enin on:
[Wikipedia]
[Google]
[Amazon]
Oenin is an
Oenin is an anthocyanin
Anthocyanins (), also called anthocyans, are solubility, water-soluble vacuole, vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compou ...
. It is the 3-''O''-glucoside
A glucoside is a glycoside that is chemically 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.
Th ...
of 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 ...
(malvidin-3-O-glucoside). It is one of the red pigments found in purple 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 approximately 8,0 ...
skins and red wine
Red wine is a type of wine made from dark-colored grape varieties - (red grapes.) The color of the wine can range from intense violet, typical of young wines, through to brick red for mature wines and brown for older red wines. The juice fro ...
.
Color stabilization of oenin 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
Procyanidin C2 is a B type proanthocyanidin trimer (chemistry), 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 ''Be ...
, 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.
Oenin 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
Phenolic compounds— natural phenol and polyphenols—occur naturally in wine. These include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, sti ...
* 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 tastevi ...
* Malvidin glucoside-ethyl-catechin
* Anthocyanone A, a degradation product of oenin found in wine
References
{{Anthocyanins O-methylated anthocyanins