Method for producing refined oil and fat

Abstract

The present invention is to provide a method for producing a refined oil and fat, which enables efficient obtainment of an oil and fat in which the concentration of one or more of 3-MCPDs and glycidols is sufficiently reduced. The production method includes a bleaching process in which a temperature of oil and fat is maintained at 100oC or higher and 170oC or lower under reduced pressure for 10 minutes or longer and 90 minutes or shorter.

Description

Refined oil and fat manufacturing method

[0001] The present invention relates to a method for producing refined oils and fats.

[0002] Regardless of the origin of the oil or fat, the production process of edible oils and fats is usually carried out in the following order: a degumming process to remove phospholipids, a deacidification process to remove free fatty acids, a bleaching process to remove pigments, and a deodorization process to remove odorous components. By going through these production processes, edible oils and fats with few impurities, a low acid value, reduced coloring, and reduced odor can be obtained.

[0003] When producing edible oils and fats such as salad oils, which require that no oil crystals form even at low temperatures, or when using oils and fats with a high wax content as raw material oils and fats, a dewaxing process may be added to the production process of edible oils and fats.

[0004] Recently, oils and fats refined by physical refining have been sold. Physical refining involves degumming and bleaching crude oil, followed by deodorization, thereby deacidifying the oils and fats without using an alkali treatment. In particular, many imported edible oils and fats have been refined by physical refining, and palm oil that has been physically refined is known among those skilled in the art as RBD (Refined Bleached Deodorized) palm oil (RBD oils and fats).

[0005] Although physically refined RBD oils are inexpensive, they are not sufficiently refined. Therefore, in most cases, physical refining is the primary refining step, and the oils refined by physical refining are then further refined by conventional secondary methods in Japan.

[0006] In recent years, with advances in analytical technology, it has become clear that not only RBD oils and fats, but also oils and fats obtained by subjecting RBD oils and fats to the above-mentioned secondary purification, and oils and fats obtained through the above-mentioned conventional production processes, contain 3-chloropropane-1,2-diol or its fatty acid esters (hereinafter, these may be collectively abbreviated as "3-MCPDs").

[0007] 3-MCPDs are thought to be unintentionally produced from components originally contained in fats and oils, particularly during the deodorization process of fats and oils, and are produced from lipids and chloride ions in the fats and oils. When fatty acid esters of 3-chloropropane-1,2-diol are ingested through food, the fatty acid esters are hydrolyzed in the body to produce 3-chloropropane-1,2-diol, and there are concerns about the adverse health effects (nephrotoxicity) of 3-chloropropane-1,2-diol. Therefore, various studies are being conducted to reduce the content of 3-MCPDs in fats and oils.

[0008] For example, studies have been conducted on deodorization at temperatures lower than the previously known deodorization temperature conditions (see Non-Patent Document 1). For example, Patent Document 1 proposes a method for reducing the amount of 3-MCPDs in fats and oils by deodorizing the fats and oils containing 3-MCPDs and the like at a low temperature of 100 to 240°C.

[0009] Another method that has been studied is to add an adsorbent to oils and fats that have become 3-MCPDs due to exposure to high temperatures during the production of refined oils and fats, particularly in the deodorization step. For example, Patent Document 2 proposes a method for reducing MCPDs in oils and fats by contacting the oils and fats that have been subjected to the decolorization step and the deodorization step with silica gel and / or basic activated carbon.

[0010] Patent Document 3 proposes a method for producing fats and oils with reduced MCPDs, which involves contacting fats and oils with one or more inorganic powders selected from the group consisting of boehmite and hydrotalcite under certain temperature conditions. Furthermore, Patent Document 4 proposes a method for reducing chloropropanediols or their fatty acid esters by performing an adsorbent treatment in which fats and oils are contacted with zeolite.

[0011] JP 2011-074358 A International Publication No. 2011 / 040539 JP 2015-067692 A JP 2020-105477 A

[0012] Japan Oil Chemists' Society, ed., Fundamentals and Applications of Fats, Oils and Lipids, 1st Edition, April 1, 2005, pp. 218-219

[0013] The methods that have been studied so far for reducing the contents of 3-MCPDs and glycidols have had the following problems.

[0014] For example, the method of adjusting the deodorization temperature as described in Patent Document 1 can deodorize fats and oils while suppressing the production of 3-MCPDs, but requires a longer deodorization treatment than conventionally known deodorization temperature conditions, resulting in poor production efficiency. Furthermore, Patent Document 1 adds up the amounts of 3-MCPDs, glycidols, etc., and calculates the total amount in terms of free 3-MCPD, so it does not disclose the specific extent to which the 3-MCPDs and glycidols have been reduced.

[0015] Furthermore, in the methods of treatment using an adsorbent, the methods described in Patent Documents 2 and 3 have the problem that the content of 3-MCPDs in fats and oils may not be sufficiently reduced. In particular, the method described in Patent Document 3 has the problem that it cannot be used to produce edible fats and oils because it uses an adsorbent that cannot be used in food production. The method described in Patent Document 4 can sufficiently reduce 3-MCPDs in fats and oils, but has the problem that the process is likely to become complicated because it requires an additional step of treatment with an adsorbent compared to conventional fat and oil production processes.

[0016] Therefore, an object of the present invention is to provide a method for producing refined fats and oils, which can efficiently produce fats and oils in which the content of at least one of 3-MCPDs and glycidols is sufficiently reduced.

[0017] In view of the above problems, the present inventors have conducted extensive research and have found that, although placing oils and fats under high temperatures at each stage of the production process of refined oils and fats has been avoided because it increases the content of 3-MCPDs, it is possible to significantly reduce the content of 3-MCPDs by carrying out the decolorization step in the production process of refined oils and fats at a temperature higher than that hitherto known.

