Free Radicals

M Aldehydes And Ketones

Figures 4.26, 4.27, and 4.28 show typical UV absorption spectra for some simple aldehydes and ketones (Rogers, 1990 Martinez et al., 1992 see also Cronin and Zhu, 1998, for n-pentanal). Formaldehyde stands out from the higher aldehydes and ketones in that it has a highly structured spectrum and furthermore, the absorption extends out to longer wavelengths. The latter difference is particularly important because the solar intensity increases rapidly with wavelength here (Chapter 3.C.1) and hence the photolysis rate constant for HCHO and the rate of production of free radicals

Results and Discussion

Expression of antioxidants during nodule senescence. Northern hybridization of pea nodule RNA with specific probes for key antioxidant proteins revealed up-regulation of GSH peroxidase (reported for the first time in nodules) and catalase and down-regulation of the other antioxidants during natural (aging) senescence of nodules (Figure 1). Nitrate and dark treatments decreased the transcript abundance of plastidial CuZnSOD, mitochondrial MnSOD, cytosolic APX, and leghemoglobin (used as a control). Nitrate increased the transcript of cytosolic CuZnSOD whereas dark stress decreased it the reverse occurred with ferritin. GSH peroxidase and catalase were up-regulated in both stress conditions. These results indicate that there is differential regulation of antioxidants at the transcript level during the various types of nodule senescence. General features of senescence, however, may be a lowering of important antioxidant defenses and a significant increase of GSH peroxidase and...

Latitudinal and seasonal variability

Aquatic organisms can utilize a number of defense systems to overcome UVR stress (DNA repair, UVR screening, antioxidant enzymes and compounds, see Chapter 10). It can therefore be hypothesized that long term exposure to high incident UVR doses promotes UVR resistance in cells, species, populations or communities. For this reason it can also be hypothesized that organisms inhabiting low latitude regions have developed more efficient UVR defenses than organisms from higher latitudes 17,110,118-120 . Still, recent studies have clearly demonstrated that tropical aquatic organisms also suffer from in situ UVR stress 2,11,52,87,94,102,121 . It remains to be tested whether tropical organisms are more resistant to UVR as compared with organisms inhabiting higher latitudes. Few latitudinal or other large scale comparisons of UV-B vulnerability in aquatic organisms have been carried out 17,122 . One study revealed large differences in UVR vulnerability between regions and seasons 122 , based...

Assessment of Phenylpropanoids in Response to UV

The Williams variety of soybean was used for assessment of individual phenylpropanoids. On Day 7 after planting in darkness, separate growth trays were individually irradiated with 300 nm, 317 nm, 368 nm or Untreated. After irradiation, seedlings were returned to darkness until harvest of the primary leaf material 24 hours later. An analysis of materials produced in response to UV is shown in Table 17.3. All chemicals listed on the left were standardized with purified compounds in order to properly identify metabolites. Data indicate that 300 nm and 317 nm (both in UV-B region) seem to suppress the development of several groups of protective pigments (i.e., anthocyanins, synapic acid, flavanones) and unexpectedly 300 nm does not induce visible synthesis of quercetin. Both 300 nm and 317 nm treatments reduced the production of Phe itself the amino acid that is the precursor to the phenylpropanoid pigments. This may be evidence that young germinating seeds and young seedlings cannot...

Formulation Storage and Quality

The target in developing an ideal formulation is (i) maintenance of quality, (ii) increased storage stability, (iii) low transport cost, and (iv) enhancement of nematode survival during and after application. These can be achieved when absorbents, adsorbents, anticaking agents, antimicrobial agents, antioxidants, surfactants, carriers, preservatives, ultra violet protectants, etc. may be added to the formulation depending upon the need. Formulation of nematodes for storage and transport are generally done by two ways.

Upgrading of the monooligomeric components

16.5.2 Antioxidants Living cells have developed antioxidant systems to protect themselves against the reactive oxygen species. These antioxidants are defined as 'any substance that, when present at low concentration compared to the one of an oxidizable molecule, significantly delays or prevents oxidation of that molecule'. Antioxidants are also of interest in the industry as they minimise the oxidation of lipids in food and non-food matrices. Amongst the anti-oxidants of biological or industrial interest, plant-derived phenolic compounds are the most recently discovered and studied. The structural explanation for the antioxidant properties of these molecules is far from clear. It appears to be partly linked to the ability of hydroxycinnamic acids to donate H+ to form stable phenoxy radicals and to the presence of substitutions on the phenolic ring. The number and position of the hydroxyl and methoxyl groups and the presence of an unsat-urated conjugation system would influence the...

Coproduct recovery in vegetable oil processing

As stated before, vegetable wastewater can be considered as an important source of valuable products, i.e. carbohydrates, phenols, lecithin, vitamin E, sterols and proteins. Visioli et al. (1999), in view of the need for upgrading by-products at all stages of the olive oil industry, investigated different procedures for the recovery of the active components of OMWW and compared the antioxidant and biological activities of various extracts.

