ISOLATION, IDENTIFICATION, AND CHARACTERIZATION OF NEW COLOR-STABLE ANTHOCYANINS OCCURRING IN SOME RED WINES

Four new anthocyanin pigments were found in red wines in trace amounts and are thought to be formed in wines during maturation. Their struct ures were established by FAR-MS and NMR. Two pigments were identified as the 3-glucoside (vitisin A) and the 3-acetylglucoside (acetylvitisi n A) of malvidin containing a C3H2O2 grouping, linking carbon 4 and th e 5-hydroxyl group of its molecule (vitisidin A). The other two anthoc yanins were identified as the 3-glucoside (vitisin B) and the 3-acetyl glucoside (acetylvitisin B) of malvidin containing a CH=CH moiety link ing carbon 4 and the 5-hydroxyl group of its molecule (vitisidin B or decarboxyvitisidin A). Unlike other anthocyanins these novel compounds were found to be wholly or partly resistant to bleaching by sulfur di oxide and express more color up to pH 7 than malvidin S-glucoside. Det ailed spectral measurements from 250 to 770 nm up to pH 7, including t he use of CIELAB 76 measurements, indicate the formation of stable qui nonoidal bases, confirming that there could be Little formation of the colorless carbinol base forms.