CN116254156A - Improved urea inclusion process for the enrichment of polyunsaturated fatty acids - Google Patents
Improved urea inclusion process for the enrichment of polyunsaturated fatty acids Download PDFInfo
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- CN116254156A CN116254156A CN202310410945.XA CN202310410945A CN116254156A CN 116254156 A CN116254156 A CN 116254156A CN 202310410945 A CN202310410945 A CN 202310410945A CN 116254156 A CN116254156 A CN 116254156A
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 168
- 239000004202 carbamide Substances 0.000 title claims abstract description 166
- 238000000034 method Methods 0.000 title claims abstract description 50
- 235000020777 polyunsaturated fatty acids Nutrition 0.000 title claims abstract description 42
- 230000008569 process Effects 0.000 title claims description 33
- 125000004494 ethyl ester group Chemical group 0.000 claims abstract description 63
- 239000002904 solvent Substances 0.000 claims abstract description 51
- 239000000194 fatty acid Substances 0.000 claims abstract description 50
- 235000014113 dietary fatty acids Nutrition 0.000 claims abstract description 46
- 229930195729 fatty acid Natural products 0.000 claims abstract description 46
- 150000004665 fatty acids Chemical class 0.000 claims abstract description 46
- 239000013078 crystal Substances 0.000 claims abstract description 28
- 239000000203 mixture Substances 0.000 claims abstract description 27
- 239000003960 organic solvent Substances 0.000 claims abstract description 27
- 238000002156 mixing Methods 0.000 claims abstract description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 119
- 241000195493 Cryptophyta Species 0.000 claims description 50
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 46
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 31
- 239000003208 petroleum Substances 0.000 claims description 23
- 238000001704 evaporation Methods 0.000 claims description 17
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 14
- 230000008020 evaporation Effects 0.000 claims description 13
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 8
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims description 6
- 238000000265 homogenisation Methods 0.000 claims description 5
- 230000006837 decompression Effects 0.000 claims description 4
- 239000012046 mixed solvent Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 235000019387 fatty acid methyl ester Nutrition 0.000 claims description 2
- 235000021588 free fatty acids Nutrition 0.000 claims description 2
- 238000002425 crystallisation Methods 0.000 abstract description 20
- 230000008025 crystallization Effects 0.000 abstract description 19
- 150000004702 methyl esters Chemical class 0.000 abstract description 3
- 235000019441 ethanol Nutrition 0.000 description 34
- 239000011259 mixed solution Substances 0.000 description 22
- 239000000243 solution Substances 0.000 description 22
- 239000000047 product Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- MBMBGCFOFBJSGT-KUBAVDMBSA-N all-cis-docosa-4,7,10,13,16,19-hexaenoic acid Chemical compound CC\C=C/C\C=C/C\C=C/C\C=C/C\C=C/C\C=C/CCC(O)=O MBMBGCFOFBJSGT-KUBAVDMBSA-N 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 238000002390 rotary evaporation Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 235000020669 docosahexaenoic acid Nutrition 0.000 description 8
- 229940090949 docosahexaenoic acid Drugs 0.000 description 7
- 239000000839 emulsion Substances 0.000 description 7
- 239000000706 filtrate Substances 0.000 description 7
- 239000003495 polar organic solvent Substances 0.000 description 6
- 238000005303 weighing Methods 0.000 description 6
- 238000004321 preservation Methods 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 150000004671 saturated fatty acids Chemical class 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000012467 final product Substances 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 238000009775 high-speed stirring Methods 0.000 description 2
- 150000002632 lipids Chemical class 0.000 description 2
- 238000010907 mechanical stirring Methods 0.000 description 2
- GTCAXTIRRLKXRU-UHFFFAOYSA-N methyl carbamate Chemical compound COC(N)=O GTCAXTIRRLKXRU-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000012454 non-polar solvent Substances 0.000 description 2
- 239000002798 polar solvent Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- DVSZKTAMJJTWFG-SKCDLICFSA-N (2e,4e,6e,8e,10e,12e)-docosa-2,4,6,8,10,12-hexaenoic acid Chemical compound CCCCCCCCC\C=C\C=C\C=C\C=C\C=C\C=C\C(O)=O DVSZKTAMJJTWFG-SKCDLICFSA-N 0.000 description 1
