Geometrical isomers of violaxanthin in orange juice

Journal of Agricultural and Food Chemistry, 1991

To have a better assessment of major carotenoids, there is a need to systematically elucidate cis isomers of these polyenes. The combination of separation (Vydac and Zorbax c 1 8 columns), spectral ratios (DB/DII and D~/DIII), and spectral characteristics was used to help identify cis/trans isomers. The less lipophilic carotenoids are better separated by the Zorbax column and the more lipophilic carotenes by the Vydac column. The optimized isocratic mobile-phase composition for both columns was CH3CN: CHaOH:CHzC12 (8018:2). One to four cis isomers were differentiated from their corresponding trans isomers in four acyclic (phytoene, phytofluene, {-carotene, and lycopene) and three cyclic (y-carotene, @-carotene, and lutein) Carotenoids. The DB/DII ratios were used to predict conjugated double bonds between 9 and 11 and the DII/DIII ratios for conjugated double bonds between 3 and 7.

Journal of Food Composition and Analysis, 2007

Aside from the nutritional relevance of some carotenoids owing to their vitamin A activity, these pigments are increasingly drawing the interest of researchers as they may be somehow implicated in the prevention and/or protection against major human diseases. Orange juice is an important source of carotenoids, which, along with its nutritional importance worldwide, have stimulated the development of diverse analytical

Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as 'functional food ingredients'. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

Food Chemistry, 2008

Research on the biosynthesis of carotenoid pigments, from diverse points of view, has undergone a considerable boost in recent years due to the large body of studies that highlights their beneficial effects in humans. To obtain valuable information from such surveys, it is of paramount importance to reduce the tentativeness with which some carotenoids are still identified, above all, when they are key compounds for the synthesis of other important metabolites. This is the case for neoxanthin (5 0 ,6 0-epoxy-6,7-didehydro-5,6,5 0 ,6 0-tetrahydrob,b-carotene-3,5,3 0-triol), an epoxycarotenoid which can be found in the light harvesting apparatus of plants and whose cleavage leads to the formation of xanthoxin and then of the plant hormone abscisic acid, among other compounds. Hence, this paper presents pieces of evidence that may put in doubt the presence of such a carotenoid in orange juice, as a consequence of which we propose that the compound formerly tentatively identified as neoxanthin should be referred to as ''unidentified" prior to its conclusive characterization and identification.

Analytical Chemistry, 2006

Journal of Separation Science, 2009

Current Research in Nutrition and Food Science Journal, 2015

Carotenoids are a class of natural pigments familiar to all through the orange-red colours of popular foods like oranges, tomatoes and carrots and the yellow colour of many flowers. They have been studied for a number of years because of their diverse roles in photobiology, photochemistry and photo medicine. Carotenoids are also added as colorants to many manufactured foods, drinks, and animal feeds, either in the forms of natural extracts (e.g annatto, paprika or marigold extracts) or as pure compounds manufactured by chemical synthesis. Carotenoids are often described as provitamins A, as this particular vitamin is a product of carotenoid metabolism. The distribution of carotenoids among the different plant groups shows no obvious pattern. b-Carotene is the most abundant in leafy vegetables, though the colour is masked by its co-existence with chlorophyll, and this carotenoid has the highest vitamin A activity. Zeaxanthin, a-carotene and antheraxanthin are also present in small am...

Journal of Agricultural and Food Chemistry, 2004

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 λ max , (%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 -carotene), one more type of neochrome reported here, for the first time, and in addition, two geometrical isomers of lutein and -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 -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.

Food Research International, 2010

This study was conducted to gain insight into the influence of the chemical structure of carotenoids in the colour of orange juices. For this purpose we correlated the colorimetric information of commercially available OJ with their carotenoid content by means of multiple regressions We have concluded that the carotenoids better correlated to the hue are not necessarily the same as those mainly related to the chroma. According to our statistical analyses, the pigments mainly related to h ab were zeinoxanthin, lutein and a mixture of violaxanthin isomers, whilst those mainly related to C Ã ab were zeaxanthin, (9Z)-or (9 0 Z)-antheraxanthin and zeinoxanthin. These findings are very interesting for the citrus industry, since some carotenoids are used as colorants and the colour of OJ does influence the consumers' choices.