Effect Of Dielectric Barrier Discharge Research Articles

Synergistic Effects of Dielectric Barrier Discharge (DBD) Cold Plasma Pretreatment Combined with Microwave Drying on the Physicochemical and Functional Properties of Centella asiatica Leaves

Synergistic Effects of Dielectric Barrier Discharge (DBD) Cold Plasma Pretreatment Combined with Microwave Drying on the Physicochemical and Functional Properties of Centella asiatica Leaves

Reduction of antigenicity and emulsibility improvement of ovalbumin by dielectric-barrier discharge plasma treatment induced structure modification

The effects of Dielectric-Barrier Discharge (DBD) plasma treatment (40 kV, 1–4 min) on the structure, antigenicity and emulsibility of ovalbumin (OVA) were investigated. Plasma-induced structural changes of OVA were determined by SDS-PAGE, multi-spectroscopic, and LC-MS/MS analysis. Meanwhile, the reduction in antigenicity of OVA was evaluated by western blotting (WB) and enzyme-linked immunosorbent assay (ELISA) analysis. The results indicated effective elimination of the antigenicity of OVA was achieved after 4 min of plasma treatment. The immunoglobulin E (IgE) binding capacity of OVA was notably reduced by 90.80%, as evidenced by WB and ELISA analysis. Plasma-mediated oxidation led to the unfolding of OVA's structure, resulting in alterations to its conformational epitope, and the partial destruction of linear epitopes through polypeptide chain cleavage, thus contributing to the reduction in antigenicity. These findings were supported by the results of SDS-PAGE, multi-spectroscopic, and LC-MS/MS analysis. Furthermore, a significant increase (53%) in emulsifying ability and a one-fold improvement in emulsifying stability of OVA were achieved after 4 min of plasma treatment. The current study confirms that DBD plasma treatment not only reduces the allergenicity of OVA but also enhance its emulsibility through structural modification.

Effect of atmospheric dielectric barrier discharge treatment on the triboelectric charging properties of brominated Polyethylene granules

This paper aims to investigate the effect of dielectric barrier discharge (DBD) plasma treatment on the triboelectric charging properties of granular materials containing brominated flame retardants (BFRs). This work focuses on the impact of treatment time and the applied voltage frequency. Experiments were carried out on Polyethylene (PE) particles containing 40000 ppm of bromine (PE 4.6 % of Hexabromobenzene) and BFR-free PE. The DBD treated particles were then charged by triboelectric effect in a multi-cylinder device. The triboelectric charge acquired by each sample was quantified using a Faraday cage connected to an electrometer. The humidity of the ambient air ranged between 51 % and 60 % and the temperature varied from 16.5 °C to 19 °C during the experiments. Results show the significant influence of DBD treatment time on the triboelectric charging of brominated and non-brominated PE granules. In case of brominated PE, the particles acquire less charge than the non-brominated ones. Furthermore, it was found that the charge of DBD-treated particles is influenced by the applied voltage frequency. The observed variation in triboelectric behavior may be attributed to the changes in the roughness and wettability of the polymer surface caused by DBD.

Impact of pretreatment with dielectric barrier discharge plasma on the drying characteristics and bioactive compounds of jackfruit slices.

Hot-air drying is a popular method for preserving the production of jackfruit, but heat treatment damages its nutritional qualities. Cold plasma is one of the pretreatment methods used to preserve quality attributes of fruits before drying. In the present work, we studied the effect of dielectric barrier discharge (DBD) plasma on the drying characteristics, microstructure, and bioactive compounds of jackfruit slices with different pretreatment times (15, 30, 45, and 60 s), followed by hot-air drying at 50, 60, and 70 °C. A homemade DBD device was operated via three neon transformers. Optical emission spectrophotometry revealed the emitted spectra of the reactive species in DBD plasma, including the N2 second positive system, N2 first negative system, nitrogen ion, and hydroxyl radical. The results showed that the DBD plasma promoted moisture transfer and enhanced the drying rate, related to the changes in the surface microstructure of samples damaged by DBD plasma. The modified Overhults model was recommended for describing the drying characteristics of jackfruit slices. The contents of ascorbic acid, total phenolics, total flavonoids, total polysaccharides, and antioxidant activity in pretreated jackfruit slices were improved by 9.64%, 42.59%, 25.77%, 27.00%, and 23.13%, respectively. However, the levels of color and carotenoids were reduced. Thus, the bioactive compounds in dried jackfruit slices can be improved using the DBD plasma technique as a potential pretreatment method for the drying process. © 2023 Society of Chemical Industry.

