JP6645804B2 - Manufacturing method of structural fats and oils - Google Patents

Description

  The present invention relates to a method for producing a structured fat or oil having a high proportion of ω3-based polyunsaturated fatty acids bonded to positions 1 and 3 of glycerol rather than position 2.

  Structural fats (also referred to as structural lipids) are molecular fats and oils in which specific fatty acids are incorporated at specific positions in glycerin for the purpose of improving nutrition, improving physical properties, or replacing natural fats and oils. For example, in fish oil, a large amount of polyunsaturated fatty acid is distributed at the position of sn-2 of glycerol, whereas a large amount of n-3 long-chain polyunsaturated fatty acid is distributed at the first and / or third position of the glyceride structure. Fats and oils having triglyceride in which less than 40 mol% of the total amount of n-3 long-chain polyunsaturated fatty acids are bonded to the 2-position of glyceride, which has an effect of reducing blood lipid concentration (Patent Document 1) ) Etc. have been proposed.

  In Patent Document 1, triolein and a hydrolyzed fatty acid concentrate of fish oil are transesterified using a lipase having 1,3-position specificity, and the fatty acid at sn-1,3 position of glyceride is highly unsaturated with ω3 system. It is converted to fatty acids. However, according to this method, it is difficult to separate the unreacted ω3 polyunsaturated fatty acid from the fatty acid released from the glyceride, and the loss of the ω3 polyunsaturated fatty acid increases the cost.

On the other hand, a method has also been proposed in which a ω3-based highly unsaturated fatty acid is bonded to sn-1,3 positions of glycerol by an esterification reaction instead of a transesterification reaction. For example, glycerin and a DHA-containing fatty acid in the presence of a lipase that specifically or preferentially acts on the 1,3-position of triacylglycerol and has a lower activity on docosahexaenoic acid (C22: 6, DHA) than other fatty acids. First, fatty acids other than DHA are preferentially bound to the 1,3-positions of glycerin to produce 1,3-diacylglycerol, which is then esterified to the 1- or 3-position. Fatty acid other than DHA is acyl-transferred to the 2-position of acyl glycerol to become 1,2-diacyl glycerol or 3,2-diacyl glycerol, and finally, 1 or 3 of the diacyl glycerol after acyl transfer. Is bound to the DHA concentrated in the free fatty acid fraction, so that the DHA bound to the 2-position of triacylglycerol How the content of DHA attached to the 1,3-position of the triacylglycerols to produce a high triacylglycerol (Patent Document 2) it has been reported.
The esterification reaction is superior to the transesterification reaction in that the unreacted ω3-based highly unsaturated fatty acid can be easily reused.

JP-A-9-13075 JP 2008-278781 A

However, the method of Patent Document 2 has a problem that a large amount of diacylglycerol tends to remain in the esterification reaction oil. Further, in practice, it was considered that transfer of the acyl group from 1,3-diacylglycerol to 1 (3), 2-diacylglycerol was difficult to proceed, and it was considered difficult to efficiently achieve a desired DHA concentration.
Therefore, the present invention relates to providing a new method for producing a structured fat or oil having a high ratio of the ω3-based polyunsaturated fatty acid bonded to the 1,3-position of glycerol while suppressing the production of diacylglycerol.

  The present inventors have conducted intensive studies in view of the above problems, and found that a partially hydrolyzed oil obtained by partially hydrolyzing an oil or fat using a 1,3-position selective lipase and a predetermined acid value (AV ) With an ω3-based highly unsaturated fatty acid having a 1,3-selective lipase to suppress the by-product of diacylglycerol and to bind to the 1,3-position of glycerol. It has been found that structural fats and oils having a high ratio of ω3-based highly unsaturated fatty acids can be easily obtained.

  That is, the present invention relates to a method for producing a structural fat or oil in which 75% by mass or more of the ω3-based polyunsaturated fatty acid in the constituent fatty acids is bonded to the 1,3-position of glycerol, using a 1,3-position-selective lipase. A partially hydrolyzed oil obtained by partially hydrolyzing fats and oils, containing 1,2-diacylglycerol in 65% by mass or more in diacylglycerol, and a ω3-highly unsaturated fatty acid, and having an acid value of 125 to 180 mgKOH / g. Which comprises a step of subjecting a fatty acid as described above to an esterification reaction using a 1,3-position-selective lipase.

  ADVANTAGE OF THE INVENTION According to this invention, the structure fats and oils which contain the high ratio of (omega) 3 highly unsaturated fatty acid couple | bonded with the 1-, 3-position of glycerol, and contain triacylglycerol in high concentration are obtained easily. In the method of the present invention, unreacted ω3-based polyunsaturated fatty acids can be easily recovered from the esterification reaction oil by distillation, and the concentration of ω3-based polyunsaturated fatty acids in the distillation fraction is high, so It can be effectively reused as a raw material fatty acid without losing fatty acids.

