Process for producing refined oil and fat and process for producing tocopherols

Abstract

The present invention provides a method for producing refined oil and fat, which can reduce the content of glycidol and the like and can suppress the reduction of the content of tocopherols, and a method for producing tocopherols with less impurities. The present invention provides a method for producing refined oil and fat, which includes the following steps: a first distillation step of performing thin film distillation treatment on a raw oil and fat under a first condition; a second distillation step of performing thin film distillation treatment on a first distillate component obtained after the first distillation step under a second condition; a third distillation step of performing thin film distillation treatment on a second residual component obtained after the second distillation step under a third condition; and a mixing step of mixing a first residual component obtained after the first distillation step and a third distillate component obtained after the third distillation step, thereby obtaining a mixed oil, the first to third conditions including prescribed temperature conditions and pressure conditions.

Description

Technical Field

[0001] This invention relates to methods for manufacturing refined oils and fats and methods for manufacturing tocopherols. Background Technology

[0002] Fats and oils contain trace components believed to be related to physiological activity. Examples of such trace components include glycidol, 3-chloropropane-1,2-diol, and their fatty acid esters. While some have pointed out potential nutritional concerns regarding these trace components, levels present in oils and oils, such as vegetable oils, from long-term consumption of food sources are not considered to have an immediate impact on health, and intake standards have not yet been established. However, due to the need for safer fats and oils, various methods have been proposed to reduce the levels of these components.

[0003] Glycidyl ether, 3-chloropropane-1,2-diol, and their fatty acid esters are known to be produced through deodorization processes, and may also be present in trace amounts in common vegetable oils such as deodorized rapeseed oil. Furthermore, diglycerides (Non-Patent Document 1) are known to be contributing factors to 3-chloropropane-1,2-diol, and it is confirmed that they are often present in high concentrations in oils high in diglycerides, particularly refined palm oils (palm oil, palm kernel oil, etc.). Therefore, for example, Patent Document 1 discloses a method for manufacturing refined palm oils including thin-film distillation, wherein the content of the aforementioned components is reduced by adjusting the temperature conditions of the thin-film distillation process.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2017 / 154638

[0007] Non-patent literature

[0008] Non-patent literature 1: LWT-Food Science and Technology 42(2009)1751-1754 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, even if conventional methods can reduce the content of glycidol, 3-chloropropane-1,2-diol, and their fatty acid esters, they may also reduce the content of beneficial components in the oils. Tocopherols are an example of such beneficial components.

[0011] Furthermore, it is difficult to extract only the useful components from the various components (such as glycidol, 3-chloropropane-1,2-diol and their fatty acid esters, as well as useful components such as tocopherols) that have been removed from oils by conventional methods.

[0012] The present invention was made in view of the above circumstances, and its object is to provide a method for manufacturing refined oils that can reduce the content of glycidol, 3-chloropropane-1,2-diol and their fatty acid esters, and can inhibit the reduction of tocopherol content. Furthermore, an object of the present invention is to provide a method for manufacturing tocopherols with fewer impurities.

[0013] Solution for solving the problem

[0014] The inventors have discovered that by performing multiple thin-film distillation processes and adjusting the temperature conditions of each thin-film distillation process in a method for manufacturing refined oils, the aforementioned problems can be solved, thus completing the present invention. Specifically, the present invention provides the following solution.

[0015] (1) A method for manufacturing refined oil, comprising the following steps:

[0016] The first distillation step involves thin-film distillation of the raw oil under the first condition.

[0017] The second distillation step involves performing thin-film distillation on the first distillate obtained after the first distillation step under the second conditions.

[0018] In the third distillation step, the second residual component obtained after the aforementioned second distillation step is subjected to thin-film distillation under third conditions; and,

[0019] The mixing process involves mixing the first residual component obtained after the first distillation process with the third distillate component obtained after the third distillation process to obtain a mixed oil.

[0020] The temperature under the first condition mentioned above is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa.

[0021] Compared to the first condition mentioned above, the second and third conditions mentioned above both have lower temperatures and lower vacuum levels (below 0.1 Pa).

[0022] Compared to the third condition mentioned above, the temperature in the second condition mentioned above is more than 5°C lower and less than 15°C lower.

[0023] (2) A method for manufacturing refined oil, comprising the following steps:

[0024] The first distillation step involves thin-film distillation of the raw oil under the first condition.

[0025] The third distillation step involves performing thin-film distillation on the first distillate obtained after the first distillation step under the third conditions.

[0026] In the second distillation step, the third distillate obtained after the aforementioned third distillation step is subjected to thin-film distillation under second conditions; and,

[0027] The mixing process involves combining the first residual component obtained after the first distillation process with the second residual component obtained after the second distillation process to obtain a mixed oil.

[0028] The temperature under the first condition mentioned above is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa.

[0029] Compared to the first condition mentioned above, the second and third conditions mentioned above both have lower temperatures and lower vacuum levels (below 0.1 Pa).

[0030] Compared to the third condition mentioned above, the temperature in the second condition mentioned above is more than 5°C lower and less than 15°C lower.

[0031] (3) The manufacturing method according to (1) or (2), wherein the temperature of the aforementioned second condition is above 175°C and below 185°C.

[0032] (4) The manufacturing method according to any one of (1) to (3), wherein the temperature of the aforementioned third condition is 185°C or higher and 195°C or lower.

