It is shown that plasma‐activated water (PAW) improves tolerance against combined low temperature and hypoxia stresses during germination. Due to PAW's effect on the antioxidant system, PAW ...pretreatment mitigates the reducing effect on plant growth of the hydroponically applied NaCl. PAW pretreatment reduces the salt‐stress‐induced decrease of the cysteine and γ‐glutamylcysteine content and improves the plant's recovery after NaCl stress. PAW pretreatment also modifies the NaCl‐induced changes in carotenoid content, especially, β‐carotenes and xanthophylls. These compounds, together with glutathione can reduce salt‐induced damage through the removal of excess reactive oxygen species, which could be the basis of the protective effect of PAW.
It is shown that PAW improves tolerance against combined low temperature and hypoxia stresses during germination, and it mitigates the reducing effect of hydroponically applied NaCl on plant growth. PAW modifies the NaCl‐induced changes in the concentrations of thiols and carotenoids, which can reduce salt‐induced damage through the removal of the excess of reactive oxygen species
High power ultrasound (US) and cold gas-phase plasma (CP) are non-thermal processing technologies that maybe used in food processing industry. The main objective of this research was to study the ...effect of both treatments on selected yeasts (Rhodotorula spp. 74 and Candida spp. 86) in pure culture. Samples were treated by ultrasound with 57.50-, 86.25- or 115-μm amplitude, for 3, 6 or 9 min at 20 °C, and 40 or 60 °C in the case of thermosonication. For cold gas-phase plasma treatments, samples were treated at a gas flow of 0.75, 1 or 1.25 L min⁻¹, treatment time of 3, 4 or 5 min, and sample volume of 2, 3 or 4 mL. Each technology has its own advantages and is able to give the best effect on the desired target product. The experiment was designed using central composite design (CCD), and results were analysed and presented using response surface methodology (RSM). The greatest reduction of yeasts was observed after ultrasound treatments at 60 °C (thermosonication) and after plasma treatments, after the longest treatment time (5 min) and the lowest sample volume (2 mL). For high power ultrasound treatment, reduction in the number of yeast cells (N) can be attributed to elevated temperature (60 °C), cavitation and free radical formation. For plasma treatment, the inactivation can be attributed to UV radiation and plasma reactive oxygen species (ROS).
The aim of this work was to determine if PAW (Plasma Activated Water) seed treatment and growing conditions could have positive effects on lettuce seedlings and growth. The paper presents the results ...of a pot experiment on lettuce (Lactuca sativa L.) cultivation in greenhouse and field conditions after seed treatment with PAW. The experiment was conducted in two consecutive seasons in 2021 and 2022 and the following growth parameters were measured: head mass, rosette height, rosette width, number of leaves, root mass and root length. As a result of the study, it was found that lettuces grown in the greenhouse from PAW treated seeds had higher results in the first measurement for both cultivars (mass 32.26%, diameter 19.01%, number of leaves 13.49% and height 24.01%), while there were no statistically significant effects on the root system. The lowest results were obtained in untreated and field-grown plants. In addition, plant dry matter was measured and it was found that plants grown from PAW treated seeds had a higher percentage of dry matter (11.51% in 2021, and 11.58% in 2022). It was also found that cultivation in greenhouse resulted in a better quality of plants than the cultivation in the open field.
In this comparative study, the bacterial inactivation efficiency of plasma-activated water (PAW) generated by two distinct plasma reactors, one utilizing a nitrogen plasma jet electrode and the other ...a hybrid argon plasma reactor, was explored. The present study involved the assessment of antimicrobial activity against suspensions of three Gram-positive and three Gram-negative bacterial strains in their planktonic cell state. Bacterial suspensions were introduced into PAW five days after generation. Subsequently, the viability of the bacteria was assessed at various time intervals, specifically at 0.5, 1, 3, 5, 10, and 24 h, in order to evaluate the effect of inactivation. Structural changes in bacteria after PAW treatment were assessed using a scanning electron microscope (SEM). The physicochemical properties of PAW, including pH, conductivity, and concentrations of H2O2, NO2−, and NO3− during aging were measured. The present study demonstrated the effective inactivation of the tested bacterial strains by PAW. Gram-positive bacteria displayed greater resistance compared to Gram-negative species, with the lowest reductions in bacterial counts observed for B. cereus, and the highest for Escherichia coli O157:H7. Morphological damage was evident across all bacterial species examined. Physicochemical measurements showed slow decay of the reactive species in the aging process. This study illustrated the potential utility of PAW as an alternative disinfectant.
•Effects of low pressure DBD plasma on degradation of T-2 and HT-2 toxin was studied.•LC-MS/MS method was established for analyzing T-2 and HT-2 toxin.•Application of nitrogen as a working gas has a ...major effect on T-2/HT-2 degradation.