Evaluation of the Effects of Dielectric Barrier Discharge Plasma on Candida albicans Strains: An in vitro Study

Background: Antifungal resistance is increasing, posing a challenge for treating candidiasis. Cold atmospheric plasma (CAP) is a potential alternative, but its association with traditional antifungals is poorly understood. Objectives: This study aims to evaluate the effects of dielectric barrier discharge (DBD) plasma on Candida albicans. Methods: In this in vitro study, C. albicans strains were irradiated with DBD plasma for 5, 10, and 15 minutes, both with and without nystatin. The number of colonies was counted, and the MTT method assessed Candida's survival. Data were analyzed with SPSS26. Results: This study showed that in both experimental groups, with and without nystatin, the lowest C. albicans cell viability was observed following a 10 minute DBD exposure within the groups subjected to plasma treatment (P < 0.001). The positive control group (nystatin without plasma exposure) exhibited a diminished count of viable cells in comparison to the group with 10 minute plasma irradiation without nystatin (P < 0.001). The 10 and 15 minute DBD plasma exposures, along with their positive control counterparts, demonstrated a statistically significant reduction in colony count compared to the 5 minute DBD exposure and the negative control groups (P < 0.001). Conclusions: Nystatin was more effective than DBD plasma irradiation in reducing C. albicans cell viability. When used in combination, 10 minute DBD plasma irradiation with nystatin was more effective than 5 or 15 minute irradiation times in reducing the survival rate of C. albicans.

Degradation Product of Sea Cucumber Polysaccharide by Dielectric Barrier Discharge Enhanced the Migration of Macrophage In Vitro.

This study investigated the effect of dielectric barrier discharge (DBD) on sea cucumber polysaccharide (SP-2) and evaluated its anti-inflammatory properties. The SP-2 was depolymerized by applying an input voltage of 60~90 V for 3~9 min. The features of the products were examined using high-performance gel permeation chromatography, HPLC-PAD-MS, and the Fourier transform infrared (FTIR) spectrum. The anti-inflammatory properties of the product were investigated by measuring nitric oxide (NO) release, ROS accumulation, and cell migration using RAW264.7 cells (LPS-induced or not-induced). The results showed SP-2 depolymerized into homogeneous and controllable-size oligosaccharide products. The depolymerized ratio can reach 80%. The results of the measurement of reducing sugars indicate that SP-2 was cleaved from within the sugar chain. The SP-2 was deduced to have a monosaccharide sequence of GlcN-Man-Man-Man-Man-Man based on the digested fragment information. The depolymerization product restrained the release of NO and the accumulation of ROS. By testing the RAW264.7 cell scratch assay, it was found that it enhances the migration of immune cells. DBD degradation of SP-2 leads to homogeneous and controllable-size oligosaccharide products, and this technique can be used for polysaccharide structure analysis. The depolymerized product of SP-2 has an anti-inflammatory capability in vitro.

The Stability, Rheological Properties and Interfacial Properties of Oil-in-Water (O/W) Emulsions Prepared from Dielectric Barrier Discharge (DBD) Cold Plasma-Treated Chickpea Protein Isolate and Myofibrillar Protein Complexes.

