Refining liquid oils and method of controlling p-anisidine value

Abstract

A method of refining a liquid oil and a method of controlling the p-anisidine value of a first level of a liquid oil after bleaching, comprising: contacting a liquid oil that has not undergone a prior bleaching step or a prior deodorization step with a 5 adsorbent for bleaching, wherein the adsorbent comprises activated carbon, silica, or a combination thereof, and wherein the first level of the p-anisidine value after the bleaching step is maintained at no more than about 190%, or no more than about 170%, or no more than about 125% of a second level of the p-anisidine value before the bleaching step.

Description

Technical Field

[0001] This invention relates to a method for refining liquid oil, and more particularly to controlling the p-anisidine value during the refining process. Background Technology

[0002] Food quality and safety have received widespread attention. Liquid oils, such as sunflower oil, contain high levels of unsaturated fatty acids, especially polyunsaturated fatty acids, which are more easily oxidized. The anisidine value is a secondary product of oil oxidation, reflecting the degree of oxidation. Existing bleaching methods used for refining liquid oils can lead to a significant increase in the anisidine value, meaning that these methods result in a higher degree of oil oxidation.

[0003] Therefore, there is a need to develop a method for refining liquid oil in which the level of anisidine value is controlled. Summary of the Invention

[0004] The present invention relates to a method for refining liquid oil, comprising: contacting liquid oil that has not undergone a previous bleaching step or a previous deodorization step with an adsorbent for bleaching, wherein the adsorbent comprises activated carbon, silica, or a combination thereof, and wherein a first level of p-anisidine value after the bleaching step is maintained at no more than about 190%, or no more than about 170%, or no more than about 125% of the second level of p-anisidine value before the bleaching step.

[0005] The present invention relates to a method for controlling the p-anisidine value of a liquid oil at a first level after decolorization, comprising: contacting the liquid oil, which has not yet undergone a previous bleaching step or a previous deodorization step, with an adsorbent for bleaching; and deodorizing the bleached oil with steam at a temperature of 220°C to 300°C for 15 minutes to 1 hour, wherein the adsorbent comprises activated carbon, silica, or a combination thereof, and wherein the p-anisidine value at the first level after the bleaching step is controlled to not exceed about 190% of the p-anisidine value at the second level before the bleaching step. Attached Figure Description

[0006] Figure 1 A diagram illustrating the degumming, neutralization, and bleaching process according to one aspect of the invention is shown.

[0007] Figure 2 A diagram illustrating a deodorization process according to one aspect of the present invention is shown. Detailed Implementation

[0008] Unless otherwise stated, all measurements, weights, lengths, etc., are in metric units, and all temperatures are in degrees Celsius. It should be understood that, unless otherwise specifically indicated, the materials, compounds, chemicals, etc., described herein are generally commodities and / or industry-standard items available from a wide range of suppliers and sources worldwide.

[0009] Throughout the document, values ​​expressed in range format should be interpreted flexibly to include not only the values ​​explicitly listed as limits of the range, but also all individual values ​​or subranges covered within the range, as if each value and subrange were explicitly listed. For example, the range “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not only about 0.1% to about 5%, but also individual values ​​(e.g., 1%, 2%, 3%, and 4%) and subranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the specified range. Unless otherwise stated, the statement “about X to Y” has the same meaning as “about X to about Y”. Similarly, unless otherwise stated, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z”.

[0010] As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include multiple referents. For example, the indexing of “liquid oil” covers a single type of liquid oil as well as two or more types of liquid oil. It should be understood that any term in the singular form may include its plural counterpart and vice versa.

[0011] Unless otherwise specified, the term "or" is used to refer to a non-exclusive "or". The statement "at least one of A and B" has the same meaning as "A, B or A and B".

[0012] As used herein, the terms “for example,” “to exemplify,” “such as,” “like,” or “including” are intended to provide examples that further illustrate a more general subject. Unless otherwise stated, these examples are provided merely to aid in understanding the application of the descriptions in this disclosure and are not intended to be limiting in any way.