T-2 and its major metabolite HT-2 toxin are naturally occurring contaminants in cereals, with the highest concentrations determined in oats. Because of their toxicity and resistance to conventional methods used in mycotoxin degradation, development of new effective procedures for reduction of T-2/HT-2 toxin levels is needed. The aim of this study was to investigate the effect of different gas types within various timeframes on the efficiency of T-2 and HT-2 toxin degradation by low pressure dielectric barrier discharge (DBD) plasma in oat flour. Although humidity of the sample influences the intensity of the plasma, oxygen atoms efficiently oxidize the sample and produce CO and N2. Before and after treatment, T-2 and HT-2 toxin concentrations were analysed by the confirmatory liquid chromatography tandem-mass spectrometry (LC-MS/MS) method. The highest reduction of T-2 and HT-2 toxin of 43.25% and 38.54%, respectively, was achieved using nitrogen plasma and this proved to be time-dependent.
The work investigates the role of metals on the formation and stability of reactive oxygen and nitrogen species (RONS) in liquids treated with a surface‐wave microwave discharge. It is demonstrated ...that the high reduction potential metals can quasi‐neutralize the acidification induced by the plasma treatment, and thus reduce the rate of the NO
2
−
+
H
2
O
2
+
H
+
⟶ ${\text{NO}}_{2}^{-}+{{\rm{H}}}_{2}{{\rm{O}}}_{2}+{{\rm{H}}}^{+}\longrightarrow $ products reaction. As a consequence, while in the acidified plasma‐activated water the NO
2
− ${\text{NO}}_{2}^{-}$ production vanishes with increase in the treatment time, the addition of metals enhances the NO
2
− ${\text{NO}}_{2}^{-}$ production. The RONS concentrations are quasi‐stable for several weeks when pH is higher than 5.5, which can be achieved in a wide range of treatment conditions with the use of Mg powder, and at relatively shorter treatments with the usage of Zn.
It is demonstrated that the high reduction potential metals can quasi‐neutralize the acidification induced by the plasma treatment, and thus the production of NO
2
− ${\text{NO}}_{2}^{-}$ can be increased with the treatment time. Reactive oxygen and nitrogen species concentrations can be stabilized for several weeks at pH higher than 5.5, which can be achieved in a wide range of treatment conditions with the use of Mg powder, and at relatively shorter treatments with the usage of Zn.
The purpose of this research was to evaluate the effect of cold atmospheric pressure gas phase plasma treatment on anthocyanins and phenolic acids in sour cherry Marasca juice. Plasma treatment was ...optimized using a response surface methodology regarding the treatment time, sample volume and applied gas flow and compared to thermal pasteurization and untreated juice. Short treatment (3 min) of larger volume of the juice (3 mL) resulted in the highest concentration of both anthocyanins and phenolic acids. Compared to pasteurized and untreated juice, plasma treated sour cherry Marasca juice at optimized conditions had higher amount of phenolic compounds. Observed increase in phenolic compounds content in sour cherry Marasca juices could be a result of undefined small-sized aggregates or particles, which would be dissociated by the plasma treatment.
•The effect of plasma treatment on sour cherry Marasca juice phenolics was studied.•Treatment time, sample volume and applied gas flow were optimized.•Short plasma exposure and larger volume of juice gave the highest phenolic content.•Short plasma treatment increased anthocyanin and phenolic acid content.
To study the effect of atmospheric pressure plasma (APP) jet as a potential accelerator of the degradation of hydrogen peroxide in bleaching gels which could lead to better and faster bleaching.
25 ...pastilles of hydroxylapatite were colored in green tea for 8 hours and were randomly divided into five groups (n = 5). The bleaching process was performed with 30% and 40% hydrogen peroxide (HP) gel alone and in conjunction with helium APP jet. During the bleaching treatment, optical emission spectroscopy and non-contact surface temperature measurement using pyrometer were performed. Color of the pastilles was determined by a red-green-blue (RGB) colorimeter. PH values of bleaching gels were measured before and after the plasma treatment on additional 10 pastilles using a pH meter with contact pH electrode.
The color measurements of pastilles before and after the treatment showed that treatment with APP jet improved the bleaching effect by 32% and 15% in the case of 30% and 40% HP gel. Better results were obtained approximately six times faster than with a procedure suggested by the bleaching gel manufacturer. Optical emission spectroscopy proved that plasma has a chemically active role on the gel. After the APP treatment, pH values of bleaching gels dropped to about 50-75% of their initial value while the surface temperature increased by 8-10˚C above baseline.
The use of plasma jet provides more effective bleaching results in a shorter period of time without a significant temperature increase which may cause damage of the surrounding tissue.
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