Impact of Ozonation Process on the Microbiological Contamination and Antioxidant Capacity of Highbush Blueberry (Vaccinum corymbosum L.) Fruit during Cold Storage

In the studies conducted, the impact of the innovative ozonation procedure on the microbial state and antioxidant potential of highbush blueberry (Vaccinum corymbosum L.) stored under cold storage conditions was assessed. Microbiological analysis was carried out to determine the total number of mesophilic aerobic bacteria and the total number of fungi during the storage experiment. In addition, changes in the flavonoid, anthocyanins, and vitamin C content and the total antioxidant capacity were monitored during the storage. The degree of fruit infection with gray mold and anthracnose was determined. It was found that daily ozonation of fruits with a dose of 15 ppm for 30 min, every 12 h, for 28 days effectively reduced the development of aerobic mesophilic bacteria and fungi. On the last day of storage, symptoms of the infection by gray mold were observed in 27.5% of the control fruit, while the absence of symptoms was observed in case of the ozonated fruit. On the other hand, ozone was ineffective in case of inhibiting the infection by anthracnose. Nevertheless, the ozonation process allowed maintaining a high antioxidant potential of the fruit and substantially reduced losses of flavonoids, anthocyanins, and vitamin C. The utilized procedure has proved to be effective, providing the possibility of extensive use of ozone as a factor allowing sustaining a high commercial and consumption value of the fruit over extended time.     

Ozonated Olive Oil with a High Peroxide Value for Topical Applications: In-Vitro Cytotoxicity Analysis with L929 Cells

Previous studies have shown that ozonated vegetable oils have been used topically for healing of cutenous wounds. The aim of this study is to evaluate the dose dependent use of ozonated olive oil with high peroxide value (OZ) on the viability of cells for preventing side effects in topical applications. To the best of our knowledge, there are no reports investigaing the effect of peroxide value of ozonated olive oil associated with its cytotoxic activity on mouse non-neoplastc fibroblast cell lines (L929). Therefore, the present study was carried out by using OZ alone and/or in combination with glycerol and olive oil. In our study OZ was prepared by using pure olive oil. Both olive oil and glycerol are non-toxic and can be mixed with OZ uniformly. The cytotoxic activity of samples against L929 fibroblasts was assessed using the tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assay. The peroxide value of synthesized OZ was found to be in the range of 2700–2900 mEq O₂/kg oil. The OZ/olive oil group did not show any cell death at all concentrations tested (p > 0.05) however OZ/glycerol group showed statistically significant reductions in viability at higher concentrations (p = 0.004–0.006) compared to the control group. Conclusively, using OZ/olive oil with a peroxide value of 2700–2900 mEq O₂/kg oil for short-term incubation was non-cytotoxic to the L929 fibroblast cell line.     

The Effect of Ozone on Aflatoxin M1, Oxidative Stability,Carotenoid Content and the Microbial Count of Milk

In the current investigation, attempts were made to determine if ozone treatment can affect the aflatoxin M₁ (AFM₁) content of milk. Aflatoxin M₁ by a pre-determined concentration of 0.56 μg/Kg was added to milk. Milk samples, were then exposed to gaseous ozone (80 mg/min) in containers for durations of 0, 0.5, 1, 2, 5 and 10 min. The longer exposure time to ozone was more efficient in breaking down the AFM₁ in milk. Results indicated that AFM₁ was reduced by 50%, when milk was ozonated at for 5 min. The pH and oxidation value of milk did not change significanty as a result of the treatments. The β-carotene content was significantly reduced and the total microbial count in milk decreased parallel to the longer exposure time. Also, it was through this longer exposure time by ozone that the L* values of milk increased significantly (p < 0.05), while the b* values significantly decreased. To the best of our knowledge, this is the first study that uses ozone to degrade AFM₁ in milk.     

