Production method of oil and fat and method of inhibiting discoloration of oil and fat

Abstract

To provide a production method of oil and fat and a method of inhibiting discoloration of oil and fat which can inhibit discoloration of oil and fat during the storage in the case that diatom earth is used as a filtration auxiliary in a filtering process to produce the oil and fat.SOLUTION: In a production method of oil and fat which includes a filtering process of filtering oil and fat to be refined by using diatom earth as a filtration auxiliary, one or more processes chosen from the following processes A to C or a process D is included. Process A: a process of treating the oil and fat to be refined with solid organic acid at 8 ppm or more with respect to the oil and fat to be refined after the filtering process. Process B: a process of treating the oil and fat to be refined with organic acid at 8 ppm or more with respect to the oil and fat to be refined before the filtering process. Process C: a process of water-washing the oil and fat to be refined with water in 10 times by mass or more of the diatom earth after the filtering process. Process D: a process of water-washing the oil and fat to be refined with water in 2 times by mass or more of the diatom earth after the process of treating the oil and fat to be refined with organic acid at 5 ppm or more with respect to the oil and fat to be refined after the filtering process.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In the process of producing fats and oils, there is a filtration process, and a filter aid may be used in the filtration process. As the filter aid, for example, diatomaceous earth is known (Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when diatomaceous earth is used as a filter aid in the filtration process of fats and oils, there is a problem that the produced fats and oils are colored orange during storage.

[0005] Therefore, an object of the present invention is to provide a method for producing fats and oils and a method for suppressing coloring of fats and oils that can suppress the coloring of fats and oils during storage when fats and oils are produced using diatomaceous earth as a filter aid in the filtration process.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention provides the following method for producing fats and oils and method for suppressing coloring of fats and oils.

[0007] In addition, in the present invention, the description of X (numerical value) to Y (numerical value) means X or more and Y or less unless otherwise specified.

[0008] [1] A method for producing oils and fats, comprising a filtration step of filtering oils and fats to be refined using diatomaceous earth as a filter aid, comprising one or more steps selected from the following steps A to C, or step D. Step A: A step following the filtration step, in which the oil to be refined is treated with a solid organic acid at a concentration of 8 ppm or higher. Step B: A step in which the oil to be refined is treated with an organic acid at a concentration of 8 ppm or higher, prior to the filtration step. Step C: A step in which, after the filtration step, the oil to be refined is washed with water at least 10 times the mass of the diatomaceous earth. Step D: A step following the filtration step, in which the oil to be refined is treated with an organic acid at a concentration of 5 ppm or more, and then the oil to be refined is washed with water at a concentration of at least twice the mass of the diatomaceous earth. [2] A method for producing oils and fats according to [1], comprising step A. [3] A method for producing oils and fats according to [1] or [2], comprising step B. [4] A method for producing oils and fats according to any one of [1] to [3], comprising step C. [5] A method for producing oil and fat according to [1], comprising step A or step B, and step C performed after step A or step B. [6] A method for producing oil and fat according to [1], comprising step D. [7] A method for suppressing the discoloration of oils and fats, comprising a filtration step of filtering oils and fats to be refined using diatomaceous earth as a filter aid, wherein the method comprises one or more steps selected from the following steps A to C, or step D. Step A: A step following the filtration step, in which the oil to be refined is treated with a solid organic acid at a concentration of 8 ppm or higher. Step B: A step in which the oil to be refined is treated with an organic acid at a concentration of 8 ppm or higher, prior to the filtration step. Step C: A step in which, after the filtration step, the oil to be refined is washed with water at least 10 times the mass of the diatomaceous earth. Step D: A step following the filtration step, in which the oil to be refined is treated with an organic acid at a concentration of 5 ppm or more, and then the oil to be refined is washed with water at a concentration of at least twice the mass of the diatomaceous earth. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing oils and fats and a method for suppressing discoloration of oils and fats during storage when diatomaceous earth is used as a filter aid in the filtration process. [Modes for carrying out the invention]

[0010] [Method for producing oils and fats] The method for producing oils and fats according to an embodiment of the present invention (hereinafter referred to as "this embodiment") includes a filtration step of filtering the oils and fats to be refined using diatomaceous earth as a filter aid, and includes one or more steps selected from the following steps A to C, or step D. Step A: A step following the filtration step, in which the oil to be refined is treated with a solid organic acid at a concentration of 8 ppm or higher. Step B: A step in which the oil to be refined is treated with an organic acid at a concentration of 8 ppm or higher, prior to the filtration step. Step C: A step in which, after the filtration step, the oil to be refined is washed with water at least 10 times the mass of the diatomaceous earth. Step D: A step following the filtration step, in which the oil to be refined is treated with an organic acid at a concentration of 5 ppm or more, and then the oil to be refined is washed with water at a concentration of at least twice the mass of the diatomaceous earth.