[0013] As used herein, the term “about” allows for a degree of variability in the value or range, for example, within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% of the specified limit of the specified value or range, and includes the exact specified value or range.

[0014] The term "controlling the p-anisidine level" means maintaining the p-anisidine level of the first level after the bleaching step at the same level as the p-anisidine level of the second level before the bleaching step, or not exceeding about 190%, or about 170%, or about 125%, or 110% of the p-anisidine level of the second level.

[0015] The present invention provides a method for refining liquid oil, comprising: contacting liquid oil that has not undergone a previous bleaching step or a previous deodorization step with an adsorbent for bleaching, wherein the adsorbent comprises activated carbon, silica, or a combination thereof, and wherein a first level of p-anisidine value after the bleaching step is maintained at the same level as a second level of p-anisidine value before the bleaching step, or not exceeding about 190%, or not exceeding about 170%, or not exceeding about 125%, or not exceeding 110% of the second level of p-anisidine value.

[0016] The present invention also provides a method for controlling the p-anisidine value of a liquid oil at a first level after decolorization, comprising: contacting the liquid oil, which has not yet undergone a previous bleaching step or a previous deodorization step, with an adsorbent for bleaching; and deodorizing the bleached oil with steam at a temperature of 220°C to 300°C (or 220°C to 280°C, or 220°C to 260°C, or 200°C to 250°C, or 200°C to 220°C) for 15 minutes to 1 hour (or 15 minutes to 45 minutes, or 20 minutes to 40 minutes, or 15 minutes to 30 minutes), wherein the adsorbent comprises activated carbon, silica, or a combination thereof, and wherein the p-anisidine value at the first level after the bleaching step is controlled to be no more than about 190% of the p-anisidine value at the second level before the bleaching step (or no more than about 170%, or no more than about 125%, or no more than about 110%, or the same level).

[0017] In one aspect, the liquid oil prior to treatment by the method of the present invention is crude oil. In one aspect, the liquid oil prior to treatment by the method of the present invention has never undergone a prior bleaching or deodorizing step. In one aspect, the liquid oil prior to treatment by the method of the present invention has undergone a degumming and neutralization process. In one aspect, the liquid oil prior to treatment by the method of the present invention is a degummed and neutralized oil that has never undergone a prior bleaching or deodorizing step.

[0018] In one aspect, the p-anisidine value of the first level after the bleaching step is maintained at 100% to 190% of the p-anisidine value of the second level before the bleaching step. In another aspect, the p-anisidine value of the first level after the bleaching step is maintained at the same level as the p-anisidine value of the second level before the bleaching step, or not exceeding about 190%, or not exceeding about 170%, or not exceeding 150%, or not exceeding about 125%, or not exceeding 110% of the p-anisidine value of the second level. In one aspect, the p-anisidine value of the second level before the bleaching step is the p-anisidine value level of the degummed and neutralized liquid oil before the bleaching step. In one aspect, the p-anisidine value of the first level after the bleaching step is maintained at not exceeding about 800%, or not exceeding about 700%, or not exceeding about 600% of the p-anisidine value level of the original liquid oil. In one aspect, the p-anisidine value of the first level after the bleaching step is maintained at 100% to 800% of the p-anisidine value level of the original liquid oil.

[0019] In one respect, the first level of anisidine value after the bleaching step is less than about 4, or less than about 3, or less than about 2.5 or less than about 2.3.

[0020] In one aspect, the amount of adsorbent is about 0.05% to 10% by weight, or 0.5% to 5% by weight, or 0.5% to 2% by weight, or 0.5% to 1% by weight, or 0.4% to 0.9% by weight of the liquid oil. In another aspect, the liquid oil before bleaching is a degummed and neutralized liquid oil.

[0021] In one aspect, the method includes: a) optionally degumming the liquid oil; b) neutralizing the degummed oil; c) bleaching the neutralized oil with an adsorbent; and d) deodorizing the bleached oil.

