This paper presents the simulation results for dielectric barrier discharge (DBD) at atmospheric pressure in argon gas for different relative permittivity, granule shape, thickness layer, and granule diameter measurements for starch on the breakdown voltage. DBD is commonly utilized to generate cold plasma for starch modification. The electric field was computed using COMSOL Multiphysics 5.3a software. The breakdown voltage was calculated employing Paschen’s law for this electric field. The voltage was found according to the breakdown criterion for gap distance 0.2–1.0 cm, and then the Paschen curve could be plotted. The results show that the top electrode of the plasma system may be replaced with the parallel plate electrode by a mesh electrode with a bigger mesh size to achieve a lower breakdown voltage. In addition, increasing the relative permittivity and decreasing the thickness layer can reduce the applied voltage for plasma formation. When compared to the sphere and ellipsoid shapes, starch with a polyhedral granule shape requires a significantly lower voltage for breakdown. The starch granule diameter does not affect the breakdown voltage. These findings can be utilized to determine the optimal breakdown voltage for each type of starch modification, contributing to the construction of a high-efficiency plasma production system for starch modification.

This research aims to produce ozone using a dielectric barrier discharge to extend the shelf life and preserve the quality of mangosteen. The optimum condition of this system was a minimum breakdown voltage of about 6 kV_p-p, a resonance frequency of 224 kHz, and an oxygen flow rate of 2 L/min. The findings demonstrate that the maximal ethylene concentration value of treated fruit with ozone from oxygen flow rates 2 L/min lower than untreated fruit was approximately 11-fold. The L*, a*, b*, weight loss percentage, pericarp firmness value, and sensory evaluation were used to assess the quality of mangosteen. Compared to control fruit at 15 °C, fruit treated with ozone can have a prolonged shelf life of 9 days. Furthermore, assessing the quality and sensory score indicates that ozonation preserves the sensory quality of mangosteen. The weight loss percentage and pericarp firmness of fruit-treated ozone compared with the control were decreased by 3.34% and increased by 11.18 N, respectively. The sensory score of the fruit treated with ozone was higher than the control fruit, significantly different (p < 0.05).

An electric field in the dielectric barrier electrode system is necessary for ozone production because ozone is produced by the electric discharge of O2 under a high-intensity electric field. The gas discharge plasmas contain energetic particles, such as electrons, ions, atoms, and radicals. The recombination of the O atom and O2 in the plasma will form O3. In this paper, the dependence of DC electric field formation on electrode geometry and the gap between electrodes and dielectric materials were examined by using computational modeling. Thus, a set of electrode geometry, gap distance, and dielectric material were obtained for high-intensity and uniform electric field generation. The COMSOL Multiphysics software was used for the modeling. Among the electrode geometries of plate-plate, pin-plate and mesh-plate, the mesh-plate generated high-intensity and uniform electric field. In the modeling, dielectric materials, including quartz, mica, alumina, and water, were compared. The highest intensity of electric field occurred on the water surface. HIGHLIGHTS When the gap distance between two parallel electrodes is less than 100 mm, the electric field in the gap is constant, independent of the space A high-intensity and uniform electric field is generated in the gap between the dielectric and grounded electrodes when a fine mesh high-voltage electrode is utilized With the fine mesh electrode, the electric field is about two times higher than the conventional plate electrodes, whereas the electric field uniformity was about 90 %. Therefore the barrier discharge will be initiated with lower high voltage GRAPHICAL ABSTRACT