Production method for transesterified oil / fat

Abstract

To provide a method for producing a transesterified oil / fat rich in diacylglycerol while reducing monoacylglycerol.SOLUTION: 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 for at least 20 minutes.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing transesterified oil and fat rich in diacylglycerol.

Background Art

[0002] Diacylglycerol is used in various industrial fields such as foods and cosmetics. Generally, diacylglycerol is produced by an esterification reaction between glycerin and a fatty acid or a glycerolysis reaction (transesterification reaction) between glycerin and oil and fat. These production methods are roughly classified into a chemical method using a chemical catalyst such as a hydroxide or an alkoxide of an alkali metal or an alkaline earth metal and an enzymatic method using an enzyme such as lipase. After the esterification reaction or the transesterification reaction, diacylglycerol is decolorized by adding activated clay or the like and deodorized by contacting with steam under high temperature and reduced pressure in order to obtain a quality suitable for food use (for example, Patent Documents 1 to 2). The glycerolysis method can produce diacylglycerol with fewer steps compared to the esterification method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the glycerolysis method, in order to increase the purity of diacylglycerol [diacylglycerol / (diacylglycerol + triacylglycerol) × 100], it is necessary to lower the ratio of oil and fat to glycerin in the reaction raw materials. However, it is common general knowledge that when this ratio is lowered, a large amount of monoacylglycerol is produced when the equilibrium composition is reached. Since monoacylglycerol is easily emulsified, has a high purification load, and has a specific flavor, it is desirable to reduce monoacylglycerol in the transesterified oil (hereinafter, also simply referred to as "reaction oil"). Accordingly, an object of the present invention is to provide a method for producing a transesterified oil and fat rich in diacylglycerol while reducing monoacylglycerol.

Means for Solving the Problems

[0005] In view of the above problems, the present inventor conducted intensive research and found that after the transesterification reaction, a treatment for reducing glycerin dissolved in the reaction oil was performed (hereinafter, the oil and fat after the treatment for reducing glycerin is also referred to as "deglycerinated oil"), and then, by performing a treatment of contacting an adsorbent with the deglycerinated oil for a predetermined time or longer, it was found that monoacylglycerol in the produced transesterified oil and fat was reduced and the diacylglycerol concentration increased.

[0006] That is, the present invention provides a method for producing a transesterified oil and fat, which comprises performing a treatment for reducing glycerin dissolved in the reaction oil after subjecting an oil and fat and glycerin to a transesterification reaction, and then performing a treatment of contacting an adsorbent with the deglycerinated oil for 20 minutes or longer.

Effects of the Invention

[0007] According to the present invention, it is possible to produce a transesterified oil and fat having a small amount of monoacylglycerol and a high content of diacylglycerol.

Modes for Carrying Out the Invention

[0008] The method for producing the transesterified oil and fat of the present invention comprises performing a treatment to reduce glycerin dissolved in the reaction oil after subjecting the oil and fat and glycerin to a transesterification reaction, and then performing a treatment of bringing an adsorbent into contact with the deglycerinated oil for 20 minutes or more. In this specification, "oil and fat" and "oil" are synonymous. Further, the substances constituting the oil and fat (oil) include not only triacylglycerol but also monoacylglycerol and diacylglycerol. That is, the oil and fat (oil) contains any one or more of monoacylglycerol, diacylglycerol, and triacylglycerol.

[0009] In the present invention, the oil and fat to be reacted with glycerin generally mainly consists of triacylglycerol. For example, vegetable oils and fats such as 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, egoma oil, chia seed oil, Sacha inchi oil, walnut oil, kiwi seed oil, salvia seed oil, grape seed oil, macadamia nut oil, hazelnut oil, pumpkin seed oil, camellia oil, tea seed oil, borage oil, palm oil, palm olein, palm stearin, coconut oil, palm kernel oil, cocoa butter, seal oil, shea butter, algal oil; animal fats and oils such as fish oil, sea lion oil, whale oil, lard, beef tallow, butter fat; microbial oils such as oils and fats derived from polyunsaturated fatty acid-producing microorganisms such as zygomycetes; or oils and fats such as transesterified oils and fats, hydrogenated oils, and fractionated oils thereof. The oil and fat can be used alone or in combination of two or more. Among them, the oil and fat is preferably a liquid oil and fat from the viewpoints of the emulsifying properties of the transesterified oil and fat and ease of handling. The liquid oil and fat refers to an oil and fat that is liquid at 20°C when a cooling test is performed according to the standard oil and fat analysis test method 2.3.8-27. In the present invention, from the viewpoint of expecting various physiological functions, it is preferable to use an oil or fat to which a fatty acid having a carbon chain length of 18 or more and 3 or more double bonds is bonded. In particular, it is preferable to use one or more oils or fats selected from oils or fats rich in ω3 polyunsaturated fatty acids, such as perilla oil, linseed oil, egao oil, chia seed oil, Sacha inchi oil, algal oil, fish oil, seal oil, whale oil, and oils or fats derived from polyunsaturated fatty acid-producing microorganisms.