[0022] On the one hand, such as Figure 1 As shown, the method includes: heating the raw material (i.e., the original liquid oil), adding food-grade H3PO4 to degumm the oil to obtain degummed oil, adding food-grade NaOH to neutralize the degummed oil to obtain degummed and neutralized oil; heating the degummed and neutralized oil and centrifuging the oil; reheating the oil; washing the oil with food-grade H3PO4 or citric acid and drying the oil; adding a food-grade adsorbent to bleach the oil to obtain bleached oil; filtering the bleached oil; cooling the filtered oil and storing the oil.

[0023] In one aspect, such as Figure 2 As shown, the deodorization process includes: filtration Figure 1 The process involves: bleaching the oil; degassing the oil; deodorizing the oil to obtain deodorized oil; cooling the deodorized oil; filtering the oil; storing the filtered oil; and outputting the filtered oil and its load.

[0024] In one aspect, the deodorization step in d) is carried out at a temperature of 220°C to 300°C, or 220°C to 280°C, or 220°C to 260°C, or 200°C to 250°C, or 200°C to 220°C. In another aspect, the deodorization step in d) is carried out at this temperature for 15 minutes to 1 hour, or 15 minutes to 45 minutes, or 20 minutes to 40 minutes, or 15 minutes to 30 minutes.

[0025] In one aspect, steam is used in step d) to deodorize the bleached oil. In another aspect, nitrogen is not used in step d) to deodorize the bleached oil.

[0026] In one aspect, the oil contains more than 80% by weight of unsaturated fatty acids, preferably polyunsaturated fatty acids. In another aspect, the liquid oil contains 80% to 99% by weight, 80% to 95% by weight, or 80% to 90% by weight of unsaturated fatty acids, preferably polyunsaturated fatty acids.

[0027] In one respect, the oil is a liquid vegetable oil. In another respect, the oil is selected from the group consisting of: coconut oil, corn oil, canola oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soybean oil, sunflower oil, almond oil, beech nut oil, Brazil nut oil, cashew oil, hazelnut oil, macadamia nut oil, mongongo nut oil, pecan oil, pine nut oil, pistachio oil, walnut oil, pumpkin seed oil, grapefruit seed oil, lemon oil, orange oil, bitter melon oil, gourd oil, buffalo gourd oil, walnut pumpkin seed oil, egusi seed oil, watermelon seed oil, acai oil, black seed oil, blackcurrant seed oil, borage seed oil, evening primrose oil, flaxseed oil, amaranth oil, apricot oil, apple seed oil, argan oil, avocado oil, babassu oil, and ben. Oils, including camphor tallow nut oil, kapok oil, carob pod oil, cocklebur oil, cohune oil, coriander seed oil, jujube seed oil, dika oil, flaxseed oil, grapeseed oil, kapok seed oil, kenaf seed oil, lallemantia oil, mafura oil, marula oil, meadowfoam seed oil, mustard oil, sunflower seed oil, nutmeg butter, okra seed oil, papaya seed oil, perilla seed oil, persimmon seed oil, pequi oil, pili nut oil, pomegranate seed oil, pracaxi oil, virgin pracaxi oil, plum kernel oil, quinoa oil, ramtil oil, rice bran oil, royal oil, and sacha inchi. Inchi oil, sapote oil, shea oil, shea butter, taramira oil, tea seed oil, thistle oil, tiger nut oil, tobacco seed oil, tomato seed oil, wheat germ oil, and combinations thereof.

[0028] In one respect, the oil includes sunflower oil, canola oil, or a combination thereof.

[0029] In one aspect, the liquid oil is contacted with an adsorbent and an additional adsorbent for bleaching. In one aspect, the additional adsorbent is clay. In one aspect, the additional adsorbent is acidic clay. In one aspect, the weight ratio of the adsorbent to the additional adsorbent is in the range of 1:1.5 to 1:4, or 1:1.5 to 1:3, or 1:1.5 to 1:2.5. In one aspect, the clay is acidic white clay or neutral white clay. In one aspect, the amount of the additional adsorbent is from 0.05% by weight to 2% by weight of the liquid oil.

