Method for producing edible oils and fats with reduced glycidol content

Abstract

Provided is a method for producing an edible oil / fat, the method making it possible to obtain an oil / fat having a good flavor and reduced glycidol content. Provided is a method for producing an edible oil / fat having a glycidol content of 1.5 mass ppm or less, the method including a continuous deodorization step that satisfies conditions (I) and (II) below. (I) Continuously performing the deodorization treatment for two times or more; and (II) the oil / fat temperatures in the deodorization treatments all being 200°C or higher, and the oil / fat temperature of an n+1-th deodorization treatment being lower by 10°C or more than the oil / fat temperature of the n-th deodorization treatment.

Description

[Technical Field]

[0001] The present invention relates to a method for producing edible oils and fats with reduced glycidol content. [Background technology]

[0002] For oils and fats intended for consumption, in order to improve the quality of the oils and fats, such as flavor and oxidative stability, crude oils extracted from plants and animals are subjected to refining processes that include degumming, deacidification, decolorization, and deodorization. Recently, RBD (Refined Bleached Deodorized) oils and fats refined by physical refining and NBD (Neutralized Bleached Deodorized) oils and fats refined by chemical refining have become available on the market. However, even with RBD and NBD oils, the refining is often insufficient from the standpoint of flavor and oxidative stability.

[0003] Therefore, in order to further improve the quality of oils and fats, as indicated by their flavor and oxidative stability, secondary refining is often performed on oils and fats that have already been refined, such as RBD oils and NBD oils.

[0004] In recent years, advances in analytical techniques have revealed that refined oils and fats, including RBD oils and NBD oils, contain glycidol and its fatty acid esters (hereinafter collectively referred to as "glycidols"). Glycidols are thought to be produced during the manufacturing process of edible oils and fats, for example, in the deodorization process, when the oils and fats are exposed to high temperatures. Glycidols are a cause for concern due to their potential adverse health effects, and various methods are being considered to reduce the glycidol content in oils and fats.

[0005] For example, research is underway on the deodorization process by steam distillation, which is commonly used when refining oils and fats. This includes methods for producing oils and fats by steam distillation of RBD oil under specific conditions (see Patent Document 1), methods for producing refined oils and fats characterized by contacting the oils and fats with an adsorbent and then steam distillation under specific conditions (see Patent Document 2), and methods for producing edible oils and fats using a combination of a thin-film column and a tray-type apparatus (see Patent Document 3). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-112761 [Patent Document 2] Japanese Patent Publication No. 2011-144343 [Patent Document 3] Japanese Patent Publication No. 2007-014263 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Previous methods for reducing the glycidol content had the problem of being difficult to achieve both a reduction in glycidol content and an improvement in the flavor and color of the oil itself.

[0008] In other words, when deodorization is performed at low temperatures, odor components cannot be sufficiently removed, which tends to spoil the flavor of the oils and fats. To avoid this, deodorization has traditionally been performed at high temperatures, but it has been found that while high temperatures can sufficiently remove odor components, they also produce glycidols as a by-product.

[0009] On the other hand, while deodorizing at low temperatures can suppress the formation of glycidols, it often results in insufficient improvement of the oil's flavor, making it unsuitable for consumption. This problem is particularly pronounced in palm oils, which are widely used as edible oils worldwide, and improvement has been sought.

[0010] Therefore, an object of the present invention is to provide a method for producing edible oil and fat that can obtain oil and fat with a reduced glycidol content and good flavor.

Means for Solving the Problems

[0011] As a result of intensive studies to solve the above problems, the present inventors have found that by subjecting raw material oil and fat to a deodorization step under specific temperature conditions during the production of edible oil and fat, edible oil and fat with reduced glycidols and good flavor can be obtained, and thus completed the present invention.

[0012] That is, the present invention relates to the following (1) to (7). (1) A method for producing edible oil and fat having a glycidol content of 1.5 mass ppm or less, including a continuous deodorization step that satisfies the following conditions (I) and (II). (I) The deodorization treatment is carried out continuously two or more times. (II) The oil and fat temperature in the deodorization treatment is 200°C or higher in each case, and the oil and fat temperature in the (n + 1)-th deodorization treatment is 10°C or lower than the oil and fat temperature in the n-th deodorization treatment. (2) The continuous deodorization step is A deodorization treatment α in which the oil and fat temperature is 250 to 280°C, the pressure is 3.0×10 Pa or less, the amount of blown steam is 0.8 to 6.0% by mass based on the oil, and the treatment time is 30 to 120 minutes, and A deodorization treatment β in which the oil and fat temperature is 200 to 240°C, the pressure is 3.0×10 2 Pa or less, the amount of blown steam is 0.8 to 6.0% by mass based on the oil, and the treatment time is 30 to 120 minutes The method according to (1), including. (3) The method according to (1) or (2), wherein the deodorization treatment in the continuous deodorization step consists only of the deodorization treatment using a tray-type device. (4) The method according to (3), wherein the tray-type device includes a total of two or more deodorization trays. (5) The method according to any one of (1) to (4), using a semi-continuous deodorization device. (6) The method according to any one of (1) to (5), wherein the raw material oil contains 50% by mass or more of palm oil. (7) A method for reducing the content of glycidols in oils and fats, comprising a continuous deodorization step that satisfies the following conditions (I) and (II). (I) Perform deodorization treatment two or more times consecutively. (II) The oil temperature in each deodorization treatment is 200°C or higher, and the oil temperature in the (n+1)th deodorization treatment is 10°C or lower than the oil temperature in the nth deodorization treatment. [Effects of the Invention]

[0013] According to the present invention's method for producing edible oils and fats, it is possible to obtain oils and fats with a sufficiently reduced glycidol content and good flavor. [Modes for carrying out the invention]

[0014] The present invention will be described in detail below with reference to its preferred embodiments. The present invention is not limited by the following description, and each component can be modified as appropriate without departing from the spirit of the invention.

[0015] [Method for producing edible oils and fats] The production of edible oils and fats, regardless of the origin of the oil, is usually carried out in the following order: degumming to remove phospholipids, deacidification to remove free fatty acids, decolorization to remove pigments, and deodorization to remove odor components. However, when RBD oil or NBD oil is used as the raw material, the degumming and deacidification steps are omitted, and only the decolorization and deodorization steps are performed. By going through these steps, it is possible to obtain edible oils and fats that are low in impurities, have a low acid value, are free of discoloration, and have no off-flavors.

