Effect Of Ozone Treatment Research Articles

Effect of Ozone Treatment and Storage Temperature on Physicochemical Properties of Mushrooms (Agaris bisporus)

The aim of this paper was to determine the effect of ozone, storage time and temperature on postharvest quality of mushroom ( Agaris bisporus var. Gurelan 55). Mushrooms, treated with ozone (100 mg/h) during 0, 15 or 25 minutes, were packed in polystyrene packs, overwrapped with PVC plastic film, and stored at 5, 15 or 25 °C for seven days. Internal and external lightness ( L*) texture properties, maturity index and weight loss were analyzed during storage. Ozone treatment on mushrooms prior to packaging caused an increase in external browning rate and a reduction of the internal browning rate. The ozone treatment exhibited no significant differences in terms of texture, maturity index and weight loss of mushrooms. Increased storage time and temperatures meant an increase in browning, senescence and weight loss, as well as a decrease in firmness, following, in all cases, a zero-order reaction kinetics. Temperature dependence of the reaction rates coule be described by Arrhenius equation. Among all the quality parameters assessed in this research, weight loss was the most affected by temperature increase ( Ea = 17.60 kcal/mol). The lowest storage temperature (5 °C) favored the best quality.

Effect of Ozone Treatment and Storage Temperature on Physicochemical Properties of Mushrooms (Agaris bisporus)

Effect of Ozone Treatment and Storage Temperature on Physicochemical Properties of Mushrooms (Agaris bisporus)

Effects of ozone treatment of 4H–SiC(0001) surface

The effects of high-concentration ozone gas (~25%) exposure at atmospheric pressure with and without ultraviolet (UV) irradiation to a 4H–SiC(0001) surface has been investigated by X-ray photoelectron spectroscopy (XPS). The C 1s XPS spectrum for the 4H–SiC surface after standard RCA cleaning showed the appearance of a chemically shifted peak on the higher binding energy side of the SiC bulk peak. The chemically shifted peak was also observed even for the surface prepared by dipping a sample with sacrificed oxide film into 5% HF solution. Curve-fitting analysis using the Gaussian function revealed that the chemically shifted peak consisted of three components. The chemically shifted peak could be sufficiently eliminated using ozone exposure with UV irradiation. The cleaning mechanism of the 4H–SiC surface by ozone exposure is discussed, referring to the analysis of peak intensity for each component under different surface conditions corresponding to RCA cleaning and ozone exposure with and without UV irradiation.

Changes in carbohydrates, leaf pigments and yield in potatoes induced by different ozone exposure regimes

Potatoes ( Solanum tuberosum cv. ‘Hela’) were exposed in closed fumigation chambers for nine weeks until harvest in 1995. In three treatments ozone was applied as constant concentration (35 ppb for 24 h/d) as well as with peaks (110 ppb for 4 h/d and 65 ppb for 8 h/d) under equal dose conditions. In addition ozone was applied at constant concentration (47, 65 ppb for 24 h/d) in two treatments. In 1996 potatoes were exposed for six weeks and kept until harvest for four weeks in charcoal filtered ambient air (<5 ppb). Ozone was applied as constant concentration (65 ppb for 24 h/d) as well as with peaks (110 ppb for 4 h/d). In both years plants in control chambers were cultivated in charcoal filtered ambient air (<5 ppb). Effects of the different treatments on pigment and carbohydrate (hexoses, sucrose, starch) content in leaves and/or tubers during and after exposure were determined and fresh tuber weight was assessed. Effects on physiological parameters, a decrease in sucrose up to 43% relative to control ( p < 0.05, 65 ppb for 24 h/d) and pigment content up to 25% relative to control ( p < 0.001, 65 ppb for 24 h/d) of leaves were induced after four weeks of exposure. Under equal dose conditions (1995) ozone peaks induced much more pronounced effects on carbohydrate content than constant concentrations. Glucose content in leaves decreased after eight weeks of exposure to 65 ppb (8 h/d) resp. 110 (4 h/d) about 67% ( p< 0.001) resp. 62% ( p < 0.01) in comparison with a decrease of about 43% ( p < 0.05) after exposure to 35 ppb (24 h/d). Similar observations were made with respect to tuber weight which decreased up to 20% ( p < 0.01) after exposure to 110 ppb peaks (4 h/d) and a four week period in charcoal filtered air (<5 ppb). This was similar to the decrease of 26% ( p < 0.001) after exposure to 65 ppb constantly, the daily dose being doubled (1996). The results favour the hypothesis that ozone peaks induce much stronger effects than constant concentrations using the same total dose and that effects of ozone treatment are carried over for weeks in periods of relatively low ozone levels with respect to tuber weight as well as carbohydrate content.

