Production method for transesterified oil / fat

Abstract

Provided is a method for producing a transesterified oil / fat rich in diacylglycerol with a small amount of by-products without changing a glyceride composition of a reaction oil.　The present invention provides a production method for a transesterified oil / fat, the method including subjecting an oil / fat and glycerin to a transesterification reaction, subsequently performing a process of reducing glycerin dissolved in a reaction oil, and subsequently performing a process of bringing an adsorbent into contact with the glycerin-free oil.

Description

Method for producing interesterified oils and fats

[0001] The present invention relates to a method for producing interesterified fats and oils rich in diacylglycerol.

[0002] Diacylglycerol is used in various industrial fields, such as food and cosmetics. Diacylglycerol is generally produced by an esterification reaction between glycerin and a fatty acid or a glycerolysis reaction (transesterification reaction) between glycerin and a fat or oil. These production methods are broadly divided into chemical methods using chemical catalysts such as hydroxides or alkoxides of alkali metals or alkaline earth metals, and enzymatic methods using enzymes such as lipase. To make the diacylglycerol after the esterification reaction or transesterification reaction suitable for consumption, it is subjected to decolorization by adding activated clay or the like, or deodorization by contacting it with steam at high temperature and reduced pressure (see, for example, Patent Documents 1 to 3). Patent Document 3 discloses that oil or fat containing less glycidol fatty acid esters as by-products can be obtained by contacting a fat or oil resulting from an esterification reaction of fatty acids and glycerin with steam, followed by contacting it with an adsorbent such as activated clay.

[0003] (Patent Document 1) JP-T-2005-504862 A (Patent Document 2) JP-A-2020-172576 (Patent Document 3) JP-A-2011-195621

[0004] The present invention provides a method for producing interesterified fats and oils, which comprises subjecting fats and oils to an interesterification reaction with glycerin, followed by a treatment to reduce the amount of glycerin dissolved in the reaction oil, and then a treatment to bring the deglycerinated oil into contact with an adsorbent. Detailed Description of the Invention

[0005] However, it has been found that even when a treatment of transesterification reaction oil (hereinafter also simply referred to as "reaction oil") is performed by contacting an adsorbent such as activated clay, the amount of by-products may not be sufficiently reduced, and therefore reduction of by-products is desired. On the other hand, the reaction oil contains not only diacylglycerol but also triacylglycerol and monoacylglycerol, and in order to effectively utilize the physiological effects of diacylglycerol and monoacylglycerol, it is desirable to maintain the glyceride composition of the reaction oil. Therefore, the present invention relates to a method for producing transesterification oils and fats that are rich in diacylglycerol and produce few by-products without changing the glyceride composition of the reaction oil.

[0006] The present inventors have discovered that the inability to sufficiently reduce by-products lies in glycerin dissolved in the reaction oil, and that by carrying out a treatment to reduce the glycerin dissolved in the reaction oil after the transesterification reaction (hereinafter, the oil or fat after the treatment to reduce glycerin is also referred to as "deglycerolized oil") and then carrying out a treatment to bring the deglycerolized oil into contact with an adsorbent, it is possible to sufficiently reduce by-products while maintaining the glyceride composition of the reaction oil, and to obtain a transesterified oil or fat rich in diacylglycerol with few by-products.

[0007] According to the present invention, interesterified oils and fats can be obtained that are rich in diacylglycerol and contain few by-products.

[0008] The method for producing interesterified fats and oils of the present invention involves transesterifying fats and oils with glycerin, followed by a treatment to reduce the amount of glycerin dissolved in the reaction oil, and then contacting the deglycerinated oil with an adsorbent. In this specification, "fat and oil" and "oil" are synonymous. Furthermore, the substances constituting fats and oils (oils) include not only triacylglycerols but also monoacylglycerols and diacylglycerols. In other words, fats and oils (oils) contain one or more of monoacylglycerols, diacylglycerols, and triacylglycerols.

[0009] In the present invention, the fats and oils to be reacted with glycerin are generally those mainly composed of triacylglycerol, and examples thereof include soybean oil, rapeseed oil, safflower oil, rice oil, corn oil, sunflower oil, cottonseed oil, olive oil, sesame oil, peanut oil, Job's tears oil, wheat germ oil, perilla oil, linseed oil, perilla oil, chia seed oil, sacha inchi oil, walnut oil, kiwi seed oil, salvia seed oil, grape seed oil, macadamia nut oil, and hazelnut oil. Examples of suitable oils include vegetable oils such as tallow oil, pumpkin seed oil, camellia oil, tea seed oil, borage oil, palm oil, palm olein, palm stearin, coconut oil, palm kernel oil, cocoa butter, monkey fat, shea butter, and algae oil; animal oils such as fish oil, seal oil, whale oil, lard, beef tallow, and butter fat; microbial oils such as oils derived from polyunsaturated fatty acid-producing microorganisms such as Zygomycetes; and interesterified oils, hydrogenated oils, and fractionated oils thereof. These oils and fats can be used alone or in combination of two or more. Among these, liquid oils and fats are preferred in terms of the emulsification properties and ease of handling of interesterified oils and fats. Liquid oils and fats refer to oils and fats that are liquid at 20°C when subjected to a cooling test according to Standard Fats, Oils, and Fat Analysis Test Method 2.3.8-27. Furthermore, in the present invention, it is preferable to use oils and fats containing fatty acids with a carbon chain length of 18 or more and with three or more double bonds, as these are expected to have various physiological functions. In particular, it is preferable to use one or more oils and fats selected from oils and fats rich in ω3 unsaturated fatty acids, such as perilla oil, linseed oil, perilla oil, chia seed oil, sacha inchi oil, algae oil, fish oil, seal oil, whale oil, and oils and fats derived from microorganisms that produce polyunsaturated fatty acids.

[0010] Fish oil can be extracted from raw materials such as sardines, herring, saury, mackerel, bonito, tuna, squid, and cod liver. Algal oil can be extracted from algae belonging to the Chlorophyceae, Bacillariophyceae, etc. It is preferable to appropriately perform known separation and purification methods such as liquid-liquid separation, filtration, and centrifugation to remove impurities before the reaction. Alternatively, so-called concentrated oils can be used, which are obtained by selectively hydrolyzing fish oils or the like using lipase to increase the proportion of unsaturated fatty acids such as eicosapentaenoic acid (C20:5, EPA) and docosahexaenoic acid (C22:6, DHA) in the fatty acids that make up the oil.

[0011] The triacylglycerol content in the oil or fat may be 100% by mass, but in order to facilitate the concentration of highly unsaturated fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, in the transesterified oil or fat, it is preferably 95% by mass or less, more preferably 92% by mass or less, and even more preferably 89% by mass or less. From the viewpoint of production efficiency, it is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. To reduce the triacylglycerol content in the oil or fat to be reacted with glycerin to less than 100% by mass, it is preferable to partially hydrolyze the oil or fat with lipase and then remove the resulting fatty acids by distillation. This operation allows selective removal of saturated fatty acids with 16 and 18 carbon atoms from the constituent fatty acids, thereby allowing the highly unsaturated fatty acids to be further concentrated in the oil or fat to be reacted with glycerin. Furthermore, the content of free fatty acids or salts thereof in the fats and oils is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 4% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of preventing catalyst deactivation, and is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, from the viewpoint of production efficiency.

[0012] The constituent fatty acids constituting the oils and fats are not particularly limited and may be either saturated or unsaturated fatty acids. From the viewpoint of handleability and industrial productivity of the oils and fats, the content of unsaturated fatty acids in the fatty acids constituting the oils and fats is preferably 60 to 100% by mass, more preferably 70 to 98% by mass, and even more preferably 80 to 96% by mass. From the viewpoint of physiological effects, the number of carbon atoms in the unsaturated fatty acids is preferably 14 to 24, more preferably 16 to 22, and even more preferably 18 to 22. The amount of fatty acid in this specification is the amount converted to free fatty acid.