Effect of Temperature,Modified Atmosphere and Ethylene During Olive Storage on Quality and Bitterness Level of the Oil

Mill olives (Olea europaea L. cv. ‘Lechín’), harvested at the green mature stage of ripening, were stored for 72 h under six different storage conditions: in air, in a closed container, and in a closed container with 30 ppm ethylene either at 20 or at 40 °C. The use of 40 °C as the fruit storage temperature reduced oil bitterness, regardless of the atmosphere applied; however, it also induced a significant reduction in stability and pigment content of the oil extracted. At 20 °C, mill olives stored under air supplemented with 30 ppm ethylene engendered oils with middle bitterness intensity, whereas the oils obtained from fruit stored similarly, but without ethylene, or in an open container exhibited a strong intensity of this sensory attribute. Fruit respiration in the closed containers caused a CO₂ accumulation and an O₂ decrease in the storage atmosphere. This CO₂ concentration was increased by the previous ethylene addition, but O₂ presence did not suffer an additional reduction. The use of modified atmospheres in fruit storage induced off-flavor development in the oils extracted, producing a significant reduction in the overall grading of their sensory quality.     

Role of O3 and OH· Radicals in Ozonated Aqueous Solution for the Photoresist Removal of Semiconductor Fabrication

The role of direct oxidation by aqueous O₃ and advanced oxidation by OH^· in the removal of photoresist was studied by chemical kinetic simulation and experiments of O₃ reactivity and decomposition in homogeneous aqueous solutions. O₃ is the main species responsible for the removal of conventional photoresist in the ozonated water cleaning process, and the timing of initiator addition to ozonated water is important to maintain high O₃ concentration. Simulation using t-butanol implies that maintenance of a high OH^· concentration is required to remove highly implanted photoresists that O₃ itself cannot easily remove.     

Ozone Gas Antifungal Effect on Extruded Dog Food Contaminated with Aspergillus flavus

ABSTRACT

Decontamination of Aspergillus flavus spores in inoculated extruded food (Standard and Super-Premium types), through ozone (O₃) gas, was investigated at different concentrations (40 and 60 µmol/mol) and times (30, 60, and 120 min) of exposure. The gas antifungal efficiency, humidity, and lipid stability were evaluated before and after treatments. O₃ reduced A. flavus spores of the extruded food, on both types (p < 0.05). The highest reduction (98.3%) was observed for both food types, when gas was applied for 120 min, regardless of the O₃ concentration. Regarding humidity and peroxide index, there was no difference, either prior to or after the gas application for all treatments conditions. O₃ gas can be an efficient method for fungi spores’ contamination control during commercialization of extruded food in open bags exposed to the environment.     

Ozone-Based Technologies for Parabens Removal from Water: Toxicity Assessment

Ozone was tested for the detoxification of a mixture of five parabens. A combined O₃/H₂O₂ process was optimized leading to up to 50% of COD removal in 15 min, while less than 50 min were needed to achieve total degradation. The toxic effect of the raw mixture and after 15 min of treatment by O₃/H₂O₂ was evaluated using V. fischeri and C. fluminea and it was observed a strong detoxification after 15 min of oxidation. Moreover, while the raw effluent promoted the formation of reactive oxygen species in Wistar rat brain slices, no changes were observed after the O₃/H₂O₂ treatment.     

The Influence of O2, Hydrocarbons, CO, H2, NO x , SO2, and Water Vapor Molecules on Soot Combustion over LaCoO3 Perovskite

The effect of various gases (O₂, hydrocarbons, CO, H₂, NO _x , SO₂, and H₂O vapor) presenting in the diesel exhaust on soot combustion using LaCoO₃ as a catalytic material was investigated in this paper. A significant promotion of the combustion rate was found following a trend of 10% H₂O addition > 3,000 ppm NO _x  > 1% H₂ or 3,000 ppm C₃H₆ addition, while the improvement in soot oxidation due to the introduction of 3,000 ppm CO or 3,000 ppm CH₄ into the reactant gas is relatively less. The wet pretreatment of LaCoO₃ with 10% steam before soot oxidation hardly affects the combustion behavior. Interestingly, 10% water vapor in the reaction feed produced a significant promoting effect on combustion. In contrast, 30 ppm SO₂ treating led to an obvious deactivation likely owing to the coverage of active sites by sulfate compounds.     