[0033] (5) The manufacturing method according to any one of (1) to (4), wherein the aforementioned raw material oil is an oil that has undergone at least a deodorization process.

[0034] (6) The manufacturing method according to any one of (1) to (5), wherein the aforementioned raw material oil is a palm oil.

[0035] (7) The manufacturing method according to any one of (1) to (6), wherein the aforementioned thin film distillation treatment is a short-path distillation treatment.

[0036] (8) A method for manufacturing tocopherols, comprising the following steps:

[0037] The first distillation step involves thin-film distillation of the raw oil under the first condition.

[0038] The second distillation step involves performing thin-film distillation on the first distillate obtained after the first distillation step under the second conditions.

[0039] In the third distillation step, the second residual component obtained after the aforementioned second distillation step is subjected to thin-film distillation under third conditions; and,

[0040] The recovery process involves recovering the third distillate obtained after the aforementioned third distillation process.

[0041] The temperature under the first condition mentioned above is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa.

[0042] Compared to the first condition mentioned above, the second and third conditions mentioned above both have lower temperatures and lower vacuum levels (below 0.1 Pa).

[0043] Compared to the third condition mentioned above, the temperature in the second condition mentioned above is more than 5°C lower and less than 15°C lower.

[0044] (9) A method for manufacturing tocopherols, comprising the following steps:

[0045] The first distillation step involves thin-film distillation of the raw oil under the first condition.

[0046] The third distillation step involves performing thin-film distillation on the first distillate obtained after the first distillation step under the third conditions.

[0047] In the second distillation step, the third distillate obtained after the aforementioned third distillation step is subjected to thin-film distillation under second conditions; and,

[0048] The recovery process involves recovering the second residual component obtained after the aforementioned second distillation process.

[0049] The first condition mentioned above is a temperature above 250°C and below 290°C, and a vacuum degree below 0.1 Pa.

[0050] Compared to the first condition mentioned above, the second and third conditions mentioned above both have lower temperatures and lower vacuum levels (below 0.1 Pa).

[0051] Compared to the third condition mentioned above, the temperature in the second condition mentioned above is more than 5°C lower and less than 15°C lower.

[0052] The effects of the invention

[0053] According to the present invention, a method for manufacturing refined oils is provided that can reduce the content of glycidyl ether, 3-chloropropane-1,2-diol and their fatty acid esters, and can inhibit the reduction of tocopherol content, and a method for manufacturing tocopherols with fewer impurities is provided. Attached Figure Description

[0054] Figure 1 A diagram illustrating an outline of the manufacturing method of the present invention according to the first embodiment.

[0055] Figure 2 A diagram illustrating the outline of the manufacturing method of the present invention in the second aspect. Detailed Implementation

[0056] The embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[0057] <Methods for Manufacturing Refined Oils>

[0058] The method for manufacturing refined oils of the present invention (hereinafter also referred to as "the manufacturing method of the present invention") includes multiple thin-film distillation processes. In the present invention, "thin-film distillation process" refers to forming the object to be processed into a thin film, heating it under reduced pressure, and then evaporating it. Through this process, distillate components and residual components can be obtained from the object to be processed. "Distillate components" refers to the components separated from the object to be processed by evaporation, and "residual components" refers to the components remaining after the distillate components have been separated from the object to be processed.

[0059] The inventors conducted research and found that if the raw oil is subjected to thin-film distillation at high temperatures (e.g., above 250°C and below 290°C), residual components with reduced contents of glycidyl ether, 3-chloropropane-1,2-diol (hereinafter also referred to as "3-MCPD"), and their fatty acid esters can be obtained. These residual components were found to be useful as refined oils. Furthermore, it was discovered that in these refined oils (residual components), tocopherols, which are useful components, are separated as distillate components, thus significantly reducing the content of tocopherols. It should be noted that in this invention, "tocopherols" refers to the collective term for isomers of tocopherols (α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol) and isomers of tocotrienols (α-tocotrienol, β-tocotrienol, γ-tocotrienol, and δ-tocotrienol).

[0060] Therefore, the inventors conducted in-depth research and found that after thin-film distillation of the raw oil at high temperature, the distillate was further subjected to thin-film distillation at different temperature conditions. As a result, if the obtained components were mixed with refined oil (residual components), refined oil with reduced content of glycidol and the reduction of tocopherol content could be obtained.

[0061] Specifically, the inventors conducted research and discovered that glycidyl ether, 3-MCPD and their fatty acid esters, and tocopherols can be separated by thin-film distillation at different temperature conditions. Specifically, glycidyl ether, 3-MCPD and their fatty acid esters, and tocopherols can be separated from oils by thin-film distillation at high temperature (the first temperature condition described later). Glycidyl ether and its fatty acid esters can be separated from oils by thin-film distillation at low temperature (the second temperature condition described later). 3-MCPD and its fatty acid esters can be separated from oils by thin-film distillation at medium temperature (the third temperature condition described later). The manufacturing method of the present invention utilizes this relationship to perform thin-film distillation in stages under different temperature conditions.

[0062] A summary of the manufacturing method of the present invention is shown below. Figure 1 and 2 The following is a detailed description of the thin-film distillation process and the raw oils in this invention.

[0063] (Raw oils)

[0064] In this invention, "raw material oil" refers to any oil containing tocopherols supplied for the manufacturing method of this invention.