[0018] The present invention was completed based on this finding and provides the following methods for producing refined oils and fats, and the refined oils and fats obtained thereby: [1] A method for producing refined oils and fats in which one or more of 3-monochloropropane-1,2-diols and glycidols are reduced, the method comprising a decolorization step of maintaining an oil or fat at a temperature of 100°C or higher but less than 170°C under reduced pressure for 10 minutes or longer but not exceeding 90 minutes. [2] A method for producing refined oils and fats in which one or more of 3-monochloropropane-1,2-diols and glycidols are reduced, the method comprising a decolorization step of adding clay to an oil or fat at a temperature of 70°C or higher but less than 100°C, heating the oil or fat to a temperature of 100°C or higher but less than 170°C under reduced pressure, and maintaining the oil or fat at a temperature of 100°C or higher but less than 170°C under reduced pressure for 10 minutes or longer but not exceeding 90 minutes. [3] A method for producing refined fats and oils in which one or more of 3-monochloropropane-1,2-diols and glycidols have been reduced, the method comprising a decolorization step of heating fats and oils under reduced pressure to 70°C or higher but lower than 100°C, adding white clay to the fat and oil at 70°C or higher but lower than 100°C, heating the fat and oil under reduced pressure to 100°C or higher but lower than 170°C, and maintaining the fat and oil at a temperature of 100°C or higher but lower than 170°C for 10 minutes or higher but lower than 90 minutes. [4] The method for producing refined fats and oils according to any one of [1] to [3] above, wherein the acidity of the white clay used in the decolorization step is 0.50 to 2.50 (mg KOH / g). The acidity of the white clay is measured and calculated by the following methods (1) to (4). (1) 10.0 g of white clay is weighed into an Erlenmeyer flask, 100 mL of ion-exchanged water is added, and the flask is shaken and allowed to stand, and the water level is marked. (2) Boil this for 5 minutes, leave it to cool, then add ion-exchanged water up to the mark and filter the entire amount to obtain the filtrate. (3) Place 40 mL of the obtained filtrate in another Erlenmeyer flask and add 60 mL of distilled water to obtain 100 mL of sample solution. (4) Titrate the sample solution obtained in (3) with N / 40 potassium hydroxide solution using phenolphthalein as an indicator, and calculate the acidity using the following formula. A: Acidity (KOH mg / g) B: Titration amount (mL) of N / 40 potassium hydroxide solution C: Water content of sample f: Titer of N / 40 potassium hydroxide solution S: Weighed amount of sample (g) [5] The method for producing refined fats and oils according to any one of [1] to [4] above, wherein the decolorization step is carried out on fats and oils that have previously been subjected to a deodorization step once or more. [6] The method for producing refined fats and oils according to any one of [1] to [5] above, comprising, after the decolorization step, a deodorization step at an oil and oil temperature of more than 170°C and not more than 270°C. [7] The method for producing refined fats and oils according to any one of [1] to [6] above, wherein the degree of vacuum in the deodorization step carried out after the decolorization step is 650 Pa or less. [8] A refined fat or oil obtained by the method for producing a refined fat or oil described in any one of [1] to [7] above, wherein the total content of 3-monochloropropane-1,2-diol and its fatty acid esters is 3 ppm by mass or less. [9] A refined fat or oil obtained by the method for producing a refined fat or oil described in any one of [1] to [7] above, wherein the total content of glycidol and its fatty acid esters is 2 ppm by mass or less.

[0019] According to the method for producing refined oils and fats of the present invention, refined oils and fats in which the content of either one or more of 3-MCPDs and glycidols has been sufficiently reduced can be efficiently obtained.

[0020] The present invention will be described in detail below with reference to preferred embodiments thereof. The present invention is not limited to the following description, and each component can be appropriately modified within the scope of the present invention.

[0021] [Method for producing refined oils and fats] The present invention relates to a method for producing refined oils and fats having reduced contents of 3-MCPDs and glycidols. The method for producing refined oils and fats of the present invention (hereinafter also simply referred to as the "production method of the present invention") includes a bleaching step of maintaining the oil and fat at a temperature of 100°C or higher and 170°C or lower under reduced pressure for 10 minutes or longer and 90 minutes or shorter (hereinafter also simply referred to as the "bleaching step of the present invention" or "bleaching step").

[0022] - Reduced Pressure Conditions in the Bleaching Step - In the production method of the present invention, the bleaching step is carried out under reduced pressure.

[0023] The term "under reduced pressure" generally refers to a state in which the pressure in the system is lower than atmospheric pressure (1013 hPa). However, the reduced pressure condition (degree of reduced pressure) in the decolorization step of the present invention is preferably 2.0 × 10 ４ Pa or less, more preferably 1.8 × 10 ４ Pa or less, more preferably 1.6 × 10 ４ Pa or less, particularly preferably 1.5 × 10 ４ The lower limit is not particularly limited, but is preferably 1.0 × 10 ２ Pa or more or 5.0 x 10 ２ Pa or more, more preferably 1.0 × 10 ３ Pa or more or 5.0 x 10 ３ Pa or more, more preferably 7.0 × 10 ３ Pa or more or 1.0 x 10 ４ Pa or more.

[0024] The above-mentioned reduced pressure state can be achieved, for example, by evacuating the system using a vacuum pump.

[0025] - Temperature of oil or fat in the bleaching step - The production method of the present invention is characterized in that the temperature of the oil or fat in the bleaching step (bleaching temperature) is set to 100° C. or higher and 170° C. or lower. By performing the bleaching step under these temperature conditions, refined oil or fat with reduced amounts of 3-MCPDs and glycidols can be obtained.

[0026] As mentioned above, exposing oils to high temperatures at each stage of the production process of refined oils has been avoided because it increases the content of 3-MCPDs. In contrast, the present invention is based on the discovery that the content of 3-MCPDs can be significantly reduced by performing the decolorization process in the production of refined oils at a temperature higher than previously known temperatures (for example, YH Hui (1996). "Bailey's Industrial Oil and Fat Products: Fifth Edition Volume 4 Edible Oil and Fat Products Processing Technology," p. 201, recommends a temperature of 75 to 85°C). This finding was initiated by a finding that was unexpected from the conventional understanding of the technology.

[0027] From the viewpoint of more efficiently reducing the contents of 3-MCPDs and glycidols in the refined oil or fat, the temperature of the oil or fat in the decolorization step is preferably 125°C or higher, more preferably 130°C or higher, even more preferably 135°C or higher or 140°C or higher, and the upper limit thereof is preferably 165°C or lower, more preferably 160°C or lower, even more preferably 155°C or lower.

[0028] - Bleaching Step Duration (Bleaching Time) - In the production method of the present invention, the bleaching step is carried out by maintaining the oil or fat at the above-mentioned temperature for 10 minutes to 90 minutes. By setting the bleaching step duration (bleaching time) within the above range, refined oil or fat with reduced amounts of 3-MCPDs and glycidols can be obtained.

[0029] In the bleaching step of the present invention, the bleaching time is preferably 15 minutes or more, more preferably 20 minutes or more, and even more preferably 25 minutes or more, from the viewpoint of efficiently reducing the contents of 3-MCPDs and glycidols, and the upper limit is preferably 75 minutes or less, more preferably 60 minutes or less, and even more preferably 45 minutes or less. The starting point for calculating the bleaching time is the time when the temperature of the oil or fat (bleaching temperature) arbitrarily set within the above range is reached. Furthermore, it is preferable to heat the oil or fat with stirring during the bleaching step.

[0030] In the production method of the present invention, the decolorization step is preferably carried out in a state where the fat and oil are in contact with each other by adding white clay to the fat and oil, etc. Although details will be described later, in the production method of the present invention, it is preferable to bring the fat and oil into contact with each other before the fat and oil reaches the decolorization temperature.

[0031] The white clay that can be preferably used in the production method of the present invention will now be described.

