Comparison between the tristimulus measurements Yxy and L∗a∗b∗ to evaluate the colour of young red wines

The chromatic characteristics of 10 young red wines elaborated in the region of Murcia (Spain) were determined. The colour measurements obtained using the Yxy and CIELAB systems were compared. The calculation of dominant wavelength and its representation in the C.I.E. chromatic diagram revealed almost imperceptible differences in the wines classified, while L∗a∗b∗ values achieved a much better differentiation. L∗ and a∗ gave an accurate definition of the wines. L∗ ranged from 37 to 72 while a∗ varied between 23 and 54. One wine sample was clearly different from the others, showing the highest degree of lightness (L∗), the lowest redness (a∗) and the lowest saturation (C∗). The graphical representation of metric lightness difference (ΔL∗) against metric chroma difference (ΔC∗) showed the difference in colour between the wines analyzed. Wine number 1 showed the deepest colour followed by wines numbered 9 and 5, while wine number 7 was very pale. The data obtained were correlated by means of the corresponding matrix of Spearman correlation coefficients, which revealed that the highest correlations existed between L∗ and colour intensity and between L∗ and ionised anthocyanin content.