Malvidin glucoside-ethyl-catechin is a flavanol-anthocyanin adduct.

[1][2] Flavanol-anthocyanin adducts are formed during wine ageing through reactions between anthocyanins and tannins present in grape, with yeast metabolites such as acetaldehyde.

Acetaldehyde-induced reactions yield ethyl-linked species such as malvidin glucoside-ethyl-catechin.

[3][4] This compound has a better color stability at pH 5.5 than malvidin-3O-glucoside.

[5] Other types of aldehyde, such as isovaleraldehyde, benzaldehyde, propionaldehyde, isobutyraldehyde, formaldehyde or 2-methylbutyraldehyde, show the same reactivity in model solutions.