[0032] -White clay- Examples of white clay that can be used in the production method of the present invention include naturally occurring acid clay (montmorillonite clay) and activated clay obtained by subjecting such acid clay to an acid treatment with an inorganic acid such as sulfuric acid or hydrochloric acid.

[0033] In particular, in the present invention, it is preferable to use activated clay which has a porous structure with a large specific surface area due to acid treatment. Although it varies depending on the degree of acid treatment, the specific surface area of ​​activated clay is 50 m ２ / g~400m ２ / g is preferred.

[0034] From the viewpoint of efficiently reducing 3-MCPDs and glycidols, the acidity (KOH mg / g) of the white clay is preferably 2.50 or less, more preferably 2.00 or less, and even more preferably 1.50 or less, and the lower limit thereof is preferably 0.50 or more, more preferably 0.55 or more, and even more preferably 0.60 or more, 0.70 or more, or 0.80 or more. Therefore, in one embodiment, the acidity of the white clay used in the decolorization step is 0.50 to 2.50 (KOH mg / g).

[0035] In the present invention, the acidity of white clay is measured and calculated by the following methods (1) to (4). (1) 10.0 g of white clay is weighed into an Erlenmeyer flask, 100 mL of ion-exchanged water is added, and the mixture is shaken and allowed to stand, and the water level is marked. (2) This is boiled for 5 minutes, allowed to cool, and then ion-exchanged water is added up to the mark, and the entire amount is filtered to obtain a filtrate. (3) 40 mL of the obtained filtrate is placed in another Erlenmeyer flask, and 60 mL of distilled water is added to obtain a 100 mL sample solution. (4) The sample solution obtained in (3) is titrated with N / 40 potassium hydroxide solution using phenolphthalein as an indicator, and the acidity is calculated using the following formula.

[0036] A: Acidity (KOH mg / g) B: Titration volume (mL) of N / 40 potassium hydroxide solution C: Water content of sample f: Titer of N / 40 potassium hydroxide solution S: Weight of sample (g) (Here, C is the water content (% by mass) in the clay sample, and S is the weight (g) of the clay sample.)

[0037] Activated clay generally contains SiO ２ , Al ２ O ３ , Fe ２ O ３ , CaO, MgO, etc., but SiO ２ and Al ２ O ３ Mass ratio (SiO ２ / Al ２ O ３ The ratio is preferably in the range of 3 to 12, more preferably in the range of 4 to 10. ２ O ３ A composition containing 1 mass % to 5 mass % of CaO, 0 mass % to 1.5 mass % of CaO, and 1 mass % to 7 mass % of MgO is preferred.

[0038] Commercially available acid clay products include Mizuka Ace #20, Mizuka Ace #300, Mizuka Ace #400, and Mizurite (all manufactured by Mizusawa Industrial Chemicals, Ltd.), and commercially available activated clay products include Galleon Earth V2R, Galleon Earth V2, Galleon Earth NVZ, and Galleon Earth NV (all manufactured by Mizusawa Industrial Chemicals, Ltd.).

[0039] The shape of the white clay is not particularly limited, and it can take various shapes, such as powder, lumps, beads, pellets, etc. From the viewpoint of increasing the contact area with the oil or fat, the white clay is preferably in powder form.

[0040] In the production method of the present invention, from the viewpoint of sufficiently reducing 3-MCPDs and glycidols, the amount of clay used is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.75 parts by mass or more, relative to 100 parts by mass of fats and oils, and the upper limit thereof is preferably 8.0 parts by mass or less, more preferably 7.5 parts by mass or less, and even more preferably 7.0 parts by mass or less, relative to 100 parts by mass of fats and oils.

[0041] - Conditions for Addition of White Clay - In the production method of the present invention, the temperature of the oil or fat when the white clay is added is not particularly limited, but is preferably 70°C or higher, from the viewpoint of facilitating the production of refined oils and fats with reduced contents of 3-MCPDs and glycidols, and of facilitating the production of refined oils and fats with a good flavor and color. The temperature of the oil or fat when the white clay is added is more preferably 75°C or higher, even more preferably 80°C or higher, and particularly preferably 85°C or higher, with the upper limit being less than 100°C. Therefore, in a preferred embodiment, the temperature of the oil or fat when the white clay is added is 70°C or higher and lower than 100°C, more preferably 75°C or higher and lower than 100°C, even more preferably 80°C or higher and lower than 100°C, and particularly preferably 85°C or higher and lower than 100°C.

[0042] In the production method of the present invention, when the fat or oil used is solid at room temperature (25°C) when heating the fat or oil to the above temperature, it is preferable to melt the fat or oil and then further heat it to a temperature within the above range.

[0043] When heating the fat or oil to the temperature range above where the clay can be added, the fat or oil may be heated under aerobic conditions, anaerobic conditions, or reduced pressure. From the viewpoint of suppressing oxidation of the fat or oil during production, heating under anaerobic conditions or reduced pressure is preferred, and heating under reduced pressure is more preferred. The reduced pressure conditions in this case may be the same as those described above in the "reduced pressure conditions in the bleaching step."

[0044] Furthermore, when adding the white clay to the oil or fat, it may be added in an open state or under reduced pressure, but from the viewpoint of preventing oxidation of the oil or fat and making the flavor of the resulting refined oil or fat preferable, it is preferable to add the white clay to the oil or fat under reduced pressure. The reduced pressure conditions in this case may be the same as those explained above in the "Reduced pressure conditions in the decolorization step."

[0045] When adding white clay in a state open to the atmosphere, if the oil or fat is heated under reduced pressure to 70°C or higher but lower than 100°C, from the viewpoint of minimizing oxidation of the oil or fat during the production process of the refined oil or fat and from the viewpoint of ensuring that the flavor of the resulting refined oil or fat is favorable, it is preferable to introduce an inert gas (e.g., nitrogen gas) into the system while maintaining the oil or fat temperature, release the reduced pressure, and then introduce air to make the system open to the atmosphere.

[0046] As described above, in one embodiment, the production method of the present invention includes a decolorization step of maintaining the oil or fat at a temperature of 100°C or higher and 170°C or lower under reduced pressure for 10 minutes or higher and 90 minutes or lower.

[0047] In a preferred embodiment, the production method of the present invention includes a decolorization step of adding white clay to fats and oils at a temperature of 70°C or higher but lower than 100°C, heating the fats and oils under reduced pressure to a temperature of 100°C or higher but lower than 170°C, and maintaining the fats and oils at a temperature of 100°C or higher but lower than 170°C under reduced pressure for 10 minutes or higher but lower than 90 minutes.

[0048] In a more preferred embodiment, the production method of the present invention includes a decolorizing step of heating an oil or fat to 70°C or higher but lower than 100°C under reduced pressure, adding white clay to the oil or fat at 70°C or higher but lower than 100°C, heating the oil or fat to 100°C or higher but lower than 170°C under reduced pressure, and maintaining the oil or fat at a temperature of 100°C or higher but lower than 170°C under reduced pressure for 10 minutes or higher but lower than 90 minutes.