Reference Of G N Agrios In Case Of Soil Solarization

Versus conventional farming in southern England. Biol Agric Hort 18 37-54 Carbonaro M, Mattera M, Nicoli S, Bergamo P, Cappelloni M (2002) Modulation of Antioxidant compounds in organic vs conventional fruit (peach, Prunus persica L., and Pear, Pyrus communis L.). J Agric Food Chem 50 5458-5462 Ceuster TJJ, Hoitink HAJ (1999) Prospects for composts and biocontrol agents as substitutes for Nelson EB, Burpee LL, Lawton MB (1994) Biological control of turf-grass diseases. In Leslie AR (ed) Handbook of integrated pest management for turf and ornamentals. Lewis Publishers, Ann Arbor, MI, pp 409-427 Nielsen JH, Lund-Nielsen T, Skibsted L (2004) Higher antioxidant content in organic milk than in conventional milk due to feeding strategy. http www.darcof.dk enews sep04 milk.html Business Cooperative Service. www. a t t r a . o r g Swift MJ, Anderson JM (1993) Biodiversity and ecosystem function in agricultural systems, In Schultze and Mooney (eds) Biodiversity and ecosystem function....

Units of Concentrations and Conversions

A second type of concentration unit is generally used for species such as free radicals (e.g., OH) present at sub-ppt levels. It is the number of molecules, atoms, or free radicals present in a given volume of air, usually a cubic centimeter (cm3). One can convert from units of ppm, pphm, ppb, or ppt to units of number per cm3 using the ideal gas law. Thus the number of moles per L in air at 1 atm pressure and 25 C (298 K) is given by

Examples of phytochemical extracts from plant food wastes

Different extracts obtained from wastes are already in the market or are potential candidates to be in the market soon. From the olive-oil industry wastes, extracts enriched in the antioxidant hydroxytyrosol are already prepared and marketed, as antioxidants for food preservation or as ingredients for functional foods or nutraceuticals (Fernandez-Bolanos et al., 2002). Pomegranate tannins from fruit husks (a mixture of punicalagins and other ellagitannins) can be easily prepared and introduced to the market due to the nutraceutical properties of these metabolites (Gil et al., 2000). Anthocyanin-rich extracts are prepared from grape residues produced in the wine industries. Alternatively, extracts from press-cake residues from the berry-juice industries are also being marketed and these extracts provide, in addition to pigments, an excellent source of flavonols and other phenolics (www.vtt.fi virtual maxfun). Procyanidin extracts from grape seeds are already available in the market,...

Physiological Adaptations In Coastal Vegetation

Coastal Maritime Forest Florida

Tolerance of drought and the ability to regenerate in disturbed sites are two of the outstanding features of sand dune vegetation. Many of the moss and lichen species, which hold the surface of the sand dunes, have the remarkable property of being able to allow their tissues to dry out without losing viability. After prolonged periods of desiccation (e.g. lying on a herbarium sheet for 70 years ) some moss species begin to resume metabolic activity within 30 minutes of gaining access to water. One of the dangers of desiccation injury, especially when plants are exposed to sunlight, is the generation of highly destructive oxygen free radicals by transfer of energy from excited chlorophyll to oxygen. The dune moss Tortula ruraliformis when desiccated in the light has high concentrations of the antioxidants a-tocopherol and glutathione, which may contribute to its remarkable desiccation tolerance (Seel et al., 1992).

Photoprotective mechanisms

Regardless of an organism's efficiency for photorepair such mechanisms are not completely efficient, so do not entirely ensure against potential injury. Therefore, additional protective mechanisms are adaptive. These include pigments that sequester the highly reactive oxygen free radicals or other reactive species that are generated by UV and are responsible for DNA damage and other cellular injuries ( 56 , see also Chapter 8). UV-shielding pigments also provide a means of protection from UV. These can be extrinsic as well as intrinsic filters. Aquatic animals utilize available environmental factors that provide photoprotection, such as DOC, which reduce environmental UV levels, and as a consequence the dose the organism receives. Aquatic organisms also incorporate UV-absorbing or reflective pigments in their integument. tenoids are often distributed throughout the body of copepods, whereas cladocerans tend to concentrate carotenoids in ovarian lipids and eggs 55 . In addition to...

The Effect of Zearalenone in Culture In Vitro

Zearalenone was also found to be more effective than cytokinin treatment in inducing shoots in in vitro winter wheat production. Moreover, both zearalenone and cytokinins increased the activity of antioxidant enzymes in wheat callus undergoing regeneration, and it is very likely that they also stimulated the plant regeneration process (Szechynska-Hebda et al. 2007). The effectiveness of regeneration on media containing zearalenone shows the possibility of using zearalenone as an alternative hormone also to cytokinins in winter wheat callus culture.

Analysis of Metal Cations and Inorganic Anions

Antioxidant Activity Antioxidant activity has been assessed in many ways. In general, the antioxidant effectiveness is measured by monitoring the inhibition of a suitable substrate. After the substrate is oxidized under standard conditions, the extent of oxidation is measured by chemical, instrumental, or sensory methods. Hence, the essential features on any test are a suitable substrate, an oxidation initiator, and an appropriate measure of the end product. Antolovich M. et al. (2002) reviewed the major methodologies for the determination of antioxidant activity used by the food industry, with the diphenylpicrylhydrazyl (DPPH) radical assay being one of the more utilized due to its relative simplicity it is, however, a lengthy procedure. The limitation of many newer methods is the frequent lack of an actual substrate in the procedure. The combination of all approaches with the many test methods available explains the large variety of ways in which results of antioxidant testing are...

