Fungicidal efficiency of DBD cold plasma against Aspergillus niger on dried jujube

This study investigated the fungicidal efficiency and mechanism of action of dielectric barrier discharge cold atmosphere plasma (DBD-CAP) in inactivating Aspergillus niger (A. niger) spores. The disinfection efficacy and quality of dried jujube used as the processing application object were also studied. The results indicated that the Weibull + Tail model performed better for spore inactivation curves at different voltages among various treatment times, and the spore cells were reduced by 4.05 log (cfu/mL) in spores suspension at 70 kV after 15 min of treatment. This disinfection impact was further supported by scanning electron microscope (SEM) and transmission electron microscopy (TEM) images, which showed that the integrity of the cell membrane was damaged, and the intracellular content leaked out after DBD-CAP treatment. Elevated levels of reactive oxygen species (ROS) during the treatment increased the relative conductivity of cells, and leakage of nucleic acids and proteins further supported the disinfection impact. Additionally, the growth and toxicity of surviving A. niger spores after treatment were also greatly reduced. When DBD-CAP was applied to disinfecting dried jujube, the spore number exhibited a 2.67 log cfu/g reduction after treatment without significant damage observed onto the quality (P > 0.05).

Modification of soy protein isolate and pea protein isolate by high voltage dielectric barrier discharge (DBD) atmospheric cold plasma: Comparative study on structural, rheological and techno-functional characteristics

The modification in structural, rheological, and techno-functional characteristics of soy and pea protein isolates (SPI and PPI) due to dielectric barrier discharge cold plasma (DBD-CP) were assessed. The increased carbonyl groups in both samples with cold plasma (CP) treatment led to a reduction in free sulfhydryl groups. Moreover, protein solubility of treated proteins exhibited significant improvements, reaching up to 59.07 % and 41.4 % for SPI and PPI, respectively, at 30 kV for 8 min. Rheological analyses indicated that storage modulus (G') was greater than loss modulus (G″) for CP-treated protein gels. Furthermore, in vitro protein digestibility of SPI exhibited a remarkable improvement (4.78 %) at 30 kV for 6 min compared to PPI (3.23 %). Spectroscopic analyses, including circular dichroism and Fourier Transform-Raman, indicated partial breakdown and loss of α-helix structure in both samples, leading to the aggregation of proteins. Thus, DBD-CP induces reactive oxygen species-mediated oxidation, modifying the secondary and tertiary structures of samples.

Air and argon cold plasma effects on lipolytic enzymes inactivation, physicochemical properties and volatile profiles of lightly-milled rice

This study investigated the effectiveness of cold-plasma treatment using air and argon as input gas on deactivation of lipolytic enzymes in lightly-milled-rice (LMR). The results showed no significant inactivation in lipase and lipoxygenase using air-plasma. However, using argon as input gas, the residual activities of lipase and lipoxygenase were reduced to 64.51 % and 29.15 % of initial levels, respectively. Argon plasma treatment resulted in more substantial augmentation in peak and breakdown viscosities of LMR starch, suggesting an enhancement in palatability of cooked LMR with increased stickiness and decreased hardness. In contrast to the decrease in volatile compounds in LMR following argon plasma treatment, the concentrations of several prevalent aroma compounds, including 1-hexanol, 1-hexanal, and 2-pentylfuran, exhibited significant increments, reaching 1489.70 ng/g, 3312.10 ng/g, and 58.80 ng/g, respectively. These findings suggest the potential for enhancing various facets of the commercial qualities of LMR by utilizing different input gases during plasma treatment.

Cold plasma: A success road to mycotoxins mitigation and food value edition

Mycotoxins are common in many agricultural products and may harm both animals and humans. Dietary mycotoxins are reduced via physical, chemical, and thermal decontamination methods. Chemical residues are left behind after physical and chemical treatments that decrease food quality. Since mycotoxins are heat-resistant, heat treatments do not completely eradicate them. Cold plasma therapy increases food safety and shelf life. Cold plasma-generated chemical species may kill bacteria quickly at room temperature while leaving no chemical residues. This research explains how cold plasma combats mold and mycotoxins to guarantee food safety and quality. Fungal cells are damaged and killed by cold plasma species. Mycotoxins are also chemically broken down by the species, making the breakdown products safer. According to a preliminary cold plasma study, plasma may enhance food shelf life and quality. The antifungal and antimycotoxin properties of cold plasma benefit fresh produce, agricultural commodities, nuts, peppers, herbs, dried meat, and fish.

Cold-plasma activation converting conductive agent in spent Li-ion batteries to bifunctional oxygen reduction/evolution electrocatalyst for zinc-air batteries

Considerable amount of high-value transition metals components can be recycled in spent ternary lithium-ion batteries. In this study, we utilized the conductive agent carbon black, obtained from the leaching waste resulting from the chemical recovery of spent lithium-nickel-manganese-cobalt (NCM) oxide cathode materials. This process allows us to create valuable bifunctional catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER), facilitated by a facile cold plasma activation method, as a part of lithium batteries circular economy. The activated conductive agent (RCA-30) exhibited an ORR half-wave potential of 0.74 V (vs. RHE) in 0.1 mol/L KOH solution, and an OER overpotential of 360 mV at 10 mA cm-2 in 1 mol/L KOH electrolyte, owing to nitrogen doping of carbon black and activation of surface metal oxides. The complete zinc-air batteries incorporating the activated catalysts at the cathode exhibited an open circuit potential of up to 1.48 V and sustained cycling for 100 h at a current density of 5 mA cm-2. Additionally, the activated catalysts contributed to a power density of 92 mW cm-2 and a full discharge capacity of 640 mAh/g.

Cold plasma: Unveiling its impact on hydration, rheology, nutritional, and anti-nutritional properties in food materials - An overview

Non-thermal technologies, primarily employed for microbial inactivation and quality preservation in foods, have seen a surge in interest, with non-thermal plasma garnering particular attention. Cold plasma exhibits promising outcomes, including enhanced germination, improved functional and rheological properties, and microorganism destruction. This has sparked increased exploration across various domains, notably in hydration and rheological properties for creating new products. This review underscores the manifold benefits of applying cold plasma to diverse food materials, such as cereal and millet flours, and gums. Notable improvements encompass enhanced functionality, modified color parameters, altered rheological properties, and reduced anti-nutritional factors. The review delves into mechanisms like starch granule fragmentation, elucidating how these processes enhance the physical and structural properties of food materials. While promising for high-quality food development, overcoming challenges in scaling up production and addressing legal issues is essential for the technology's commercialization.

Combined of plasma-activated water and dielectric barrier discharge atmospheric cold plasma treatment improves the characteristic flavor of Asian sea bass (Lates calcarifer) through facilitating lipid oxidation

To explore the combination effects of plasma-activated water and dielectric barrier discharge (PAW-DBD) cold plasma treatment on the formation of volatile flavor and lipid oxidation in Asian sea bass (ASB), the volatile flavor compounds and lipid profiles were characterized by gas chromatography-ion mobility spectrometry and LC-MS-based lipidomics analyses. In total, 38 volatile flavor compound types were identified, and the PAW-DBD group showed the most kinds of volatile components with a significant (p < 0.05) higher content in aldehydes, ketones, and alcohols. A total of 1500 lipids was detected in lipidomics analysis, phosphatidylcholine was the most followed by triglyceride. The total saturated fatty acids content in PAW-DBD group increased by 105.02 μg/g, while the total content of unsaturated fatty acids decreased by 275.36 μg/g. It can be concluded that the PAW-DBD processing increased both the types and amounts of the volatile flavor in ASB and promoted lipid oxidation by altering lipid profiles.