[0016] The present invention's method for producing edible oils and fats (hereinafter also simply referred to as "the present invention's method") is characterized by including a continuous deodorization step that satisfies the following conditions (I) and (II) in place of the above-mentioned deodorization step. (I) Perform deodorization treatment two or more times consecutively. (II) The oil temperature in each deodorization treatment is 200°C or higher, and the oil temperature in the (n+1)th deodorization treatment is 10°C or lower than the oil temperature in the nth deodorization treatment.

[0017] <Condition (I)> First, let's discuss condition (I). In the continuous deodorization step of the manufacturing method of the present invention, the deodorization treatment is performed two or more times in succession.

[0018] In this invention, "performing deodorization treatment two or more times consecutively" means performing multiple deodorization treatments in succession, and specifically means performing the nth deodorization treatment and the (n+1)th deodorization treatment consecutively without going through any other steps between the nth deodorization treatment and the (n+1)th deodorization treatment. Other steps include, for example, degumming, deacidification, decolorization, and other steps commonly performed in the production of oils and fats, as well as steps involving contact with adsorbents such as silica gel, or with acids or alkalis. However, the step of appropriately adjusting the temperature of the oil or fat (including both raising and lowering the temperature) when transitioning from the nth deodorization treatment to the (n+1)th deodorization treatment is not included in the above-mentioned "other steps".

[0019] Furthermore, in the manufacturing method of the present invention, the deodorization treatment is considered as one treatment performed at a set constant oil temperature, regardless of the treatment time, and no operation is performed to change the oil temperature during that treatment. For example, even if the oil is deodorized at an oil temperature of 260°C, then cooled or heated to adjust the temperature, and then deodorized again at an oil temperature of 260°C, it will be treated as if two deodorization treatments have been performed. Naturally, even if the oil is deodorized at an oil temperature of 260°C, then cooled or heated to adjust the temperature, and then deodorized again at an oil temperature of 230°C, it will be treated as if two deodorization treatments have been performed.

[0020] In the continuous deodorization step of the manufacturing method of the present invention, the number of times the deodorization treatment is performed consecutively is not particularly limited as long as it is two or more times, and may be three, four or five times, or even more. From the viewpoint of efficiently obtaining edible oils and fats in which the glycidol content is sufficiently reduced and which have good flavor and color, from the viewpoint of performing the deodorization treatment while satisfying the conditions (II) described later, and from the viewpoint of production efficiency, the upper limit of the number of times the deodorization treatment is preferably five times or less, more preferably four times or less, or three times or less. In one particularly preferred embodiment, in the continuous deodorization step of the manufacturing method of the present invention, the deodorization treatment is performed twice consecutively.

[0021] In this invention, in relation to a series of deodorization treatments, the expressions "the nth deodorization treatment" and "the (n+1)th deodorization treatment" may be used. For example, if the number of consecutive deodorization treatments is 2, "the nth deodorization treatment" and "the (n+1)th deodorization treatment" represent the 1st and 2nd deodorization treatments, respectively. Also, if the number of consecutive deodorization treatments is 4, "the nth deodorization treatment" and "the (n+1)th deodorization treatment" may represent the 1st and 2nd deodorization treatments, the 2nd and 3rd deodorization treatments, or the 3rd and 4th deodorization treatments, respectively.

[0022] In the manufacturing method of the present invention, the deodorization treatment is not particularly limited in terms of conditions, as long as the conditions (II) described later are met, and can be carried out by conventional methods. For example, a deodorization treatment may be vacuum steam distillation, in which water vapor and oil are brought into contact under reduced pressure. Therefore, in one embodiment, in the continuous deodorization step of the manufacturing method of the present invention, the deodorization treatment by vacuum steam distillation is performed two or more times in succession.

[0023] When performing reduced-pressure steam distillation as a deodorization treatment, the steam and oil are brought into contact so that the oil temperature in each deodorization treatment is 200°C or higher, as described below.

[0024] The contact time (processing time) between water vapor and oil is preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more for each deodorization treatment. The upper limit of the processing time is preferably 150 minutes or less, more preferably 120 minutes or less, even more preferably 100 minutes or less, 80 minutes or less, or 60 minutes or less. Therefore, in one preferred embodiment, the processing time for each deodorization treatment is 30 to 120 minutes. When performing deodorization treatment using a tray-type device described later, each deodorization treatment may be performed using multiple deodorization trays set so that the oil temperatures are the same. For example, the nth deodorization treatment may be performed using two deodorization trays a and b (where the oil temperature in deodorization tray a and the oil temperature in deodorization tray b are the same), and the (n+1)th deodorization treatment may be performed using three deodorization trays c, d and e (where the oil temperature in deodorization tray c, the oil temperature in deodorization tray d, and the oil temperature in deodorization tray e are the same). In this case, the processing time for each deodorization treatment is set such that the sum of the deodorization times in each deodorization tray used in each deodorization treatment satisfies the above range. Specifically, the processing time for the nth deodorization treatment is the sum of the processing time ta in deodorization tray a and the processing time tb in deodorization tray b (ta+tb), and the processing time for the (n+1)th deodorization treatment is the sum of the processing time tc in deodorization tray c, the processing time td in deodorization tray d and the processing time te in deodorization tray e (tc+td+te), and it is preferable that each of these satisfies the above range.

[0025] The amount of blown-in steam, based on oil (when the oil and fat is 100% by mass), is preferably 0.5% by mass or more, more preferably 0.6% by mass or more, still more preferably 0.8% by mass or more, 1.0% by mass or more, or 1.2% by mass or more. The upper limit of the amount of blown-in steam, based on oil, is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, still more preferably 6.0% by mass or less, 5.0% by mass or less, 4.5% by mass or less, or 4.0% by mass or less. Therefore, in a preferred embodiment, the amount of blown-in steam in the deodorization treatment is 0.8 to 6.0% by mass. When performing the deodorization treatment using a tray-type device, as described above, the deodorization treatment may be performed using a plurality of deodorization trays set so that the oil and fat temperatures are the same for each time. In such a case, it is ensured that the sum of the amounts of blown-in steam in each deodorization tray used in each deodorization treatment satisfies the above range. For example, when performing the nth deodorization treatment using two deodorization trays a and b, and performing the (n + 1)th deodorization treatment using three deodorization trays c, d, and e, the amount of blown-in steam in the nth deodorization treatment is the sum (ma + mb) of the amount of blown-in steam ma in deodorization tray a and the amount of blown-in steam mb in deodorization tray b, and the amount of blown-in steam in the (n + 1)th deodorization treatment is the sum (mc + md + me) of the amount of blown-in steam mc in deodorization tray c, the amount of blown-in steam md in deodorization tray d, and the amount of blown-in steam me in deodorization tray e, and it is preferable that each of these satisfies the above range.