In order to increase the development and utilization of chickpea protein isolate (CPI) and improve the stability of myofibrillar protein (MP) emulsions, the effect of dielectric barrier discharge (DBD) plasma-modified CPI on the emulsifying properties of MP was investigated. Three different O/W emulsions were prepared using MP, MP + CPI complex, or MP + DBD-treated CPI complex as the emulsifier. Compared with the emulsion prepared from MP, the emulsifying activity index and stability of DBD-treated CPI and MP complex (MP + CPIDBD) were increased (p < 0.05) from 55.17 m2/g to 74.99 m2/g and 66.31% to 99.87%, respectively. MP + CPIDBD produced more stable emulsions with the lowest Turbiscan stability index (TSI) values for a given 3600 s. At shear rates from 0 to 1000-1, MP + CPIDBD-stabilized emulsions had higher viscosities, which helped to reduce the chance of aggregation between oil droplets. The optical microscope and particle size distribution of emulsions showed that MP + CPIDBD emulsions had the lowest droplet size (d4,3) and exhibited more uniform distribution. MP + CPIDBD emulsions had lower interfacial tension. DBD pretreatment increased the adsorbed protein content in the emulsion stabilized by MP + CPIDBD as compared to the MP + CPI complex and promoted the adsorption of CPI by higher ratios of adsorbed proteins as indicated by its intensity in SDS-PAGE. Scanning electron microscopy confirmed that the emulsion prepared from MP + CPIDBD had smaller particle size and more uniform dispersion. Therefore, using DBD-modified CPI could enhance the stability of MP emulsions.

An application of dielectric barrier discharge treatment to control gray mold growth on cut rose flowers

Cold atmospheric pressure plasma irradiation is an efficient method for decontaminating fruits and vegetables. The present study evaluates the effect of dielectric barrier discharge (DBD) cold plasma treatment on controlling gray mold (Botrytis cinerea Pers.), a destructive pathogen of cut roses (Rosa hybrida L. cv. Samurai). The ion leakage, relative water content (RWC), proline, chlorophyll, carotenoid, anthocyanin content, and discoloration of treated rose petals were measured. Experimental observation showed significant changes in ion leakage, RWC, and chlorophyll content at 20 kV for 8 min compared to the control. The same treatment induced significant changes in the proline content of the rose petals, but no statistical difference was observed in their anthocyanin and carotenoid contents compared to the control. The results indicated that gray mold growth was entirely suppressed by plasma irradiation at 20 kV for 4, 6, and 8 min and 15 kV for 8 min. Plasma at 10 kV for 8 min and 15 kV for 6 min suppressed 90% and 70% of the gray mold growth, respectively. It is noteworthy that plasma irradiation at 20 kV for just 4 min and at 15 kV for 6 min suppressed 100 and 70% of B. cinerea growth, respectively; however, plasma irradiation did not change the quality indices of rose petals. Overall, it can be said that cold plasma treatment by DBD has the potential to increase the shelf life of cut roses by suppressing gray mold development.

Influence of Dielectric Barrier Discharge Plasma Treatment on Corn Starch Properties

This study evaluated the effects of dielectric barrier discharge (DBD) plasma technology on some physicochemical and structural properties of corn starch. Amylose content, solubility, water absorption index, turbidity, structural relationships, and surface morphology were measured at 100, 200, and 300 Hz excitation frequencies and at 10 and 20 min exposure times. The plasma treatment at 200 Hz and 20 min promoted the most significant modifications in amylose content, solubility, the water absorption index, and surface morphology. Turbidity did not change significantly. The surface of the granule became smoother with the presence of pores. Slight changes were observed in the ordered structure of starch. Plasma changed several physicochemical properties, significantly decreasing the amylose to amylopectin ratio. Plasma treatment at 200 Hz is recommended to increase the amylopectin content in starches.

