Reactivity comparison of three malvidin-type anthocyanins forming derived pigments in model wine solutions

Abstract

Malvidin-3-O-glucoside (MvG), malvidin-3-O-(6-O-acetyl)-glucoside (MvAG), and malvidin-3,5-O-diglucoside (MvDG) are three representative malvidin-type anthocyanins in red wine. In this study, the influence of structural differences on the formation efficiency of two types of derived pigments ((-)-epicatechin-ethyl-anthocyanins and pyranoanthocyanins) was investigated in model solutions using UHPLC-MS. The results showed that the yields of MvAG were higher than those of MvG to form both types of derived pigments, and the formation rate of pyranoanthocyanin was also relatively higher. In contrast, acetylation slowed the formation of (-)-epicatechin-ethyl-anthocyanins, indicating that the rate of covalent reactions may be linked to the affinity of (-)-epicatechin to copigment with anthocyanins. The condensation rate of MvDG with (-)-epicatechin, mediated by acetaldehyde, was much lower than that of the two monoglucosidic anthocyanins and also exhibited lower yields. In addition, pyranoanthocyanin was not generated from MvDG due to the absence of a free hydroxyl group at the C5 position.

Keywords: Acetylated anthocyanin; Diglucosidic anthocyanin; Polymerization; Pyranoanthocyanin; UHPLC-MS.