[0013] In view of physiological activity, the fatty acids constituting the oils and fats preferably contain a large amount of fatty acids having a carbon chain length of 18 or more and three or more double bonds. Furthermore, according to the method of the present invention, it is possible to obtain an interesterified oil having a high proportion of fatty acids having a carbon chain length of 18 or more and three or more double bonds in the reacted oil, while preventing the proportion of such fatty acids in the reacted oil from becoming lower than the proportion of fatty acids having a carbon chain length of 18 or more and three or more double bonds in the reacted oil as the raw material. The total content of fatty acids having a carbon chain length of 18 or more and three or more double bonds in the fatty acids constituting the oils and fats is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and even more preferably 30% by mass or more, in view of physiological activity and ease of enjoying the effects of the present invention. Furthermore, in view of suppressing the by-production of trans fatty acids, it is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. The total content of fatty acids having a carbon chain length of 18 or more and three or more double bonds in the fatty acids constituting the oil or fat is preferably 15 to 99% by mass, more preferably 20 to 90% by mass, even more preferably 25 to 80% by mass, and even more preferably 30 to 80% by mass. Examples of fatty acids having a carbon chain length of 18 or more and three or more double bonds in the fatty acids constituting the oil or fat include α-linolenic acid (C18:3), γ-linolenic acid (C18:3), arachidonic acid (C20:4), eicosapentaenoic acid (C20:5, EPA), docosapentaenoic acid (C22:5), and docosahexaenoic acid (C22:6, DHA). Among these, ω3 unsaturated fatty acids having a double bond at the third position from the methyl end of the carbon chain are preferred in terms of physiological activity and ease of enjoying the effects of the present invention.

[0014] The glycerin used in the present invention preferably has a purity of 95% by mass or more in order to improve reactivity.

[0015] In the present invention, the ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] during the reaction of fats and oils with glycerin is preferably 2.0 or less, more preferably 1.7 or less, and even more preferably 1.4 or less, from the viewpoint of producing diacylglycerol, and is preferably 0.60 or more, more preferably 0.65 or more, and even more preferably 0.70 or more, from the viewpoint of reducing the amount of glycerin that does not dissolve in the oil phase. The ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] during the reaction of fats and oils with glycerin is preferably 0.60 to 2.0, more preferably 0.65 to 1.7, and even more preferably 0.70 to 1.7. The ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] is expressed by the following formula (1): FA / GLY=(moles of fatty acid+moles of monoacylglycerol+moles of diacylglycerol×2+moles of triacylglycerol×3) / (moles of glycerin+moles of monoacylglycerol+moles of diacylglycerol+moles of triacylglycerol) (1)

[0016] In the present invention, the transesterification reaction between fats and oils and glycerin may be carried out by a conventionally known method, either a chemical method or an enzymatic method, but a chemical method using a chemical catalyst is preferred in terms of accelerating the transesterification reaction. The chemical catalyst used in the present invention may be any that catalyzes the reaction. Examples include alkali metal hydroxides, alkaline earth metal hydroxides, and alkoxides having 1 to 3 carbon atoms. Examples of alkali metal hydroxides include sodium hydroxide and potassium hydroxide. Examples of alkaline earth metal hydroxides include calcium hydroxide, magnesium hydroxide, and barium hydroxide. Examples of alkoxides having 1 to 3 carbon atoms include sodium methoxide and sodium ethoxide. Of these, calcium hydroxide and sodium methoxide are preferred.

[0017] The amount of chemical catalyst added is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, based on the reaction raw materials (total of oils and fats and glycerin) from the viewpoint of improving reactivity; and is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1.5% by mass or less, based on the viewpoint of reducing the amount of neutralizing agent. When the chemical catalyst is calcium hydroxide or sodium methoxide, the amount added is preferably 0.04 to 1.5% by mass, based on the reaction raw materials, from the same viewpoint. In the present invention, the timing of adding the catalyst to the reaction raw materials is not particularly limited. After adding the catalyst to the reaction raw materials, the temperature is raised to the reaction temperature as necessary, and the transesterification reaction with the oils and fats and glycerin is carried out.

[0018] In the present invention, the reaction temperature is preferably 90 ° C. or higher, more preferably 95 ° C. or higher, and even more preferably 100 ° C. or higher from the viewpoint of improving the reaction rate. Also, from the viewpoint of reducing the content of by-products in the reaction oil, it is preferably 250 ° C. or lower, more preferably 235 ° C. or lower, and even more preferably 220 ° C. or lower. The reaction temperature is preferably 90 to 250 ° C., more preferably 95 to 235 ° C., and even more preferably 100 to 220 ° C. In addition, when using as a raw material an oil or fat to which a fatty acid having a carbon chain length of 18 or more and a double bond number of 3 or more is bonded, the upper limit of the temperature when carrying out the transesterification reaction is preferably 165 ° C. or lower, more preferably 160 ° C. or lower, and even more preferably 155 ° C. or lower, from the viewpoint of suppressing the production of trans acids. When using as a raw material an oil or fat to which a fatty acid having a carbon chain length of 18 or more and a double bond number of 3 or more is bonded, the reaction temperature is preferably 90 to 165 ° C., more preferably 95 to 160 ° C., and even more preferably 100 to 155 ° C.

[0019] The rate at which the reaction raw materials are heated to the reaction temperature is preferably 0.1°C / min or more, more preferably 0.15°C / min or more, and even more preferably 0.2°C / min or more, from the viewpoint of preventing catalyst deactivation and industrial productivity, and is preferably 20°C / min or less, more preferably 10°C / min or less, and even more preferably 3°C / min or less, from the viewpoint of reducing the heating load on the equipment. The rate at which the reaction raw materials are heated to the reaction temperature is preferably 0.1 to 20°C / min, more preferably 0.15 to 10°C / min, and even more preferably 0.2 to 3°C / min.

[0020] The reaction time is preferably 0.2 hours or more, more preferably 0.4 hours or more, and even more preferably 0.6 hours or more from the viewpoint of diacylglycerol production, and is preferably 15 hours or less, more preferably 12 hours or less, and even more preferably 9 hours or less from the viewpoint of industrial productivity. The reaction time is preferably 0.2 hours or more and 15 hours or less, more preferably 0.4 hours or more and 12 hours or less, and even more preferably 0.6 hours or more and 9 hours or less.

[0021] In order to improve reactivity and prevent a decrease in catalytic performance, the reaction between fats and oils and glycerin is preferably carried out after removing water contained in the reaction raw materials by reducing pressure, bubbling with nitrogen, etc. The water concentration of the reaction raw materials before addition of the catalyst is preferably 0.01 to 0.5% by mass, more preferably 0.03 to 0.4% by mass, and even more preferably 0.05 to 0.3% by mass, in terms of industrial productivity and preventing a decrease in catalytic performance.

[0022] The reaction may usually be carried out under reduced pressure or normal pressure. When the reaction is carried out under reduced pressure, the pressure is not particularly limited, but is preferably 13,000 Pa or less in order to reduce the water content in the reaction system. When the reaction is carried out under normal pressure, it is preferable to carry out the reaction under a nitrogen atmosphere in which nitrogen is circulated in order to suppress oxidation of the resulting interesterified oil or fat.

[0023] After the transesterification reaction is completed, the chemical catalyst used as a catalyst is mixed in the reaction oil. Therefore, after the transesterification reaction is completed, it is preferable to neutralize the chemical catalyst and remove it by filtration or the like. The neutralizing agent is not particularly limited, but acids such as sulfuric acid, hydrochloric acid, and phosphoric acid are preferred, and phosphoric acid is more preferred, because the neutralized product is insoluble in water and oils and can be easily removed by filtration.

