Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1999-11-24
2003-01-07
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06504067
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention refers to an industrial process to obtain xanthophyll concentrates of high purity from sources of plant origin, suitable for human or animal consumption and, more specifically, to a process of refining plant extracts by means of treatment with dilute alkali, followed by treatment with a dilute acid.
2. Description of the Related Art
Carotenoids are natural pigments that are widely found in vegetable and animal species. It comprises the family of Carotenes, which are hydrocarbon carotenoids such as: &bgr;-carotene and lycopene, and the hydroxy or oxy carotenoids, such as lutein, zeaxanthin, capsanthin, capsorrubin, astaxanthin, bixin, crocetin and others.
Carotenoids are widely produced on a large scale in nature, in plants (leaves, flowers and fruits), microalgae, fungii and bacteria.
Since animals do not have the capacity to biosynthesize carotenoids, they can only take advantage of the carotenoids found in natural sources for different purposes, such as, acquiring color (birds and fish) or to accomplish metabolic and reproductive functions (crustaceans), among others.
In recent years, it has been widely documented by scientific evidence that some carotenoids, for example, lutein and zeaxanthin among others, provide beneficial effects to the human being. It has been widely shown that their natural antioxidant properties reduce the risk of tissue degenerative diseases such as cancer, and also help to prevent macular degeneration in adults.
An abundant and varied diet composed of fresh fruits and vegetables should be generally regarded as ample enough to satisfy the carotenoid requirements of a human being. However, nowadays an unbalanced and deficient human diet lacks the required amounts of lutein, zeaxanthin and other carotenoids. It is for such reason that it has become very desirable to find alternate natural sources of carotenoids having a high concentration and purity.
Lutein and zeaxanthin occur widely in nature in fresh vegetables like spinach, broccoli, green peas, brussel sprouts, squash as well as in fresh fruits like mangoes, papaya, peaches, oranges, etc., and also in alfalfa.
In some vegetables, the xanthophylls are found in their free form. However, in most instances they are found as diesters of fatty acids, such as myristic, lauric and palmitic acids. In order to assimilate those xanthophylls, the organism hydrolyses the diesters so that absorption occurs and enables the organism to metabolize them.
In the last few decades there has been an increased worldwide production of marigold (
Tagetes erecta
). Marigold flowers contain a high concentration of xanthophylls, predominantly lutein, and some zeaxanthin. Such source of xanthophylls is widely used by the feed industry in order to obtain a good pigmentation in broilers and egg yolks.
Only recently has a growing demand developed in order to supplement the human diet with such xanthophylls. For such reason, it is timely to develop processes with economic feasibility to concentrate and purify the xanthophylls for human consumption, such as lutein and zeaxanthin, among others.
In the research works of Tcyczkowski and Hamilton, reported in
Poultry Science
70(3):651-654, 1991, they developed a laboratory analytical technique to isolate and crystallize lutein (and zeaxanthin) from a saponified marigold extract, by using organic solvents, that it is not viable to be carried out at an industrial process level. Furthermore, such solvents can leave noxious residues which are trapped or occluded in the crystals.
The use of solvents like methanol or halogenated organic solvents like dichloromethane or dichloroethane as in U.S. Pat. No. 5,382,714, of Khachik et al, 1995, implies crystallization and recrystallization processes, low temperatures, etc., in order to obtain highly pure lutein crystals. The use of solvents with a high level of toxicity requires an expensive and elaborated equipment to handle such solvents, and may result non feasible at an industrial production level.
In U.S. Pat. No. 5,648,564 granted to Ausich et al in 1997, they “surprisingly” found that upon the saponification of the marigold oleoresin with an aqueous alkali diluted with propylene glycol, lutein crystals appeared. It is known to people skilled in the art that the fatty acid diesters of xanthophylls are soluble in non-polar aliphatic solvents that have a high affinity for fats, such as aliphatic solvents (hexane, pentane, etc.). Upon hydrolyzing the xanthophylls, they become insoluble in aliphatic solvents and/or water, but they are highly soluble in polar solvents, such as ketones, alcohols, chlorinated solvents etc. It is known also, that lutein and zeaxanthin occur always as minute crystals during the aqueous phase saponification reaction of the marigold oleoresin, unless it is carried out in the presence of polar solvents. Such occurrence is widely recognized in the art when the hydrolysis of the xanthophyll diesters is carried out in a non-polar media (alkaline water or alkaline water plus propylene glycol).
In the process of the present invention, we have been able to obtain xanthophyll concentrates having a high purity, in a simple manner, using non toxic reagents that are not dangerous to handle, and without requiring expensive equipment or costly low temperature crystallization steps. Starting from the principle that by employing the same and only solvent (hexane) that is used in the industry to obtain the xanthophyll diesters extraction from the plant material (oleoresin), followed by a simple procedure by which the xanthophylls become insoluble in said solvent, the impurities and all the undesired material (all of them soluble in hexane) are separated or removed with the use of the same hexane solvent, producing a xanthophyll concentrate of high purity.
As it will be explained hereinafter in further detail, by this process lutein and zeaxanthin concentrates are obtained having a high degree of purity when Tagetes oleoresin is used as the raw material. By the process of the present invention, capsanthin and capsorrubin concentrates of high purity are also obtained when Capsicum oleoresin is used as the raw material.
This is a novel process wherein the impurities are eliminated or removed in the different stages, while the xanthophylls concentrate is enriched after each stage. In all other known processes or methods, the xanthophylls are selectively extracted from the xanthophylls containing mass by means of different solvents that commonly are expensive or dangerous, or use costly low temperature crystallization and recrystallization processes, wherein pigment loss may occur.
This process to concentrate and purify xanthophylls like lutein, zeaxanthin, capsanthin and capsorrubin starting from botanical extracts, is surprisingly efficient, economical and clean.
SUMMARY OF THE INVENTION
The first step of this process comprises refining the oleoresin from which several undesirable materials such as free fatty acids, gums, waxes, sterols, phosphatides, lipids, clorophylls, volatile compounds etc., are removed. This refining operation is carried out in a first step by a gentle treatment of the oleoresin with a dilute alkali and separating the impurities by means of a centrifugal machine. After thoroughly rinsing and separating the aqueous phase from the oleoresin, a treatment with a dilute acid is carried out. The oleoresin is thoroughly rinsed again, and the aqueous phase is removed by centrifugation.
In the enriched oleoresin obtained from the previous step, the xanthophylls are found as diesters of fatty acids. The second step of the process comprises hydrolyzing the diesters in order to obtain free xanthophylls. The diester hydrolysis is carried out with an aqueous alkali, in the presence of emulsifiers. This reaction is performed without the use of alcohols or organic solvents.
The third step of this process comprises diluting the saponified mass with water and reducing the pH of the concentrate dispersion by adjusting it with a diluted acid until a slight acid re
Elizondo-Mireles Juan-Roberto
Montoya-Olvera Ricardo
Torres-Gómez Carlos-Javier
Torres-Quiroga Jose-Odon
Abelman ,Frayne & Schwab
Industrial Organica S.A. DE C.V.
Shippen Michael L.
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