Interactions of Oligomeric Procyanidins in Model Wine Solutions Containing Malvidin-3-Glucoside and Acetaldehyde

TLDR

The study examined how grape seed flavanols (dimeric, galloylated dimeric, and trimeric procyanidins) interact with malvidin‑3‑glucoside and acetaldehyde in wine‑like model solutions. Malvidin‑3‑glucoside and oligomeric procyanidins reacted slowly, forming yellow xanthylium salts, but their concentrations decreased more rapidly in the presence of acetaldehyde, producing violet‑shifted color from new CH3CH‑bridged compounds; the degradation rate varied with component complexity, with monomers reacting slower than dimers and the trimer exhibiting the fastest loss.

Abstract

Interactions of grape seed flavanols, dimeric, galloylated dimeric and trimeric procyanidins with malvidin-3-glucoside and acetaldehyde were studied in wine-like model solutions. Malvidin-3-glucoside and oligomeric procyanidins reacted very slowly, with eventual formation of yellow xanthylium salts. The concentrations of malvidin-3-glucoside and oligomeric procyanidins decreased faster in the presence of acetaldehyde and the colour augmentation with shift towards violet was attributed to the formation of new coloured compounds, detectable by HPLC and linked at different positions by CH3CH bridges. The rate of loss of procyanidins in the presence of malvidin-3-glucoside and acetaldehyde varied according to the complexity of the components. Monomeric (+)-catechin and (-)-epicatechin reacted more slowly than dimer procyanidins B1, B2 and B3 while trimer C1 (epicatechin 4β→8 epicatechin 4β→8 epicatechin) presented the highest degradative reaction rate.