Trans-xanthophyll ester concentrates having a trans-xanthophyll ester content of at least four times greater and preferably at least nine times greater than the cis-xanthophyll ester content are obtained. Xanthophyll ester concentrates having a total xanthophyll ester content of at least 40 wt. % and preferably greater than about 55 wt. % are also obtained. A method of obtaining a trans-xanthophyll ester concentrate of high purity includes contacting plant material containing xanthophyll esters with a hydrocarbon solvent for a time sufficient to extract xanthophyll esters from the plant material, separating the hydrocarbon solvent and extract dissolved therein from the remaining plant material, evaporating the hydrocarbon solvent from the dissolved extract to obtain a crude xanthophyll ester concentrate, admixing the crude xanthophyll ester concentrate with an alcohol at approximately ambient temperature to dissolve non-xanthophyll impurities and cis-xanthophyll esters from the concentrate and removing the alcohol containing impurities and cis-xanthophyll esters from the crude trans-xanthophyll concentrate to obtain a purified trans-xanthophyll ester concentrate. By using only the corollas of marigold flowers, lutein ester concentrates of high purity are obtained with pesticide residues absent from the concentrate at parts per billion detection levels.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on U.S. provisional patent application Ser. No. 60/082,293, filed Apr. 20, 1998 and Ser. No. 60/085,804, filed May 18, 1998, the disclosures of which are incorporated herein by reference.
The present invention relates to a method for the production of a lutein-fatty acid ester concentrate of high purity by dissolving marigold oleoresin in a ketone solvent such as acetone, cooling the solution, and removing wherefrom a ketone solvent-insoluble component to uniform the quality of oleoresin, followed by dissolving the acetone-soluble portion obtained as above in butanol, cooling the solution, removing a butanol-soluble impurity after adding or without adding one or more members selected from the group consisting of water, methanol, ethanol and a mixture thereof, and washing the resulting butanol-insoluble with ethanol.
A method for concentrating trans-lutein esters from marigold oleoresin, which includes blending the oleoresin with a solvent and a co-solvent of lower alkanols and recovering a precipitate enriched with trans-lutein esters at a temperature of above 22.degree. C. The recovery of the trans-lutein esters is greater using the alkanol blend than when using only a lower alkanol in the said blend. The process is most useful using a lower-grade, commercially available oleoresin, thereby helping small producers, who do not have access to higher-grade oleoresin made through backward integration to marigold cultivation and harvest.
The present invention provides an industrial scale process for obtaining lutein and zeaxanthin concentrates of high purity from saponified marigold extracts that may have high levels of chlorophyll.
Monoesters, diesters and polyesters are provided wherein both the acid-derived moiety and the alcohol-derived moiety of the esters are carotenoid compounds. The synthetic ester linkage between two or more carotenoids provides new compounds in which the similar and complementary properties of the individual carotenoids are combined. The new all-carotenoid esters may be useful as antioxidants, therapeutic agents, pigmenting ingredients in poultry feed or as coloring agents for fats. The polyesters have the potential to act as molecular wires with unique electrical conductance characteristics. The all-carotenoid esters may be prepared from the esterification of at least one hydroxy carotenoid with at least one carboxylic carotenoid, or via the reaction of the acid chloride of a carboxylic carotenoid with a hydroxy carotenoid. Preferred hydroxy carotenoids include lutein, zeaxanthin, cryptoxanthin, violaxanthin, carotene diol, hydroxy carotene, hydroxylycopene, alloxanthin and dehydrocryptoxanthin. Preferred carboxylic carotenoids include bixin, norbixin, .beta.-apo-8-carotenoic acid, crocetin, diapocarotenoic acid, carboxylcarotene and azafrin.
A novel xanthophyll esters concentrate including a composition containing lutein and zeaxanthin fatty acid esters wherein the composition contains by weight 90-95% of trans-lutein esters, 0-5% of cis-lutein esters and 3.5 to 6% of zeaxanthin esters. More particularly, a process is provided for the preparation of the above concentrate employing ketonic solvents. The novel trans-lutein enriched xanthophyll ester concentrate is useful for human consumption, either as nutraceuticals, as nutritional supplements, as food additives and also for coloring animal feeds. The concentrate has better stability and bioavailability.