In the method of the present invention for producing a structured fat / oil in which 75% by mass or more of the ω3-based polyunsaturated fatty acid in the constituent fatty acids is bonded to the 1,3-position of glycerol, the fat / oil is partially hydrolyzed using a 1,3-position-selective lipase. And a partially hydrolyzed oil containing 1,2-diacylglycerol in an amount of 65% by mass or more in diacylglycerol, and a fatty acid containing an ω3 highly unsaturated fatty acid and having an acid value of 125 to 180 mgKOH / g. Is subjected to an esterification reaction using 1,3-position selective lipase.
In the present specification, “oil” and “oil / fat” have the same meaning, and substances constituting oil (oil / fat) include not only triacylglycerol but also monoacylglycerol and diacylglycerol. That is, in the present invention, the oil (oil or fat) contains any one or more of monoacylglycerol, diacylglycerol and triacylglycerol.
In the present specification, the ω3 polyunsaturated fatty acid is a long-chain fatty acid having 18 or more, preferably 20 or more carbon atoms, and having 3 or more, preferably 5 or more unsaturated bonds. The ω3-based highly unsaturated fatty acids are preferably eicosapentaenoic acid (C20: 5, EPA) and docosahexaenoic acid (C22: 6, DHA).

[1,3-position selective lipase]
The 1,3-position selective lipase used in the present invention is a lipase showing specificity at the sn-1 and sn-3 positions of triacylglycerol. The 1,3-position-selective lipase is not particularly limited, and lipases derived from animals, plants, and microorganisms can be used. For example, genus Rhizopus, Aspergillus, Mucor, Lipases originating from the genus Rhizomucor, the genus Pseudomonas, the genus Geotrichum, the genus Penicillium, the genus Candida and the like can be mentioned.
As the 1,3-position selective lipase, it is preferable to use an immobilized lipase in which the lipase is immobilized on a carrier, from the viewpoint of effective use of lipase activity and cost. Examples of the immobilized lipase include Lipozyme RM IM, manufactured by Novozyme Japan.

  Immobilized carriers include Celite, diatomaceous earth, kaolinite, silica gel, molecular sieves, porous glass, activated carbon, calcium carbonate, inorganic carriers such as ceramics, ceramic powder, polyvinyl alcohol, polypropylene, chitosan, ion exchange resin, hydrophobic adsorption Organic polymers such as resins, chelate resins, and synthetic adsorption resins are exemplified. Above all, ion exchange resins are preferred because of their high water retention. In addition, among the ion-exchange resins, it is preferable that the ion-exchange resin is porous from the viewpoint that the amount of enzyme adsorbed can be increased by having a large surface area.

The particle size of the resin used as the immobilization carrier is preferably 50 to 2000 μm, more preferably 100 to 1000 μm. The pore diameter is preferably from 10 to 150 nm, more preferably from 10 to 100 nm. Examples of the material include phenol formaldehyde-based, polystyrene-based, acrylamide-based, and divinylbenzene-based resins, and a phenol formaldehyde-based resin (for example, Duolite A-568 manufactured by Rohm and Haas) is preferable from the viewpoint of improving lipase adsorption.
At this time, the mass of the lipase to be used is preferably 10 to 300%, more preferably 20 to 250%, further preferably 30 to 200% with respect to the mass of the carrier. At the time of immobilization, the lipase is brought into a solution state, but it is preferable to use it after adjusting the pH to 5 to 7 using a buffer. The temperature at the time of immobilization is preferably 0 to 60C, more preferably 5 to 40C.

In order to increase the activity of the immobilized lipase, a treatment for adsorbing a fat-soluble fatty acid or a derivative thereof to a carrier may be performed before immobilizing the lipase. Examples of the method of performing the treatment include a method in which a fat-soluble fatty acid or a derivative thereof is once dispersed and dissolved in an organic solvent such as chloroform, hexane, and ethanol, and then added to a carrier dispersed in water.
As the fat-soluble fatty acid to be used, a saturated or unsaturated, linear or branched, C8 to C18 fatty acid which may be substituted with a hydroxyl group is exemplified. Specific examples include capric acid, lauric acid, myristic acid, oleic acid, linoleic acid, α-linolenic acid, and ricinoleic acid. Examples of the derivatives include esters of these fatty acids and monohydric or polyhydric alcohols, phospholipids, and derivatives obtained by adding ethylene oxide to these esters. Specific examples include the methyl esters, ethyl esters, monoglycerides, diglycerides, the ethylene oxide adducts thereof, polyglycerin esters, sorbitan esters, and sucrose esters of the above fatty acids. Two or more of these fat-soluble fatty acids or derivatives thereof may be used in combination.

(Partially hydrolyzed oil)
In the present invention, the partially hydrolyzed oil is obtained by partially hydrolyzing an oil or fat using a 1,3-position selective lipase, and contains 65% by mass or more of 1,2-diacylglycerol in diacylglycerol.

The fats and oils to be partially hydrolyzed may be vegetable fats or animal fats, for example, soybean oil, rapeseed oil, safflower oil, rice oil, corn oil, sunflower oil, cottonseed oil, olive oil, sesame oil, peanut Oil, adlay oil, wheat germ oil, perilla oil, linseed oil, sesame oil, chia seed oil, sacha inch oil, walnut oil, kiwi seed oil, salvia seed oil, grape seed oil, macadamia nut oil, hazelnut oil, pumpkin seed oil, camellia oil Vegetable oils such as tea oil, borage oil, palm oil, palm olein, palm stearin, palm oil, palm kernel oil, cocoa butter, monkey fat, shea butter, algal oil; fish oil, lard, beef tallow, butter fat And the like; and oils and fats such as transesterified oil, hydrogenated oil and fractionated oil thereof. These fats and oils may be used alone or in combination of two or more.
Above all, from the viewpoint of usability, it is preferable to use liquid fats and oils having excellent low-temperature resistance, and it is more preferable to use edible fats and oils having a low content of ω3 polyunsaturated fatty acids as a source of the fats and oils. It is preferable to use one or more kinds selected from vegetable seed oils such as rapeseed oil, safflower oil, corn oil, sunflower oil, cottonseed oil, olive oil, sesame oil, peanut oil, barley oil, wheat germ oil, and soybean oil Or rapeseed oil is preferred. In addition, the liquid fats and oils means the fats and oils which are liquid at 20 degreeC, when a cooling test by the standard fats and oils analysis test method 2.3.8-27 is implemented.
Hereinafter, the fat or oil to be subjected to partial hydrolysis is also referred to as a first fat or oil.

