Effect Of Plasma-activated Water Research Articles

Plasma-activated water improves the accessibility of chitinase to chitin by decreasing molecular weight and breaking crystal structure

Chitooligosaccharides, the hydrolysis products of chitin, have superior biological activities and application value to those of chitin itself; however, the ordered and highly crystalline structure of chitin renders its degradation by chitinase difficult. Herein, the effects of plasma-activated water (PAW) pre-treatment on the physicochemical properties, crystal structure, and enzymatic hydrolysis of chitin were investigated. The hydrolysis of PAW-pre-treated chitin (PAW activation time of 5 min) using chitinase from Vibrio harveyi (VhChit2) yielded 71 % more reducing sugar, compared with that from untreated chitin, with the degree of chitin hydrolysis increasing from 13 % without pre-treatment to 23 % post-treatment. Moreover, the amount of VhChit2 adsorbed by chitin increased from 41.7 to 58.2 mg/g. Fourier transform infrared spectrometry revealed that PAW could break the β-1,4-glycosidic bonds of chitin (but had no effects on the hydrogen and amido bonds), thereby decreasing the molecular weight and crystallinity of the polysaccharide, which caused its structural damage and enhanced its enzymatic hydrolysis by chitinase. Consequently, PAW pre-treatment can be considered a simple, effective, and environmentally-friendly method for the biotransformation of chitin as its easier hydrolysis yields high-value products.

Mechanism of plasma-activated water promoting the heat-induced aggregation of myofibrillar protein from silver carp (Aristichthys Nobilis)

This work aimed to explore the underlying mechanism of plasma-activated water (PAW) promoting the heat-induced aggregation of myofibrillar protein (MP). The results of particle size and atomic force microscope indicated that PAW accelerated the aggregation of MP with PAW60 showing the densest and most homogeneous crosslinking morphology. Raman spectroscopy showed that about 4.11% of the α-helix in PAW60 changed to β-sheet during heating. The effects of PAW on the oxidation of MP were assessed in terms of sulfhydryl, disulfide bonds, carbonyl content and surface hydrophobicity. The amino acid composition revealed that the content of tyrosine dropped from 45.43 mg/g of PAW0 to 37.35 mg/g of PAW240, indicated that tyrosine in MP was converted to dityrosine by PAW. These results indicate that PAW promotes the oxidation of MP and further changes in intra- and inter-molecular interactions, which provides a theoretical basis for PAW promoting thermal aggregation of MP.

Effect of plasma-activated water (PAW) soaking on the lipid oxidation of sardine (Sardina pilchardus) fillets

The efficacy of plasma-activated water (PAW) as a chemical-free and environmentally friendly preservative has been documented for a variety of foods, but the onset of lipid oxidation induced by plasma-reactive species has been less extensively studied. In this work, global indices (peroxide value, UV specific absorbance) and direct analytical determinations of volatile and non-volatile oxidation products were performed on sardine lipids extracted from fish fillets immersed in PAW (treatments) and distilled water (controls) for 10–30 min. Evidence of PAW-induced lipid oxidation was provided by higher UV specific absorbances and higher levels of C5-C9 secondary volatile oxidation products in the treated samples. However, the degree of fatty acid oxidation was not sufficient to cause a significant reduction in nutritionally valuable eicosapentaenoic acid and docosahexaenoic acid. Twelve cholesterol oxidation products (COPs) were identified in the sardine lipids, but no significant differences in total COPs content were found between PAW processed and control samples.

Effect of Plasma-Activated Water (PAW) Generated With Various N2/O2 Mixtures on Soybean Seed Germination and Seedling Growth

Effect of Plasma-Activated Water (PAW) Generated With Various N₂/O₂ Mixtures on Soybean Seed Germination and Seedling Growth

Assessment of lipid oxidation and microbial decontamination of sardine (Sardina pilchardus) fillets processed by plasma-activated water (PAW)

Plasma activated water (PAW) is emerging as a mild and environmentally friendly technology for microbial and chemical decontamination of food. The aim of this work was to evaluate the degree of oxidation of lipids of sardine tissue treated by PAW generated with a pulsed corona discharge. The effect of PAW on the natural microflora of the fish was also evaluated. Under the adopted experimental conditions, PAW was able to reduce the number of mesophilic aerobes and Pseudomonas spp. by 0.22 and 0.20 log units, respectively, but no increase in shelf life was observed at chilling temperatures compared to water washing. A loss of polyunsaturated fatty acids (PUFAs) and an increase in volatile oxidation products derived from the cleavage of PUFA hydroperoxides were observed at the longest treatment duration. Twelve cholesterol oxidation products (COPs) were identified in sardine lipids, but no significant differences in total COPs content were observed between PAW processed and control samples. Free radical mediated oxidation pathways led to the most abundant COPs, but a significant contribution of non-radical pathways was also observed. Further studies are needed to better understand the low efficiency of PAW in microbial decontamination of proteinaceous materials.