[0011] (Filtration process) The filtration step in the method for producing oils and fats according to this embodiment is a step of filtering the oils and fats to be refined using diatomaceous earth as a filter aid.

[0012] The type of diatomaceous earth used as a filter aid is not particularly limited; any diatomaceous earth that can be used in the oil and fat manufacturing process can be used. For example, commercially available diatomaceous earth filter aids (manufactured by Showa Chemical Industry Co., Ltd.) can be used.

[0013] Also, the amount of diatomaceous earth added to the oil or fat is not particularly limited and can be appropriately determined according to the type of the oil or fat, etc. For example, it can be added at a ratio of 0.1 to 5% by mass based on the oil or fat to be refined. Other filtration conditions such as the treatment temperature can also be set as appropriate.

[0014] In the method for producing an oil or fat according to this embodiment, the filtration step may be performed at any stage. For example, it can be performed before or after general decolorization steps, dewaxing steps, deodorization steps, etc. that are used as the oil or fat purification steps, or it can also be performed simultaneously with these steps. For example, it is preferably performed in the dewaxing step or after the deodorization step.

[0015] The method for producing an oil or fat according to this embodiment can be applied to the production of generally known oils or fats. For example, it can be applied to the production of vegetable oils or fats such as soybean oil, rapeseed oil, cottonseed oil, sunflower oil, safflower oil, corn oil, rice bran oil, sesame oil, olive oil, perilla oil, linseed oil, peanut oil, grape seed oil, coconut oil, palm kernel oil, palm oil, etc. In terms of the relationship with the problems of the present invention, it is suitable for the production of oils or fats containing substances that can cause coloring of the oil or fat during storage, and all or part of such substances can be removed by steps A to D. Although the coloring-causing substances are unknown, it is considered that one of the reasons is that tocopherol becomes a colored product due to the influence of substances derived from diatomaceous earth.

[0016] (Step A) Step A in the method for producing an oil or fat according to this embodiment is a step of treating the oil or fat to be refined with a solid organic acid of 8 ppm or more based on the oil or fat to be refined after the filtration step.

[0017] "After the filtration step" includes the case of performing it after the filtration step and the case of performing it simultaneously with the filtration step, but it is preferably performed immediately after the filtration step.

[0018] Examples of solid organic acids include crystals such as citric acid, malic acid, tartaric acid, lactic acid, acetic acid, oxalic acid, succinic acid, ascorbic acid, and erythorbic acid. Among them, citric acid crystals are preferred. Since the coloring suppression effect is less likely to appear in an aqueous solution of an organic acid, a solid organic acid is preferred.

[0019] The solid organic acid is added at 8 ppm or more based on the mass of the oil or fat to be refined. It is preferably added at 10 ppm or more, more preferably at 20 ppm or more, more preferably at 25 ppm or more, more preferably at 30 ppm or more, more preferably at 35 ppm or more, more preferably at 40 ppm or more, even more preferably at 45 ppm or more, and most preferably at 50 ppm or more based on the mass of the oil or fat to be refined. The upper limit of the addition amount is not particularly limited, but it is preferably 2000 ppm or less, more preferably 1800 ppm or less, more preferably 1600 ppm or less, more preferably 1400 ppm or less, more preferably 1200 ppm or less, more preferably 1000 ppm or less, even more preferably 800 ppm or less, and most preferably 600 ppm or less based on the mass of the oil or fat to be refined.

[0020] The solid organic acid is preferably added to the oil or fat to be refined in an amount of 200 ppm to 80,000 ppm based on the mass of the diatomaceous earth used in the above filtration step. It is more preferably added in an amount of 230 ppm to 10,000 ppm, more preferably 230 ppm to 5000 ppm, even more preferably 230 ppm to 1300 ppm, and most preferably 250 ppm to 500 ppm.