[0049] -Method of Bleaching Step- In the production method of the present invention, the bleaching step can be carried out by any method, and either a batch method or a continuous method may be used.

[0050] A specific example of a method for carrying out the decolorization step in a batchwise manner is to add white clay to the fat or oil to be subjected to the decolorization step placed in a heat-resistant container, heat the fat or oil to the decolorization temperature, hold the fat or oil at the decolorization temperature for a certain period of time, and then filter the white clay from the fat or oil. A specific example of a method for carrying out the decolorization step in a continuous manner is to fill a filter or column with white clay and pass the fat or oil through the filter or column.

[0051] Among these, the decolorization step is preferably carried out in a batch system, since it allows a large amount of oil to be treated at once and a large amount of refined oil to be produced at once.

[0052] When the decolorization step is performed in a batch system, for example, the following techniques (1) to (3) can be used. (1) A method in which white clay is added to oils and fats at room temperature (10°C to 30°C: particularly 25°C), followed by heating under reduced pressure until the oil and fat temperature reaches 100°C to 170°C, and then maintaining the oil and fat temperature at 100°C to 170°C under reduced pressure for 10 to 90 minutes. (2) A method in which white clay is added to the oil and fat at 70°C to 100°C under reduced pressure (i.e., the temperature at which most oils and fats, including extremely hardened oils, melt and become liquid), followed by heating under reduced pressure until the oil and fat temperature reaches 100°C to 170°C, followed by maintaining the oil and fat temperature at 100°C to 170°C under reduced pressure for 10 to 90 minutes. (3) A method for carrying out a decolorization step in which fats and oils are heated under reduced pressure until the temperature is 100°C or higher and 170°C or lower, white clay is added to the fats and oils at 100°C or higher and 170°C or lower, and the pressure is reduced again while maintaining the fat and oil temperature at 100°C or higher and 170°C or lower, and the fat and oil temperature is maintained at 100°C or higher and 170°C or lower under reduced pressure for 10 minutes to 90 minutes.

[0053] In the above methods (1) to (3), the preferred values ​​and ranges of the reduced pressure conditions (degree of reduced pressure) are as explained above in the "Reduced pressure conditions in the bleaching step" and the like, and the preferred values ​​and ranges of the bleaching temperature and bleaching time are as explained above in the "Temperature of oils and fats in the bleaching step" and "Time of the bleaching step (bleaching time)". In the above method (2), the preferred values ​​and ranges of the temperature when adding white clay to the oils and fats are as explained above in the "Conditions for adding white clay".

[0054] Any of the above methods (1) to (3) can reduce the content of one or more of 3-MCPDs and glycidols in the refined oil or fat obtained, but from the viewpoint of producing a refined oil or fat having a good flavor and an excellent color tone, the method (2) is preferably selected.

[0055] - Deodorizing Step - From the viewpoint of obtaining refined oils and fats having a good flavor and color tone, the production method of the present invention preferably includes a deodorizing step after carrying out the above-described decolorizing step of the present invention.

[0056] The deodorization step is preferably carried out at an oil / fat temperature of more than 170°C and not more than 270°C, from the viewpoint of reducing the contents of 3-MCPDs and glycidols in the resulting refined oil / fat, or suppressing an increase in said contents. Therefore, in one embodiment, the production method of the present invention includes a deodorization step at an oil / fat temperature of more than 170°C and not more than 270°C, after the bleaching step of the present invention. Hereinafter, such a deodorization step may be simply referred to as the "deodorization step of the present invention."

[0057] From the viewpoint of producing refined oils and fats having a low content of 3-MCPDs and glycidol and a good flavor and color tone, the temperature of the oil or fat in the deodorization step (deodorization temperature) is preferably 180°C or higher, more preferably 190°C or higher, even more preferably 200°C or higher or 210°C or higher, and the upper limit thereof is preferably 270°C or lower, more preferably 260°C or lower, even more preferably 250°C or lower or 240°C or lower.

[0058] The deodorizing step is preferably carried out under reduced pressure, and the reduced pressure conditions are preferably 8.0 × 10 ２ Pa or less, more preferably 6.5 × 10２ Pa or less or 5.0 x 10 ２ Pa or less, and more preferably 2.5 × 10 ２ Pa or less.

[0059] In the present invention, the deodorization step can be carried out by a conventional method, and the method is not particularly limited. As a specific example of the deodorization method, a deodorization treatment by reduced pressure steam distillation in which water vapor and fats and oils are brought into contact with each other under reduced pressure will be described below.

[0060] The temperature of the oil or fat when contacting with steam in reduced pressure steam distillation is as described above, and may be set to preferably 190°C or higher and 270°C or lower, more preferably 200°C or higher and 270°C or lower, even more preferably 210°C or higher and 250°C or lower, and particularly preferably 210°C or higher and 240°C or lower.

[0061] The contact time between the steam and the oil or fat during reduced pressure steam distillation may be set to preferably 30 minutes or more and 180 minutes or less, more preferably 30 minutes or more and 150 minutes or less, and even more preferably 30 minutes or more and 120 minutes or less.

[0062] The amount of steam injected in the reduced pressure steam distillation may be set to preferably 1% by mass or more and 5% by mass or less, more preferably 1% by mass or more and 4% by mass or less, and even more preferably 1.5% by mass or more and 4% by mass or less, based on 100% by mass of the oil or fat.

[0063] -Other Steps- The production method of the present invention may include steps other than the above-mentioned bleaching step and deodorizing step.

[0064] Examples of processes other than the bleaching process and the deodorizing process include a degumming process for removing phospholipids, a deacidification process for removing free fatty acids, and a dewaxing process for removing wax. The degumming process, deacidification process, and dewaxing process can be carried out by conventional methods in oil and fat refining. The conditions and order of the degumming process, deacidification process, and dewaxing process are not particularly limited, and they may be carried out under conditions and in an order normally established for the production of refined oils and fats, but it is preferable that they be carried out at least before the bleaching process of the present invention described above.

[0065] The production method of the present invention may include another bleaching step in addition to the bleaching step of the present invention described above. The conditions of the other bleaching step may be the same as or different from those of the bleaching step of the present invention. The other bleaching step may be performed before or after the bleaching step of the present invention. The number of other bleaching steps is not particularly limited. In this specification, when another bleaching step is performed n times before the bleaching step of the present invention, the bleaching step of the present invention may be referred to as the "n+1th bleaching step." As an example of a case where another bleaching step is performed n times before the bleaching step of the present invention, the oil or fat used in the production method of the present invention may be the aforementioned RBD oil or NBD (Neutralized Bleached Deodorized) oil, which is an oil or fat refined by chemical refining.