- GZJLLYHBALOKEX-UHFFFAOYSA-N 6-Ketone, O18-Me-Ussuriedine Natural products CC=CCC=CCC=CCC=CCC=CCC=CCCCC(O)=O GZJLLYHBALOKEX-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241000199912 Crypthecodinium cohnii Species 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 235000013877 carbamide Nutrition 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- KAUVQQXNCKESLC-UHFFFAOYSA-N docosahexaenoic acid (DHA) Natural products COC(=O)C(C)NOCC1=CC=CC=C1 KAUVQQXNCKESLC-UHFFFAOYSA-N 0.000 description 1
- YJVCRVPZGVVAEQ-UHFFFAOYSA-N ethanol;methanol;propan-2-one Chemical compound OC.CCO.CC(C)=O YJVCRVPZGVVAEQ-UHFFFAOYSA-N 0.000 description 1
- XTLNYNMNUCLWEZ-UHFFFAOYSA-N ethanol;propan-2-one Chemical compound CCO.CC(C)=O XTLNYNMNUCLWEZ-UHFFFAOYSA-N 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000012456 homogeneous solution Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000013332 literature search Methods 0.000 description 1
- -1 methanol Chemical compound 0.000 description 1
- NIQQIJXGUZVEBB-UHFFFAOYSA-N methanol;propan-2-one Chemical compound OC.CC(C)=O NIQQIJXGUZVEBB-UHFFFAOYSA-N 0.000 description 1
- 235000021281 monounsaturated fatty acids Nutrition 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
- C11C1/02—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids from fats or fatty oils
- C11C1/025—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids from fats or fatty oils by saponification and release of fatty acids
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
- C11C1/005—Splitting up mixtures of fatty acids into their constituents
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
- C11C1/08—Refining
- C11C1/10—Refining by distillation
- C11C1/103—Refining by distillation after or with the addition of chemicals
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Fats And Perfumes (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses an improved urea inclusion method for enriching polyunsaturated fatty acids, which comprises the steps of mixing solvent, urea and fatty acids (or methyl ester and ethyl ester thereof), directly removing the solvent under vacuum condition to obtain a mixture of urea crystals and fatty acids which are not included by urea, dissolving the fatty acids which are not included by urea by using an organic solvent, and removing and dissolving the fatty acids to obtain a product rich in polyunsaturated fatty acids. The method omits the crystallization step of the traditional urea inclusion method, has high enrichment efficiency on polyunsaturated fatty acids, is wider in applicable solvent types, and has good application prospect.
Description
Technical Field
The invention relates to the technical field of lipid preparation, in particular to an improved urea inclusion method for enriching polyunsaturated fatty acids.
Background
Since the discovery in 1940 of bengen that urea forms stable crystals with aliphatic long-chain compounds, urea inclusion (crystallization) has been discovered to be useful for the enrichment of a variety of polyunsaturated fatty acids and has been widely used in the preparation of different types of high purity fatty acids. The principle is that urea molecules can form stable crystal inclusion compound with saturated fatty acid, monounsaturated fatty acid and the like to be separated out in the crystallization process, and polyunsaturated fatty acid has a certain space configuration due to more double bonds and bent carbon chains and is not easy to be included by urea, so that after urea inclusion treatment, the dissolved lipid component in filtrate is filtered and collected, and the product rich in polyunsaturated fatty acid can be obtained. As known from literature search and finishing, conventional urea inclusion processes generally employ processes comprising the steps of:
(1) Preparation of organic solvent-urea-fatty acid mixed solution: dissolving a certain amount of urea and fatty acid (or methyl ester and ethyl ester thereof) mixture in absolute ethyl alcohol or polar organic solvents such as methanol, 95% ethanol and the like at a certain temperature to form uniform transparent mixed liquid;
(2) Low temperature crystallization and solid-liquid separation: cooling the mixed solution (even below-20deg.C), maintaining for a certain time to perform urea inclusion (or called "low temperature crystallization"), fully combining with saturated fatty acid or low unsaturation fatty acid and urea to form crystal precipitation, and filtering to obtain polyunsaturated fatty acid organic solvent solution;
(3) Post-treatment: concentrating (or not concentrating) the organic solvent solution of polyunsaturated fatty acid, even removing solvent, adding appropriate amount of water (and petroleum ether and other organic solvents), separating liquid, and further dehydrating (and removing solvent) the upper oil layer to obtain the final product.