Integrated in-package treatment of hydrogen peroxide and cold plasma for microbial inactivation of cabbage slices

The efficacy of an in-package microbial inactivation method, combining H2O2 and atmospheric dielectric barrier discharge cold plasma (ADCP) treatments (H2O2-ADCP), in reducing contamination of Brassica oleracea (cabbage) slices was investigated. Cabbage slices were placed in a polyethylene terephthalate container with a H2O2-soaked polypropylene pad attached to the inside of the lid, followed by subjecting the closed container to ADCP treatment. The H2O2-ADCP treatment inactivated Escherichia coli O157:H7 and Listeria monocytogenes, resulting in reductions of 1.8 and 2.0 log CFU/g, respectively, which were greater than the sum of the inactivation effects observed with each individual treatment. The combined treatment decreased the count of Bacillus cereus spores and indigenous bacteria by 1.0 log spores/g and 1.3 log CFU/g, respectively. Moreover, the in-package method did not alter the moisture content or texture of cabbage slices. These results demonstrate the potential of H2O2-ADCP as a microbial decontamination method for packaged cabbage slices.

Exploring Cold plasma technology: Enhancements in Carob seed germination, phytochemical Composition, and antioxidant activity

The cultivation of carob tree does not need many climatic and ecological requirements. The main limit to its large-scale cultivation is the defects for propagation with seeds. Addressing this, our study evaluated the effect of cold plasma pretreatment on carob seed germination. Impressively, cold plasma showcased beneficial effects by significantly increasing water uptake in seeds (CS: 1.71 ± 0.59; PS/3.99 ± 1.56) and decreasing the contact angle from 80.7° to 57.9°, enhancing the seed surface's hydrophilicity. While the germination rate enhancement was subtle, the treatment presented an innovative route to modifying the seed's physiochemical properties. Specifically, storage proteins like albumin, globulin, and prolamin were notably reduced (Albumin (from 7.67 to 4.95 mg/g DW), Globulin (from 8.52 to 5.80 mg/g DW) and Prolamin (from 3.53 to 1.66 mg/g DW)). Additionally, there was a decline in the overall content of polyphenols (from 846.88 to 760.94 mg GAE/100g DW) and flavonoids (from 790.93 to 502.95 mg GAE/100g DW) and a decrease in the ferric reducing power (from 34.48 to 26.39 mg AAE/g DW). However, radical scavenging activity remained consistent. Intriguingly, FTIR-ATR spectral analysis post plasma treatment indicated oxidative alterations in the seed coat, marked by a distinctive intensity at 1732 cm⁻1. This investigation suggests that the application of eco-friendly technology could provide improvements in seed surface's hydrophilicity, but appropriate conditions could be chosen to increase germination efficiency.

From field to table: Ensuring food safety by reducing pesticide residues in food

The present review addresses the significance of lowering pesticide residue levels in food items because of their harmful impacts on human health, wildlife populations, and the environment. It draws attention to the possible health risks-acute and chronic poisoning, cancer, unfavorable effects on reproduction, and harm to the brain or immunological systems-that come with pesticide exposure. Numerous traditional and cutting-edge methods, such as washing, blanching, peeling, thermal treatments, alkaline electrolyzed water washing, cold plasma, ultrasonic cleaning, ozone treatment, and enzymatic treatment, have been proposed to reduce pesticide residues in food products. It highlights the necessity of a paradigm change in crop protection and agri-food production on a global scale. It offers opportunities to guarantee food safety through the mitigation of pesticide residues in food. The review concludes that the first step in reducing worries about the negative effects of pesticides is to implement regulatory measures to regulate their use. In order to lower the exposure to dietary pesticides, the present review also emphasizes the significance of precision agricultural practices and integrated pest management techniques. The advanced approaches covered in this review present viable options along with traditional methods and possess the potential to lower pesticide residues in food items without sacrificing quality. It can be concluded from the present review that a paradigm shift towards sustainable agriculture and food production is essential to minimize pesticide residues in food, safeguarding human health, wildlife populations, and the environment. Furthermore, there is a need to refine the conventional methods of pesticide removal from food items along with the development of modern techniques.

Understanding the atmospheric cold plasma-induced modification of finger millet (Eleusine coracana) starch and its related mechanisms

This research was conducted to evaluate the effects of cold plasma (CP) on finger millet starch (FMS). FMS was exposed to partially ionized gas at varying voltages (170, 200, and 230Volt) for varied time (10, 20, and 30mins). The impact of treatment was studied using physico-chemical, and functional properties, and the mechanisms of starch modification occurring were stated. A significant reduction in the degree of polymerization was noticed based on parameters like reducing sugar, amylose content, solubility, and molecular weight. However, in certain voltage and time combinations, crosslinking was also confirmed by analysis such as XRD, FTIR, DSC, etc. The properties of starch were altered such as remarkable increase in water solubility by 6.7 times for highest voltage and longest time (230 V/30 min) was registered. NMR data suggested valuable findings- oxidation of OH group at C6 position of starch led to formation of carbonyl group followed by carboxyl group. NMR also showed a decrease in OH protons confirming crosslinking and hence all these analyses helped to conclude findings about the quality changes using CP. It was observed that the highest voltage and considerably longer exposure time of 20 and 30 min induced significant changes in the FMS.

Effects of cold plasma pretreatment combined with sodium periodate on property enhancement of dialdehyde starch prepared using native maize starch

This study represents the inaugural investigation into the effect of cold plasma (CP) pretreatment combined with sodium periodate on the preparation of dialdehyde starch (DAS) from native maize starch and its consequent effects on the properties of DAS. The findings indicate that the maize starch underwent etching by the plasma, leading to an increase in the particle size of the starch, which in turn weakened the rigid structure of the starch and reduced its crystallinity. Concurrently, the plasma treatment induced cleavage of the starch molecular chain, resulting in a decrease in the viscosity of the starch and an enhancement of its fluidity. These alterations facilitated an increased contact area between the starch and the oxidising agent sodium periodate, thereby augmenting the efficiency of the DAS preparation reaction. Consequently, the aldehyde group content was elevated by 9.98 % compared to the conventional DAS preparation methodology. Therefore, CP could be an efficient and environmentally friendly non-thermal processing method to assist starch oxidation for DAS preparation and property enhancement.

Effect of (multi pin) atmospheric cold plasma treatment on curcumin extraction and investigating phytochemicals, antioxidants, physical and morphological properties of turmeric (Curcuma longa L.) powder

This investigation was focused on the impact of cold plasma (CP) on the extraction of curcumin and bioactive compounds of turmeric powder (TP). TP was treated with CP at different applied voltages (10, 20, and 30 kV), with various exposure times (10, 20, and 30 min). The curcumin content was highest at 30 kV for 10 min with a yield of 46.49 mg/g of TP. Total phenols significantly (p < 0.05) enhanced from 163.91 to 360.78 mg GAE/g DW accompanied by a remarkable 16% increment in total flavonoids, paralleled by a 26% increment in antioxidants as of control. Nuclear magnetic resonance spectra justified the extraction of curcuminoids. Moreover, micrographs displayed cell lysis in the treated powder. CP has exhibited a positive effect on surface colour parameters and thermal properties of TP. Overall, CP technology can be tailored for better curcumin extraction and the enhancement of phytochemicals.

Efficient degradation of imidacloprid by surface discharge cold plasma: Mechanism of interaction between ROS and molecular structure and evaluation of residual toxicity

Incorrect use of neonicotinoid pesticides poses a serious threat to human and pollinator health, as these substances are commonly present in bee products and even drinking water. To combat this threat, the study developed a new method of degrading the pesticide imidacloprid using surface discharge cold plasma oxidation technology. The study showed that this method achieved a very high efficiency of imidacloprid degradation of 91.4%. The main reactive oxygen species (H2O2, O3, ·OH, O2-, 1O2) effectively participated in the decomposition reaction of imidacloprid. Reactive oxygen species were more sensitive to the structure of the nitroimine group. Density functional theory (DFT) further explored the sites of reactive oxygen species attack on imidacloprid and revealed the process of energy change of attacking imidacloprid. In addition, a degradation pathway for imidacloprid was proposed, mainly involving reactive oxygen species chemisorption, a ring-opening intermediate, and complete cleavage of the nitroimine group structure. Model predictions indicated that acute oral and developmental toxicity were significantly reduced after cold plasma treatment, as confirmed by insect experiments. Animal experiments have shown that plasma treatment reduces imidacloprid damage to mice hippocampal tissue structure and inhibits the reduction of brain-derived neurotrophic factor content, thus revealing the detoxification mechanism of the body.