[0066] The production method of the present invention may include another deodorization step in addition to the deodorization step of the present invention described above. The conditions of the other deodorization step may be the same as or different from those of the deodorization step of the present invention. The other deodorization step may be carried out before the deodorization step of the present invention, or may be carried out after the deodorization step of the present invention. The number of other deodorization steps is not particularly limited. In this specification, when another deodorization step is carried out n times before the deodorization step of the present invention, the deodorization step of the present invention may be referred to as the "n+1th deodorization step." When another deodorization step is carried out n times before the deodorization step of the present invention, for example, the above-mentioned RBD oils and NBD oils may be used as the oils and fats used in the production method of the present invention.

[0067] - Raw material oils and fats - Next, raw material oils and fats (oils and fats to be refined) to which the production method of the present invention can be applied will be described.

[0068] The production method of the present invention can be applied to edible oils and fats without any particular limitation. Examples of edible oils and fats include vegetable oils such as palm oil, palm kernel oil, coconut oil, corn oil, olive oil, cottonseed oil, soybean oil, rapeseed oil, rice oil, sunflower oil, safflower oil, cocoa butter, shea butter, mango kernel oil, sal fat, and illipe fat, and animal oils and fats such as beef tallow, milk fat, lard, fish oil, and whale oil, as well as processed oils and fats obtained by subjecting these oils and fats to one or more treatments selected from hydrogenation, fractionation, and interesterification. The production method of the present invention may be applied to a single oil and fat selected from these, or to a mixed oil and fat obtained by combining two or more types.

[0069] The production method of the present invention is preferably applied to palm-based fats and oils, as the effects thereof are particularly pronounced. In the present invention, palm-based fats and oils refer to palm oil, palm kernel oil, and fats obtained by subjecting palm oil or palm kernel oil to one or more physical or chemical treatments selected from hydrogenation, fractionation, interesterification, etc. Regardless of which palm-based fat or oil is selected, the production method of the present invention can produce fats and oils with extremely low contents of 3-MCPDs and glycidols.

[0070] As described above, 3-MCPDs can be produced particularly in the deodorization process of fats and oils. Therefore, from the viewpoint of fully obtaining the effects of the production method of the present invention, the raw fats and oils used in the production method of the present invention are preferably fats and oils that have been previously subjected to a deodorization process at least once. When fats and oils that have previously been subjected to a deodorization process at least once are used as the raw fat and oil, the number of deodorization processes previously performed on the raw fat and oil is not particularly limited, but from the viewpoint of avoiding deterioration of the fat and oil, it is preferably 5 times or less, more preferably 3 times or less, and even more preferably 2 times or less. The treatment conditions for the preliminary deodorization process may be different from or the same as the treatment conditions for the deodorization process of the present invention described above.

[0071] As the oils and fats that have been previously subjected to the deodorization process at least once, RBD oils and fats, which are obtained by physical refining and have been previously subjected to decolorization and deodorization treatments, or NBD oils and fats, which are obtained by chemical refining and have been previously subjected to decolorization and deodorization treatments, can be suitably selected.

[0072] -Refined fats and oils obtained by the production method of the present invention- The refined fats and oils obtained by the production method of the present invention are characterized by having a low content of either one or more of 3-MCPDs and glycidols.

[0073] In one embodiment, the refined fat or oil obtained by the production method of the present invention is characterized by a low content of 3-MCPDs in the fat or oil. For example, when the production method of the present invention is applied to a raw fat or oil having a total content of 3-MCPDs of more than 3 ppm by mass, the total content of 3-MCPDs in the obtained refined fat or oil can be preferably 3 ppm by mass or less, more preferably 2.5 ppm by mass or less. Furthermore, when the production method of the present invention is applied to a raw fat or oil having a total content of 3-MCPDs of less than 3 ppm by mass, the content of 3-MCPDs in the obtained refined fat or oil can be further reduced.

[0074] In one embodiment, the reduction rate of 3-MCPDs by the production method of the present invention is preferably 5% or more, more preferably 10% or more, and even more preferably 15% or more, 20% or more, 25% or more, or 30% or more. The reduction rate of 3-MCPDs is calculated using the following formula: Reduction rate of 3-MCPDs (%) = (content of 3-MCPDs in raw oil / fat - content of 3-MCPDs in the obtained refined oil / fat) / (content of 3-MCPDs in raw oil / fat) x 100

[0075] The reduction rate of 3-MCPDs indicates the extent to which the content of 3-MCPDs has been reduced by undergoing the bleaching step and deodorizing step of the present invention, based on the content of 3-MCPDs in the raw oil or fat (the oil or fat before the bleaching step of the present invention).

[0076] In one embodiment, the refined fat or oil obtained by the production method of the present invention is characterized by a low content of glycidols in the fat or oil. For example, when the production method of the present invention is applied to a raw fat or oil having a total content of glycidols of more than 6 ppm by mass, the total content of glycidols in the refined fat or oil obtained can be preferably 2 ppm by mass or less, more preferably 1 ppm by mass or less. Furthermore, when the production method of the present invention is applied to a raw fat or oil having a total content of glycidols of less than 6 ppm by mass, the content of glycidols in the refined fat or oil obtained can be further reduced.

[0077] In one embodiment, the reduction rate of glycidols by the method for producing refined oils and fats of the present invention may be preferably 60% or more, more preferably 70% or more, even more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. The reduction rate of glycidols is calculated using the following formula: Reduction rate of glycidols (%) = (glycidol content in raw oil and fat - glycidol content in obtained refined oil and fat) / (glycidol content in raw oil and fat) x 100

[0078] The reduction rate of glycidols indicates the extent to which the content of glycidols can be reduced by undergoing the bleaching process and deodorizing process of the present invention, based on the content of glycidols in the raw oil or fat (the oil or fat before the bleaching process of the present invention).

[0079] Known methods for quantifying the content of 3-MCPDs or glycidols in fats and oils include direct analysis and indirect analysis, which differ in principle. In the present invention, either method may be used; however, it is preferable to quantify 3-MCPDs or glycidols using indirect analysis, as this method requires fewer types of standard substances and is more economical. For example, as a simple indirect analysis method, the method described in Japanese Patent No. 5,864,278 or Oleo Science, Vol. 17, No. 4 (2017), pp. 171-178, or methods equivalent thereto, can be used. This method involves hydrolyzing the fatty acid ester of 3-MCPD or glycidol in fats and oils to convert it to 3-MCPD or glycidol, which is then derivatized with phenylboric acid, and then measuring the content by GC-MS. Measurement conditions by GC-MS can be, for example, the conditions described in the section (Quantification of the Content of 3-MCPDs and Glycidols) in the Examples section of this specification.

