Correlation for pigment content through colour determination using tristimulus values in a green leafy vegetable, swiss chard

Abstract The relationship between colour parameters of the chlorophylls and carotenoids in the green leaves of Swiss chard was studied. Using the Hunter colour parameters (L*, a *, b *, chroma and hue angle) we found a correlation coefficient r 2 = 0.9264 for the chlorophylls and r 2 = 0.8595 for carotenoids. The chlorophyll a, b plus chlorophyllide a, b extraction and the carotenoid extraction were carried out on the whole tissue using N,N ‐dimethylformamide as solvent. Using between 10 and 50 mg tissue, the extractions with 3 ml solvent for 14–16 h at 4°C in darkness were quantitative for the chlorophylls; for the carotenoids, the same procedure indicated a content approximating to the level of provitamin A present in the leafy vegetable.