Experimental study on burning velocity, structure, and NOx emission of premixed laminar and swirl NH3/H2/air flames assisted by non-thermal plasma

This paper investigates the effect of dielectric barrier discharge (DBD) plasma on premixed laminar and swirl NH3/H2 flames by applying a coaxial DBD to the unburned gas mixture. We focused on analyzing the flame structure, burning velocity, lean blow-off limit, and NOx emission characteristics of premixed NH3/H2 flames in the presence and absence of plasma. The mechanism of plasma-enhanced burning velocity was revealed through kinetic simulations based on the CHEMKIN software. The results indicate that DBD plasma can reduce the laminar flame height and increase the laminar burning velocity (LBV). The chemical kinetic effect is dominant for the enhancement of LBV, while the effect of hydrogen generated from ammonia dissociation and ozone is relatively weak. DBD plasma can significantly change the structure of the swirl flames, while has a slight effect on extending the lean blow-off limits of the swirl flames. Finally, emission measurements indicate that DBD plasma increases the NOx emissions for both the premixed laminar and swirl NH3/H2 flames. This effect can be attributed to the reaction pathways involving of H and OH radicals for NOx formation. It is assumed that the effect of hydrogen and DBD plasma on stability and burning velocity is synergistic, while the effect of hydrogen and plasma on NOx emissions is competitive.

Effect of dielectric barrier discharge (DBD) cold plasma-activated water pre-treatment on the drying properties, kinetic parameters, and physicochemical and functional properties of Centella asiatica leaves

Centella asiatica L. (CA) is a medicinal plant that gained significant commercial and research interest because of its bioactive compounds, which have functional properties such as antioxidant activity. However, it must be dried before use to improve its shelf life and prepare it for food and pharmaceutical applications. Therefore, in this investigation CA leaves were pre-treated with blanching and cold plasma activated water (CPAW), followed by recirculatory hot air and vacuum drying at 40, 50, and 60 °C. Vacuum-drying took 150–720 min, while hot-air drying took 60–180 min to dry. Page and Logarithmic models best fit for leaf drying kinetics, according to AIC, with R2 between 0.966 and 0.999 and RMSE between 0.001 and 0.069. CPAW pre-treatment increased leaf quality more than blanching in vacuum drying. Drying leaves at 40 °C boosted antioxidants (4021.462 μg TE (g dw)−1 and 3.356 mg GAEAC (g dw)−1), TPC (35.049 mg GAE (g dw)−1), and TFC (311.274 mg QE (g dw)−1) and is recommended. Vacuum-drying with CPAW pre-treatment preserved leaf microstructure better than hot-air drying. This study illuminates CA leaf drying behaviour and allow mass production without damaging bioactive components. These results could be used as a roadmap for future technological advances that will make it possible to use the bioactive components of CA in food formulation.

Study of physico-chemical and antibacterial properties of DBD plasma treated ahimsa silk coated with natural active agent

This study investigated the effect of dielectric barrier discharge (DBD) plasma on the physicochemical and antibacterial properties of ahimsa silk fabric. The fabric was pre-treated for 1–5 min with DBD plasma in ambient air. The leaf extracts of Camellia sinensis (Green Tea) and Ocimum sanctum (Tulsi) were applied to the fabric to impart an antibacterial finish. Wettability, SEM, AFM, and tensile strength analyses demonstrated increased hydrophilicity and surface roughness with a slight reduction in mechanical strength. Both ATR-FTIR and XPS indicated an increase in the concentration of polar functional groups, such as -OH, -NH, -CHO, and -COOH, on the surface of the plasma-treated fabric. Antimicrobial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was evaluated using the agar plate method and modified Hohenstein test. The results verified the efficacy of plasma-treated fabric, with an approximately 93% reduction in E. coli and a 96% reduction in S. aureus growth that persisted even after three washing cycles. This study suggests that DBD plasma at atmospheric pressure can be used as an eco-friendly technology for modifying the surface of silk fabrics to promote better adherence of plant extracts to the fabric and subsequently enhance their microbial resistance.

Effect of Dielectric Barrier Discharge (DBD) plasma treatment in drinking water on physical, chemical, and biological parameters

This research aimed to determine the effect of Dielectric Barrier Discharge (DBD) plasma treatment on the physical, chemical, and biological parameters of drinking water. This research was conducted using a DBD plasma reactor with treatment time were 0, 5, 10, 15 and 20 minutes at AC voltage 5 kV. The results showed that there was an effect of DBD plasma treatment on the physical, chemical, and biological parameters of drinking water. The value of Total Dissolved Solid (TDS) and the number of bacteria in drinking water given DBD plasma treatment decreased with the lowest values of 148.33 ppm and 4 MPN/100 ml after sample treatment for 20 minutes. The pH value is stable, which is between 7-8. Based on this research, it can be seen that there is an effect of DBD plasma treatment on the physical, chemical, and biological parameters of drinking water.