Eightfold increased membrane flux of NF 270 by O3 oxidation of natural humic acids without deteriorated permeate quality

BACKGROUND: Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O₃ oxidation. RESULTS: At a specific O₃ dose of 2.11 g O₃ per g COD (17.0 g m^?3 O₃ (g) for 20 min), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 × 10^?9 L s^?1 m^?2 Pa^?1) than the permeability if the untreated solution is filtered (2.4 × 10^?9 L s^?1 m^?2 Pa^?1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H₂O₂ allows a better mineralization degree, i.e. UVA removal increased from 53% to 66% if H₂O₂ was added as from 10 min oxidation at the same molar flow rate as O₃. CONCLUSION: O₃ oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H₂O₂ can slightly improve its decomposition. Copyright © 2010 Society of Chemical Industry     

Effect of Ozonated Water Treatment on Fatty Acid Composition and Some Quality Parameters of Olive Oil

The organic olives from Çine-Ayd?n (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO₂/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K₂₃₂ and K₂₇₀ values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K₂₃₂ value. Ozonated water washes had almost no effect on fatty acid composition.     

Efficacy of Ozonated Water Against Erwinia carotovora subsp. carotovora in Brassica campestris ssp. chinensis

Erwinia carotovora subsp. carotovora (Ecc) is a bacterial pathogen that causes decay of vegetables and is found in a wide range of Brassica crops in the Shanghai area, particularly in non-heading Chinese cabbage (NHCC). In this study, aqueous ozone was used as an antimicrobial agent to prevent the growth of Ecc bacterial colonies. Ecc that were treated with aqueous ozone were completely inactivated after the bacteria had been exposed to 0.5 mg/L ozone at 28 °C. Furthermore, a susceptible NHCC cultivar was directly sprayed with different concentrations of dissolved ozonated water as a pesticide substitute. The effects of the treatments on morphology were analyzed, and some treatments were characterized by induction of visible symptoms of senescence. No negative effects were observed after treatment by spraying ozonated water compared with the control at concentrations below 8 mg/L. However, visible damage to leaves was observed after the plants were exposed to 10 mg/L ozonated water via spraying for 15 days during the plant reproductive stage. Additionally, enzyme activities and antioxidant responses gradually increased to a certain degree and then decreased in the untreated and ozonated water-treated plants. These results showed that ozonated water was effective in restraining pathogens and potentially defending against disease in growing NHCC plants within a certain concentration range. These results provide a theoretical basis for preventing disease by applying ozonated water to vegetables as an alternative to pesticides.     

An Investigation into the Inactivation Kinetics of Hydrogen Peroxide Vapor Against Clostridium difficile Endospores

C. difficile spores are resistant to routine cleaning agents and are able to survive on inanimate surfaces for long periods of time. There is increasing evidence of the importance of the clinical environment as a reservoir for pathogenic agents and as a potential source of healthcare-associated infections (HCAIs). In this context, to reduce the risk of cross-transmission, terminal disinfection of hospital wards and isolation rooms using hydrogen peroxide vapor (HPV) is attracting attention. Spores of C. difficile (ribotype 027) were exposed to constant concentrations of HPV ranging between 11 and 92 mg m^?3 (ppm) for a range of exposure times in a specially designed chamber. The inactivation data thus obtained was fitted using the modified Chick–Watson inactivation model to obtain decimal reduction values (D values). D values ranged from 23 to 1.3 min at HPV concentrations of 11 and 92 ppm, respectively. We present a simple mathematical model based on the inactivation kinetic data obtained here to estimate the efficacy of commercial HPV processes used in healthcare environmental decontamination. C. difficile spores showed linear inactivation kinetics at steady HPV concentrations ranging between 10 and 90 ppm. The data obtained here was used to provide estimates of the inactivation efficacy of commercial HPV process cycles, which employ unsteady HPV concentrations during the decontamination process.     