[0080] In one embodiment, the refined oils and fats obtained by the production method of the present invention are characterized by a low acid value (AV) and a good flavor. For example, from the viewpoint of obtaining oils and fats with a good flavor, the acid value (AV) of the refined oils and fats obtained by the production method of the present invention is preferably 0.5 or less, more preferably 0.4 or less, even more preferably 0.3 or less, and particularly preferably 0.2 or less. The acid value of an oil and fat is the number of mg of potassium hydroxide (mg KOH / g) required to neutralize the free fatty acids present in 1 g of the oil and fat. The acid value of an oil and fat can be measured, for example, by the method set forth in Standard Methods for the Analysis of Fats, Oils, and Related Materials (2013 Edition) 2.3.1-2013 established by the Japan Oil Chemists' Society.

[0081] In one embodiment, the refined oils and fats obtained by the production method of the present invention are characterized by a low peroxide value (POV) and a good flavor. For example, from the viewpoint of obtaining a good-flavored oil and fat, the peroxide value (POV) of the refined oil and fat obtained by the production method of the present invention is preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.5 or less, 0.4 or less, 0.3 or less, or 0.2 or less. The peroxide value (POV) of an oil and fat is the number of milliequivalents (meg / kg) of iodine liberated when peroxides present in 1 kg of the oil and fat are reacted with potassium iodide. The peroxide value (POV) of an oil and fat can be measured, for example, by the method set forth in 2.5.2 of the Standard Methods for Analysis of Fats, Oils, and Related Materials (2013 edition) established by the Japan Oil Chemists' Society.

[0082] In one embodiment, the refined oil or fat obtained by the production method of the present invention is characterized by a good color tone of the oil or fat. For example, the color tone of the refined oil or fat obtained by the production method of the present invention, as measured by the Lovibond method (using a 5 1 / 4-inch cell), is preferably Y (yellow) or less than 25 and R (red) or less than 2.5, and more preferably Y (yellow) or less than 20 and R (red) or less than 2.0. The color tone of the refined oil or fat (Lovibond method) can be measured, for example, by the method set forth in 2.2.1.1 of the Standard Test Methods for the Analysis of Fats, Oils, and Related Materials (2013 edition) established by the Japan Oil Chemists' Society.

[0083] The refined oils and fats obtained by the production method of the present invention can be used, for example, in the production of foods and beverages. Foods and beverages using the oils and fats obtained by the production method of the present invention are characterized in that the content of 3-MCPDs is kept lower than that of foods and beverages using conventional oils and fats. In one embodiment, foods and beverages using the oils and fats obtained by the production method of the present invention can be characterized in that the content of glycidols is kept lower than that of foods and beverages using conventional oils and fats.

[0084] Examples of foods and beverages include oil- and fat-processed foods such as margarine, shortening, fat spreads, flavored fat spreads, dressings, mayonnaise, frozen desserts, oils and fats for sprays, oils and fats for frying, oils and fats for chocolate, and oils and fats for batters, as well as foods and beverages that use oils and fats from confectionery and bread ingredients such as flour paste and bean paste, Western sweets, Japanese sweets, bread, snacks, curry, stew, gratin, seasonings, instant cooked foods, processed livestock products, processed seafood products, and processed vegetables.

[0085] The present invention will be described in further detail below with reference to examples. In the following, "mass %" and "mass ppm" may be simply referred to as "%" and "ppm". In the following description, unless otherwise specified, the temperature conditions are room temperature (25°C), and unless otherwise specified, the pressure conditions are atmospheric pressure (1013 hPa).

[0086] In the following examples and comparative examples, RBD palm oil (manufactured by ISF) obtained by physically refining crude palm oil was used, which was an oil or fat (n=1) that had been subjected to the first bleaching step and the first deodorizing step. There were four lots of RBD palm oil used as the raw material, and these are referred to as RBD-PO (A), RBD-PO (B), RBD-PO (C), and RBD-PO (D). Furthermore, Galleon Earth V2R manufactured by Mizusawa Industrial Chemicals, Ltd. was used as the activated clay. The acidity of the activated clay used in the study was 0.65 (KOH mg / g).

[0087] <Study 1> In Study 1, the temperature conditions and the amount of clay added in the decolorization step were changed, and the contents of 3-MCPDs and glycidols in the resulting refined oil were measured to evaluate the degree of reduction.

[0088] Example 1 Heated and melted RBD palm oil (lot: RBD-PO(B)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 150°C under a reduced pressure of 133 hPa, and then nitrogen gas was introduced to release the reduced pressure. The pressure was then released to the atmosphere to return to atmospheric pressure, and 2.0% by mass of activated clay was added relative to 100% by mass of RBD palm oil at 150°C. After the addition of the activated clay, the pressure was reduced again and heating was carried out under reduced pressure, adjusting the oil temperature to 150°C, and bleaching treatment was carried out while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0089] After the decolorization step, the oil from which the activated clay had been filtered was subjected to a second deodorization step. In the second deodorization step, steam distillation (amount of steam injected: 3% by mass relative to 100% by mass of the oil) was performed at 230 ° C. for 90 minutes under a reduced pressure of 210 Pa to obtain refined oil Ex-1.

[0090] Example 2 Heated and melted RBD palm oil (lot: RBD-PO(C)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, then opened to the atmosphere and returned to atmospheric pressure, and 2.0% by mass of activated clay was added relative to 100% by mass of RBD palm oil at 90°C. After the addition of activated clay, the pressure was reduced again to 133 hPa, and heating was performed under reduced pressure, adjusting the oil temperature to 150°C, and bleaching treatment was performed while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0091] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-2.

[0092] Example 3 Heated and dissolved RBD palm oil (lot: RBD-PO(D)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of the activated clay, the pressure was reduced again to 133 hPa, and heating was performed under reduced pressure, adjusting the oil temperature to 150°C. The bleaching treatment was performed while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0093] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-3.

[0094] Example 4 Refined fat / oil Ex-4 was obtained in the same manner as in Example 1, except that the amount of activated clay added was 4.0% by mass relative to 100% by mass of RBD palm oil.

[0095] Example 5 Refined fat / oil Ex-5 was obtained in the same manner as in Example 1, except that the amount of activated clay added was 6.0% by mass relative to 100% by mass of RBD palm oil.

[0096] Example 6 Heated and melted RBD palm oil (lot: RBD-PO(A)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of activated clay, the pressure was reduced again and the oil was heated under a reduced pressure of 133 hPa, and the oil temperature was adjusted to 105°C. The bleaching treatment was then carried out under a reduced pressure of 133 hPa for 30 minutes while stirring.

[0097] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-6.

[0098] Example 7 Heated and melted RBD palm oil (lot: RBD-PO(A)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of activated clay, the pressure was reduced again to 133 hPa, and heating was performed under reduced pressure, adjusting the oil temperature to 120°C. The bleaching treatment was performed while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0099] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-7.

[0100] Example 8 Heated and melted RBD palm oil (lot: RBD-PO(D)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of activated clay, the oil was again heated under a reduced pressure of 133 hPa to adjust the oil temperature to 135°C, and bleaching treatment was carried out while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0101] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-8.