Effect of plasma-activated water on the biofilm-forming ability of Salmonella enterica serovar Enteritidis and expression of the related genes

In recent years, microbial decontamination with plasma-activated water (PAW) has attracted a lot of research attention in the field of food industry. Despite several studies showing that PAW effectively inactivates planktonic bacteria, few studies have been conducted on biofilms. The present study was, therefore, designed to evaluate the effect of PAW on the biofilm formation characteristics of Salmonella Enteritidis. Comparing the expression patterns of biofilm-related genes in PAW-treated and non-treated planktonic and biofilm cells provided insight into how PAW regulates this process. The results showed that a 30-minute exposure to PAW at room temperature significantly reduced S. enteritidis planktonic cells. This exposure resulted in a decreased expression of the genes involved in the early stages of biofilm formation (csgD, agfA, fimA, lpfE, and rpoS), and an increased expression of the csrA gene in S. enteritidis planktonic cells. These results indicated the inhibitory effect of PAW on the biofilm formation process in S. enteritidis. Results of the initial attachment assay confirmed these findings, where, after 6 h, the number of PAW-treated cells attached to the stainless steel surfaces were significantly lower than non-treated ones. Furthermore, biofilm development assay revealed that the number of PAW-treated biofilm cells were significantly lower than non-treated ones after 24 h incubation at 37 °C. These findings were confirmed by measurements of the major components of biofilm i.e., extracellular DNA (eDNA), protein and carbohydrate. The amount of these components in 24-hour biofilms produced by PAW-treated S. enteritidis cells was significantly lower than that of non-treated cells. PAW's treatment on preformed 24-hour biofilms for 30 min led to a decrease in the expression of genes involved in quorum sensing and cellulose synthesis (csgD, bapA, adrA, luxS and sdiA) and an increase in the expression of the csrA gene. This treatment also reduced the number and metabolic activity of biofilm cells compared to non-treated biofilm cells. In total, the present study demonstrated that PAW has an inhibitory effect on the process of biofilm formation in S. enteritidis and hence, the food industry should pay special attention to PAW as a promising treatment to eliminate bacterial biofilms.

Enhancing seed germination and growth parameters of cauliflower (Brassica oleracea, variety Botrytis) using plasma-activated water

The effects of plasma-activated water (PAW), generated through atmospheric pressure air gliding arc discharge, on the germination and growth parameters of cauliflower (Brassica oleracea, variety Botrytis) seeds have been investigated. Results demonstrate significant influences of PAW on seed germination characteristics and seedling growth parameters. Increasing the exposure time of seeds to plasma from 0 to 20 min leads to a notable increment in the water uptake rate, ranging from approximately 94.0% to 115.0%. Furthermore, the physio-chemical characteristics of PAW are examined, revealing its transformation into acidic solutions, accompanied by rising electrical conductivity, oxidation-reduction potential, total dissolved solids, and nitrate and nitrite concentrations with longer treatment times. Notably, applying PAW for 10–15 min results in higher seed germination and seedling growth. Comparative experiments involving PAW and control water demonstrate enhanced germination, increased root and shoot lengths, and elevated chlorophyll content. However, prolonged exposure to PAW shows adverse effects. Cauliflower plants treated with 10 min and 15 min of PAW exhibit the highest chlorophyll concentration, root and shoot lengths. These findings underscore the potential of PAW to improve seed germination and plant growth, emphasizing the importance of adjusting the plasma treatment period for each specific seed.

Effects of Plasma-Activated Water via Different Gas Treatments on Coffee Ground Decomposition

Effects of Plasma-Activated Water via Different Gas Treatments on Coffee Ground Decomposition

Effect of plasma-activated water on peanut seed germination and vegetative growth in a hydroponic system

Effect of plasma-activated water on peanut seed germination and vegetative growth in a hydroponic system

An Effective Sanitizer for Fresh Produce Production: In Situ Plasma-Activated Water Treatment Inactivates Pathogenic Bacteria and Maintains the Quality of Cucurbit Fruit.