The Efficacy of Chlorinated Water Treatments in Minimizing Yeast and Mold Growth in Fresh and Semi-dried Tomatoes

Abstract

A key problem with dried tomatoes for the industries is that the products tend to have limited shelf-life due to yeast and mold growth. This study was undertaken to evaluate the efficacy of chlorine treatments on minimizing yeast and mold populations on fresh and semi-dried tomatoes. Tomatoes were inoculated with molds (4.2 log CFU/g) from contaminated pack of semi-dried tomatoes. These inoculated tomatoes were then treated by washing with water (control) and concentrations of 50, 100, and 200 ppm of chlorinated water for specific length of time (1, 5, and 10 min), and finally analyzed for yeast and mold populations. In this study, the results showed that the maximum log reduction of yeast and mold cells on tomato surface was found to be chlorinated water with a concentration of 200 ppm. At this concentration, washing for 5 and 10 min resulted in 1.7 log reduction and 3.1 log reduction in yeast and mold growth respectively. This was significant (P<0.01) as compared with washing with tap water (control). Drying at 60°C further reduce the microbial load of these pre-treated tomatoes. Results showed that there were reductions in three of the twelve runs while seven of the runs demonstrated an increase in microbial load. This finding is important as it demonstrated that when using a typical drying temperature of 60°C, if the initial microbial load is high, there is a risk that the dehydrator can act as an incubator for more microbial growth. This finding also demonstrated the importance of pretreatment to reduce the initial microbial load before drying commences.     

Bio‐Chemimechanical Pulps from Eucalyptus grandis: Strength Properties,Bleaching, and Brightness Stability

Abstract

Eucalyptus grandis wood chips were treated with the white‐rot fungus Ceriporiopsis subvermispora in a 100‐L bioreactor for 15 days. The treatment was characteristic of a selective biodelignification (7.6±0.2% and 0.3±0.2% of lignin and glucan losses, respectively) with concomitant extractive removal (17.7±0.2%). Biotreated samples and non‐inoculated controls were pre‐cooked in alkaline sulfite and post‐refined in a Jokro mill. The biotreated pulps fibrillated more rapidly and contained lower amounts of rejects than the control. To achieve a freeness of 400 mL, the control pulp required 125 min of beating, whereas the biopulp required only 95 min, a reduction of 24%. Unbleached biopulps had better strength properties than control pulps because higher tensile indexes were obtained for the entire range of tear indexes. Bleaching with 8% hydrogen peroxide increased the brightness of these pulps by 17 points. At low peroxide loads, the brightness increase for biopulps was lower than for the control pulps. Still, the bleachability of sboth pulps was similar for peroxide loads higher than 2%. After a two‐stage H₂O₂‐bleaching sequence, final brightnesses for the control and biopulps were 59.7±0.8% and 60.5±0.4%, respectively. Brightness stability of the bleached control and bio‐CMP pulps to photo and thermal aging were very similar.     

Low-temperature sintering of Ti1−xCux/3Nb2x/3O2 (x = 0.23) microwave dielectric ceramics with CuO and B2O3 addition

The influence of CuO and B₂O₃ addition on the sintering behavior, microstructure and microwave dielectric properties of Ti_1?xCu_x/3Nb_2x/3O₂ (TCN, x = 0.23) ceramic have been investigated. It was found that the addition of CuO and B₂O₃ successfully reduced the sintering temperature of TCN ceramics from 950 to 875 °C. X-ray diffraction studies showed that addition of CuO-B₂O₃ has no effect on the phase composition. The TCN ceramics with 0.5 wt% CuO-B₂O₃ addition showed a high dielectric constant of 95.63, τ_f value of + 329 ppm/°C and a good Q × f value of 8700 GHz after sintered at 875 °C for 5 h, cofirable with silver electrode.     

