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Thearubigins
Thearubigins are polymeric polyphenols that are formed during the enzymatic oxidation and condensation of two gallocatechins (epigallocatechin and epigallocatechin gallate) with the participation of polyphenol oxidases during the fermentation reactions in black tea. Thearubigins are red in colour and are responsible for much of the staining effect of tea. Therefore, a black (fully oxidized) tea often appears red while a green or white tea has a much clearer appearance. The colour of a black tea, however, is affected by many other factors as well, such as the amount of theaflavins, another oxidized form of polyphenols. Thearubigins were first studied by Roberts, E. A. H. in the 1960s by the means of spectroscopy or by fractionation or paper chromatography. They have been identified as proanthocyanidins in 1969. The thearubigins formation has been studied in an in vitro model in 1983. Thearubigins from black tea extracts have been studied by degradation in 1996. Quantification meth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theaflavin
Theaflavin (TF) and its derivatives, known collectively as ''theaflavins'', are antioxidant polyphenols in tea, polyphenols that are formed from the condensation of flavan-3-ols in tea leaves during the enzymatic oxidation (sometimes erroneously referred to as Fermentation (tea), fermentation) of black tea. Theaflavin-3-gallate, theaflavin-3'-gallate, and Theaflavin digallate, theaflavin-3-3'-digallate are the main theaflavins. Theaflavins are types of thearubigins, and are therefore reddish in color. See also * Theaflavin 3-gallate References {{Teas Phenol antioxidants Cancer research Antiviral drugs Thearubigins Catechols Resorcinols Tropolones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopy
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Current applications of spectroscopy include biomedical spectroscopy in the areas of tissue analysis and medical imaging. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theasinensin B
Theasinensin B is polyphenol flavonoid from black tea ('' Thea sinensis''). See also * Theasinensin A Theasinensin A is polyphenol flavonoid from black tea (''Camellia sinensis'') created during fermentation, by oxidation of epigallocatechin gallate. Its atropisomer is theasinensin D. See also *Theasinensin B *Theasinensin C *Theasinensin D *Th ... * Theasinensin C References * Flavanols Polyphenols Biphenyls {{Ether-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theasinensin A
Theasinensin A is polyphenol flavonoid from black tea (''Camellia sinensis'') created during fermentation, by oxidation of epigallocatechin gallate. Its atropisomer is theasinensin D. See also *Theasinensin B *Theasinensin C *Theasinensin D *Theasinensin E *Theasinensin F *Theasinensin G References * * * Flavanols Polyphenols Biphenyls {{Ether-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proanthocyanidin
Proanthocyanidins are a class of polyphenols found in many plants, such as cranberry, blueberry, and grape seeds. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex polyphenols, having the same polymeric building block, form the group of Condensed tannin, condensed tannins. Proanthocyanidins were discovered in 1947 by Jacques Masquelier, who developed and patented techniques for the extraction of oligomeric proanthocyanidins from pine bark and grape seeds. Proanthocyanidins are under preliminary research for the potential to reduce the risk of urinary tract infections (UTIs) by consuming cranberries, grape seeds or red wine. Distribution in plants Proanthocyanidins, including the lesser bioactive and bioavailable polymers (four or more catechins), represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins. They can be found in many plants, most notably ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Chromatography
Paper chromatography is an analytical method used to separate colored chemicals or substances. It can also be used for colorless chemicals that can be located by a stain or other visualisation method after separation. It is now primarily used as a teaching tool, having been replaced in the laboratory by other chromatography methods such as thin-layer chromatography (TLC). This analytic method has three components, a mobile phase, stationary phase and a support medium (the paper). The mobile phase is generally a non-polar organic solvent in which the sample is dissolved. The stationary phase consists of (polar) water molecules that were incorporated into the paper when it was manufactured. The mobile phase travels up the stationary phase by capillary action, carrying the sample with it. The difference between TLC and paper chromatography is that the stationary phase in TLC is a layer of adsorbent (usually silica gel, or aluminium oxide), and the stationary phase in paper chromato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fractionation
Fractionation is a separation process in which a certain quantity of a mixture (of gasses, solids, liquids, enzymes, or isotopes, or a suspension) is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques. Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gasses are separated by fractional distillation by difference in boiling point. Fractionation of components also takes place in column chromatography by a difference in affinity between statio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolic Content In Tea
The phenolic content in tea refers to the phenols and polyphenols, natural plant compounds which are found in tea. These chemical compounds affect the flavor and mouthfeel of tea. Polyphenols in tea include catechins, theaflavins, tannins, and flavonoids. Polyphenols found in green tea include, but are not limited to, epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin; flavanols such as kaempferol, quercetin, and myricitin are also found in green tea. Catechins Catechins include epigallocatechin-3-gallate (EGCG), epicatechin (EC), epicatechin-3-gallate (ECg), epigallocatechin (EGC), catechin, and gallocatechin (GC). The content of EGCG is higher in green tea. Catechins constitute about 25% of the dry mass of a fresh tea leaf, although total catechin content varies widely depending on species, clonal variation, growing location, season, light variation, and altitude. They are present in nearly all teas made from '' Camelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stain
A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make materials appear used, degraded or Cleanliness, permanently unclean. Intentional staining is used in biochemical research, and for artistic effect, such as in wood staining, weathering steel, rust staining and stained glass. Types There can be intentional stains (such as wood stains or paint), indicative stains (such as food coloring dye, and staining, the use of one or more substances to enhance visibility of samples in a microscope or other imaging device. Numerous naturally-occurring stains exist, such as rust on iron and a patina on bronze, as do accidental stains such as from ketchup and oil on fabrics and other materials. Different types of material can be stained by different substances, and stain resistance is an important characteristic in mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Tea
Black tea (also literally translated as red tea from various East Asian languages) is a type of tea that is more tea processing, oxidized than oolong, yellow tea, yellow, white tea, white, and green tea, green teas. Black tea is generally stronger in flavour than other teas. All five types are made from leaves of the shrub (or small tree) ''Camellia sinensis,'' though ''Camellia taliensis'' is also rarely used. Two principal varieties of the species are used – the small-leaved Chinese variety plant (''C. sinensis'' var. ''sinensis''), used for most other types of teas, and the large-leaved Assamese plant (''C. sinensis'' var. ''assamica''), which was traditionally mainly used for black tea, although in recent years some green and white teas have been produced. First originating in China, the beverage's name there is ''hong cha'' (, "red tea") due to the colour of the oxidized leaves when processed appropriately. Today, the drink is widespread throughout East Asi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
