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Oenin
Oenin is an anthocyanin. It is the 3-glucoside of malvidin. It is one of the red pigments found in the skin of purple grapes and in wine. Color stabilization of malvidin 3-glucoside at a higher pH can be explained by self-aggregation of the flavylium cation and copigmentation with the Z-chalcone form. In the presence of procyanidin C2, the red color of oenin appears more stable. However, the HPLC chromatogram shows a decrease in the amplitude of the peaks of oenin and procyanidin C2. Concomitantly, a new peak appears with a maximal absorption in the red region. This newly formed pigment probably comes from the condensation of oenin and procyanidin C2. Malvidin 3-glucoside alone is not oxidized in the presence of grape polyphenol oxidase, whereas it is degraded in the presence of a crude grape PPO extract and of caftaric acid forming anthocyanidin-caftaric acid adducts. See also * Phenolic compounds in wine * Wine color * Malvidin glucoside-ethyl-catechin Malvidin glucoside-et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malvidin
Malvidin is an O-methylated anthocyanidin, the 3',5'-methoxy derivative of delphinidin. As a primary plant pigment, its glycosides are highly abundant in nature. Natural occurrences Malvidin is responsible for the blue color found in petals of the ''Primula'' plants of the ''polyanthus'' group. Blue flowers of the blue pimpernel ('' Anagallis monelli'') have also a higher concentration of malvidin. It is responsible primarily for the color of red wine, ''Vitis vinifera'' being one of its sources. It is also present in other berries, such as blueberries (''Vaccinium corymbosum'') or the saskatoon berries (''Amelanchier alnifolia''). Chemistry Slightly acidic and neutral solutions of malvidin are characteristically of a red color, while basic solutions of malvidin yield a blue color. The breakdown of malvidin releases syringic acid. Use as a marker in archaeology The breakdown of malvidin releases syringic acid as revealed in the examination of jars containing shedeh, a dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthocyanin
Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical compound that gives flowers a blue color for the first time in his treatise "''Die Farben der Blüthen''". Food plants rich in anthocyanins include the blueberry, raspberry, black rice, and black soybean, among many others that are red, blue, purple, or black. Some of the colors of autumn leaves are derived from anthocyanins. Anthocyanins belong to a parent class of molecules called flavonoids synthesized via the phenylpropanoid pathway. They occur in all tissues of higher plants, including leaves, stems, roots, flowers, and fruits. Anthocyanins are derived from anthocyanidins by adding sugars. They are odorless and moderately astringent. Although approved as food and beverage colorant in the European Union, anthocyanins are not approved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucoside
A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was originally given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound (exceptions are Jinigrin and Jalapin or Scammonin). It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, and also the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso-dulcite; these may be termed pentosides. Much attention has been given to the non-sugar parts (aglyca) of the molecules; the constitutions of many have been determined, and the compounds synthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grape
A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began perhaps 8,000 years ago, and the fruit has been used as human food over history. Eaten fresh or in dried form (as raisins, currants and sultanas), grapes also hold cultural significance in many parts of the world, particularly for their role in winemaking. Other grape-derived products include various types of jam, juice, vinegar and oil. History The Middle East is generally described as the homeland of grape and the cultivation of this plant began there 6,000–8,000 years ago. Yeast, one of the earliest domesticated microorganisms, occurs naturally on the skins of grapes, leading to the discovery of alcoholic drinks such as wine. The earliest archeological evidence for a dominant position of wine-making in human culture dates from 8,000 years ago in Georg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavylium
Pyrylium is a cation (positive ion) with formula , consisting of a six-membered ring of five carbon atoms, each with one hydrogen atom, and one positively charged oxygen atom. The bonds in the ring are conjugated as in benzene, giving it an aromatic character. In particular, because of the positive charge, the oxygen atom is trivalent. Pyrilium is a mono-cyclic and heterocyclic compound, one of the oxonium ions. Salts Pyrylium and its derivatives form stable salts with a variety of anions. Derivatives Many important cations are formally derived from pyrylium by substitution of various functional groups for some or all the hydrogens in the ring. The 2,4,6-triphenylpyrilium, referred to as the Katritzky salt, (after Alan R. Katritzky) is an important example used in many modern examples of metal catalyzed cross-couplings. Chemical properties Like other oxonium ions, pyrylium is unstable in neutral water. However, pyrylium is much less reactive than ordinary oxonium ions beca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin C2