[0026] The reduced pressure condition is preferably 8.0×10 2 Pa or less, more preferably 5.0×10 2 Pa or less, still more preferably 3.0×10 2 Pa or less, 2.8×10 2 Pa or less, 2.5×10 2 Pa or less, 2.4×10 2 Pa or less, 2.2×10 2 Pa or less, or 2.0×10 2 Pa or less under reduced pressure.

[0027] The deodorization treatments performed in a continuous deodorization process may differ from one another to the other, or they may be the same, except for the temperature conditions.

[0028] <Condition (II)> Next, we will discuss condition (II). In the continuous deodorization step of the manufacturing method of the present invention, the oil temperature in each deodorization treatment is 200°C or higher, and the oil temperature in the (n+1)th deodorization treatment is 10°C or lower than the oil temperature in the nth deodorization treatment.

[0029] Regarding condition (II), "the oil temperature in all deodorization treatments is 200°C or higher" means that the oil temperature is 200°C or higher in any of the two or more consecutive deodorization treatments. For example, if the deodorization treatment is performed twice in a row, the oil temperature in both the first and second deodorization treatments must be 200°C or higher. If the deodorization treatment is performed four times in a row, the oil temperature must be 200°C or higher in all of the first, second, third, and fourth deodorization treatments.

[0030] By maintaining an oil temperature of 200°C or higher during the deodorization process, the edible oils obtained by the manufacturing method of the present invention have good flavor and color, and the acid value and peroxide value are sufficiently reduced. As a result, edible oils with higher oxidative stability can be obtained, as well as oils with reduced glycidol content. From the viewpoint of enjoying the effects of the present invention to the fullest, it is more preferable that the oil temperature during the deodorization process be 210°C or higher, and even more preferable that it be 215°C or higher.

[0031] While there are no specific upper limits on the oil temperature during the deodorization process, oils that have gone through a series of manufacturing steps are generally cooled to below 100°C before being removed from the system. Therefore, if the oil temperature is excessively high, cooling will take longer, which can easily reduce production efficiency. In addition, if the oil temperature is excessively high, the resulting edible oil will deteriorate more quickly over time.

[0032] Therefore, in the manufacturing method of the present invention, the upper limit of the oil temperature during the deodorization treatment is preferably 300°C or lower, more preferably 290°C or lower, even more preferably 280°C or lower, and even more preferably 270°C or lower.

[0033] Furthermore, in the continuous deodorization step of the manufacturing method of the present invention, the deodorization treatment is performed under conditions where the oil temperature of the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature of the nth deodorization treatment.

[0034] By performing the deodorization treatment under conditions where the oil temperature during the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature during the nth deodorization treatment, it is possible to achieve both a desirable flavor and color in the resulting edible oil and a reduction in the glycidol content in the edible oil.

[0035] From the viewpoint of enjoying the effects of the present invention, the difference in oil temperature between the nth and (n+1)th deodorization treatments is preferably 15°C or higher, more preferably 20°C or higher, even more preferably 25°C or higher, and even more preferably 30°C or higher.

[0036] The reason why the manufacturing method of the present invention, which includes a continuous deodorization step that satisfies condition (II), results in edible oils with a desirable flavor and reduced glycidol content is not yet clear, but the inventors believe it to be as follows.

[0037] Glycidols are known to be generated when oils and fats are exposed to high temperatures. Therefore, conventional methods for reducing glycidols have focused on not exposing oils and fats to high temperatures (especially above 200°C), and have aimed to reduce the amount of glycidols contained by applying various treatments (e.g., deodorization treatment and adsorbent treatment) while suppressing the generation of glycidols. The present invention's method for producing edible oils and fats has a completely different configuration from conventional methods. Specifically, in the production method of the present invention, the flavor of the oils and fats is sufficiently enhanced by performing the deodorization treatment n+1 times under conditions where the oil temperature is 200°C or higher, and by performing the deodorization treatment under conditions where the oil temperature of the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature of the nth deodorization treatment, it is presumed that in particular, in the (n+1)th deodorization treatment, the amount of glycidols reduced by the deodorization treatment exceeds the amount of glycidols generated, thus reducing the amount of glycidols contained in the final edible oils and fats. Furthermore, it is preferable not to add acids (organic acids or inorganic acids) or alkalis (organic bases or inorganic bases) to the oils and fats in the continuous deodorization process. For example, in the continuous deodorization process, the amount of organic acid (e.g., organic polycarboxylic acids such as citric acid and succinic acid) added to the oils and fats is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, even more preferably 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, 0.05% by mass or less, 0.01% by mass or less, or less than 0.01% by mass, relative to the oil (when the oils and fats are considered as 100% by mass), and may be 0% by mass.

[0038] <Condition (III)> In the manufacturing method of the present invention, the continuous deodorization step preferably satisfies the following condition (III) in addition to (I) and (II) above, from the viewpoint of achieving oils and fats that exhibit an even better flavor and have an even lower glycidol content. (III) Oil temperature 250-280°C, pressure 3.0 × 10 2 Deodorization treatment α is performed with a pressure of 0.8-6.0% by mass relative to the oil, and a processing time of 30-120 minutes, while the oil temperature is 200-240°C and the pressure is 3.0 × 10 2This includes a deodorization treatment β in which the pressure is Pa or less, the amount of water vapor injected is 0.8 to 6.0% by mass relative to the oil, and the treatment time is 30 to 120 minutes.

[0039] As described above, the manufacturing method of the present invention, by including a continuous deodorization step that satisfies conditions (I) and (II), can sufficiently improve the flavor, color, and stability of the oil and fat, and can also reduce the amount of glycidols contained in the final edible oil and fat. Furthermore, by including a continuous deodorization step that satisfies condition (III) above, the glycidol content can be further reduced, and it becomes easier to obtain oil and fat with an even better flavor.

[0040] Regarding condition (III), as long as deodorization treatment β is performed after deodorization treatment α, there is no prejudice to performing another deodorization treatment before deodorization treatment α, between deodorization treatment α and deodorization treatment β, or after deodorization treatment β.

