| Abstract
| - Carotenoids in grapes of three Port winemaking cultivars were investigated. Extracts were obtainedwith n-hexane/diethyl ether mixtures (0/100; 20/80; 50/50; 100/0) and analyzed by normal and reversedphase HPLC-DAD. Selection and identification of peaks were based on spectroscopic characteristics− λmax, (%III/II) and k‘ values, leading to 28 probable carotenoids. Using pure standards, it was possibleto identify seven compounds previously described (neochrome, neoxanthin, violaxanthin, flavoxanthin,zeaxanthin, lutein, and β-carotene), one more type of neochrome reported here, for the first time,and in addition, two geometrical isomers of lutein and β-carotene were tentatively described. Theremaining 17 need to be further identified. High polarity solvent mixtures lead to qualitatively richerchromatograms. Reversed-phase separations allowed the detection of flavoxanthin and the possiblegeometrical isomer(s) of β-carotene. Under normal phase, zeaxanthin was detected, and neochromeswere better separated from neoxanthin. Extraction with 50/50 n-hexane/diethyl ether mixtures andreversed-phase conditions was the best combination for analysis of the carotenoids, known asprecursors of compounds with high aroma impact in wines. Keywords: Port wine grapes; carotenoid identification
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