JPH0533988B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing fats and oils containing long-chain highly unsaturated fatty acids. In the present invention, long-chain highly unsaturated fatty acids mean fatty acids having 20 or more carbon atoms and 3 or more double bonds per molecule, and hereinafter referred to as PUFA.
It is abbreviated as [Prior Art] PUFA has recently attracted attention for its physiological activity and pharmacological effects on humans, and active studies have been conducted on the use of PUFA. However, since PUFA has a high boiling point, high vacuum and high temperatures are required to recover it, which increases energy costs, and exposure to high temperatures increases distillation residue due to polymerization, reducing yield. The problem was pointed out that double bond isomerization occurs and a large amount of undesirable isomers are produced. For this reason, it is known as an advantageous method to use lipase to recover PUFA from fats and oils and proceed with the reaction under milder conditions. [Problems to be solved by the invention] However, lipase catalyzes not only the hydrolysis reaction of fats and oils, but also its reverse reaction, the ester synthesis reaction. (Y. Tsujisaka et al, Biochim.
(Biophys. Acta 489 , 415 (1977)) Therefore, simply proceeding with the hydrolysis reaction using lipase does not allow the reaction to proceed efficiently. This tendency is particularly strong in systems with little water. In view of the above-mentioned problems, an object of the present invention is to provide a process that utilizes a hydrolysis reaction to efficiently produce fats and oils containing a high concentration of PUFA. [Means for solving the problems] The method for producing PUFA-containing fats and oils of the present invention includes
When adding lipase to fats and oils containing PUFA and causing a reaction, a monohydric alcohol is added to proceed with an esterification reaction between fatty acids other than PUFA released by hydrolysis and the added monohydric alcohol,
It is characterized by obtaining oils and fats containing a high concentration of PUFA. [Function] The PUFA-containing fats and oils used in the present invention include, for example, fish fat, whale fat, krill oil, marine chlorella oil, etc., but mixed oils, conjugated isomerized oils, partially hydrogenated oils, etc. containing these fats and oils may also be used. can also be used. It is preferable that the above fats and oils contain 10% or more of EPA (eicosapentaenoic acid) and 3% or more of DHA (docosahexaenoic acid). In the present invention, the lipase used as oxygen for oil and fat hydrolysis is Aspergillus (Asper-
gillus), Rhizopus, Mucor, Penicillium,
Filamentous fungal lipase such as Geotricum, Chromobacterium
In addition to lipases of microbial origin, such as bacterial lipases of the genus Pseudomonas, yeast lipases of the genus Candida, pancreatin lipase of animal origin, etc. can also be used. The hydrolysis conditions may be carried out according to known methods, but the amount of the lipolytic enzyme used is expressed as U (unit), which represents the fat and oil hydrolyzing activity, and the reaction substrate (oil)
50~3000U per 1g, preferably 100~
It is 3000U. The amount of water added is preferably 0.1 to 20% (by weight, the same applies hereinafter), more preferably 1 to 10%, based on the fat or oil. The pH of water is preferably in the range of 4.5 to 8.5, and it is more effective to use a buffer to adjust the pH, with a particularly desirable pH range of 5.5 to 8.0. Furthermore, for a more effective reaction,
Emulsifiers such as polyvinyl alcohol and fatty acid esters can also be used, and addition of bile salts is also effective in increasing hydrolysis activity. The hydrolysis reaction may be carried out in the atmosphere, but
When containing large amounts of long-chain highly unsaturated acids, such as fish oil and whale oil, placing them under an inert gas atmosphere, such as nitrogen gas or carbon dioxide gas, not only prevents deterioration of fatty acids but also deactivates enzymes. can also be prevented. Also, antioxidants, such as tocopherols,
TBHQ, BHA, and BHT may be used together. The hydrolysis reaction is preferably carried out at 20-60°C. Below 20°C, the reaction is slow, and above 60°C, the enzyme is inactivated. It is more preferable to carry out the reaction at a temperature of 30 to 45°C. Although it is preferable to stir the reaction, the reaction can also be carried out in an emulsified state and allowed to stand still. Further, the reaction may be a single-stage reaction, but may also be a multi-stage reaction in order to proceed more efficiently and quickly. An immobilized enzyme column can also be used for continuous reaction. The monohydric alcohol added during hydrolysis in the method of the present invention is an aliphatic alcohol having 1 to 28 carbon atoms, such as methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, dodecanol, hexadecanol, Examples include octadecanol, tetracosanol, hexacodanol, etc., and particularly preferred are butanol, octanol, decanol, dodecanol, hexadecanol, octadecanol, etc. The amount of alcohol used above is per 1 mole of fat or oil,