[0041] From the viewpoint of obtaining edible oils and fats with even better flavor, the oil temperature for deodorization treatment α is more preferably 255°C or higher or 260°C or higher, and its upper limit is more preferably 275°C or lower or 270°C or lower. The pressure is more preferably 2.8 × 10⁻⁶ 2 It is less than or equal to Pa, and more preferably 2.5 × 10⁻⁶ 2 The pressure is less than or equal to Pa. The amount of steam blown in is more preferably 1.0% by mass or more, even more preferably 1.2% by mass or more, with an upper limit more preferably 5.5% by mass or less, even more preferably 4.5% by mass or less, and even more preferably 3.5% by mass or less. Therefore, in a preferred embodiment, the deodorization treatment α is performed at an oil temperature of 255-275°C and a pressure of 2.8 × 10⁻⁶ 2 Preferably, the process is carried out under conditions of Pa or less, a vapor injection rate of 1.0 to 4.5% by mass relative to the oil, and a processing time of 30 to 90 minutes, with an oil temperature of 255 to 270°C and a pressure of 2.5 × 10⁻⁶. 2 It is more preferable to carry out the process under conditions of Pa or less, a vapor injection rate of 1.2 to 3.5% by mass relative to the oil, and a processing time of 30 to 60 minutes.

[0042] Furthermore, from the viewpoint of obtaining edible oils and fats with good flavor and a further reduced glycidol content, the oil temperature for deodorization treatment β is more preferably 205°C or higher, even more preferably 210°C or higher, and even more preferably 215°C or higher, with an upper limit of more preferably 240°C or lower, even more preferably 235°C or lower, and even more preferably 230°C or lower. The pressure is more preferably 2.8 × 10⁻⁶ 2 It is less than or equal to Pa, and more preferably 2.5 × 10⁻⁶ 2 The pressure is less than or equal to Pa. The amount of water vapor injected is more preferably 1.0% by mass or more, even more preferably 1.2% by mass or more, with an upper limit more preferably 5.5% by mass or less, even more preferably 4.5% by mass or less, and even more preferably 3.5% by mass or less. Therefore, in a preferred embodiment, the deodorization treatment β is performed at an oil temperature of 205-235°C and a pressure of 2.8 × 10⁻⁶ 2 Preferably, the process is carried out under conditions of Pa or less, a vapor injection rate of 1.0 to 4.5% by mass relative to the oil, a processing time of 30 to 90 minutes, an oil temperature of 210 to 230°C (more preferably 215 to 230°C), and a pressure of 2.5 × 10⁻⁶. 2 It is more preferable to carry out the process under conditions of Pa or less, a vapor injection rate of 1.2 to 3.5% by mass relative to the oil, and a processing time of 30 to 60 minutes.

[0043] Furthermore, when performing deodorization treatments α and β using the tray-type device described later, deodorization treatment α may be performed using one deodorization tray or multiple deodorization trays. Similarly, deodorization treatment β may be performed using one deodorization tray or multiple deodorization trays. When performing each deodorization treatment using multiple deodorization trays, the treatment time and amount of steam blown in each deodorization treatment are the sum of the treatment time and amount of steam blown in each deodorization tray used in each deodorization treatment, as described above, and these values ​​are made to satisfy the above range.

[0044] In the continuous deodorization step of the manufacturing method of the present invention, if the number of consecutive deodorization treatments is two, it is preferable that the continuous deodorization step consists of the above-mentioned deodorization treatment α and deodorization treatment β.

[0045] <Regarding deodorization equipment used in continuous deodorization processes> Next, we will describe the deodorizing apparatus used in the continuous deodorization process in the manufacturing method of the present invention.

[0046] Generally, deodorizing devices are classified into Gardler type, Campro type, Campro-Miura type, gas lift pump type, column type, or combinations thereof, depending on their structure. Here, Gardler type, Campro type, Campro-Miura type, and gas lift pump type deodorizing devices will also be referred to as "tray type deodorizing devices" or "tray type devices" below. Deodorizing devices are also classified into batch type, semi-continuous type, continuous type, or combinations thereof, depending on the deodorizing method.

[0047] First, the structure of the deodorizing device preferably used in the continuous deodorization process in the manufacturing method of the present invention will be described.

[0048] In the continuous deodorization step of the manufacturing method of the present invention, any deodorizing device of any structure can be used as long as the deodorization treatment can be performed in a manner that satisfies the above conditions (I) and (II). In the manufacturing method of the present invention, the deodorization treatment is performed two or more times in succession, but the deodorizing device used for each deodorization treatment may be a single type of deodorizing device, or a combination of deodorizing devices of different structures may be used.

[0049] In the manufacturing method of the present invention, it is preferable to use only tray-type devices in each deodorization treatment. Therefore, in a preferred embodiment, the deodorization treatment in the continuous deodorization process consists solely of deodorization treatment using tray-type devices. Particularly from the viewpoint of manufacturing efficiency, it is preferable to use only Campro type, Campro-Miura type, or gas lift pump type tray-type devices. Column-type deodorizers are effective when deodorizing large quantities of a single type of oil, but in the present invention, it is necessary to perform the deodorization treatment two or more times in succession while changing the temperature, and when a column-type deodorizer is used, the manufacturing efficiency of edible oil tends to deteriorate.

[0050] Note that the Campro type, Campro Miura type, or gas lift pump type may be collectively referred to as "gas lift pump type, etc."

[0051] A Gardler-type deodorizer has a structure in which trays are installed inside a cylindrical vacuum tower (also called a shell) that stands perpendicular to the direction of gravity. These trays include a preheating tray, a heating tray, one or more deodorizing trays, a heat recovery tray, a cooling tray, etc. The oil and grease introduced into the deodorizer are heated in the preheating tray and heating tray, and then heated under reduced pressure in the deodorizing trays to deodorize them.

[0052] The Campro and Campro-Miura type deodorizers are equipped with multiple pairs of plates (hereinafter also simply referred to as "deodorizing plates") that are positioned parallel to each other within the deodorizing tray, and a steam injection pipe is provided at the lower end of each plate. Both the Campro and Campro-Miura type deodorizers, like the Gardler type, have a preheating tray, a heating tray, one or more deodorizing trays, a heat recovery tray, and a cooling tray.

[0053] A gas lift pump type deodorizer has a structure in which one or more long cylinders are provided in the deodorizing tray so as to penetrate the oil surface from within the oil, a umbrella-shaped cover is provided with a small space above the upper end of the cylinder, and a steam injection pipe is provided at the lower end of the cylinder. Similar to the Gardler type, the gas lift pump type deodorizer also has a preheating tray, a heating tray, one or more deodorizing trays, a heat recovery tray, and a cooling tray.