[0065] As raw material oils, the following oils containing tocopherols can be cited: vegetable oils, oils synthesized from glycerol and fatty acids and their fractionated oils, transesterified oils, hydrogenated oils, etc. They can be used alone or in combination of two or more as blended oils.

[0066] Examples of plant-based oils include palm oils, soybean oil, rapeseed oil, high-oleic rapeseed oil, sunflower oil, high-oleic sunflower oil, olive oil, safflower oil, high-oleic safflower oil, corn oil, cottonseed oil, rice oil, sesame oil, perilla oil, flaxseed oil, peanut oil, grapeseed oil, butter, dairy fat, fish oil, and coconut oil.

[0067] Oils and fats are synthesized from glycerol and fatty acids, such as medium-chain triglycerides (MCTs).

[0068] Examples of fractionated oils include those made from palm oil, palm kernel oil, and coconut oil.

[0069] Examples of transesterification oils include transesterification oils of palm oils and other oils, and transesterification oils of medium-chain triglyceride (MCT) oils and vegetable oils.

[0070] Examples of hydrogenated oils include hydrogenated oils of animal and vegetable oils, hydrogenated oils of fractionated animal and vegetable oils, and hydrogenated oils of transesterified oils.

[0071] It should be noted that, from the viewpoint of maximizing the effects of this invention, the raw material oil is preferably an oil that contains a relatively high amount of diglycerides and 3-MCPD. Specifically, examples include palm oils, rice oil, and transesterified oils.

[0072] As palm-based oils, examples include oils derived from palm trees. Specific examples of palm-based oils include palm oil, palm kernel oil, fractionated oils of palm oil, hydrogenated oils of palm kernel oil, hydrogenated oils of palm kernel oil, hydrogenated oils of palm oil fractionated oil, hydrogenated oils of palm kernel oil fractionated oil, and their transesterified oils. It should be noted that fractionated oils of palm oil include super palm oil extract, palm oil extract, palm middle fractions, and palm stearin; fractionated oils of palm kernel oil include palm kernel oil extract and palm kernel stearin.

[0073] There are no particular limitations on the characteristics of palm oils. From the perspective of low unsaturated fatty acid content, low trans fatty acid content, and high oxidative stability, the iodine value is preferably below 65, and more preferably below 58.

[0074] There are no particular limitations on the raw material oils; they can be oils that have undergone refining processes other than thin-film distillation (such as degumming, deacidification, washing, decolorization, deodorization, and fractionation), or they can be unrefined oils. There are no particular limitations on the refining method; both chemical refining and physical refining are acceptable. In chemical refining, crude oil obtained by pressing / extracting plants is subjected to degumming, alkali deacidification, decolorization, dewaxing, and deodorization to obtain refined oils. In physical refining, crude oil is subjected to degumming, deacidification without alkali using distillation or other methods, decolorization, and deodorization to obtain refined oils. It should be noted that oils that have undergone degumming, decolorization, and deodorization processes are called RBD (Refined Bleached Deodorized) oils.

[0075] From the viewpoint that the present invention can easily exert its effect of reducing glycidyl ether, 3-MCPD and their fatty acid esters, the raw material oil is preferably an oil with a high content of glycidyl ether, 3-MCPD and their fatty acid esters. Examples of such oils include those that have undergone a deodorization process (preferably a deodorization process at 200–280°C). RBD oil is more preferably a raw material oil.

[0076] From the perspective of obtaining high purity tocopherols, there are no particular limitations as long as the raw oil undergoes a certain process.

[0077] The raw oil contains glycerides as the main component and also contains tocopherols. Other components may include phytosterols, lecithin, antioxidants, and pigments.

[0078] (First distillation step)

[0079] The first distillation step is a process of thin-film distillation of the raw oil under the first condition. The main purpose of the first distillation step is to separate glycidyl ether, 3-MCPD and their fatty acid esters, as well as tocopherols from the raw oil.

[0080] The temperature for the first condition is above 250°C and below 290°C. Processing the feedstock oil at this high temperature allows for the separation of glycidyl ether, 3-MCPD and their fatty acid esters, as well as tocopherols, resulting in a first residual component and a first distillate. The first residual component mainly comprises oil (triglycerides), preferably composed of oil (triglycerides). The first distillate comprises glycidyl ether, 3-MCPD and their fatty acid esters, as well as tocopherols.

[0081] The lower limit of the temperature for the first condition is preferably 265°C, more preferably 270°C. The upper limit of the temperature for the first condition is preferably 285°C, more preferably 280°C.

[0082] The preferred temperature range for the first condition is any one of the following: above 250°C and below 285°C, above 250°C and below 280°C, above 265°C and below 290°C, above 265°C and below 285°C, above 265°C and below 280°C, above 270°C and below 290°C, above 270°C and below 285°C, or above 270°C and below 280°C.

[0083] The higher the temperature conditions, the easier it becomes to separate glycidol, 3-MCPD and their fatty acid esters from the raw oil.

[0084] In the present invention, the temperature conditions for thin-film distillation processing correspond to the temperature of the evaporation surface of the thin-film distillation apparatus. That is, in the present invention, "the temperature conditions for thin-film distillation processing are 250°C or higher and 290°C or lower" means that the temperature of the evaporation surface of the thin-film distillation apparatus is 250°C or higher and 290°C or lower. For example, in the case of thin-film distillation processing performed in a short-path distillation apparatus, the temperature conditions for thin-film distillation processing correspond to the temperature of the evaporation vessel.

