulses, should be selected based on their applicability in these experiments. Exponential or square pulses are generally used for the electroporation of cells. The use of square pulses is particularly advantageous under laboratory conditions, as they allow the precise control and reproducibility of the relevant electrical parameters, such as pulse length and amplitude [5; 6; 7; 8]. However, to generate this pulse shape, capacitors with relatively high capacitance and quite complex switching units should be used. Blumlein or transmission line pulse generators naturally do not have this problem, as the energy is completely discharged during a single pulse [9; 10]. However, these generators are limited in terms of maximum voltage and can only generate short pulses of up to one microsecond in duration [5; 11]. Exponentially decaying pulse generators with capacitor discharge circuits are widely used due to their simplicity and cost-effectiveness. Various types of these electric field generators have been used in food processing, such as transformer-based generators [12], gas-filled switch-based generators [13], and cascaded solid-state generators [14]. Key features of these generators include the maximum voltage and current amplitude as well as the characteristic time constant (\(\tau\)), which indicates the time required to reach approximately 37% of the initial potential drop. The Marx generator, which consists of a number (N) of capacitors (C) and switches, is one of these types of generators [15; 16; 17]. The advantage of the Marx generator is that a relatively low voltage source is used to generate the high voltage in output. During operation, the capacitors are charged in parallel and then discharged in series via the load (\(Z_{\text{L}}\)) by switching on all switches simultaneously. Rise time, fall time, voltage gain (the ratio between the peak value of the output voltage waveform and the input charge voltage of all stages), and full width at half maximum (FWHM) are the defining parameters of an electrical pulse. Depending on the application, the pulses should have certain ranges of the parameters mentioned [18]. The maximum voltage and the maximum current applied to the load \(Z_{\text{L}}\) depends on the charging voltage of the capacitors, the number of capacitors, and the internal impedance (\(Z_{\text{in}}\)) of the device. The width of the electrical pulse also plays an important role. Some studies reported higher inactivation rates when wider pulses were applied [19; 20]. On the other hand, [PERSON] et al. reported that for pulses of the same specific energy, shorter pulses applied at higher field strengths were more effective in microbial inactivation than wider pulses at lower field strengths [21]. Furthermore, the increased efficiency at longer pulse durations was shown to correlate with the predictions of large cell theory [22]. Since the electroporation of the cell membrane occurs when the induced transmembrane potential exceeds a threshold value (typically about 0.2-1.0 V), the duration of the pulse can in no case be shorter than the minimum time required to reach the transmembrane potential that is specific for the cell type [23]. Therefore, for different applications, for example, protein extraction during microalgae cultivation [24; 25] or the change in structural properties of casein micelles [26], various ranges of PEF duration are required. For exponentially decaying pulse generators, the FWHM depends on the time constant, which is calculated according to the equation \(\tau=\mid Z_{\text{L}}+Z_{\text{in}}\mid C/\text{N}\).