  The fatty acid constituting the first fat or oil is not particularly limited, and may be either a saturated fatty acid or an unsaturated fatty acid. However, it is preferable that 60 to 100% by mass of the fatty acid constituting the fat or oil is an unsaturated fatty acid. More preferably, 70 to 99% by mass, more preferably 75 to 97% by mass, and still more preferably 80 to 95% by mass are unsaturated fatty acids in terms of appearance and industrial productivity of fats and oils. The unsaturated fatty acid preferably has 14 to 24, more preferably 16 to 22, carbon atoms from the viewpoint of physiological effects. In addition, the fatty acid amount in this specification is a free fatty acid equivalent amount.

  Further, the content of the saturated fatty acid in the fatty acids constituting the first fat or oil is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less from the viewpoint of suppressing crystal precipitation at a low temperature. And more preferably 10% by mass or less. Moreover, it is preferable that it is 0.5 mass% or more from a point of industrial productivity of fats and oils. As the saturated fatty acids, those having 14 to 24 carbon atoms, more preferably 16 to 22 carbon atoms are preferable.

  It is preferable that after the first fat or oil is squeezed from a plant or animal as a raw material, solid components other than the oil component are removed by filtration or centrifugation. Next, it is preferable to add and mix water and, in some cases, an acid, and then remove the gum by separating the gum component by centrifugation or the like. Moreover, it is preferable to deacidify the fats and oils by adding and mixing an alkali, followed by washing with water and dehydration. Further, it is preferable that the fats and oils are decolorized by contacting with an adsorbent such as activated clay and then separating the adsorbent by filtration or the like. Further, deodorization is a process of removing unpleasant odors and taste substances to obtain a refined oil having good flavor, hue, and storage stability, and removing odorous components while blowing steam under high temperature and reduced pressure conditions. It is preferable to carry out steam deodorization. These processes are preferably performed in the above order, but the order may be changed. In addition to the above, the oil and fat may be subjected to wintering for separating solids at a low temperature in order to remove wax.

  The hydrolysis activity of the 1,3-position selective lipase acting on the first fat or oil is preferably 20 U / g or more, more preferably 100 to 10,000 U / g, and further preferably 500 to 5000 U / g. Is preferred. Here, 1 U of the enzyme is an enzyme that produces 1 μmol of free fatty acid per minute when the mixture is hydrolyzed at 40 ° C. for 30 minutes while stirring and mixing a mixture of oil and water = 100: 25 (mass ratio). Is shown. The 1,3-position selective lipase may be used in a packed column or in a stirred tank, but it may be used in a packed column in order to suppress the crushing of the immobilized enzyme. preferable.

  The amount of immobilized enzyme can be appropriately determined in consideration of the activity of the enzyme, but is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, based on 100 parts by mass of the first fat or oil. Further, the amount of water is preferably 0.5 to 200 parts by mass, more preferably 1 to 100 parts by mass, and further preferably 2 to 80 parts by mass with respect to 100 parts by mass of the first fat and oil. The water may be any of distilled water, ion-exchanged water, degassed water, tap water, well water, and the like. If necessary, a buffer having a pH of 3 to 9 may be used to maintain the stability of the enzyme.

The reaction temperature is preferably 0 to 70 ° C., which is a temperature at which free fatty acids generated by decomposition do not become crystals, and more preferably 20 to 50 ° C., in which the activity of the enzyme is more effectively extracted and the transfer reaction of diacylglycerol is suppressed. .
The pressure in the reaction system is not particularly limited, and the reaction can be performed under normal pressure or reduced pressure. In the case of normal pressure, it is preferable from the viewpoint of reactivity to use a nitrogen stream so as to avoid contact with air as much as possible.

  The partial hydrolysis of the first fat or oil can be performed in a batch system, a continuous system, or a semi-continuous system. The supply of fats and oils and water into the apparatus may be either a co-current type or a counter-current type. It is preferable to use oils and fats and water which have been degassed or deoxygenated beforehand as necessary from the viewpoint of suppressing oxidation of the oils and fats.

The partial hydrolysis reaction of the first fat or oil is preferably performed in a free fatty acid concentration range of 3 to 40%. By performing in such a range, as described later, a large amount of diacylglycerol is generated, and the concentration of 1,2-diacylglycerol in the diacylglycerol is increased. The partial hydrolysis reaction is controlled by the free fatty acid concentration represented by the following formula (1), and may be terminated when a predetermined decomposition rate is reached.
Free fatty acid concentration (%) = acid value of partially hydrolyzed oil (AV) / average molecular weight of fatty acid of first fat / oil / 56.10 / 10 (1)
The free fatty acid concentration in the partial hydrolysis reaction is preferably 5 to 30%, more preferably 10 to 25%, from the viewpoint of suppressing the transfer reaction of diacylglycerol.