[0085] The vacuum level in the first condition is 0.1 Pa or less. From the viewpoint of obtaining sufficient mean free stroke in the distillation apparatus and further facilitating the removal of high-boiling-point substances, the vacuum level in the first condition is preferably close to 0 (zero) Pa. The vacuum level in the first condition is preferably 0.05 Pa or less, and more preferably 0.01 Pa or less.

[0086] It should be noted that the "vacuum degree" in this invention is expressed using an absolute pressure reference. This value indicates the degree to which an absolute vacuum, taken as zero, approaches the ideal vacuum state (absolute vacuum).

[0087] Following the first distillation step, a second and third distillation step are performed under specified conditions. The second and third distillation steps can be performed either in the order specified. Hereinafter, the method of performing the first, second, and third distillation steps sequentially will be referred to as "Method 1," and the method of performing the first, third, and second distillation steps sequentially will be referred to as "Method 2." An overview of Method 1 is shown below. Figure 1 The summary of method 2 is shown below. Figure 2 .

[0088] (Second distillation step in method 1)

[0089] The second distillation step in Method 1 is a process of performing thin-film distillation on the first distillate obtained after the first distillation step under second conditions. The main purpose of the second distillation step is to separate glycidyl ether and its fatty acid esters from the first distillate.

[0090] Compared to condition 1, the temperature of condition 2 in method 1 is lower, and compared to condition 3 (described later), the temperature is at least 5°C lower and less than 15°C lower. Compared to condition 3, the temperature of condition 2 is preferably at least 8°C lower and less than 12°C lower. Processing the first distillate at this low temperature allows for the separation of fatty acids, glycidyl ethers, and their fatty acid esters as distillate components, resulting in a second residual component and a second distillate. The second residual component mainly contains tocopherols, 3-MCPD, and their fatty acid esters. The second distillate mainly contains fatty acids, glycidyl ethers, and their fatty acid esters.

[0091] The lower limit of the temperature in the second condition of the first method is preferably 175°C, more preferably 178°C. The upper limit of the temperature in the second condition is preferably 185°C, more preferably 184°C, and even more preferably 183°C.

[0092] The preferred temperature range for the second condition in the first method is any one of the following: 175°C or higher and 185°C or lower, 175°C or higher and 184°C or lower, 175°C or higher and 183°C or lower, 178°C or higher and 185°C or lower, 178°C or higher and 184°C or lower, or 178°C or higher and 183°C or lower. To ensure that the second residual component reliably contains tocopherols, the temperature of the second condition is particularly preferably 178°C or higher and 183°C or lower.

[0093] The lower limit of the difference between the second and third conditions in the first method is preferably 8°C, more preferably 10°C. The upper limit of this difference is preferably 14°C, more preferably 12°C.

[0094] The vacuum level in the second condition of the first method is 0.1 Pa or less. From the viewpoint of obtaining sufficient mean free stroke in the distillation apparatus and further facilitating the removal of high-boiling-point substances, the vacuum level in the second condition is preferably close to 0 (zero) Pa. The vacuum level in the second condition is preferably 0.05 Pa or less, and more preferably 0.01 Pa or less.

[0095] (The third distillation step in method 1)

[0096] The third distillation step in Method 1 is a process of thin-film distillation of the second residual component obtained after the second distillation step under a third temperature condition. The main purpose of the third distillation step is to separate 3-MCPD and its fatty acid esters from the second residual component.

[0097] Compared to condition 1, condition 3 in method 1 has a lower temperature, and compared to condition 2, the temperature is 5°C higher but less than 15°C higher. Compared to condition 2, the temperature of condition 3 is preferably 8°C higher but less than 12°C higher. Treating the second residual component at this moderate temperature allows 3-MCPD and its fatty acid esters to be separated as residual components, resulting in a third residual component and a third distillate. The third residual component mainly contains 3-MCPD and its fatty acid esters. The third distillate mainly contains tocopherols.

[0098] The lower limit of the temperature for the third condition in the first method is preferably 185°C, more preferably 186°C, and even more preferably 188°C. The upper limit of the temperature for the third condition is preferably 195°C, and more preferably 193°C.

[0099] The preferred temperature range for the third condition in the first method is any one of the following: 185°C or higher and 195°C or lower, 185°C or higher and 193°C or lower, 184°C or higher and 195°C or lower, 184°C or higher and 193°C or lower, 188°C or higher and 195°C or lower. To ensure that the third residual component reliably contains tocopherols, the temperature of the third condition is particularly preferably 188°C or higher and 193°C or lower.

[0100] In the first method, the vacuum level in the third condition is 0.1 Pa or less. From the viewpoint of obtaining sufficient mean free stroke in the distillation apparatus and further facilitating the removal of high-boiling-point substances, the vacuum level in the third condition is preferably close to 0 (zero) Pa. The vacuum level in the third condition is preferably 0.05 Pa or less, and more preferably 0.01 Pa or less.

[0101] (The third distillation step in method 2)

[0102] The third distillation step in the second method is a process of thin-film distillation of the first distillate obtained after the first distillation step under third conditions. The main purpose of the third distillation step is to separate 3-MCPD and its fatty acid esters from the first distillate.