[0010] Fish oil can be obtained, for example, from raw materials such as sardines, herrings, sauries, mackerels, bonitos, tunas, squids, and cod livers. Algal oil can be obtained from algae belonging to Chlorophyceae, Bacillariophyceae, etc. Prior to the reaction, it is preferable to appropriately perform known separation means and purification means such as liquid-liquid separation, filtration, and centrifugation in order to remove impurities. Alternatively, a so-called concentrated oil in which the ratio of unsaturated fatty acids such as eicosapentaenoic acid (C20:5, EPA) and docosahexaenoic acid (C22:6, DHA) in the fatty acids constituting the oil or fat is increased by selectively hydrolyzing fish oil or the like using lipase may be used.

[0011] The content of triacylglycerol in the oil or fat may be 100% by mass, but from the viewpoint of facilitating the concentration of eicosapentaenoic acid and docosahexaenoic acid, which are highly unsaturated fatty acids, in the interesterified oil or fat, it is preferably 95% by mass or less, more preferably 92% by mass or less, still 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, still more preferably 80% by mass or more. In order to make the content of triacylglycerol in the oil or fat to be reacted with glycerol less than 100% by mass, it is preferable to allow lipase to act on the oil or fat to cause partial hydrolysis, and then remove the resulting fatty acids by distillation. By this operation, saturated fatty acids having 16 and 18 carbon atoms in the constituent fatty acids can be selectively removed, and highly unsaturated fatty acids can be more concentrated in the oil or fat to be reacted with glycerol. Also, the content of free fatty acids or their salts in the oil or fat is preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 4% by mass or less, and even more preferably 1% by mass or less from the viewpoint of suppressing the deactivation of the catalyst. Further, from the viewpoint of production efficiency, it is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and still more preferably 0.03% by mass or more.

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

[0013] From the viewpoint of having a physiological activity function, the fatty acids constituting the oil or fat preferably contain a large amount of fatty acids having a carbon chain length of 18 or more and 3 or more double bonds. Further, according to the method of the present invention, it is possible to obtain a transesterified oil or fat having a high ratio of fatty acids having a carbon chain length of 18 or more and 3 or more double bonds in the reaction oil while suppressing the ratio of the fatty acids having a carbon chain length of 18 or more and 3 or more double bonds in the reaction oil from becoming lower than the ratio of the fatty acids having a carbon chain length of 18 or more and 3 or more double bonds in the oil or fat as the reaction raw material. The total content of fatty acids having a carbon chain length of 18 or more and 3 or more double bonds in the fatty acids constituting the oil or fat is preferably 15% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more, and even more preferably 30% by mass or more from the viewpoints of physiological activity functions and the ease of enjoying the effects of the present invention. Further, from the viewpoint 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 still more preferably 80% by mass or less. The total content of fatty acids having a carbon chain length of 18 or more and 3 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, still more preferably 25 to 80% by mass, and even more preferably 30 to 80% by mass. Examples of the fatty acids having a carbon chain length of 18 or more and 3 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), docosahexaenoic acid (C22:6, DHA), and the like. Among them, from the viewpoints of physiological activity functions and the ease of enjoying the effects of the present invention, ω3 unsaturated fatty acids having a double bond at the 3rd position counted from the methyl group terminal of the carbon chain are preferred.

[0014] The glycerin used in the present invention is preferably one having a purity of 95% by mass or more from the viewpoint of improving reactivity.

[0015] In the present invention, the ratio [FA / GLY] of the number of moles of fatty acid groups to the number of moles of glycerol groups when reacting the oil or fat with glycerin is preferably 2.0 or less, more preferably 1.7 or less, still more preferably 1.4 or less from the viewpoint of diacylglycerol production. Further, from the viewpoint of reducing glycerin that does not dissolve in the oil phase, it is preferably 0.60 or more, more preferably 0.65 or more, and still more preferably 0.70 or more. The ratio [FA / GLY] of the number of moles of fatty acid groups to the number of moles of glycerol groups when reacting the oil or fat with glycerin is preferably 0.60 to 2.0, more preferably 0.65 to 1.7, and still 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 represented by the following formula (1). FA / GLY = (the number of moles of fatty acid + the number of moles of monoacylglycerol + the number of moles of diacylglycerol × 2 + the number of moles of triacylglycerol × 3) / (the number of moles of glycerin + the number of moles of monoacylglycerol + the number of moles of diacylglycerol + the number of moles of triacylglycerol) (1)

[0016] In the present invention, for the transesterification reaction between oil and fat and glycerin, a conventionally known method may be adopted, and either a chemical method or an enzymatic method is possible. However, it is preferable to carry out the reaction by a chemical method using a chemical catalyst from the viewpoint of promoting the transesterification reaction. The chemical catalyst used in the present invention may be any one that catalyzes the reaction. For example, alkali metal hydroxides, alkaline earth metal hydroxides, and alkoxides having 1 to 3 carbon atoms can be mentioned. 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, and examples of alkoxides having 1 to 3 carbon atoms include sodium methoxide and sodium ethoxide. Among them, calcium hydroxide and sodium methoxide are preferable.

[0017] From the viewpoint of improving reactivity, the addition amount of the chemical catalyst is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and still more preferably 0.03% by mass or more with respect to the reaction raw materials (the total of oil and fat and glycerin). Also, from the viewpoint of reducing the amount of the neutralizing agent, it is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 1.5% by mass or less. From the same viewpoint, when the chemical catalyst is calcium hydroxide or sodium methoxide, the addition amount is preferably 0.04 to 1.5% by mass with respect to the reaction raw materials. 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 oil and fat and glycerin is carried out.

