Studies on the acetaldehyde-induced condensation of (-)-epicatechin and malvidin 3-O-glucoside in a model solution system.
The reaction between (-)-epicatechin, malvidin 3-O-glucoside, and acetaldehyde was studied in a model solution system. Ethyl-linked flavanol oligomers and anthocyanin-flavanol derivatives were observed, showing that the two polyphenols competed in the condensation process. Among the anthocyanin-ethyl-flavanol adducts, dimeric compounds in which the flavanol was linked to the anthocyanin with CH(3)-CH bridges were observed. In addition, trimeric and tetrameric products containing one anthocyanin and one, two, or three flavanols units were detected. A tetrameric product containing two anthocyanin and two flavanol units was also found as a doubly charged ion. No compound containing more than two malvidin 3-O-glucosides was detected, suggesting that only one anthocyanin A ring summit can be included in the polymerization process, which thus stops when both ends are occupied by an anthocyanin moiety. Thioacidolysis of the two isolated anthocyanin-ethyl-flavanol dimeric derivatives showed that anthocyanin-ethyl linkage was not sensitive to such reactants, whereas the flavanol-ethyl one was. In addition, flavanol-ethyl linkages involved in anthocyanin-ethyl-flavanol adducts were found to be less sensitive to those involved in flavan-ethyl dimers.
Es-Safi
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ISVV-INRA Institut des Produits de la Vigne, Unité de Recherche Biopolymères et Arômes, Montpellier, France.
Fulcrand
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H
Cheynier
V
V
Moutounet
M
M
D000079:Acetaldehyde; D000872:Anthocyanins / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000737:chemistry; D008956:Models, Chemical
D000872:Anthocyanins; D005419:Flavonoids; D002392:Catechin; D000079:Acetaldehyde