In this study, high voltage atmospheric cold plasma (HVACP) with different working gases (air, Ar, He and N2) was used to modify the surface of tomato pomace, aiming to facilitate the migration of ...phenolic compounds during extraction hence increase their extraction efficiency. In addition to rupturing the epidermal cells of tomato pomace, HVACP treatments were found to decrease the water contact angle of tomato peels and accelerate the drying of tomato fruit, indicating that the treated surfaces were more hydrophilic. Tomato pomace treated by He and N2 plasmas showed increased extraction yields of phenolic compounds by nearly 10%, and all HVACP treatments increased the antioxidant capacity of tomato pomace extracts and slightly changed the concentration profile of their phenolic compounds. The developed HVACP pretreatment technology is a promising method for valorizing tomato processing byproducts with high nutritional values.
Tomato pomace is a good source of phenolic compounds, however, the huge amount generated from commercial tomato processing has caused a severe waste problem. Conventional extraction methods for phenolic compounds are generally time-consuming with intensive use of organic solvents that are thus considered not environment-friendly. This new cold plasma pretreatment method can not only help mitigate the environmental burdens associated with agricultural waste management but also convert waste into value-added functional food ingredients and neutraceuticals in a more efficient way.
•Cold plasma treatments enhanced phenolic compounds extraction from tomato pomace through surface modifications•Cold plasma ruptured cell wall structures of tomato pomace•Cold plasma made tomato peel more hydrophilic and accelerated tomato drying•Extracts from plasma-treated tomato pomace had higher total phenolic content and antioxidant capacity•Cold plasma treatments changed phenolic concentration profiles of tomato pomace extracts
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•Atmospheric cold plasma (ACP) technology was introduced to improve the functional properties of zein films.•The surface hydrophilicity and mechanical strength were significantly ...increased after ACP treatment.•The increased surface roughness and enrichment of the oxygen- and nitrogen-containing groups were responsible for this modification.
In the present study, the nonhazardous atmospheric cold plasma (ACP) technique was introduced to improve the surface hydrophilicity and mechanical strength of zein film. The results indicated that the surface hydrophilicity was significantly increased after ACP treatment, with a drop of contact angle from 72.85 ± 2.33° (untreated) to 48.42 ± 1.57° (ACP–60 s). Increased surface roughness and enrichment of the oxygen- and nitrogen-containing groups were responsible for this modification. As the X-ray photoelectron spectroscopy (XPS) results shown, the O1 s and N1 s peak intensity was dramatically enhanced after 30 s ACP treatment with an increased O/C ratio from 0.64 to 1.09. Storage in ambient environment for an extra 24 h of treated film could further reduce the contact angle. With the treatment time extending, enhanced tensile strength (TS) and flexibility were observed in zein films, accompanied by improving thermal properties, which indicated the cross-linking within protein matrix. Moreover, ACP treatment could significantly decrease the water vapor permeability (WVP) due to the increasing tortuosity of the diffusion pathway after plasma treatment. The secondary structure in amide I band (1600–1700 cm−1) indicated that there was a transformation from β-turn and α-helix into β-sheet induced by ACP treatment. This research opens up new opportunities that ACP could be developed as a modification method of zein film for better utilization in packaging industry.
In recent years, cold plasma is one of the expected alternatives for post-harvest treatments and post-harvest management of products. A surface discharge plasma system was used for investigating the ...destruction time of Bacillus cereus, Bacillus coagulans, Bacillus stearothermophilus, and Clostridium botulinum in bottled milk. The simulation was performed by COMSOL a3.5 software for a two-dimensional geometry. The collected experimental data were simulated in COMSOL software. The k factor of microorganism deactivation data was used to validate the simulated data. Results showed that the production of reactive oxygen species during plasma treatment increases with time and extends to the entire container. The concentration of reactive oxygen species (at the output of the plasma probe) at the beginning of the production was high, and at the end when they leave the free surface of the milk, the concentration decreased. Increasing the initial temperature of milk sample, from 50 to 80℃, can cause significant changes in the amount of ozone from 125 mol/m3 to 266 mol/m3, respectively (p <0.05). However, voltage changes in these two temperatures did not show a significant effect on ozone concentration. Also, immediately upon the initiation of plasma treatment, plasma destruction begins where the concentration of active species is higher. It is shown that among the four studied bacteria, Bacillus stearothermophilus has the highest resistance against cold plasma, and after that other bacteria have shown similar resistance. Finally, it can be concluded that the deep plasma treatment in bottle can make it possible to overcome the surface limitation of cold plasma treatment.
Effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Salmonella and the storability of grape tomato were investigated. Grape tomatoes, with or ...without inoculation with Salmonella, were packaged in a polyethylene terephthalate (PET) commercial clamshell container and cold plasma-treated at 35 kV at 1.1 A for 3 min using a DACP system equipped with a pin-type high-voltage electrode. DACP treatment inactivated Salmonella (p < 0.05) without altering the color or firmness of the grape tomatoes (p > 0.05). DACP treatment inactivated Salmonella uniformly in both layers of the double-layer configuration of the grape tomatoes regardless of the position of the tomatoes in each layer. Salmonella was most efficiently inactivated when the headspace to tomato volume ratio of the container was highest. Integration of rolling of tomatoes during treatment significantly increased the Salmonella reduction rates from 0.9 ± 0.2 log CFU/tomato to 3.3 ± 0.5 log CFU/tomato in the double-layer configuration of the tomato samples. Rolling-integrated DACP also initially reduced the number of total mesophilic aerobic bacteria and yeast and molds in the double-layer configuration of tomato samples by 1.3 ± 0.3 and 1.5 ± 0.2 log CFU/tomato, respectively. DACP treatment effectively reduced the growth of Salmonella and indigenous microorganisms at 10 and 25 °C, and did not influence the surface color, firmness, weight loss, lycopene concentration and residual ascorbic acid of grape tomatoes during storage at 10 and 25 °C. DACP treatment holds promise as a post-packaging process for improving microbial safety against Salmonella and storability of fresh grape tomatoes.