The cracked oil obtained by the partial hydrolysis reaction contains unreacted fats and oils, that is, triacylglycerol, diacylglycerol and monoacylglycerol, in addition to fatty acids. In particular, diacylglycerol contains a large amount of 1,2-diacylglycerol.
In the present invention, after the partial hydrolysis reaction, the cracked oil can be used for the esterification reaction described below without performing the distillation operation, but it is preferable to reduce the fatty acid concentration by performing the distillation operation. The distillation conditions are not particularly limited.
After the distillation operation, the content of free fatty acids in the partially hydrolyzed oil to be subjected to the esterification reaction described below is 5% by mass or less, and further 3% by mass, in that unreacted ω3-based highly unsaturated fatty acids are recovered at a high concentration. %, More preferably 1.5% by mass or less.

The content of diacylglycerol in the partially hydrolyzed oil to be subjected to the esterification reaction is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, from the viewpoint of suppressing the transfer reaction of diacylglycerol.
Further, the content of 1,2-diacylglycerol in diacylglycerol is at least 65% by mass, but from the same point, at least 68% by mass is preferable.

(Fatty acids)
The fatty acids used in the present invention contain ω3 highly unsaturated fatty acids, and have an acid value of 125 to 180 mgKOH / g.
Fatty acids may contain acyl glycerol (triacyl glycerol, diacyl glycerol, monoacyl glycerol) and the like in addition to fatty acids.
The acid value (AV) of the fatty acids is from 125 to 180 mgKOH / g, but is preferably at least 135 mgKOH / g, more preferably at least 145 mgKOH / g, from the viewpoint of suppressing the production of diacylglycerol in the esterification reaction.

Fatty acids preferably contain at least 40% by mass of ω3 highly unsaturated fatty acids, more preferably 45 to 60% by mass, so that the ω3 highly unsaturated fatty acids easily act in the esterification reaction. .
In addition, the content of docosahexaenoic acid in the fatty acids is preferably 38% by mass or more, and more preferably 43 to 58% by mass, from the same point.

In the present invention, it is preferable to obtain fatty acids by hydrolyzing fats and oils.
Here, the fats and oils to be hydrolyzed (hereinafter, also referred to as second fats and oils) may be any of vegetable fats and oils and animal fats and oils, but fats and oils containing ω3 highly unsaturated fatty acids as constituent fatty acids are preferred. . Examples of such fats and oils include microbial oils such as fish oil and algal oil, and these may be used alone or in combination of two or more. Fish oils are marine animal fats and oils, for example, can be collected from raw materials such as sardines, herring, saury, mackerel, bonito, tuna, whales, squid, and cod liver. Algae oil can be collected from algae belonging to the class of green algae, diatoms and the like. Further, a so-called ω3-based highly unsaturated fatty acid-enriched oil in which the ratio of ω3-based highly unsaturated fatty acids in the fatty acids constituting the fats and oils is increased may be used. As a method for increasing the ratio of the ω3 polyunsaturated fatty acid in the constituent fatty acids, a conventionally known method, for example, a method of preferentially releasing / removing a fatty acid other than the ω3 polyunsaturated fatty acid using lipase or a solvent Any of the methods can be used.

In the second fat or oil, the content of the ω3 polyunsaturated fatty acid with respect to all fatty acids constituting the fat or oil is 10% by mass or more from the viewpoint that the ω3 polyunsaturated fatty acid easily acts in the esterification reaction. It is preferably 15 to 43% by mass, more preferably 20 to 38% by mass.
In addition, the content of docosahexaenoic acid with respect to all fatty acids constituting the second fat or oil is preferably 10% by mass or more from the same point, more preferably 13 to 38% by mass, further 18 to 41% by mass, further 16% by mass. It is preferably about 36% by mass.

Examples of the method for hydrolyzing the second fat / oil include a high-temperature and high-pressure decomposition method and an enzymatic decomposition method.
The high-temperature and high-pressure decomposition method is a method in which fatty acid and glycerin are obtained by adding water to fats and oils and reacting under high-temperature and high-pressure conditions. In addition, the enzymatic decomposition method is a method in which fatty acid and glycerin are obtained by adding water to fats and oils, and using the fat and oil hydrolase as a catalyst and reacting at low temperature conditions. Above all, an enzymatic decomposition method using an oil hydrolase is preferred from the viewpoint of suppressing the trans-formation of ω3-based highly unsaturated fatty acids.
Lipase is preferably used as the oil / fat hydrolyzing enzyme, and is not particularly limited, and the above-mentioned lipase derived from animals, plants and microorganisms can be used. Above all, it is preferable to use a non-selective lipase from the viewpoint of hydrolysis efficiency, and it is more preferable to use a non-selective lipase produced by Candida cylindracea.

  After the hydrolysis reaction of the second fat or oil, free fatty acids are removed. The method for removing free fatty acids is not particularly limited, such as alkali decomposition and distillation. However, from the viewpoint of industrial productivity, the distillation treatment is preferably performed using a thin-film evaporator. Examples of the thin-film evaporator include a centrifugal thin-film evaporator, a falling-film evaporator, and a wiped-film evaporator, depending on the method for forming a thin film.