[0021] Other treatment methods and treatment conditions can be set as appropriate. For example, after adding a solid organic acid to the oil or fat, it is stirred so that the whole is mixed, heated at 0 to 90 °C for 5 to 60 minutes, then cooled, and the oil or fat is suction-filtered to remove the solid content.

[0022] (Step B) Step B in the method for producing oils and fats according to this embodiment is a step in which the oils and fats to be purified are treated with an organic acid at a concentration of 8 ppm or higher, prior to the filtration step.

[0023] The phrase "before the filtration process" includes both performing the process immediately before the filtration process and performing it several steps before the filtration process, but it is preferable to perform it immediately before the filtration process.

[0024] Examples of organic acids include citric acid, malic acid, tartaric acid, lactic acid, acetic acid, oxalic acid, succinic acid, ascorbic acid, and erythorbic acid, but citric acid, malic acid, or tartaric acid are preferred. Not limited to solid organic acids, aqueous solutions of organic acids may also be used.

[0025] The organic acid is added at a concentration of 8 ppm or more relative to the mass of the oil or fat to be refined. Preferably, it is added at a concentration of 10 ppm or more, more preferably at 20 ppm or more, more preferably at 25 ppm or more, more preferably at 30 ppm or more, more preferably at 35 ppm or more, more preferably at 40 ppm or more, even more preferably at 45 ppm or more, and most preferably at 50 ppm or more. The upper limit of the amount added is not particularly limited, but preferably at 2000 ppm or less, more preferably at 1800 ppm or less, more preferably at 1600 ppm or less, more preferably at 1400 ppm or less, more preferably at 1200 ppm or less, more preferably at 1000 ppm or less, even more preferably at 800 ppm or less, and most preferably at 600 ppm or less, relative to the oil or fat to be refined.

[0026] It is preferable to add an amount of organic acid to the oil to be refined in a quantity of 200 ppm to 80,000 ppm relative to the mass of diatomaceous earth used in the above filtration process, more preferably 300 ppm to 10,000 ppm, even more preferably 500 ppm to 8,000 ppm, even more preferably 3,000 ppm to 7,000 ppm, and most preferably 4,000 ppm to 6,000 ppm.

[0027] Other processing methods and conditions can be set as appropriate. For example, an organic acid can be added to the oil as an aqueous solution, then the mixture can be stirred at 80-120°C under reduced pressure while dehydrating, cooled, and the oil can be filtered by suction to remove solids. Alternatively, an organic acid can be added to the oil, stirred until the mixture is well combined, heated at 0-90°C for 5-60 minutes, cooled, and the oil can be filtered by suction to remove solids.

[0028] (Process C) Step C in the method for producing oils and fats according to this embodiment is a step in which, after the filtration step, the oils and fats to be refined are washed with water at least 10 times the mass of the diatomaceous earth.

[0029] The phrase "after the filtration process" includes both performing the process immediately after the filtration process and performing it several steps after the filtration process, but it is preferable to perform it immediately after the filtration process.

[0030] The amount of water used in the rinsing process shall be 10 times or more by mass of the diatomaceous earth (mass) used in the filtration process described above. Preferably, it shall be 11 times or more by mass of the diatomaceous earth, more preferably 12 times or more by mass, more preferably 13 times or more by mass, more preferably 14 times or more by mass, more preferably 15 times or more by mass, more preferably 20 times or more by mass, even more preferably 30 times or more by mass, and most preferably 40 times or more by mass. The upper limit of the amount of water is not particularly limited, but preferably 200 times or less by mass of the diatomaceous earth, more preferably 150 times or less by mass, more preferably 120 times or less by mass, more preferably 100 times or less by mass, more preferably 90 times or less by mass, more preferably 80 times or less by mass, even more preferably 70 times or less by mass, and most preferably 60 times or less by mass.

[0031] The rinsing process can be done once or in multiple stages.

[0032] Other processing methods and conditions can be set as appropriate. For example, after adding washing water to the oil, the mixture is thoroughly shaken with a shaker or similar device to ensure complete mixing, and then centrifugal separation is performed to recover the oil phase. Furthermore, it is preferable to dehydrate the obtained oil phase (for example, at 60-120°C under reduced pressure for 5-60 minutes) to remove any remaining water.