Inactivation mechanism of cold plasma combined with 222 nm ultraviolet for spike protein and its application in disinfecting of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible virus that has precipitated a worldwide pandemic of coronavirus disease since 2019. Developing an effective disinfection strategy is crucial to prevent the risk of surface cross-contamination by SARS-CoV-2. This study employed pseudovirus and the receptor-binding domain (RBD) protein of SARS-CoV-2 as models to investigate the spike protein inactivation process and its underlying mechanisms using a novel nonthermal technology. Cold plasma combined with 222 nm ultraviolet (CP+UV) treatment was applied to accelerate the generation of reactive species and enhance sterilization efficiency. The results indicated that the binding activity of RBD protein was completely inhibited at specific concentrations (0.01-0.05 mg/cm2) with corresponding treatment times of 15-30 s. The mechanism potentially involves the reactive species generated by CP+UV, which react with the spike protein RBD of SARS-CoV-2, leading to the loss of SARS-CoV-2 infectivity by causing damage to the β-sheet structure and chemical bonds in the RBD protein. Validated by a biosafety level 3 (BSL3) laboratory, the CP+UV treatment for 30 s could completely inactivate SARS-CoV-2 with a concentration of 19054 ± 1112 TCID50/cm2. Therefore, this study potentially provides a novel disinfection strategy for the inactivation of SARS-CoV-2 on surface cross-contamination.

Multi-scale structural disruption induced by radio frequency air cold plasma accelerates enzymatic hydrolysis/ hydroxypropylation of tapioca starch

This study investigated the effects of radio frequency air cold plasma (RFACP) pretreatment on the multi-scale structures, physicochemical properties, enzymatic hydrolysis, and hydroxypropylation of tapioca starch. The results showed that cold plasma (CP) made starch granules rough on the surface and disrupted long- and short-range ordered structures, reducing relative crystallinity from 43.8 % to 37.4 % and R1047/1022 value from 0.992 to 0.934. Meanwhile, the starch molecules were depolymerized and oxidized by CP, reducing weight-average molecular weight from 9.64 × 107 to 2.17 × 107 g/mol, while increasing carbonyl and carboxyl groups by up to 118 % and 53 %. Additionally, CP-treated starches exhibited higher solubility and swelling power, along with lower gelatinization enthalpy. Short-time CP pretreatment (10 min) promoted the hydroxypropylation of starch and increased the molar substitution (0.081-0.112). Also, CP pretreatment accelerated enzymatic hydrolysis of starch, as indicated by the increase in hydrolysis rate (1.846 × 10-3-2.033 × 10-3 min-1) and degree of hydrolysis (51.45 % - 59.92 %). Overall, the multi-scale structural disruption induced by CP treatment facilitated the accessibility of enzymes/chemical reagents into starch granules and glucan chains. This study suggested that RFACP could be used for starch pretreatment to increase production efficiency in modified starch production, as well as in brewing and fermentation industries.

Plasma-activated liquid as a potential decontaminant in healthcare: assessment of antibacterial activity and use with cleaning cloths

BACKGROUND

Cold air plasma (CAP) can generate plasma-activated liquids (PALs) with high concentrations of reactive oxygen (ROS) and nitrogen species (RNS), e.g., nitrites, with antimicrobial properties.

AIM

We investigated the concentrations of ROS and RNS in saline PAL. We assessed planktonic bacterial inactivation by PAL and the decontamination of contaminated cleaning cloths.

METHODS

Phosphate-buffered saline (PBS) was treated with an air-driven CAP jet for 90 or 300 s to generate PAL. The ROS and RNS were measured using quantitative fluorescent (2,7-dichlorofluorescin diacetate) and colourimetric (Greiss) assays. Isolates of MRSA and Escherichia coli were incubated in PAL overnight and inactivation measured through colony forming unit (cfu) assays. Sections of cleaning cloths were incubated with MRSA and E. coli, and treated with PAL for 1 h. Bacterial inactivation was measured through resazurin reduction assays.

RESULTS

Nitrites increased from 0.1 μM in untreated PBS to 49.1 μM and to 94.0 μM in 90- and 300-s CAP-treated PAL, respectively. ROS increased from 30 μM in untreated PBS to 75 μM and to 103 μM in 90- and 300-s CAP-treated PAL, respectively. 90-s PAL reduced MRSA and E. coli viability (P<0.05) and 300-s PAL resulted in more than a 7-log reduction of both. One-hour treatment of contaminated cleaning cloths in PAL resulted in a 55% and 73% reduction in viable MRSA and E. coli, respectively (P<0.05).

CONCLUSION

Inactivation of planktonic bacteria correlated with ROS and RNS concentrations. PAL reduced bacteria contaminated cleaning cloths. PAL has potential as a hospital disinfectant, including cleaning cloths.

Radical species generating technologies for decontamination of Listeria species in food: a recent review report

Foodborne illnesses occur due to the contamination of fresh, frozen, or processed food products by some pathogens. Among several pathogens responsible for the illnesses, Listeria monocytogenes is one of the lethal bacteria that endangers public health. Several preexisting and novel technologies, especially non-thermal technologies are being studied for their antimicrobial effects, particularly toward L. monocytogenes. Some noteworthy emerging technologies include ultraviolet (UV) or light-emitting diode (LED), pulsed light, cold plasma, and ozonation. These technologies are gaining popularity since no heat is employed and undesirable deterioration of food quality, especially texture, and taste is devoided. This review aims to summarize the most recent advances in non-thermal processing technologies and their effect on inactivating L. monocytogenes in food products and on sanitizing packaging materials. These technologies use varying mechanisms, such as photoinactivation, photosensitization, disruption of bacterial membrane and cytoplasm, etc. This review can help food processing industries select the appropriate processing techniques for optimal benefits, in which the structural integrity of food can be preserved while simultaneously destroying L. monocytogenes present in foods. To eliminate Listeria spp., different technologies possess varying mechanisms such as rupturing the cell wall, formation of pyrimidine dimers in the DNA through photochemical effect, excitation of endogenous porphyrins by photosensitizers, generating reactive species, causing leakage of cellular contents and oxidizing proteins and lipids. These technologies provide an alternative to heat-based sterilization technologies and further development is still required to minimize the drawbacks associated with some technologies.

From feed to functionality: Unravelling the nutritional composition and techno-functional properties of insect-based ingredients

In recent years, there has been a growing interest in using insects as a sustainable resource for biorefinery processes. This emerging field aims to convert insect biomass into valuable products while minimizing waste. The integration of emerging green technologies and the efficient extraction of high-value compounds from insects offer promising avenues for addressing the growing demand for sustainable food production and resource utilization. The review examines the impact of dietary modifications on the nutritional profile of insects. It highlights the potential for manipulating insect feed to optimize protein quality, amino acid profile, lipid content and fatty acid composition. Additionally, innovative green processing technologies such as ultrasound, high pressure processing, pulsed electric fields, cold plasma and enzymatic hydrolysis are discussed for their ability to enhance the extraction and techno-functional properties of insect-based ingredients. The review finds that dietary modifications can impact the nutritional composition of insects, allowing the customization of their nutrient content. By optimizing the insect feed, it is possible to increase the quantity and improve the quality of essential nutrients like proteins or lipids in the derived ingredients. Moreover, alternative processing technologies can improve the techno-functional properties (e.g., solubility, water and oil holding capacities, among others) of insect-based ingredients by modifying proteins' conformation. By harnessing these strategies, researchers and industry professionals can unlock the full potential of insects as a sustainable and nutritional food source, paving the way for innovative insect-based food products.