[0030] In one aspect, the particle size of the adsorbent is in the range of 40 μmm to 180 μmm, 40 μmm to 100 μmm, or 50 μmm to 90 μmm, or 70 μmm to 80 μmm, or 75 μmm to 90 μmm, or 75 μmm to 100 μmm. In another aspect, the median particle size of the adsorbent is in the range of 40 μmm to 180 μmm, 40 μmm to 100 μmm, or 50 μmm to 90 μmm, or 70 μmm to 80 μmm, or 75 μmm to 90 μmm, or 75 μmm to 100 μmm.

[0031] In one aspect, the particle size of the adsorbent is measured using a 75 μm sieve. In one aspect, approximately 4% to 50%, 4% to 40%, 8% to 50%, 10% to 40%, and 20% to 50% of the adsorbent fail to pass through the sieve and remain on the sieve as residue, meaning this portion of the adsorbent has a size greater than 75 μm. In one aspect, approximately 2% to 10%, or 3% to 6%, or 4% to 5% of the adsorbent fail to pass through the sieve and remain on the sieve as residue. In one aspect, approximately 20% to 50%, or 30% to 50%, or 30% to 40% of the adsorbent fail to pass through the sieve and remain on the sieve as residue.

[0032] This invention provides refined liquid oils through the methods discussed herein.

[0033] Unbound by theory, the inventors of this invention have discovered that using an adsorbent (i.e., comprising activated carbon, silica, or a combination thereof) to bleach liquid oil that has not undergone a previous bleaching or deodorization step can control the p-anisidine level after bleaching to a lower level compared to other existing adsorbents. The inventors have also discovered that steam deodorization and higher temperatures can also help control the p-anisidine level to a lower level. To reduce the deodorization temperature, an adsorbent comprising activated carbon, silica, or a combination thereof can be used to bleach liquid oil that has not undergone a previous bleaching or deodorization step, and steam deodorization can be used to deodorize the bleached oil.

[0034] The inventors have discovered that if the liquid oil has already undergone a previous bleaching or deodorization step, an adsorbent containing activated carbon, silica, or a combination thereof cannot be used to bleach the liquid oil and control the level of anisidine.

[0035] Representative features of the present invention are listed in the following clauses. These representative features may exist alone or may be combined in any combination with one or more features disclosed in the text of this specification.

[0036] This invention is as described in the following clauses: Clause 1: A method for refining liquid oil, the method comprising: The liquid oil, which has not yet undergone a previous bleaching or deodorization step, is brought into contact with an adsorbent used for bleaching. The adsorbent comprises activated carbon, silica, or a combination thereof, and The p-anisidine value of the first level after the bleaching step is maintained at no more than about 190%, or no more than about 170%, or no more than about 125% of the p-anisidine value of the second level before the bleaching step.

[0037] Clause 2: According to the method of Clause 1, the first level of anisidine value after the bleaching step is less than about 4, or less than about 3, or less than about 2.5 or less than about 2.3.

[0038] Clause 3: The method according to any one of the preceding clauses, wherein the amount of said adsorbent is 0.05% to 10% by weight, or 0.5% to 5% by weight, or 0.5% to 2% by weight of the liquid oil.

[0039] Clause 4: The method according to any one of the preceding clauses, wherein the method comprises: a) Optionally, degumming of the liquid oil; b) Neutralize the degummed oil; c) Bleaching the neutralized oil with the adsorbent; and d) Deodorize the bleached oil Clause 5: The method according to Clause 4, wherein the deodorization step in d) is carried out at a temperature of 220°C to 300°C, or 220°C to 280°C, or 220°C to 260°C.

[0040] Clause 6: The method according to Clause 5, wherein the deodorization step in d) is carried out at the temperature for 15 minutes to 1 hour, or 15 minutes to 45 minutes, or 20 minutes to 40 minutes.