[0103] Compared to condition 1, condition 3 in method 2 has a lower temperature, and is at least 5°C higher but less than 15°C higher than condition 2. Preferably, the temperature of condition 3 is at least 8°C higher but less than 12°C higher than condition 2. Processing the first distillate at this moderate temperature allows 3-MCPD and its fatty acid esters to be separated as residual components, resulting in a third residual component and a third distillate. The third residual component mainly contains 3-MCPD and its fatty acid esters. The third distillate mainly contains fatty acids, glycidyl ether and its fatty acid esters, and tocopherols.

[0104] The lower limit of the temperature for the third condition in the second method is preferably 185°C, more preferably 186°C, and even more preferably 188°C. The upper limit of the temperature for the third condition is preferably 195°C, more preferably 193°C.

[0105] The preferred temperature range for the third condition in the second method is any one of the following: 185°C or higher and 195°C or lower, 185°C or higher and 193°C or lower, 184°C or higher and 195°C or lower, 184°C or higher and 193°C or lower, 188°C or higher and 195°C or lower. To ensure that the third residual component reliably contains tocopherols, the temperature of the third condition is particularly preferably 188°C or higher and 193°C or lower.

[0106] In the second method, the vacuum level in the third condition is 0.1 Pa or less. From the viewpoint of obtaining sufficient mean free stroke in the distillation apparatus and further facilitating the removal of high-boiling-point substances, the vacuum level in the third condition is preferably close to 0 (zero) Pa. The vacuum level in the third condition is preferably 0.05 Pa or less, and more preferably 0.01 Pa or less.

[0107] (The second distillation step in the second method)

[0108] The second distillation step in the second method is a process of thin-film distillation of the third distillate obtained after the third distillation step under the second conditions. The main purpose of the second distillation step is to separate glycidyl esters and their fatty acid esters from the third distillate.

[0109] Compared to condition 1, the temperature of condition 2 in method 2 is lower, and compared to condition 3, the temperature is at least 5°C lower but less than 15°C lower. Compared to condition 3, the temperature of condition 2 is preferably at least 8°C lower but less than 12°C lower. Processing the third distillate at this low temperature allows glycidyl ether and its fatty acid esters to be separated as distillate components, resulting in a second residual component and a second distillate component. The second residual component mainly contains tocopherols. The second distillate component mainly contains fatty acids, glycidyl ether, and its fatty acid esters.

[0110] The lower limit of the temperature of the second condition in the second method is preferably 175°C, more preferably 178°C. The upper limit of the temperature of the second condition is preferably 185°C, more preferably 184°C, and even more preferably 183°C.

[0111] The preferred temperature range for the second condition in the second method is any one of the following: 175°C or higher and 185°C or lower, 175°C or higher and 184°C or lower, 175°C or higher and 183°C or lower, 178°C or higher and 185°C or lower, 178°C or higher and 184°C or lower, or 178°C or higher and 183°C or lower. To ensure that the second residual component reliably contains tocopherols, the temperature of the second condition is particularly preferably 178°C or higher and 183°C or lower.

[0112] The lower limit of the difference between the second and third temperature conditions in the second method is preferably 8°C, more preferably 10°C. The upper limit of this difference is preferably 14°C, more preferably 12°C.

[0113] The vacuum level in the second condition of the second method is 0.1 Pa or less. From the viewpoint of obtaining sufficient mean free stroke in the distillation apparatus and further facilitating the removal of high-boiling-point substances, the vacuum level in the second condition is preferably close to 0 (zero) Pa. The vacuum level in the second condition is preferably 0.05 Pa or less, and more preferably 0.01 Pa or less.

[0114] (Other conditions in the distillation process)

[0115] In either Method 1 or Method 2, each distillation step is not particularly limited in terms of other conditions as long as the above characteristics are met. As common to all distillation steps, the following examples illustrate other conditions that can be used in this invention.

[0116] Between each distillation step, other refining steps (such as decolorization) may be included, but it is preferable not to include other refining steps (such as decolorization) (that is, the distillation steps are performed continuously).

[0117] The processing time of thin-film distillation refers to the time that the object being processed exists on the evaporation surface of the thin-film distillation apparatus. There is no particular limitation, but from the viewpoint of achieving thorough distillation, it is preferably 1 second or more, and more preferably 3 seconds or more. Furthermore, from the viewpoint of suppressing the thermal impact on the object being processed, the processing time of thin-film distillation is preferably 5 minutes or less, more preferably 3 minutes or less, further preferably 1 minute or less, and most preferably 30 seconds or less.

[0118] As types of thin-film distillation, there are molecular distillation performed under high vacuum (below 0.1 Pa) with the collector positioned at a distance shorter than the mean free path of the evaporating molecules, and short-path distillation with the collector positioned at a distance equal to or before the mean free path of the evaporating molecules. From the viewpoint of high distillation efficiency, short-path distillation is preferred in this invention.

[0119] There are no particular limitations on the thin-film distillation apparatus used in thin-film distillation; various types of evaporators, such as downflow film, centrifugal, rising film, and scraped film evaporators, can be used. From the perspective of shorter residence time of the processed material within the thin-film distillation apparatus and reduced thermal impact on the processed material, scraped film evaporators are preferred. There are no particular limitations on the material of the evaporation surface of the thin-film distillation apparatus; glass or stainless steel can be used.

[0120] (Mixed Process)

[0121] In the first method, the mixing step involves mixing the first residual component with the third distillate component to obtain a mixed oil. In the second method, the mixing step involves mixing the first residual component with the second residual component to obtain a mixed oil. In this invention, this mixed oil is referred to as "refined oil".

