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Antioxidants EDTA,

Certain compounds, known as chelating agents (qv), react synergisticaHy with many antioxidants. It is beheved that these compounds improve the functional abiUties of antioxidants by complexing the metal ions that often initiate free-radical formation. Citric acid and ethylenediaminetetraacetic acid [60-00-4] (EDTA), C2QH2gN20g, are the most common chelating agents used (22). [Pg.437]

The rate of peroxide decomposition and the resultant rate of oxidation are markedly increased by the presence of ions of metals such as iron, copper, manganese, and cobalt [13]. This catalytic decomposition is based on a redox mechanism, as in Figure 15.2. Consequently, it is important to control and limit the amounts of metal impurities in raw rubber. The influence of antioxidants against these rubber poisons depends at least partially on a complex formation (chelation) of the damaging ion. In favor of this theory is the fact that simple chelating agents that have no aging-protective activity, like ethylene diamine tetracetic acid (EDTA), act as copper protectors. [Pg.466]

There are some differences in the regulation of US and EU antioxidants. The restrictions on synthetic antioxidants are more strict in the EU, e.g. TBHQ, THBP, anoxomer, ethoxyquin, guaiac resin and derivates of thiodipropionic acid are not permitted there. On the other hand, sulphur dioxide and sulphites, citric and tartaric acids and their salts and salts of EDTA are not listed as permitted antioxidants in the US. [Pg.294]

Secondary antioxidants, i.e., sequestrants or chelators, are important compounds in the prevention of lipid oxidation. The effect of chelators tested varied with the different compounds. Of those chelators tested, ethylenediaminetetraacetic acid (EDTA, tetrasodium salt) and sodium phytate were the most effective inhibitors of lipid oxidation (so indicated by low hexanal and TEARS values) and MFD (as seen by high CBB and low PIT and CBD intensity values), see Table 5. Sodium phytate was previously shown to chelate iron and thus, was proposed as a food antioxidant(7J). Sodium citrate at a concentration of 500... [Pg.65]

Additional particulars should also be noted. First, vacuum when used in combination with EDTA, showed a very large decrease in lipid oxidation when compared to those EDTA-treated samples without vacuum (EVB vs ENB). This was not the case when the primary antioxidant, PG, was used with or without vacuum (EVA vs ENA). In this latter case, PG was effective with or without vacuum, although there were some intensity differences observed and by combining with vacuum, MFD and lipid oxidation was decreased. Next, vacuum alone lowered lipid oxidation (EVO vs ENO). Finally, by combining vacuum with EDTA a strong synergistic effect was observed. [Pg.69]

Thus, antioxidant effects of nitrite in cured meats appear to be due to the formation of NO. Kanner et al. (1991) also demonstrated antioxidant effects of NO in systems where reactive hydroxyl radicals ( OH) are produced by the iron-catalyzed decomposition of hydrogen peroxide (Fenton reaction). Hydroxyl radical formation was measured as the rate of benzoate hydtoxylation to salicylic acid. Benzoate hydtoxylation catalyzed by cysteine-Fe +, ascorbate - EDTA-Fe, or Fe was significantly decreased by flushing of the reaction mixture with NO. They proposed that NO liganded to ferrous complexes reacted with H2O2 to form nitrous acid, hydroxyl ion, and ferric iron complexes, preventing generation of hydroxyl radicals. [Pg.269]

Sodium metabisulfite is an antioxidant agent widely used in pharmaceutical preparations to reduce or prevent oxidation. There are some studies, however, that have shown that metabisulfite, under specific conditions, may have indirect oxidant properties. Baker et al. [37] demonstrated that sulfite propofol emulsion, but not EDTA propofol emulsion, underwent chemical changes during a simulated intravenous infusion. Compounds were identified as propofol oxidation products. The increase of propofol oxidation products demonstrated that sulfite from metabisulfite created a strong oxidant environment when air was introduced. Lavoie et al. [38]... [Pg.478]

EDTA Chelates alkaline earth and heavy metals 0.005-0.01% w/v antimicrobial activity synergy Often used in combination with other antimicrobial preservatives, and other antioxidants based on their synergy... [Pg.173]