[0041] Clause 7: The method according to any one of Clauses 4 to 6, wherein steam is used in step d) to deodorize the bleached oil.

[0042] Clause 8: The method according to any one of the preceding clauses, wherein the liquid oil contains more than 80% by weight of unsaturated fatty acids.

[0043] Clause 9: The method according to any one of the preceding clauses, wherein the oil is selected from the group consisting of: coconut oil, corn oil, canola oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soybean oil, sunflower oil, almond oil, beech nut oil, Brazil nut oil, cashew oil, hazelnut oil, macadamia nut oil, pecan nut oil, pine nut oil, pistachio oil, walnut oil, pumpkin seed oil, grapefruit seed oil, lemon oil, orange oil, bitter melon oil, gourd oil, buffalo gourd oil, walnut pumpkin seed oil, agave seed oil, watermelon seed oil, acai oil, black seed oil, blackcurrant seed oil, borage seed oil, evening primrose oil, flaxseed oil, amaranth oil, apricot oil, apple seed oil, and argan oil. Avocado oil, babassu oil, bonnet oil, camphor tallow nut oil, scallop oil, carob pod oil, cocklebur oil, cohunni oil, coriander seed oil, jujube seed oil, dica oil, flaxseed oil, grapeseed oil, kapok seed oil, kenaf seed oil, lamantia oil, mafra oil, marula oil, meadowfoam seed oil, mustard oil, sunflower seed oil, nutmeg butter, okra seed oil, papaya seed oil, perilla seed oil, persimmon seed oil, pegki oil, piry nut oil, pomegranate seed oil, plakashi oil, virgin plakashi oil, plum kernel oil, quinoa oil, ramtil oil, rice bran oil, royal oil, incain oil, sapo oil, sajer oil, shea butter, taramia oil, tea seed oil, thistle oil, tiger nut oil, tobacco seed oil, tomato seed oil, wheat germ oil, and combinations thereof.

[0044] Clause 10: A method for controlling a first level of anisidine value in bleached liquid oil, comprising: The liquid oil, which has not yet undergone a previous bleaching or deodorization step, is contacted with an adsorbent used for bleaching; and The bleached oil is deodorized with steam at a temperature of 220°C to 300°C for 15 minutes to 1 hour. The adsorbent comprises activated carbon, silica, or a combination thereof, and The anisidine value of the first level after the bleaching step is controlled to be no more than approximately 190% of the anisidine value of the second level before the bleaching step.

[0045] Clause 11: The method according to Clause 10, wherein the first level of anisidine value after the bleaching step is less than about 4, or less than about 3, or less than about 2.5, or less than about 2.3.

[0046] Clause 12: The method according to any one of Clauses 10 to 11, wherein the amount of said adsorbent is 0.05% to 10% by weight, or 0.5% to 5% by weight, or 0.5% to 2% by weight of the liquid oil.

[0047] Clause 13: The method according to any one of Clauses 10 to 12, wherein the oil contains more than 80% by weight of unsaturated fatty acids.

[0048] Clause 14: The method according to any one of Clauses 10 to 13, wherein the oil comprises sunflower oil, canola oil, or a combination thereof.

[0049] Clause 15: A liquid oil refined by any one of the preceding clauses.

[0050] Example

[0051] The following examples are provided to further illustrate and explain the invention, and should not be construed as limiting in any way.

[0052] Example 1

[0053] The anisidine value is determined according to the method described in "Animal and Vegetable Fats and Oils - Determination of Anisidine Value (GB / T 24304-2009 / ISO 6885:2006, IDT)," which was published by Chinese National Standards on September 30, 2009, and implemented on January 1, 2010.

[0054] The changes in the anisidine value of sunflower oil during the refining process using white clay are listed in Table 1.

[0055] Table 1

[0056] As shown in Table 1, during the refining process, the anisidine value increased significantly after bleaching and decreased after deodorization.

[0057] Example 2

[0058] According to Figure 1 The method shown degummes and neutralizes sunflower oil. Table 2 lists the changes in anisidine values ​​of the same neutralized sunflower oil bleached with different adsorbents.

