JPH0860181A - Highly unsaturated fatty acid-containing oil and fat - Google Patents

Abstract

PURPOSE: To obtain the oils and fats effecitive for preventing and treating geriatric diseases having high diglyceride and monoglyceride contents and excellent digestion and absorption, containing docosahexaenoic acid in high concentration among constituent fatty acids of oils and fats. CONSTITUTION: A reaction solution comprising 0.05 M tris-hydrochloric acid buffer solution (pH 8.2), 0.2 M calcium chloride and 5% gum arabic is mixed with a lipase derived from Candida lipolytica and a fish oil collected from a head part of tuna, stirred at 45 deg.C for 15 hours and hydrolyzed while adjusting to pH 8.2 with 2 N NaOH. The formed decomposition oil is extracted with hexane and the extracted solution is stirred with acetone and then with 0.3 N sodium hydroxide solution at room temperature for 1 hour to provide the objective highly unsaturated fatty acid-containing fats and oils effective for preventing and treating geriatric diseases containing >=60% docosahexaenoic acid(DHA) among constituent fatty acids of fats and oils and >=80% based on fats and oils of total amount of diglyceride and monoglyceride.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to natural fats and oils containing docosahexaenoic acid (hereinafter abbreviated as DHA) in a high concentration.

[0002]

2. Description of the Related Art Natural fats and oils which are glycerides containing ω3 polyunsaturated fatty acids are often contained in fish oils in the form of triglycerides. In particular, DHA is known to have useful physiological activities such as learning function improvement, anti-arteriosclerotic property, anti-tumor property, immunostimulation and anti-allergy. This DHA
In natural fats and oils that are naturally occurring glycerides, at most 20 to 30% of the constituent fatty acids, and in addition to this, a large amount of saturated fatty acids such as palmitic acid and stearic acid, and ω6 represented by linoleic acid. Since it contains a system polyunsaturated fatty acid, it is inconvenient in terms of excess lipid when this natural fat is used as a health food or a medicine. Because of this, D
Fats and oils with reduced fatty acids other than HA were prepared by an enzymatic method (Yukihisa Tanaka et a.
l, Journal of American Oil
Chemical Society, 69, (199
2) 1210-1214).

A report on high-concentration DHA oils and fats prepared by utilizing a lipase synthesis reaction using free high-purity DHA and glycerin as raw materials and a transesterification reaction of lipase with high-purity DHA ethyl ester (Tanaka Yukihisa et al., Oil Chemistry, Vol. 41, 1992, pp. 563-567 and JP-A-5-331105).

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As reported above, in the prior art, even fats and oils obtained by the optimum selective hydrolysis reaction of fatty acid species using lipase have a DHA content in the constituent fatty acids. It was 53%, 75% of the glyceride was triglyceride, 24% was diglyceride, and 1% was monoglyceride. The fats and oils prepared by the lipase synthesis reaction and transesterification reaction were composed of triglycerides. In general, triglyceride ingested as food is hydrolyzed into free fatty acid and monoglyceride via diglyceride by the action of lipase, which is a digestive enzyme secreted by the pancreas, and the decomposed monoglyceride and free fatty acid are bile. It is known that it forms micelles with acid salts and is absorbed. However, since fats and oils composed of triglycerides do not have hydrophilic residues in the molecule, it is necessary to use a high-concentration dispersant or an operation such as ultrasonic treatment in order to disperse them in an aqueous system. In view of the above points,
An object of the present invention is to provide a natural fat or oil which has good dispersibility in water and good absorbability.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that natural fats and oils containing a high concentration of DHA and having a low saturated fatty acid content are natural fats and oils that can achieve the object. Succeeding in obtaining fats and oils, the present invention has been completed.

That is, the present invention contains 60% or more of DHA among fatty acids constituting fats and oils and is composed of triglycerides, diglycerides and monoglycerides, and the total amount of diglycerides and monoglycerides is 80% or more of fats and oils, or triglycerides. The present invention relates to natural fats and oils characterized in that the ratio of diglyceride in glycerides other than is 70% or more. Hereinafter, the present invention will be described in more detail.