Optimization of Microwave-Assisted Extraction of Cherry Laurel Fruit

Response surface methodology was used to optimize the influence of microwave power (300–600 W), plant material-to-solvent ratio (0.05–0.2 g/cm³), and extraction time (10–30 min) on the efficiency of microwave-assisted extraction of the cherry laurel (Prunus laurocerasus L.) fruit. From experimental data, a quadratic polynomial mathematical model (R² = 0.9949) was developed to predict the extract yield. All considered factors were statistically significant for extraction efficiency, while the most important factor was extraction time. Microwave power of 550 W, plant material-to-solvent ratio of 0.05 g/cm³, and time of 25 min were determined as optimal conditions with a maximum yield of 9.36 g/100 g fresh plant material, which was confirmed through laboratory experiments (9.12 ± 0.61 g/100 g fresh plant material). An economic condition for simultaneous maximum extract yield (7.58 g/100 g fresh plant material) with minimal energy and solvent consumption was determined by the desirability function method (18.2 min, 300 W, and 0.2 g/cm³). Additionally, the total phenol and flavonoid quantification and antioxidant activity of both extracts were tested. There is no statistically significant difference in the total flavonoid content in the extracts obtained under both proposed conditions, while the total phenolic content and antioxidant activity of the extract obtained under economic conditions were slightly lower.     

Adhesion of conventional and self-adhesive resin cements to indirect resin composite using different surface conditioning methods

This study evaluated the adhesion of conventional and self-adhesive resin cements to indirect resin composite (IRC) using different surface conditioning methods. Cylindrical IRC specimens (N = 192) were randomly assigned to four surface conditioning methods (n = 8 per group): (a) Control group, (b) Hydrofluoric acid, (c) Tribochemical silica-coating, and (d) 50 μm Al₂O₃ air-abrasion. Specimen surfaces were finished using silicon carbide papers up to 600 grit under water irrigation, rinsed and dried. Direct composite blocks were bonded to IRC specimens using three conventional resin cements (Multilink, Panavia F2.0, and Resicem) and three self-adhesive resin cements (RelyX U100, Gcem, Speed Cem). Specimens were subjected to shear bond strength test in a Universal Testing Machine (0.5 mm/min). Failure types were categorized as mixed, adhesive and cohesive. Data were analyzed using 2-way ANOVA and Tukey’s tests. Two-parameter Weibull modulus, scale (m) and shape (0) were calculated. The bond strength results (MPa) were significantly affected by the surface conditioning method (p < 0.0001) and cement type (p < 0.001). For Panavia F2.0, Resicem, air-abrasion with 50 μm Al₂O₃ significantly increased the results (22.6 ± 6.5, 26.2 ± 6.5, respectively) compared to other conditioning methods (13.6 ± 1.4–21.9 ± 3.1) but for Multilink, hydrofluoric acid etching (20.5 ± 3.5) showed significantly higher results (p < 0.01). For the self-adhesive resin cements, air-abrasion with 50 μm Al₂O₃ significantly increased the results compared to other conditioning methods, except for RelyX U100 (p < 0.05). After air-abrasion with Al₂O₃, Gcem, (11.64), RelyX U100 (9.05), and SpeedCem (8.29) presented higher Weilbul moduli. Exclusively cohesive failure in the IRC was observed with RelyX U100 and Speedcem after Al₂O₃ air-abrasion.     

Structure Elucidation and Evaluation of Antioxidant and Tyrosinase Inhibitory Effect and Mechanism of Proanthocyanidins from Leaf and Fruit of Leucaena Leucocephala