[0054] In the Campro and Campro-Miura tray-type devices, the lower end of the deodorizing plate in the deodorizing tray is immersed in the oil to be refined, and steam is blown in while heating under reduced pressure. As a result, the oil spreads along with the steam on the surface of the deodorizing plate, forming a thin film on that surface, while the oil is ejected from the upper end of the deodorizing plate. Thus, the oil is deodorized by forming a thin film on the deodorizing plate and by ejecting the oil under high temperature and reduced pressure.

[0055] In a gas-lift pump type tray system, the lower end of a cylinder in the deodorizing tray is immersed in the oil to be refined, and steam is blown in while heating under reduced pressure. As a result, the oil rises inside the cylinder along with the steam, and is ejected from the upper end of the cylinder. The oil then collides with a umbrella-shaped cover provided at the upper end of the cylinder, forming a thin film of oil, and the oil is deodorized by being ejected under high temperature and reduced pressure.

[0056] A column-type deodorizer is a deodorizer that uses a thin-film column equipped with a packing material.

[0057] As described above, tray-type devices have multiple trays within their structure, and in most tray-type devices, one or more of these trays are typically designated as deodorizing trays.

[0058] The number of deodorizing trays can usually be set arbitrarily according to the number of trays in each tray-type device, but in the manufacturing method of the present invention, the tray-type device used to carry out the continuous deodorization process preferably includes a total of two or more deodorizing trays, more preferably three or more deodorizing trays, and even more preferably four or more deodorizing trays. There is no particular upper limit to the number of deodorizing trays in the tray-type device, but it can usually be 10 or less, 8 or less, 6 or less, etc.

[0059] In the manufacturing method of the present invention, the continuous deodorization process may be carried out by performing each deodorization treatment using a separate deodorization device. For example, the continuous deodorization process may be carried out by performing the first deodorization treatment using a first deodorization device and the second and subsequent deodorization treatments using a second deodorization device. From the viewpoint of the manufacturing efficiency of oils and fats, it is preferable to carry out the continuous deodorization process using a single tray-type device. More specifically, it is preferable to carry out the continuous deodorization process using a tray-type device having multiple deodorization trays, assigning one or more deodorization trays to each deodorization treatment. For example, it is possible to use a tray-type device having four deodorization trays, perform the first deodorization treatment using two deodorization trays, and perform the second deodorization treatment using the other two deodorization trays.

[0060] In the manufacturing method of the present invention, when a continuous deodorization process is carried out using a single tray-type device, the upper limit of the number of deodorization trays allocated to each deodorization treatment is usually four trays or less.

[0061] When manufacturing edible oils and fats using the manufacturing method of the present invention with a tray-type apparatus, the order of the heating tray, deodorizing tray, heat recovery tray, and cooling tray within the tray-type apparatus, as well as the number of each tray allocated, can be arbitrarily set depending on the scale of edible oil and fat production, the scale of the tray-type apparatus, and the number of trays within the tray-type apparatus.

[0062] For example, when using a tray-type apparatus with 10 trays to perform deodorization twice in a row, specifically when performing a continuous deodorization process including the above deodorization processes α and β, the oil and grease may be heated to a predetermined temperature using trays 1 and 2 as heating trays, deodorization process α may be performed using trays 3 and 4 as deodorization trays, the oil and grease may be heated to a predetermined temperature using trays 5 and 6 as heating or cooling trays, deodorization process β may be performed using trays 7 and 8 as deodorization trays, and the oil and grease may be cooled to approximately 100°C or below using trays 9 and 10 as cooling trays. The cooled oil and grease may be removed from the continuous deodorization process system (outside the deodorization apparatus system).

[0063] Next, we will describe the deodorization method of the deodorization apparatus preferably used in the continuous deodorization process in the manufacturing method of the present invention.

[0064] In the continuous deodorization step of the manufacturing method of the present invention, any deodorizing device of any type can be used as long as the deodorization treatment can be performed in a manner that satisfies the above conditions (I) and (II). In the manufacturing method of the present invention, the deodorization treatment is performed two or more times in succession, but the deodorizing device used for each deodorization treatment may be a single type of deodorizing device, or a combination of deodorizing devices of different deodorizing types may be used. As mentioned above, depending on the deodorization method, there are batch-type, semi-continuous-type, continuous-type, or combinations thereof of deodorizing devices, and any type of deodorizing device may be used for each deodorization treatment.

[0065] Here, a semi-continuous deodorizing device has a control valve in each tray and a structure that prevents oils and greases from mixing between trays, while a continuous deodorizing device does not have control valves, all the trays are connected, and oils and greases are continuously supplied into the deodorizing device.

[0066] In the present invention, it is preferable to use a semi-continuous, continuous, or combination thereof deodorizing device for each deodorizing treatment, and it is particularly preferable to use a semi-continuous deodorizing device.

[0067] In the manufacturing method of the present invention, the deodorization process is performed two or more times in succession. However, when using a batch-type deodorization device, transitions from other manufacturing processes to the deodorization process, or transitions between deodorization processes, tend to be inefficient from a manufacturing perspective.

[0068] Furthermore, when using a continuous deodorizing device, oil and grease are continuously supplied into the device, making it difficult to adjust the oil and grease temperature in each deodorization treatment in the continuous deodorization process of the present invention. Consequently, the effect of the present invention, which is to reduce glycidols, may not be fully achieved. When using a semi-continuous deodorizing device, it is preferable because it is easier to adjust the oil and grease temperature to a predetermined value in each deodorization treatment in the continuous deodorization process, and it is easier to achieve oil and grease with even less glycidols.

[0069] <Regarding other manufacturing processes> As mentioned above, the production of edible oils and fats is usually carried out in the following order: degumming to remove phospholipids, deacidification to remove free fatty acids, decolorization to remove pigments, and deodorization to remove odor components. Furthermore, when RBD oils or NBD oils are used as raw materials, the degumming and deacidification steps are omitted, and only the decolorization and deodorization steps are performed.

[0070] The manufacturing method of the present invention is characterized by including a continuous deodorization step that satisfies the above conditions (I) and (II), preferably (I) to (III), instead of the above deodorization step, and the other degumming, deacidification, and decolorization steps are carried out by conventional methods. Therefore, the manufacturing method of the present invention may include a degumming step, a deacidification step, and a decolorization step in addition to the above continuous deodorization step. When RBD oil or NBD oil is used as the raw material oil, the manufacturing method of the present invention may include a decolorization step in addition to the above continuous deodorization step.

[0071] <About raw oils and fats> The method for producing edible oils and fats of the present invention can be applied to any edible oil or fat without particular limitations.