The term "natural fats and oils" as used in the present invention means naturally occurring fatty acid glycerin esters or fatty acid glycerin esters obtained by enzymatically decomposing naturally occurring fatty acid glycerin esters. High concentration DH obtained by the present invention
As a raw material for A-containing fats and oils, fish oil rich in DHA,
Marine-derived natural fats and oils such as whale oil and natural fats and oils derived from microorganisms can be used. It is only necessary to selectively hydrolyze general fatty acids other than DHA by utilizing the specificity of these fats and oils for fatty acid species, but an enzyme suitable for hydrolysis has a low substrate specificity for DHA. Lipase, especially Candida Cyrindrace and Candida
Enzymes from lipolytica are preferred.

Even when an enzymatic reaction is carried out with the above-mentioned enzyme,
According to the conventional method of using only water in addition to the oil and fat as a substrate, it is impossible to obtain a natural oil and fat containing DHA in a high concentration of 60% or more and having the composition defined in the present invention. In the present invention, the desired natural fat or oil could be obtained by adding the water-soluble polymer compound to the reaction system when carrying out the lipase reaction.

The water-soluble polymer compound added to the lipase reaction system may be of a nature that does not inhibit the lipase reaction, and may be a naturally-occurring polymer compound or a synthetic polymer compound. Examples of naturally-derived water-soluble polymer compounds include soluble starch, dextrin, dextran, pectin, gum arabic, natural polymer saccharide compounds such as xanthan gum, gelatin, amino acid polymer compounds such as corn protein-derived peptides, and carboxymethyl cellulose. A cellulose derivative or the like can be used. Polyvinyl alcohol or the like can be used as the synthetic polymer compound. The concentration of these water-soluble polymer compounds added to the reaction system of lipase varies depending on the concentration of fats and oils used, but in the case of compounds such as carboxymethylcellulase, catalan, pectin and xanthan gum, the concentration is 0.1 to 5%. It can be used in the range, preferably 0.5 to 2%, and in compounds such as gelatin, corn-derived peptide, soluble starch, dextran and gum arabic, it can be used in the range of 1 to 20%, preferably 2 to 5%. is there.

The above-mentioned enzyme-hydrolyzing reaction is carried out in the presence of a sufficient amount of water for expressing the activity of the enzyme, and the amount thereof is 1 to 300% with respect to the oil and fat, preferably 40.
It is about 100%. The amount of the enzyme used depends on the concentration of highly unsaturated fatty acid contained in the substrate, the reaction temperature, the reaction p
H, 10 depending on 1g of fats and oils, depending on the reaction time
To 1000 units (U), preferably 50 to 3
It is about 00 units (U). The reaction temperature can be appropriately selected within a range (20 to 60 ° C.) in which lipase is not inactivated, and particularly preferably 25 to 40 ° C.

A buffer solution may be used instead of water in order to keep the pH constant in the hydrolysis reaction. p
H can react in the range of 7 to 9, but particularly preferably 7.
It is 5 to 8.5. Furthermore, in order to accelerate the hydrolysis reaction, divalent metal ions such as calcium and magnesium may be added to the reaction solution. The concentration is 10-500m
It can be used in the range of M, but particularly preferably 150 to 25
0 mM calcium ion is used. The enzymatic reaction proceeds well in the presence of air, but in general, highly unsaturated fatty acids are easily oxidized, so use an inert gas such as nitrogen or argon gas to perform the reaction in an environment where oxygen is limited. It is preferable to carry out.

The hydrolysis rate of fats and oils can be determined by a method of titrating free fatty acids with an alkali or by a method such as gas chromatography. However, the total amount of fatty acid species and the amount of fatty acid species can be separated and quantified at the same time. Chromatography is advantageous in terms of measurement accuracy. The hydrolysis was determined by the following formula.

[Equation 1] The hydrolysis rate may be controlled so as to fall within the range of 60 to 80%, preferably 65 to 75%.

When the above enzyme is used and an enzymatic reaction is carried out, a water-soluble polymer compound is added to the reaction system to hardly hydrolyze the highly unsaturated fatty acid ester contained in the highly unsaturated fatty acid-containing oil or fat. Or, even if it is hydrolyzed, the degree is extremely low, so fatty acids other than highly unsaturated fatty acids are preferentially hydrolyzed, so if this is removed and the undegraded residual glyceride is separated and recovered,
It is possible to obtain a diglyceride containing a highly unsaturated fatty acid, especially DHA at a high concentration, or an oil or fat containing a monoglyceride as a main component. In order to collect the glyceride (natural oil and fat) fraction from the hydrolyzed oil by the above lipase, the usual methods such as alkali deoxidation method, steam distillation method, fractionation by ion exchange resin, molecular distillation, adsorption chromatography, etc. Can be used, and the method is not particularly limited.