The amelioration of salt stress-induced damage in fenugreek through the application of cold plasma and melatonin

Nowadays, it is increasingly crucial to combine innovative approaches with established methods to enhance plant tolerance and maximize the production of beneficial compounds. With this aim in view, a study was carried out to investigate how different melatonin concentrations (0, 30, and 60 ppm), cold plasma treatment (at 3000 and 4000 V), and varying exposure durations (0, 1, 2, and 4 min) affect the physiological and biochemical attributes of fenugreek plants, as well as the levels of diosgenin under salinity stress. This study revealed that the application of 3000 V cold plasma for 2 min with 60 ppm melatonin by establishing cellular redox homeostasis in salinity-treated fenugreek plants, effectively prevented the destruction of pigments and reduced the electrolyte leakage index of malondialdehyde content. The utilization of these two elicitors has the potential to trigger multiple pathways, including the enzymatic and non-enzymatic antioxidants biosynthesis, and abscisic acid-dependent pathways. This activation results in an enhanced production of abscisic acid, auxin, and endogenous melatonin, along with the regulation of signal transduction pathways. Surprisingly, applying these two treatments increased the expression of SQS, CAS, SSR, BGL, SEP, SMT, and diosgenin content by 13, 22.5, 21.6, 19, 15.4, 12, and 6 times respectively. The findings highlight the intricate interplay between these treatments and the positive impact of their combined application, opening up avenues for further research and practical applications in improving plant tolerance to environmental stresses.

Cold atmospheric pressure air plasma jet disinfection of table eggs: Inactivation of Salmonella enterica, cuticle integrity and egg quality

Eggshell cuticles are first lines of defense against egg-associated pathogens, such as Salmonella enterica serovar Enteritidis (SE). Infections from eggs contaminated with this strain remain a significant risk. In addition, changes in the cuticle are closely related to changes in egg safety. The emerging non-thermal atmospheric pressure plasma technology enables a high rate of microbial inactivation at near-ambient temperatures, making it ideal for food safety applications. This study examines the effects of a cold atmospheric pressure air plasma jet (CAAP-J) on eggshell cuticle and egg quality whilst inactivating SE. Shell eggs inoculated with SE (7 log10 cfu/egg) were used as the samples to test the decontamination performance of the device. The tests were conducted using an industrial CAAP-J with different power levels (600-800 W), exposure times (60-120 s), at a fixeddistance of 20 mm from the plasma jet and an air flow rate of 3600 L/h. It was found that the best results were obtained after 120 s at maximum plasma power (800 W). Subsequent to the implementation of this plasma procedure, it was determined that no viable cells could be detected. After CAAP-J treatment, the temperature remains below 50.5 °C, thereby minimizing the risk of altering egg quality. All specific measurements (egg white pH, yolk pH, yolk color, HU, and eggshell breaking strength) have shown that CAAP-J treatment has no negative effect on egg quality. No changes in eggshell cuticle quality after CAAP-J treatment was confirmed through scanning electron microscope (SEM).

In vivo biological analysis of cold plasma on allergenicity reduction of tropomyosin in shrimp

In vivo biological regulations of the allergenicity of tropomyosin (TM) treated by cold plasma (CP) were investigated by in vivo mouse model. The sensitization models of Balb/c mice were successfully established. CP treatment reduced the allergic symptoms of mice and regulated the Th1/Th2 balance to prevent allergy by activating Treg cells, which was deduced by serum and cytokines analysis. For intestinal flora analysis, allergy occurrence was accompanied by the decreased species abundance and the increased species diversity of intestinal flora. The significant species composition difference between the TM group and the PBS group showed a possible connection between bacterial diversity and allergy. Furthermore, Firmicutes, Bacteroidetes, Parabacteroides, Alloprevotella, Bacteroides, and Lachnospiraceae could relate to allergy occurrence. Intestinal section analysis suggested that allergy occurrence was accompanied by the damaged intestinal structure, and CP treatment could relieve the damage caused by an allergy.

Application of cold argon plasma on germination, root length, and decontamination of soybean cultivars

Applying cold discharge plasma can potentially alter plants' germination characteristics by triggering their physiological activities. As a main crop in many countries, soybean was examined in the present study using cultivars such as Arian, Katoul, Saba, Sari, and Williams in a cold argon plasma. This study has been motivated by the importance of plant production worldwide, considering climate change and the increasing needs of human populations for food. This study was performed to inspect the effect of cold plasma treatment on seed germination and the impact of argon plasma on microbial decontamination was investigated on soybeans. Also, the employed cultivars have not been studied until now the radicals generated from argon were detected by optical emission spectrometry (OES), and a collisional radiative model was used to describe electron density. The germination properties, including final germination percentage (FGP), mean germination time (MGT), root length, and electrical conductivity of biomolecules released from the seeds, were investigated after the plasma treatments for 30, 60, 180, 300, and 420 s. The decontamination effect of the plasma on Aspergillus flavus (A.flavus) and Fusarium solani (F.solani) was also examined. The plasma for 60 s induced a maximum FGP change of 23.12 ± 0.34% and a lowest MGT value of 1.40 ± 0.007 days. Moreover, the ultimate root length was 56.12 ± 2.89%, in the seeds treated for 60 s. The plasma exposure, however, failed to yield a significant enhancement in electrical conductivity, even when the discharge duration was extended to 180 s or longer. Therefore, the plasma duration of 180 s was selected for the blotter technique. Both fungi showed successful sterilization; their infectivity inhibition was 67 ± 4 and 65 ± 3.1%, respectively. In general, the cold plasma used for soybeans in the present study preserved their healthy qualities and reduced the degree of fungal contamination.

The FEDBD plasma's quantitative investigation of skin parameters: Skin elasticity, thickness, density, tissue oxygenation, perfusion, and edema

This study used the FEDBD plasma device for skin rejuvenation in animal samples. There were two groups of six male Wistar rats. Before starting the treatment, immediately after the treatment, the fourth week, and the tenth week of follow-up, biometric tests were performed, including moisture level, evaporation from the skin surface, erythema and melanin, skin elasticity and firmness with an MPA9 device and cutometer. The thickness and density of the epidermis and dermis, an essential indicator in rejuvenation, were evaluated with a skin ultrasound device. Also, the level of oxygen, perfusion, and interstitial water (edema) was checked using a Tivita tissue hyperspectral camera at a depth of 6 mm of the skin.

Intervention mechanisms of cold plasma pretreatment on the quality, antioxidants and reactive oxygen metabolism of fresh wolfberries during storage

Fresh wolfberries, a nutritious "super fruit", face limited marketing potential due to storage difficulties. This study aimed to enhance their storage stability using dielectric barrier discharge plasma (DBD) pretreatment and investigate the intervention mechanism. The results indicated that the optimal condition of DBD pretreatment for fresh wolfberries was 13.64 kV, 70 s and 2.7 kHz, which extended their shelf from 2 to 5 d at room temperature. This pretreatment reduced decay, weight loss, and firmness reduction by inactivating microorganisms and inhibiting respiration. Additionally, the decline of phenols, flavonoids, ascorbic acid, and antioxidant activity was inhibited, while maintaining high content of polysaccharides, titratable acid, and carotenoids. Interestingly, moderate DBD treatment produced reactive oxygen species (ROS) that triggered the defense response of wolfberries' ROS metabolism system and promoted the biosynthesis of flavonoids, thereby enhancing resistance to decay. The findings offer new insight into plasma effects on fruits and vegetables.

