Preparative isolation of anthocyanins by high-speed countercurrent chromatography and application of the color activity concept to red wine.

Red pigments were isolated from wine and grape-skin extracts using preparative high-speed countercurrent chromatography (HSCCC) and identified by NMR and MS techniques. Four solvent systems were developed in order to separate anthocyanins with different polarities. Malvidin-3-glucoside was the major component present in young red wines, and up to 500 mg of pure malvidin-3-glucoside could be obtained from a single bottle of a red wine. Other isolated pigments were the malvidin- and peonidin-3,5-diglucosides, as well as acetyl-, coumaroyl-, and caffeoyl-derivatives of anthocyanins. Furthermore, condensed red wine pigments formed from malvidin-3-glucoside (vitisin A and acetylvitisin A) were isolated on a preparative scale. Isolated compounds were used as standards for quantification of anthocyanins in a range of red wines. The "color activity concept" was applied to red wine, and visual detection thresholds were determined for some of the isolated anthocyanins. Mono-glucosides were found to exhibit lower visual detection thresholds than di-glucosides and acylated anthocyanins.