[0024] In the present invention, the neutralization of the chemical catalyst is carried out by adding a neutralizing agent in an amount of preferably 0.7 molar or more, more preferably 0.8 molar or more, even more preferably 0.9 molar or more, even more preferably 1.2 molar or more, even more preferably 1.25 molar or more, and even more preferably 1.3 molar or more relative to the chemical catalyst in order to eliminate catalytic activity. The upper limit of the molar ratio is not particularly limited, but in order to suppress an increase in the acid value of the neutralized oil, it is preferably 3.0 molar or less, more preferably 2.6 molar or less, and even more preferably 2.2 molar or less. The amount of neutralizing agent relative to the chemical catalyst is preferably 0.7 to 3.0 molar, more preferably 0.8 to 2.6 molar, and even more preferably 0.9 to 2.2 molar. From the viewpoint of further reducing glycidol fatty acid esters, it is preferable that the molar ratio of the chemical catalyst to the neutralizing agent is close to equimolar, and the amount of the neutralizing agent relative to the chemical catalyst is preferably 0.7 to 1.3 times by mole, more preferably 0.8 to 1.2 times by mole, and even more preferably 0.9 to 1.1 times by mole.

[0025] The temperature in the neutralization step, i.e., the step from adding a neutralizing agent to the reaction oil containing the chemical catalyst until the stirring is completed (hereinafter the same), is preferably 20° C. or higher, more preferably 40° C. or higher, and even more preferably 60° C. or higher, from the viewpoint of sufficiently producing a neutralized product. Moreover, from the viewpoint of being able to suppress reverse reactions and oxidation, the temperature is preferably 250° C. or lower, more preferably 235° C. or lower, and even more preferably 220° C. or lower.

[0026] The time for the neutralization step is preferably from 1 to 240 minutes, more preferably from 3 to 180 minutes, and even more preferably from 10 to 120 minutes, from the viewpoint of sufficiently producing the neutralized product.

[0027] In the neutralization step, it is preferable to carry out the neutralization while stirring in order to sufficiently produce the neutralized product. The means for stirring is not particularly limited.

[0028] After the neutralization step, it is preferable to separate glycerin, which forms a different phase from the reaction oil. When the ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] is low, the reaction oil after the neutralization step contains glycerin and neutralization products that are not dissolved in the oil phase. Therefore, a step of separating these is carried out after neutralization. Examples of separation methods include filtration, static separation, and centrifugation, which can be easily performed. Among these, centrifugation is preferred because it allows simultaneous separation of the catalyst and unreacted glycerin.

[0029] With regard to the glyceride composition of the reaction oil after separation of the glycerin that is not dissolved in the oil phase and the neutralization product, from the viewpoint of improving physiologically active functions, the diacylglycerol content is preferably 15 to 60 mass%, more preferably 20 to 55 mass%, and even more preferably 25 to 55 mass%, the monoacylglycerol content is preferably 15 to 60 mass%, more preferably 20 to 55 mass%, and even more preferably 25 to 50 mass%, the triacylglycerol content is preferably 30 mass% or less, more preferably 20 mass% or less, and even more preferably 5 to 15 mass%, and the free fatty acid content is preferably 0.1 to 10 mass%, more preferably 0.1 to 7 mass%, and even more preferably 0.1 to 5 mass%.

[0030] The reaction oil after the transesterification reaction contains dissolved glycerin. It has been discovered that the inability to sufficiently reduce the by-product glycidol fatty acid esters in transesterified oils and fats is due to the glycerin dissolved in the reaction oil. Therefore, in the present invention, a process to reduce the glycerin dissolved in the reaction oil is then performed. Due to the need to reduce the glycerin concentration, the glycerin concentration in the reaction oil before the glycerin reduction process is preferably 1.5% by mass or more, more preferably 1.8% by mass or more, even more preferably 2.0% by mass or more, and even more preferably 2.5% by mass or more. Furthermore, due to the solubility limit of glycerin in oils and fats, the upper limit is preferably 9% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. The glycerin concentration in the reaction oil before the glycerin reduction process is preferably 1.5 to 9% by mass, more preferably 1.8 to 7% by mass, even more preferably 2.0 to 7% by mass, and even more preferably 2.5 to 5% by mass.

[0031] In the present invention, examples of the treatment for reducing the amount of glycerin dissolved in the reaction oil include, but are not limited to, distillation, water washing, deodorization, etc. The treatment for reducing the amount of glycerin dissolved in the reaction oil can be carried out by one or a combination of two or more treatments.

[0032] Examples of pressure reducing apparatuses used in the distillation process include batch simple distillation apparatuses, batch rectification apparatuses, continuous rectification apparatuses, flash evaporators, thin-film evaporators, etc. Among these, thin-film evaporators are preferred because they reduce equipment and operating costs, increase distillation capacity, and allow optimal selection of the distillation temperature. In the distillation process, distillation conditions for achieving the glycerin concentration of the deglycerinated oil after distillation within the concentration range described below can be set based on the vapor pressure curve. The distillation temperature is preferably 200°C or lower, more preferably 175°C or lower, and even more preferably 150°C or lower, from the viewpoints of not distilling off monoacylglycerols, diacylglycerols, and triacylglycerols and not subjecting the oil to thermal history. Furthermore, from the viewpoint of the efficiency of distilling off glycerin, the distillation temperature is preferably 20°C or higher, more preferably 40°C or higher, and even more preferably 60°C or higher. The distillation temperature is preferably 20 to 200°C, more preferably 40 to 175°C, and even more preferably 60 to 150°C. The degree of vacuum in the distillation treatment is preferably 5,000 Pa or less, more preferably 500 Pa or less, and even more preferably 50 Pa or less, from the viewpoint of not distilling off monoacylglycerol, diacylglycerol, and triacylglycerol and not giving thermal history, and is preferably 0.01 Pa or more, more preferably 0.1 Pa or more, and even more preferably 1 Pa or more, from the viewpoint of the efficiency of distilling off glycerin. The degree of vacuum is preferably 0.01 to 5,000 Pa, more preferably 0.1 to 500 Pa, and even more preferably 1 to 50 Pa.

[0033] The water washing treatment may be repeated multiple times, for example, two or three times. Examples of methods for contacting the reaction oil with water include a batch method in which the reaction oil and water are mixed and stirred, and then filtered. Prior to contacting the reaction oil with water, an aqueous solution containing a chelating agent such as citric acid may be added to and mixed with the reaction oil. This process is preferably carried out under a stream of inert gas such as nitrogen. Examples of water include tap water, purified water, distilled water, and ion-exchanged water. The amount of water used is preferably 1 to 500% by mass, more preferably 3 to 300% by mass, and even more preferably 5 to 200% by mass, relative to the reaction oil, from the viewpoint of sufficient removal of glycerin. The temperature of the water washing treatment is preferably 90°C or less, more preferably 20 to 90°C, and even more preferably 30 to 80°C, from the viewpoint of industrial productivity and sufficient contact between the reaction oil and water. From the same viewpoint, the time for the water washing treatment is preferably 0.1 to 120 minutes, more preferably 0.2 to 60 minutes, and even more preferably 0.3 to 30 minutes.

[0034] The deodorization treatment is basically carried out by reduced pressure steam distillation, and examples thereof include batch, semi-continuous, and continuous methods. The deodorization treatment involving contact with steam under reduced pressure can be carried out using a thin film deodorizer or a tray deodorizer alone, or by combining a deodorization treatment using a thin film deodorizer with a treatment using a tray deodorizer. In the present invention, a method using a thin film column or a tray deodorizer alone is preferred from the standpoint of equipment cost, flavor, and the like. The deodorization temperature is preferably 90 to 210°C, more preferably 100 to 200°C, and even more preferably 110 to 190°C, from the standpoint of reducing by-products in the adsorption treatment. The degree of vacuum in the deodorization treatment is preferably 20,000 Pa or less, more preferably 10,000 Pa or less, and even more preferably 5,000 Pa or less, from the viewpoint of not distilling off monoacylglycerol, diacylglycerol, and triacylglycerol and not giving thermal history, and is preferably 10 Pa or more, more preferably 50 Pa or more, and even more preferably 100 Pa or more, from the viewpoint of the efficiency of distilling off glycerin. The degree of vacuum is preferably 10 to 20,000 Pa, more preferably 50 to 10,000 Pa, and even more preferably 100 to 5,000 Pa. The amount of water vapor is preferably 0.5 to 20% / h, more preferably 1.0 to 10% / h, from the viewpoint of the efficiency of distilling off glycerin.

