RU2436771C1 - Method of extracting xanthophylls from plant material - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to a method of extracting xanthophylls from plant material, involving extraction of xanthophylls, where the plant material is first dried and crushed and extraction is carried out in n-hexane or petroleum ether at room temperature. The extract is separated and sorbed with silica gel, after which silica gel with xanthophylls is separated from the solution and solvent residue is removed. As a rule, silica gel on which xanthophylls are sorbed is transferred into any plant oil and desorption is carried out while stirring the mixture until decolouration of silica gel. The present invention can be used to produce different plant oils rich in xanthophyll ethers or to produce biologically active additives in form of oil solutions which are excellent preventive agents against retinopathy. ^ EFFECT: method enables efficient and fast extraction of desired products of high quality. ^ 2 cl, 4 ex

Description

The invention relates to the production of oil compositions of xanthophyll esters. The invention can be used to obtain various vegetable oils enriched with xanthophyll esters, or to obtain biologically active additives (BAA) in the form of oil solutions, which are excellent prophylactic against retinopathy.

A known method of obtaining a stable luteal paste from essential oil. Lutein paste can be used in foods and food additives. The method includes the following stages: a) dissolving the purified essential oil in alcohol to obtain, after filtration, the dissolved xanthophyll esters in the form of a clear solution; b) purification of the dissolved essential oil containing xanthophyll esters on an ion exchange resin; c) hydrolysis of the clear solution with a base in the presence of a phase transfer catalyst in an alcohol medium; d) rapid cooling of the hydrolyzed solution in water while maintaining an acidic pH in order to obtain insoluble solid material during filtration; f) dissolving the solid material in the ester to obtain an ester layer after filtration; f) drying the ester layer to form a semi-solid residue; g) trituration of the semi-solid residue in alcohol, resulting in crystals of lutein with a basic substance content of about 65% and the alcohol fraction; h) distilling the alcohol fraction to obtain water-insoluble fractions, i) mixing the lutein crystals from step (g) with the water-insoluble fractions from step (h), whereby a stable luteal paste is obtained. The method allows to obtain a stable luteal paste with an approximately 95% yield (RF patent No. 2321582, published April 10, 2008).

The disadvantage of the method of obtaining luteal paste is a complex scheme for the allocation of lutein. It includes 8 stages, among which there is hydrolysis and distillation. These stages are not very desirable when working with xanthophylls, since the latter are unstable substances.

A known method of extraction and saponification of esters of lutein or zeaxanthin from plants containing xanthophyll esters, including extraction of lutein or zeaxanthin esters from these plant sources with a solution containing tetrahydrofuran and alcohol; saponification of the resulting mixture; removal of tetrahydrofuran and alcohol; washing the residue. In this method, the production of lutein and zeaxanthin, extraction and saponification are carried out simultaneously. The alcohol is selected from the group: ethanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 1-propanol and 2-propanol. Extraction is carried out at elevated pH. The solid residue is then separated, tetrahydrofuran is removed from the extract, the residue is washed with an aqueous mixture and lutein or zeaxanthin crystals are collected. PH control required. Marigold petals upon receipt of lutein are pre-crushed. Zeaxanthin is isolated from dereza berries (US Patent 6262284 07/17/2001).

The disadvantage of this method of isolating xanthophylls from plant materials is the saponification stage, which is not desirable when working with xanthophylls, since the latter are unstable. Moreover, there is no need for saponification of xanthophylls, since this process occurs in animals and humans spontaneously, and storage of xanthophylls in the form of diesters allows prolonging storage periods, since diesters of lutein and zeaxanthin are much more stable than lutein and zeaxanthin.