The effect of plasma-activated water (PAW) generated with a dielectric barrier discharge diffusor (DBDD) system on microbial load and organoleptic quality of cucamelons was investigated and compared to the established sanitizer, sodium hypochlorite (NaOCl). Pathogenic serotypes of Escherichia coli, Salmonella enterica, and Listeria monocytogenes were inoculated onto the surface of cucamelons (6.5 log CFU g-1) and into the wash water (6 log CFU mL-1). PAW treatment involved 2 min in situ with water activated at 1,500 Hz and 120 V and air as the feed gas; NaOCl treatment was a wash with 100 ppm total chlorine; control treatment was a wash with tap water. PAW treatment produced a 3-log CFU g-1 reduction of pathogens on the cucamelon surface without negatively impacting quality or shelf life. NaOCl treatment reduced the pathogenic bacteria on the cucamelon surface by 3 to 4 log CFU g-1; however, this treatment also reduced fruit shelf life and quality. Both systems reduced 6-log CFU mL-1 pathogens in the wash water to below detectable limits. The critical role of superoxide anion radical (·O2-) in the antimicrobial power of DBDD-PAW was demonstrated through a Tiron scavenger assay, and chemistry modeling confirmed that ·O2- generation readily occurs in DBDD-PAW generated with the employed settings. Modeling of the physical forces produced during plasma treatment showed that bacteria likely experience strong local electric fields and polarization. We hypothesize that these physical effects synergize with reactive chemical species to produce the acute antimicrobial activity seen with the in situ PAW system. IMPORTANCE Plasma-activated water (PAW) is an emerging sanitizer in the fresh food industry, where food safety must be achieved without a thermal kill step. Here, we demonstrate PAW generated in situ to be a competitive sanitizer technology, providing a significant reduction of pathogenic and spoilage microorganisms while maintaining the quality and shelf life of the produce item. Our experimental results are supported by modeling of the plasma chemistry and applied physical forces, which show that the system can generate highly reactive ·O2- and strong electric fields that combine to produce potent antimicrobial power. In situ PAW has promise in industrial applications as it requires only low power (12 W), tap water, and air. Moreover, it does not produce toxic by-products or hazardous effluent waste, making it a sustainable solution for fresh food safety.

Effect of Plasma-Activated Water and Direct Plasma on Enterococcus faecalis Bacteria for Disinfection of Tooth Root Canal

This research studies the effect regarding two plasma types, plasma jet and plasma-activated water (PAW), on tooth root canal bacteria Enterococcus faecalis. The plasma jet works with argon gas, and it is generated by a power supply that operates at alternating high voltages in the form of a sinusoidal wave with peak-to-peak value of about 12 kV at a frequency of 30 KHz and its power is about 200 watts. This plasma was utilized directly to treat the tooth canal and indirectly by activating the water that was used later for treating the Enterococcus faecalis bacteria that are present in the tooth root. Pure distilled water was treated by plasma jet for one hour at flow rate 1 . Plasma water activated by plasma contains NO2, NO3, and H2O2 with a concentration (10,100,200) ppm, respectively. It was noted, as a result of direct exposure with the two values of gas flow rate and for different exposure times, an ideal killing rate (from 298 x 108 to zero)CFU/ml was obtained when the exposure time changed from (5-30) minutes with a constant gas flow rate of 2.5 ; while in the case of changing the gas flow rate from (0.5-2.5) and fixing time to 5 min, the killing rate decreased from (298 ×108 to 30×108) CFU/ml. In the case of (PAW) when the time changed (5-25) min, an ideal killing rate was obtained (298 x 108 to zero) CFU/ml; adopted one factor, where the results indicated that plasma-activated water is good in disinfecting the root canal of the tooth and inactivating bacteria.

Effect of plasma-activated water and buffer solution combined with ultrasound on fungicide degradation and quality of cherry tomato during storage

The purpose of this study was to examine plasma-activated buffer solution (PABS) and plasma-activated water (PAW) combined with ultrasonication (U) treatment on the reduction of chlorothalonil fungicide and the quality of tomato fruits during storage. To obtain PAW and PABS, an atmospheric air plasma jet was used to treat buffer solution and deionized water at different treatment times (5 and 10 min). For combined treatments, fruits were submerged in PAW and PABS, then sonicated for 15 min, and individual treatment without sonication. As per the results, the maximum chlorothalonil reduction of 89.29% was detected in PAW-U10, followed by 85.43% in PABS. At the end of the storage period, the maximum reduction of 97.25% was recorded in PAW-U10, followed by 93.14% in PABS-U10. PAW, PABS, and both combined with ultrasound did not significantly affect the overall tomato fruit quality in the storage period. Our results revealed that PAW combined with sonication had a significant impact on post-harvest agrochemical degradation and retention of tomato quality than PABS. Conclusively, the integrated hurdle technologies effectively reduce agrochemical residues, which helps to lower health hazards and foodborne illnesses.