Subcategory 1 Tire and Inner Tube Manufacturing

The initial step in tire construction is the preparation or compounding of the raw materials. The basic raw materials for the tire industry include synthetic and natural rubber, reinforcing agents, fillers, extenders, antitack agents, curing and accelerator agents, antioxidants, and pigments. The fillers, extenders, reinforcing agents, pigments, and antioxidant agents are added and mixed into the raw rubber stock. This stock is nonreactive and can be stored for later use. When curing and accelerator agents are added, the mixer becomes reactive, which means it has a short shelf-life and must be used immediately. Emulsion polymerization, the traditional process for synthetic rubber production, is the bulk polymerization of droplets of monomers suspended in water. Emulsion polymerization is operated with sufficient emulsifier to maintain a stable emulsion and is usually initiated by agents that produce free radicals. This process is used because of the high conversion and the high...

Radical Oxygen Species are Unavoidable and Increase During Stress Episodes

Mannitol has been shown in vitro to function as a scavenger of reactive oxygen species, ROS.59-60 ROS is a generic term which is used to include not only free radicals such as superoxide and hydroxyl radicals, but also singlet oxygen and H2O2. Smirnoff and Cumbes26 designed experiments that compared the radical scavenging capabilities of different compatible solutes. They reported that mannitol, sorbitol, glycerol, proline, ononitol and pinitol were active scavengers at different concentrations in vitro, while glycinebetaine was not.26,28 The relative radical scavenging efficiency of these compounds seemed dependent on their rate constants for reactions with hydroxyl radicals. For example, the rate constant of mannitol is four-fold higher than that of proline,61 and thus it was more effective than proline as a hydroxyl radical scavenger. Under water deficit conditions, radical production increases in plants,62 and it may be that the accumulation of polyols provides some protective...

Oxidation with Ozone and Hydrogen Peroxide

During oxidation of organic compounds by means of ozone at high pH, some chain reactions occur that result in hydroxyl radicals, among others. Free radicals are responsible for oxidation of organic substances according to reactions (4) and (5), but the decomposition of organic matter can also be caused by ozone alone 58 . Ozone oxidation requires a high pH carbonate ions will therefore disturb the process since they are scavangers of free radicals. This was described in the discussion of Fenton reagent. For landfill leachate, characterized by COD of 900-2100 mg L, ozone doses are included in the range 1.8-3.5 g O3 g COD. They allow the removal of 25-90 of COD and AOX 67 . Free radicals can also be produced by means of hydrogen peroxide UV irradiation alone, as described in reaction (14) Ozone irradiated with UV light decomposes to oxygen and hydrogen peroxide, which further decomposes to free radicals. Moreover, hydrogen peroxide reacts with ozone, according to summary reaction (13),...

The structural range of plant secondary metabolites

Many flavonoids are highly coloured and are components of flower pigments. Many apparently colourless flavonoids are visible to insects, and play a part in insect pollination. They are highly absorptive in the ultraviolet (UV) and near ultraviolet regions of the spectrum and may have served as protectants from excess UV radiation as plants moved onto land. They are also antioxidants and it was suggested as early as 1969 that they may serve to protect lipids and polyacetylenes in plants from oxidative damage (McClure, 1975). The majority are non-toxic to mammals but have been shown capable of exerting a range of physiological effects, including anti-viral and immune-modulatory activity. Some iso-flavonoids have oestrogenic activity and the group known as rotenones are toxic to insects and fish (Harborne, 1988, 1991). Many phytoalexines, anti-fungal compounds only produced when the plant is damaged or attacked, are isoflavonoids, for example the pterocarpans medicarpin, pisatin and...

Utilizing all the waste

Fish Ensiling

Modern fish meal manufacturing usually consists of several processes coarse grinding, cooking, pressing, drying, stabilizing with antioxidant, and fine milling. In addition, there is often a short curing period which allows the meal to cool down before it is packed into containers for shipment. The liquid that is pressed out of the cooked fish is separated into oil and water streams. The oil becomes a product and, as we will see, the treatment of the water stream (which contains significant amounts of protein) varies, although it is generally evaporated down to a thick paste. One big change in meal production over the last 50 years is the use of antioxidants to prevent oxidation. The long-chain polyunsaturated fatty acids that confer so many benefits on fish oil are extremely prone to oxidation when exposed to heat and oxygen. This causes oxidative rancidity, which makes the meal (or the oil) less appetizing and even harmful in feed. Extreme oxidation may actually cause meal to...

Functional ingredients from meat

Carnosine is a natural antioxidant present in skeletal muscle. A number of patents describe the potential use of carnosine as a therapeutic agent in applications such as wound healing treatment of hypertension and trauma treatment of cataracts and stomach and duodenal ulcers and also as a bactericidal, anti-inflammatory and immunomodulatory agent. A number of cosmetic applications for carnosine (e.g. with respect to skin aging) have also been described. Food applications for carnosine include use in food flavourings (beef brothy) and as an additive to decrease deterioration in foods and discolouration rate of meat (reviewed by James et al., 1995). While meat ingredients have been added to a variety of foods, several functional (i.e. healthy) food ingredients have also been added to meat and meat products. For example, omega-3 fatty acids from fish oils, olive oil, soy proteins, antioxidants such as tea catechins, green tea extracts, phenolic compounds from rosemary, and dietary fibre...