[0035] The glycerin concentration in the deglycerinized oil after the glycerin reduction treatment is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, even more preferably 2.0% by mass or less, still more preferably 1.5% by mass or less, still more preferably 1.0% by mass or less, still more preferably 0.7% by mass or less, and still more preferably 0.5% by mass or less, from the viewpoint of sufficiently reducing glycidol fatty acid esters. Furthermore, the glycerin concentration in the deglycerinized oil may be 0% by mass, but from the viewpoint of industrial productivity, it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. The glycerin concentration in the deglycerinated oil after the glycerin reduction treatment is preferably 3.0% by mass or less, more preferably 0.001 to 3.0% by mass, even more preferably 0.001 to 2.5% by mass, still more preferably 0.001 to 2.0% by mass, still more preferably 0.01 to 2.0% by mass, still more preferably 0.01 to 1.5% by mass, still more preferably 0.01 to 1.0% by mass, still more preferably 0.01 to 0.7% by mass, still more preferably 0.1 to 1.0% by mass, and still more preferably 0.1 to 0.5% by mass.

[0036] Furthermore, with regard to the glyceride composition of the deglycerinated oil after treatment to reduce glycerin, from the viewpoint of improving physiologically active functions, the diacylglycerol content is preferably 15 to 61% by mass, more preferably 20 to 56% by mass, and even more preferably 25 to 56% by mass; the triacylglycerol content is preferably 31% by mass or less, more preferably 21% by mass or less, and even more preferably 5 to 16% by mass; the monoacylglycerol content is preferably 15 to 61% by mass, more preferably 20 to 56% by mass, and even more preferably 25 to 51% by mass; and the free fatty acid content is preferably 10% by mass or less, preferably 0.1 to 10% by mass, more preferably 0.1 to 7% by mass, and even more preferably 0.1 to 5% by mass.

[0037] Next, the deglycerinated oil is brought into contact with an adsorbent. Porous adsorbents are preferred as adsorbents, and examples thereof include activated carbon, silicon dioxide, and solid acid adsorbents. Examples of solid acid adsorbents include acid clay, activated clay, activated alumina, silica gel, silica-alumina, and aluminum silicate. These adsorbents can be used alone or in combination. Of these, solid acid adsorbents are preferred, with acid clay and activated clay being particularly preferred, in terms of reducing the content of by-products and improving flavor and color.

[0038] Both acid clay and activated clay contain SiO2, Al2O3, Fe2O3, CaO, MgO, etc. as general chemical components, but it is preferable that the SiO2 / Al2O3 ratio is 3 to 12, especially 4 to 10. Furthermore, a composition containing 1 to 5% Fe2O3, 0 to 1.5% CaO, and 1 to 7% MgO is preferred.

[0039] Activated clay is a compound made by treating naturally occurring acid clay (montmorillonite clay) with a mineral acid such as sulfuric acid, and has a porous structure with a large specific surface area and adsorption capacity. It is known that further acid treatment of acid clay changes the specific surface area, improving the decolorizing ability and changing the physical properties. The specific surface area of ​​acid clay or activated clay varies depending on the degree of acid treatment, but is generally between 50 and 400 m 2 / g, and the pH (5% suspension) is preferably 2.5 to 9, particularly preferably 3 to 7. As the acid clay, for example, commercially available products such as Mizuka Ace #20 and Mizuka Ace #400 (both manufactured by Mizusawa Industrial Chemicals Co., Ltd.) can be used, and as the activated clay, for example, commercially available products such as Galleon Earth V2R, Galleon Earth NV, and Galleon Earth GSF (all manufactured by Mizusawa Industrial Chemicals Co., Ltd.) can be used.

[0040] In this treatment, perlite, silicon dioxide, diatomaceous earth, etc. may be added as a filter aid in order to achieve a high filtration rate and good productivity.

[0041] The amount of adsorbent used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, based on the deglycerinated oil, from the viewpoint of sufficiently reducing glycidol fatty acid esters, and is preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of industrial productivity. The amount of adsorbent used is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, and even more preferably 0.5 to 3% by mass.

[0042] The contact temperature between the deglycerinated oil and the adsorbent is preferably 20°C or higher, more preferably 40°C or higher, and even more preferably 60°C or higher, from the viewpoint of sufficiently reducing glycidol fatty acid esters, and is preferably 150°C or lower, more preferably 135°C or lower, and even more preferably 120°C or lower, from the viewpoint of suppressing oxidation and industrial productivity.

[0043] The contact time is preferably 2 minutes or more, more preferably 5 minutes or more, and even more preferably 10 minutes or more from the viewpoint of sufficiently reducing the glycidol fatty acid esters, and is preferably 60 minutes or less, more preferably 50 minutes or less, and even more preferably 40 minutes or less from the viewpoint of suppressing oxidation and industrial productivity.

[0044] When a reaction oil obtained by transesterification of a fat or oil with glycerin is commercialized as an edible fat or oil, it is preferable to reduce the monoacylglycerol content in the reaction oil in order to reduce the refining load and improve the flavor, since monoacylglycerol is easily emulsified and has a unique flavor. By increasing the contact time between the deglycerinated oil and the adsorbent, transesterified fat or oil rich in diacylglycerol can be produced while reducing monoacylglycerol, and the purity of diacylglycerol in the product [diacylglycerol / (diacylglycerol+triacylglycerol)×100] can be increased. Therefore, from the viewpoints of providing an edible oil or fat with a high physiological effect due to diacylglycerol, reducing the refining load, and improving flavor, the contact time between the deglycerinated oil and the adsorbent is preferably 20 minutes or more, more preferably 30 minutes or more, even more preferably 45 minutes or more, and even more preferably 60 minutes or more, and from the viewpoints of oxidation inhibition and industrial productivity, it is preferably 10 hours or less, more preferably 5 hours or less, and even more preferably 3 hours or less. The contact time between the deglycerinated oil and the adsorbent is preferably 20 minutes to 10 hours, more preferably 30 minutes to 10 hours, even more preferably 45 minutes to 5 hours, and even more preferably 60 minutes to 3 hours.

[0045] The pressure may be reduced or normal pressure, but reduced pressure is preferred from the viewpoint of suppressing oxidation of the oils and fats. In the case of normal pressure, a nitrogen atmosphere is preferred. The specific pressure is preferably 100 to 13,000 Pa, more preferably 500 to 10,000 Pa, and even more preferably 1,000 to 5,000 Pa.

[0046] After contacting the deglycerinated oil with the adsorbent, the adsorbent is separated by filtration, which is preferably performed by suction filtration, pressure filtration, centrifugal filtration, or the like, and a filter used in the decolorization process for fats and oils can be used.

[0047] The adsorbent-treated oil after contacting the deglycerinated oil with an adsorbent maintains the glyceride composition of the reaction oil. From the viewpoint of improving physiological activity, the glyceride composition of the adsorbent-treated oil of the present invention preferably has a diacylglycerol content of 17 to 71% by mass, more preferably 22 to 66% by mass, and even more preferably 27 to 66% by mass. The triacylglycerol content is preferably 31% by mass or less, more preferably 21% by mass or less, and even more preferably 5 to 16% by mass. The monoacylglycerol content is preferably 13 to 59% by mass, more preferably 18 to 54% by mass, and even more preferably 23 to 49% by mass.

