| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 101.05 KB | Adobe PDF |
Advisor(s)
Abstract(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.
Description
Keywords
Port wine grapes Carotenoid identification
Citation
"Journal of Agricultural and Food Chemistry" . ISSN 0021-8561. 52:10 (2004) 3182-3188
Publisher
American Chemical Society