Methods Of Disinfection And Disinfectant Agents Used

Several theories have been proposed as to its mechanics of disinfection, including the production of intermediates and free radicals as the beam hits the water. These intermediates and free radicals are very reactive and are thought to possess the disinfecting power. In sonification, high-frequency ultrasonic sound waves are produced by a vibrating-disk generator. These waves rattle microorganisms and break them into small pieces. Ultraviolet light will be addressed specifically later in this chapter.

Utilizing part of the waste

Fish-liver oils contain fat-soluble vitamins as well as valuable omega-3 fatty acids. The first human health market for fish oils was due to their content of vitamin D and its ability to prevent rickets. A century or more ago, cod fishermen gutted the fish prior to salting, but saved the liver, which was thrown into a 'gurry butt' (see Rudyard Kipling's Captains Courageous for a surprisingly accurate description) and left to rot for the months-long voyage. Those old enough to remember early cod-liver oils will therefore recognize that the nauseating flavor was due to oxidation and impurities as a result of the poor handling. The discovery of effective and rapid methods of oil release and the use of antioxidants has completely changed fish oils, which today are mild-tasting and inoffensive (Stansby, 1990). For those wishing to access the lucrative human supplement market, it is important to recognize that before being enclosed in a capsule, the oil is refined, cook the mince, using...

Key reasons to improve waste management in vegetable oil processing

Vegetable oil wastewaters are rich in organic and inorganic compounds and may also be regarded as an inexpensive source of products to be recovered because of their potential economic interest and or ability to be transformed into products for use in agriculture and industry. OMWW are rich in antioxidant compounds that could be recovered from the matrix and employed both in preservative chemistry and, following appropriate trials to evaluate their safety and efficacy, as prophylactic agents in the prevention of certain radical-induced human diseases. The possibility of isolating natural antioxidants like hydroxytyrosol from wastewater extracts is high. Hydroxytyrosol, the most active component of OMWW extracts, is of particular interest because it is amphiphilic and thus it acts at the oil-water interface and in systems where both oil and water phases are present, such as emulsions (Auroma et al., 1998). Hydroxytyrosol is characterized by a high antioxidant activity, which is...

Plant chemicals in the evolution of mammals and humans

Many plant secondary compounds which appeared to be neither nutritive nor toxic to mammalian predators, for example the ubiquitous flavonoids, are now believed to have subtle beneficial effects in the diet, including a role as scavengers of reactive oxygen species (ROS) and modulators of the immune system. They may have evolved originally in plants to protect them from the effects of ROS generated inter alia through exposure to excess UV light. In mammals ROS are generated as a side reaction of respiration and are normally destroyed by the body's own defences, e.g. by glutathione. They are produced in excess as part of the primary disease process and then go on to cause further tissue injury. A chronic lack of plant-derived antioxidant defences in the modern human diet may be responsible for the rise in many intractable conditions, such as cancer and even AIDS (Halliwell and Cross, 1991).

The Physical Chemistry Properties Of Greenhouse Gases

The second property of interest is the lifetime of the pollutant in the earth's atmosphere the longer the lifetime, the greater contribution a greenhouse gas will make to global warming. The main removal processes in the troposphere and stratosphere are reactions with OH free radicals and electronically excited

Negative Impacts Of Antithamnionella Spirographidis On Biodiversity And Humans

Perception, 438 Anthropogenic activities, 160, 161, 330, 346 Anthropogenic CO2, 121, 360, 367 Anthropogenic disturbance, 129 Anthropogenic influences, 141 Anthropogenic stressors, 26 Anticancer, 388, 389 Antileishmanial, 390 Antimicrobial, 388, 390 Antioxidants, 149, 166, 170-172, 190, 207,

Uses of plant food residues as sources for phytochemical extracts

Examples of the actual use of wastes from fruit processing industries to produce extracts that are available in the market include orange, grape, apple and olive residues. The residues from orange-juice extraction industries (orange albedo and flavedo, and fruit segments) have already been exploited for many years for the extraction of flavanones (hesperidin and related compounds) and pectin. Grape wastes from the wine-making industries (grape pomace and seeds) are also used industrially for the extraction of anthocyanin pigments, procyanidins and polyphenol extracts (Gabrielska et al., 1997 Lu and Foo, 1999). From the olive-oil extraction industries the residues can also be used for extraction of hydroxytyrosol (Visioli et al., 1999), the main phenolic antioxidant in olive oil, an efficient process for this purpose, has been patented and exploited industrially (Fernandez-Bolanos et al., 2002). From the cider industries, the apple pomaces are already used for extraction of pectins...

Stratospheric ozone depletion

Stratospheric ozone is thought to have begun forming several billion years ago as a result of the solar-powered destruction and recombination of oxygen. The natural concentration of stratospheric ozone is now maintained through the dynamic equilibrium existing between the production and destruction of ozone. The destruction is catalysed by trace amounts of hydrogen, nitrogen and halogen free radicals (especially chlorine and bromine). These free radicals occur naturally but, in recent decades, their concentration has been increased greatly by industrial activities. This has upset the equilibrium and led to a sustained decline in stratospheric ozone concentrations (2,52).

