Significance of CIELAB parameters in the routine analysis of red wines

Abstract

Correlations have been sought among different parameters (total polyphenols, anthocyanins and flavonoids, monomeric anthocyanins, Zn, Cu, Mn, and Fe) analyzed in two consecutive vintages of a Tempranillo wine. A comparative study of those parameters with color characteristics (both CIELAB and Glories parameters) is presented for these wines. Principal Component Analysis (PCA) has showed the existence of a close relationship between CIELAB parameters and polyphenol concentrations, whereas no correlation could be found with classic color parameters but in the expected case of Color Intensity (CI). An equation is proposed that allows the concentration of total polyphenols to be estimated as a function of total anthocyanins, cyanidin-3-glucoside (Cy-3-gluc), and petunidin-3-glucoside (Pt-3-gluc) concentrations. Chromatographic fractioning of wine samples evidenced the specific interaction of both Pt-3-gluc and Cy-3-gluc with Fe, Zn, and Cu.