[0033] (Process D) Step D in the method for producing oils and fats according to this embodiment is a step in which, after the filtration step, the oils and fats to be refined are treated with an organic acid of 5 ppm or more, and then the oils and fats to be refined are washed with water at least twice the mass of the diatomaceous earth.

[0034] The phrase "after the filtration process" is as explained in process A. The phrase "after the process of treating the oils and fats to be refined with organic acids" includes cases where it is performed immediately after the organic acid treatment process and cases where it is performed several steps after the organic acid treatment process, but it is preferable to perform it immediately after the organic acid treatment process.

[0035] The "organic acids" are as explained in step B.

[0036] The organic acid is added at a concentration of 5 ppm or more relative to the mass of the oil or fat to be refined. Preferably, it is added at a concentration of 6 ppm or more, more preferably at 7 ppm or more, more preferably at 8 ppm or more, more preferably at 9 ppm or more, more preferably at 10 ppm or more, more preferably at 40 ppm or more, even more preferably at 45 ppm or more, and most preferably at 50 ppm or more. The upper limit of the amount added is not particularly limited, but preferably at 2000 ppm or less, more preferably at 1800 ppm or less, more preferably at 1600 ppm or less, more preferably at 1400 ppm or less, more preferably at 1200 ppm or less, more preferably at 1000 ppm or less, even more preferably at 800 ppm or less, and most preferably at 600 ppm or less, relative to the oil or fat to be refined.

[0037] The organic acid is preferably added to the oil to be refined in an amount of 100 ppm to 80,000 ppm relative to the mass of diatomaceous earth used in the above filtration process, more preferably 100 ppm to 5,000 ppm, even more preferably 125 ppm to 3,000 ppm, even more preferably 125 ppm to 1,000 ppm, and most preferably 125 ppm to 600 ppm.

[0038] The amount of water used in the rinsing process shall be at least 2 times the mass of the diatomaceous earth (mass) used in the filtration process described above. Preferably, it shall be at least 3 times the mass of the diatomaceous earth, more preferably 4 times or more, more preferably 5 times or more, more preferably 6 times or more, more preferably 7 times or more, more preferably 8 times or more, even more preferably 9 times or more, and most preferably 10 times or more. The upper limit of the amount of water is not particularly limited, but preferably 200 times or less the mass of the diatomaceous earth, more preferably 150 times or less, more preferably 120 times or less, more preferably 100 times or less, more preferably 90 times or less, more preferably 80 times or less, even more preferably 70 times or less, and most preferably 60 times or less.

[0039] The rinsing process can be done once or in multiple stages.

[0040] Other processing methods and conditions can be set as appropriate, as explained in steps A to C.

[0041] The method for producing oils and fats according to this embodiment includes one or more steps selected from steps A to C above, or step D. It may be any one of steps A to C, or a combination of two or more of them. It is preferable to perform step C after step A or step B. When two or more steps are combined, the amount of organic acid added during the organic acid treatment in step A or step B and / or the amount of washing water during the washing treatment in step C can be reduced compared to when steps A to C are performed individually, as in step D. It is preferable not to perform the step of treating the oils and fats to be refined with phosphoric acid in combination with steps A to D, as this may adversely affect the effects of the present invention.

[0042] (Other processes) The method for producing oils and fats according to this embodiment may include, in addition to the steps described above, generally performed oil and fat refining steps. Specifically, it may include, for example, degumming steps, deacidification steps, decolorization steps, dewaxing steps, and deodorization steps.

[0043] [Method for suppressing discoloration of oils and fats] The method for suppressing discoloration of oils and fats according to this embodiment includes a filtration step of filtering the oils and fats to be refined using diatomaceous earth as a filter aid, and includes one or more steps selected from the following steps A to C, or step D. Step A: A step following the filtration step, in which the oil to be refined is treated with a solid organic acid at a concentration of 8 ppm or higher. Step B: A step in which the oil to be refined is treated with an organic acid at a concentration of 8 ppm or higher, prior to the filtration step. Step C: A step in which, after the filtration step, the oil to be refined is washed with water at least 10 times the mass of the diatomaceous earth. Step D: A step following the filtration step, in which the oil to be refined is treated with an organic acid at a concentration of 5 ppm or more, and then the oil to be refined is washed with water at a concentration of at least twice the mass of the diatomaceous earth.