Effect of ozone treatment on reactive oxygen species and adenosine production during hepatic ischemia-reperfusion

This study investigates whether ozone could confer protection from hepatic ischemia reperfusion by modifying the accumulation of adenosine and xanthine during ischemia. A significant increase in both adenosine and xanthine accumulation was observed as a consequence of ATP degradation during hepatic ischemia. Adenosine exerts a protective effect on hepatic ischemia reperfusion injury since the elimination of endogenous adenosine accumulation with adenosine deaminase increased the hepatic injury associated with this process. On the other hand, the high xanthine levels observed after ischemia could exert deleterious effects during reperfusion due to reactive oxygen species generation from xanthine oxidase. The administration of allopurinol, an inhibitor of xanthine oxidase, attenuated the increase in reactive oxygen species and transaminase levels observed after hepatic reperfusion. Ozone treatment in liver maintained adenosine levels similar to those found after ischemia but led to a marked reduction in xanthine accumulation. In order to evaluate the role of both adenosine and xanthine, we tried to modify the protection confered by ozone, by modifying the concentrations of adenosine and xanthine. The metabolization of endogenous adenosine after ischemia abolished the protective effect conferred by ozone. When xanthine was administered previous to ozone treatment, the protection conferred by adenosine disappeared, showing both postischemic reactive oxygen species and transaminase levels similar to those found after hepatic ischemia reperfusion. Ozone would confer protection against the hepatic ischemia reperfusion injury by the accumulation of adenosine that in turns benefits the liver and by blocking the xanthine/xanthine oxidase pathway for reactive oxygen species generation.

Mechanism and effects of ozone treatment for cooling water system

The sole ozone used in cooling water treatment has raised some critical questions concerned with what happens chemically, that may describe why it can control corrosion, scale and microorganism. The pilot cooling tower (PCT) test presented the effects of ozone as a sole cooling water treatment. Except the higher pH and alkalinity in the PCT test, proper residual ozone concentration produced an oxidative film (protective film) on the metal surface of carbon steel, brass and type 316 stainless steel, the corrosion rate may also be decreased. Ozone was still unpredictable for scale control except for the existence of organic matter. The excellent control of fouling was also attained, that could be determined by the presence of ozone. The strong biocide properties of ozone resulted in excellent biological control. A mechanism is proposed to explain the results.

The impact of ozone fumigation and fertilization on chlorophyll fluorescence of birch leaves ( Betula pendula )

The impact of ozone fumigation on chlorophyll a fluorescence parameters and chlorophyll content of birch trees grown at high and low fertilization were studied for 6-, 8-, and 12-week old leaves. Fluorescence parameters were measured with a portable fluorometer with its fibre optics tightly inserted in a gas exchange cuvette at light intensities from 0 to 220 µmol photons m−2 s−1. Ozone caused significant changes of primary photosynthetic reactions: a decrease of the quantum yield of photosystem II and an increase of non-photochemical quenching. In all leaves a biphasic light response of non-photochemical quenching was observed. Ozone fumigation shifted the onset of the second phase from a PFD of about 60 µmol m−2 s−1 to about 30 µmol m−2 s−1. While the fertilizer concentration had no influence on this character, high fertilization supply of plants partially reduced O3-induced damage. The light responses of Ft, Fm′ and NPQ observed in birch leaves grown in O3-free air indicate the existence of at least two different processes governing energy conversion of the photosynthetic apparatus at PS II in the range of PFD 0–200 µmol photons m−2 s−1. The first phase was attributed to a rather slowly relaxing type of non-photochemical quenching, which, at least at low PFD, is thought to be related to a state 1–2 transition. The further changes of the fluorescence parameters studied at higher PFD might be explained by an increase of energy-dependent quenching, connected with the energization of the thylakoid membrane and zeaxanthin synthesis. A major effect of ozone treatment was a lowering of PS II quantum yield. This reflects a reduction of PS II electron transport and corresponds to the reduction of CO2-fixation observed in ozonated leaves.