In the step (1), ethanol is a common polar organic solvent, and in order to ensure that the fatty acid (or methyl ester or ethyl ester thereof) mixture can be dissolved in the organic solvent, it is generally necessary to use ethanol with a concentration of 90% or more, and the higher the concentration of ethanol, the more difficult urea is to be dissolved, and the higher the dissolution temperature is required; in the step (2), the lower the temperature of the low-temperature crystallization, the less urea remains in the organic solvent solution, which is more beneficial to the improvement of the polyunsaturated fatty acid content in the final product, and the low-temperature crystallization generally requires 2 to 48 hours; in the step (3), no matter what temperature and time conditions are used in the low-temperature crystallization stage, part of urea still remains in the polar organic solvent and cannot be separated out, so that the urea is required to be eluted, and therefore, the urea which is removed by the water washing does not actually participate in the inclusion process, and the utilization rate of the urea and the enrichment effect of polyunsaturated fatty acids are reduced to a certain extent. In a word, the traditional urea inclusion method has high concentration requirement on polar organic solvents, long crystallization time, relatively poor urea utilization rate and polyunsaturated fatty acid enrichment effect.
Disclosure of Invention
The invention aims to provide an improved urea inclusion method for enriching polyunsaturated fatty acids, so as to solve the defects of the existing method.
The technical scheme adopted for solving the technical problems is as follows:
an improved urea inclusion process for the enrichment of polyunsaturated fatty acids comprising the steps of:
(1) Uniformly mixing a certain amount of solvent, urea and fatty acid to obtain a uniform mixture;
(2) Evaporating the uniform mixture obtained in the step (1) directly at a temperature of not lower than 50 ℃ under reduced pressure to remove the solvent, thereby obtaining a mixture of urea crystals and fatty acid which is not included by the urea crystals;
(3) Adding a proper amount of organic solvent into the mixture of the urea crystals and the fatty acids which are not included by the urea crystals, which is obtained in the step (2), so as to dissolve the fatty acids which are not included by the urea crystals, and filtering to obtain an organic solvent solution of the fatty acids which are not included by the urea;
(4) And (3) removing the organic solvent from the organic solvent solution of the fatty acid which is not included by the urea and is obtained in the step (3) to obtain a product rich in polyunsaturated fatty acid.
In one embodiment, in the step (1), the mass ratio of urea to fatty acid is 0.3:1-20:1. Preferably, the mass ratio of urea to fatty acid is 18-20:1.
In one embodiment, in the step (1), the solvent includes at least one of ethanol, methanol, or acetone; or the solvent is a mixed solvent of at least one of ethanol, methanol or acetone and water or a nonpolar organic solvent. Specifically, the solvent is preferably any one of absolute ethyl alcohol, absolute methyl alcohol, absolute acetone and the like, or a mixture of two or more polar organic solvents, such as a mixed solution prepared by ethanol-methyl alcohol, ethanol-acetone, methanol-acetone and methanol-ethanol-acetone according to any proportion, or a mixed solvent of the polar organic solvents such as absolute ethyl alcohol, absolute methyl alcohol, absolute acetone and the like and water or a nonpolar organic solvent.
In one embodiment, in the step (1), water may be selected as the solvent.
In one embodiment, in the steps (1) to (2), when water or an organic solvent having a water content of not less than 15% is used as the solvent, the urea liquid and the fatty acid are ensured to be in a uniform mixed state by using a method such as strong stirring (e.g., stirring at a rotation speed of 150rpm or more), ultrasonic assistance, high-speed homogenization (e.g., homogenization at a rotation speed of 500rpm or more), and the like during the process of removing the solvent by evaporation under reduced pressure.