For the prototype, a method was chosen that involves extraction from an oil mixture of plant material containing xanthophylls, a mixture of hexane with alcohol in a homogeneous solution, cooling and crystallization upon cooling. This produces a product with a lutein ester content of more than 80%. The yield of lutein from esters is more than 70%. The method is as follows: at a temperature of 40-85 ° C, the oily residue is mixed with a mixture of ethyl alcohol and hexane until a homogeneous mixture is obtained. 1-15 parts of solvent are consumed per weight part of the oily residue. The percentage of ethyl alcohol in the mixture can be from 10% to 70%. Stirring is carried out for 1-5 hours. Cool the solution to 10-40 ° C, while crystals precipitate, which are separated by centrifugation or filtration. In this case, impurities remain in the mother liquor. The obtained crystalline precipitate was dissolved in hexane at 50-85 ° C, the mixture was shaken for 1-2 hours and the solution was drained over the precipitate. The ratio of solid to solvent is 2: 6. Slowly cool the solution to 3-10 ° C. Cooling time 2-5 hours. When dissolving, different solvents are used. Different solvents will help to remove impurities and increase the yield of the main product. Next, the cold mixture is better to shake for 1.5 to 2 hours. Then the insoluble matter is separated by centrifugation or filtration. The crystals are dried in a vacuum oven, with a drying temperature of 40-50 ° C, a pressure of 0.06-0.095 MPa. The crystals are dried until hexane is completely removed. The product will have a color from yellow to pale brown. The advantage of the described method is that they use organic solvents (ethyl alcohol and hexane), which have low boiling points and are easily removed by vacuum drying, so the product can be used as a food coloring. Another advantage is the low content of impurities in the resulting product (Patent EP 1857441, published November 21, 2007).

The disadvantages of this method are:

- multi-stage method for the allocation of xanthophylls and, as a consequence, a large time cost;

- reuse of cooling and heating processes;

- the use of large volumes of solvents;

- the use of a drying process for very labile compounds such as xanthophylls.

The objectives of the present invention are:

- development of a simple and quick way to obtain xanthophylls from plant materials;

- development of a method for producing xanthophylls without the use of heating and cooling processes.

- development of a production method that simultaneously allows purification of the product, i.e. use of sorption and desorption processes;

- development of a method for producing xanthophylls for oil compositions, which allows to exclude the drying process.

The problem is solved by the proposed method for the isolation of xanthophylls from plant materials, including the extraction of xanthophylls, the plant materials being preliminarily dried and ground, and the extraction is carried out with n-hexane or petroleum ether at room temperature, the extract is separated and sorbed with silica gel, after which the silica gel with xanthophylls is separated and residual solvent is removed. To obtain oil compositions, silica gel with xanthophylls sorbed on it is transferred to any vegetable oil and desorption is carried out, stirring the mixture until the silica gel decolours.

The technical result consists in the fact that the proposed method for the isolation of xanthophylls from plant materials makes it possible to isolate xanthophylls from plant materials using fewer stages and time; using smaller volumes of solvents; without the use of heating and cooling; without using the drying process of the finished product and, as a result, obtaining a better product. Such a process can, in principle, be transformed into a continuous technological process using movable-layer chromatography technology.

The proposed method for the isolation of xanthophylls from plant materials is carried out as follows.

To obtain xanthophyll esters: lutein and / or zeaxanthin, the plant material is dried to an air-dry state without direct sunlight and the dry mixture is ground. Extraction of n-hexane or petroleum ether at room temperature esters of lutein and / or zeaxanthin are extracted from plant materials. The extract is separated from the solid by centrifugation or filtration. Silica gel is added to the extract, the mixture is stirred until the xanthophyll esters are completely adsorbed onto silica gel, i.e. silica gel becomes orange, the solution becomes colorless. Silica gel is separated from the solution, dried to an air-dry state and, if necessary, transferred to any vegetable oil. A mixture of silica gel oil is stirred until the silica gel decolours, then the silica gel is separated from the oil saturated with xanthophylls by centrifugation. Separated silica gel can be used repeatedly.

5-10 ml of oil enriched with xanthophylls according to the described method can be recommended for the prevention of macular degeneration and retinopathy.

It is known that in the petals of the flowers of marigolds of a number of varieties, the accumulation of lutein diesters (in terms of lutein) reaches 5 mg per 1 g of air-dried raw materials, and in the cups of decorative physalis the accumulation of zeaxanthin diesters reaches (in terms of zeaxanthin) 10 mg per 1 g of air -dry raw materials (see Deineka L.A. et al. “Plants of the Belgorod Flora - Sources of Xanthophils,” p. 59., IV All-Russian Scientific Conference “Chemistry and Technology of Plant Substances”, Syktyvkar, 2006).

