Résumé
Flavanol-anthocyanin (F-A(+)) adducts were detected in red wine. A mechanism involving acid-catalysed cleavage of flavanol oligomers followed by nucleophilic addition of the anthocyanin moiety (in its hemiketal form) to the resulting carbocation (F+) was postulated. To confirm this mechanism, reactions between malvidin3-O-glucoside (Mv3glc) and procyanidin dimerepicatechin-(4-8)-epicatechin 3-O-gallate (B2-3'OG) were studied in a model solution system at pH 2. A new pigment with a UV-Vis spectrum similar to that of Mv3glc and a signal at m/z = 781 in the positive ion mode was detected and was attributed to Ec-Mv3glc, in agreement with the proposed reaction pathway