[0072] Edible oils and fats to which the manufacturing method of the present invention can be applied include, for example, 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; animal oils such as beef tallow, milk fat, lard, fish oil, and whale oil; and processed oils and fats obtained by subjecting these oils and fats to one or more treatments selected from hydrogenation, fractionation, and transesterification. The present invention may be applied to a single edible oil or fat selected from these, or to a mixture of two or more edible oils and fats.

[0073] Furthermore, the manufacturing method of the present invention may be applied to crude oil or to already refined oils and fats. Glycidols are known to be produced when oils and fats are exposed to high temperatures during the manufacturing process, and it is preferable to apply the manufacturing method of the present invention to oils and fats that have undergone one or more deodorization steps by steam distillation at high temperatures. Therefore, in a preferred embodiment, the manufacturing method of edible oils and fats of the present invention is performed on oils and fats that have undergone one or more deodorization steps. The deodorization steps may be carried out by conventional methods. In particular, it is preferable to select RBD oils and fats that have been primary refined by physical refining of crude oil, or NBD oils and fats that have been primary refined by chemical refining of crude oil.

[0074] The manufacturing method of the present invention is particularly effective and therefore preferably applied to edible oils containing palm oils. In the present invention, palm oils refer to palm kernel oil; lauric palm oil obtained by subjecting oils containing palm kernel oil to one or more physical or chemical treatments selected from hydrogenation, fractionation, and transesterification; palm oil; and non-lauric palm oil obtained by subjecting oils containing palm oil to one or more physical or chemical treatments selected from hydrogenation, fractionation, and transesterification. Regardless of which palm oil is included, the manufacturing method of the present invention makes it possible to produce oils with an extremely low glycidol content.

[0075] The content of palm-based oils in the raw oils to which the manufacturing method of the present invention is applied is not particularly limited and is arbitrary, but from the viewpoint of obtaining the effects of the present invention significantly, it is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more or 95% by mass or more.

[0076] In particular, from the viewpoint of significantly enjoying the effects of the present invention, the glycidol content in the raw oil to which the manufacturing method of the present invention is applied is preferably 15 ppm by mass or less, more preferably 10 ppm by mass or less, even more preferably 7 ppm by mass or less, and even more preferably 5 ppm by mass or less or 4 ppm by mass or less. The lower limit of the glycidol content in the raw oil is not particularly limited and may be 0 ppm by mass.

[0077] <Characteristics of oils and fats obtained by the manufacturing method of the present invention> The edible oils and fats obtained by the manufacturing method of the present invention have a good flavor while being characterized by an extremely low glycidol content.

[0078] For example, although it varies depending on the grade as defined by DOBI, etc., when the manufacturing method of the present invention is applied to RBD palm oils with a glycidol content of more than 3 ppm by mass, the total glycidol content in the resulting edible oil will be 1.5 ppm by mass or less, preferably 1.2 ppm by mass or less, more preferably 1 ppm by mass or less, even more preferably less than 1 ppm by mass, 0.9 ppm by mass or less, 0.8 ppm by mass or less, 0.7 ppm by mass or less, 0.6 ppm by mass or less, or 0.5 ppm by mass or less. The lower limit of the total glycidol content in the resulting edible oil is not particularly limited and can be 0 ppm by mass.

[0079] There are two main methods for quantifying the glycidol content in oils and fats: direct analysis and indirect analysis, based on fundamental differences in principle. In this invention, either method may be used for quantification, but it is preferable to quantify glycidols using indirect analysis because it requires fewer types of standard substances and is more economical. For example, a simple indirect analysis method can be used, as described in Japanese Patent Publication No. 5864278 or in Oleoscience Vol. 17 No. 4 (2017) pp. 171-178. This method involves hydrolyzing glycidyl fatty acid esters in oils and fats to convert them into free components, derivatizing these with phenylboric acid, and then measuring them by GC-MS. The measurement conditions by GC-MS can be arbitrarily set with reference to the above-mentioned literature, but for example, measurements can be performed under the following conditions.

[0080] [Gas Chromatography Department] • Column: VF-5ms ·Injection volume: 1uL • Injection method: Splitless ·Inlet temperature: 250℃ Carrier gas: Helium, 1.2 mL / min Column oven: 60℃: 1 minute → 60~150℃: 10℃ / min, 150~180℃: 3℃ / min, 180~300℃: 30℃ / min, 300℃: 8 minutes. Total: 32 minutes.

[0081] [Mass Spectrometry Department] Transfer line: 280℃ Ion source temperature: 230℃ ·Quadrupole temperature: 150℃ Ionization method: EI, positive ion

[0082] <Foods using edible oils and fats obtained by the manufacturing method of the present invention> The edible oils and fats obtained by the manufacturing method of the present invention can be used in the manufacture of food and beverages, just like ordinary oils and fats. Food and beverages using the edible oils and fats obtained by the manufacturing method of the present invention have the characteristic of having a lower glycidol content than food and beverages using conventional oils and fats.

[0083] Examples of the above-mentioned foods and beverages include processed foods such as margarine, shortening, fat spreads, dressings, mayonnaise, frozen desserts, spray oils, frying oils, chocolate oils, batter oils, and powdered oils, as well as ingredients for confectionery and bread making such as flower paste and bean paste, Western-style sweets, Japanese-style sweets, bread, snacks, curry, stew, gratin, seasonings, instant prepared foods, processed livestock products, processed seafood products, and processed vegetables. It can also be used as an ingredient in foods and beverages that require a high degree of glycidol reduction, such as infant formula for infants.

[0084] [Method for reducing the glycidol content in oils and fats] The present invention also provides a method for reducing the content of glycidols in oils and fats (hereinafter also simply referred to as "the reduction method of the present invention").

[0085] The present invention's reduction method is characterized by including a continuous deodorization step that satisfies the following conditions (I) and (II). (I) Perform deodorization treatment two or more times consecutively. (II) The oil temperature in each deodorization treatment is 200°C or higher, and the oil temperature in the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature in the nth deodorization treatment.

[0086] Details and preferred ranges of conditions (I) and (II) are as described in the above [Method for producing edible oils and fats].

[0087] The target oils to which the reduction method of the present invention can be applied are the same as those described as raw oils in the above [Method for producing edible oils]. By applying the reduction method of the present invention, the glycidol content in oils can be reduced to 1.5 ppm by mass or less, preferably 1.2 ppm by mass or less, more preferably 1 ppm by mass or less, even more preferably less than 1 ppm by mass, 0.9 ppm by mass or less, 0.8 ppm by mass or less, 0.7 ppm by mass or less, 0.6 ppm by mass or less, or 0.5 ppm by mass or less.