[0122] In the first method, the first residual component mainly consists of oils (triglycerides), and the third distillate mainly consists of tocopherols. In the second method, the first residual component mainly consists of oils (triglycerides), and the second residual component mainly consists of tocopherols. Therefore, by mixing them separately, refined oils can be obtained with reduced contents of glycidyl ether, 3-chloropropane-1,2-diol, and their fatty acid esters, while the reduction in tocopherol content is inhibited.

[0123] Refined oils can be circulated directly or supplied to further refining processes. For example, refined oils can be supplied to deodorization processes (preferably processes carried out at lower deodorization temperatures below 200°C).

[0124] Refined oils can be appropriately blended with known ingredients (antioxidants, pigments, emulsifiers, etc.).

[0125] <Specific Contents of Glycidol, 3-Chloropropane-1,2-diol, and Their Fatty Acid Esters in Refined Oils>

[0126] According to the manufacturing method of the present invention, refined oils with reduced contents of glycidyl ether, 3-chloropropane-1,2-diol, and their fatty acid esters can be obtained.

[0127] Furthermore, the manufacturing method according to the present invention can also reduce the acid value and peroxide value of refined oils. Therefore, the manufacturing method according to the present invention can provide highly refined oils.

[0128] The content, acid value, and peroxide value of glycidyl ether, 3-chloropropane-1,2-diol, and their fatty acid esters in the oils and fats are specified using the methods described in the examples.

[0129] <Specific content of tocopherols in refined oils>

[0130] According to the manufacturing method of the present invention, refined oils with reduced and inhibited tocopherol content can be obtained.

[0131] The content of tocopherols in the oil is specified by the method described in the examples.

[0132] <Methods for manufacturing tocopherols>

[0133] As described above, in the first method, the third distillate obtained after the third distillation step mainly contains tocopherols. In the second method, the second residual component obtained after the second distillation step mainly contains tocopherols. Therefore, according to the present invention, by recovering only the third distillate in the first method or the second residual component in the second method, high-purity tocopherols can be obtained.

[0134] Example

[0135] The following examples illustrate the invention in detail, but the invention is not limited to these examples.

[0136] <Production of Refined Oils>

[0137] Refined palm oil was produced using palm oil (iodine value = 52, hereinafter also referred to as "raw palm oil") as the raw material oil, according to the following method. It should be noted that the raw palm oil was obtained by decolorizing RBD palm oil (decolorization conditions: adding 0.65% bleaching clay relative to the oil) and then deodorizing it (deodorization conditions: 245°C, vacuum degree 5-6 Torr). It should be noted that this example is one instance of Method 1.

[0138] (First distillation step)

[0139] The raw material, palm oil, is introduced into a short-path distillation apparatus, model KDL5 (UIC GmbH, evaporation surface 480 cm²).2 650cm of aggregate surface 2 An evaporation surface with a maximum flow rate of 1 L / h was used for thin-film distillation (in this example, short-path distillation) under the conditions shown in Table 1. It should be noted that the residence time of the raw material palm oil in the evaporation surface of the short-path distillation apparatus (i.e., the processing time of the thin-film distillation) was set to a range of 5 seconds or more and 30 seconds or less.

[0140] The residual components (first residual component) and distillate components (first distillate component) were collected after short-path distillation under the above conditions. It should be noted that the distillate percentage (the ratio of distillate components to the total amount of collected residual and distillate components) was 11.8%.

[0141] (Second distillation process)

[0142] The first distillate obtained from the first distillation step is introduced into a short-path distillation apparatus, model KDL5 (manufactured by UIC GmbH, with an evaporation surface of 480 cm²). 2 650cm of aggregate surface 2 An evaporation surface with a maximum flow rate of 1 L / h was used for thin-film distillation (in this example, short-path distillation) under the conditions shown in Table 1. It should be noted that the residence time of the raw material palm oil in the evaporation surface of the short-path distillation apparatus (i.e., the processing time of the thin-film distillation) was set to a range of 5 seconds or more and 30 seconds or less.

[0143] The residual components (second residual component) and distillate components (second distillate component) were collected after short-path distillation under the above conditions. It should be noted that the distillate fraction was 0.24%.

[0144] (Third distillation step)

[0145] The second residual component obtained in the second distillation process is introduced into a short-path distillation apparatus, model KDL5 (manufactured by UIC GmbH, with an evaporation surface of 480 cm²). 2 650cm of aggregate surface 2 An evaporation surface with a maximum flow rate of 1 L / h was used for thin-film distillation (in this example, short-path distillation) under the conditions shown in Table 1. It should be noted that the residence time of the raw material palm oil in the evaporation surface of the short-path distillation apparatus (i.e., the processing time of the thin-film distillation) was set to a range of 5 seconds or more and 30 seconds or less.

[0146] The residual components (third residual component) and distillate components (third distillate component) were collected after short-path distillation under the above conditions.

[0147] [Table 1]

[0148]

[0149] (Preparation of blended oils)

[0150] 4000g of the first residual component and 8g of the third distillate component were mixed to obtain a mixed oil (equivalent to refined palm oil). The mixed oil was deodorized at 220°C for 80 minutes to obtain a deodorized mixed oil (which is also equivalent to refined palm oil).