After the hydrolysis reaction of the second fat and oil, it is preferable that the distilled oil from which free fatty acids have been removed by distillation is further subjected to a hydrolysis reaction. Lipase is preferably used as the oil / fat hydrolyzing enzyme, and is not particularly limited, and the above-mentioned lipase derived from animals, plants and microorganisms can be used. Above all, from the viewpoint of hydrolysis efficiency, a non-selective lipase produced by Candida cylindracea and a lipase preferentially hydrolyzing the 1,3-position produced by Alcaligenes sp. It is preferable to use
From the viewpoint of efficiency, a partial glyceride lipase produced by Penicillium camembertii may be used in combination. Partial glyceride lipase is a lipase that hydrolyzes monoacylglycerol and diacylglycerol, but hardly hydrolyzes triacylglycerol.

The hydrolysis reaction can be performed according to a conventional method.
After the hydrolysis, a distillation operation may be performed under the conditions satisfying the above-mentioned acid value (AV). However, preferably, the fatty acid is used for the esterification reaction described below without performing the distillation operation. It is preferable from the viewpoint of cost if undistilled fatty acids can be used as the esterification reaction raw material.

(Esterification reaction)
In the present invention, a method of esterifying a partially hydrolyzed oil and a fatty acid using a 1,3-position selective lipase can be performed according to a conventional method.
The amount of the immobilized enzyme used in the ester reaction can be appropriately determined in consideration of the activity of the enzyme. However, the amount of the immobilized enzyme is 1 to 30% by mass, and more -20% by mass is preferred.

  The mass ratio of the partially hydrolyzed oil to the fatty acids at the time of performing the esterification reaction [partially hydrolyzed oil / fatty acids] is 0.2 to 5, more preferably 0.5 to 4, because the production efficiency is increased. 1-3 are preferable.

The reaction temperature of the esterification reaction is preferably 0 to 100 ° C., more preferably 20 to 80 ° C., and further preferably 30 to 60 ° C., from the viewpoint of improving the reaction rate and suppressing the deactivation of the enzyme.
In addition, the reaction time is preferably 1 to 120 hours, more preferably 2 to 60 hours, and further preferably 3 to 30 hours from the viewpoint of suppressing the transfer reaction of diacylglycerol and industrial productivity.

  The esterification reaction is preferably carried out while removing the reaction product water from the reaction system from the viewpoint of efficiently obtaining triacylglycerol. For example, it is preferable to remove the system out of the system by a method such as pressure reduction; use of an absorbent such as zeolite or molecular sieve; ventilation of a dry inert gas into a reaction tank.

  Examples of the means for contacting the 1,3-position selective lipase with the raw materials (partially hydrolyzed oil and fatty acids) include a method of immersing, stirring, and passing a liquid through a column filled with immobilized lipase by a pump or the like. In the case of stirring, it is preferably from 10 to 1000 r / min, more preferably from 50 to 700 r / min, further preferably from 100 to 600 r / min, from the viewpoint of production efficiency and suppression of lipase crushing.

  The pressure in the reaction system is preferably reduced pressure, preferably 1 to 10000 Pa, more preferably 10 to 5000 Pa, and further preferably 100 to 3000 Pa.

The reaction product after the esterification reaction contains fats and oils, that is, triacylglycerol, diacylglycerol and monoacylglycerol, and fatty acids as unreacted substances. By-products can be suppressed. Further, the ω3-based polyunsaturated fatty acid in the reaction product binds to the 1,3-position more selectively than the 2-position of glycerol.
In the present invention, after the esterification reaction, a distillation operation is preferably performed to remove monoacylglycerol and fatty acids from the reaction oil.

The distillation treatment is preferably performed using a thin-film evaporator. Examples of the thin-film evaporator include a centrifugal thin-film evaporator, a falling-film evaporator, and a wiped-film evaporator, depending on the method for forming a thin film.
The pressure is preferably reduced from the viewpoint of removing volatile odorous components, reducing equipment costs and operating costs, increasing distillation capacity, and optimally selecting a distillation temperature. It is preferably 200 Pa, more preferably 2 to 100 Pa.
The temperature is preferably from 180 to 280C, more preferably from 190 to 260C, and further preferably from 195 to 250C, from the viewpoint of removing volatile odorous components and improving the flavor.
The residence time is preferably from 5 to 120 seconds, more preferably from 10 to 90 seconds, and further preferably from 15 to 60 seconds, from the viewpoint of removing volatile odorous components and improving the flavor.

As a result of the treatment of the present invention, a structural fat or oil containing a high proportion of ω3-based polyunsaturated fatty acids bonded to the 1,3-positions of glycerol and containing triacylglycerol in a high concentration can be obtained.
On the other hand, the distillation fraction after the distillation treatment contains a large amount of ω3-based highly unsaturated fatty acids. Therefore, according to the method of the present invention, ω3 polyunsaturated fatty acids can be effectively used without loss. The content of docosahexaenoic acid in the distillation fraction is preferably 41% by mass or more, more preferably 45% by mass or more, and further preferably 48% by mass or more in consideration of reuse as raw material fatty acids.

