Low molecular weight flavans in wine

Abstract

The concentrations of low molecular weight flavans were determined in different wines during the 1990, 1991 and 1992 vintages. Five red wines (Plavac, Trnjak, Vranac, Merlot and Game) and one white (Kujundžuša) were produced from crushed grapes. Pomace contact time was 5 days. Phenolic compounds were fractionated into acidic and neutral groups by passing dealcoholised wines through a preconditioned Sep Pak C₁₈ cartridges. Detailed analyses of major low molecular weight flavan constituents, i.e. (+ )‐catechin, (‐)‐epicatechin and procyanidin dimers B1, B2, B3 and B4, were done using high‐pressure liquid chromatography on reverse phase. The average concentrations of procyanidin dimers of group B in the examined wine samples were higher than the concentrations of the catechin monomers. The dominating dimers were B1 and B2. Procyanidin dimers B3 and B4 were also present but in lower concentrations. The amounts of catechin monomers and procyanidin dimers in wines showed significant varietal and seasonal differences. Highest concentrations were found in wines from Game.