In one embodiment, in the steps (1) to (4), the fatty acid is a mixture containing a certain amount of polyunsaturated fatty acid, and the chemical form of the fatty acid may be free fatty acid, fatty acid methyl ester, fatty acid ethyl ester, and the like.
In one embodiment, in the step (1), the step of uniformly mixing may be that the solvent, urea and fatty acid form a uniform and transparent mixed solution, or that the solvent, urea and fatty acid form a relatively uniform emulsion under the action of external force.
In one embodiment, in the step (3), the organic solvent is preferably a nonpolar organic solvent which cannot dissolve urea, such as petroleum ether, n-hexane, carbon tetrachloride, etc.
In a preferred embodiment, in the step (1), the solvent 94-96% ethanol, urea and fatty acid algae oil ethyl ester are uniformly mixed at 69-71 ℃, and the mass ratio of the 94-96% ethanol, urea and algae oil ethyl ester is 98-102:18-20:1; in the step (2), the solvent is removed by decompression evaporation at 69-71 ℃; in the step (3), the added organic solvent is petroleum ether, and the mass ratio of 94-96% ethanol, urea, algae oil ethyl ester and petroleum ether is 98-102:18-20:1:9-11. At this time, the DHA content in the algae oil ethyl ester can be increased from 41.23% to 96.78% before treatment.
In the step (1), the proportion of the solvent to the urea and the mixing temperature are not limited, and according to the common general knowledge, the lower the solvent consumption is, the smaller the amount of the urea which can be dissolved at the same temperature is, but the too high solvent amount can increase the workload of the reduced pressure evaporation in the step (2) and prolong the evaporation time; the higher the mixing temperature, the more urea can be dissolved under the same solvent amount, but the higher dissolving temperature can lead to the reaction of urea with methanol and ethanol to produce toxic substances such as methyl carbamate, ethyl carbamate and the like.
In the step (1), the solvent has a larger selection range, especially, water can be independently used as the solvent, the water addition in the organic solvent can improve the solubility of urea, quicken the dissolution speed of urea and is beneficial to shortening the process time, but when the urea is coated by water or the organic solvent with high water content, such as 70 percent ethanol, 50 percent ethanol and the like, the fatty acid is difficult to completely dissolve, in order to ensure that the urea can be fully coated with the fatty acid in the decompression evaporation process in the step (2), the solvent-urea-fatty acid can be ensured to form a uniform emulsion by adopting means of high-speed stirring, high-speed homogenization, ultrasonic assistance and the like in the step (1), and the emulsion state of the solvent-urea-fatty acid still needs to be maintained by means of external force effects, such as high-speed stirring, high-speed homogenization and ultrasonic assistance in the decompression evaporation process. In contrast, conventional urea inclusion processes typically use absolute ethanol, absolute methanol, and 95% ethanol as solvents to ensure that both urea and fatty acids dissolve and form a homogeneous solution, with lower urea solubility and slower dissolution.
In the step (2), the solvent is directly removed from the solvent-urea-fatty acid mixture by reduced pressure distillation, so that the urea is crystallized and separated out due to the reduction of the solvent, and after the solvent is completely evaporated, the urea dissolved in the solvent can be completely crystallized, so that all the urea can participate in the inclusion process of the inclusion fatty acid and the low-unsaturation fatty acid, the urea utilization rate and the polyunsaturated fatty acid enrichment efficiency are high, and the crystallization process is rapid and takes a short time; the conventional urea inclusion method generally adopts a temperature reduction method to reduce the solubility of urea in ethanol and methanol so as to crystallize and separate out the urea, but the crystallization method is difficult to completely crystallize the urea dissolved in the solvent, part of the urea is still dissolved in the solvent, and the urea is removed in a water washing mode, so that the utilization rate of the urea and the enrichment efficiency of polyunsaturated fatty acids are lower, and the crystallization process generally needs 6-48 hours to complete.
In the step (3) of the present invention, although polar solvents such as ethanol, t-butanol, isopropanol and the like may be used for dissolving the fatty acid after the urea inclusion treatment, these polar solvents dissolve the fatty acid and at the same time dissolve part of the precipitated urea crystals, so that nonpolar solvents such as petroleum ether, n-hexane, carbon tetrachloride and the like, which do not dissolve urea, are preferable.