In the structural fats and oils of the present invention, 75% by mass or more of the ω3 polyunsaturated fatty acids in the constituent fatty acids are bonded to the 1,3-positions of glycerol. Is preferably 81% by mass or more, more preferably 83% by mass or more from the viewpoint of favorably exerting physiological functions.
The ratio of the ω3 polyunsaturated fatty acid bound to the 1,3-position is the ratio of the ω3-polyunsaturated fatty acid bound to the glycerol 1,3-position to the total amount of the ω3-polyunsaturated fatty acid in the constituent fatty acids. Is expressed as a percentage.
The fatty acid compositions at the 1- and 3-positions of fats and oils can be determined by analyzing the composition of all the fatty acids constituting the fats and oils and the composition of the fatty acid bonded to the 2-position of the fats and oils. Details are described in Examples below.

  The content of the ω3 polyunsaturated fatty acid in the fatty acids constituting the structural fats and oils is preferably 5 to 15% by mass, more preferably 6 to 14% by mass, from the viewpoint of favorably exerting physiological functions.

In the structural fats and oils of the present invention, the ratio of docosahexaenoic acid bonded to the 1,3-positions of glycerol to the total mass of docosahexaenoic acid in the constituent fatty acids (1,3-position DHA content) is advantageous in expressing physiological functions. Therefore, the content is preferably 75% by mass or more, and more preferably 81 to 89.5% by mass.
Further, the content of docosahexaenoic acid in the fatty acids constituting the structural fats and oils is preferably 4.2% by mass or more, more preferably 4.2 to 13% by mass, further 5 to 13% by mass, further 6% from the viewpoint of fats and oils properties. -12% by mass is preferred. Structural fats containing docosahexaenoic acid in the constituent fatty acids at such a ratio and having a high proportion of docosahexaenoic acid bonded to the 1,3-positions of glycerol as high as 75% by mass or more show that most of docosahexaenoic acid is the first or third glycerol It is considered to be bound to any one of the positions, and is preferable from the viewpoint of efficient use of docosahexaenoic acid in vivo.

In the structural fats and oils of the present invention, the content of triacylglycerol is 91% by mass or more, preferably 91 to 96% by mass, more preferably 92 to 96% by mass.
Further, the total content of diacylglycerol and monoacylglycerol in the structural fat is 9% by mass or less, preferably 4 to 8% by mass.

  The structural fats and oils obtained by the method of the present invention can be used in the same manner as general edible fats and oils by subjecting them to a purification step as required.

[Analysis method]
(I) Measurement of Constituent Fatty Acid Composition According to the “Methyl Esterification Method (Boron Trifluoride Methanol Method) (2.4.1.2-1996)” in “Standard Oil and Fat Analysis Test Method 2003 Edition” edited by Japan Oil Chemists' Society. It was measured. Fatty acid methyl esters were prepared from samples using trihenicosanoin (manufactured by Wako Pure Chemical Industries) as an internal standard, and the obtained samples were subjected to gas chromatography (GLC) to analyze constituent fatty acids. The fatty acid average molecular weight was calculated from the constituent fatty acids.

(Ii) Measurement of glyceride composition “Glyceride composition” was measured by adding 10 mg of a sample and 0.5 mL of a trimethylsilylating agent (“Silylating agent TH”, manufactured by Kanto Chemical) to a glass sample bottle, sealing the mixture at 70 ° C. Heat for 15 minutes. To this, 1.0 mL of distilled water and 2.0 mL of hexane were added, and after mixing, the hexane layer was subjected to gas chromatography (GLC) to analyze the glyceride composition.

(Iii) Measurement of acid value (AV) The acid value (AV) was measured according to “Acid value (2.3.1-1996)” in “Standard fat and oil analysis test method, 2003 edition” edited by Japan Oil Chemists' Society.

(Iv) Measurement of fatty acid composition at the 2-position and fatty acid composition at the 1- and 3-positions Novozyme 435 (Novozyme 435 (Novozyme) which shows high 1,3-position selectivity in the presence of high concentration of ethanol and has low fatty acid selectivity with existing lipase agents Manufactured by Zymes Japan). The fatty acid composition of 2-monoglyceride was determined by decomposing the 1,3-linked fatty acid of glyceride, and the 1,3-position fatty acid composition was calculated.
150 mg of sample and 1.5 g of ethanol were mixed, 66 mg of Novozyme 435 (manufactured by Novozymes Japan) was added, and reacted at 30 ° C. for 3 hours. Thereafter, the lipase was separated by filtration, and ethanol was distilled off under reduced pressure to obtain a reaction solution.
Subsequently, 2-monoglyceride was fractionated using a solid phase column (Sep-Pak Silica WAT051900, manufactured by Nippon Waters). The solid phase column was conditioned with 10 mL of a mixed solvent of 80% hexane and 20% diethyl ether. 100 mg of the reaction solution was dissolved in 1 mL of a mixed solvent of 80% hexane and 20% diethyl ether and passed through a solid phase column. Next, 30 mL of a mixed solvent of 80% hexane and 20% diethyl ether was passed through to separate free fatty acids and diglycerides. Thereafter, 10 mL of methanol was passed. The methanol was distilled off under reduced pressure to collect a 2-monoglyceride fraction. Then, using trihenicosanoin (manufactured by Wako Pure Chemical Industries) as an internal standard, the same operation as the measurement of the constituent fatty acid composition was performed to analyze the constituent fatty acids of the 2-monoglyceride fraction.
Using the results, the composition (% by mass) of the constituent fatty acids at the 1,3-position was calculated by the following equation (1).
Composition of fatty acids at the 1,3-positions (mass%) = {Composition of fatty acids of glyceride (mass%) × Composition of fatty acids of 3-glyceride at 2-position (mass%)} / 2 (1)