[0048] Furthermore, when the treatment of contacting the deglycerinated oil with the adsorbent is carried out for 20 minutes or longer, the diacylglycerol content in the adsorbent-treated oil increases. Regarding the glyceride composition of the adsorbent-treated oil after the adsorbent contact treatment for 20 minutes or longer, from the viewpoint of improving physiological activity, the diacylglycerol content is preferably 18 to 72 mass%, more preferably 23 to 67 mass%, and even more preferably 28 to 67 mass%, the triacylglycerol content is preferably 31 mass% or less, more preferably 21 mass% or less, and even more preferably 5 to 16 mass%, and the monoacylglycerol content is preferably 12 to 58 mass%, more preferably 17 to 53 mass%, and even more preferably 22 to 48 mass%.

[0049] As a result of the treatment of the present invention, interesterified oils and fats can be obtained with a small content of glycidol fatty acid esters as by-products. The content of glycidol fatty acid esters can be determined by measuring the total amount of 3-chloropropane-1,2-diol esters (3-MCPD-E), 3-chloropropane-1,2-diol (3-MCPD), 3-chloropropane-1,2-diol esters (3-MCPD-E), glycidol, and fatty acid esters of glycidol (MCPD-FS). 3-MCPD-E can be measured by the method described in German Society for Lipid Research Standard Method C-VI 18(10) (DGF Standard Methods 2010 (16. Supplement), C-VI 18(10), "Fatty-acid-bound 3-chloropropane-1,2-diol (3-MCPD) and 2,3-epoxi-propane-1-ol (glycidol)"). In the present invention, the value obtained by the standard method, Assay B, is used as the 3-MCPD-E content. MCPD-FS can be measured by the method described in the German Society for Lipid Research (hereinafter also referred to as "DGF") Standard Method C-III 18(09) (DGF Standard Methods 2009 (14. Supplement), C-III 18(09), "Ester-bound 3-chloropropane-1,2-diol (3-MCPD esters) and glycidol (glycidyl esters)"). In the present invention, to quantify glycidol esters, Option A described in Standard Method 7.1 ("7.1 Option A: Determination of the sum of ester-bound 3-MCPD and glycidol") is used. Details are described in the Examples.

[0050] The content of glycidol fatty acid ester in the interesterified oil of the present invention is preferably 0.45 mg / kg or less, more preferably 0.4 mg / kg or less, even more preferably 0.35 mg / kg or less, from the viewpoint of safety of the obtained glyceride product, and is preferably 0.00 mg / kg, but from the viewpoint of industrial productivity, it is preferably 0.01 mg / kg or more, more preferably 0.03 mg / kg or more, even more preferably 0.06 mg / kg or more. The content of glycidol fatty acid ester in the interesterified oil is preferably 0.01 to 0.45 mg / kg, more preferably 0.03 to 0.4 mg / kg, even more preferably 0.06 to 0.35 mg / kg.

[0051] In addition, in interesterified oils and fats where the treatment of contacting the deglycerinized oil with an adsorbent is carried out for 20 minutes or more, the increase in diacylglycerol from before the treatment of contacting the deglycerinized oil with an adsorbent to after the treatment of contacting the deglycerinized oil with an adsorbent is preferably 3.5% by mass or more, more preferably 4.0% by mass or more, even more preferably 5.0% by mass or more, and even more preferably 6.0% by mass or more, in terms of enhancing physiological effects, and from the viewpoint of industrial productivity, it is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. In interesterified oils and fats, the increase in diacylglycerol from before the treatment of contacting the deglycerinized oil with an adsorbent to after the treatment of contacting the deglycerinized oil with an adsorbent is preferably 3.5 to 20% by mass, more preferably 4.0 to 15% by mass, even more preferably 5.0 to 10% by mass, and even more preferably 6.0 to 10% by mass.

[0052] The interesterified oils and fats obtained by the method of the present invention are rich in diacylglycerol and have the same glyceride composition as that of the adsorbent-treated oil described above. If necessary, the diacylglycerol may be concentrated or a purification process other than that described above may be carried out for ordinary oils and fats, and the oils and fats can be used in the same way as ordinary edible oils and fats.

[0053] In relation to the above-described embodiment, the present invention further discloses the following method for producing interesterified fats and oils.

[0054] <1> A method for producing interesterified fats and oils, which comprises transesterifying fats and oils with glycerin, followed by a treatment to reduce the amount of glycerin dissolved in the reaction oil, and then contacting the deglycerinated oil with an adsorbent.

[0055] <2> The method for producing interesterified oils and fats according to <1>, wherein the glycerin concentration in the deglycerinized oil after treatment to reduce the amount of glycerin dissolved in the reaction oil is 3.0% by mass or less. <3> The method for producing interesterified oils and fats according to <1> or <2>, wherein the ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] during the interesterification reaction of the oil or fat with glycerin is 2.0 or less. <4> The method for producing interesterified oils and fats according to any one of <1> to <3>, wherein the contact temperature between the deglycerinized oil and the adsorbent is 20°C or higher. <5> The method for producing interesterified oils and fats according to any one of <1> to <4>, wherein the adsorbent is one or more selected from solid acid adsorbents. <6> The method for producing interesterified oils and fats according to any one of <1> to <5>, wherein the adsorbent is one or more selected from acid clay and activated clay. <7> The method for producing transesterified oils and fats according to any one of <1> to <6>, wherein the adsorbent is brought into contact with the deglycerinized oil in an amount of 10% by mass or less. <8> The method for producing transesterified oils and fats according to any one of <1> to <7>, wherein the glycerin concentration in the reaction oil before the treatment to reduce glycerin is 1.5 to 9% by mass. <9> The method for producing transesterified oils and fats according to any one of <1> to <8>, wherein the content of glycidol fatty acid esters in the transesterified oils and fats is 0.01 to 0.45 mg / kg. <10> The method for producing transesterified oils and fats according to any one of <1> to <9>, wherein the treatment of contacting the deglycerinized oil with the adsorbent is carried out for 20 minutes or more. <11> The method for producing transesterified oils and fats according to <10>, wherein the increase in diacylglycerol in the transesterified oils and fats after the treatment of contacting the deglycerinized oil with the adsorbent is 3.5 to 20% by mass from before the treatment of contacting the deglycerinized oil with the adsorbent. <12> The method for producing interesterified oils and fats according to any one of <1> to <11>, wherein the adsorbent-treated oil after the treatment of bringing the deglycerinized oil into contact with the adsorbent has a diacylglycerol content of 17 to 71% by mass. <13> The method for producing interesterified oils and fats according to any one of <1> to <12>, wherein the adsorbent-treated oil after the treatment of bringing the deglycerinized oil into contact with the adsorbent has a monoacylglycerol content of 13 to 59% by mass.<14> A method for producing interesterified oils and fats according to any one of <1> to <13>, wherein the total content of fatty acids having a carbon chain length of 18 or more and three or more double bonds among the fatty acids constituting the oils and fats is 15 to 99% by mass. <15> A method for producing interesterified oils and fats according to any one of <1> to <14>, wherein the glycerin concentration in the reaction oil before the glycerin reduction treatment is 1.8 to 7% by mass and the glycerin concentration in the deglycerinated oil is 0.001 to 2.0% by mass. <15> A method for producing interesterified oils and fats according to any one of <1> to <14>, wherein the deglycerinated oil having a glycerin concentration of 2.0% by mass or less is contacted with an adsorbent in an amount of 0.1 to 10% by mass. <16> A method for producing interesterified oils and fats according to any one of <1> to <15>, wherein the content of glycidol fatty acid esters in the interesterified oils and fats is 0.03 to 0.4 mg / kg and the content of diacylglycerol is 22 to 66% by mass. <17> The method for producing interesterified fats and oils according to any one of <1> to <16>, wherein, in the interesterified fats and oils, the increase in diacylglycerol from before the treatment of bringing the deglycerinized oil into contact with the adsorbent is 4.0 to 15% by mass after the treatment of bringing the deglycerinized oil into contact with the adsorbent, and the diacylglycerol content in the interesterified fats and oils is 23 to 67% by mass. <18> The method for producing interesterified fats and oils according to any one of <1> to <17>, wherein, when the oils and fats are subjected to an interesterification reaction with glycerin, the ratio of the number of moles of fatty acid groups to the number of moles of glycerin groups [FA / GLY] is 0.60 to 2.0.