[0018] In the present invention, from the viewpoint of improving the reaction rate, the reaction temperature is preferably 90°C or higher, more preferably 95°C or higher, still more preferably 100°C or higher. 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, still more preferably 220°C or lower. The reaction temperature is preferably 90 to 250°C, more preferably 95 to 235°C, still more preferably 100 to 220°C. Further, when using an oil or fat in which a fatty acid having a carbon chain length of 18 or more and 3 or more double bonds is bonded as a raw material, from the viewpoint of suppressing the formation of trans fatty acids, it is preferable that the upper limit of the temperature during the transesterification reaction is 165°C or lower, more preferably 160°C or lower, still more preferably 155°C or lower. When using an oil or fat in which a fatty acid having a carbon chain length of 18 or more and 3 or more double bonds is bonded as a raw material, the reaction temperature is preferably 90 to 165°C, more preferably 95 to 160°C, still more preferably 100 to 155°C.

[0019] From the viewpoints of suppressing the deactivation of the catalyst and industrial productivity, the heating rate of the reaction raw material to the reaction temperature is preferably 0.1°C / min or higher, more preferably 0.15°C / min or higher, still more preferably 0.2°C / min or higher. Also, from the viewpoint of reducing the heating load on the equipment, it is preferably 20°C / min or lower, more preferably 10°C / min or lower, still more preferably 3°C / min or lower. The heating rate of the reaction raw material to the reaction temperature is preferably 0.1 to 20°C / min, more preferably 0.15 to 10°C / min, still more preferably 0.2 to 3°C / min.

[0020] From the viewpoint of diacylglycerol production, the reaction time is preferably 0.2 hours or longer, more preferably 0.4 hours or longer, still more preferably 0.6 hours or longer. Also, from the viewpoint of industrial productivity, it is preferably within 15 hours, more preferably within 12 hours, still more preferably within 9 hours. The reaction time is preferably 0.2 hours or longer and within 15 hours, more preferably 0.4 hours or longer and within 12 hours, still more preferably 0.6 hours or longer and within 9 hours.

[0021] The reaction between the oil and fat and glycerin is preferably carried out after removing the water contained in the reaction raw materials by means of reduced pressure, nitrogen bubbling, etc., from the viewpoints of improving the reactivity and suppressing the decline in catalyst performance. From the viewpoints of industrial productivity and suppressing the decline in catalyst performance, the water concentration of the reaction raw materials before adding the catalyst is preferably 0.01 to 0.5% by mass, more preferably 0.03 to 0.4% by mass, and still more preferably 0.05 to 0.3% by mass.

[0022] The reaction may be carried out under reduced pressure or normal pressure usually. The pressure when carried out under reduced pressure is not particularly limited, but from the viewpoint of reducing the moisture in the reaction system, it is preferably 13,000 Pa or less. When carried out under normal pressure, in order to suppress the oxidation of the transesterified oil and fat obtained, it is preferably carried out under a nitrogen atmosphere in which nitrogen is circulated.

[0023] After the transesterification reaction is completed, the chemical catalyst used as the 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 from the viewpoints that the neutralized product is insoluble in water and oil and fat and can be easily removed by filtration, acids such as sulfuric acid, hydrochloric acid, and phosphoric acid are preferable, and phosphoric acid is more preferable.

[0024] In the present invention, the neutralization of the chemical catalyst is preferably carried out by adding a neutralizing agent to the chemical catalyst in an amount of preferably 1.2 molar times or more, more preferably 1.25 molar times or more, and still more preferably 1.3 molar times or more, from the viewpoint of eliminating the catalyst activity. The upper limit of the molar ratio is not particularly limited, but from the viewpoint of suppressing the increase in the acid value of the neutralized oil, it is preferably 3.0 molar times or less, more preferably 2.6 molar times or less, and still more preferably 2.2 molar times or less. The amount of the neutralizing agent with respect to the chemical catalyst is preferably 1.2 to 3.0 molar times, more preferably 1.25 to 2.6 molar times, and still more preferably 1.3 to 2.2 molar times.

[0025] In the neutralization process, that is, in the process of adding a neutralizing agent to the reaction oil containing a chemical catalyst and ending stirring (the same applies hereinafter), the temperature 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 generating the neutralized product. Further, from the viewpoint of suppressing the reverse reaction and suppressing oxidation, it is preferably 250 °C or lower, more preferably 235 °C or lower, and even more preferably 220 °C or lower.

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

[0027] In the neutralization process, from the viewpoint of sufficiently generating the neutralized product, it is preferable to perform neutralization while stirring. The means for stirring is not particularly limited.

[0028] After the neutralization process, it is preferable to separate glycerin that forms a heterogeneous phase with the reaction oil. When the ratio [FA / GLY] of the number of moles of fatty acid groups to the number of moles of glycerin groups is lowered, glycerin that does not dissolve in the oil phase and the neutralization product are present in the reaction oil after the neutralization process. Therefore, a step of separating these after neutralization is performed. Examples of the separation means include methods by filtration, sedimentation separation, and centrifugation that can be easily performed. Among them, from the viewpoint of being able to separate the catalyst and unreacted glycerin simultaneously, the method by centrifugation is preferable.

[0029] The glyceride composition of the reaction oil after separating glycerin that does not dissolve in the oil phase and the neutralization product is such that, from the viewpoint of improving the physiological activity function, the content of diacylglycerol is preferably 15 to 60% by mass, more preferably 20 to 55% by mass, and even more preferably 25 to 55% by mass; the content of monoacylglycerol is preferably 15 to 60% by mass, more preferably 20 to 55% by mass, and even more preferably 25 to 50% by mass; the content of triacylglycerol is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 5 to 15% by mass; and the content of free fatty acid is 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.