[0059] Table 2

[0060] Activated carbon-1 has a different particle size than activated carbon-2. When activated carbon-1 is measured through a 75 μm sieve, approximately 4.4% of it does not pass through the sieve and remains as residue. When activated carbon-2 is measured through a 75 μm sieve, approximately 37% of it does not pass through the sieve and remains as residue.

[0061] As shown in Table 2, when 0.5 wt% SiO2, 0.5 wt% activated carbon-1, or 0.5 wt% activated carbon-2 are used as adsorbents for bleaching, the p-anisamine value after bleaching (i.e., the first level of p-anisamine value) can be maintained at no more than 145%, 120%, and 160% of the p-anisamine value before bleaching (i.e., p-anisamine value = 2) (i.e., the second level of p-anisamine value), respectively. When 1 wt% SiO2, 1 wt% activated carbon-1, or 1 wt% activated carbon-2 are used as adsorbents for bleaching, the p-anisamine value after bleaching can be maintained at no more than 115%, 125%, and 115% of the p-anisamine value before bleaching, respectively.

[0062] However, when the adsorbent was any other than these three, the p-anisidine levels after bleaching increased to more than 240% above the pre-bleaching p-anisidine levels. Therefore, activated carbon and silica are more effective than clay in controlling p-anisidine levels.

[0063] Example 3

[0064] According to Figure 1 The method shown degummes and neutralizes canola oil. Table 3 lists the changes in anisidine values ​​when using different adsorbents to bleach the same neutralized canola oil.

[0065] Table 3

[0066] When 1% by weight SiO2, 1% by weight activated carbon-1, or 1% by weight activated carbon-2 are used as adsorbents for bleaching, the p-anisamine level after bleaching can be maintained at no more than 166%, 138%, and 103% of the p-anisamine level before bleaching, respectively.

[0067] However, when the adsorbent was any other than these three, the p-anisidine levels after bleaching increased to more than 200% above the pre-bleaching levels. Therefore, activated carbon and silica are more effective than clay in controlling p-anisidine levels.

[0068] Example 4

[0069] The deodorization process is based on Figure 2 The method shown is used. Sunflower oil is deodorized using different deodorization conditions as shown in Table 4.

[0070] Table 4

[0071] As shown in Table 4, when the deodorization temperature and time are the same (e.g., 216℃, 30 minutes), steam deodorization is more effective than nitrogen deodorization in controlling the anisidine value. Table 4 also shows that higher deodorization temperatures are more effective than lower temperatures in controlling the anisidine value.

[0072] Example 5

[0073] In this embodiment, bleached or refined sunflower oil was used for rebleaching. Activated charcoal was used to rebleach the bleached or deodorized sunflower oil, and the p-anisidine values ​​after rebleaching are listed in Table 5.

[0074] Table 5

[0075] As shown in Table 5, activated carbon can only help slightly reduce the p-anisidine value of bleached or refined oils. Therefore, activated carbon cannot control the p-anisidine value level of liquid oils that have undergone previous bleaching or deodorization steps.

[0076] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the invention pertain. It should also be understood that terms (such as those defined in common dictionaries) should be interpreted as having the same meaning as they have in the context of the relevant art and this disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0077] While this disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and elements may be substituted with equivalents without departing from the scope of this disclosure. Furthermore, many modifications may be made to adapt particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, this disclosure is not limited to the specific embodiments disclosed as the best mode contemplated for carrying out this disclosure, but rather includes all embodiments falling within the scope of the appended claims.

Claims

1. A method for refining liquid oil, comprising: The liquid oil, which has not yet undergone a previous bleaching or deodorization step, is brought into contact with an adsorbent used for bleaching. The adsorbent comprises activated carbon, silica, or a combination thereof, and The p-anisidine value at the first level after the bleaching step is maintained at no more than about 190%, or no more than about 170%, or no more than about 125% of the p-anisidine value at the second level before the bleaching step.