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•Atmospheric cold plasma treatment (ACPT) inactivates Salmonella on grape tomatoes.•A higher container headspace to tomato volume ratio results in higher inactivation.•Inactivation is uniform with tomatoes in a 2-layer configuration in the container.•Rolling of samples during ACPT increases Salmonella reduction rates.•ACPT inhibits microbial growth during storage without affecting quality.
Cold plasma treatment (CPT) was investigated as a nonthermal method for inhibiting Penicillium italicum and improving storability of mandarins (Citrus unshiu Marc.). Whole mandarin fruits or the ...peels were treated with cold plasma at 0.7kPa using a microwave CPT system. The treatment variables were plasma-forming gases, plasma generation power, and treatment time. Nitrogen (N2)-CPT at 900W for 10min, resulted in the highest inhibition of P. italicum (84% reduction in disease incidence), significantly increased the total phenolic content and antioxidant activity of mandarin peel after the treatment (p<0.05), but did not significantly affect CO2 generation, weight loss, content of soluble solids, titratable acidity, pH, ascorbic acid concentration (flesh), or surface color during storage at 4 and 25°C. These results demonstrate the potential for CPT application as a postharvest technology for preserving mandarins, increasing the total phenolic content and antioxidant activity of mandarin peel.
•Cold plasma treatment (CPT) effectively inhibited P. italicum on mandarins.•Plasma generation power and treatment time affected P. italicum inhibition by CPT.•CPT did not alter ripening or quality degradation processes of mandarins.•CPT increased the total phenolic contents and antioxidant activity of the peel.•CPT has the potential for use as a postharvest technology for preserving mandarins.
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•N2/He+ interaction comes into play when cold rare-gas plasmas leave the interior of their generators and get into contact with environment species.•Cold-plasmas exhibit useful ...properties in medicinal applications, surface treatment, food storage, and/or spacecraft propulsion.•The main goal of the present study is to perform a comprehensive series of test electronic-structure calculations using various ab initio approaches in order to (mainly) assess the reliability of employed methods and their practicability in dynamical calculations.
As a first step towards realistic modeling of transport properties of the N2+ ion in helium gas, detailed investigations of the electronic structure of the ion as well as the N2+/He collision complex have been performed with the main focus on computational efficiency and accuracy. A broad range of correlation consistent basis sets and representative orbital spaces have been considered for both computationally cheap multi-configuration self-consistent field (MCSCF) methods and benchmark multi-reference configuration interaction (MRCI) approaches. It has been found that the computationally advantageous MCSCF approach, even if combined with basis sets of moderate sizes, leads to an acceptable accuracy and is thus suitable for direct dynamics simulations of N2+/He collisions to be addressed in subsequent works.
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•Cold plasma is a novel technology with great potential in the food processing field.•Cold plasma is a promising technique for improving the biological activity of foods.•Reduction of ...food allergens & mycotoxins by cold plasma is possible.•Deep research is required to understand the mechanism of cold plasma on nutraceuticals.•Optimizing the process to minimize the product-process interactions is necessary.
There is a growing demand for the consumption of nutritious and safe food products. Cold plasma is a novel non-thermal technology that in recent years, has found numerous applications in the food industry. Study on the applications of this technology and its effects on food quality is increasing. Like any other technology, using cold plasma for the processing of foods can be associated with food quality challenges. This paper reviews the effect of cold plasma on the chemical structure of different food constituents as well as its influence on food characteristics. The emphasis is on the recent studies about the plasma mechanisms of action and chemical alterations of different food components. The studies show that the interaction of plasma-reactive species with food components depends on process conditions. Developing the functional characteristics and reducing the anti-nutritional compounds are of promising potentials of cold plasma. Finally, the research gaps, the salient drawbacks, and future prospects of this technology are highlighted.
The huge amount of grape pomace generated along with wine production usually ends up as waste or with low economic value. However, due to the high content of phenolic compounds, grape pomace can be ...valorized through extraction. This study applied high voltage (60 kV) atmospheric cold plasma (HVACP) as a pretreatment on grape pomace for different time periods (5, 10 and 15 min) to assist in its phenolic compounds extraction, in terms of extraction yield, and the composition and antioxidant capacity of grape pomace extract. HVACP treatment was found to disrupt the epidermal cell structures of grape pomace, reduce the water contact angle of grape peels, as well as accelerate grape drying, and the effects became more significant as treatment extended. HVACP treatment also increased the yield of phenolic extracts, by 10.9–22.8%, which contained a higher concentration of anthocyanins and showed an improved antioxidant capacity (16.7–34.7%). These results demonstrate that the developed HVACP pretreatment can successfully advance the extraction of bioactive compounds by not only increasing their yield but also improving their nutritional quality. This is a promising technology for the winemaking industry to valorize grape processing byproducts for functional food and nutraceutical applications.
•A cold plasma pretreatment method was developed for phenolic compounds extraction from grape pomace.•Cold plasma caused structural damage to cell wall of grape pomace.•Cold plasma increased grape peel hydrophilicity and drying rate of grapes.•Treating grape pomace with cold plasma increased extraction yield of phenolic compounds.•Extracts from cold plasma-treated grape pomace had higher antioxidant capacity and different phenolic compositions.
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