The interaction of plasma distance and exposure time

This study aimed to analyse the efficacy of a new cold plasma device adapted for treatment with a low power consumption . We tested the reduction of bacterial cells in biofilms of E. coli, S. aureus and P. aeruginosa. . The results show significant differences between bacterial cells, suggesting that Gramme-positive S. aureus is less susceptible to plasma treatment than Gramme-negative E. coli and P. aeruginosa. Increasing the exposure time and decreasing the distance decreases the number of cells in the biofilm. However, the combination of close distance and long exposure time resulted in synergistic effects. We demonstrated a reduction of up to 6.6 log CFU cm2 for E. coli at 1 mm and an exposure time of 60 seconds. All these indicate that the new cold plasma jet device can be an important key to ensuring hygiene and numerous applications in medicine and engineering are possible.

A non-thermal modification method to promote the interaction of zein-alginate oligosaccharides composites for better encapsulation and stability-Cold plasma

This current research explored the application of cold plasma (CP) treatment to modify zein-alginate oligosaccharide (zein-AOS) composites in an ethanol-water solution. Anti-solvent method was used to prepare zein-AOS nanoparticles (NPs), and the objective was to investigate the mechanism by which CP promotes interaction between protein and saccharides. Characterization results indicated that CP treatment improved hydrogen bonding and electrostatic interaction between zein and AOS. The CP zein-AOS NPs underwent dispersion and rearrangement, resulting in smaller aggregates with better dispersibility. Among the various induction conditions tested, the zein-AOS85 NPs (induced at 85 W for 2 min) exhibited superior performance as delivery wall materials, with smaller particle size (234.67 nm), larger specific surface area (9.443 m2/g), and higher surface charge (-35.43 mV). In addition, zein-AOS85 showed high stability when used as delivery wall material, providing more binding sites and self-assembly dynamics for nutrients. Curcumin was used as the nutrient model in this study, and CP was found to enhance hydrogen bonding, electrostatic interaction, and hydrophobic interaction between zein, AOS, and nutrients, resulting in increased encapsulation efficiency (EE) from 63.80 % to 85.17 %. The delivery system also exhibited good pH, ionic strength, storage, and dispersion stability.

Changes in the structure and hydration properties of high-temperature peanut protein induced by cold plasma oxidation

To improve the hydration properties of high-temperature pressed peanut protein isolate (HPPI), we investigated the effect of cold plasma (CP) oxidation on functional and structural properties. Compared to HPPI, the hydrated molecules number and the surface contact angle were significantly decreased at 70 W, from 77.2 × 109 to 17.7 × 109 and from 85.74° to 57.81°, respectively. The reduction of the sulfhydryl content and the increase of the disulfide bond and di-tyrosine content indicated that the structural transformation was affected by the oxidation effect. In terms of structural changes, a stretched tertiary structure, ordered secondary structure, and rough apparent structure were observed after CP treatment. Additionally, the enhancement of surface free energy and group content such as -COOH, -CO and -OH on the surface of HPPI contributed to the formation of hydrated crystal structures. In general, the oxidation effect of CP effectively improved the hydration properties of HPPI and broaden its application field.

Cold atmospheric pressure plasma-antibiotic synergy in Pseudomonas aeruginosa biofilms is mediated via oxidative stress response

Cold atmospheric-pressure plasma (CAP) has emerged as a potential alternative or adjuvant to conventional antibiotics for the treatment of bacterial infections, including those caused by antibiotic-resistant pathogens. The potential of sub-lethal CAP exposures to synergise conventional antimicrobials for the eradication of Pseudomonas aeruginosa biofilms is investigated in this study. The efficacy of antimicrobials following or in the absence of sub-lethal CAP pre-treatment in P. aeruginosa biofilms was assessed. CAP pre-treatment resulted in an increase in both planktonic and biofilm antimicrobial sensitivity for all three strains tested (PAO1, PA14, and PA10548), with both minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs) of individual antimicrobials, being significantly reduced following CAP pre-treatment of the biofilm (512-fold reduction with ciprofloxacin/gentamicin; and a 256-fold reduction with tobramycin). At all concentrations of antimicrobial used, the combination of sub-lethal CAP exposure and antimicrobials was effective at increasing time-to-peak metabolism, as measured by isothermal microcalorimetry, again indicating enhanced susceptibility. CAP is known to damage bacterial cell membranes and DNA by causing oxidative stress through the in situ generation of reactive oxygen and nitrogen species (RONS). While the exact mechanism is not clear, oxidative stress on outer membrane proteins is thought to damage/perturb cell membranes, confirmed by ATP and LDH leakage, allowing antimicrobials to penetrate the bacterial cell more effectively, thus increasing bacterial susceptibility. Transcriptomic analysis, reveals that cold-plasma mediated oxidative stress caused upregulation of P. aeruginosa superoxide dismutase, cbb3 oxidases, catalases, and peroxidases, and upregulation in denitrification genes, suggesting that P. aeruginosa uses these enzymes to degrade RONS and mitigate the effects of cold plasma mediated oxidative stress. CAP treatment also led to an increased production of the signalling molecule ppGpp in P. aeruginosa, indicative of a stringent response being established. Although we did not directly measure persister cell formation, this stringent response may potentially be associated with the formation of persister cells in biofilm cultures. The production of ppGpp and polyphosphate may be associated with protein synthesis inhibition and increase efflux pump activity, factors which can result in antimicrobial tolerance. The transcriptomic analysis also showed that by 6 h post-treatment, there was downregulation in ribosome modulation factor, which is involved in the formation of persister cells, suggesting that the cells had begun to resuscitate/recover. In addition, CAP treatment at 4 h post-exposure caused downregulation of the virulence factors pyoverdine and pyocyanin; by 6 h post-exposure, virulence factor production was increasing. Transcriptomic analysis provides valuable insights into the mechanisms by which P. aeruginosa biofilms exhibits enhanced susceptibility to antimicrobials. Overall, these findings suggest, for the first time, that short CAP sub-lethal pre-treatment can be an effective strategy for enhancing the susceptibility of P. aeruginosa biofilms to antimicrobials and provides important mechanistic insights into cold plasma-antimicrobial synergy. Transcriptomic analysis of the response to, and recovery from, sub-lethal cold plasma exposures in P. aeruginosa biofilms improves our current understanding of cold plasma biofilm interactions.

Cold plasma within a stable supercavitation bubble - A breakthrough technology for efficient inactivation of viruses in water

Water scarcity, one of the most pressing challenges we face today, has developed for many reasons, including the increasing number of waterborne pollutants that affect the safety of the water environment. Waterborne human, animal and plant viruses represent huge health, environmental, and financial burden and thus it is important to efficiently inactivate them. Therefore, the main objective of this study was to construct a unique device combining plasma with supercavitation and to evaluate its efficiency for water decontamination with the emphasis on inactivation of viruses. High inactivation (>5 log10 PFU/mL) of bacteriophage MS2, a human enteric virus surrogate, was achieved after treatment of 0.43 L of recirculating water for up to 4 min. The key factors in the inactivation were short-lived reactive plasma species that damaged viral RNA. Water treated with plasma for a short time required for successful virus inactivation did not cause cytotoxic effects in the in vitro HepG2 cell model system or adverse effects on potato plant physiology. Therefore, the combined plasma-supercavitation device represents an environmentally-friendly technology that could provide contamination-free and safe water.

Response surface methodology (RSM) for optimizing ozone-assisted process parameters for formaldehyde removal

Formaldehyde, a volatile organic compound (VOC), is one of the main gaseous pollutants from commercial cooking. The present study evaluated the effectiveness of a laboratory-scale ozone-assisted indirect plasma method for formaldehyde removal using response surface methodology (RSM). A dielectric barrier discharge (DBD) reactor was used for ozone generation. Inlet HCHO concentration, ozone concentration, and residence time were considered the design parameters, and formaldehyde removal efficiency (response 1) and energy yield (response 2) were considered response parameters. The optimized models showed a positive correlation between the predicted and experimental outcomes. Inlet ozone concentration, the most significant parameter in the removal efficiency model, represented a positive correlation with this response in most parts of the operating region. The optimal point with the highest desirability (i.e., D1 point) was obtained at the inlet HCHO concentration of 120 ppm, inlet ozone concentration of 40 ppm, and reaction time of 11.35 s within the parameter ranges studied, resulting in 64% removal efficiency and 2.64 g/kWh energy yield. At the point with the second highest desirability (D2), 100% removal efficiency along with 0.7 g/kWh energy yield was achieved indicating the very good performance of the process. The indirect plasma approach used in this study presented a successful performance in terms of removal efficiency along with acceptable energy yield compared to other plasma-assisted processes reported in the literature. The results suggested that ozone-assisted indirect plasma treatment can be utilized as an efficient alternative method for formaldehyde removal in commercial kitchens, while efficiency or energy yield should be prioritized for optimizing operating conditions.