[0056] In the following examples, "%" means "% by mass".

[0057] [Analysis Method] (i) Measurement of Glyceride Composition Approximately 10 mg of fat or oil and 0.5 mL of a trimethylsilylation agent ("Silylation Agent TH", manufactured by Kanto Chemical) were placed in a glass sample bottle, sealed, and heated at 70°C for 15 minutes. 1.5 mL of water and 1.5 mL of hexane were added to the bottle and the mixture was shaken. After allowing to stand, the upper layer was subjected to gas chromatography (GC) to analyze the glyceride composition.

[0058] (ii) Measurement of MCPD-FS (based on the German Society for Lipid Research (DGF) standard method C-III 18(09) option A) Approximately 100 mg of a fat or oil sample was weighed into a lidded test tube, and 50 μL of the internal standard (3-MCPD-d5 / t-butyl methyl ether), 500 μL of a t-butyl methyl ether / ethyl acetate mixed solution (volume ratio 8:2), and 1 mL of 0.5 N sodium methoxide were added and stirred, followed by standing for 10 minutes. 3 mL of hexane and 3 mL of a 3.3% acetic acid / 20% sodium chloride aqueous solution were added and stirred, and the upper layer was removed. Another 3 mL of hexane was added and stirred, followed by removing the upper layer. 250 μL of a mixture of 1 g of phenylboronic acid and 4 mL of 95% acetone was added and stirred, followed by sealing and heating at 80°C for 20 minutes. 3 mL of hexane was added to this and stirred, and the upper layer was subjected to gas chromatography-mass spectrometry (GC-MS) to quantify the amount of glycidol fatty acid esters.

[0059] (iii) Measurement of 3-MCPD-E (based on the German Society for Lipid Research (DGF) standard method C-VI 18(10) assay B) Approximately 100 mg of fat or oil sample was weighed into a lidded test tube, and 100 μL of the internal standard (3-MCPD-d5-dipalmitate / t-butyl methyl ether), 100 μL of t-butyl methyl ether, and 200 μL of 0.5 N sodium methoxide were added and stirred, followed by standing for 5 minutes. 600 μL of isohexane and 600 μL of an 8.75% sulfuric acid / 60% aqueous sodium bromide solution were added and stirred, and the upper layer was removed. Another 600 μL of isohexane was added and stirred, followed by removing the upper layer. The lower layer was extracted three times with 600 μL of a diethyl ether / ethyl acetate mixed solution (volume ratio 3:2), to which 100 μL of a saturated phenylboronic acid / diethyl ether solution was added and stirred. The organic solvent was distilled off under a nitrogen stream, and then 500 μL of isooctane was added to the residue, followed by stirring and subjecting the mixture to gas chromatography-mass spectrometry (GC-MS) to quantify the amount of 3-MCPD-E.

[0060] The values ​​determined in (ii) and (iii) above were converted into the content of glycidol fatty acid ester (GE) by the following formula (2): GE [mg as G / kg] = (MCPD-FS [mg / kg] - 3 - MCPD-E [mg / kg]) × 74 / 110 (2)

[0061] [Preparation of Reaction Oil A] The reaction raw materials, fats and oils and glycerin shown in Table 1, were placed in a 5L four-neck flask equipped with a stirring blade (90mm x 25mm). While stirring at 400 r / min, the mixture was dehydrated under reduced pressure at 80°C and 400 Pa for 30 minutes. Then, nitrogen was introduced to return the pressure to normal, and while circulating nitrogen in the space inside the flask, the temperature was raised to the reaction temperature of 150°C at a heating rate of 1°C / min. Next, calcium hydroxide was added as a catalyst in an amount of 0.10% by mass relative to the raw materials, and a transesterification reaction was carried out at a temperature of 150°C and normal pressure (nitrogen flow). Five hours after the start of the reaction, the mixture was cooled to 90°C, and phosphoric acid was added as a neutralizing agent so that the molar ratio to the catalyst was 1.5. The mixture was then stirred for 30 minutes to neutralize. The mixture was then cooled to 60°C and centrifuged at 3000 r / min for 10 minutes, and the precipitated glycerin and catalyst were removed to obtain reaction oil a. The analytical results of reaction oil a are shown in Table 1.

[0062] [Preparation of Reaction Oil b] The reaction raw materials, fats and oils and glycerin shown in Table 1, were placed in a 1 L four-neck flask equipped with a stirring blade (90 mm x 25 mm). The same treatment as for reaction oil a was carried out to obtain reaction oil b, except that the catalyst was added after the reaction temperature reached 210°C and the reaction time was set to 1 hour. The analytical results of reaction oil b are shown in Table 1.

[0063] [Preparation of Reaction Oil c] The reaction raw materials, fats and oils and glycerin shown in Table 1, were placed in a 2 L four-neck flask equipped with a stirring blade (90 mm x 25 mm). The same treatment as for reaction oil a was carried out, except that the amount of catalyst added was 0.05% by mass relative to the raw materials, to obtain reaction oil c. The analytical results of reaction oil c are shown in Table 1.

[0064] [Preparation of Reaction Oil d] The reaction raw materials, fats and oils and glycerin shown in Table 1, were placed in a 2 L four-neck flask equipped with a stirring blade (90 mm x 25 mm). The same treatment as for reaction oil a was carried out, except that the amount of catalyst added was 0.15% by mass relative to the raw materials, to obtain reaction oil d. The analytical results of reaction oil d are shown in Table 1.

[0065] [Preparation of Reaction Oil e] Reaction oil e was obtained in the same manner as reaction oil c, except that sodium methoxide was used as the catalyst and added in an amount of 0.22 mass% relative to the raw material. The analysis results of reaction oil e are shown in Table 1.

[0066] [Preparation of Reaction Oil f] The reaction raw materials, fats and oils and glycerin shown in Table 1, were placed in a 5 L four-neck flask equipped with a stirring blade (90 mm x 25 mm). The catalyst was added in an amount of 0.20% by mass relative to the raw materials, and the reaction temperature was 160°C, and a transesterification reaction was carried out. Four hours after the start of the reaction, the mixture was cooled to 60°C and centrifuged at 5000 r / min for 10 minutes to remove the settled glycerin, yielding a pre-neutralization oil. This reaction procedure was repeated twice to obtain a mixed pre-neutralization oil. 300 g of the pre-neutralization oil was placed in a 500 mL four-neck flask equipped with a stirring blade (60 mm x 20 mm). The mixture was heated to 90°C while stirring at 400 r / min. Then, 0.88 g of 85.8% phosphoric acid (moles of phosphoric acid / moles of calcium hydroxide = 0.90) was added, and the mixture was neutralized by stirring for 30 minutes. Thereafter, the mixture was cooled to 60° C. and centrifuged at 5000 r / min for 10 minutes to remove the settled catalyst, thereby obtaining a reaction oil f. The analytical results of the reaction oil f are shown in Table 1.

[0067] [Preparation of Reaction Oil G] Reaction oil g was obtained by neutralization treatment under the same conditions as reaction oil f, except that 0.98 g of 85.8% phosphoric acid (moles of phosphoric acid / moles of calcium hydroxide = 1.00) was added. The analytical results of reaction oil g are shown in Table 1.