It is usually 0.1 to 20 mol, preferably 0.1 to 10 mol. Furthermore, in the present invention, an inert organic solvent can be added to carry out the hydrolysis reaction, and the amount used is at most 10 times, preferably at most 3 times, the amount of fat and oil. In the method for producing fats and oils of the present invention, it is preferable to add the monohydric alcohol from the beginning of the reaction, but
Depending on the reaction, the entire amount may not be added at once, but may be added in portions several times, or a method of continuously feeding into the system may also be used. [Effects of the Invention] The method for producing fats and oils of the present invention uses hydrolysis using lipase and adds a monohydric alcohol during the hydrolysis, so fatty acids other than PUFA released by the hydrolysis and the added monohydric alcohol The esterification reaction with PUFA proceeds, making it possible to effectively obtain fats and oils containing a high concentration of PUFA. [Examples] The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples. Example 1 Fish oil (IV=178.9, EPA 16.8%, DHA 8%)
Add 200,000 U of Rhizopus derma together with 5 g of water to 500 g, and stir and hydrolyze in 500 g of hexane at 35°C for 1 hour. Then, 100 g of decyl alcohol is added and hydrolysis is continued while dehydrating.
The reaction was completed after 24 hours and a reaction product was obtained. From this product, triglycerides were fractionated by column chromatography, and the fatty acid composition was methyl esterified and analyzed by GLC. As a result, EPA was 28.0% and DHA was 17.5%.
It was %. Example 2 Fish oil 100g (IV 178.9, EPA 16.8%, DHA 8
%) and 40,000 U of lipase originating from the genus Candeida.
g of ion-exchanged water, and add hexane to this.
Add 500g and 10g of butyl alcohol and carry out the hydrolysis reaction while dehydrating. The reaction was stopped after 24 hours, and the oil layer was separated from the reaction composition by centrifugation. From this oil layer, triglycerides were fractionated by column chromatography, and the fatty acid composition was methyl esterified and analyzed by GLC. As a result, EPA was 28.8%.
It can be seen that DHA is 8.2%, indicating that it is concentrated. Comparative Example 1 Hydrolysis was carried out for 24 hours in the same manner as in Example 1 except that decyl alcohol was not added. Triglycerides were fractionated and analyzed from this reaction product using column chromatography, and the content was 17.5% EPA, DHA.
It was 10%. Comparative Example 2 Hydrolysis was carried out for 24 hours in the same manner as in Example 2 except that petit alcohol was not added. Triglycerides were fractionated from this reaction product using column chromatography, and analysis revealed that EPA was 19.5%.
DHA was 12.0%. Table 1 shows the fatty acid composition of the triglycerides obtained in the above Examples and Comparative Examples. Comparing Example 1 and Comparative Example 1, lipase is
Hydrolysis is promoted by acting on fatty acids other than PUFA, but in Example 1, when alcohol is added, the fatty acids released as a result of hydrolysis are immediately converted into alcohol esters by the action of lipase.
Since this is an ester that is difficult for lipase to decompose, once it is released, the fatty acid cannot form glyceride again. As a result, the concentration of PUFA-containing triglyceride increased, indicating that the reaction was progressing efficiently. On the other hand, in Comparative Example 1, since no alcohol was added, re-esterification progressed and the concentration of PUFA-containing triglyceride was lower than in Example 1.

[Table] In fatty acid display, the first number indicates the number of carbon atoms and the second number indicates the number of unsaturated bonds.
ω (omega) is a number that indicates where the first double bond is located, counting from the terminal methyl group.
Therefore, for example, C20:5ω3 indicates a fatty acid with 20 carbon atoms and five double bonds, of which the first double bond is the third fatty acid counting from the terminal methyl group.

Claims (1)

[Claims] 1. When reacting fats and oils containing long-chain highly unsaturated fatty acids with lipase, monohydric alcohol is added,
An oil or fat characterized by proceeding with an esterification reaction between a fatty acid other than the long-chain polyunsaturated fatty acid liberated by hydrolysis and an added monohydric alcohol to obtain an oil or fat containing a high concentration of long-chain polyunsaturated fatty acids. Production method.