A Meaningful Attempt: Applying Dielectric Barrier Discharge Plasma to Induce Polarization of Macrophages.

Macrophage polarization plays an important role in many macrophage-related diseases. This study was designed to preliminarily explore the effects of dielectric barrier discharge (DBD) plasma on the polarization direction and cell activity of macrophages with different phenotypes (ie, M0, M1, and M2). The M1 macrophage marker inducible nitric oxide synthase (iNOS) and M2 macrophage marker cluster of differentiation 206 (CD206) were detected by western blot (WB). The effects of DBD plasma on macrophage viability were analyzed by using a cell counting kit-8 detection kit. M0, M1, and M2 macrophages exhibited a decrease in iNOS expression and an increase in CD206 expression after the DBD plasma intervention. Additionally, the decrease in macrophage viability remained non-significant after initiating the intervention. DBD plasma can promote the transformation of M0 and M1 macrophages to M2 macrophages, and can further enhance the expression of the M2 macrophage phenotype marker CD206. Our study not only demonstrates the potential therapeutic value of DBD plasma for macrophage-related diseases, but it also provides a new direction for research to improve the treatment of macrophage-related diseases. © 2023 Bioelectromagnetics Society.

High efficiency and rapid treatment of naproxen sodium wastewater by dielectric barrier discharge coupled with catalysis

Pharmaceutical wastewater has the characteristics of high organic concentration and poor biodegradability, which will cause serious environmental pollution when discharged into water bodies. In this work, naproxen sodium was used to simulate pharmaceutical wastewater by dielectric barrier discharge technology. The effects of dielectric barrier discharge (DBD) and combined catalysis on the removal of naproxen sodium solution were studied. The removal effect of naproxen sodium was affected by discharge conditions, including discharge voltage, frequency, air flow rate and electrode materials. It was found that the highest removal rate of naproxen sodium solution was 98.5%, when the discharge voltage was 7000V, the frequency was 3333Hz, and the air flow rate was 0.3 m3/h. In addition, the effect of the initial conditions of naproxen sodium solution was studied. The removal of naproxen sodium was relatively effective at low initial concentrations as well as under the condition of weak acid or near-neutral solution. However, the initial conductivity of naproxen sodium solution had little effect on the removal rate. The removal effect of naproxen sodium solution was compared by using catalyst combined with DBD plasma and DBD plasma alone. x%La/Al2O3, Mn/Al2O3 and Co/Al2O3 catalysts were added. The removal rate of naproxen sodium solution reached the highest after adding 14%La/Al2O3 catalyst, which played the best synergistic effect. The removal rate of naproxen sodium was 18.4% higher than that without catalyst. The results showed that the combination of DBD and La/Al2O3 catalyst may be a promising method to remove naproxen sodium efficiently and quickly. And this method is a new attempt to treat naproxen sodium.

Effect of Dielectric Barrier Discharge Plasma against Listeria monocytogenes Mixed-Culture Biofilms on Food-Contact Surfaces

Listeria monocytogenes is a major foodborne pathogen. Various methods can be used to control biofilms formed by foodborne pathogens. Recently, the food industry has become interested in plasma, which can be used as a non-thermal technology with minimum changes to product quality. In this study, the effects of dielectric barrier discharge (DBD) plasma on L. monocytogenes mixed-culture biofilms formed on stainless steel (SS), latex hand glove (HG), and silicone rubber (SR) were investigated. DBD plasma effectuated reductions of 0.11-1.14, 0.28-1.27 and 0.37-1.55 log CFU/cm2, respectively. Field emission scanning electron microscopy (FE-SEM) demonstrated that DBD plasma cuts off intercellular contact and induces cell decomposition to prevent the development of biological membranes. It was confirmed that the formed biofilms collapsed and separated into individual bacteria. Our findings suggest that DBD plasma can be used as an alternative non-heating sterilization technology in the food industry to reduce biofilm formation on bacterial targets.