Effects of rainfall acidity and ozone on foliar leaching in red spruce (Picea rubens)

The effects of acid rain and ozone on the leaching of chemicals from the canopy of red spruce (Picea rubens Sarg.) saplings was measured over a 4-year treatment period. The saplings were exposed to various levels of ozone and to acid rain (pH 3.1, 4.1, and 5.1) using open-top chambers. No effects of ozone treatments on canopy leaching were observed. Significant effects of rainfall pH on canopy leaching of Ca2+ and Mg2+ were observed, and post-hoc analysis indicated that these effects were associated only with the most acidic treatment (pH 3.1). In the low pH treatment (high NO3- and SO42-) significant canopy retention of both NO3- and SO42- were observed. The observed increase in base cation leaching flux from the red spruce canopy in the low pH treatment was particularly prominent early in the growing season (June) probably reflecting incomplete cuticle formation in the young foliage. Although the annual magnitude of extra Ca2+ leaching from the canopy of red spruce trees in the low pH treatment was small relative to the foliar calcium pool (about 10%), if this leaching preferentially depletes a physiologically important pool, it may influence tree health.

Effects of ozone treatment on postharvest strawberry quality.

The effect of ozone treatment on the postharvest quality of strawberry was evaluated. Strawberry fruits (Fragaria x ananassa Duch. cv. Camarosa) were stored at 2 degrees C in an atmosphere containing ozone (0.35 ppm). After 3 days at 2 degrees C, fruits were moved to 20 degrees C to mimic retail conditions (shelf life). The changes in several quality parameters such as fungal decay, color, sugar and acids distribution, and aroma were evaluated during the strawberries' shelf life. Ozone treatment was ineffective in preventing fungal decay in strawberries after 4 days at 20 degrees C. Significant differences in sugars and ascorbic acid content were found in ozone-treated strawberries. At the end of cold storage, the vitamin C content of ozonated strawberries was 3 times that of control fruits. A detrimental effect of ozone treatment on strawberry aroma was observed, with a 40% reduced emission of volatile esters in ozonated fruits.

Protective effect of ozone treatment on the injury associated with hepatic ischemia-reperfusion: Antioxidant-prooxidant balance

The effects of ozone treatment on the injury associated to hepatic ischemia-reperfusion (I/R) was evaluated. Ozone treatment (1 mg/kg daily during 10 days by rectal insufflation) is shown to be protective as it attenuated the increases in transaminases (AST, ALT) and lactate levels observed after I/R. I/R leads to a decrease in endogenous antioxidant (SOD and glutathione) and an increase in reactive oxygen species (H2O2) with respect to the control group. However, ozone treatment results in a preservation (glutathione) or increase (SOD) in antioxidant defense and maintains H2O2 at levels comparable to those in the control group. The present study reports a protective effect of ozone treatment on the injury associated to hepatic I/R. The effectiveness of ozone could be related to its action on endogenous antioxidants and prooxidants balance in favour of antioxidants, thus attenuating oxidative stress.

Effects of ozone treatment on the soil organic matter on contaminated sites

In recent years, the ozone treatment technique has been discussed for remediation of contaminated sites. In this paper, data on the effects of ozonation of soil organic matter in ground and pore waters are presented. An aqueous soil extract was ozonated in a stirred tank reactor and characterized by size-exclusion chromatography with online UV and dissolved organic carbon detection. Additionally, degradation experiments were carried out with these extracts in a bacteria regrowth measurement system. After ozonation, a decrease of the humic acid fraction and a reduction of its average molecular size could be recognized. In contrast to this, there was an increase of the building block fraction and the low molecular acid fraction. These two fractions were readily degradable by microorganisms. Therefore, the bacteria regrowth increased with ozonation time. As a result of this, a fast and high regrowth of bacteria can be expected after the ozone remediation technique has been applied. The UV absorbance of extracts at a wavelength of 254 nm showed no significant changes before and after biological degradation. It can be supposed that the microorganisms were not able to degrade chromophoric groups absorbing at a wavelength of 254 nm.

Biodegradability enhancement of refractory pollutants by ozonation: a laboratory investigation on an azo-dyes intermediate

