A comprehensive study on the colour of virgin olive oils and its relationship with their chlorophylls and carotenoids indexes (II): CIELUV and CIELAB uniform colour spaces

The colour of up to 1700 virgin olive oil samples obtained from diverse Spanish varieties and from drupes at different maturity stages was analyzed by considering the CIELAB and CIELUV uniform colour spaces. When all the samples were considered altogether it was noticed that the range huv was considerably wider numerically than that of hab, and so was the range of Cab∗ to that of Cuv∗. Regarding the simple regressions analyses of the relationships colour coordinates-pigments it the best correlations were found between the carotenoid index and Cab∗ and b∗. When multiple linear regression analyses were applied considering the sets of scalar coordinates (L∗u∗v∗ and L∗a∗b∗) and angular coordinates (L∗Cuv∗huv and L∗Cab∗hab) separately as independent variables values of R2 nearing 0.9 were obtained. However, the strongest correlations of all (R2 > 0.9) were obtained by means of general linear model multiple regression models considering non-redundant CIELAB sets of coordinates and suv∗.