Non-thermal technologies for the conservation of açai pulp and derived products: A comprehensive review

Açai (Euterpe oleracea) is one of the main sustainable extractive crops in the Amazon region, widely consumed by the local population and a significant export product. This review presents the current knowledge regarding nonthermal technologies employed in açai processing. This review aims to discuss and compare the main results attained by the application of HPP, ultrasound, ozone, UV light, cold plasma, and pulsed electric field on microbial inactivation, enzymatic inhibition, and the content of anthocyanin and other bioactive compounds after açai pulp processing. The discussion compares these technologies with pasteurization, the current main technology applied to açai sanitization. This review shows that there are still many gaps to be filled concerning açai processing in thermal and non-thermal technologies. Data analysis allowed the conclusion that pasteurization and HPP are, up to now, the only technologies that enable a 5-log CFU reduction of yeasts, molds, and some bacteria in açai. However, no study has reported the inactivation of Trypanosoma cruzi, which is the major gap found in current knowledge. Other technologies, such as pulsed electric field, cold plasma, and ultrasound, require further development and process intensification studies to be as successful as HPP and pasteurization.

Influence of ozone supply mode and aeration on photocatalytic ozonation of organic pollutants in wastewater using TiO2 and ZnO nanoparticles

Photocatalytic ozonation, which combines the effects of lighting and ozonation, has been shown to enhance the decolorization and degradation of organic pollutants in wastewater. Dye solutions with concentrations of 10 ppm for both methylene blue and methyl orange dyes were used. The influence of ozoneation on the performance of photocatalytic activity of TiO2 and ZnO nanoparticles for the removal of organic dyes from aqueous solutions was investigated. To evaluate their efficacy for the removal of methylene blue and methyl orange dyes from aqueous solutions, the photocatalysts were exposed to UV light for 90 min, with ozone supplied either intermittently or continuously by an SDBD cold plasma reactor. The photocatalysts utilized in this study were characterized using SEM and XRD techniques. The degree of color degradation was determined using UV-Vis spectroscopy. The results demonstrate that TiO2 and ZnO nanoparticles exhibit different degrees of photocatalytic activity for the two dyes. The addition of ozone was found to enhance both the color degradation and mineralization rates of the pollutants, with intermittent ozonation proving more effective than continuous ozonation. The most significant color degradation results were obtained using TiO2 nanoparticles with intermittent ozonation for methylene blue dye (97 %) and ZnO nanoparticles with intermittent ozonation for methyl orange dye (40 %). Overall, this study provides evidence that photocatalytic ozonation represents a promising technique for water treatment.

Understanding CaCl2 induces surface gelatinization to promote cold plasma modified maize starch: Structure-effect relations

To investigate the influence of surface gelatinization on cold plasma (CP) modification of starch, this study used CaCl2 to modify maize starch by surface gelatinization, further combined with CP treatment and characterized its multi-scale structure and physicochemical properties. The results revealed that starch surface gelatinization causes roughness and fragmentation on the granule surface, and CP undergoes etching effects. The synergistic modification promotes starch degradation, as evidenced by molecular weight decrease and short-chain ratio increase. Although the growth rings, FT-IR patterns, and crystal types of starch remained unchanged, the synergistic modification induced a reduction in the short-range orderliness and crystallinity of starch, thus causing a decrease in the pasting properties and contributing to its solubility. Notably, the CP treatment improved the RDS and SDS contents of the gelatinized starch due to more active sites on the granule surface after gelatinization, and this finding may provide insight into the deep processing of starch.

Limitation of the migration of plasticizers from medical devices through treatment with low-pressure cold plasma, polydopamine coating, and annealing

Poly(vinyl chloride) (PVC) is widely used in the manufacture of medical devices. The plasticizers added to PVC are potentially toxic for humans, likely to migrate, and thus unintentionally administered to patients. The objective of the present study was to reduce the migration of plasticizer (1,2-cyclohexanedicarboxylic acid, diisononylester (DINCH) or trioctyltrimellitate (TOTM)) from PVC by implementing a three-step surface treatment process: (i) pretreatment with low-pressure argon cold plasma, (ii) polydopamine coating, and (iii) post-treatment with cold plasma exposure or thermal treatment at 140 °C. Samples were then characterized in terms of the water contact angle (WCA) and the aspect in scanning electron microscopy. Plasticizer migration (n = 5) was measured using an HPLC technique with ultraviolet detection and found to depend on the treatment and the plasticizer. Plasticized PVC was hydrophobic, with a measured mean ± standard deviation WCA of 96.7 ± 3.6° for PVC-DINCH and 110.2 ± 5.8° for PVC-TOTM. Plasma post-treatment and thermal post-treatment were respectively associated with a mean decrease in migration of 38.3 ± 1.9% for DINCH and 61.5 ± 4.4% for TOTM. Our results are promising with regard to limiting the migration of plasticizers into the patient's blood and thus enabling the development of safer medical devices.

Influence of plasma on adsorptive and stabilizing properties of the system

The paper presents the studies on the processes at the interface of the colloidal suspensions composed of clay mineral - glauconite (GT) and polysaccharide - sodium carboxymethyl cellulose (NaCMC) with the cold plasma treatment (CPT). The surface composition and chemical binding in NaCMC and GT changes are determined by means of FTIR and XPS (both methods detected the incorporation of oxygen-related functional groups). Moreover, the additional information about both the textural properties and morphological changes on the surfaces before and after CPT are studied using the BET, CHN, SEM HRTEM and STEM-EDS methods. The elemental mapping and scanning electron microscope imaging confirmed the NaCMC adsorption on GT (carbon mapping) and proved the GT surface lost its "house of card structure" after the CPT. As follows the CPT causes the protonation of NaCMC and the polymer cross-linking whereas the GT sample is more oxidized. Moreover, it was found that a significant improvement in the GT/NaCMC system stability and the NaCMC adsorption on the GT surface were a result of the CPT. The obtained data could be used for the colloidal stability of polymer/solid suspensions, thus providing new opportunities for the chemical industry; particularly for preparation of new functionalized materials.

Atmospheric pressure pin-to-plate cold plasma effect on physicochemical, functional, pasting, thermal, and structural characteristics of proso-millet starch

The present work aimed to study the influence of atmospheric pressure pin-to-plate cold plasma on the physicochemical (pH, moisture, and amylose content), functional (water & oil binding capacity, solubility & swelling power, paste clarity on storage, pasting), powder flow, thermal and structural (FTIR, XRD, and SEM) characteristics at an input voltage of 170-230 V for 5-15 min. The starch surface modification by cold plasma was seen in the SEM images which cause the surge in WBC (1.54 g/g to 1.93 g/g), OBC (2.22 g/g to 2.79 g/g), solubility (3.05-5.38% at 70 °C; 37.11-52.98% at 90 °C) and swelling power (5.39-7.83% at 70 °C; 25.67-35.33% at 90 °C) of starch. Reduction in the amylose content (27.82% to 25.07%) via plasma-induced depolymerization resists the retrogradation tendency, thereby increasing the paste clarity (up to ̴ 39%) during the 5 days of refrigerated storage. However, the paste viscosity is reduced after cold plasma treatment yielding low-strength starch pastes. The relative crystallinity of starch increased (37.35% to 45.36%) by the plasma-induced fragmented starch granules which would aggregate and broaden the gelatinization temperature, but these starch fragments reduced the gelatinization enthalpy. The fundamental starch structure is conserved as seen in FTIR spectra. Thus, cold plasma aids in the production of soluble, low-viscous, stable, and clear paste-forming depolymerized proso-millet starch.

