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Updated: Sep 13, 2025

Visualizing Visual Adaptation
Published on: April 24, 2017
The Role of Copigmentation in Colour Attributes and Their Evolution in Model Wine: A Thermodynamic and Colorimetric
Arianna Ricci1,2, Cristian Galaz-Torres1,2, Giuseppina Paola Parpinello1,2
1Department of Agricultural and Food Sciences (DISTAL), Alma Mater Studiorum-University of Bologna, Piazza Goidanich 60, 47521 Cesena, FC, Italy.
Abstract:
The colour evolution of malvidin-3-O-glucoside (Mv-3-O-glc) elicited by caffeic acid (CAF), (+)-catechin (CA), or syringic acid (SI) was spectrophotometrically monitored in model wine solution, modulating the malvidin-to-polyphenol molar ratio (1:1 to 1:20) and the pH (2.8-3.8). The spectral features provided the thermodynamic parameters Gibbs free energy (ΔG0) and equilibrium constant (Keq), showing that the copigmentation extent is maximized at pH 3.6 and a higher molar ratio (1:20), and that copigments have different efficiency. In a long-term evolution (12 months), transient complexes evolved into different colour characteristics. Spectrophotometry and colorimetry (chroma C*, hue H*, and lightness L*) revealed the formation of stable pigments with peculiar orange-reddish colour when CAF was present; however, in the case of CA, an accentuated yellow tone was observed. SI showed minimum impact in the long-term evolution of Mv-3-O-glc. This study expands knowledge on oenological copigmentation, further exploring its potential implication in the colour of aged red wines.
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