Grape skin color

Kobayashi S, Goto-Yamamoto N and Hirochika H. 2004. Retrotransposon-induced mutations in grape skin color. Science 304 982. 

Typically, grape skin extract has a specific gravity of 1.13 g/mL at 20°C, a solids content of 28—32° Brix (=t3°), a pH of 3.0, and a color strength as anthocyanin of about 1.25% (as measured at 520 nm ia pH 3.0 citrate buffet). Grape skin extract is also available as spray-dried powders with color values three to four times those of the liquid. The properties and uses of grape skin extract ate similar to those of grape color extract. 

Anthocyanins, grape color extract, grape skin extract E 163 Yes... 

Grape skin extract [COLORANTS FOR FOOD, DRUGS, COSMETICS AND MEDICALDEVICES] (Vol 6) as food additive [FOOD ADDITIVES] (Vol 11)... 

Exempt colors do not have to undergo formal FDA certification requirements, hut are monitored for purity. The colorants exempt from FD C certification are annatto extract, /i-carolene, beet powder, 0-apo—8 -carntenol. canlhaxanthin. caramel, carmine, carrot oil. cochineal extract, cottonseed Hour, ferrous gluconate, fruit juices, grape skin extract, paprika, paprika oleoresin. riboflavin, saffron, titanium dioxide, turmeric, turmeric oleoresin. ultramarine blue, and vegetable juices. See also Colorants (Foods). 

Polymeric color is a term that has been recognized in the wine industries for many years. Condensation of anthocyanins and proanthocyanidins may contribute to the formation of polymeric color, although the structural characterization of the compounds that contribute to polymeric color are poorly defined. Studies using electrospray mass spectrometric analysis demonstrated the presence of pigmented material from grape skins that was chiefiy composed of direct condensation products of anthocyanins extending up to trimers (Vidal et al., 2004). Recent studies have evaluated the effects of processing of blueberries. 

During alcoholic fermentation, the degree of maceration is the first factor that affects the extraction of some compounds present in the grape skin, especially phenolic compounds, which are responsible for the color of the wine. However, not only does the maceration affect the extraction of polyphenols but also of other grape components, such as proteins, polysaccharides and, also, amino acids, which are precursors of biogenic amines. In most red wines, alcoholic fermentation takes place... 

Why emphasize red grape as a superfruit Only red, rather than white or green, is included because its skin color derives from additional phytochemical pigments, mostly anthocyanins, some of which have promise as health agents. Standing tall among these red grape phytochemicals is... 

About the time of the Civil War pink or rose-colored champagnes were fashionable the color being obtained by tinting with a small amount of a dark red wine. Today, a straw color is favored and that is the color of all current commercial champagnes. Occasionally, a pinkish wine is met, which owes its color to partial extraction from the grape skins and is the result of accident rather than design. 

Fig. 6.37. Cross-section of grape skin (Chardonnay variety). Observation under an optical microscope after coloring with toluidine blue (x 207). Condensation of tannins at different levels in the skin. The darker-colored cells located near the surface of the skin correspond to the maximum condensation of tannins (Amrani-Jontei, 1993)...

This notion of anthocyanin extractability depends on the state of maturity that controls the breakdown of skin cells (Table 6.15). All other conditions being equal, when grapes are perfectly ripe or slightly overripe, the anthocyanin content in the wine is higher than it would have been prior to maturity, although these pigments tend to decrease in grapes. Both color and total phenol content are at a maximum. 

FD C Yellow No. 6 Glucose Grape skin extract Iron oxide black Iron (III) oxide hydrated Iron oxide yellow monohydrate Magnesium carbonate Magnesium stearate Malt extract 1-(Phenylazo)-2-naphthylamine Pyrogallol Riboflavin Talc Zinc chloride colorant, plastics... 

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