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Orientador(es)
Resumo(s)
Carotenoids in grapes of three Port winemaking cultivars were investigated. Extracts were obtained
with n-hexane/diethyl ether mixtures (0/100; 20/80; 50/50; 100/0) and analyzed by normal and reversed
phase HPLC-DAD. Selection and identification of peaks were based on spectroscopic characteristics
- ìmax, (%III/II) and k¢ values, leading to 28 probable carotenoids. Using pure standards, it was possible
to identify seven compounds previously described (neochrome, neoxanthin, violaxanthin, flavoxanthin,
zeaxanthin, lutein, and â-carotene), one more type of neochrome reported here, for the first time,
and in addition, two geometrical isomers of lutein and â-carotene were tentatively described. The
remaining 17 need to be further identified. High polarity solvent mixtures lead to qualitatively richer
chromatograms. Reversed-phase separations allowed the detection of flavoxanthin and the possible
geometrical isomer(s) of â-carotene. Under normal phase, zeaxanthin was detected, and neochromes
were better separated from neoxanthin. Extraction with 50/50 n-hexane/diethyl ether mixtures and
reversed-phase conditions was the best combination for analysis of the carotenoids, known as
precursors of compounds with high aroma impact in wines.
Descrição
Palavras-chave
Port wine grapes Carotenoid identification
Contexto Educativo
Citação
"Journal of Agricultural and Food Chemistry" . ISSN 0021-8561. 52:10 (2004) 3182-3188
Editora
American Chemical Society