Radical adducts formation mechanism of CH3CO2∙ and CH3CO3∙ realized decomposition of chitosan by plasma catalyzed peracetic acid

High-molecular-weight chitosan has limited applications due to unsatisfactory solubility and hydrophilicity. Discharge plasma coupled with peracetic acid (PAA) oxidation ("plasma+PAA") realized fast depolymerization of high-molecular-weight chitosan in this study. The molecular weight of chitosan rapidly declined to 81.1 kDa from initial 682.5 kDa within 60 s of "plasma+PAA" treatment, and its reaction rate constant was 12-fold higher than single plasma oxidation. Compared with 1O2, ∙CH3, CH3O2·, and O2∙-, CH3CO2∙ and CH3CO3∙ played decisive roles in the chitosan depolymerization in the plasma+PAA system through mechanisms of radical adduct formation. The attacks of CH3CO2∙ and CH3CO3∙ destroyed the β-(1,4) glycosidic bonds and hydrogen bonds of chitosan, leading to generation of low-molecular-weight chitosan; the main chain structure of chitosan was not changed during the depolymerization process. Furthermore, the generated low-molecular-weight chitosan exhibited greater antioxidant activities than original chitosan. Overall, this study revealed the radical adduct formation mechanisms of CH3CO2∙ and CH3CO3∙ for chitosan decomposition, providing an alternative for fast depolymerization of high-molecular-weight chitosan.

Enhanced properties of non-starch polysaccharide and protein hydrocolloids through plasma treatment: A review

Hydrocolloids are important ingredients in food formulations and their modification can lead to novel ingredients with unique functionalities beyond their nutritional value. Cold plasma is a promising technology for the modification of food biopolymers due to its non-toxic and eco-friendly nature. This review discusses the recent published studies on the effects of cold plasma treatment on non-starch hydrocolloids and their derivatives. It covers the common phenomena that occur during plasma treatment, including ionization, etching effect, surface modification, and ashing effect, and how they contribute to various changes in food biopolymers. The effects of plasma treatment on important properties such as color, crystallinity, chemical structure, rheological behavior, and thermal properties of non-starch hydrocolloids and their derivatives are also discussed. In addition, this review highlights the potential of cold plasma treatment to enhance the functionality of food biopolymers and improve the quality of food products. The mechanisms underlying the effects of plasma treatment on food biopolymers, which can be useful for future research in this area, are also discussed. Overall, this review paper presents a comprehensive overview of the current knowledge in the field of cold plasma treatment of non-starch hydrocolloids and their derivatives and highlights the areas that require further investigation.

Chemical alterations of grain surface by cold plasma technology: Comparison of buckwheat and wheat grain responses to oxygen low-pressure plasma

Cold plasma (CP) has a great potential for decontamination or improvement of grain germination. However, disputing results have been reported, as plasma treatment can affect species and varieties of grains in different ways. The differences may be due to the chemical composition of grain pericarps, the structure of the grains and metabolic response mechanisms. CP treatment decreased grain germination rate, speed and activity of α-amylase of buckwheat grains. Such effects on both varieties of wheat grains were present after longer exposure to plasma. Lipid peroxidation was highest in buckwheat grains, whereas wheat grains were less affected. Plasma-treated Gorolka variety exhibited a low level of lipid peroxidation, no different to untreated grains, compared to Primorka grains, where longer treatment triggered higher levels of lipid peroxidation. The response of grains to CP treatment depends on the chemical and structural properties of grains pericarp, as well as plant tolerance to certain abiotic conditions.

Cold plasma approach fortifies the topical application of thymoquinone intended for wound healing via up-regulating the levels of TGF-ß, VEGF, and α-SMA in rats

Wound healing is a series of coordinated events that involve tissue repair and regeneration. Cold atmospheric plasma approach sheds the light on the mechanism that initiates the inflammatory responses throughout the healing cascade. The present study was planned to assess the effect of thymoquinone treated with cold plasma (TQcp) on the rat wound model compared to thymoquinone (TQ). To assess the wound healing potential of TQcp, a full-thickness wound model was used. The induced wound was smeared, starting just after excision, twice daily with TQcp and TQ for 7 days. Our findings revealed that TQcp improved the skin healing potential by augmenting the skin regeneration indices as evidenced by enhancing the new production of hyaluronic acid and collagen type I. TQcp significantly reduced the skin content of tumor necrosis factor- α and inhibited the hypertrophic scarring by up-regulating the skin content of transforming growth factor-beta. Furthermore, TQcp enhanced the levels of interleukin-10, alpha smooth muscle actin and vascular endothelial growth factor, demonstrating a great potential for wound healing that also reflected in the histopathological and ultra-structural picture of the skin. Finally, our results demonstrated that TQcp revealed a significant potential for wound healing than TQ alone.

Effects of pin-to-plate atmospheric cold plasma for modification of pearl millet (Pennisetum glaucum) starch

The present study was done to analyze the effect of atmospheric pressure non-thermal pin-to-plate plasma at a range of different voltages (170, 200, and 230V) at different time intervals (10, 20, and 30 mins) on under-utilized pearl millet starch. The untreated and treated starches were analyzed for amylose content, pH, carbonyl, and carboxyl group, reducing sugar, turbidity, water, and oil binding property, pasting property, DSC, FTIR, XRD, and molecular weight. As cold plasma contains highly reactive species and free radicals, it is expected to cause noticeable modifications in the attributes of treated starch. There has been a significant reduction (p < 0.05) in turbidity value by 38.97% and pH value of starch from 6.49 to 4.05. Plasma-treated samples produced clearer pastes with higher stability over storage time. Cold plasma treatment also led to an increase in the ζ potential. However, there has been no significant change in the water activity and oil-binding capacity of the starch. Reducing sugar content, average molecular weight, degree of polymerization, pasting property, XRD, and FTIR data confirmed that cross-linking takes place in samples treated at lower voltages and lesser time followed by depolymerization occurring in harshly treated plasma samples. The study thus points out the possible use of cold plasma for starch modification to produce starches with altered properties.

Insight into the microorganisms, quality, and protein structure of golden pompano (Trachinotus ovatus) treated with cold plasma at different voltages

Cold plasma (CP) is a non-thermal novel technology for the processing of heat-sensitive food products, but there is concern regarding its impact on food quality. Voltage is one of the most direct factors affecting the bacteriostatic effect of CP. Golden pompano (Trachinotus ovatus) was treated with CP at different voltages (10, 20, and 30 kV). The total viable count decreased as the CP voltage increased, reaching a maximum reduction of 1.54 lg CFU/g on golden pompano treated at 30 kV. No effects on water-holding capacity, pH, total volatile base nitrogen, and T_2b relaxation time were observed, indicating that all CP treatments retained the freshness and bound water of the samples. However, as the CP voltage increased, peroxide value and thiobarbituric acid-reactive substances of golden pompano gradually increased, the protein tertiary structure unfolded, and α-helices converted to β-sheets, indicating inevitable lipid and protein oxidation caused by excessive CP voltage. Therefore, a suitable voltage of CP should be selected to inhibits the growth of microorganisms, which avoids deterioration of sea-foods quality.

