阅读说明：本技术 食用油中缩水甘油酯含量的减少 (Reduction of glycidyl ester content in edible oils ) 是由 B.萨鲁普 于 2018-06-12 设计创作，主要内容包括：一种处理食用油的方法。使食用油与包含环氧转化催化剂的多孔体接触。多孔体的尺寸大于0.5mm。一种处理食用油的系统。系统包含第一处理单元和布置成接收来自第一处理单元的食用油的反应容器。反应容器包含：包含环氧转化催化剂的多孔体,多孔体的尺寸大于0.5mm。包含环氧转化催化剂的多孔体用于处理食用油的用途,多孔体的尺寸大于0.5mm。(A method for treating edible oil is provided. Contacting an edible oil with a porous body comprising an epoxy conversion catalyst. The size of the porous body is greater than 0.5 mm. A system for processing edible oil. The system comprises a first processing unit and a reaction vessel arranged to receive edible oil from the first processing unit. The reaction vessel comprises: a porous body comprising an epoxy conversion catalyst, the porous body having a size greater than 0.5 mm. Use of a porous body comprising an epoxy conversion catalyst, the porous body having a size of greater than 0.5mm, for the treatment of an edible oil.)

1. A method for reducing the amount of 3-and 2-Monochloropropanediol (MCPD), 3-and 2-monochloropropanediol fatty acid esters, and glycidyl esters in a refined or modified edible oil by hydrolysis in the presence of an acid catalyst, characterized in that the refined or modified edible oil is contacted with a fixed bed of more than 1mm porous bodies comprising an acid catalyst comprising at least one of silica-alumina, and gamma alumina.

2. The process of claim 1, wherein the acid catalyst comprises silica-alumina.

3. A method according to claim 1 or 2, wherein the porous body is a shaped body, such as a pellet, extrudate, tablet or granule, prepared by compacting or densifying the microparticles comprising said acid catalyst.

4. A process according to any one of claims 1 to 3, wherein the refined or modified edible oil is contacted with the porous bodies at a temperature in the range 60 to 150 ℃, preferably 80 to 120 ℃, more preferably 90 to 110 ℃.

5. A method according to any one of claims 1 to 3, wherein the refined or modified edible oil is contacted with the porous bodies at a temperature in the range 40 to 120 ℃, preferably between 50 to 90 ℃.

6. A method according to any one of claims 1 to 3 wherein the refined or modified edible oil is contacted with the porous bodies at a temperature of less than 90 ℃.

7. A method according to any one of claims 1 to 3 wherein the refined or modified edible oil is contacted with the porous body at a temperature of less than 60 ℃.

8. A process according to any preceding claim, wherein the refined or modified edible oil comprises palm oil, soybean oil, canola or rapeseed oil, sunflower oil, palm kernel oil, cottonseed oil, peanut oil, corn germ or corn oil, olive oil, rice bran oil, cocoa butter, coconut oil, safflower oil, animal fats such as tallow, lard or fish oil, or mixtures thereof.

9. A process according to claim 8, wherein the refined or modified edible oil comprises palm oil.

10. A method according to any one of the preceding claims, wherein the refined or modified edible oil is further refined, such as deodorising or steam stripping, after having been contacted with the porous bodies.

11. The process according to claim 10, wherein the refined or modified edible oil is further refined by steam stripping by countercurrent membrane stripping after having been contacted with the porous body.

12. An apparatus for reducing the amount of 3-and 2-Monochloropropanediol (MCPD), 3-and 2-monochloropropanediol fatty acid esters, and glycidyl esters in a refined or modified edible oil, the apparatus comprising a reaction vessel comprising a fixed bed of greater than 1mm porous bodies comprising an acid catalyst comprising at least one of silica-alumina, and gamma alumina.

13. The apparatus of claim 12, wherein the acid catalyst comprises silica-alumina.

14. A system comprising the apparatus of claim 12 or 13, further comprising a second treatment unit arranged to receive refined or modified edible oil from the reaction vessel, wherein the second treatment unit is a refining unit, such as a deodorizer or a steam stripper, preferably a steam stripper, more preferably a countercurrent membrane stripper.