[0068]

[0069] Example 1: Wiped film evaporator (Kobe Eco Solutions Co., Ltd., Model 2-03, inner diameter 5 cm, heat transfer area 0.03 m) ２) using a thin film distillation reactor, reaction oil a was subjected to thin film distillation. The operation was carried out under conditions of a heater temperature setting of 100 ° C, a pressure of 1 to 2 Pa, and a flow rate of 150 g / h, to obtain thin film distilled oil a. 150 g of thin film distilled oil a was placed in a 300 mL four-neck flask equipped with a stirring blade (60 mm x 20 mm). While stirring at 400 r / min, the mixture was dehydrated under reduced pressure at 80 ° C and 400 Pa for 30 minutes. The mixture was then heated to 110 ° C, and 1.5 g of activated clay (Galleon Earth V2R: manufactured by Mizusawa Industrial Chemicals, Ltd.) was added, followed by adsorbent treatment at normal pressure. After 10, 20, 30, 60, 90, and 120 minutes, the mixture was sampled, cooled to 70 ° C, and the activated clay was filtered off to obtain adsorbent-treated oils a, b, c, d, e, and f. The composition of thin-film distilled oil a and the GE content after 30 minutes of adsorbent treatment are shown in Table 2, and the GE content and glyceride composition of adsorbent-treated oils a to f are shown in Table 3.

[0070] The results are shown in Table 2.

[0071] [Example 3] Except for changing the temperature of the adsorbent treatment to 80°C and the sampling time to 30 minutes, activated clay treatment was carried out in the same manner as in Example 1 to obtain adsorbent-treated oil. The results are shown in Table 2.

[0072] Comparative Example 1 Treated oil was obtained in the same manner as in Example 1, except that activated clay was not added and the sampling time was 30 minutes. The results are shown in Table 2.

[0073] Example 4: Reaction oil a and 0.5% by mass of a 50% aqueous citric acid solution were added to a 1 L four-neck flask equipped with a stirring blade (90 mm x 25 mm). The mixture was stirred at 70°C for 30 minutes at 300 r / min under a nitrogen atmosphere. Distilled water (100% by mass relative to reaction oil a) was then added. The mixture was stirred at 70°C for 10 minutes at 300 r / min under a nitrogen atmosphere, and centrifuged at 3000 r / min for 10 minutes to remove the settled aqueous phase. This water-washing procedure was repeated three times, followed by dehydration at 70°C for 30 minutes at 300 r / min under a pressure of 400 Pa or less and returning to normal pressure with nitrogen to obtain water-washed oil a. Activated clay treatment was performed in the same manner as in Example 1, except that water-washed oil a was used and the sampling time was 30 minutes, to obtain an adsorbent-treated oil. The composition of water-washed oil a and the results of the adsorbent treatment are shown in Table 2.

[0074] Comparative Example 2 The activated clay treatment was carried out in the same manner as in Example 1, except that the raw oil to be treated was reaction oil a and the sampling time was 30 minutes, to obtain an adsorbent-treated oil. The results are shown in Table 2.

[0075] [Example 5] Reaction oil b was thin-film distilled under the same conditions as in Example 1 to obtain thin-film distilled oil b. Next, thin-film distilled oil b was treated with activated clay in the same manner as in Example 1, and sampled after 30 minutes to obtain adsorbent-treated oil. The composition of thin-film distilled oil b and the results of the adsorbent treatment are shown in Table 2.

[0076] [Example 6] Reaction oil c was thin-film distilled under the same conditions as in Example 1 to obtain thin-film distilled oil c. The glycerin concentration of thin-film distilled oil c at this time was 0.3%. Glycerin (manufactured by Kao) was added to thin-film distilled oil c and mixed to obtain glycerin-adjusted oil a, in which the glycerin concentration was adjusted to 0.6%. Next, activated clay treatment was performed in the same manner as in Example 1, and sampling was performed after 30 minutes to obtain adsorbent-treated oil. The composition of glycerin-adjusted oil a and the results of the adsorbent treatment are shown in Table 2.

[0077] Example 7 Glycerin (Kao) was added to thin-film distilled oil c to adjust the glycerin concentration to 1.0%, to obtain glycerin-adjusted oil b. Subsequently, activated clay treatment was carried out in the same manner as in Example 1, and after 30 minutes, sampling was carried out to obtain adsorbent-treated oil. The composition of glycerin-adjusted oil b and the results of the adsorbent treatment are shown in Table 2.

[0078] [Example 8] Reaction oil d was subjected to thin film distillation under the same conditions as in Example 1 to obtain thin film distilled oil d. Next, thin film distilled oil d was treated with activated clay in the same manner as in Example 1, and sampled after 30 minutes to obtain adsorbent-treated oil. The composition of thin film distilled oil d and the results of the adsorbent-treated oil are shown in Table 2.

[0079] [Example 9] Reaction oil f was treated under the same conditions as in Example 1, except that the flow rate of thin film distillation was 100 g / h, to obtain thin film distilled oil f. Next, thin film distilled oil f was treated with activated clay in the same manner as in Example 1, and sampled after 30 minutes to obtain adsorbent-treated oil. The composition of thin film distilled oil f and the results of the adsorbent-treated oil are shown in Table 2.

[0080] [Example 10] Reaction oil g was treated with acid and washed with water under the same conditions as in Example 4 to obtain water-washed oil b. Next, water-washed oil b was treated with activated clay in the same manner as in Example 1, and sampled after 30 minutes to obtain adsorbent-treated oil. The composition of water-washed oil b and the results of the adsorbent-treated oil are shown in Table 2.

[0081] [Example 11] Reaction oil e was subjected to thin film distillation under the same conditions as in Example 1 to obtain thin film distilled oil e. Next, thin film distilled oil e was subjected to the same activated clay treatment as in Example 1, and after 30 minutes, it was sampled to obtain adsorbent-treated oil. The composition of thin film distilled oil e and the results of the adsorbent treatment are shown in Table 4.

[0082] Comparative Example 3 Reaction oil e was treated with activated clay in the same manner as in Example 1, and sampled after 30 minutes to obtain adsorbent-treated oil. The results are shown in Table 4.

[0083]

[0084]

[0085]

[0086] As is clear from Tables 2 to 4, regardless of the concentration of glycerin dissolved in the reaction oil due to different reaction conditions, it was found that when the reaction oil after the transesterification reaction was distilled or washed with water to reduce the glycerin concentration and then subjected to adsorbent treatment, an oil with a low concentration of glycidol fatty acid esters in the adsorbent-treated oil was obtained (Examples 1 to 5, 8 to 11). Furthermore, it was found that neutralization with a neutralizing agent equimolar to the added chemical catalyst after the transesterification reaction resulted in an oil with an even lower concentration of glycidol fatty acid esters (Examples 9 to 10). On the other hand, it was found that when the reaction oil was directly treated with an adsorbent, or when an adsorbent such as activated clay was not added even after deglycerinization, the glycidol fatty acid esters could not be reduced (Comparative Examples 1, 2, and 3). Furthermore, when glycerin was added to thin-film distilled oil obtained by distilling the reaction oil to adjust the glycerin concentration and then subjected to adsorbent treatment, it was found that the lower the glycerin concentration of the oil before adsorbent treatment, the lower the oil with a low concentration of glycidol fatty acid esters (Examples 6 and 7).

[0087] Example 12 Activated clay treatment was carried out in the same manner as in Example 1, except that the amount of activated clay added was 4.5 g and the sampling time was 120 minutes, to obtain adsorbent-treated oil.

[0088] Example 13 Activated clay treatment was carried out in the same manner as in Example 1, except that the temperature for the adsorbent treatment was 80° C. and the sampling time was 120 minutes, to obtain adsorbent-treated oil.