[0030] The reaction oil after the transesterification reaction contains glycerin dissolved therein. Therefore, in the present invention, a treatment for reducing the glycerin dissolved in the reaction oil is then performed. The glycerin concentration in the reaction oil before performing the treatment for reducing glycerin is preferably 1.5% by mass or more, more preferably 1.8% by mass or more, still more preferably 2.0% by mass or more, and even more preferably 2.5% by mass or more from the necessity of reducing the glycerin concentration. The upper limit is preferably 9% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less from the point of the dissolution limit of glycerin in fats and oils. The glycerin concentration in the reaction oil before performing the treatment for reducing glycerin is preferably 1.5 to 9% by mass, more preferably 1.8 to 7% by mass, still 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 glycerin dissolved in the reaction oil include, but are not limited to, distillation treatment, water washing treatment, deodorization treatment, etc. The treatment for reducing glycerin dissolved in the reaction oil can be performed by combining one or more treatments.

[0032] Examples of the vacuum device used for the distillation treatment include a batch simple distillation device, a batch rectification device, a continuous rectification device, a flash evaporation device, a thin-film evaporation device, etc. Among them, the thin-film evaporation device is preferable from the points of reducing equipment costs and operating costs, increasing the distillation capacity, and being able to optimally select the distillation temperature. In the distillation treatment, the distillation conditions for making the glycerin concentration of the de-glycerinated oil after distillation within the concentration range described later can be set based on the vapor pressure curve. The distillation temperature is preferably 200°C or lower, more preferably 175°C or lower, still more preferably 150°C or lower, from the viewpoints that monoacylglycerol, diacylglycerol and triacylglycerol are not distilled off and that no heat history is imparted. Also, from the viewpoint of the distillation efficiency of glycerin, it is preferably 20°C or higher, more preferably 40°C or higher, still more preferably 60°C or higher. The distillation temperature is preferably 20 to 200°C, more preferably 40 to 175°C, still more preferably 60 to 150°C. The degree of vacuum in the distillation treatment is preferably 5000 Pa or lower, more preferably 500 Pa or lower, still more preferably 50 Pa or lower, from the viewpoints that monoacylglycerol, diacylglycerol and triacylglycerol are not distilled off and that no heat history is imparted. Also, from the viewpoint of the distillation efficiency of glycerin, it is preferably 0.01 Pa or higher, more preferably 0.1 Pa or higher, still more preferably 1 Pa or higher. The degree of vacuum is preferably 0.01 to 5000 Pa, more preferably 0.1 to 500 Pa, still more preferably 1 to 50 Pa.

[0033] The water washing treatment may be repeated a plurality of times, for example, 2 or 3 times. Examples of the method of bringing water into contact with the reaction oil include a batch method in which the reaction oil and water are mixed and stirred and then filtered. Prior to bringing water into contact with the reaction oil, an aqueous solution containing a chelating agent such as citric acid may be added to and mixed with the reaction oil. At this time, it is preferable to conduct the operation under a stream of an inert gas such as nitrogen. Examples of the 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, still more preferably 5 to 200% by mass, based on the reaction oil, from the viewpoint that glycerin can be sufficiently removed. The temperature of the water washing treatment is preferably 90°C or lower, more preferably 20 to 90°C, still more preferably 30 to 80°C, from the viewpoints of industrial productivity and sufficient contact between the reaction oil and water. Also, from the same viewpoints, the time of the water washing treatment is preferably 0.1 to 120 minutes, more preferably 0.2 to 60 minutes, still more preferably 0.3 to 30 minutes.

[0034] The deodorization treatment is basically carried out by vacuum steam distillation, and examples include batch type, semi-continuous type, continuous type, etc. The deodorization treatment of bringing steam into contact under reduced pressure can be carried out by using a thin-film deodorizer or a tray-type deodorizer alone, or by combining the deodorization treatment using these thin-film deodorizers and the treatment using a tray-type deodorizer. In the present invention, from the viewpoints of equipment cost, flavor, etc., a method of carrying out the treatment using a thin-film column or a tray-type deodorizer alone is preferable. The deodorization temperature is preferably 250°C or lower, more preferably 230°C or lower, still more preferably 210°C or lower, from the viewpoints that monoacylglycerol, diacylglycerol, and triacylglycerol are not distilled off and that no heat history is given. Also, from the viewpoint of the distillation efficiency of glycerin, it is preferably 50°C or higher, more preferably 80°C or higher, still more preferably 100°C or higher. The deodorization temperature is preferably 50 to 250°C, more preferably 80 to 230°C, still more preferably 100 to 210°C. The degree of vacuum in the deodorization treatment is preferably 20,000 Pa or lower, more preferably 10,000 Pa or lower, still more preferably 5,000 Pa or lower, from the viewpoints that diacylglycerol and triacylglycerol are not distilled off and that no heat history is given. Also, from the viewpoint of the distillation efficiency of glycerin, it is preferably 10 Pa or higher, more preferably 50 Pa or higher, still more preferably 100 Pa or higher. The degree of vacuum is preferably 10 to 20,000 Pa, more preferably 50 to 10,000 Pa, still more preferably 100 to 5,000 Pa. The amount of steam is preferably 0.5 to 20% / h, more preferably 1.0 to 10% / h, from the viewpoint of the distillation efficiency of glycerin.