INFLUENCE OF DIELECTRIC BARRIER DISCHARGE ON BEET SEEDS GERMINATION

The effect of dielectric barrier discharge (DBD) treatment on the germination of beet seeds under different conditions was investigated. The emission spectra of the DBD plasma were measured under various operating conditions. It is shown that the main components of the emission spectra are nitrogen (N2) bands. The rotational (Tr) and vibrational (Tv) temperatures of the DBD plasma are determined from the N2 bands under different operating conditions. The dependences of the germination percentage of beet seeds at different time intervals of DBD treatment were obtained. The optimal time for treating beet seeds was determined.

Degradation of methylene blue aqueous solution using atmospheric pressure dielectric barrier discharge

Methylene blue (MB) is toxic to humans and aquatic animals, and its removal from aqueous solutions requires high power consumption and long processing times. To improve the effect of dielectric barrier discharge (DBD) treatment of methylene blue and increase the energy utilization rate. In this study, we employed a novel approach, using a cylindrical DBD reactor, to treat MB in aqueous solutions. We found several factors, including input voltage, aqueous solution flow rate, number of high voltage electrodes, electrode size, and inside diameter of the dielectric tube influenced the MB removal rates with DBD. Our experimental results indicate that the change of electrode parameters can effectively improve the removal rate of methylene blue in DBD plasma treatment. At the same time, electrode parameters can lead to medium layer change of energy consumption; hence, the influence of electrode parameters on energy utilization efficiency also has an optimal value.

Effects of dielectric barrier discharge cold plasma on structure, surface hydrophobicity and allergenic properties of shrimp tropomyosin

Effects of dielectric barrier discharge (DBD) cold plasma (CP) on structure, surface hydrophobicity and allergenic properties of tropomyosin (TM) in shrimp were investigated in this study. Results showed that the molecular weight of TM increased and the protein concentration decreased with CP treatment time increased. The content of free amino acids was increased by 74.7 % and the distribution of aromatic amino acids was altered. The content of α-helix was decreased by 69 % and the surface hydrophobicity increased by 57.8 % after 20 min treatment. Allergenicity analysis showed that the IgE binding capacity decreased by 96 % after 20 min treatment, and the degranulation indexes of KU812 cells like the β-HEX release rate, the intracellular calcium ion intensity, the release of histamine and inflammatory cytokines (IL-4, TNF-α) were decreased by 32.5 %, 31.0 %, 37.3 %, 51.7 %, and 70.2 %, respectively. The current study confirmed that DBD CP could reduce the TM allergenicity through structural changes.

Surface Wettability and Coating Performance of Plasma-Treated Wood-Based Composite Panels

The effect of dielectric barrier discharge (DBD) plasma treatment was studied on the surface characteristics and coating performance of transparent epoxy resin on the surface of particleboard (PB) and medium-density fiberboard (MDF). The plasma treatment was performed at three plasma energies (10, 15, and 20 kW) and three distances from the nozzle (10, 20, and 30 mm). Analyzing the samples by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated the changes of their chemical structure by means of the plasma treatment. The contact angle study showed a significant increase in surface wettability after plasma treatment with a pronounced effect observed by treatment parameters. The surface roughness was also significantly increased by the plasma treatment. The strength of the coating adhesion to the surface of the PB and MDF composite panels was also significantly improved by the plasma treatment, while no obvious trend was observed by treatment parameters. The highest adhesion strength of 2.03 MPa and 3.63 MPa were obtained by the PB and MDF samples, respectively, treated at a 10 mm nozzle distance and 15 kW plasma energy. The scratch resistance of the epoxy coatings showed a similar trend as the adhesion strength illustrating an inferior isolated surface of the coating after the plasma treatment.