| 摘要 |
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. |