[0035] The glycerin concentration in the deglycerinated oil after the treatment for reducing glycerin is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, still more preferably 2.0% by mass or less, even more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less from the viewpoint of being able to generate a large amount of diacylglycerol. Also, the glycerin concentration in the deglycerinated 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 still more preferably 0.1% by mass or more. The glycerin concentration in the deglycerinated oil after the treatment for reducing glycerin is preferably 3.0% by mass or less, more preferably 0.001 to 3.0% by mass, still more preferably 0.001 to 2.5% by mass, even more preferably 0.01 to 2.0% by mass, even more preferably 0.01 to 1.5% by mass, and even more preferably 0.1 to 1.0% by mass.

[0036] Also, from the viewpoint of improving the bioactive function, the glyceride composition of the deglycerinated oil after the treatment for reducing glycerin is such that the content of diacylglycerol is preferably 15 to 61% by mass, more preferably 20 to 56% by mass, still more preferably 25 to 56% by mass, the content of triacylglycerol is preferably 31% by mass or less, more preferably 21% by mass or less, still more preferably 5 to 16% by mass, the content of monoacylglycerol is preferably 15 to 61% by mass, more preferably 20 to 56% by mass, still more preferably 25 to 51% by mass, and the content of free fatty acid is preferably 10% by mass or less, more preferably 0.1 to 7% by mass, and still more preferably 0.1 to 5% by mass.

[0037] Next, the treatment of bringing the adsorbent into contact with the deglycerinated oil is carried out for 20 minutes or more. As the adsorbent, a porous adsorbent is preferred, and examples thereof include activated carbon, silicon dioxide, and solid acid adsorbents. Examples of the solid acid adsorbent include acid clay, activated clay, activated alumina, silica gel, silica-alumina, and aluminum silicate. These can be used alone or in combination of two or more. Among them, the solid acid adsorbent is preferred, and acid clay and activated clay are particularly preferred, from the viewpoints of reducing the content of by-products and having good flavor and hue.

[0038] Acid clay and activated clay both contain, as common chemical components, SiO2, Al2O3, Fe2O3, CaO, MgO, etc. It is preferable that the SiO2 / Al2O3 ratio is 3 to 12, particularly 4 to 10. Also, those having a composition containing 1 to 5% of Fe2O3, 0 to 1.5% of CaO, and 1 to 7% of MgO are preferable.

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

[0040] In this treatment, from the viewpoint of fast filtration speed and good productivity, perlite, silicon dioxide, diatomaceous earth, etc. may be appropriately added as a filter aid.

[0041] The amount of adsorbent used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, based on the deglycerolized oil, from the viewpoint of being able to produce a large amount of diacylglycerol. Also, from the viewpoint of industrial productivity, it is preferably 10% by mass or less, more preferably 6% by mass or less, still more preferably 3% by mass or less. The amount of adsorbent used is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, still more preferably 0.5 to 3% by mass.

[0042] The contact temperature between the deglycerolized oil and the adsorbent is preferably 20°C or higher, more preferably 40°C or higher, still more preferably 60°C or higher, from the viewpoint of being able to produce a large amount of diacylglycerol. Also, from the viewpoints of oxidation suppression and industrial productivity, it is preferably 150°C or lower, more preferably 135°C or lower, still more preferably 120°C or lower.

[0043] The contact time is 20 minutes or longer. From the viewpoint of being able to produce a large amount of diacylglycerol, it is preferably 30 minutes or longer, more preferably 45 minutes or longer, still more preferably 60 minutes or longer. Also, from the viewpoints of oxidation suppression and industrial productivity, it is preferably within 10 hours, more preferably within 5 hours, still more preferably within 3 hours. The contact time is 20 minutes or longer, preferably 20 minutes to 10 hours, more preferably 30 minutes to 10 hours, still more preferably 45 minutes to 5 hours, even more preferably 60 minutes to 3 hours.

[0044] The pressure may be under reduced pressure or at normal pressure, but from the viewpoint of suppressing the oxidation of fats and oils, reduced pressure is preferred. In the case of normal pressure, a nitrogen atmosphere is preferred. The specific pressure is preferably 100 to 13000 Pa, more preferably 500 to 10000 Pa, still more preferably 1000 to 5000 Pa.

[0045] After performing the treatment of bringing the adsorbent into contact with the deglycerolized oil, an operation of separating the adsorbent is carried out. Filtration is preferably used as the separation means, and as the filtration means, any of suction filtration, pressure filtration, centrifugal filtration, etc. can be implemented, and a filter used in the decolorization step of fats and oils can be used.

[0046] Regarding the glyceride composition of the adsorbent-treated oil of the present invention, from the viewpoint of improving the physiological activity function, the content of diacylglycerol is preferably 18 to 72% by mass, more preferably 23 to 67% by mass, still more preferably 28 to 67% by mass, the content of triacylglycerol is preferably 31% by mass or less, more preferably 21% by mass or less, still more preferably 5 to 16% by mass, and the content of monoacylglycerol is preferably 12 to 58% by mass, more preferably 17 to 53% by mass, still more preferably 22 to 48% by mass.