[0044] The explanation of each step (including definitions of terms) is as described in the section on the method for producing oils and fats according to this embodiment.

[0045] The present invention will now be described with reference to examples, but the present invention is not limited to these examples. [Examples]

[0046] Example 1 (Manufacturing method including step A) <Manufacturing of oils and fats 1-14> Deodorized rapeseed oil (high oleic acid, low linolenic acid rapeseed oil that has undergone a deodorization process, manufactured by Nisshin Oillio Group Ltd.; the same applies in the following examples) in a container was to which diatomaceous earth filter aid (product name "Radiolite #500", manufactured by Showa Chemical Industry Co., Ltd.; the same applies in the following examples) was added so that the amount of diatomaceous earth filter aid was 0% by mass or 4% by mass relative to the rapeseed oil, as described in Tables 1 and 2. Then, the headspace of the container was replaced with nitrogen, and the container was shaken up and down to mix the contents, and heated at 80°C for 30 minutes. After standing in the dark at room temperature for 2 hours, the diatomaceous earth filter aid was removed by suction filtration to obtain oil that had undergone the filtration process.

[0047] The obtained oils and fats, along with citric acid crystals, DL-malic acid crystals, L-tartaric acid crystals, or 98% phosphoric acid, were placed in 100 ml resin containers in the amounts specified in Tables 1 and 2. The citric acid crystals, DL-malic acid crystals, and L-tartaric acid crystals were reagents manufactured by Kanto Chemical Co., Ltd. The 98% phosphoric acid was reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. The headspace of the container was purged with nitrogen, and the container was shaken up and down to ensure thorough mixing. The mixture was then heated at 80°C for 30 minutes. This was then allowed to cool at room temperature in the dark for 1 hour. The oils and fats were filtered by suction to remove solids, and these were designated as oils 1-14.

[0048] <Manufacturing of oils and fats 15-18> To the deodorized rapeseed oil in the container, diatomaceous earth filter aid was added in a manner described in Table 3, such that the amount of diatomaceous earth filter aid was 0% by mass or 4% by mass relative to the rapeseed oil. Then, the headspace of the container was purged with nitrogen, and the container was shaken up and down to mix the contents, and heated at 80°C for 30 minutes. After standing in a dark place at room temperature for 2 hours, the diatomaceous earth filter aid was removed by suction filtration to obtain the oil that had undergone the filtration process.

[0049] The obtained oils and fats, along with a citric acid aqueous solution (prepared by dissolving citric acid crystals (manufactured by Kanto Chemical Co., Ltd.) in deionized water to obtain a 2.5% or 10% solution), were placed in 100 ml plastic containers in the amounts shown in Table 3. The mixtures were shaken at a speed of 250 reciprocations per minute for 20 minutes at room temperature using a shaker, and then centrifuged at 3000 rpm for 5 minutes. The oil phase portion after centrifugation was filtered by suction and was designated as oils 15-18.

[0050] <Preservation Test> Oils 1-18 were measured out in 15g portions and placed into jars measuring 5cm in diameter and 9cm in height. The lids were then sealed and the jars were stored in an airtight container at 80°C for 4 days.

[0051] (Color tone: Y+10R value) The color intensity of the test oils was measured using a Lovibond PFX995 colorimeter (The Tintometer Limited) with a 1-inch cell to determine the yellow chromaticity (Y value) and red chromaticity (R value). The Y value + 10 × R value (hereinafter, Y+10R) was calculated and evaluated. The results are shown in Tables 1-3. A smaller Y+10R value indicates a lighter color, while a larger Y+10R value indicates a darker color.

[0052] (Calculation of degree of coloring) The degree of discoloration was calculated using the Y+10R value after storage at 80°C for 4 days. For oils 3-14, the degree of discoloration was calculated by setting the Y+10R value of oil 1 to 0% and the Y+10R value of oil 2 to 100%. For oils 17 and 18, the degree of discoloration was calculated by setting the Y+10R value of oil 15 to 0% and the Y+10R value of oil 16 to 100%. The results are shown in Tables 1-3. Note that the heating history in the manufacturing process before the storage test differs between oils 1-14 and oils 15-18.