The effectiveness of ozone treatment for improving the biodegradability of recalcitrant pollutants has been proved by investigating the ozonation reaction of FAST-VIOLET-B (FVB) a bioresistant chemical intermediate of azo-dyes. Laboratory scale experiments have been carried out, at room temperature, by bubbling, for 90 min, ozonated air (9ppmO3/min) into 0.35 1 of an alkaline (pH=11) aqueous solution (50 ppm) of FVB. The experimental results indicate that during the ozonation, even though complete FVB degradation occurs in 10 min, ozone consumption goes on for a further 20 min after which time most degradation reactions are completed. The main ozonation by-products, identified by HPLC, IC, and GC-MS are formaldehyde, acetaldehyde, glyoxal, acetone, acetic-, formic-, oxalic- and carbonic-acid, plus six FVB derivatives scarcely biodegradable. At the end of the ozonation, i.e. after 30 min., the initial values of TOC (35 mgC/l) and COD (103 mgO2/l) are respectively 27 and 25 and correspond to a relative removal of about 23% and 76%. As for FVB solution biodegradability expressed as (BOD5)/(COD) ratio, during the first 10 min its value regularly increases from zero up to a maximum of 0.75 that corresponds to an ozone consumption of 2.4 mg per each mg of organic carbon initially present in the solution.

Effect of ozone treatment on Toxocara canis eggs.

The effect of ozone treatment on the development and viability of Toxocara canis eggs was studied. Despite treatment with ozone, unembryonated T. canis eggs could develop into viable second-stage larvae when assayed by larvae recovery after oral inoculation into mice. The viability of second stage larvae of T. canis was also not affected by ozone treatment. No significant difference was observed in the larvae recovery count and migratory pattern of the ozone-treated larvae and the untreated control because the majority of the larvae were recovered from the liver and lungs on day 2 postinoculation. However, scanning electron microscopy of the ozone treated T. canis eggs showed many blebs on the surface of the protein coat at the basement of the honeycomb-like structures. The honeycomb-like structures on the egg surface were also observed to be distorted after ozone treatment. Thus, in spite of inducing some surface morphological changes on the egg, ozone was observed to have no effect on the viability of the embryonated second stage larvae of T. canis.

Biodegradability enhancement of refractory pollutants by ozonation: A laboratory investigation on an azo-dyes intermediate

The effectiveness of ozone treatment for improving (he biodegradability of recalcitrant pollutants has been proved by investigating the ozonation reaction of FAST-VIOLET-B (FVB) a bioresistant chemical intermediate of azo-dyes. Laboratory scale experiments have been carried out, at room temperature, by bubbling, for 90 min, ozonated air (9ppmO3/min) into 0.35 l of an alkaline (pH=11) aqueous solution (50 ppm) of FVB. The experimental results indicate that during the ozonation, even though complete FVB degradation occurs in 10 min, ozone consumption goes on for a further 20 min after which time most degradation reactions are completed. The main ozonation by-products, identified by HPLC, IC, and GC-MS are formaldehyde, acetaldehyde, glyoxal, acetone, acetic-, formic-, oxalic- and carbonic-acid, plus six FVB derivatives scarcely biodegradable. At the end of the ozonation, i.e. after 30 min., the initial values of TOC (35 mgC/l) and COD (103 mgO2/l) are respectively 27 and 25 and correspond to a relative removal of about 23% and 76%. As for FVB solution biodegradability expressed as (BOD5)/COD) ratio, during the first 10 min its value regularly increases from zero up to a maximum of 0.75 that corresponds to an ozone consumption of 2.4 mg per each mg of organic carbon initially present in the solution.

Effect of ozone treatment on amylases in seawater

Two amylases were used as substrates to estimate the effect of ozone treatment on organic matter in seawater. After reaction with ozonated seawater at 8.9–9.2 mg total residual oxygen (TRO) per litre for 10 min at 25 °C, the protein concentrations of the enzyme solutions decreased to 87.5% for α-amylase and 97.7% for β-amylase, while the enzyme activity dropped dramatically to only 3.7% for α-amylase and 14.9% for β-amylase. These results demonstrate that ozone treatment had a stronger effect on amylase activity than on protein concentration. The gel filtration chromatograms of ozonated amylase, along with the above results, strongly suggest that organic matter in seawater is partially oxidized and converted to other substances, but that complete decomposition or mineralization of proteinous substances may not occur efficiently even at concentrations as high as 8.9–9.2 mg TRO 1 −1. On the other hand, the fact that 50% of α-amylase activity in seawater was lost after reaction with only 0.9 mg TRO 1 −1 for 10 min shows that ozone treatment may influence the activities of many of the enzymes produced by microorganisms, thereby resulting in a decrease in the mineralization rate in marine fish farms and aquaria.

