Copigmentation and anti-copigmentation in grape extracts studied by spectrophotometry and post-column-reaction HPLC

► Copigmentation interactions in complex solutions similar to wine were studied. ► Spectrophotometry, HPLC and post column reaction methods were followed. ► Our results suggest a competing equilibrium. ► This can provoke a hypochromic (anti-copigmentation) effect. ► Competition between flavonols (our best copigments) and flavanols was highlighted.