JPH0433838B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for concentrating and separating highly unsaturated fatty acid lower alcohol esters (hereinafter referred to as HUFA) contained therein from fatty acid lower alcohol esters. Conventionally, highly unsaturated fatty acids contained in animal and vegetable oils, especially fish oil, have been added to fish as essential lipids in the form of compounded feed, etc.
Recently, its physiological activity and pharmacological effects on humans have been elucidated, and its usefulness has been confirmed. However, regarding the concentration and separation of HUFA,
A method for esterifying fish oil or fats from marine organisms and concentrating and separating it as a raw material on an industrial scale has not yet been established. As a conventional fractionation technology using fatty acid esters
(1) Natural fractionation method, (2) Molecular distillation method, (3) Solvent fractionation method, (4)
Examples include urea addition method. However, although method (1) has the advantage of being low cost, it is difficult to use for oils and fats with low melting points such as HUFA, and furthermore, it takes a long time to crystallize, and the yield is not high. Method (2) is difficult to use for materials with many double bonds, such as HUFA, as polymerization and isomerization tend to occur. Compared to method (1), method (3) allows easier crystallization, has a lower liquid viscosity, has better filtration efficiency, and has a higher yield. But at high concentrations
Obtaining HUFA requires low temperatures, which increases running costs. Method (4) is superior to methods (1), (2), and (3), as it allows HUFA to be obtained at a higher concentration. However, it requires large amounts of solvents such as urea and methanol, and HUFA is removed from the reaction solution.
is not easy to recover. The present inventors conducted research to improve these shortcomings, and found that HUFA was produced using a specific lipase.
We have invented an industrially advantageous method for easily obtaining . The present invention involves selectively hydrolyzing fatty acid lower alcohol esters by utilizing the substrate specificity of lipase obtained from any of the genus Rhizopus, Espergillus, and Mucor, and then removing the decomposed fatty acids. The present invention provides a method for concentrating and separating characteristic HUFA. The highly unsaturated fatty acids of HUFA in the present invention are:
Among long-chain fatty acids with 20 or more carbon atoms and 3 or more double bonds per molecule, ω that has physiological activity.
-3 acid (omega-3 acid, ω-3 is a fatty acid whose double bond is located third from the terminal methyl group) and ω
It mainly targets -6 acids (omega-6 acids, where the fatty acid double bond is located at the 6th position from the terminal methyl group), and both of these have great significance in the body. It has high physiological activity. Such fatty acids include C20:3ω-3 (eicosatrienoic acid), C20:4ω-3 (eicosatetraenoic acid), C20:5ω-3 (eicosapentaenoic acid),
C22:5ω-3 (docosapentaenoic acid), C22:6ω-
omega-3 acids such as 3 (docosahexaenoic acid),
C20:3ω-6 (eicosatrienoic acid), C20:4ω-
6 (eicosatetraenoic acid or arachidonic acid),
C22:3ω-6 (docosatrienoic acid), C22:4ω-6
(docosatetraenoic acid), C22:5ω-6 (docosapentaenoic acid), and C22:4ω-6 (tetracosatetraenoic acid), where the double bond is shown in the cis position. It is something. The fatty acid lower alcohol ester used in the method of the present invention is a mixture of fats and oils containing highly unsaturated fatty acids or fatty acids, methanol, ethanol, propanol,
An ester synthesized with a lower alcohol such as butanol, preferably an ester with methanol or ethanol. Specific examples include fatty acid ethyl esters obtained by transesterifying various animal and vegetable oils, including marine animal oils such as fish oil and cod liver oil, with ethanol in the presence of a catalyst. In the present invention, the substrate specificity of lipase is
Normal fatty acid lower alcohol esters are decomposed by lipase, but HUFA refers to the property that it is difficult to be decomposed by lipase. The lipase used in the present invention is a lipase of microbial origin, such as one originating from the genus Rhizopus, one originating from the genus Aspergillus, and one originating from the genus Mucor. In the present invention, the temperature and PH during hydrolysis of fatty acid lower alcohol ester may be set to those suitable for the lipase, and buffers and emulsifiers may or may not be used, but if an emulsifier is used, hydrolysis It is not easy to separate the substance from the lipase solution.
An appropriate amount of lipase may be used depending on its activity, and the lipase solution can be reused. The amount of lipase solution should be about the same amount as the fatty acid lower alcohol ester, and it is sufficient if uniform emulsification can be achieved. Recovery of HUFA after hydrolysis can be performed in accordance with a general method for deoxidizing fats and oils. That is, the hydrolyzed solution is separated into a lipase solution and oil by centrifugation, the oil, which is a mixture of HUFA and fatty acids, is neutralized by adding an alkaline aqueous solution, the fatty acids are made into soap, and the HUFA and soap water are separated by centrifugation. Can be separated. According to the method of the present invention, unlike conventional methods,
There is no need to use a solvent, the reaction temperature is around 40°C, and no polymerization or isomerization occurs. Moreover, HUFA can be concentrated and separated with simple operations. Next, examples of the present invention will be described. Example 1 Fatty acid ethyl ester was obtained by reacting small fish oil such as sardine and mackerel with ethanol using sodium methylate as a catalyst. The fatty acid composition was as shown in Table-1. 100g of this fatty acid ethyl ester was placed in a reactor, 100g of ion-exchanged water containing 30,000 units of lipase originating from the genus Rhizopus (Tanabe Seiyaku Co., Ltd., product) was added under a nitrogen stream, and the mixture was hydrolyzed with stirring at 40°C for 12 hours. I let it happen. After the reaction, oil was obtained by centrifugation. The acid value of the obtained oil was 74.5. This oil was neutralized with an aqueous solution of caustic soda, and the soap water was removed by centrifugation to obtain 52 g of HUFA. The fatty acid composition of this HUFA was as shown in Table-1. From the results in Table 1, especially when C20:5ω-3
It can be seen that the C22:6ω-3 component increases significantly.
(The same applies to the effects of the following examples.) Example 2 The fatty acid ethyl ester of Example-1 was converted to Example-
As in step 1, 50,000 units of lipase originating from the Aspergillus genus (manufactured by Amano Pharmaceutical Co., Ltd.) was used at 40°C.
Hydrolyzed for 24 hours. The acid value at that time was 50.7
62g of HUFA after neutralization and centrifugation
I got it. The fatty acid composition of this HUFA was as shown in Table-1. Example 3 Fatty acid methyl ester obtained from the same small fish oil as in Example-1 was prepared in the same manner as in Example-1.
Unit's lipase of Mucor origin (Amano Pharmaceutical Co., Ltd.)
Co., Ltd., products) for 24 hours at 30°C.
The acid value at that time was 98.8, and 44.5 g of HUFA was obtained after neutralization and centrifugation. The fatty acid composition of this HUFA was as shown in Table-1.

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Claims (1)

[Scope of Claims] 1. A fatty acid lower alcohol ester is selectively hydrolyzed using the substrate specificity of lipase obtained from any of Rhizopus, Aspergillus, and Mucor, and then the decomposed fatty acid is A method for concentrating and separating highly unsaturated fatty acid lower alcohol esters, the method comprising: removing lower alcohol esters of highly unsaturated fatty acids; 2. The method according to claim 1, wherein the highly unsaturated fatty acid of the highly unsaturated fatty acid lower alcohol ester has 20 or more carbon atoms and 3 or more double bonds.