15. Use of a fixed bed of porous bodies for reducing the amount of 3-and 2-Monochloropropanediol (MCPD), 3-and 2-monochloropropanediol fatty acid esters, and glycidyl esters in refined or modified edible oils, wherein the porous bodies are greater than 1mm and comprise an acid catalyst comprising at least one of silica-alumina, alumina and gamma alumina.

16. Use of a fixed bed of porous body according to claim 15, wherein the acid catalyst comprises silica-alumina.

Technical Field

The present application relates to a method of treating edible oil, a system for treating edible oil, and use for treating edible oil comprising an epoxy conversion (epoxide conversion) catalyst.

Background

3-and 2-Monochloropropanediol (MCPD) and its fatty acid esters and Glycidyl Esters (GE) are contaminants in refined or modified edible oils that are of increasing concern due to their potential negative impact on human health. These contaminants are not present in the crude edible oil but are generated during the refining or modification process. Although the systems, methods, and uses of the present application are also effective for reducing the content of MCPD and its fatty acid esters in edible oils, the present application aims to reduce the content of glycidyl esters of the general structure (I),

wherein R is the hydrocarbon end of a fatty acid such as palmitic acid, stearic acid or oleic acid. GE is considered potentially carcinogenic when hydrolyzed under glycidol release. Glycidol is on the list of possible carcinogenic compounds of group 2A of IARC (international agency for research on cancer). It is desirable to minimize the GE content of the edible oil. For sensitive applications, such as baby food, the desired level of GE is below 1ppm, reported as glycidol. For very sensitive applications, or for the main reason that compounds detrimental to human health should not be added during food processing, it is desirable to keep the GE content below the current detection limit of about 0.1 ppm.

These contaminants are present in all refined or modified oils, but are particularly high in palm oil. GE is generated from partial glycerides (mono-and diglycerides) during the high temperature deodorization of edible oils, which is accelerated at deodorization temperatures higher than 230 ℃. Deodorization is a normal and necessary step of refining of edible oils, typically carried out at temperatures in the range of 230-. GE may also be generated during fat modification. In refined or modified edible oils, levels of GE of 20-30 ppm are not uncommon and levels can be much higher.

US 2013/0323394 a1 relates to a process for producing refined oils with a reduced content of 3-MCPD esters and/or glycidyl esters, characterized in comprising a bleaching step followed by a deodorisation step and comprising a mild final refining step, i.e. a final bleaching and/or deodorisation step carried out under conditions that limit the production of undesired substances.

US 2014/0148608 a1 discloses a method of reducing the content of glycidyl esters in edible oils. One method involves re-bleaching the oil.

It has thus been shown that the content of glycidyl esters can be reduced by re-bleaching the edible oil with conventional pulp bleaching methods, followed by separation of the bleaching earth from the oil on a filter, possibly followed by re-deodorization (generally at low temperatures and/or for short durations, without re-formation of glycidyl esters). However, this method involves high investment and operating costs (bleach, filter) and oil losses associated with spent bleaching earth. The oil loss is typically about 35% of the amount of bleaching earth used. If the GE content is reduced by re-bleaching with 0.2-0.5% by weight (relative to the oil flow) of bleaching earth, the oil loss will correspond to about 0.1-0.2%, which corresponds to a loss of 0.5-1 ton of oil per day in a 500 ton per day plant, or about $ 125,000 and 250,000 per year at 330 working days per year at a cost of $ 800 per ton of oil lost in bleaching.

Summary of The Invention

It is an object of the present invention to avoid the oil loss associated with suspended bleaching earths. It is another object of the present invention to eliminate the need for filters to remove suspended bleaching earth.

These objects of the present invention, as well as other objects which will become apparent to those skilled in the art upon a study of the following description, are achieved by a method of treating a refined or modified edible oil, wherein the refined or modified edible oil is contacted with a porous body comprising an epoxy conversion catalyst, the porous body having a size greater than 0.5mm, preferably greater than 1 mm.

