Chia seeds (CS) were subjected to atmospheric pressure cold plasma jet (APCPJ) for different times (30, 60, and 120 s) by using argon gas, and then chia mucilage (CM) was extracted from the seeds to ...investigate the technological properties of mucilage (a heteropolysaccharide). The gel samples prepared from dried CM obtained from CS treated with 30 s and 120 s APCPJ showed noticeably higher consistency index of 11.43 and 13.63 Pa.sn, while the control and 60 s APCPJ showed a lower consistency index of 1.07 and 0.35, respectively. Herschel-Bulkley was better at defining the flow behavior of CM gels, and the treatment increased the shear-thinning and consistency properties. Moreover, CM gels of APCPJ-treated seeds (30 s and 120 s) showed higher elastic properties and better resistance against deformation. The treatment induced cross-linking between polysaccharide chains as confirmed by FTIR, and SEM micrographs demonstrated that APCPJ caused etching on the surface of seeds, thus a more compact structure was obtained in the hydrated mucilage samples depending on the APCPJ time. The highest treatment time (120 s) decreased the solubility, and the water (15%) and oil holding capacity (25%), while it did not significantly affect the emulsion ability and stability. In conclusion, it was found that the APCPJ improved the viscosity and elastic features of CM gels by cross-linking and strengthening the polymer network, which may provide opportunities to use this gum in new food applications.
•Cold plasma (CP) treatment of chia seeds altered the properties of seed mucilage.•CP improved the viscosity and elastic-like behavior of extracted mucilage.•FTIR results confirmed that CP induce cross-linking between polysaccharide chains.•CP modified the surface morphology of both the seeds and the mucilage samples.
Internal shocks between propagating plasma shells, originally ejected at different times with different velocities, are believed to play a major role in dissipating the kinetic energy, thereby ...explaining the observed light curves and spectra in a large range of transient objects. Even if initially the colliding plasmas are cold, following the first collision, the plasma shells are substantially heated, implying that in a scenario of multiple collisions, most collisions take place between plasmas of non-zero temperatures. Here, we calculate the dynamical properties of plasmas resulting from a collision between arbitrarily hot plasma shells, moving at arbitrary speeds. We provide simple analytical expressions valid for both ultrarelativistic and Newtonian velocities for both hot and cold plasmas. We derive the minimum criteria required for the formation of the two-shock wave system, and show that in the relativistic limit, the minimum Lorentz factor is proportional to the square root of the ratio of the initial plasmas enthalpies. We provide basic scaling laws of synchrotron emission from both the forward and reverse-shock waves, and show how these can be used to deduce the properties of the colliding shells. Finally, we discuss the implications of these results in the study of several astronomical transients, such as X-ray binaries, radio-loud quasars, and gamma-ray bursts.
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•Anti-biofilm coatings were plasma-polymerized on stainless steel surfaces.•The best coatings combined two layers (2 precursors): a base and an upper functional.•The biofilm ...production by Listeria monocytogenes was reduced by 90%.•The best anti-biofilm effects were achieved at 12 °C (food processing conditions).•Low roughness and high hydrophilicity can reduce L. monocytogenes adhesion.
Biofilm-mediated microbial persistence of pathogenic and spoilage bacteria is a serious problem in food industries. Due to the difficulty of removing mature biofilms, great efforts are being made to find new strategies to prevent bacterial adherence to surfaces, the first step for biofilm development. In this study, coatings of (3-aminopropyl)triethoxysilane (APTES), tetraethyl orthosilicate (TEOS) and acrylic acid (AA) were applied by Non-Equilibrium Atmospheric Plasma on stainless steel (SS) AISI 316, the SS most commonly used in food industry equipment. Their anti-biofilm activity was assessed against Listeria monocytogenes CECT911 and Escherichia coli CECT515 after incubation at 37 °C. The best results were obtained for L. monocytogenes, with coatings consisting of a base coating of APTES and a functional coating of TEOS (AP10 + TE6) or AA (AP10 + AA6) that reduced biofilm production by 45% and 74%, respectively, when compared with the uncoated SS. These coatings were further characterized, together with a variation of the best one that replaced the acrylic acid with succinic acid (AP10 + SA6). Their anti-biofilm activity was assessed under different incubation conditions, including two strains of L. monocytogenes isolated from processing environments of a meat industry. The coating AP10 + AA6 reduced the biofilm formation by 90% after incubation at 12 °C, a temperature more representative of those commonly found in food processing environments. The morphological and physico-chemical characterization of the selected coatings showed that the coating with the highest anti-biofilm activity (i.e., AP10 + AA6) had lower surface roughness and higher hydrophilicity. This suggests that the formation of a hydration layer prevents the adherence of L. monocytogenes, an effect that seems to be enhanced by low temperature conditions, when the wettability of the strains is increased.
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.
Zinc Selenide Nanoparticles (NPs) were fabricated by the aqueous techneque using cold plasma under atmospheric pressure with an exposure time of 3 min and a gas flow rate of 3 liters per minute. ...films' structural characteristics and morphological characterization were investigated by X-ray diffract meter, atomic force microscopy (AFM), and scanning electron microscopy (FE-SEM). In addition, parameter like crystal size were calculated. Results showed XRD patterns exhibits structure of polycrystalline of preferential orientation (111) direction. SEM technique shows that the nanoparticles presented are spherical. AFM image verified film formed spherical particles distribute uniformly. The antibacterial disc diffusion property of these Nanoparticles, was performed against Gram-negative bacteria of Escherichia coli and Gram-positive bacteria of Staphylococcus aureos, showing good control of said bacteria. The maximum level of inhibition in coli form bacteria with an average inhibition zone diameter with stapheloscous aureous, implying an increasing trend with increasing/decreasing loading volume of NC volume. Therefore, these nanomaterials, which can be prepared in a simple and cost-effective way, may be suitable for new types of germicidal materials.
