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Trolox Equivalent Antioxidant Capacity
The Trolox equivalent antioxidant capacity (TEAC) assay measures the antioxidant capacity of a given substance, as compared to the standard, Trolox. Most commonly, antioxidant capacity is measured using the ABTS Decolorization Assay. Other antioxidant capacity assays which use Trolox as a standard include the diphenylpicrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC ORAC or Orac may refer to: * Oxygen radical absorbance capacity, a scalar value derived in the laboratory for comparing the antioxidant content of different foods or nutritional supplements * Office of the Registrar of Aboriginal Corporations, for ...) and ferric reducing ability of plasma ( FRAP) assays. The TEAC assay is often used to measure the antioxidant capacity of foods, beverages and nutritional supplements. References Biochemistry detection reactions {{biochem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antioxidant
Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricants, to prevent oxidation, and to foods to prevent spoilage, in particular the rancidification of oils and fats. In cells, antioxidants such as glutathione, mycothiol or bacillithiol, and enzyme systems like superoxide dismutase, can prevent damage from oxidative stress. The only dietary antioxidants are vitamins A, C, and E, but the term ''antioxidant'' has also been applied to numerous other dietary compounds that only have antioxidant properties in vitro, with little evidence for antioxidant properties in vivo. Dietary supplements marketed as antioxidants have not been shown to maintain health or prevent disease in humans. History As part of their adaptation from marine life, terrestrial plants began producing non-marine antioxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trolox
Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) is a water-soluble analog of vitamin E sold by Hoffman-LaRoche. It is an antioxidant like vitamin E and it is used in biological or biochemical applications to reduce oxidative stress or damage. Trolox equivalent antioxidant capacity (TEAC) is a measurement of antioxidant strength based on Trolox, measured in units called Trolox Equivalents (TE), e.g. micromolTE/100 g. Due to the difficulties in measuring individual antioxidant components of a complex mixture (such as blueberries or tomatoes), Trolox equivalency is used as a benchmark for the antioxidant capacity of such a mixture. Trolox equivalency is most often measured using the ABTS decolorization assay. The TEAC assay is used to measure antioxidant capacity of foods, beverages and supplements. Ferric reducing ability of plasma (FRAP) is an antioxidant capacity assays which uses Trolox as a standard. Oxygen radical absorbance capacity (ORAC) used to be an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABTS
In biochemistry, ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) is a chemical compound used to observe the reaction kinetics of specific enzymes. A common use for it is in the enzyme-linked immunosorbent assay (ELISA) to detect the binding of molecules to each other. It is commonly used as a substrate with hydrogen peroxide for a peroxidase enzyme (such as horseradish peroxidase) or alone with blue multicopper oxidase enzymes (such as laccase or bilirubin oxidase). Its use allows the reaction kinetics of peroxidases themselves to be followed. In this way it also can be used to indirectly follow the reaction kinetics of any hydrogen peroxide-producing enzyme, or to simply quantify the amount of hydrogen peroxide in a sample. The formal reduction potentials for ABTS are high enough for it to act as an electron donor for the reduction of oxo species such as molecular oxygen and hydrogen peroxide, particularly at the less-extreme pH values encountered in biologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DPPH
DPPH is a common abbreviation for the organic chemical compound 2,2-diphenyl-1-picrylhydrazyl. It is a dark-colored crystalline powder composed of stable free radical molecules. DPPH has two major applications, both in laboratory research: one is a monitor of chemical reactions involving radicals, most notably it is a common antioxidant assay, and another is a standard of the position and intensity of electron paramagnetic resonance signals. Properties and applications DPPH has several crystalline forms which differ by the lattice symmetry and melting point. The commercial powder is a mixture of phases which melts at ~130 °C. DPPH-I (m.p. 106 °C) is orthorhombic, DPPH-II (m.p. 137 °C) is amorphous and DPPH-III (m.p. 128–129 °C) is triclinic. DPPH is a well-known radical and a trap ("scavenger") for other radicals. Therefore, rate reduction of a chemical reaction upon addition of DPPH is used as an indicator of the radical nature of that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen Radical Absorbance Capacity
Oxygen radical absorbance capacity (ORAC) was a method of measuring antioxidant capacities in biological samples ''in vitro''. Because no physiological proof ''in vivo'' existed in support of the free-radical theory or that ORAC provided information relevant to biological antioxidant potential, it was withdrawn in 2012. Various foods were tested using this method, with certain spices, berries and legumes rated highly in extensive tables once published by the United States Department of Agriculture (USDA). Alternative measurements include the Folin-Ciocalteu reagent, and the Trolox equivalent antioxidant capacity assay. Method The assay measures the oxidative degradation of the fluorescent molecule (either beta-phycoerythrin or fluorescein) after being mixed with free radical generators such as azo-initiator compounds. Azo-initiators are considered to produce the peroxyl radical by heating, which damages the fluorescent molecule, resulting in the loss of fluorescence. Antioxidant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric Reducing Ability Of Plasma
Ferric reducing ability of plasma (FRAP, also ''Ferric ion reducing antioxidant power'') is an antioxidant capacity assay that uses Trolox as a standard. The FRAP assay was first performed by Iris Benzie and J. J. Strain of the Human Nutrition Research Group at the University of Ulster, Coleraine. The method is based on the formation of O-Phenanthroline-Fe(2+) complex and its disruption in the presence of chelating agents. This assay is often used to measure the antioxidant capacity of foods, beverages and nutritional supplements containing polyphenol Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of ...s. Experimental procedure A reaction mixture containing 1 ml of 0.05% O-Phenanthroline in methanol, 2 ml ferric chloride (200 M) and 2 ml of various concentrations ranging from 10 to 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