[0053] [Table 1]

[0054] [Table 2]

[0055] [Table 3]

[0056] <Effects of organic acid crystals and phosphoric acid> In oil 4, to which 10 ppm of citric acid crystals were added, the degree of discoloration was suppressed to 8%. In oils 5-11, where the amount of citric acid crystals was increased, the degree of discoloration was suppressed to 33-67%. In oils 12 and 13, discoloration could be suppressed with organic acids other than citric acid. In oil 14, phosphoric acid was added, but discoloration could not be suppressed. In oils 17 and 18, citric acid aqueous solution was added, but discoloration could not be suppressed.

[0057] Example 2 (Manufacturing method including step C) <Manufacturing of oils and fats 19-28> To the deodorized rapeseed oil in the container, diatomaceous earth filter aid was added in amounts of 0%, 2%, or 4% by mass relative to the rapeseed oil, as described in Tables 4-6. Then, the headspace of the container was purged with nitrogen, and the container was shaken up and down to ensure thorough mixing. The mixture was then heated at 80°C for 30 minutes. After standing at room temperature in the dark for 2 hours, the diatomaceous earth filter aid was removed by suction filtration to obtain the filtered oil.

[0058] The obtained oils and greases, along with the washing water (ion-exchanged water), were placed in resin centrifuge tubes in the amounts shown in Tables 4-6. After shaking at a speed of 150 reciprocations per minute for 5 minutes using a shaker, centrifugation was performed at 3000 rpm for 5 minutes. Oils 26 and 28, which were washed with 1x the amount of washing water, underwent a first rinse with 0.5x the amount of washing water. 18g of the oil phase after centrifugation was transferred to another resin centrifuge tube, and 0.5x the amount of washing water was added for a second rinse in the same manner as the first. These oil phases after centrifugation were designated as oils 19-28.

[0059] <Preservation Test> Fats 19-28 were weighed out in 15g portions and placed into jars measuring 5cm in diameter and 9cm in height. The lids were sealed and the jars were stored in airtight containers at 80°C for 4 days. The Y+10R values ​​were calculated in the same manner as in Example 1. The results are shown in Tables 4-6.

[0060] (Calculation of degree of coloring) The degree of discoloration was calculated using the Y+10R value after storage at 80°C for 4 days. For oils 20-26, the degree of discoloration was calculated using the Y+10R value of oil 15 as 0% and the Y+10R value of oil 19 as 100%. For oils 27 and 28, the degree of discoloration was calculated using the Y+10R value of oil 15 as 0% and the Y+10R value of oil 16 as 100%. The results are shown in Tables 4-6.

[0061] [Table 4]

[0062] [Table 5]

[0063] [Table 6]

[0064] <Effects of flushing> The diatomaceous earth filter aid was effective when the amount of washing water [B / (A / 100)] was 12.5 times or more, and the effect was maximized when it was 25 times or more.

[0065] Example 3 (Manufacturing method including step D) <Manufacturing of oils and fats 29-35> Oils 3, 5, or 17 and washing water (ion-exchanged water) were placed in resin centrifuge tubes in the amounts shown in Tables 7-9. The tubes were shaken using a shaker at a speed of 150 reciprocations per minute for 5 minutes, and then centrifuged at 3000 rpm for 5 minutes. The oil phases after these centrifuges were designated as oils 29-35. Note that the manufacturing method for oil 34 also includes steps A and C.

[0066] <Preservation Test> Fats 29-34 were weighed out in 15g portions and placed in jars measuring 5cm in diameter and 9cm in height. The lids were sealed and the jars were stored in airtight containers at 80°C for 4 days. The Y+10R values ​​were calculated in the same manner as in Example 1. The results are shown in Tables 7-9.

[0067] (Calculation of degree of coloring) The degree of discoloration was calculated using the Y+10R value after storage at 80°C for 4 days. For oils 29-34, the degree of discoloration was calculated by setting the Y+10R value of oil 1 to 0% and the Y+10R value of oil 2 to 100%. For oil 35, the degree of discoloration was calculated by setting the Y+10R value of oil 15 to 0% and the Y+10R value of oil 16 to 100%. The results are shown in Tables 7-9.