[0047] As a result of the treatment of the present invention, monoacylglycerol in the adsorbent-treated oil is reduced and the concentration of diacylglycerol increases. Therefore, it is possible to obtain a transesterified oil and fat having a low content of monoacylglycerol and a high content of diacylglycerol. In the transesterified oil and fat, from the viewpoint of enhancing the physiological effect, the increase amount of diacylglycerol after the treatment of bringing the de-glycerolized oil into contact with the adsorbent is preferably 3.5% by mass or more, more preferably 4.0% by mass or more, still more preferably 5.0% by mass or more, and even more preferably 6.0% by mass or more, from before the treatment of bringing the de-glycerolized oil into contact with the adsorbent. Also, from the viewpoint of industrial productivity, it is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. In the transesterified oil and fat, the increase amount of diacylglycerol after the treatment of bringing the de-glycerolized oil into contact with the adsorbent is preferably 3.5 to 20% by mass, more preferably 4.0 to 15% by mass, still more preferably 5.0 to 10% by mass, and even more preferably 6.0 to 10% by mass, from before the treatment of bringing the de-glycerolized oil into contact with the adsorbent.

[0048] The transesterified oil and fat obtained by the method of the present invention is rich in diacylglycerol, and its glyceride composition is the same as that of the above-mentioned adsorbent-treated oil. Further, if necessary, concentration of diacylglycerol or a refining step for ordinary oils and fats other than the above treatment may be performed, and it can be used in the same manner as general edible oils and fats.

[0049] Regarding the above-described embodiments, the present invention further discloses the following method for producing a transesterified oil and fat. <1> A method for producing a transesterified oil and fat, which comprises performing a treatment for reducing glycerol dissolved in the reaction oil after subjecting an oil and fat and glycerol to a transesterification reaction, and then performing a treatment of bringing an adsorbent into contact with the de-glycerolized oil for 20 minutes or more. <2> The method for producing transesterified oil and fat according to <1>, wherein the glycerin concentration in the de-glycerinated 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 <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 <1> to <3>, wherein the contact temperature between the de-glycerinated oil and the adsorbent is 20 °C or higher. <5> The method for producing transesterified oil and fat 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 transesterified oil and fat according to any one of <1> to <5>, wherein the adsorbent is one or more selected from acidic clay and activated clay. <7> The method for producing transesterified oil and fat according to any one of <1> to <6>, wherein the adsorbent is brought into contact with the de-glycerinated oil in an amount of 10% by mass or less. <8> The method for producing transesterified oil and fat according to any one of <1> to <7>, wherein the glycerin concentration in the reaction oil before the treatment for reducing glycerin is 1.5 to 9% by mass. <9> The method for producing transesterified oil and fat according to any one of <1> to <8>, wherein in the transesterified oil and fat, the increase amount of diacylglycerol after the treatment of bringing the adsorbent into contact with the de-glycerinated oil is 3.5 to 20% by mass from before the treatment of bringing the adsorbent into contact with the de-glycerinated oil. <10> The method for producing transesterified oil and fat according to any one of <1> to <9>, wherein the diacylglycerol content in the adsorbent-treated oil is 18 to 72% by mass. <11> The method for producing transesterified oil and fat according to any one of <1> to <10>, wherein the monoacylglycerol content in the adsorbent-treated oil is 12 to 58% by mass. <12> In the method for producing transesterified oil and fat according to any one of <1> to <11>, the total content of fatty acids having a carbon chain length of 18 or more and 3 or more double bonds among the fatty acids constituting the oil and fat is 15 to 99% by mass. <13> In the method for producing transesterified oil and fat according to any one of <1> to <12>, the glycerin concentration in the reaction oil before the treatment for reducing glycerin is 1.8 to 7% by mass, and the glycerin concentration in the deglycerinated oil is 0.001 to 2.5% by mass. <14> In the method for producing transesterified oil and fat according to any one of <1> to <13>, an adsorbent is brought into contact with the deglycerinated oil having a glycerin concentration of 2.0% by mass or less in an amount of 0.1 to 10% by mass. <15> In the transesterified oil and fat, the increase amount of diacylglycerol after the treatment of bringing the adsorbent into contact with the deglycerinated oil is 4.0 to 15% by mass, and the diacylglycerol content in the transesterified oil and fat is 23 to 67% by mass, from before the treatment of bringing the adsorbent into contact with the deglycerinated oil to after the treatment, in the method for producing transesterified oil and fat according to any one of <1> to <14>. <16> In the method for producing transesterified oil and fat according to any one of <1> to <15>, the ratio [FA / GLY] of the number of moles of fatty acid groups to the number of moles of glycerol groups when reacting the oil and fat with glycerol is 0.60 to 2.0.

Examples

[0050] In the following examples, “%” means “% by mass”.

[0051] 〔Analysis method〕 (i) Measurement of glyceride composition About 10 mg of the oil and fat and 0.5 mL of a trimethylsilylating agent (“Silylating agent TH”, manufactured by Kanto Chemical Co., Inc.) were added to 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 thereto, and the mixture was shaken. After standing, the upper layer was subjected to gas chromatography (GC) for analysis of the glyceride composition.

