Exploring the relationship between metal ion valency and electron transfer in copigmentation processes of cyanidin-3--glucoside in simulated fruit wine solutions.

In this experiment, five metal ions (K, Mg, Al, Ga, and Sn) were utilized as copigments to investigate their copigmentation processes with cyanidin-3--glucoside (C3OG) in simulated fruit wine solutions. The color characteristics were analyzed using Glories and CIELAB methods, and the copigmentation effects were determined spectrophotometrically. Thermodynamic parameters, including the equilibrium constant () and standard Gibbs free energy (Δ°), were calculated to comprehend the binding affinity between metal ions and C3OG.