[0089] Comparative Example 4 Treated oil was obtained by carrying out the same activated clay treatment as in Example 1, except that no activated clay was added and the sampling time was 120 minutes.

[0090] The results after 120 minutes of adsorbent treatment in Example 1, as well as the results in Examples 12 and 13 and Comparative Example 4, are shown in Table 5.

[0091] Example 14: Reaction oil a and 50% citric acid aqueous solution (0.5% by mass relative to reaction oil a) were added to a 1 L four-neck flask equipped with a stirring blade (90 mm x 25 mm), and the mixture was stirred at 70 ° C for 30 minutes at 300 r / min under a nitrogen atmosphere. Distilled water (100% by mass relative to reaction oil a) was then added, and the mixture was stirred at 70 ° C for 10 minutes at 300 r / min under a nitrogen atmosphere, and centrifuged at 3000 r / min for 10 minutes to remove the settled aqueous phase. This water-washing operation was repeated three times, and the mixture was dehydrated at 70 ° C for 30 minutes at 300 r / min under a pressure of 400 Pa or less and returned to normal pressure with nitrogen to obtain water-washed oil a. The activated clay treatment was performed in the same manner as in Example 1, except that water-washed oil a was used and the sampling time was 120 minutes, and an adsorbent-treated oil was obtained. The compositions of water-washed oil a and adsorbent-treated oil are shown in Table 5.

[0092] Comparative Example 5 The activated clay treatment was carried out in the same manner as in Example 1, except that the raw material oil to be treated was reaction oil a and the sampling time was 120 minutes, to obtain an adsorbent-treated oil. The results are shown in Table 5.

[0093] [Example 15] Reaction oil b was subjected to thin film distillation under the same conditions as in Example 1 to obtain thin film distilled oil b. Next, the same activated clay treatment as in Example 1 was carried out, and after 120 minutes, sampling was carried out to obtain adsorbent-treated oil. The compositions of thin film distilled oil b and adsorbent-treated oil are shown in Table 5.

[0094] [Example 16] Reaction oil e was subjected to thin film distillation under the same conditions as in Example 1 to obtain thin film distilled oil e. Next, thin film distilled oil e was subjected to the same activated clay treatment as in Example 1, and after 120 minutes, it was sampled to obtain adsorbent-treated oil. The compositions of thin film distilled oil e and adsorbent-treated oil are shown in Table 5.

[0095] Comparative Example 6 An adsorbent-treated oil was obtained by the same activated clay treatment as in Example 1, except that the raw material oil to be treated was reaction oil e and the sampling time was 120 minutes. The results are shown in Table 5.

[0096] [Example 17] Reaction oil c was thin-film distilled under the same conditions as in Example 1 to obtain thin-film distilled oil c. The glycerin concentration of thin-film distilled oil c was 0.3%. Next, glycerin (manufactured by Kao) was added to thin-film distilled oil c and mixed to obtain glycerin-adjusted oil a, in which the glycerin concentration was adjusted to 0.6%. Next, the same activated clay treatment as in Example 1 was carried out, and after 120 minutes, sampling was carried out to obtain adsorbent-treated oil. The compositions of glycerin-adjusted oil a and adsorbent-treated oil are shown in Table 5.

[0097] Example 18 Glycerin (Kao) was added to and mixed with the thin-film distilled oil c to obtain glycerin-adjusted oil b, in which the glycerin content was adjusted to 1.0%. The same activated clay treatment as in Example 1 was then carried out, and after 120 minutes, the oil was sampled to obtain adsorbent-treated oil. The compositions of glycerin-adjusted oil b and the adsorbent-treated oil are shown in Table 5.

[0098] Example 19 Glycerin (Kao) was added to and mixed with the thin-film distilled oil c to adjust the glycerin concentration to 1.6%, thereby obtaining glycerin-adjusted oil c. Subsequently, the same activated clay treatment as in Example 1 was carried out, and after 120 minutes, sampling was carried out to obtain adsorbent-treated oil. The compositions of glycerin-adjusted oil c and the adsorbent-treated oil are shown in Table 5.

[0099] [Example 20] 200 g of reaction oil a was placed in a Claisen flask and deodorized for 1 hour under conditions of a temperature of 130°C, a pressure of 400 Pa, and a steam flow rate of 3% / h to obtain deodorized oil a. Next, activated clay treatment was carried out in the same manner as in Example 1, and after 120 minutes, sampling was carried out to obtain adsorbent-treated oil. The compositions of deodorized oil a and adsorbent-treated oil are shown in Table 5.

[0100] Example 21: 200 g of reaction oil a was placed in a Claisen flask and deodorized for 1 hour under conditions of a temperature of 200°C, a pressure of 400 Pa, and a steam flow rate of 3% / h to obtain deodorized oil b. Subsequently, the same activated clay treatment as in Example 1 was carried out, and after 120 minutes, sampling was carried out to obtain adsorbent-treated oil. The compositions of deodorized oil b and adsorbent-treated oil are shown in Table 5.

[0101] [Example 22] Reaction oil d was thin-film distilled under the same conditions as in Example 1 to obtain thin-film distilled oil d. Next, thin-film distilled oil d was treated with activated clay in the same manner as in Example 1, and sampled after 120 minutes to obtain adsorbent-treated oil. The composition of thin-film distilled oil d and the results of the adsorbent-treated oil are shown in Table 5.

[0102] Comparative Example 7 An adsorbent-treated oil was obtained by the same activated clay treatment as in Example 1, except that the raw material oil to be treated was reaction oil d and the sampling time was 120 minutes. The results are shown in Table 5.

[0103]

[0104] As is clear from Table 5, regardless of the concentration of glycerin dissolved in the reaction oil due to different reaction conditions, if the reaction oil after the transesterification reaction was distilled, washed with water, or deodorized to reduce the glycerin concentration, and then subjected to prolonged adsorbent treatment, not only was the concentration of glycidol fatty acid esters in the adsorbent-treated oil low, but triacylglycerols remained unchanged, monoacylglycerols decreased, and diacylglycerols increased efficiently (Examples 1, 12-22). On the other hand, when the reaction oil was treated with an adsorbent directly, or when activated clay was not added even after deglycerin treatment, no change in the glyceride composition was observed (Comparative Examples 4-7). Furthermore, glycerin was added to thin-film distilled oil obtained by distillation of the reaction oil to adjust the glycerin concentration, and the adsorbent treatment was performed. As a result, it was found that the lower the glycerin concentration of the oil before adsorbent treatment, the greater the increase in diacylglycerol during adsorbent treatment (Examples 17-19).

Claims

1. A method for producing transesterified oil and fat, which comprises performing a treatment to reduce glycerin dissolved in the reaction oil after subjecting oil and fat and glycerin to a transesterification reaction, and then performing a treatment of bringing an adsorbent into contact with the deglycerinated oil.

2. The method for producing transesterified oil and fat according to claim 1, wherein the glycerin concentration in the deglycerinated oil after the treatment for reducing glycerin dissolved in the reaction oil is 3.0% by mass or less.

3. The method for producing transesterified oil and fat according to claim 1 or 2, wherein the ratio [FA / GLY] of the number of moles of fatty acid groups to the number of moles of glycerin groups during the transesterification reaction between oil and fat and glycerin is 2.0 or less.

4. The method for producing transesterified oil and fat according to any one of claims 1 to 3, wherein the adsorbent is one or more selected from solid acid adsorbents.

5. The method for producing transesterified oil and fat according to any one of claims 1 to 4, wherein the adsorbent is one or more selected from acid clay and activated clay.

6. The method for producing transesterified oil and fat according to any one of claims 1 to 5, wherein the adsorbent is brought into contact with the deglycerinated oil in an amount of 10% by mass or less.

7. The method for producing transesterified oil and fat according to any one of claims 1 to 6, wherein the treatment of bringing the adsorbent into contact with the deglycerinated oil is performed for 20 minutes or more.

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