[0052] [Preparation of reaction oil a] The oil and fat and glycerin, which are reaction raw materials shown in Table 1, were placed in a 5 L four-necked flask equipped with a stirring blade (90 mm × 25 mm). While stirring at 400 r / min, dehydration under reduced pressure was carried out at 80°C and 400 Pa for 30 minutes. Then, while introducing nitrogen, the pressure was returned to normal pressure, and while nitrogen was circulated in the space part in the flask, the temperature was raised to the reaction temperature of 150°C at a rate of 1°C / min. Next, calcium hydroxide was added as a catalyst at 0.10% by mass based on the raw materials, and a transesterification reaction was carried out under the conditions of a temperature of 150°C and normal pressure (nitrogen circulation). 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, and the mixture was stirred for 30 minutes for neutralization. Then, it was cooled to 60°C and centrifuged at 3000 r / min for 10 minutes to remove the precipitated glycerin and catalyst to obtain reaction oil a. The analysis results of reaction oil a are shown in Table 1.

[0053] [Preparation of reaction oil b] The oil and fat and glycerin, which are reaction raw materials shown in Table 1, were placed in a 1 L four-necked flask equipped with a stirring blade (90 mm × 25 mm). Except for adding the catalyst after reaching the reaction temperature of 210°C and setting the reaction time to 1 hour, the same treatment as that for reaction oil a was carried out to obtain reaction oil b. The analysis results of reaction oil b are shown in Table 1.

[0054] [Preparation of reaction oil c] The oil and fat and glycerin, which are reaction raw materials shown in Table 1, were placed in a 2 L four-necked flask equipped with a stirring blade (90 mm × 25 mm). Except for using sodium methoxide as the catalyst and adding it at 0.22% by mass based on the raw materials, the same treatment as that for reaction oil a was carried out to obtain reaction oil c. The analysis results of reaction oil c are shown in Table 1.

[0055] [Preparation of reaction oil d] Except for using calcium hydroxide as the catalyst and setting it at 0.05% by mass based on the raw materials, the same treatment as that for reaction oil c was carried out to obtain reaction oil d. The analysis results of reaction oil d are shown in Table 1.

[0056] [Preparation of reaction oil e] The oil and fat and glycerin, which are reaction raw materials shown in Table 1, were placed in a 2L four-necked flask equipped with a stirring blade (90 mm × 25 mm). The same treatment as that for reaction oil a was carried out except that the catalyst was 0.15% by mass based on the raw materials, and reaction oil e was obtained. The analysis results of reaction oil e are shown in Table 1.

[0057] [Table 1]

[0058] [Example 1] Using a wiped film evaporator (Shinko Environmental Solutions Co., Ltd. Model 2-03, inner diameter 5 cm, heat transfer area 0.03 m2), reaction oil a was subjected to thin film distillation. It was operated under the conditions of a heating 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 the thin film distilled oil a was placed in a 300 mL four-necked flask equipped with a stirring blade (60 mm × 20 mm). While stirring at 400 r / min, it was dehydrated under reduced pressure at 80 °C and 400 Pa for 30 minutes. Then, the temperature was raised to 110 °C, and 1.5 g of activated clay (Galeon Earth V2R: manufactured by Mizusawa Chemical Industry Co., Ltd.) was added, and it was treated with the adsorbent at normal pressure for 120 minutes. Sampling was carried out after 10, 20, 30, 60, 90, and 120 minutes, cooled to 70 °C, and the activated clay was filtered off to obtain adsorbent-treated oils a, b, c, d, e, and f. The compositions of the thin film distilled oil a and the adsorbent-treated oil f are shown in Table 2, and the compositions of the adsorbent-treated oils a to f are shown in Table 3.

[0059] [Example 2] The activated clay treatment was carried out in the same manner as in Example 1 except that the addition amount of the activated clay was 4.5 g and the sampling time was 120 minutes to obtain an adsorbent-treated oil. The results are shown in Table 2.

[0060] [Example 3] The activated clay treatment was carried out in the same manner as in Example 1 except that the temperature of the adsorbent treatment was 80 °C and the sampling time was 120 minutes to obtain an adsorbent-treated oil. The results are shown in Table 2.

[0061] [Comparative Example 1] An activated clay treatment similar to that of Example 1 was performed except that no activated clay was added and the sampling time was 120 minutes, and a treated oil was obtained. The results are shown in Table 2.

[0062] [Example 4] To a 1 L four-necked flask equipped with a stirring blade (90 mm × 25 mm), 50% aqueous citric acid solution was added to reaction oil a at 0.5% by mass based on reaction oil a, and the mixture was stirred at 300 r / min at 70°C for 30 minutes under a nitrogen atmosphere. Then, distilled water was added to reaction oil a at 100% by mass, and the mixture was stirred at 300 r / min at 70°C for 10 minutes under a nitrogen atmosphere, followed by centrifugation at 3000 r / min for 10 minutes to remove the precipitated aqueous phase. This water washing operation was repeated three times, and dehydration was carried out at 70°C for 30 minutes at 300 r / min under a pressure of 400 Pa or less, and then returned to normal pressure with nitrogen to obtain washed oil a. Using washed oil a, an activated clay treatment was carried out in the same manner as in Example 1 except that the sampling time was 120 minutes to obtain an adsorbent-treated oil. The compositions of washed oil a and the adsorbent-treated oil are shown in Table 2.

[0063] [Comparative Example 2] An 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 2.

[0064] [Example 5] Reaction oil b was subjected to thin-film distillation under the same conditions as in Example 1 to obtain thin-film distilled oil b. Then, an activated clay treatment similar to that of Example 1 was performed, and sampling was carried out after 120 minutes to obtain an adsorbent-treated oil. The compositions of thin-film distilled oil b and the adsorbent-treated oil are shown in Table 2.

