Exploring the impact of substitution and conformational variations on the copigmentation ability of monomeric flavan-3-ols in wine.

Monomeric flavan-3-ols are important copigments in red wines, due to their superior copigmentation ability and high concentration. In this work, a systematic study was conducted on the copigmentation effects of eight common monomeric flavan-3-ols with malvidin-3-O-glucoside, using experimental and theoretical methods. The results revealed that the addition of a hydroxy group to the B ring and the attachment of a galloyl group at the 3-O position of monomeric flavan-3-ols both contributed to enhance copigmentation, with the latter exerting a more pronounced effect.