Effects of emerging food pretreatment and drying techniques on protein structures, functional and nutritional properties: An updated review

Protein is one of the most important components of food which significantly contributes to the structure, functionality, and sensory properties which may affect consumer acceptability of processed products. Conventional thermal processing affects protein structure and induce undesirable degradation of food quality. This review provides an overview of emerging pretreatment and drying technologies (plasma treatment, ultrasound treatment, electrohydrodynamic, radio frequency, microwave, and superheated steam drying) in food processing by assessing protein structural changes to enhance functional and nutritional properties. In addition, mechanisms and principles of these modern technologies are described while challenges and opportunities for the development of these techniques in the drying process are also critically analyzed. Plasma discharges can lead to oxidative reactions and cross-linking of proteins that can change the structure of proteins. Microwave heating contributes to the occurrence of isopeptide or disulfide bonds which promotes α-helix and β-turn formation. These emerging technologies can be adopted to improve protein surface by exposing more hydrophobic groups which restrict water interaction. It is expected that these innovative processing technologies should become a preferred choice in the food industry for better food quality. Moreover, there are some limitations for industrial scale application of these emerging technologies that need to be addressed.

Atmospheric cold plasma induced nutritional & anti-nutritional, molecular modifications and in-vitro protein digestibility of guar seed (Cyamopsis tetragonoloba L.) flour

The present study was carried out to investigate the effect of atmospheric cold plasma treatment on the nutritional, anti-nutritional, functional, morphological, and digestibility of guar seed (Cyamopsis tetragonoloba L.) flour. Here, guar seed flour was kept inside the plasma reactor for 5 to 20 min at different power levels (10 & 20 kV). The cold plasma treatment (CPT) significantly (p < 0.05) reduced the carbohydrate (46.87 - 36.81 %), protein (27.15 - 25.88 %), and increased the WAC (1.89 - 2.91 g/g), OAC (1.18 - 2.17 g/g), FC (113 - 186.17 %), and pasting properties of guar seed flour. High-intensity plasma-treated samples (20 kV-20 min) contained lesser tannin, phytic acid, and saponin with reduced the nutritional value. The FTIR spectrum suggested that functional group formation or destruction might have occurred in the plasma-treated samples. Additionally, the crystallinity is reduced with increasing applied voltage or duration. The SEM analysis reveals that CPT resulted in the formation of rough surfaces with highly porous structures. On the other hand, CPT significantly reduced the trypsin inhibitor activity and had a minor impact on in-vitro protein digestibility except for the 20 kV-20 min treated sample. In PCA analysis, 10 kV-15 min treated samples exhibited better nutritional value, functional, and pasting properties with maximum impact of anti-nutritional factors. From the results, it can be concluded that treatment duration rather than the applied voltage plays a significant role in preserving the nutritional content.

Partial hydrogenation of oils using cold plasma technology and its effect on lipid oxidation

The formation of trans-fatty acids during the hydrogenation of oils using traditional methods is a known fact. Hydrogenation involves the conversion of unsaturation to saturation to enhance the keeping quality of oils. These trans-fatty acids are considered harmful leading to several cardiovascular diseases. Methods like the use of novel catalysts, interesterification, supercritical CO2 hydrogenation and electrocatalytic hydrogenation have been employed to reduce the trans-fatty acid formation. Recently, the application of cold plasma for hydrogenation was employed as an eco-friendly technology. The use of hydrogen as a feed gas will be the source of atomic hydrogen required for the conversion of unsaturated to saturated bonds. The hydrogenation using cold plasma did not result in the formation of trans-fatty acids. However, some reports have shown insignificant levels of trans-fatty acids and secondary lipid oxidation compounds after the plasma treatment. Therefore, it is necessary to optimize the plasma parameters, feed gas type and composition, processing condition to avoid practical implications. It can be concluded that after the detailed investigation of role of reactive species in the partial hydrogenation of oils cold plasma can be considered as an alternative technology.

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.

Effect of atmospheric pin-to-plate cold plasma on oat protein: Structural, chemical, and foaming characteristics

The impact of novel pin-to-plate atmospheric cold plasma was investigated with input voltage (170 V, 230 V) and exposure time (15 & 30 min) on oat protein by studying structural (FTIR, circular dichroism (CD), UV-vis, Fluorescence), morphological (particle size analysis, SEM, turbidity), chemical (pH, redox potential (ORP), ζ potential, carbonyl, sulfhydryl, surface hydrophobicity), and foaming characteristics. The plasma treatment reduced the pH while increasing the ORP of the dispersions. These ionic environment changes affected the ζ potential and particle size leading to the formation of larger aggregates (170-15; 230-15) and distorted smaller ones (170-30; 230-30) as confirmed by SEM. The FTIR spectra showed reduced intensity at specific amide bands (1600-1700 cm^-1) and also an increase in carbonyl stretching (1743 cm^-1) representing oxidative carbonylation (increase in carbonyl content). Thus, the partial exposure of hydrophobic amino acids increases surface hydrophobicity. The altered secondary structure (rise in α-helix, decrement in β-sheets and turns), and tertiary structures were observed in circular dichroism (CD) and UV absorbance and fluorescence characteristics of proteins respectively. Furthermore, the increase in free sulfhydryl content and disulfide content was highly affected by the plasma treatments due to observed protein unfolding and aggregations. Besides, the increased solubility and reduced surface tension contributed to the improved foaming characteristics. Thus, plasma processing influences protein structure affecting their characteristics and other functionalities.

Efficacy of periodic cold plasma treatment in a paddy to produce white-core grains in brewer's rice cultivar Yamadanishiki

We investigated the effect of cold plasma application on the yield and grain quality of rice (Oryza sativa L.), focusing on the brewer's rice cultivar, Yamadanishiki. Two treatment methods were examined in a paddy; direct plasma irradiation of seedlings and indirect treatment with plasma-activated Ringer's lactate solution (PAL) during the vegetative growth phase. Periodic direct irradiation for 30 s increased whole plant weight and grain yield. Treatment with PAL promoted some growth of panicles relatively and partially suppressed the growth of culms and leaves. Both treatments affected the grain quality; an increase of the ratio of white-core grains to total number of grains, which is suited for producing Japanese sake rice, as well as a decrease of the ratio of immature grains. The results showed that the effective production of rice grains for sake production can be improved by the application of cold plasma treatment of rice seedlings in a paddy.HighlightRice plants of brewer's rice cultivar in a paddy were treated with cold plasma, by the direct irradiation of plants and the immersed of plants in plasma-activated Ringer's lactate (PAL).Direct plasma irradiation promoted plant weight, grain ripening, and increased yield.PAL treatment affected the growth of main stem, and promoted the growth of panicles relatively.Both treatments improved the producing white-core grains, in addition to promotion of grain ripening.Cold plasma treatment can be applied to produce stable and high-quality food in various agriculture and food industries, which can achieve the sustainable developmental goals (SDGs).

Plasma-microbubble treatment and sustainable agriculture application of diclofenac-contaminated wastewater

The demand for efficient wastewater treatment is becoming increasingly urgent due to the rising threat of pharmaceutical residues in water. As a sustainable advanced oxidation process, cold plasma technology is a promising approach for water treatment. However, the adoption of the technology encounters several challenges, including the low treatment efficiency and the potentially unknown environmental impact. Here, microbubble generation was integrated with cold plasma system to enhance treatment of wastewater contaminated with diclofenac (DCF). The degradation efficiency depended on the discharge voltage, gas flow, initial concentration, and pH value. The best degradation efficiency was 90.9% after 45 min plasma-bubble treatment under the optimum process parameters. The hybrid plasma-bubble system exhibited strongly synergistic performance heralded by up to seven-times higher DCF removal rates than the two systems operated separately. The plasma-bubble treatment remains effective even after addition of SO₄^2-, Cl^-, CO₃^2-, HCO₃^-, and humic acid (HA) as interfering background substances. The contributions of •O₂^-, O₃, •OH, and H₂O₂ reactive species to the DCF degradation process were specified. The synergistic mechanisms for DCF degradation were deduced through the analysis of the degradation intermediates. Further, the plasma-bubble treated water was proven safe and effective to stimulate seed germination and plant growth for sustainable agriculture applications. Overall, these findings provide new insights and a feasible approach with a highly synergistic removal effect for the plasma-enhanced microbubble wastewater treatment, without generating secondary contaminants.