Tropospheric Ozone And Associated Photochemical Oxidants 871

Appendix I Enthalpies of Formation of Some Gaseous Molecules, Atoms, and Free Radicals at 298 K 943 Appendix II Bond Dissociation Energies 945 Appendix III Running the OZIPR Model 947 Appendix IV Some Relevant Web Sites 949 Appendix V Pressures and Temperatures for Standard

David J Kieber Barrie M Peake and Norman M Scully

The photolysis of organic and inorganic constituents in natural waters is also an important mechanism for the production of free radicals 9 . Zafiriou and Dister 10 determined that the total production rate of radicals varied from 6 to 24 x 10-8 M h_1 during the summer in the Atlantic Ocean along the East Coast of the United States, employing a solar simulator with a spectral output and photon flux approximately equal to the noon time solar irradiance on a clear

Origin and general characterisation of the byproducts 1621 Fruit and vegetable juices

The major solid waste is obtained by pressing of fruits or vegetables and solid-liquid separation. This 'pomace' can contain pulp, peels, seeds and stones. The further utilisation of pomace depends on the fruit or vegetable type. Pomace is generally used for extraction of valuable compounds and for production of foodstuffs. For instance, pectin can be found to a greater or lesser extent in most fruits and is, after extraction and purification (see Section 16.4.1), added as gelling agent in numerous food products (including jams, fillings, sweets, etc.). Pomace can also provide other food additives - such as dietary fibres (see Section 16.3.1), lactic acid, pigments, vinegar, natural sweeteners and cellulose (see Section 16.4.2) (Nawirska and Kwasniewska, 2005). Some tropical fruits contain protein-degrading enzymes (papain in papaya, or bromelain in pineapple) which are used as meat tenderisers or washing powders or used in beer brewing. Pharmaceuticals and phytochemicals are also...

Lipids from natural products

Prospective applications for the SFE of lipids or oils, apart from common vegetable oils (soy oils, corn oil, rice bran oil, sunflower oil, olive oil, etc.), also include animal fats, fish oil, oil from seaweeds and oil from microorganisms like fungi (Walker et al., 1999 Mukhopadhyay, 2000 Shen et al., 1996). Major components of lipids include monoglycerides, diglycerides, triglycerides and free fatty acids (FFAs) minor constituents include sterols, toco-pherols, gums, alkaloids, flavonoids, wax and volatile compounds, which provide taste and odor. Most studies concerning SFE of lipids are focused on the optimization of extraction conditions to increase the yield of extract-able materials (Hu, 1995). Several components of lipids have significant health and nutritional implications for the food and pharmaceutical industries. PUFAs have important therapeutic value (Shahidi and Wanasundara, 1998 Galli and Butrum, 1991). Unsaturated fatty acids and saturated fatty acids have different...

Photochemistry of Important Atmospheric Species

Absorption of sunlight induces photochemistry and generates a variety of free radicals that drive the chemistry of the troposphere as well as the stratosphere. This chapter focuses on the absorption spectra and photochemistry of important atmospheric species. These data can be used in conjunction with the actinic fluxes described in the preceding chapter to estimate rates of photolysis of various molecules as well as the rate of generation of photolysis products, including free radicals, from these photochemical processes.

Key reasons for exploiting plantderived compounds from coproducts

Growing apprehensiveness about the safety of synthetic commercial antioxidants has prompted great efforts to screen active and stable antioxidants obtained from natural sources (Peschel et al, 2006). Until now, most attention has been paid to oral administration of natural radical scavengers as food supplements. However, protection from hazardous species is not only of nutritional relevance. Neither are oxidation reactions an exclusive concern of the food industry. In fact, the customer's awareness of 'non-chemical' ingredients in health products has also to be faced by the cosmetic and pharmaceutical industry. These three sectors are drawn together promoting products named functional foods, food supplements, nutraceuticals and or cosmeceuticals (Schieber et al., 2001).

Metal Accumulation and Homeostasis in Antarctic Molluscs

Metallothioneins are soluble, low-molecular weight, cysteine-rich proteins. Metal ions within cells cause their rapid neosynthesis by enhancing metallothionein gene transcription (Squibb and Cousin 1977). Metalloth-ioneins have been reported not only in molluscs but also in many other Antarctic organisms such as the sea urchin S. neumayeri and several species of fish (e.g. Scudiero et al. 1997 Carginale et al. 1998). The cysteine content in cadmium-induced metallothionein from the digestive gland of A. colbecki (Ponzano et al. 2001) is lower than that in metallothioneins purified from vertebrates and invertebrates in other seas. In addition to metallothioneins, many other biochemical markers can be used as biological indices of exposure to or of the effects of contaminants in molluscs. The enhancement of reactive oxygen species (ROS) has often served as a general pathway of tox-icity induced by pollutants and oxidative stress (Winston 1991). Cells have evolved low-molecular scavengers...

Aerosol Processes In The Stratosphere

Stratospheric trace species include sources, free radicals (species with an unpaired electron), and temporary reservoirs. Source species are produced at Earth's surface and are stable enough to eventually reach the stratosphere. Temporary reservoirs are generated in the stratosphere, but they are ultimately transported downwards into the troposphere, where they are rapidly removed by rainout or washout. Both sets of species decompose in the stratosphere producing free radicals either by photolysis or by reaction with another radical. Free radicals can participate in ozone destruction cycles but can also react with each other to produce stable reservoirs. Thus photochemistry is a source of radicals, while gas-phase reactions interconvert radicals into different forms or else destroy free radicals by producing stable reservoirs. Practically all gas-phase chemical reactions involve free radicals reactions in the gas phase between nonradical (saturated) species are usually too slow to...

