Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-06-09
2001-12-11
Aulakh, Charanjit S. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C554S012000, C568S816000, C568S822000, C568S827000, C568S832000
Reexamination Certificate
active
06329557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for purifying lutein and zeaxanthin from crude marigold extracts that may contain high levels of chlorophyll pigments.
2. Description of the Related Art
The carotenoids comprise a group of natural pigments found abundantly in plants, some fish, crustaceans, birds, algae and bacteria. Within this group of pigments are the yellow carotenoids, including both the carotenes (e.g., &bgr;-carotene) and xanthophylls (e.g., lutein and zeaxanthin), and the red carotenoids, including capsanthin, canthaxanthin and astaxanthin. These yellow and red carotenoids are often present in plants, especially flowering plants, together with other classes of pigments, including primarily green chlorophyll pigments.
Carotenoids and in particular, xanthophylls, from marigold extracts have been used for decades in the poultry industry for pigmentation of broiler skins and egg yolks. Lutein, is present at much higher concentrations than zeaxanthin in marigold extracts. Pigmenting formulations for use in the poultry industry having relatively high concentrations of zeaxanthin have recently appeared on the market, wherein the lutein has been isomerized to yield zeaxanthin (U.S. Pat. No. 5,523,494 to Torres and U.S. Pat. No. 5,973,211 to Rodriguez).
In addition to their commercial importance in the poultry industry, the carotenoids have recently received considerable attention from scientists with respect to their potential role in promoting human health. Compounds like &agr; and &bgr;-carotene, lutein and zeaxanthin have been shown to possess strong antioxidant activity, which may retard or prevent diseases like cancer, arteriosclerosis, cataracts, macular degeneration and others (Bowen, WO98/45241). Lutein and zeaxanthin are the only carotenoids present in the macular region of the human retina and are related to the normal function of the macula responsible for visual acuity. It has also been reported that carotenoids enhance the immune response. Free radicals produced as byproducts of metabolic processes and originating from environmental pollutants (such as nitrogen dioxide and ozone of polluted air, heavy metals, halogenated hydrocarbons, ionizing radiation and cigarette smoke) are implicated as causative factors in many of the above-mentioned diseases. Carotenoids are potent quenchers of the highly reactive oxygen free radicals that can initiate a cascade of detrimental chemical reactions. Carotenoids also function as chain-breaking antioxidants, especially at low partial pressures of oxygen. Thus, carotenoids can work to quench free radical-induced reactions and can also prevent generation of free radicals, thereby limiting free radical/oxidative damage.
Hand-picked marigold petals from
Tagetes erecta
contain one of the highest concentrations of carotenoids found in nature. Industrial scale culture of marigolds and mechanization of the harvesting process have increased the amount of harvested leaves, stems, weeds and other plant parts that are typically obtained along with the flower petals. Oleoresins with high levels of chlorophylls and related compounds are obtained when meals from such raw material are extracted. Consequently, the lutein and zeaxanthin concentrations are relatively lower in such oleoresins than in those obtained from hand picked flowers.
The marigold extracts with high chlorophyll content are normally saponified under alkaline conditions to complete hydrolysis of the carotenoids as well as the chlorophyll. Variable levels of other lipids, chlorophyllins and unsaponifiable matter are also normally present in the reaction mixture. Consequently, the relatively low concentration of xanthophylls in oleoresins from mechanically harvested marigold meals, as well as the variability in levels of contaminating pigments, have impeded the commercial development of xanthophyll products for human consumption. Thus, there remains a need for an industrial process for obtaining lutein and zeaxanthin concentrates of high purity from meals prepared from large-scale, mechanically-harvested marigold cultures, which may have high levels of chlorophyll.
SUMMARY OF THE INVENTION
The present invention provides an industrial scale process for obtaining lutein and zeaxanthin concentrates of high purity using saponified marigold extracts that may have high levels of chlorophyll. It is also an objective of this invention to produce a xanthophyll concentrate, which may have applications for human use, wherein the levels of zeaxanthin and lutein are over 97% of the total carotenoids in the product.
More specifically, the present invention relates to a process for the purification of xanthophylls from a saponified extract. The process comprises the steps of dispersing the saponified extract in water to form a dispersion, mixing the dispersion under conditions such that a portion of any water-soluble compounds dissolves in the water to form an aqueous phase and a residue that is not soluble in water, separating the aqueous phase from the residue, contacting the residue with a nonpolar solvent under conditions such that a portion of any lipid-soluble compounds dissolves in the nonpolar solvent and a portion of the xanthophylls precipitates from the nonpolar solvent to form a precipitate, separating the nonpolar solvent from the precipitate, washing the precipitate with a polar solvent such that at least a portion of any remaining chlorophylls dissolves in the polar solvent, and separating the polar solvent from the precipitate to yield a product comprising the xanthophylls at a desired level of purity.
In one aspect of the invention, the saponified extract is obtained from mechanically-harvested marigolds comprising a mixture of carotenoids and chlorophylls.
In variations, the process may further comprise the steps of: recovering a substantial portion of any carotenoids from both the nonpolar and polar solvents; desolventizing and drying the product under inert atmosphere; and, adjusting the pH of the dispersion to between about 5.0 and 7.0, prior to mixing. The pH may be adjusted by adding an acid selected from the group consisting of phosphoric, sulfuric, hydrochloric, acetic or any mineral or organic acid of similar characteristics.
In further variations, the process may include the additional steps of: adjusting the dispersion to a temperature of between about 45° and 80° C. prior to mixing; and washing the residue with water prior to contacting the residue with the nonpolar solvent, wherein the water used for washing is adjusted to a pH of between about 5.0 and 7.0 and a temperature of between about 45° and 80° C.
In one aspect, the nonpolar solvent is selected from the group consisting of hexane, heptane, cyclohexane, octane, aromatic hydrocarbons, ethers and halogenated hydrocarbons, and the polar solvent is selected from the group consisting of a ketone, an alcohol, an amine, and mixtures thereof.
In another aspect, the xanthophylls in the product comprise a mixture of hydrolyzed lutein and zeaxanthin. The lutein and zeaxanthin may comprise greater than 95% of the carotenoids in the saponified extract. The product may also comprise between 400 to 900 grams of total carotenoids per kilogram of saponified extract. The saponified extract may comprise from about 0 to 20% chlorophylls. The concentration of carotenoids in the dispersion can be between about 0.1 to 15 grams per kilogram of the saponified extract, or more preferably between about 5 to 10 grams per kilogram of the saponified extract.
In another variation of the present process, the nonpolar solvent may be used in a proportion of between about 1 to 25 parts, and more preferably between about 5 to 12 parts, of solvent for each part of residue. The polar solvent may be used in a proportion of between 1 to 15 parts, and more preferably between about 4 to 10 parts, of solvent for each part of precipitate. The nonpolar and polar solvents may be used at ambient temperature.
In one aspect of the present invention, the product is suitable for administration
Diaz Alejandro
Rodriguez Gustavo
Torres-Cardona Mario-David
Aulakh Charanjit S.
Knobbe Martens Olson & Bear LLP
Prodemex, S.A. DE C.V.
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