[0151]

[0152] The composition of each sample (raw palm oil before short-path distillation, residual and distillate components obtained after each distillation process, and mixed oil) was studied as follows. The results are shown in Table 2.

[0153] (Quantitative analysis of total tocopherols)

[0154] According to the Japanese Oil Chemistry Association's "Standard Oil Analysis Test Method 2.4.10-2003 Tocopherol (Fluorescence Detector-High Performance Liquid Chromatography)," the total tocopherol (total amount of tocopherol isomers) content in each sample was determined.

[0155] (Quantification of total tocotrienols)

[0156] According to the Japanese Oil Chemists Association's "Standard Oil Analysis Test Method 2.4.10-2003 Tocopherols (Fluorescence Detector-High Performance Liquid Chromatography)," the total tocotrienol content (total amount of tocotrienol isomers) in each sample was determined.

[0157] (Quantitative analysis of diglycerides)

[0158] The content of diglycerides in each sample was determined based on AOCS “Official Method Cd 11b-91 Determination of Mono-and Diglycerides by Capillary Gas Chromatography”.

[0159] (Quantitative analysis of pure MCPD)

[0160] The quantification of 3-MCPD and 3-MCPD fatty acid esters in each refined oil was carried out in accordance with the modified method of the German official formulation law (DGF Standard Methods C-III 18(09)). The total amount of 3-MCPD (referred to as "pure MCPD") was converted into the total amount of 3-MCPD.

[0161] Specifically, 50 μL of internal standard (3-MCPD-d5 20 μg / mL solution) was added to 100 mg of each refined oil, followed by 1 mL of sodium methoxide solution (0.5 mol / L methanol). The reaction was carried out at room temperature for ester saponification. Then, 3 mL of sodium bromide aqueous solution (50%) containing trace amounts of acetic acid and 3 mL of hexane were added and mixed, and the hexane was removed. Subsequently, derivatives were obtained using 500 μL of phenylboronic acid aqueous solution (12.5%), extracted with 2 mL of hexane, and analyzed using gas chromatography-mass spectrometry.

[0162] The chromatograms obtained using the gas chromatography-mass spectrometry apparatus described above are compared with the ionic intensities of 3-MCPD-d5 and 3-MCPD, which serve as internal standards. The total amount of 3-MCPD and the fatty acid esters of 3-MCPD in the glycerol ester composition are then calculated using free 3-MCPD.

[0163] (Quantitative analysis of glycidol)

[0164] First, MCPD-FS was quantified using the following method.

[0165] [Quantitative analysis of MCPD-FS]

[0166] The total amount of 3-MCPD, glycidyl esters and their fatty acid esters in each refined oil was quantified according to the German official standard method (DGF Standard Methods C-III 18(09)). This total amount was referred to as "MCPD-FS".

[0167] Specifically, 50 μL of internal standard (3-MCPD-d5 20 μg / mL solution) was added to 100 mg of each refined oil, followed by 1 mL of sodium methoxide solution (0.5 mol / L methanol). The reaction was carried out at room temperature to saponify the esters. Then, 3 mL of saline solution (20%) containing trace amounts of acetic acid and 3 mL of hexane were added and mixed, and the hexane was removed. Subsequently, derivatives were derived using 250 μL of phenylboronic acid aqueous solution (25%), extracted with 2 mL of hexane, and analyzed using gas chromatography-mass spectrometry.

[0168] The chromatograms obtained using the gas chromatography-mass spectrometry apparatus described above are compared with the ionic strengths of 3-MCPD-d5 and 3-MCPD, which serve as internal standards. The total amount of 3-MCPD, glycidol, and their fatty acid esters in the oil is calculated by converting them to free 3-MCPD.

[0169] [Calculation of the amount of glycidyl ether]

[0170] Based on the MCPD-FS and pure MCPD values ​​specified by the above method, the amount of glycidol in each refined oil is calculated using the following formula (the total amount obtained by converting glycidol and its fatty acid esters into glycidol).

[0171] Glycerin content = (MCPD - FS - Pure MCPD) × 0.67

[0172] It should be noted that in the above formula, "0.67" refers to the value obtained by dividing the molecular weight of glycidyl (74.1) by the molecular weight of 3-MCPD (110.54).

[0173] [Table 2]

[0174]

[0175] As shown in Table 2, although the content of glycidol, 3-chloropropane-1,2-diol and their fatty acid esters was significantly lower in the blended oil and the deodorized blended oil (both equivalent to refined palm oils) compared to the raw palm oil, they still contained sufficient tocopherols.

[0176] <Study of the Properties of Matter>

[0177] The physical properties of each sample (raw palm oil before short-path distillation, first residual component, and mixed oil) were studied as follows. The results are shown in Table 3.

[0178] (Acid value)

[0179] Based on the "Standard Oil Analysis Test Method 2.3.1-2013 Acid Value" formulated by the Japan Oil Chemistry Society, the acid value of each sample was determined.

[0180] (Peroxide value (POV))

[0181] Based on the "Standard Oil Analysis Test Method 2.5.2.1-2013 Peroxide Value" formulated by the Japan Oil Chemistry Society, the peroxide value of each sample was determined.

[0182] (CDM value)

[0183] The test was conducted based on the "Standard Oil Analysis Test Method 2.5.1.2-2013 CDM Test" established by the Japan Oil Chemistry Society. It should be noted that the temperature of the constant temperature bath was 120°C.