Factors controlling UV injury

In aquatic habitats UV can interact additively or synergistically with certain contaminants, increasing their toxicity and severity of injury ( 81 , see Chapter 7). Chemicals of anthropogenic origin that have molecular characteristics similar to photoprotective substances may be altered by absorbed UV. This interaction may generate free radicals or singlet oxygen that can alter DNA, enzymes, or lipoproteins leading to cellular injury and rapid death. For example, polycyclic aromatic hydrocarbons (PAHs) and other components of crude and refined petroleum increase in toxicity by as much as 10000-fold in the presence of UV 82 . Unexpected acute mortality occurred among bluegill sunfish treated with the PAH anthracene and exposed to solar UV in outdoor artificial streams 83 . It was concluded that solar UV significantly enhanced the toxicity of anthracene to the fish. In a subsequent study with juvenile sunfish (Lepomis spp.), the acute toxicity of anthracene was photoenhanced by...

Subcategory 3 Solution Crumb Rubber Production

The rubber cement is then sent to storage tanks where antioxidants and extenders are mixed in. The rubber cement is pumped from the storage tank to the coagulator where the rubber is precipitated with hot water under violent agitation. The solvent and unreacted monomer are first steam stripped overhead and then condensed, decanted, and recycled to the feed stage. The bottom water layer is discharged to the wastewater treatment facility.

Important sources of highvalue coproducts 1751 Fruit processing

Grape pomace (from the wine and must industries) amounts to more than 9 million tons per year (Schieber et al., 2001). A great range of products such as ethanol, tartrates, citric acid, grape seed oil, hydrocolloids and dietary fibre are recovered from grape pomace. Polyphenol extracts are also produced and commercialised from residues. Anthocyanins, catechins, flavonol glycosides, and phenolic acids are the principal phenolic constituents of grape pomace. The content of the stilbenoid resveratrol, although small, is relevant as the price of the extracts often depends on the content of this minor constituent due to its demand and biological activity. Grape seed extracts rich in procyanidins with different degrees of polymerisation are traded, as well as fibre with antioxidant activity due to its polyphenols and white grape skin extracts rich in flavonols in addition to procyanidins. The use of citrus by-products is a traditional industry and was reviewed 10 years ago by Braddock...

Ecological Sensitivity Of Woody Plants To Oceanic Conditions

Fig. 9.17 Bog rosemary (Andromeda polifolia), an inhabitant of cold north temperate bogs which can store 75 of its fixed carbon below ground (see Chapter 3). Bog rosemary has also been found to have high antioxidant activity and high total phenolic content (Kahkonen et al, 1999). Fig. 9.17 Bog rosemary (Andromeda polifolia), an inhabitant of cold north temperate bogs which can store 75 of its fixed carbon below ground (see Chapter 3). Bog rosemary has also been found to have high antioxidant activity and high total phenolic content (Kahkonen et al, 1999).

Origin and occurrence of NDMA in food drinks and cigarette smoke

In vitro experiments frequently use excessively high nitrite concentrations, making extrapolation to realistic physiological concentrations complicated. Investigation of the endogenous NDMA formation in vivo is particularly difficult due to its rapid metabolism. Furthermore, coingestion of foods rich in some antioxidants, such as strawberries, garlic, and green tea, significantly inhibit nitrosation under gastric conditions 56,57 . For example, human excretion of NDMA was 26 times lower following green tea ingestion. These factors make predicting endogenous formation of NDMA in humans difficult, and we will not address it further herein.

Introduction consumer interests as a key driver to improve waste management in food processing

More than 10 million tonnes of food processing waste are produced within the European Community every year. The costs associated with handling the waste produced within the food industry constitute many tens of millions of euros, attributable to landfill costs and other waste disposal routes. However, this waste is also known to contain significant amounts of valuable components which remain unexploited as a result of current food-waste processing practices. There are many kinds of potentially valuable components in these wastes nutrients and micronutrients (protein, dietary fibre, prebiotics, antioxidants and other bioactive polyphenolics), rheologi-cal agents (hydrocolloids, gelling agents, films and coatings), texturised residues, flavours and colourants (juices) (Cheunk et al., 2003). These could be utilised in pharmaceutical, cosmetic and nutraceutical high-value products, as well as in contributing to medium-value food and feed ingredients. In the following we will focus on...

Flooding And Unflooding

Initiating membrane damage leading to the destruction of cell organelles. Peroxidation products, such as ethane and malonedialdehyde, appear rapidly in the organs and tissues of non-tolerant plants (Braendle & Crawford, 1999). The inner membrane system of mitochondria seems to be particularly sensitive. The production of ROS is a common feature also for other stresses, including drought, salt injury, and pollution damage. Plants that are able to survive prolonged oxygen deprivation followed by a return to air all have the capacity to withstand both prolonged anoxia and avoid post-anoxic injury to their cell membranes with a protective antioxidant system (Braendle & Crawford, 1999). The highly anoxia-tolerant Acorus calamus (see below) maintains high concentrations of antioxidants, including ascorbate, phenolics and glutathione, throughout the period in which the plant is under anoxia, as well as the enzymes ascorbate reductase, peroxidase and catalase. Iris pseudacorus has a tolerance...