Procyanidin C2 is a B type proanthocyanidin trimer, a type of condensed tannin. Natural occurrences Procyanidin C2 is found in grape seeds (''Vitis vinifera'') and wine, in barley (''Hordeum vulgare''), malt and beer, in ''Betula spp.'', in ''Pinus radiata'', in '' Potentilla viscosa'', in ''Salix caprea'' or in ''Cryptomeria japonica''. The contents in barley grain of trimeric proanthocyanidins, including procyanidin C2, range from 53 to 151 μg catechin equivalents/g. Possible health uses Proanthocyanidin oligomers, extracted from grape seeds, have been used for the experimental treatment of androgenic alopecia. When applied topically, they promote hair growth ''in vitro'', and induce anagen ''in vivo''. Procyanidin C2 is the subtype of extract most effective. Experiments showed that both procyanidin C2 and Pycnogenol (French maritime pine bark extract) increase TNF-α secretion in a concentration- and time-dependent manner. These results demonstrate that procyanidins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphenol Oxidase
Polyphenol oxidase (PPO; also polyphenol oxidase i, chloroplastic), an enzyme involved in fruit browning, is a tetramer that contains four atoms of copper per molecule. PPO may accept monophenols and/or ''o''-diphenols as substrates. The enzyme works by catalyzing the ''o''-hydroxylation of monophenol molecules in which the benzene ring contains a single hydroxyl substituent to ''o''-diphenols (phenol molecules containing two hydroxyl substituents at the 1, 2 positions, with no carbon between). It can also further catalyse the oxidation of ''o''-diphenols to produce ''o''-quinones. PPO catalyses the rapid polymerization of ''o''-quinones to produce black, brown or red pigments (polyphenols) that cause fruit browning. The amino acid tyrosine contains a single phenolic ring that may be oxidised by the action of PPOs to form ''o''-quinone. Hence, PPOs may also be referred to as tyrosinases. Common foods producing the enzyme include mushrooms (''Agaricus bisporus''), appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caftaric Acid
Caftaric acid is a non-flavonoid phenolic compound. It is found in the juice of grapes (''Vitis vinifera'') and impacts the color of white wine. It is an esterified phenolic acid, composed of caffeic acid, a hydroxycinnamate produced by plants, and tartaric acid, the principal organic acid found in grape berries. As such, caftaric acid is found in all grape juices and wines. During alcoholic and malolactic fermentation, the ester can be enzymatically hydrolysed, releasing the two constituents. Caffeic acid is susceptible to chemical oxidation, and subsequent redox reactions involving caffeic acid can contribute to wine browning over time, and the straw-gold color that can develop in some white wines after bottling. Aside from wine, it is abundantly present in raisins. It also occurs in ''Cichorium intybus'' (common chicory) and is one of the bioactive components of ''Echinacea purpurea'' (Eastern purple coneflower). Caftaric acid has a good bioavailability when fed in rats. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenolic Compounds In Wine
The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers ( proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids. Origin of the phenolic compounds The natural phenols are not evenly distributed within the fruit. Phenolic acids are largely present in the pulp, anthocyanins and stilbenoids in the skin, and other phenols (catechins, proanthocyanidins and flavonols) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine Color
The color of wine is one of the most easily recognizable characteristics of wines. Color is also an element in wine tasting since heavy wines generally have a deeper color. The accessory traditionally used to judge the wine color was the tastevin, a shallow cup allowing one to see the color of the liquid in the dim light of a cellar. The color is an element in the classification of wines. Color origins The color of the wine mainly depends on the color of the drupe of the grape variety. Since pigments are localized in the center of the grape drupe, not in the juice, the color of the wine depends on the method of vinification and the time the must is in contact with those skins, a process called maceration. The Teinturier grape is an exception in that it also has a pigmented pulp. The blending of two or more varieties of grapes can explain the color of certain wines, like the addition of Rubired to intensify redness. Red drupe grapes can produce white wine if they are quickly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