[0184] (Storage test at 60℃)

[0185] Place 500g of each sample in a light-proof, sealed container and store at 60℃ (in the dark) for 2 weeks. Measure the flavor, acid value, peroxide value, and color after storage. The methods for determining acid value and peroxide value are as described above.

[0186] [Flavor Evaluation]

[0187] The flavor of RBD palm oil was used as a standard for evaluation using the following rating system.

[0188] 3: For the same flavor as RBD palm oil.

[0189] 2+: Slightly degraded compared to RBD palm oil.

[0190] 2: Compared to RBD palm oil, it feels inferior.

[0191] 1. Severely deteriorated, unsuitable for cooking oil.

[0192] [Color]

[0193] The Japanese Oil Chemistry Society has compiled "Test Method 2.2.1.1-2013 for the Analysis of Standard Oils and Fats - Color (Robibond Method)". It should be noted that the length of the liquid layer in the glass cuvette is 133.4 mm.

[0194] [Table 3]

[0195]

[0196] As shown in Table 3, blended oils and deodorized blended oils (both equivalent to refined oils (refined palm oils)) exhibited the same oxidative stability as the raw oils (raw palm oils).

Claims

1. A method for manufacturing refined oil, comprising the following steps: The first distillation step involves thin-film distillation of the raw oil under the first condition. The second distillation step involves subjecting the first distillate obtained after the first distillation step to thin-film distillation under second conditions. In the third distillation step, the second residual component obtained after the second distillation step is subjected to thin-film distillation under third conditions; and, The mixing process involves combining the first residual component obtained after the first distillation process with the third distillate component obtained after the third distillation process to obtain a mixed oil. The temperature under the first condition is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa. Compared to the first condition, the second and third conditions both have lower temperatures and lower vacuum levels (below 0.1 Pa). The temperature of the second condition is above 175°C, and compared with the third condition, the temperature of the second condition is at least 5°C lower and less than 15°C lower. The temperature of the third condition is below 195°C.

2. A method for manufacturing refined oil, comprising the following steps: The first distillation step involves thin-film distillation of the raw oil under the first condition. The third distillation step involves subjecting the first distillate obtained after the first distillation step to thin-film distillation under the third condition. In the second distillation step, the third distillate obtained after the third distillation step is subjected to thin-film distillation under the second conditions; and, The mixing process involves combining the first residual component obtained after the first distillation process with the second residual component obtained after the second distillation process to obtain a mixed oil. The temperature under the first condition is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa. Compared to the first condition, the second and third conditions both have lower temperatures and lower vacuum levels (below 0.1 Pa). The temperature of the second condition is above 175°C, and compared with the third condition, the temperature of the second condition is at least 5°C lower and less than 15°C lower. The temperature of the third condition is below 195°C.

3. The manufacturing method according to claim 1, wherein, The temperature of the second condition is above 175°C and below 185°C.

4. The manufacturing method according to claim 1, wherein, The temperature of the third condition is above 185°C and below 195°C.

5. The manufacturing method according to claim 1, wherein, The raw material oil is an oil that has undergone at least a deodorization process.

6. The manufacturing method according to claim 1, wherein, The raw material oil is palm oil.

7. The manufacturing method according to claim 1, wherein, The thin-film distillation process is a short-path distillation process.

8. A method for manufacturing tocopherols, comprising the following steps: The first distillation step involves thin-film distillation of the raw oil under the first condition. The second distillation step involves subjecting the first distillate obtained after the first distillation step to thin-film distillation under second conditions. In the third distillation step, the second residual component obtained after the second distillation step is subjected to thin-film distillation under third conditions; and, The recovery process involves recovering the third distillate obtained after the third distillation process. The temperature under the first condition is above 250°C and below 290°C, and the vacuum degree is below 0.1 Pa. Compared to the first condition, the second and third conditions both have lower temperatures and lower vacuum levels (below 0.1 Pa). The temperature of the second condition is above 175°C, and compared with the third condition, the temperature of the second condition is at least 5°C lower and less than 15°C lower. The temperature of the third condition is below 195°C.

9. A method for manufacturing tocopherols, comprising the following steps: The first distillation step involves thin-film distillation of the raw oil under the first condition. The third distillation step involves subjecting the first distillate obtained after the first distillation step to thin-film distillation under the third condition. In the second distillation step, the third distillate obtained after the third distillation step is subjected to thin-film distillation under the second conditions; and, The recovery process involves recovering the second residual component obtained after the second distillation process. The first condition is a temperature above 250°C and below 290°C, and a vacuum degree below 0.1 Pa. Compared to the first condition, the second and third conditions both have lower temperatures and lower vacuum levels (below 0.1 Pa). The temperature of the second condition is above 175°C, and compared with the third condition, the temperature of the second condition is at least 5°C lower and less than 15°C lower. The temperature of the third condition is below 195°C.

10. The manufacturing method according to claim 2, wherein, The temperature of the second condition is above 175°C and below 185°C.

11. The manufacturing method according to claim 2, wherein, The temperature of the third condition is above 185°C and below 195°C.

12. The manufacturing method according to claim 2, wherein, The raw material oil is an oil that has undergone at least a deodorization process.

13. The manufacturing method according to claim 2, wherein, The raw material oil is palm oil.

14. The manufacturing method according to claim 2, wherein, The thin-film distillation process is a short-path distillation process.

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