The effect of plasma‐activated water in a mouse model of inflammatory bowel disease

AbstractInflammatory bowel disease (IBD) is a group of disorders with complex pathogenesis, including oxidative stress and microbial dysbiosis. The aim of this study was to analyze the effect of intracolonic administration of plasma‐activated water (PAW) on the oxidative status and gut microbiota diversity in the colon of healthy mice and mice with IBD. Interestingly, PAW increased oxidative stress markers in the colon tissue, and this effect was more pronounced in IBD mice. Our results show that PAW increases microbial diversity in a healthy gut and decreases it in an inflamed gut. We conclude that the effect of PAW is bidirectional and depends on the underlying condition. Our findings do not support the proposed therapeutic potential of PAW in IBD.

Physicochemical Properties of Plasma-Activated Water and Its Control Effects on the Quality of Strawberries

In this study, the effects of plasma-activated water (PAW), generated by dielectric barrier discharge cold plasma at the gas-liquid interface, on the quality of fresh strawberries during storage were investigated. The results showed that, with the prolongation of plasma treatment time, the pH of PAW declined dramatically and the electrical conductivity increased significantly. The active components, including NO2-, NO3-, H2O2, and O2-, accumulated gradually in PAW, whereas the concentration of O2- decreased gradually with the treatment time after 2 min. No significant changes were found in pH, firmness, color, total soluble solids, malondialdehyde, vitamin C, or antioxidant activity in the PAW-treated strawberries (p > 0.05). Furthermore, the PAW treatment delayed the quality deterioration of strawberries and extended their shelf life. Principal component analysis and hierarchical cluster analysis showed that the PAW 2 treatment group demonstrated the best prolonged freshness effect, with the highest firmness, total soluble solids, vitamin C, and DPPH radical scavenging activity, and the lowest malondialdehyde and ∆E* values, after 4 days of storage. It was concluded that PAW showed great potential for maintaining the quality of fresh fruits and extending their shelf life.

Effects of Plasma-Activated Water on Leaf and Fruit Biochemical Composition and Scion Growth in Apple.

The application of plasma-activated water (PAW) in agriculture has gained the attention of researchers and practitioners. In particular, treatment with PAW is a promising method for increasing scion and rootstock survival as well as augmenting the mineral nutrition applicable to tree fruit crops. However, the applications of PAW are hampered by the lack of information about the effects of PAW on apple tree condition and yield. The increase in survival rate by PAW is believed to stem from the general stimulation of physiological processes in the plant tissue. To assess the actual effect of the PAW treatments, one needs to consider an important indicator of young tree quality such as their vegetative growth. We conducted field experiments to study the possibility of use of PAW for increase in primary nutrient contents in fruits and leaves in an orchard, as well as to assess the scion survival rate and vegetative growth of young grafts in a nursery. The application of PAW influenced the fruitset, yield, leaf nitrogen (N) and potassium (K), fruit phosphorus (P), calcium (Ca) ascorbic acid (AA) and titratable acidity (TA). Treatment with PAW did not significantly reduce the negative impact of the rootstock thickness on the survival rate of bench grafts and their subsequent development. At the same time, scion survival tended to increase in the case when the scions and the rootstocks were of compatible thickness. Further studies of the PAW treatment effects are needed to better understand its applicability in diverse fields of horticulture.

Study of plasma activated water and secondary effects on water using gamma radiation with FTIR in seeds germinations

Plasma activated water (PAW) and gamma radiation have been arduously used in many horticultural implementations; especially in increasing plant germination rates and general growth advancements. Attention has to be paid to both the effect of PAW and gamma radiation. The detailed chemical composition and appearance of tap water and distilled water that has been stimulated by plasma and gamma radiation on seed germination using Fourier transform infrared spectroscopy (FTIR) technique and optical emission spectroscopy (OES) are to be analysed. The result found that one important property of air plasma treatment on water is the creation of reactive atom species such as oxygen (O), Nitrogen (N) also known as RONS, as well as other ion molecules radical to water. Whilst gamma radiation can directly induce and generate water molecules radicals by its strong electromagnetic fields.