Seibig S, van Eldik R (1997) Kinetics of F e (11) EDTA oxidation by molecular oxygen revisited. New evidence for a multistep mechanism. Inorg Chem 36 4115-4120 SimandanT, Sun J, DixTA(1998) Oxidation of DNA bases,deoxyribonudeosides and homopolymers by peroxyl radicals. Biochem J 335 233-240 Spinks JWT, Woods RJ (1990) Introduction to radiation chemistry. Wiley, New York Strohmeier Gort A, Imlay JA (1998) Balance between endogeneous superoxide stress and antioxidant defenses. J Bacteriol 180 1402-1410... [Pg.46]

EDTA, Ethylenediaminetetraacetic acid TAS, total antioxidant status TRAP, total peroxyl-radical-trapping antioxidant capability of plasma ABAP, 2,2 -azobis(2-amidopropane) FRAP, ferric-reducing activity of plasma H2-DCF-DA, 2, 7 -dichlorofluorescein diacetate ORAC, oxygen-radical-absorbing capacity ABTS, 2,2 -azinobis(3-ethylbenzthiazoline-6-sulfonic acid). [Pg.242]

EDTA is also used as a synergist to increase the activity of antioxidants, and to complex small amounts of heavy metal ions. EDTA has been frequently used to stabilize preparations of penicillins, ascorbic acid, epinephrine and prednisolone [4], Over the past 35 years, EDTA has been used to induce hypocalcaemia in cows and other species, primarily for the induction of hypocalcaemia as a model for milk fever [8]. [Pg.62]

Metal-chelating agents, such as citric acid and phosphoric acid, act as synergists in conjunction with antioxidants (Badings, 1960). Salts of ethyle-nediaminetetraacetic acid (EDTA) have been shown to inhibit oxidation in this manner (Arrington and Krienke, 1954 King and Dunkley, 1959a). [Pg.573]

The antioxidant activity of dihydropyrimidinones was also evaluated. In one study [32], the compounds were prepared by ultrasound irradiation in the presence of NH4CI in good yields. The antioxidant activities were measured in liver homogenates from male adult albino Winstar rats. The compounds were tested for their activity against Fe- and EDTA-induced lipid peroxidation at various... [Pg.244]

Therefore, PG is widely used in foods where lipid-soluble antioxidants such as BHA, BHT, and TBHQ are not suitable. PG is inappropriate for frying due to its poor stability at high temperatures. It decomposes at its melting point of 148°C (11, 12). Gallates can form undesirable, dark-colored complexes with iron and copper thus, they are sold as a mixture with metal chelators such as EDTA. Gallates also act synergistically with other antioxidants (11, 12). [Pg.536]

There are various synthetic antioxidants, such as butylated hydroxytoluene (BHA), propyl gaUate (PG), ethylenediaminetetraacetic acid (EDTA), etc. that are used in commercial oils TBHQ is known to produce the best results in frying applications. [Pg.2000]

In chronic intoxication, the therapeutic objective is removal of the patient from the site of exposure and elimination of the noxa from the body (e. g. detoxification measures, infusions of calcium-disodium EDTA in cases of lead poisoning, etc.). There is no justification whatsoever for therapeutic nihilism. With the aid of dietetic measures (if necessary) and adjuvant therapy (N-acetylcysteine, antioxidants, ursodeoxycholic acid, S-adenosyl-methionine, etc.), the clinical course and hence the prognosis can be favourably influenced. Insufficient regression or inadequate normalization of laboratory parameters and histological changes despite removal of the patient from the area of exposure must arouse suspicion of a further, still existing noxa (alcohol, medicaments, other chemicals). [Pg.572]


See other pages where Antioxidants EDTA, is mentioned: [Pg.67]    [Pg.67]    [Pg.438]    [Pg.16]    [Pg.119]    [Pg.317]    [Pg.15]    [Pg.281]    [Pg.777]    [Pg.89]    [Pg.267]    [Pg.268]    [Pg.778]    [Pg.302]    [Pg.302]    [Pg.432]    [Pg.558]    [Pg.628]    [Pg.407]    [Pg.205]    [Pg.31]    [Pg.287]    [Pg.109]    [Pg.290]    [Pg.225]    [Pg.234]    [Pg.241]    [Pg.133]    [Pg.438]    [Pg.88]    [Pg.455]    [Pg.367]    [Pg.369]   
See also in sourсe #XX -- [ Pg.133 ]




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