[0088] In the continuous deodorization step of the reduction method of the present invention, the number of times the deodorization treatment is performed consecutively is not particularly limited as long as it is two or more times, and may be three, four or five times, or even more. From the viewpoint of efficiently obtaining edible oils and fats in which the glycidol content is sufficiently reduced and which have good flavor and color, and from the viewpoint of not reducing production efficiency, the upper limit of the number of times the deodorization treatment is preferably five times or less, more preferably four times or less, or three times or less. In one particularly preferred embodiment, in the continuous deodorization step of the reduction method of the present invention, the deodorization treatment is performed twice consecutively.

[0089] In the reduction method of the present invention, from the viewpoint of realizing oils and fats that exhibit an even better flavor and have an even lower glycidol content, it is preferable that the continuous deodorization step satisfies the following condition (III) in addition to (I) and (II) above. (III) Oil temperature 250-280°C, pressure 3.0 × 10 2 Deodorization treatment α is performed with a pressure of 0.8-6.0% by mass relative to the oil, and a processing time of 30-120 minutes, while the oil temperature is 200-240°C and the pressure is 3.0 × 10 2 This includes a deodorization treatment β in which the pressure is Pa or less, the amount of water vapor injected is 0.8 to 6.0% by mass relative to the oil, and the treatment time is 30 to 120 minutes.

[0090] The details and preferred range of condition (III) are as described in the above [Method for Manufacturing Edible Oils and Fats], and as long as deodorization treatment β is performed after deodorization treatment α, there is no prejudice to performing another deodorization treatment before deodorization treatment α, between deodorization treatment α and deodorization treatment β, or after deodorization treatment β.

[0091] When the deodorization treatment is performed consecutively twice, it is preferable that the consecutive deodorization step in the reduction method of the present invention consists of deodorization treatment α and deodorization treatment β. [Examples]

[0092] The present invention will be described in further detail below based on examples. However, the present invention is not limited to the examples shown below.

[0093] [Measurement and Evaluation Methods] This section explains the measurement and evaluation methods.

[0094] In the following examples and comparative examples, deodorization was performed using a semi-continuous tray-type apparatus. The semi-continuous tray-type apparatus used was a gas-lift pump type, etc., and had 10 trays inside. In the examples and comparative examples where a continuous deodorization process was performed, the trays were assigned in the order in which the oil flowed in: trays 1 and 2 were used as heating trays to heat the oil to a predetermined temperature; trays 3 and 4 were used as deodorization trays for deodorization; trays 5 and 6 were used as temperature-controlled trays to heat or cool the oil to a predetermined temperature; trays 7 and 8 were used as deodorization trays for deodorization; and trays 9 and 10 were used as cooling trays to cool the oil to 90°C or below. The cooled oil was removed from the tray-type apparatus system. In comparative examples 1-1 and 1-2, where deodorization was performed only once, the trays were assigned in the same manner as above, except that the oil passed through trays 7 and 8 while being temperature-controlled to maintain the oil temperature (no deodorization was performed in trays 7 and 8). In Comparative Example 1-3, which involved a step of contacting the oil with an adsorbent between two deodorization treatments, each tray was assigned in the same manner as in Comparative Examples 1-1 and 1-2. In Comparative Example 1-3, the first deodorization treatment was performed using the tray-type apparatus, the extracted oil was subjected to a step of contacting the adsorbent, and then the second deodorization treatment was performed again using the tray-type apparatus.

[0095] <Measurement of glycidol content in oils and fats> The glycidol content in the oils and fats was measured using an indirect analytical method following the procedure below.

[0096] The refined oils and fats obtained in the examples and comparative examples were hydrolyzed to convert the fatty acid ester of glycidol to the free component glycidol according to the method described in [Examples] of Japanese Patent No. 5864278. These were then derivatized with phenylboric acid and quantified using GC-MS. The conditions for the gas chromatography (GC) and mass spectrometry (MS) sections were as follows.

[0097] -Gas Chromatography Department- • Column: VF-5ms ·Injection volume: 1uL • Injection method: Splitless ·Inlet temperature: 250℃ Carrier gas: Helium, 1.2 mL / min Column oven: 60℃: 1 minute → 60~150℃: 10℃ / min, 150~180℃: 3℃ / min, 180~300℃: 30℃ / min, 300℃: 8 minutes. Total: 32 minutes. -Mass Spectrometry Department- Transfer line: 280℃ Ion source temperature: 230℃ ·Quadrupole temperature: 150℃ Ionization method: EI, positive ion

[0098] <Evaluation of the flavor of oils and fats> The day after production, 2g of oil, heated to 60°C, was measured out using a teaspoon and tasted directly by 12 panelists. They evaluated whether or not they detected any off-flavors according to the evaluation criteria shown below. Prior to the flavor evaluation, the panelists' sensory perception levels were coordinated. The average scores of the 12 panelists were shown in Table 1 as follows: -- when 8.0-8.3 points, - when 8.4-8.7 points, ± when 8.8-9.1 points, + when 9.2-9.4 points, and ++ when 9.5 points or higher.

[0099] Evaluation criteria: 10 points: No unpleasant taste when put in the mouth. 9 points: You feel an unpleasant taste 2-3 seconds after putting it in your mouth. 8 points: I felt an unpleasant taste immediately after putting it in my mouth.

[0100] [Consideration 1: Regarding the effectiveness of the continuous deodorization process] To RBD palm olein (manufactured by Wilmer, glycidol content 5.89 ppm by mass), 2% by mass of white clay was added relative to the weight of the oil, resulting in 1.0 × 10⁻⁶ 3 The decolorization treatment was performed by stirring for 45 minutes under reduced pressure below Pa, while maintaining the oil temperature at 85°C.

[0101] The decolorized palm olein obtained was subjected to deodorization treatment under the deodorization conditions shown in Comparative Examples 1-1 to 1-3 and Example 1-1, and then examined. The decolorized palm olein used in Comparative Examples 1-1 to 1-3 and Example 1-1 was from the same manufacturing lot. The glycidol content in this decolorized palm olein was 0.04 ppm by mass, and its flavor was evaluated according to the above criteria, resulting in a rating of "--".

[0102] (Comparative Example 1-1) Dissolve the decolorized palm olein and 3.0 × 10 2 The oil was subjected to reduced-pressure steam distillation at 260°C for 40 minutes under a reduced pressure of less than Pa. In this way, edible oil that had undergone only one deodorization treatment under general conditions was obtained. The amount of steam blown in was 3% by mass / h relative to the oil.