Nutritional Quality

Evidence indicates that secondary plant metabolites play critical roles in human health and may be nutritionally important (Brandt and M0lgaard 2001). Some scientists believe that plant-based phenolic metabolites are very important due to their antioxidant activity (Rein et al. 2000 Asami et al. 2003), while others have found that other bioactive secondary metabolites, such as glucosinolates from broccoli, are more likely to account for the health-promoting effects of vegetables and fruits (Brandt et al. 2004). Secondary metabolites are common constituents of fruits and vegetables that function in the defence against disease, insect and animal herbivory (Stevenson et al. 1993). There is a growing concern that the levels of some secondary metabolites may be lower than optimal for human health in foods grown in conventional agricultural practices (Brandt and M0lgaard 2001). This concern arises because conventional agricultural practices utilize levels of plant nutrients that can result...

Chemical removal

The Earth's atmosphere is oxidizing in nature (Ravishankara, 1988) and therefore CH4 will be photo-oxidized via reaction with free radicals and possibly some closed-shell species in the atmosphere. There are a number of potential species in the atmosphere that may initiate this photo-oxidation, but it emerges that very few of these are important sinks for CH4. Although the dissociation energy for a C-H bond in CH4 is 4.55 eV ( 440 kJ mol), which equates to a wavelength of 272.2 nm, there are no electronic states of CH4 in this region of the spectrum (Yung and DeMore, 1999). Consequently, CH4 can only be broken down by high-energy radiation (100-140 nm) and this is found in the mesosphere (equivalent to an altitude of 50-80 km) and upper regions of the atmosphere. Whilst direct photolysis of CH4 is important in the atmospheres of Jupiter, Saturn, Uranus and Neptune, it is

Biolive

For use as fertilizer Ultrahydrophytosqualene New Processes for the Generation of Squalene by Supercritical Fluid Extraction from Waste of Olive Oil Production and Hydrogenation of Squalene Improvements of Treatments and Validation of the Liquid-Solid Waste from the Two-Phase Olive Oil Extraction Natural Antioxidants from Olive Oil

DNA Damage

These measurements quantify net dimer levels, and an increased rate of dimer formation might possibly have been countered by enhanced repair capability. Xu et al. (2008a) also noted that the rate of oxidant production appeared to be increased in these same soybean lines in ambient compared to reduced UV-B levels, but observed an increase in the antioxidant system in the magenta soybean line. It is well-known that the balance of repair mechanisms vs. those that provide protection is important (Jansen et al., 1998 Frohnmeyer and Staiger, 2003), and that an increase in UV-absorbing compounds is a common response to UV-B radiation (Searles et al. 2001). However, the results of this study do not allow us to quantify if it was protection (in the case of Clark) and repair (in the case of Clark-magenta) that maintained the low levels of CPDs. Clearly, the effects of UV-A on plant metabolism and the interactions between PAR, UV-A, and UV-B, is not fully understood. This is an area in which...

Concluding remarks

Finally, information on the induction and removal of lesions other than CPDs is urgently needed. Very little is known on the induction of the 6-4 PP in aquatic organisms, let alone the Dewar photoproduct. Furthermore, other lesions that may be induced by both UV-B and UV-A may be highly relevant. It is well known that UV-A may cause more than half of the total UVR effect, reducing primary and secondary production, both in marine and fresh water systems. It remains to be investigated whether or not the UV-A effect can be attributed to damage to photosystems alone (for phototrophs), or that other forms of oxidative damage are also important. The various pathways for ameliorating oxidative stress, such as the presence or induction of antioxidants, may be highly relevant as well.

Phenols

Olives and olive oil contain phenolic compounds (Tsimidou et al., 1992 Tsimidou, 1998) that, in vitro, have been shown to exert potent biological activities including but not limited to antioxidant actions (Visioli et al., 1998). Visioli et al. (1999) reported that OMWW extracts contain potent antioxidants. Among these polyphenols, hydroxytyrosol has been revealed to be the most interesting because of its remarkable pharmacological and antioxidant properties. Hydroxytyrosol originates in all likelihood from the hydrolysis of oleuropein by means of an esterase during the mill process. Chikamatsu et al. (1996) found that hydroxytyrosol inhibits the formation of melanin and lipid peroxides and they patented its use in topical and bath preparations. Because hydroxytyrosol is commercially unavailable, chro-matographic methods of purification from OMWW, virgin olive oil, olive leaves and synthetic procedures could allow a natural and non-toxic anti-oxidant to be obtained. Recovery of...

Electron Beam

Transit in matter, an electron loses energy through collisions that ionize atoms and molecules along its path. Bacteria and viruses are destroyed by the secondary ionization products produced by the primary traversing electron. The energetic electrons dissociate water into free radicals H+ and OH . These may combine to form active molecules-hydrogen, peroxides, and ozone. These highly active fragments and molecules attack living structures to promote their oxidation, reduction, dissociation, and degradation. Studies have indicated that 400,000 rads would be adequate for sewage disinfection. At 100 ergs per gram rad, 400,000 rads would raise the temperature of the water or sludge by 1 C. At this dose, each cm2 of moving sludge would receive about 12 x 1012 electrons, each electron producing some 30,000 secondary ionizations.