有害物質・障害生物の水環境への影響と制御 Ｍｉｃｒｏｔｏｘ試験による埋立地浸出水の処理性能とその水圏生態系への影響評価

The release of landfill leachate containing toxic substances such as heavy metals and organochlorines may cause adverse environmental effects on aquatic environment. Therefore, it is important to clarify the effects of landfill leachate on aquatic environment based on risk analysis. Chemical analysis of landfill leachate is very difficult to evaluate its potential effects accurately because landfill leachate contains a lot of unidentified substances. It is expected that bioassay procedure can compensate the deficits of chemical analysis for samples like landfill leachate. In order to evaluate treatment performance and biological effects of landfill leachate, we conducted bioassay procedure for the raw landfill leachate collected from a real landfill disposal site and the effluent treated by the biological activated carbon fluidized bed (BACFB) process and ozone treatment using Photobacterium phosphoreum, i.e., Microtox test. Microtox test showed that EC50 for raw landfill leachate was 6.7%, which means the raw landfill leachate to be severe toxic. On the other hand, the effluent treated by BACFB showed little toxicity. In addition, bioassay for the effluent sample concentrated through Sep pak column was also carried out to evaluate the effect of ozone treatment. It was found that ozone treatment of the effluent of BACFB increased toxicity. But, when the effluent of ozone treatment was treated again by BACFB, the toxicity decreased significantly compared to that of the effluent treated by ozone or by BACFB only. This result suggests that the hybrid treatment system with the combination of BACFB and ozone treatment process is efficient to remove toxic substances from landfill leachate.

Effects of ozone oxidation on carbon black surfaces

Surface effects of ozone treatment with a fluidized bed-type reactor on carbon black have been studied. It has been observed that the surface oxygen level is proportional to the total volume of ozone supplied per unit area of carbon black surface. The ozone treatment increases the acidity of the carbon black surface. A limiting pH value has been obtained at a surface oxygen concentration of around 6 at %. The surface oxygen introduced on the carbon black is most likely present as carboxylic acid groups as indicated by both high-resolution X-ray photoelectron spectroscopy and Fourier transform-infrared spectroscopy results. The ozone treatment of a carbon black decreases the tensile strength for a natural rubber (non-polar), but increases the tensile strength for a nitrile butadiene rubber (polar).

Microstructural Change of Pitch derived Carbon Matrix in C/C Composite by Ozone Treatment on Carbon Fiber

The effects of ozone treatment against carbon fiber on the properties of carbon fiber and on the microstructural change of pitch derived carbon matrix composite were investigated. Surface treatment of PAN based and pitch based carbon fibers were carried out by using 4% ozone at 110°C 8 hours. Surface oxidation was proceeded continuously, and it was recognized that fine ditches and functional groups were introduced on the fiber, however obvious degradation of tensile strength was not observed. Surface treatment increased the bonding strength between fiber and pitch derived carbon matrix, then debonding or pealing off was not observed. High density and low contents of closed pore were attained. Especially, in cas of pitch derived carbon fiber it was difficult to distinguish the carbon fiber and the matrix carbon.

Foliar symptoms, ethylene biosynthesis and water use of young Norway spruce (Picea abies (L.) Karst.) exposed to drought and ozone

Four-year old Norway spruce (Picea abies (L.) Karst.) trees were pretreated at low and high water supply, and then placed into a growth chamber containing four compartments so that two levels of ozone exposure, 0.02 and 0.4 Μl l−1, could be replicated. They were exposed to ozone and drought stress for 59 days, and water use was determined by periodic weighing. Small effects of ozone treatment were detected on new shoot dry weight, and water use by trees receiving the high ozone treatment appeared higher. Both visual symptoms and ethylene biosynthesis showed that drought stress reduced damage to trees exposed to high ozone. Ethylene emission and 1-aminocyclopropane-1-carboxylic acid (ACC) levels increased after 18 days of exposure to 0.4 Μl l−1 ozone, while visual symptoms were seen at 30 days. After 59 days of exposure to the combined stresses, ethylene and ACC levels were lower, but showed an ozone x water interaction. Most ethylene and ACC were produced by wet trees at high ozone concentration, but dry trees also had high ethylene and ACC levels at low ozone. Levels of needle malonyl-ACC (MACC) were not significantly affected by treatment, and did not change with time, but root MACC levels, which were twice needle levels, were high in wet trees at high ozone concentration, but also high in dry trees at low ozone concentration. These results suggest that drought stress occurring during ozone exposure could be expected to reduce damage to young Norway spruce, and that this damage may be related to ethylene biosynthesis.

Adsorption Sites for Water on Graphite. 6. Effect of Ozone Treatment of Sample

Adsorption Sites for Water on Graphite. 6. Effect of Ozone Treatment of Sample