[0103] (Comparative Example 1-2) Dissolve the decolorized palm olein and 3.0 × 10 2 The oil was subjected to reduced-pressure steam distillation at 230°C for 40 minutes under a reduced pressure of less than Pa. This yielded edible oil that had undergone only one deodorization treatment at a lower temperature than typical conditions. The amount of steam injected was 3% by mass / h relative to the oil.

[0104] (Comparative Examples 1-3) Dissolve the decolorized palm olein and 3.0 × 10 2 The oil was subjected to reduced pressure (below Pa) and subjected to vacuum steam distillation at 260°C for 40 minutes. After contacting the extracted oil with an adsorbent (activated clay) at a concentration of 0.5% by mass relative to the oil, it was further subjected to 3.0 × 10⁻⁶ 2 Edible oil was obtained by vacuum steam distillation at 210°C for 40 minutes under reduced pressure of less than Pa. The amount of steam blown in was 3% by mass / h relative to the oil.

[0105] (Example 1-1) Dissolve the decolorized palm olein and 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2The oil was subjected to reduced-pressure steam distillation at 210°C for 40 minutes under a pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 3% by mass / h relative to the oil.

[0106] In the following, the edible oils and fats of Comparative Examples 1-1 to 1-3 may be referred to as CEx1-1 to CEx1-3, and the edible oil and fat of Example 1-1 as Ex1-, corresponding to the numbers of the Examples and Comparative Examples. The same may be applied to subsequent Examples and Comparative Examples.

[0107] Table 1 shows the evaluation results for CEx1-1 to CEx1-3 and Ex1-1. In this study, only those that received a + or ++ rating for flavor were considered to have passed.

[0108] [Table 1]

[0109] [Consideration 2: Various conditions for deodorization treatment in the continuous deodorization process] Random transesterification oil (hereinafter also simply referred to as "RIE-PSO") obtained by random transesterification of palm superolein (iodine value 65, manufactured by Kecksang, glycidol content 7.75 ppm by mass) using a conventional method was subjected to decolorization treatment in the same manner as in Study 1 to obtain decolorized RIE-PSO.

[0110] The obtained decolorized RIE-PSO was subjected to deodorization treatment under the deodorization conditions shown in Comparative Examples 2-1, 2-2, and Examples 2-1 to 2-4, and then examined. In Study 2, since the manufacturing lots of the decolorized RIE-PSO used may differ, the glycidol content in the decolorized RIE-PSO used is shown in Table 2.

[0111] (Comparative Example 2-1) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 265°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed at 3.0 × 10 2The oil was subjected to reduced-pressure steam distillation at 180°C for 40 minutes under a pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 1.2% by mass / h relative to the oil.

[0112] (Comparative Example 2-2) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2 The oil was subjected to reduced-pressure steam distillation at 255°C for 40 minutes under a reduced pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 1.2% by mass / h relative to the oil.

[0113] (Example 2-1) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2 The oil was subjected to reduced-pressure steam distillation at 210°C for 40 minutes under a pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 1.2% by mass / h relative to the oil.

[0114] (Example 2-2) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2 The oil was subjected to reduced-pressure steam distillation at 220°C for 40 minutes under a pressure of less than Pa. This resulted in a continuous deodorization process involving two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 1.2% by mass / h relative to the oil.

[0115] (Example 2-2-2) Except for setting the amount of water vapor injected to 1.9% by mass / h relative to the oil, the deodorization process was carried out twice in a row in the same manner as in Example 2-2 to obtain edible oil.

[0116] (Examples 2-3) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2 The oil was subjected to reduced-pressure steam distillation at 230°C for 40 minutes under a pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 3% by mass / h relative to the oil.

[0117] (Examples 2-4) Dissolve the decolorized RIE-PSO and add 3.0 × 10 2 After being subjected to reduced pressure steam distillation at 260°C for 40 minutes under a pressure of less than Pa, it is transferred to another deodorizing tray and further processed in 3.0 × 10⁻⁶ units. 2 The oil was subjected to reduced-pressure steam distillation at 245°C for 40 minutes under a reduced pressure of less than Pa. This process involved two consecutive deodorization treatments to obtain edible oil. The amount of steam injected was 3% by mass / h relative to the oil.

[0118] Table 2 shows the evaluation results for CEx2-1, CEx2-2, and Ex2-1 to Ex2-4. In this study, only those that received a + or ++ rating for flavor were considered to have passed.

[0119] [Table 2]

Claims

1. A method for producing edible oils and fats having a glycidol content of 1.5 ppm by mass or less, comprising a continuous deodorization step that satisfies the following conditions (I) and (II), wherein the step comprises a deodorization step α in which the oil temperature is 250 to 280°C, the pressure is 3.0 × 10² Pa or less, the amount of steam blown in is 0.8 to 6.0% by mass relative to the oil, and the processing time is 30 to 120 minutes, and a deodorization step β in which the oil temperature is 200 to 240°C, the pressure is 3.0 × 10² Pa or less, the amount of steam blown in is 0.8 to 6.0% by mass relative to the oil, and the processing time is 30 to 120 minutes. (I) Perform the deodorization treatment two or more times consecutively. (II) The oil temperature in each deodorization treatment is between 200°C and 280°C, and the oil temperature in the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature in the nth deodorization treatment.

2. The method according to claim 1, wherein the deodorization process in the continuous deodorization process consists solely of a deodorization process using a tray-type device.

3. The method according to claim 2, wherein the tray-type device includes a total of two or more deodorizing trays.

4. The method according to any one of claims 1 to 3, wherein a semi-continuous deodorizing device is used.

5. The method according to any one of claims 1 to 4, wherein the raw material oil contains 50% by mass or more of palm oil.

6. A method for reducing the glycidol content in oils and fats, comprising a continuous deodorization step that satisfies the following conditions (I) and (II), wherein the step includes a deodorization treatment α in which the oil temperature is 250 to 280°C, the pressure is 3.0 × 10² Pa or less, the amount of steam blown in is 0.8 to 6.0 mass% relative to the oil, and the treatment time is 30 to 120 minutes, and a deodorization treatment β in which the oil temperature is 200 to 240°C, the pressure is 3.0 × 10² Pa or less, the amount of steam blown in is 0.8 to 6.0 mass% relative to the oil, and the treatment time is 30 to 120 minutes. (I) Perform the deodorization treatment two or more times consecutively. (II) The oil temperature in each deodorization treatment is between 200°C and 280°C, and the oil temperature in the (n+1)th deodorization treatment is 10°C or more lower than the oil temperature in the nth deodorization treatment.

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