[0102] Example 9 Heated and melted RBD palm oil (lot: RBD-PO(B)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of activated clay, the oil was again heated under a reduced pressure of 133 hPa, and the temperature of the oil was adjusted to 165°C. The bleaching treatment was then performed while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0103] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil Ex-9.

[0104] Comparative Example 1 Heated and melted RBD palm oil (lot: RBD-PO(B)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of the activated clay, the pressure was reduced again and heating was continued under reduced pressure, adjusting the oil temperature to 90°C. A bleaching treatment was then performed under a reduced pressure of 133 hPa for 30 minutes while stirring.

[0105] Next, in the same manner as in Example 1, the oil from which the activated clay had been filtered was subjected to a second deodorizing step to obtain refined oil CEx-1.

[0106] (Quantitative Determination of 3-MCPDs and Glycidols) The contents of 3-MCPDs and glycidols in the obtained refined oil were quantified using an indirect analytical method (indirect quantitative method). The contents of 3-MCPDs and glycidols in RBD palm oil as a raw material were also quantified using the same method.

[0107] Specifically, the fatty acid esters of 3-MCPD in the oils and fats were hydrolyzed to convert them to 3-MCPD, which was then derivatized with phenylboronic acid and then quantified by GC-MS. The GC-MS measurements were performed under the following conditions.

[0108] <Gas chromatograph> Column: VF-5ms Injection volume: 1 uL Injection method: splitless Injection port temperature: 250°C Carrier gas: helium, 1.2 mL / min Column oven: 60°C: 1 min → 60 to 150°C: 10°C / min, 150 to 180°C: 3°C / min, 180 to 300°C: 30°C / min, 300°C: 8 min Total 32 min

[0109] <Mass analysis section> Transfer line: 280°C Ion source temperature: 230°C Quadrupole temperature: 150°C Ionization method: EI, positive ions

[0110] The quantitative results were then substituted into the following formulas to determine the reduction rates of 3-MCPDs and glycidols: Reduction rate of 3-MCPDs (%) = (content of 3-MCPDs in raw RBD palm oil - content of 3-MCPDs in the obtained refined oil) / (content of 3-MCPDs in raw RBD palm oil) x 100 Reduction rate of glycidols (%) = (content of glycidols in raw RBD palm oil - content of glycidols in the obtained refined oil) / (content of glycidols in raw RBD palm oil) x 100

[0111] (Measurement of Acid Value) The acid value (AV) of the obtained refined oil was measured by the method set forth in 2.3.1-2013 of the Standard Methods for Analysis of Fats, Oils and Related Materials (2013 edition) established by the Japan Oil Chemists' Society.

[0112] (Measurement of Peroxide Value) The peroxide value (POV) of the obtained refined oil was measured by the method set forth in 2.5.2 of the Standard Test Methods for Analysis of Fats, Oils and Related Materials (2013 edition) established by the Japan Oil Chemists' Society.

[0113] (Measurement of Color Tone) The color tone of the obtained refined oil was measured using the Lovibond method (using a 5 1 / 4 inch cell) in accordance with the method set forth in 2.2.1.1 of the Standard Methods for Analysis of Fats, Oils, and Related Materials (2013 edition) established by the Japan Oil Chemists' Society.

[0114] (Evaluation of Flavor) The obtained refined oil was adjusted to 60°C, 2 g was measured into a teaspoon, and the oil was directly put in the mouth. In accordance with the evaluation criteria shown below, 12 panelists, who had previously agreed on the evaluation criteria, evaluated whether or not the oil had an unpleasant taste. The average scores are shown in Table 1.

[0115] Evaluation criteria: 10 points: No strange taste when put in the mouth 9 points: Strange taste is felt 2-3 seconds after putting in the mouth 8 points: Strange taste is felt immediately after putting in the mouth

[0116] Table 1 shows the raw material oils and fats by lot, as well as the conditions for the second decolorization step, the conditions for the second deodorization step, the content and reduction rate of 3-MCPDs, the content and reduction rate of glycidols, the measurement results of acid value (AV), the measurement results of peroxide value (POV), the measurement results of color tone, and the evaluation results of flavor for each Example and Comparative Example.

[0117]

[0118] <Study 2> In Study 2, the RBD palm oil used as the raw material was changed, and the contents of 3-MCPDs and glycidols in the resulting refined oil were measured to evaluate the degree of reduction.

[0119] Example 10 A decolorization step was carried out in the same manner as in Example 3, except that RBD-PO (B) was used instead of RBD-PO (D). Then, the oil from which the activated clay had been filtered was subjected to a second deodorization step in the same manner as in Example 1, to obtain refined oil Ex-10.

[0120] The obtained refined oil Ex-10 was evaluated in the same manner as in Study 1. The results are shown in Table 2.

[0121]

[0122] From the results of Studies 1 and 2, it was confirmed that refined oils and fats with low contents of 3-MCPDs and glycidols can be obtained by producing refined oils and fats through a decolorization process in which the oils and fats are maintained at a temperature of 100°C or higher and 170°C or lower for 10 minutes or longer and 90 minutes or shorter under reduced pressure.

[0123] <Study 3> In Study 3, the decompression conditions in the second decolorization step were changed, and the contents of 3-MCPDs and glycidols in the resulting refined oil were measured to evaluate the degree of reduction.

[0124] Example 11 Heated and dissolved RBD palm oil (lot: RBD-PO(E)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay was then added relative to 100% by mass of RBD palm oil at 90°C. After the addition of the activated clay, the pressure was reduced again and heating was continued under reduced pressure until the oil temperature reached 135°C. The bleaching treatment was then performed under a reduced pressure of 133 hPa for 30 minutes while stirring.

[0125] After the decolorization step, the oil from which the activated clay had been filtered was subjected to a second deodorization step. In the second deodorization step, steam distillation (amount of steam blown in 3% by mass relative to 100% by mass of the oil) was performed at 230 ° C. for 90 minutes under a reduced pressure of 150 Pa to obtain refined oil Ex-11.

[0126] Example 12 Refined oil / fat Ex-12 was obtained by refining in the same manner as in Example 11, except that the reduced pressure condition in the second decolorization step was set to 67 hPa.

[0127] Example 13 Heated and melted RBD palm oil (lot: RBD-PO(E)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, and then nitrogen gas was introduced to release the reduced pressure. The pressure was then released to the atmosphere to return to atmospheric pressure, and 2.0% by mass of activated clay was added relative to 100% by mass of RBD palm oil at 90°C. After the addition of the activated clay, the pressure was reduced again and heating was continued under reduced pressure until the oil temperature was adjusted to 150°C. The bleaching treatment was carried out under a reduced pressure of 133 hPa for 30 minutes while stirring.