The equipment, reagents, processes, parameters, etc. according to the present invention are conventional equipment, reagents, processes, parameters, etc. unless otherwise specified, and are not exemplified.
All ranges recited herein are inclusive of all point values within the range.
In the present invention,% is mass percent and ratio is mass percent unless otherwise specified.
Compared with the background technology, the technical proposal has the following advantages:
the invention has the beneficial effects that the invention provides an improved urea inclusion method for enriching polyunsaturated fatty acids, which is characterized in that solvent, urea and fatty acids are fully mixed and then the solvent is directly removed by reduced pressure distillation, so that the urea completes the inclusion effect in the process of crystal precipitation, then the fatty acids after urea inclusion are dissolved by nonpolar solvent, and then the product rich in polyunsaturated fatty acids is obtained by solvent removal. The method has wide application range to solvents, does not need a long-time low-temperature crystallization process, has higher utilization efficiency of urea and enrichment efficiency of polyunsaturated fatty acids, and has good industrialized application prospect.
Detailed Description
The invention is further illustrated below with reference to examples.
In the following examples and comparative examples, the technical effect was demonstrated by comparing the change in docosahexaenoic acid (DHA) content before and after urea inclusion using Crypthecodinium cohnii oil of ethyl ester type (referred to as ethyl ester of algae oil for short) as an initial raw material, wherein the determination of DHA content was by a peak area normalization method in GB 5009.168-2016 determination of fatty acids in food safety national standard food.
The following examples are used to describe embodiments of the present invention in detail, so that the technical means can be applied to the present invention to solve the technical problems, and the implementation process for achieving the technical effects can be fully understood and implemented accordingly.
Example 1
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of absolute ethyl alcohol at 80 ℃ to form a uniform absolute ethyl alcohol-urea-algae oil ethyl ester mixed solution, then the mixed solution is transferred into a rotary evaporation bottle while being hot, ethanol is removed by reduced pressure rotary evaporation at 80 ℃ to obtain a mixture of algae oil ethyl ester and urea crystals which are not included by urea, then 20 parts of petroleum ether is added to wash and fully dissolve algae oil ethyl ester which is not included by urea, the petroleum ether solution is filtered and collected, and the petroleum ether is removed by reduced pressure evaporation to obtain a product rich in polyunsaturated fatty acids.
Example 2
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of 95% ethanol at 70 ℃ to form a uniform absolute ethanol-urea-algae oil ethyl ester mixed solution, then the mixed solution is transferred into a rotary evaporation bottle while being hot, ethanol is removed by reduced pressure rotary evaporation at 70 ℃ to obtain a mixture of algae oil ethyl ester and urea crystals which are not included by urea, 10 parts of petroleum ether is added to wash and fully dissolve algae oil ethyl ester which is not included by urea, the petroleum ether solution is filtered and collected, and the petroleum ether is removed by reduced pressure evaporation to obtain a product rich in polyunsaturated fatty acids.
Example 3
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of 85% ethanol at 70 ℃ to form a uniform absolute ethanol-urea-algae oil ethyl ester mixed solution, then the mixed solution is transferred into a rotary evaporation bottle while being hot, ethanol is removed by reduced pressure rotary evaporation at 70 ℃ to obtain a mixture of algae oil ethyl ester and urea crystals which are not included by urea, 10 parts of petroleum ether is added to wash and fully dissolve algae oil ethyl ester which is not included by urea, the petroleum ether solution is filtered and collected, and the petroleum ether is removed by reduced pressure evaporation to obtain a product rich in polyunsaturated fatty acids.
Example 4
Weighing 20 parts of urea and 1 part of algae oil ethyl ester, dissolving the mixture in 100 parts of 95% ethanol at 70 ℃ to form a uniform absolute ethanol-urea-algae oil ethyl ester mixed solution, transferring the mixed solution into a rotary evaporation bottle while the mixed solution is hot, removing ethanol by reduced pressure rotary evaporation at the temperature of 70 ℃ to obtain a mixture of algae oil ethyl ester and urea crystals which are not included by urea, adding 10 parts of petroleum ether to wash and fully dissolve algae oil ethyl ester which is not included by urea, filtering and collecting petroleum ether solution, and removing petroleum ether by reduced pressure evaporation to obtain a product rich in polyunsaturated fatty acid.
