To the phenols (Polyphenols) group of water-soluble vegetable dyes with over 6,500 different types. They are contained in the fruits, flowers and leaves of plants. The flavonoids were discovered in the 1930s by Nobel Prize winner Albert von Szent-Györgyi Nagyrapolt (1893-1986) and initially as Vitamin P designated. The name is derived from the Latin flavus (yellow) because flavonoids are often, but not always, yellow in color. Most flavonoids are sugar-related glucose or rhamnose, which is then bound as glycosides be designated. The flavonoids are divided into the seven groups anthocyanidins (anthocyanins), flavones, flavonols, flavanols, flavanones, flavanonols and isoflavones.
Occurring species in grapes are for example the group of anthocyanins ( cyanidin Delphinidine malvidine. peonidin, Petunidine), catechin and fisetin in dark (blue to black) grapes, as well quercetin in light (white) grapes. Many flavonoids have a positive effect because a large part is not absorbed and reaches the large intestine. Due to their antioxidative properties, they work in a variety of ways healthy with inflammation, Histamine allergy and cramps, as well as inhibiting against cancer cells and viruses. The second large group of plant dyes found in grapes are carotenoids (for yellow, green, pink, red).