[0014]

Industrial Applicability The natural fats and oils of the present invention are excellent in digestion and absorption because they contain DHA in a high concentration and have diglyceride and monoglyceride as the main components, and the saturated fatty acid content is extremely low, resulting in excess energy. It has few problems of ingestion, has good dispersibility when used in an aqueous system, and easily develops useful physiological activity of DHA, and is effectively used for prevention and treatment of adult diseases.

[0015]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. (Example 1) 0.05 M Tris-HCl buffer (pH 8.
2) Dissolve 12,500 units of Candida lipolytica-derived lipase (manufactured by Amano Pharmaceutical Co., Ltd.) in 100 ml of a reaction solution composed of 0.2 M calcium chloride and 5% gum arabic, and collect from the head of tuna. 45g of mixed fish oil A (fatty acid composition is shown in Table 1)
Stir at room temperature for 15 hours and p-p continuously with 2N sodium hydroxide.
Hydrolysis reaction was performed while adjusting H to 8.2 to obtain decomposed oil. The oil and fat was extracted with 100 ml of hexane, and after centrifugation (3,000 rotations, 10 minutes), the hexane layer was collected. Add 40 ml of acetone to this extract, then 20m
l 0.3N sodium hydroxide solution was added, and the mixture was stirred at room temperature for 1 hour. The glyceride from which the free fatty acid was removed could be recovered in the hexane layer, and the weight of the solvent distilled off under reduced pressure was 2.3 g. This product was saponified with an alkali, converted into a methyl ester derivative, and the fatty acid composition was measured by gas chromatography. The measurement results are shown in Table 1. The DHA content in fatty acid was 63.9%.

(Example 2) The fish oil A shown in Example 1 was changed to another raw material, fish oil B (fatty acid composition is shown in Table 2), and the other conditions were the same and the enzymatic reaction, extraction and purification were carried out. Finally, 3.4 g of glyceride was obtained. The fatty acid composition is shown in Table 2. This product was saponified with an alkali, converted into a methyl ester derivative, and the fatty acid composition was measured by gas chromatography. The measurement results are shown in Table 1. The DHA content in fatty acids was 63.2%.

[0017]

[Table 1]

[0018]

[Table 2]

(Example 3) 1 g of the oil / fat obtained in Example 1
5 ml of chloroform: acetone (95: 4, v / v)
The solution was dissolved in, and applied to a silica gel column suspended and packed in a mixed solvent of the same composition, and eluted with the mixed solvent of the same composition. Each glyceride was detected by thin layer chromatography to obtain a fraction containing triglyceride and diglyceride (200 ml). Then, the solvent was distilled off from this fraction under reduced pressure to obtain 0.78 g of oil and fat. With respect to the fats and oils obtained in Example 2 and Example 3, the glyceride composition was measured using an iatroscan. The results are shown in Table 3.

[0020]

[Table 3]

Further, 0.2 g of each of the fats and oils and fish oil B obtained in Examples 2 and 3 was added to 2 ml of purified water and treated with a homogenizer (0 ° C., 6000 rpm) for 5 minutes. The treated oil / fat dispersion was allowed to stand at 4 ° C. for 20 hours, and its state change was observed. The results are shown in Table 4.

[0022]

[Table 4] -: Oil and fat completely separated into two layers +++: Completely dispersed state but not separated into two layers ++: Dispersed state is good, but partly slightly separated state

The fats and oils obtained in Examples 2 and 3 were allowed to stand at 35 ° C. for 2 weeks under the conditions shown in Table 5, and then the fats and oils were analyzed using an ear troscan. The results are shown in Table 6. The fats and oils obtained in Example 3 were stable both in an aqueous solution and in the state of fats and oils, but in the fats and oils obtained in Example 2, monoglycerides were slightly decomposed only in an aqueous solution state.

[0024]

[Table 5] * Both A and D used closed containers and the gas phase was replaced with nitrogen.

[0025]

[Table 6]

Claims (2)

[Claims] 1. A natural fat or oil containing 60% or more of docosahexaenoic acid (DHA) among the constituent fatty acids of fats and oils and having a total amount of diglycerides and monoglycerides of 80% or more of the fats and oils. 2. A natural fat or oil containing docosahexaenoic acid (DHA) in an amount of 60% or more of the constituent fatty acids of the fat and oil and having a diglyceride ratio in glycerides other than triglycerides of 70% or more.