Example 5
Weighing 0.5 part of urea and 1 part of algae oil ethyl ester, dissolving the urea and 1 part of algae oil ethyl ester in 10 parts of 95% ethanol at 70 ℃ to form a uniform absolute ethanol-urea-algae oil ethyl ester mixed solution, transferring the mixed solution into a rotary evaporation bottle while the mixed solution is hot, removing ethanol by reduced pressure rotary evaporation at 70 ℃ to obtain a mixture of algae oil ethyl ester which is not included by urea and urea crystals, adding 10 parts of petroleum ether to wash and fully dissolve algae oil ethyl ester which is not included by urea, filtering and collecting petroleum ether solution, and obtaining a product rich in polyunsaturated fatty acid after removing petroleum ether by reduced pressure evaporation.
Example 6
Weighing 5 parts of urea and 5 parts of distilled water in a vacuum reaction bottle, then placing the vacuum reaction bottle in a heat-collecting magnetic stirrer, magnetically stirring at 70 ℃ to fully dissolve the urea, then adding 2 parts of algae oil ethyl ester into the urea solution, magnetically stirring at 200rpm for 2min to fully mix the urea solution and the algae oil ethyl ester, then switching on a vacuum pump to continue to keep magnetically stirring, completely evaporating water in the mixture to dryness to obtain a mixture of urea crystals and the algae oil ethyl ester which is not included by the urea, then breaking vacuum, adding 15 parts of n-hexane into the vacuum reaction bottle to fully dissolve the algae oil which is not included by the urea, filtering and collecting the n-hexane solution, and evaporating under reduced pressure to remove the n-hexane to obtain a product rich in polyunsaturated fatty acids.
Example 7
Weighing 5 parts of urea and 10 parts of 50% ethanol in a vacuum reaction bottle, placing the vacuum reaction bottle in a heatable ultrasonic cleaner, fully dissolving the urea by mechanical stirring at 70 ℃, adding 2 parts of algae oil ethyl ester into the vacuum reaction bottle, fully mixing urea solution and algae oil ethyl ester under the ultrasonic action of the stirring rotating speed of 90rpm and 50Hz to form an emulsion, switching on the vacuum reaction bottle to remove solvent, continuously maintaining mechanical stirring and ultrasonic oscillation in the solvent removal process to maintain the emulsion state, obtaining a mixture of urea crystals and algae oil ethyl ester which is not included by urea after the solvent in the vacuum reaction bottle is completely evaporated, breaking vacuum, adding 20 parts of n-hexane into the bottle to dissolve the algae oil ethyl ester which is not included by urea, filtering, and collecting filtrate to evaporate to dryness to obtain a product.
The algae oil ethyl ester is urea coated by adopting a traditional urea coating method, so as to compare the implementation effect of the technical scheme provided by the invention.
Comparative example 1
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of absolute ethyl alcohol at 80 ℃ to form a uniform absolute ethyl alcohol-urea-algae oil ethyl ester mixed solution, then the mixed solution is placed in a water bath at 5 ℃ for heat preservation and crystallization for 12 hours to obtain an ethanol solution of urea crystals and algae oil ethyl ester which is not included by urea, then the ethanol solution is filtered, filtrate is collected, and added with equal volume of water to be fully and uniformly mixed, and then the mixture is left to stand for separation, and algae oil ethyl ester which is not included by urea on the upper layer is collected, and the product is obtained after water washing and dehydration.
Comparative example 2
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of absolute ethyl alcohol at 80 ℃ to form a uniform absolute ethyl alcohol-urea-algae oil ethyl ester mixed solution, then the mixed solution is placed in a refrigerating fluid at-20 ℃ for heat preservation and crystallization for 12 hours to obtain an ethanol solution of urea crystals and algae oil ethyl ester which is not included by urea, then the urea crystals and the algae oil ethyl ester are filtered, filtrate is collected, added with equal volume of water, fully mixed, and then placed, separated, and the algae oil ethyl ester which is not included by urea on the upper layer is collected, washed and dehydrated to obtain the product.