[0068] [Table 7]

[0069] [Table 8]

[0070] [Table 9]

[0071] <Effects of using organic acids and water washing together> By using organic acid treatment and water washing in combination, it was possible to reduce the amount of organic acid added during organic acid treatment and / or the amount of washing water used during water washing compared to the cases of process A and process C.

[0072] Example 4 (Manufacturing method including step B) <Manufacturing of oils and fats 36-39> To the deodorized rapeseed oil in the container, a 20% citric acid aqueous solution (prepared by dissolving citric acid crystals (manufactured by Kanto Chemical Co., Ltd.) in ion-exchanged water) was added to achieve citric acid concentrations of 0 ppm, 10 ppm, or 100 ppm by mass. The mixture was heated to 105°C under reduced pressure while stirring. Further dehydration was carried out at 105°C for 10 minutes, and the mixture was cooled to room temperature under reduced pressure. The mixture was then filtered by suction at atmospheric pressure to obtain oils treated with 0 ppm, 10 ppm, or 100 ppm of citric acid.

[0073] The obtained oils were mixed with diatomaceous earth filter aids in the amounts shown in Table 10, and heated at 80°C for 30 minutes under a nitrogen atmosphere. After standing for 1 hour at room temperature in the dark, the diatomaceous earth filter aids were removed by suction filtration, and the resulting mixtures were designated as oils 36-39.

[0074] <Preservation Test> Oils 36-39 were weighed out in 15g portions and placed into jars measuring 5cm in diameter and 9cm in height. The lids were sealed and the jars were stored in airtight containers at 60°C for 14 days. The Y+10R values ​​were calculated in the same manner as in Example 1. The results are shown in Table 10.

[0075] (Calculation of degree of coloring) The degree of discoloration was determined using the Y+10R value after storage at 60°C for 14 days. The degree of discoloration was calculated by setting the Y+10R value of oil 36 to 0% and the Y+10R value of oil 37 to 100%. The results are shown in Table 10.

[0076] [Table 10]

[0077] <Effects of applying organic acid treatment before the filtration process using diatomaceous earth filter aid> When organic acid treatment is performed before the filtration process using diatomaceous earth filter aid, a particularly effective result was observed when the organic acid concentration was 100 ppm.

Claims

1. A method for producing fats and oils, comprising a filtration step of filtering fats and oils to be refined using diatomaceous earth as a filter aid, A method for producing fats and oils, comprising one or more steps selected from the following steps A to C, or step D: Step A: After the filtration step, a step of treating the oil to be refined with a solid organic acid of 8 ppm or more relative to the oil to be refined. Step B: A step of treating the oil to be refined with 8 ppm or more of an organic acid relative to the oil to be refined before the filtration step. Step C: After the filtration step, the oil to be refined is washed with water in an amount 10 times by mass or more of the diatomaceous earth. Step D: After the filtration step, after treating the oil to be purified with 5 ppm or more of an organic acid relative to the oil to be purified, washing the oil to be purified with water at least twice the mass of the diatomaceous earth.

2. The method for producing fats and oils according to claim 1, comprising the step A.

3. The method for producing an oil or fat according to claim 1 or claim 2, comprising the step B.

4. The method for producing fats and oils according to any one of claims 1 to 3, comprising the step C.

5. The method for producing fats and oils according to claim 1, comprising the step A or the step B, and the step C performed after the step A or the step B.

6. The method for producing fats and oils according to claim 1, comprising the step D.

7. A method for suppressing coloration of fats and oils, comprising a filtration step of filtering fats and oils to be refined using diatomaceous earth as a filter aid, A method for suppressing discoloration of fats and oils, comprising one or more steps selected from the following steps A to C, or step D. Step A: After the filtration step, a step of treating the oil to be refined with a solid organic acid of 8 ppm or more relative to the oil to be refined. Step B: A step of treating the oil to be refined with 8 ppm or more of an organic acid relative to the oil to be refined before the filtration step. Step C: After the filtration step, the oil to be refined is washed with water in an amount 10 times by mass or more of the diatomaceous earth. Step D: After the filtration step, after treating the oil to be purified with 5 ppm or more of an organic acid relative to the oil to be purified, washing the oil to be purified with water at least twice the mass of the diatomaceous earth.

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