Quenching mechanisms

Exposure to UVR is known to result in a variety of negative effects however, the interaction of UVR with photosensitizing molecules, some organic molecules and oxygen results in the production of toxic photoproducts including reactive oxygen species (ROS) both intracellular and in the external environment. Toxic photoproducts have the ability to cause more damage than the UVR exposure itself. Toxic photoproducts are neutralized by various agents including antioxidants such as ascorbate, quenchers such as carotenoids and various scavenging enzymes, the levels of which are up-regulated by the presence of UVR 123-125 . Exposure to UVR can result in an increase in the production of photoreactive species on the one hand and, on the other hand, result in the induction of enzymes to neutralize these species. 10.3.1 Antioxidants Antioxidants, quenching molecules or radical scavenging enzymes such as superoxide dismutase (SOD), ascorbate peroxidase and catalase react with and neutralize the...

Wounding

The level of phenolic compounds varies greatly among fruits and vegetables, within their various tissues and over time. Young fruit have higher levels of phenolic compounds than ripe fruit, while younger vegetative tissue has lower levels than more mature tissue. Artichokes, apples and potatoes, for example, have relatively high levels of phenolic compounds constitutively, and rapidly brown when cut. In contrast, lettuce has low levels of phenolic compounds and the synthesis and accumulation of wound-induced phenolic compounds significantly increase the development of tissue browning. Development of strategies to control tissue browning must therefore be tailored to the requirements of the specific commodity and form in which it is marketed (e.g. whole or fresh-cut). Antioxidants can lessen the browning of phenolic compounds already present in the tissue, while interfering with phenolic synthesis can prevent the accumulation of

New products

The first new products obtainable from oil wastes are isoflavones, which are extracted from the waste of soy protein production. Isoflavones are structurally close to oestrogens and have been proved to aid in the fight against breast and prostate cancer. Another product is tocotrienol, which is a strong antioxidant, like vitamin E, that is extracted from palm oil processing by-products. From the palm oil waste stream there is also the possibility of extracting a natural P-carotene. Additional soy oil by-products in preparation are phosphytidyl choline and phosphytidyl serine. These products have health benefits and can be sold into the neutraceutical market.

Chemical Processes

Oxidation rate arising from hydroxyl radicals OH These free radicals are generated from added oxidants and are characterized by high reactivity, low selectivity towards organic compounds and high oxidation potential (E 2.80 V) 57 . Generally, advanced oxidation processes may be divided into two groups chemical oxidation (without photolysis) and photochemical (enhanced by photolysis).

Cleaning

Requirements, many types of cleaning processes have been developed. However, considering the basic character of the cleaning solution, four main cleaning groups can be defined solvent cleaning, alkaline cleaning, electrocleaning, and acid cleaning. Solvent cleaning is described under solvent degreasing. Alkaline cleaning involves the use of builders such as sodium or potassium salts of phosphates, carbonates, silicates and hydroxides, surfactants, and, sometimes, antioxidants or inhibitors, complex formers, stabilizers, and small amount of solvents. Newly introduced nonemulsifying surfactants are very effective in separating the soil from surfaces. Strong alkaline cleaners may also contain cyanide. Alkaline cleaning is more effective for removing soil from surfaces.

ISCO Process

ISCO is a technology in which an oxidant, and other amendments as necessary, is introduced into contaminated media to react with site contaminants such as MTBE, other fuel oxygenates, and other organic compounds, converting them to innocuous products, such as carbon dioxide and water. Typically, hydrogen peroxide (H ), ozone (O3), or permanganate (MnO-) oxidants have been used to treat MTBE in soil and groundwater. Persulfate (S2O-) compounds have also been used as chemical oxidants for treating MTBE. All of these chemicals react, either directly or through the generation of highly reactive free radicals, such as OH and H , or SO- , with organic compounds such as MTBE to break hydrocarbon bonds and form degradation products such as alcohols, carbon dioxide, and water. In some applications, different oxidants may be used in combination, such as H2O2 O3, or in conjunction with catalysts, such as H2O2 in the presence of ferrous iron (Fenton's chemistry or reagent), to enhance oxidation...

Diseases

Chronic diseases such as Alzheimer's, emphysema, heart disease, acquired immune deficiency syndrome (AIDS), and cancer are diseases that have a slow onset and last for extended periods of time. Diseases can also be classified by type, such as infectious, developmental, nutritional, radiation, and chemical. Many diseases, such as neoplastic diseases like cancer, involve both genetic components and environmental factors leading to increases in susceptibility. Thermal, chemical, and radiation damage mainly results from a damaging excess of kinetic energy or ionization of molecules in tissues leading to cell death. Free radicals react with molecules in the cell and change their structure, affecting their ability to function. This is the basis for Paul

Grape and wine

The majority of the solid wastes are produced during the first steps of the processing of the grapes. Grapes are harvested and crushed, resulting in mash and stems (2-8 of processed material). The mash is then pressed and separated into juice and pomace (10-20 ). Stems and pomace are the principal by-products of wine production and are the source of valuable components (ethanol (see Section 16.5.4), tartrate, citric acid (see Section 16.5.5), hydrocolloids (see Section 16.4), dietary fibres (see Section 16.3.1)) (Schieber et al., 2001). High-value antioxidants can be extracted from stems - such as resveratrol used in nutraceuticals, cosmetics or biopharmaceuti-cals. Pomace also contains other antioxidants (procyanidins, polyphenol extracts) and pigments (anthocyanin) (Tomas-Barberan et al., 2004) and can be used for production of grape seed oil.