Further, the ratio of the fatty acid bonded at the 1,3-position was calculated as the 1,3-position content (% by mass) from the following equation (2).
1,3-position content (% by mass) = {1,3-position constituent fatty acid composition (% by mass) × 2} / {glyceride constituent fatty acid composition (% by mass) × 3} × 100 (2)

<Method for producing immobilized lipase AY>
Duolite A-568 (manufactured by Sasaki Chemical) was used as a carrier for immobilizing lipase. 1000 g of the carrier was stirred in 10 L of a N / 10 NaOH solution for 1 hour and filtered. Thereafter, the mixture was stirred in 10 L of ion-exchanged water for 1 hour, filtered, equilibrated with 10 L of 500 mM phosphate buffer (pH 7) for 2 hours, and filtered. Thereafter, an operation of pH equilibration with 10 L of a 50 mM phosphate buffer (pH 7) for 2 hours and filtration was performed twice. Thereafter, ethanol replacement with 5 L of ethanol was performed for 30 minutes, followed by filtration. Thereafter, 5 L of ethanol containing 1000 g of soybean fatty acid excluding the high melting point component precipitated at −3 ° C. was added, and the fatty acid was adsorbed on the carrier for 30 minutes, followed by filtration. Thereafter, the carrier was washed four times with 5 L of 50 mM phosphate buffer (pH 7) for 30 minutes each, ethanol was removed, and the carrier was recovered by filtration. Thereafter, 1000 g of a commercially available lipase (lipase AY “Amano” 30SD-K derived from the genus Candida cylindracea, manufactured by Amano Enzyme) was contacted with an enzyme solution dissolved in 9000 g of 50 mM phosphate buffer (pH 7) for 5 hours to immobilize the lipase. Was performed. Thereafter, the carrier was filtered, and the lipase-immobilized carrier was washed with 10 L of a 50 mM phosphate buffer (pH 7) to remove unimmobilized enzymes and proteins. Thereafter, 4000 g of tuna crude oil was added and stirred for 12 hours. All of the above operations were performed at 20 ° C. Thereafter, the mixture was filtered, the oils and fats were washed with hexane, and the solvent was removed to obtain immobilized lipase AY.

<Method for producing immobilized lipase QLM>
Immobilized lipase QLM was obtained by the same production method as immobilized lipase AY, except that the type of lipase was changed to lipase derived from the genus Alcaligenes (Lipase QLM, manufactured by Meito Sangyo).

<Method for producing immobilized lipase G>
In the same production method as the immobilized lipase AY, the type of lipase was changed to a partial glyceride lipase derived from the genus Penicillium (Lipase G "Amano" 50, manufactured by Amano Enzyme), and a phosphate buffer (pH 7) was added to an acetate buffer ( pH 5) was changed to obtain immobilized lipase G.

<Method for producing partially hydrolyzed oil derived from rapeseed oil>
1. Partial hydrolysis Rapeseed oil was used as the first fat. 2000 g of rapeseed oil and 100 g of distilled water are charged into a four-necked flask, and 100 g of 1,3-position selective lipase (Lipozyme RM IM, Novozyme Japan, hereinafter the same) is allowed to act while stirring at a temperature of 30 ° C. and 400 r / min. And partially hydrolyzed for 2 hours to obtain a 1,3-decomposed oil. The free fatty acid concentration was 17-20%.
Thereafter, the Lipozyme RM IM was separated by filtration to obtain a 1,3-decomposed oil derived from rapeseed oil.

2. Distillation The 1,3-decomposed oil obtained in 1 above was thin-filmed using a wiped film evaporator (type 2-03: Shinko Environmental Solutions) at a temperature setting of 180 ° C., a vacuum of <2 Pa, and a flow rate of 150 mL / h. Distillation was performed to obtain a partially hydrolyzed oil. Table 1 shows the analysis values of the partially hydrolyzed oil.

<Method for producing fatty acids derived from tuna oil>
1. Enzymatic hydrolysis reaction Tuna crude oil containing 7.9% by mass of EPA and 28.5% by mass of DHA is subjected to a batch agitation reaction in a four-necked flask to carry out a hydrolysis reaction with lipase which is unlikely to hydrolyze DHA, and to obtain DHA in glyceride. Increased concentration.
Next, 2000 g of tuna crude oil and 2000 g of distilled water were charged, and 200 g of immobilized lipase AY was added thereto while stirring at a temperature of 40 ° C. and 400 r / min, and a hydrolysis reaction was performed for 2 hours. After the immobilized enzyme was filtered off, the sweet water was separated by centrifugation (Rotor R9A, manufactured by Hitachi Koki, 8000 r / min × 10 min). Thereafter, the oil phase was dehydrated under reduced pressure to obtain a tuna crude oil decomposed oil. This operation was repeated twice to obtain a tuna crude oil decomposed oil.

2. Distillation The cracked oil obtained in the above 1 was subjected to thin-film distillation using a wiped film evaporator (type 2-03: Shinko Environmental Solutions) under the conditions of a temperature setting of 230 ° C., a vacuum of <2 Pa, and a flow rate of 150 mL / h, Free fatty acids were distilled off.