This study aimed to investigate the structural features, antioxidant activity, tyrosinase inhibitory effect, and mechanism of proanthocyanidins from leaf and fruit of Leucaena leucocephala. MALDI-TOF-MS, thiolysis coupled with HPLC-ESI-MS, and ¹³C-NMR confirmed that these proanthocyanidins were complex mixtures of propelargonidins, procyanidins, and prodelphinidins. (Epi)catechin, (epi)gallocatechin, (epi)catechin gallate, and (epi)gallocatechin gallate were the main constitutive units. The findings obtained from enzyme analysis revealed that the proanthocyanidins had inhibitory effects on both monophenolase and diphenolase of tyrosinase. The IC₅₀ values of leaf and fruit proanthocyanidins were 73.5?±?2.7 and 52.3?±?3.5 µg/mL for monophenolase activity, and 27.2?±?1.4 and 16.1?±?1.1 µg/mL for diphenolase activity, respectively. The inhibition of diphenolase by proanthocyanidins were proved to be reversible and mixed type. In addition, it was also found from various antioxidant methods that the proanthocyanidins in leaf and fruit possessed potent DPPH radical scavenging activity with IC₅₀ values of 103.4?±?0.8 and 87.8?±?1.1 µg/mL, ABTS radical scavenging activity with IC₅₀ values of 72.9?±?0.4 and 65.7?±?0.9 µg/mL, and ferric reducing antioxidant power with FRAP values of 3.74?±?0.03 and 4.02?±?0.15?mmol AAE/g, respectively. The results obtained suggested that the proanthocyanidins from leaf and fruit of L. leucocephala might have the potential to be exploited as natural tyrosinase inhibitors and antioxidants.     

Energy Conversion and Temperature Dependence in Ozone Generator Using Pulsed Discharge in Oxygen

A detailed reaction kinetic model consisting of 10 species and 63 reactions is developed to investigate the energy conversion and temperature dependence in an ozone generator using oxygen pulsed discharge. The energy conversion ratios of total electric energy converted into reaction heat, heat carried by gas and heat loss to ambient, namely η_reaction, η_gas and η_loss, are obtained for the first time. The ratio of reaction heat η_reaction decreases substantially with increasing specific energy and inlet gas temperature, which represents how much energy is utilized effectively to synthesize ozone. Correspondingly, η_loss and η_gas increase gradually. η_reaction declines from 55.4% to 27.7% at inlet gas temperature of 298 K when specific energy changes from 0.06 J/cm³ to 0.78 J/cm³. The detailed reaction pathway including the degree of transformation among species for ozone formation is also obtained via kinetics simulation. Meanwhile, sensitivity analysis and rate-of-production analysis for the four most important species O₃, O, O(1D) and O₂(b¹∑) obtained from the reaction pathway are executed to understand quantitatively the temperature dependence of sensitivity coefficient and production rate for each individual reaction. The production rate of ozone via the most important ozone generation reaction O+O₂+O₂ = > O₃+O₂ increases linearly with the increase of gas temperature, as well as the destruction rates of ozone via the most important ozone decomposition reactions O₃+O₃ = > O₂+O₂+O₂ and O₃ + O = > O₂(b¹∑)+O₂.     

Effects of a graphene nanosheet conductive additive on the high-capacity lithium-excess manganese–nickel oxide cathodes of lithium-ion batteries

This study examines the effects of a graphene nanosheet (GNS) conductive additive on the performance of a highly packed (2.5 g cm^?3) lithium-ion battery cathode containing 92 wt% Li_1.1(Mn_0.6Ni_0.4)_0.9O₂ microspheres (approximately 6 μm in diameter). GNSs, approximately 2.0 nm thick and 0.5–1.0 μm in width, are introduced into an electrode slurry in the form of a dispersion in N-Methyl-2-pyrrolidone. They are substantially smaller than the oxide particles; therefore, their presence exerts no adverse influence on the packing density of the electrode. A small quantity of the GNS additive (≤200 ppm relative to the oxide mass) can significantly increase the overall electronic conductance and improve the conductance uniformity of the oxide electrode, leading to reduced polarization and enhanced specific capacity and rate performance. However, the GNS additive also promotes solid-electrolyte interphase formation, resulting in resistance buildup and capacity deterioration upon cycling. This study is the first to identify such an adverse effect caused by a graphene additive. The interplay between the positive and negative effects has led to an optimal GNS additive content of approximately 100 ppm, enhancing both the rate and cycle life performance.