Comparative example 3
1 part of urea and 1 part of algae oil ethyl ester are weighed and dissolved in 10 parts of 95% ethanol at 80 ℃ to form a uniform absolute ethanol-urea-algae oil ethyl ester mixed solution, then the mixed solution is placed in a water bath at 5 ℃ for heat preservation and crystallization for 48 hours to obtain an ethanol solution of urea crystals and algae oil ethyl ester which is not included by urea, then the ethanol solution is filtered, filtrate is collected, and added with equal volume of water to be fully and uniformly mixed, and then the mixture is left to stand for separation, and the algae oil ethyl ester which is not included by urea on the upper layer is collected, washed and dehydrated to obtain the product.
Comparative example 4
Weighing 5 parts of urea and 5 parts of distilled water, magnetically stirring at 70 ℃ to fully dissolve the urea, adding 2 parts of algae oil ethyl ester into the urea solution, homogenizing, placing in a water bath at 5 ℃ for heat preservation and crystallization for 12 hours, filtering, collecting filtrate, adding equal volume of water, fully mixing uniformly, standing, separating liquid, collecting algae oil ethyl ester of which the upper layer is not included by the urea, and washing and dehydrating to obtain the product.
Comparative example 5
Weighing 5 parts of urea and 10 parts of 50% ethanol, magnetically stirring at 70 ℃ to fully dissolve the urea, adding 2 parts of algae oil ethyl ester into the urea solution, homogenizing, placing in a water bath at 5 ℃ for heat preservation and crystallization for 12 hours, filtering, collecting filtrate, adding equal volume of water, fully mixing uniformly, standing, separating liquid, collecting algae oil ethyl ester of which the upper layer is not coated by the urea, and washing and dehydrating to obtain the product.
The products obtained in the above examples and comparative examples were subjected to gas chromatography to determine the DHA content before and after the urea inclusion treatment, and the results are shown in the following table:
table 1 urea inclusion conditions and DHA content of the products of each of the examples and comparative examples
As is clear from the comparison of the results of examples 1 to 3, according to the technical scheme of the invention, under the condition of the same urea-algae oil ethyl ester ratio, the enrichment effect of the water content of 0 to 15 percent on DHA does not have obvious difference when ethanol is taken as a solvent; as is clear from comparison of the results of examples 2, 4 and 5, the ratio of urea to algae oil ethyl ester can have a significant effect on the enrichment effect of DHA under the same solvent (concentration, amount) based on the technical scheme of the present invention.
By comparing comparative example 1 with comparative example 2, it is known that the effect of the conventional urea inclusion method is related to the crystallization temperature, and according to the known art, the effect of the conventional urea inclusion method is also related to the crystallization time.
It is clear from examples 6 and 7 that urea can be sufficiently dissolved but algae oil ethyl ester cannot be dissolved even when 50% ethanol with a high water content is used as a solvent, and that the solvent-urea-algae oil ethyl ester can form an unstable emulsion under the action of mechanical force, and delamination phenomenon is easy to occur after the action of mechanical force is removed. When the solvent is removed, the mechanical force is kept to act on the emulsion, and in the process of continuously removing the solvent, the urea crystals can still realize the inclusion effect on saturated fatty acid and fatty acid with low unsaturation degree, so that polyunsaturated fatty acid in the non-included algae oil ethyl ester can be relatively enriched.
As can be seen from the comparison of the implementation effects of examples 1 and comparative examples 1-2, examples 6 and comparative example 4, and examples 7 and comparative example 5, the DHA enrichment effect obtained by the technical scheme of the invention is obviously superior to that obtained by the traditional urea inclusion method.