3. Enzymatic hydrolysis reaction 1500 g of the residue distilled in the above 2 and 1500 g of distilled water are charged into a four-necked flask, and 150 g of immobilized lipase QLM and 150 g of immobilized lipase G are added while stirring at a temperature of 40 ° C. and 400 r / min. A high concentration DHA fatty acid was obtained by performing a hydrolysis reaction by a batch stirring reaction. After sampling over time, the immobilized lipase was separated by filtration, and the oil phase was dehydrated under reduced pressure to obtain seven kinds of fatty acids having different acid values (AV). Table 1 shows the analysis values of fatty acids.

<Method for producing distilled fatty acids>
The fatty acids of Test Example 7 below were further treated using a wiped film evaporator (type 2-03: Shinko Environmental Solutions) under the conditions of a temperature setting of 230 ° C., a vacuum of <2 Pa, and a flow rate of 150 ml / h. Table 1 shows the analysis values of the obtained fatty acids. From the glyceride analysis results, there was no peak of MAG, DAG, and TAG, and the fatty acid concentration was almost 100% by mass.

[Test Examples 1 to 7]
1. Esterification reaction A partially hydrolyzed oil derived from rapeseed oil and fatty acids derived from tuna oil are charged into a four-necked flask at the ratio shown in Table 1, and Lipozyme RM IM is added at 10% to the total of the partially hydrolyzed oil and fatty acids. Then, while stirring at a temperature of 50 ° C. and 400 r / min, the esterification reaction was performed for 24 hours under the condition of a degree of vacuum of 400 Pa. Thereafter, the Lipozyme RM IM was separated by filtration to obtain a reaction oil. Table 1 shows the analysis values of the esterification reaction oil.

2. Distillation of esterification reaction oil The esterification reaction oil obtained in the above 1 was heated at a temperature of 230 ° C, a vacuum of <2 Pa, and a flow rate of 120 mL / h using a wiped film evaporator (type 2-03: manufactured by Shinko Environmental Solutions). Under the conditions, a thin film distillation treatment was performed.

[Test Example 8]
An esterification reaction oil was obtained in the same manner as in Test Example 1 except that the fatty acids derived from tuna oil were changed to distilled fatty acids, and then subjected to a thin-film distillation treatment.

  Table 1 shows the analytical values of the distillation residue and the distillation fraction obtained in Test Examples 1 to 8. In Table 1, the ratio of EPA bound to the 1,3-position of glycerol is the content of EPA at 1,3-position (% by mass), the ratio of DHA is the content of DHA at 1,3-position (% by mass), and the total of EPA and DHA. Is shown by the 1,3-position EPA + DHA content (% by mass).

As is evident from Table 1, the TAG concentration is high and 1,1 by performing the esterification reaction using a predetermined partially hydrolyzed oil and fatty acids having an undistilled acid value in the range of 125 to 180 mgKOH / g as raw materials. It is found that the content of the 3-position EPA + DHA is as high as 80% by mass or more, and the content of the 1,3-position DHA is as high as 75% by mass or more. Was. Since the DHA concentration in the glyceride was 4.4 to 12.7% by mass, it was considered that most of the DHA was bound to either the first or third position of glycerol.
Further, the DHA concentration of the distillation fraction was 41% by mass or more, which was reusable as an esterification raw material.
On the other hand, when the acid value of the fatty acids is low, the DHA concentration in the glyceride increases, but the TAG concentration is low, and the 1,3-position EPA + DHA content and the 1,3-position DHA content also decrease. . In addition, it was found that when distilled fatty acids having a high acid value were used, DHA was selectively bonded to the 1,3-position, but DHA in glyceride was low.

Claims (8)

  A method for producing a structural fat or oil in which 75% by mass or more of the ω3 polyunsaturated fatty acid in the constituent fatty acids is bonded to the 1,3-position of glycerol, wherein the fat or oil is partially hydrolyzed using a 1,3-position-selective lipase. And a partially hydrolyzed oil containing 1,2-diacylglycerol in an amount of 65% by mass or more in diacylglycerol, and a fatty acid containing an ω3-highly unsaturated fatty acid and having an acid value of 125 to 180 mgKOH / g. , An esterification reaction using a 1,3-position selective lipase.   The method for producing a structured fat or oil according to claim 1, wherein the fatty acid contains at least 40% by mass of the ω3-based highly unsaturated fatty acid.   The method according to claim 1 or 2, wherein the partially hydrolyzed oil contains 5 to 30% by mass of diacylglycerol.   The method for producing a structured fat or oil according to any one of claims 1 to 3, wherein the partially hydrolyzed oil is obtained by partially hydrolyzing rapeseed oil, and the fatty acids are obtained by hydrolyzing fish oil.   The production of the structured fat or oil according to any one of claims 1 to 4, wherein the mass ratio of the partially hydrolyzed oil to the fatty acid [partially hydrolyzed oil / fatty acids] is 0.2 to 5 when the esterification reaction is performed. Method.   The method for producing a structured fat or oil according to any one of claims 1 to 5, wherein the structured fat or oil contains 4.2 to 13% by mass of docosahexaenoic acid in a fatty acid constituting the fat or oil.   The method for producing a structured fat or oil according to any one of claims 1 to 6, wherein the structured fat or oil contains 91 to 96% by mass of triacylglycerol.   The method for producing a structured fat or oil according to any one of claims 1 to 7, wherein after the esterification reaction, the ω3-based polyunsaturated fatty acid is recovered as a fraction by a distillation operation and reused as part or all of the fatty acids.