2. The method of claim 1, wherein the p-anisidine value of the first level after the bleaching step is less than about 4, or less than about 3, or less than about 2.5, or less than about 2.

3.

3. The method according to any one of the preceding claims, wherein the amount of the adsorbent is 0.05% to 10% by weight, or 0.5% to 5% by weight, or 0.5% to 2% by weight of the liquid oil.

4. The method according to any one of the preceding claims, wherein the method comprises: a) Optionally, degumming of the liquid oil; b) Neutralize the degummed oil; c) Bleaching the neutralized oil with the adsorbent; as well as d) Deodorize the bleached oil.

5. The method according to claim 4, wherein the deodorization step in d) is carried out at a temperature of 220°C to 300°C, or 220°C to 280°C, or 220°C to 260°C.

6. The method of claim 5, wherein the deodorization step in d) is performed at the temperature for 15 minutes to 1 hour, or 15 minutes to 45 minutes, or 20 minutes to 40 minutes.

7. The method according to any one of claims 4 to 6, wherein steam is used in step d) to deodorize the bleached oil.

8. The method according to any one of the preceding claims, wherein the liquid oil contains more than 80% by weight of unsaturated fatty acids.

9. The method according to any one of the preceding claims, wherein the oil is selected from the group consisting of: coconut oil, corn oil, canola oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soybean oil, sunflower oil, almond oil, beech nut oil, Brazil nut oil, cashew oil, hazelnut oil, macadamia nut oil, pecan nut oil, pine nut oil, pistachio oil, walnut oil, pumpkin seed oil, grapefruit seed oil, lemon oil, orange oil, bitter melon oil, gourd oil, buffalo gourd oil, walnut pumpkin seed oil, agave seed oil, watermelon seed oil, acai oil, black seed oil, blackcurrant seed oil, borage seed oil, evening primrose oil, flaxseed oil, amaranth oil, apricot oil, apple seed oil, and argan oil. Avocado oil, babassu oil, bonnet oil, camphor tallow nut oil, scallop oil, carob pod oil, cocklebur oil, cohunni oil, coriander seed oil, jujube seed oil, dica oil, flaxseed oil, grapeseed oil, kapok seed oil, kenaf seed oil, lamantia oil, mafra oil, marula oil, meadowfoam seed oil, mustard oil, sunflower seed oil, nutmeg butter, okra seed oil, papaya seed oil, perilla seed oil, persimmon seed oil, pegki oil, piry nut oil, pomegranate seed oil, plakashi oil, virgin plakashi oil, plum kernel oil, quinoa oil, ramtil oil, rice bran oil, royal oil, incain oil, sapo oil, sajer oil, shea butter, taramia oil, tea seed oil, thistle oil, tiger nut oil, tobacco seed oil, tomato seed oil, wheat germ oil, and combinations thereof.

10. A method for controlling a first level of anisidine value in bleached liquid oil, comprising: The liquid oil, which has not yet undergone a previous bleaching or deodorization step, is brought into contact with an adsorbent used for bleaching. as well as The bleached oil is deodorized with steam at a temperature of 220°C to 300°C for 15 minutes to 1 hour. The adsorbent comprises activated carbon, silica, or a combination thereof, and The anisidine value at the first level after the bleaching step is controlled to be no more than approximately 190% of the anisidine value at the second level before the bleaching step.

11. The method of claim 10, wherein the first level of anisidine value after the bleaching step is less than about 4, or less than about 3, or less than about 2.5, or less than about 2.

3.

12. The method according to any one of claims 10 to 11, wherein the amount of the adsorbent is 0.05% to 10% by weight, or 0.5% to 5% by weight, or 0.5% to 2% by weight of the liquid oil.

13. The method according to any one of claims 10 to 12, wherein the oil contains more than 80% by weight of unsaturated fatty acids.

14. The method according to any one of claims 10 to 13, wherein the oil comprises sunflower oil, rapeseed oil, or a combination thereof.

15. A liquid oil refined by the method according to any one of the preceding claims.

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