Example 1. To obtain lutein esters, plant materials — petals of orange marigold flowers of T.erecta or T.patula species — are separated from the flowers and dried to an air-dry state without direct sunlight. The dry mixture is ground. To obtain zeaxanthin esters, plant materials - decorative physalis cups are separated from the stems and dried to an air-dry state without direct sunlight. The dry mixture is ground. For extraction, pre-dried and crushed marigold petals and / or physalis cups are ground at room temperature with the addition of quartz sand under a layer of n-hexane or petroleum ether to obtain a solution containing at least 0.2 mg / l xanthophylls in terms of lutein or zeaxanthin. The extract is separated by filtration or centrifugation, and a solid residue can be used to obtain the next portion of the extract. If the concentration of xanthophylls in the filtrate is less than 0.2 mg / l, it is used for re-extraction from a new portion of plant material. To 100 ml of the filtrate was added 2 g of silica gel L 5/40 µ and the mixture was stirred until the extract was discolored. Silica gel is separated from the solution by filtration or centrifugation, residual solvent is removed by blowing with an inert gas until there is no odor of the solvent. To silica gel, which adsorbed 66.0 mg of xanthophylls, 100 ml of sunflower oil was added and kept under stirring for 5 minutes. The resulting oil is separated from silica gel by filtration or centrifugation. The xanthophyll content in 1 ml of fortified oil is 0.553 mg. The degree of extraction of xanthophylls in this case is 83.9%.

After centrifugation, a new portion of 100 ml of sunflower oil is added to silica gel with the remainder of the adsorbed xanthophylls, mixed and centrifuged, which makes it possible to obtain an oil containing 0.088 mg of xanthophyll in 1 ml. This allows an additional 13.3% xanthophylls to be extracted. This oil can be used to extract xanthophylls from a new portion of the material.

After that, silica gel is washed from the sorbed substances with acetone, residual solvent is removed by blowing with an inert gas until there is no odor of the solvent, and used again.

Example 2. To 1 g of silica gel, adsorbed according to the proposed method, 29.4 mg of xanthophylls is poured into 50 ml of sunflower oil and kept under stirring for 5 minutes The resulting oil is separated from silica gel by filtration or centrifugation. The xanthophyll content in 1 ml of fortified oil is 0.457 mg. The degree of extraction of xanthophylls in this case is 77.7%.

After centrifugation, a new portion (50 ml) of sunflower oil is added to silica gel with the remainder of the adsorbed xanthophylls, mixed and centrifuged, which allows to obtain an oil containing 0.106 mg of xanthophylls in 1 ml. This allows an additional 18.1% xanthophylls to be extracted. This oil can be used to extract xanthophylls from a new portion of the material.

Example 3. To 1 g of silica gel, which sorbed 29.4 mg of xanthophylls, 50 ml of olive oil was added and kept under stirring for 5 minutes. The resulting oil is separated from silica gel by filtration or centrifugation. The xanthophyll content in 1 ml of fortified oil is 0.473 mg. The degree of extraction of xanthophylls in this case is 80.5%.

Example 4. To 1 g of silica gel, which sorbed 29.4 mg of xanthophylls, 50 ml of linseed oil was added and kept under stirring for 5 minutes. The resulting oil is separated from silica gel by filtration or centrifugation. The xanthophyll content in 1 ml of fortified oil is 0.497 mg. The degree of extraction of xanthophylls in this case is 84.5%.

Based on olive and linseed oils, you can get both functional food products and dietary supplements.

Claims (2)

1. The method of extraction of xanthophylls from plant materials, including the extraction of xanthophylls, characterized in that the plant materials are pre-dried and ground, and the extraction is carried out with n-hexane or petroleum ether at room temperature, the extract is separated and sorbed with silica gel, after which the silica gel with xanthophylls is separated from solution and remove residual solvent. 2. The method according to claim 1, characterized in that the silica gel with xanthophylls adsorbed on it is transferred to any vegetable oil and desorption is carried out, mixing the mixture until the silica gel decolours.