A nisin-based antimicrobial and cold plasma combination treatments in reducing Listeria monocytogenes inoculated on apple surfaces purchased from a New Jersey farm and a supermarket in Philadelphia ...area was investigated. All apples were spot inoculated or by submersion in 107 CFU/ml L. monocytogenes inoculum. Populations of L. monocytogenes recovered on farm and supermarket apples after spot inoculation averaged 5.8 ± 0.24 log CFU/g and 4.6 ± 0.12 log CFU/g, respectively and 4.1 ± 0.22 log CFU/g and 3.6 ± 0.12 log CFU/g, respectively on submerged apples. All apples were treated with antimicrobial solution for 30 s, 40 s, 3 min (180s) and 1 h (3600 s), cold plasma treatments for 30 and 40s, and a combination of antimicrobial and cold plasma treatments and the surface structure of apples were examined using scanning electron microscopy (SEM). Cold plasma treatment at 40s, followed immediately with antimicrobial treatments at 180s and 3600 s led to 2.5 and 4.6 log CFU/g inactivation of L. monocytogenes, respectively. SEM observation showed changes on apple surface structures but not on bacterial cell structure. This result suggests that this combination treatments is effective in killing L. monocytogenes on apple surfaces.
•Nisin-based antimicrobial and cold plasma treatments combination reduced microbial population on Granny Smith apples.•Individual treatments alone did not cause significant reduction.•The combination treatments for 3 min led to significant reduction listeria monocytogenes.•SEM observation did not show changes cell morphology.
Centella asiatica L. (CA) is a medicinal plant that gained significant commercial and research interest because of its bioactive compounds, which have functional properties such as antioxidant ...activity. However, it must be dried before use to improve its shelf life and prepare it for food and pharmaceutical applications. Therefore, in this investigation CA leaves were pre-treated with blanching and cold plasma activated water (CPAW), followed by recirculatory hot air and vacuum drying at 40, 50, and 60 °C. Vacuum-drying took 150–720 min, while hot-air drying took 60–180 min to dry. Page and Logarithmic models best fit for leaf drying kinetics, according to AIC, with R2 between 0.966 and 0.999 and RMSE between 0.001 and 0.069. CPAW pre-treatment increased leaf quality more than blanching in vacuum drying. Drying leaves at 40 °C boosted antioxidants (4021.462 μg TE (g dw)−1 and 3.356 mg GAEAC (g dw)−1), TPC (35.049 mg GAE (g dw)−1), and TFC (311.274 mg QE (g dw)−1) and is recommended. Vacuum-drying with CPAW pre-treatment preserved leaf microstructure better than hot-air drying. This study illuminates CA leaf drying behaviour and allow mass production without damaging bioactive components. These results could be used as a roadmap for future technological advances that will make it possible to use the bioactive components of CA in food formulation.
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•Cold plasma improves vegetable and fruit quality in a green way.•Plasma-Activated Water was used to pretreat the leaves.•CPAW pretreatment outperformed steam blanching and control.•Page and Logarithmic models fit best for leaf drying kinetics as per AIC.•Desirable changes in product quality and nutritional parameters were observed.
In this study, orange, tomato, apple juices, and sour cherry nectar were exposed to an atmospheric pressure plasma jet. Plasma treatments were carried out using air as a precursor under constant gas ...flow (3000 L/h) at 650 W for different treatment times (30, 60, 90, and 120 s). After plasma processing, reduction of
Escherichia coli
, Hunter’s color parameters (
L*
,
a*
,
b
*), total phenolic content, and pH values were evaluated. The inactivation effect of cold atmospheric plasma (CAP) was investigated on
E. coli
, and the highest significant reductions were achieved in apple juice (4.02 ± 0.03 log CFU/mL) followed by sour cherry (3.34 ± 0.09 log CFU/mL), while the values in orange (1.59 ± 0.17 log CFU/mL) and tomato juices (1.43 ± 0.22 log CFU/mL) were lower, which could be attributed to the food matrix. Color parameters, except for apple juice, did not show significant changes after processing. Compared to untreated juice, plasma treatment yielded higher phenolic content from 10 to 15%, while pH values did not change significantly and the temperature remained below 40 °C after all plasma treatments. This study showed that CAP treatment had positive influences on phenolic stability and color change in all samples regardless of food intrinsic factors, while it was more effective on bacterial inactivation in clear juices than turbid ones. Our results indicate that atmospheric plasma appears to be a promising technology for microbial inactivation without causing undesirable changes in food product.
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•Protein carbonyl content increased after Cold Plasma (CP) treatment in both the isolates.•Functional and emulsification properties of both isolates improved after CP ...treatment.•Circular Dichroism (CD) and Fourier Transform (FT) Raman Spectroscopy confirmed the reduction of α-helix content in isolates.•CP-treated Pea Protein Isolate (PPI) showed better rheological properties and creep recovery than Soy Protein Isolate (SPI).•CP treatment at 30 kV and 6 min gave optimum results for modifying isolates among all the treatments.
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.
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