[0065] [Example 6] Reaction oil c was subjected to thin-film distillation under the same conditions as in Example 1 to obtain thin-film distilled oil c. Then, thin-film distilled oil c was subjected to an activated clay treatment similar to that of Example 1, and sampling was carried out after 120 minutes to obtain an adsorbent-treated oil. The compositions of thin-film distilled oil c and the adsorbent-treated oil are shown in Table 2.

[0066] [Comparative Example 3] Activated clay treatment was carried out in the same manner as in Example 1, except that the raw material oil to be treated was used as reaction oil c and the sampling time was 120 minutes, to obtain an adsorbent-treated oil. The results are shown in Table 2.

[0067] [Example 7] Reaction oil d was subjected to thin-film distillation under the same conditions as in Example 1 to obtain thin-film distilled oil d. The glycerin concentration of the thin-film distilled oil d was 0.3%. Next, glycerin (manufactured by Kao Corporation) was added to and mixed with the thin-film distilled oil d to adjust the glycerin concentration to 0.6% to obtain glycerin concentration-adjusted oil a. Then, the same activated clay treatment as in Example 1 was carried out, and sampling was performed after 120 minutes to obtain an adsorbent-treated oil. The compositions of the glycerin concentration-adjusted oil a and the adsorbent-treated oil are shown in Table 2.

[0068] [Example 8] Glycerin (manufactured by Kao Corporation) was added to and mixed with the thin-film distilled oil d to adjust the glycerin concentration to 1.0% to obtain glycerin concentration-adjusted oil b. Then, the same activated clay treatment as in Example 1 was carried out, and sampling was performed after 120 minutes to obtain an adsorbent-treated oil. The compositions of the glycerin concentration-adjusted oil b and the adsorbent-treated oil are shown in Table 2.

[0069] [Example 9] Glycerin (manufactured by Kao Corporation) was added to and mixed with the thin-film distilled oil d to adjust the glycerin concentration to 1.6% to obtain glycerin concentration-adjusted oil c. Then, the same activated clay treatment as in Example 1 was carried out, and sampling was performed after 120 minutes to obtain an adsorbent-treated oil. The compositions of the glycerin concentration-adjusted oil c and the adsorbent-treated oil are shown in Table 2.

[0070] [Example 10] 200 g of reaction oil a was placed in a Claisen flask and deodorized at a temperature of 130°C, a pressure of 400 Pa, and a steam amount of 3% / h for 1 hour to obtain deodorized oil a. Then, the same activated clay treatment as in Example 1 was carried out, and sampling was performed after 120 minutes to obtain an adsorbent-treated oil. The compositions of the deodorized oil a and the adsorbent-treated oil are shown in Table 2.

[0071] [Example 11] 200 g of reaction oil a was put into a Claisen flask and deodorized for 1 hour under the conditions of a temperature of 200 °C, a pressure of 400 Pa, and a steam amount of 3% / h to obtain deodorized oil b. Subsequently, the same activated clay treatment as in Example 1 was carried out, and sampling was performed after 120 minutes to obtain adsorbent-treated oil. The compositions of deodorized oil b and the adsorbent-treated oil are shown in Table 2.

[0072] [Example 12] Reaction oil e was subjected to thin-film distillation under the same conditions as in Example 1 to obtain thin-film distilled oil d. Subsequently, thin-film distilled oil d was subjected to the same activated clay treatment as in Example 1, and sampling was performed 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 2.

[0073] [Comparative Example 4] 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 e and the sampling time was 120 minutes to obtain adsorbent-treated oil. The results are shown in Table 2.

[0074] [Table 2]

[0075] [Table 3]

[0076] As is clear from Tables 2 and 3, regardless of the concentration of glycerin dissolved in the reaction oil due to different reaction conditions, when the reaction oil after the transesterification reaction is subjected to adsorption treatment after reducing the glycerin concentration by distillation, washing with water, or deodorization, it was found that the triacylglycerol in the adsorption-treated oil remained unchanged, the monoacylglycerol decreased, and the diacylglycerol increased efficiently (Examples 1 to 12). On the other hand, it was found that there was no change in the glyceride composition when the reaction oil was directly subjected to adsorption treatment or when deglycerolization was performed without adding activated clay (Comparative Examples 1 to 4). Further, as a result of adding glycerin to the thin-film distilled oil obtained by distilling the reaction oil and adjusting the glycerin concentration to perform adsorption treatment, it was found that the lower the glycerin concentration of the oil and fat before the adsorption treatment, the larger the increase amount of diacylglycerol in the adsorption treatment (Examples 7 to 9).

Claims

**Claim 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 for 20 minutes or more. **Claim 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. **Claim 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 of oil and fat and glycerin is 2.0 or less. **Claim 4** The method for producing transesterified oil and fat according to any one of claims 1 to 3, wherein the contact temperature between the deglycerinated oil and the adsorbent is 20°C or higher. **Claim 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 solid acid adsorbents. **Claim 6** The method for producing transesterified oil and fat according to any one of claims 1 to 5, wherein the adsorbent is one or more selected from acidic clay and activated clay. **Claim 7** The method for producing transesterified oil and fat according to any one of claims 1 to 6, wherein the adsorbent is brought into contact with the deglycerinated oil in an amount of 10% by mass or less.

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