ВОДА, АКТИВИРОВАННАЯ СВЧ-ПЛАЗМОЙ, КАК РЕГУЛЯТОР РОСТА ХВОЙНЫХ

The reduction of the world's forests threatens a global ecological catastrophe. The contribution of forests and phytoplankton of the seas and oceans in the processes of photosynthesis, responsible for maintaining oxygen in the Earth's atmosphere, is divided equally at a ratio of forest and water surface areas of 9:71. The protection and restoration of lost forests, in Russia coniferous forests, is a paramount task. The problem of forest restoration is being solved at the government level. Decree of the Government of the Russian Federation dated 21.09.2020 No. 1509 «On the peculiarities of the use, protection, protection, reproduction of forests ...». The effect of plasma-activated water (PAW) on the stimulation of seed germination, the development of conifers in the early stages of their growth was studied. PAW was obtained using UHF plasmotron generating plasma in the atmosphere. PAW contains solutions of hydrogen peroxide and nitrogen oxides, which are necessary for plant life. VAP solutions were tested by the concentration of hydrogen peroxide. The initial concentration of hydrogen peroxide was 8·10-3 M. The seeds of fir and larch were germinated on filters moistened with water in the control, in the experiment with VAP solutions. The most effective VAP solution was a solution with a hydrogen peroxide concentration of 2·10-6 M, which provided an increase in the germination of larch and fir seeds by 25 and 30%, respectively, compared with the control. The germinated seeds were placed in transparent culture vessels on sand, which was moistened once with water in the control, in the experiment with VAP solutions. The vessels were closed. Seedlings were grown in stressful isolation conditions. We tested the development remotely. By the 30th day, 5% of the seedlings survived in the control and 40-45% of the seedlings survived in the experiment.

Effect of plasma-activated water on microbial quality and physicochemical properties of fresh beef

Abstract This work studies the influence of plasma-activated water (PAW) on the decontamination of beef and its influence on the color, pH, the thiobarbituric acid reactive substance values (TBARS), and total volatile basic nitrogen (TVBN) values of meat. PAW was generated using non-thermal atmospheric pressure plasma jet (NTAPPJ). He + 0.2% N2 and He + 0.2% O2 were used as worker gas to generate PAW. The PAW produced by the He + O2 plasma system exhibited a higher potential for decontamination of beef than that produced by the He + N2 plasma system. The lightness value (L*) of treated beef does not exhibit a noticeable difference with the control one. TBARS values of all treated beef were lower than the rancidity threshold but significantly greater than that of control samples. The TVBN value of control beef samples reached the decay threshold after 18 days of stockpiling, but treated beef remained good. This work reveals that PAW can potentially inhibit the growth of microorganisms in beef.

Plasma-Activated Water for Food Safety and Quality: A Review of Recent Developments.

Plasma-activated water (PAW) has received a lot of attention lately because of its antibacterial efficacy and eco-friendly nature. Compared to traditional disinfectants, this novel and intriguing option has a high disinfectant capacity while causing little to no modifications to the foodstuffs. Until now, PAW has successfully demonstrated its effectiveness against a broad range of microorganisms on a wide variety of food items. Though the efficacy of PAW in microbial reduction has been extensively reviewed, a relatively significant issue of food quality has been largely overlooked. This review aims to summarize the current studies on the physicochemical characteristics and antimicrobial potential of PAW, with an in-depth focus on food quality and safety. According to recent studies, PAW can be a potential microbial disinfectant that extends the shelf life of various food products, such as meat and fish products, fruits and vegetables, cereal products, etc. However, the efficacy varies with treatment conditions and the food ingredients applied. There is a mixed opinion about the effect of PAW on food quality. Based on the available literature, it can be concluded that there has been no substantial change in the biochemical properties of most of the tested food products. However, some fruits and vegetables had a higher value for the enzyme superoxide dismutase (SOD) after PAW treatment, while only a few demonstrated a decrease in the Thiobarbituric acid reactive substances (TBARS) value. Sensory properties also showed no significant difference, with some exceptions in meat and fish products.

Antimicrobial effects of microwave plasma-activated water with skin protective effect for novel disinfectants in pandemic era

Skin antiseptics have important implications for public health and medicine. Although conventional antiseptics have considerable antimicrobial activity, skin toxicity and the development of resistance are common problems. Plasma-treated water has sterilization and tissue-regenerative effects. Therefore, the aim of this study was to identify whether plasma-activated water (PAW) manufactured by our microwave plasma system can be used as a novel antiseptic solution for skin protection. PAW was produced by dissolving reactive nitrogen oxide gas using microwave plasma in deionized water. The antibacterial effects of PAW against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Salmonella typhimurium and effective concentrations were investigated by a solid agar plate assay. The factors mediating the effects of PAW were evaluated by the addition of reactive species scavengers. Cytotoxicity and cell viability assays were performed to examine the protective effect of PAW on normal skin cells. PAW exhibited excellent sterilization and no toxicity in normal skin cells. Experiments also confirmed the potential of PAW as a sanitizer for SARS-CoV-2. Our findings support the use of PAW as an effective skin disinfectant with good safety in the current situation of a global pandemic.