The above embodiments are only some of the preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and any person skilled in the art may make modifications or alterations to the above disclosed technical content to equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (10)
1. An improved urea inclusion process for the enrichment of polyunsaturated fatty acids, characterized in that: the method comprises the following steps:
(1) Uniformly mixing a solvent, urea and fatty acid to obtain a uniform mixture;
(2) Evaporating the uniform mixture obtained in the step (1) under reduced pressure at a temperature not lower than 50 ℃ to remove the solvent, thereby obtaining a mixture of urea crystals and fatty acid which is not included by the urea crystals;
(3) Adding an organic solvent into the mixture of the urea crystals and the fatty acids which are not included by the urea crystals obtained in the step (2) to dissolve the fatty acids which are not included by the urea crystals, and filtering to obtain an organic solvent solution of the fatty acids which are not included by the urea;
(4) And (3) removing the organic solvent from the organic solvent solution of the fatty acid which is not included by the urea and is obtained in the step (3) to obtain a product rich in polyunsaturated fatty acid.
2. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (1), the mass ratio of urea to fatty acid is 0.3:1-20:1.
3. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (1), the mass ratio of urea to fatty acid is 18-20:1.
4. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (1), the solvent comprises at least one of ethanol, methanol, or acetone; or the solvent is a mixed solvent of at least one of ethanol, methanol or acetone and water or a nonpolar organic solvent.
5. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (1), the solvent is water.
6. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the steps (1) to (2), when water or an organic solvent with a water content of not less than 15% is used as the solvent, it is necessary to ensure that the urea liquid and the fatty acid are in a uniform mixing state during the solvent removal process by reduced pressure evaporation.
7. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids as claimed in claim 6, wherein: the method for ensuring that the urea liquid and the fatty acid are in a uniform mixing state comprises the steps of adopting strong stirring, ultrasonic assistance or high-speed homogenization.
8. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: the fatty acid is a mixture containing polyunsaturated fatty acid, and the chemical form of the fatty acid is free fatty acid, fatty acid methyl ester or fatty acid ethyl ester.
9. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (3), the organic solvent is a nonpolar organic solvent which can not dissolve urea, and comprises at least one of petroleum ether, normal hexane or carbon tetrachloride.
10. The improved urea inclusion process for the enrichment of polyunsaturated fatty acids according to claim 1, characterized in that: in the step (1), the solvent 94-96% ethanol, urea and fatty acid algae oil ethyl ester are uniformly mixed at 69-71 ℃, and the mass ratio of the 94-96% ethanol, urea and algae oil ethyl ester is 98-102:18-20:1; in the step (2), the solvent is removed by decompression evaporation at 69-71 ℃; in the step (3), the added organic solvent is petroleum ether, and the mass ratio of 94-96% ethanol, urea, algae oil ethyl ester and petroleum ether is 98-102:18-20:1:9-11.
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Citations (4)
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| CN1036008A (en) * | 1988-03-26 | 1989-10-04 | 山东省海洋药物科学研究所 | The method for separating and preparing of timnodonic acid and docosahexenoic acid and ester class thereof |
| JP2000044982A (en) * | 1998-07-27 | 2000-02-15 | Tama Seikagaku Kk | Method for concentrating and separating unsaturated fatty acid alkyl ester |
| CN102746947A (en) * | 2012-07-18 | 2012-10-24 | 福建华尔康生物科技有限公司 | Method for separating and purifying DHA (docosahexaenoic acid) and saturated fatty acid from schizochytrium limacinum oil |
| US20120271061A1 (en) * | 2009-11-05 | 2012-10-25 | Tao Bernard Y | Method of lowering the cloud point of fatty acid esters |
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2023
- 2023-04-18 CN CN202310410945.XA patent/CN116254156A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1036008A (en) * | 1988-03-26 | 1989-10-04 | 山东省海洋药物科学研究所 | The method for separating and preparing of timnodonic acid and docosahexenoic acid and ester class thereof |
| JP2000044982A (en) * | 1998-07-27 | 2000-02-15 | Tama Seikagaku Kk | Method for concentrating and separating unsaturated fatty acid alkyl ester |
| US20120271061A1 (en) * | 2009-11-05 | 2012-10-25 | Tao Bernard Y | Method of lowering the cloud point of fatty acid esters |
| CN102746947A (en) * | 2012-07-18 | 2012-10-24 | 福建华尔康生物科技有限公司 | Method for separating and purifying DHA (docosahexaenoic acid) and saturated fatty acid from schizochytrium limacinum oil |
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