[0128] After the decolorization step, the oil and fat from which the activated clay had been filtered was subjected to a second deodorization step. In the second deodorization step, steam distillation (amount of steam blown in: 3% by mass relative to 100% by mass of the oil and fat) was performed at 230 ° C. for 90 minutes under a reduced pressure of 150 Pa to obtain refined oil and fat Ex-13.

[0129] Example 14 Refined oil / fat Ex-14 was obtained by refining in the same manner as in Example 13, except that the reduced pressure condition in the second decolorization step was set to 67 hPa.

[0130] The obtained refined fats and oils Ex-11 to 14 were evaluated in the same manner as in Study 1. The results are shown in Table 3.

[0131]

[0132] The results of Study 3 revealed that the reduction rate of 3-MCPDs also changes depending on the reduced pressure conditions in the bleaching step. Furthermore, it was found that this change in reduction rate occurs regardless of the bleaching temperature in the bleaching step.

[0133] In Study 4, the acidity of the activated clay used in the second decolorization step or the decompression conditions in the second deodorization step were changed, and the contents of 3-MCPDs and glycidols in the resulting refined oils and fats were measured to evaluate the degree of reduction. As activated clays with different acidities, different lots of "Galleon Earth V2R" manufactured by Mizusawa Industrial Chemicals, Ltd. were used in the study, and the acidity was measured in advance using the acidity measurement method described above.

[0134] Example 15 Heated and dissolved RBD palm oil (lot: RBD-PO(E)) was subjected to a second bleaching step while stirring. In the second bleaching step, the RBD palm oil was heated to 90°C under a reduced pressure of 133 hPa, nitrogen gas was introduced to release the reduced pressure, and the pressure was then released to the atmosphere to return to atmospheric pressure. 2.0% by mass of activated clay (acidity 0.55 (KOH mg / g)) was then added to 100% by mass of the 90°C RBD palm oil. After the addition of the activated clay, the pressure was reduced again and heating was performed under reduced pressure, adjusting the oil temperature to 150°C, and bleaching treatment was performed while stirring under a reduced pressure of 133 hPa for 30 minutes.

[0135] After the decolorization step, the oil and fat from which the activated clay had been filtered was subjected to a second deodorization step. In the second deodorization step, steam distillation (amount of steam blown in: 3% by mass relative to 100% by mass of the oil and fat) was performed at 230 ° C. for 90 minutes under a reduced pressure of 200 Pa to obtain refined oil and fat Ex-15.

[0136] (Example 16) The activated clay used in the second decolorization step was changed to one with an acidity of 0.65 (KOH mg / g), and the reduced pressure condition in the second deodorization step was changed to 300 Pa. Except for this, refinement was performed in the same manner as in Example 15 to obtain refined oil Ex-16.

[0137] (Example 17) The activated clay used in the second decolorization step was changed to one with an acidity of 1.09 (KOH mg / g), and the reduced pressure condition in the second deodorization step was changed to 300 Pa. Except for this, refinement was performed in the same manner as in Example 15 to obtain refined oil Ex-17.

[0138] (Example 18) The activated clay used in the second decolorization step was changed to one with an acidity of 0.65 (KOH mg / g), and the reduced pressure condition in the second deodorization step was changed to 600 Pa. Except for this, refinement was performed in the same manner as in Example 15 to obtain refined oil Ex-18.

[0139] The obtained refined fats and oils Ex-15 to 18 were evaluated in the same manner as in Study 1. The results are shown in Table 4.

[0140]

[0141] From the results of Study 4, it was found that the reduction rate of 3-MCPDs varies depending on the acidity of the activated clay used in the second decolorization step. It was also found that the reduction rate of 3-MCPDs varies depending on the reduced pressure conditions in the second deodorization step.

Claims

1. A method for producing refined oils and fats in which the content of one or more of 3-monochloropropane-1,2-diols and glycidols is reduced, the method comprising a decolorization step of maintaining the oil and fat at a temperature of 100°C or higher and 170°C or lower under reduced pressure for 10 minutes or higher and 90 minutes or lower.

2. A method for producing refined fats and oils in which the content of one or more of 3-monochloropropane-1,2-diols and glycidols has been reduced, the method comprising a decolorization step of adding white clay to fats and oils at a temperature of 70°C or higher but lower than 100°C, heating the fats and oils to a temperature of 100°C or higher but lower than 170°C under reduced pressure, and maintaining the fats and oils at a temperature of 100°C or higher but lower than 170°C under reduced pressure for 10 minutes to 90 minutes.

3. A method for producing refined fats and oils in which one or more of 3-monochloropropane-1,2-diols and glycidols have been reduced, the method comprising a decolorization step of heating fats and oils under reduced pressure to 70°C or higher but lower than 100°C, adding clay to the fats and oils at 70°C or higher but lower than 100°C, heating the fats and oils under reduced pressure to 100°C or higher but lower than 170°C, and maintaining the fats and oils at a temperature of 100°C or higher but lower than 170°C under reduced pressure for 10 minutes to 90 minutes.

4. The method for producing refined oils and fats according to any one of claims 1 to 3, wherein the acidity of the white clay used in the decolorization step is 0.50 to 2.50 (KOH mg / g). The acidity of the white clay is measured and calculated using the following methods (1) to (4): (1) 10.0 g of white clay is weighed into an Erlenmeyer flask, 100 mL of ion-exchanged water is added, the mixture is shaken, and the mixture is allowed to stand, and the water level is marked. (2) The mixture is boiled for 5 minutes, allowed to cool, and then ion-exchanged water is added up to the mark. The entire amount is filtered to obtain a filtrate. (3) 40 mL of the obtained filtrate is transferred to another Erlenmeyer flask, and 60 mL of distilled water is added to obtain a 100 mL sample solution. (4) The sample solution obtained in (3) is titrated with N / 40 potassium hydroxide solution using phenolphthalein as an indicator, and the acidity is calculated using the following formula: A: Acidity (KOH mg / g) B: Titration volume of N / 40 potassium hydroxide solution (mL) C: Moisture content of sample f: Titer of N / 40 potassium hydroxide solution S: Weight of sample (g) 5. A method for producing refined oils and fats according to any one of claims 1 to 4, wherein the decolorization step is carried out on oils and fats that have previously been subjected to a deodorization step at least once.

6. A method for producing refined oils and fats according to any one of claims 1 to 5, which comprises a deodorization step at an oil and fat temperature of more than 170°C and not more than 270°C after the decolorization step.

7. A method for producing refined oils and fats according to any one of claims 1 to 6, wherein the degree of vacuum in the deodorizing step carried out after the decolorizing step is 650 Pa or less.

8. A refined oil obtained by the method for producing a refined oil according to any one of claims 1 to 7, wherein the total content of 3-monochloropropane-1,2-diol and its fatty acid esters is 3 ppm by mass or less.

9. Refined fats and oils obtained by the method for producing refined fats and oils according to any one of claims 1 to 7, wherein the total content of glycidol and its fatty acid esters is 2 ppm by mass or less.