The epoxy conversion catalyst functions as an acid catalyst and promotes the conversion of the epoxy bonds, for example, by hydrolysis of the epoxy bonds of glycidyl esters in the presence of an acid catalyst. Such hydrolysis results in the formation of monoacylglycerides. Monoacylglycerides are present in small amounts in all edible oils and do not pose toxicity problems. However, the preferred epoxy conversion catalysts do not contribute to a substantial extent to degradation of edible oils, such as by acid hydrolysis of triacylglycerol ester linkages, resulting in the formation of diacylglycerides and fatty acids. The preferred epoxy conversion catalysts also do not promote other adverse side reactions that negatively affect, for example, taste or odor to a substantial extent. The epoxy conversion catalyst may be identified and evaluated using the procedures set forth in the examples below. As described below, the low amount of production of compounds which are undesirable from an organoleptic point of view when the oil is contacted with an acid catalyst enables subsequent deodorization or steam stripping under mild conditions.

The acid catalyst may comprise at least one of acid clay, activated clay, acid fuller's earth, activated fuller's earth, silica-alumina, alumina and gamma alumina. The epoxy conversion catalyst or acid catalyst may preferably comprise at least one of silica-alumina, alumina and gamma alumina. The epoxy conversion catalyst or acid catalyst may more preferably comprise silica-alumina.

It has been surprisingly found that the sensory properties of the refined or modified edible oil are better after contacting the oil with an epoxy conversion catalyst or acid catalyst comprised of a silica-alumina or gamma alumina material than when contacting the oil with an acid catalyst comprised of a clay/earth material. The porous bodies may be free of clay and bleaching earth.

Silicon oxide (SiO) of epoxy conversion catalyst or acid catalyst₂) With alumina (Al)₂O₃) The ratio of (d) may be in the range of 0.1 to 10, preferably 0.5 to 5, more preferably 0.5 to 2. At such ratios, the catalyst may have a favorable catalytically active acidity.

The size of the porous body is greater than 0.5mm, preferably in the range of 0.5 to 10mm, more preferably greater than 1mm, preferably in the range of 1 to 5 mm. Herein, "dimension" may be considered as the longest outer dimension of such a porous body. The porous bodies preferably comprise more than 75% by weight of porous bodies having the indicated dimensions, more preferably more than 95% by weight. A porous body smaller in size than indicated may cause a pressure drop that eventually results in plugging of the container in which the refined or modified edible oil is in contact with the porous body. Dimensions larger than the indicated porous body may render the inner surface of the porous body more difficult to access.

Others have previously observed that intraparticle diffusion in the pores plays a significant adverse role in adsorption and reaction phenomena on bleaching clays that already have a very small particle size of the order of 20 to 40 microns. It is therefore surprising that the content of glycidyl esters can be effectively reduced with objects having a size of, for example, more than 0.5mm (corresponding to 500 μm).

The pore volume of the porous body may be in the range of 0.1 to 2cm³In the range of/g, preferably from 0.5 to 1cm³G, more preferably 0.5 to 0.75cm³(ii) in terms of/g. Of porous bodies>250 Å pore volume% may be in the range of 5% to 50%, preferably 10% to 30%, more preferably 20% to 30%, the porous body may have a mesopore peak in the range of 10 to 100 Å, preferably 20 to 80 Å, more preferably 20 to 40 Å the specific surface area of the porous body may be in the range of 25 to 800m²In the range of/g, preferably from 100 to 500m²/g。

The porous body may be a shaped body. In this context, a "shaped body" may be considered as an object prepared by agglomerating smaller particles. In general, shaped bodies can be prepared by: compacting or densifying particles of a material comprising or consisting of an epoxy conversion catalyst, optionally mixed with another component, such as a binder or a liquid, followed by extrusion, pressing or pelletizing to form a shaped body. The shaped body can then be heat treated, for example by drying or calcining. The shaped bodies may be pellets, extrudates, tablets or granules.

The porous body or the shaped body may have a regular shape or an irregular shape or a mixture thereof. Such shapes include cylinders, spheres, rings, trilobes, and quadralobes.

The refined or modified edible oil may be contacted with the porous body at a temperature as low as 40 ℃ and, depending on the type of refined or modified edible oil, at a reaction temperature in the range between 40 ℃ and 150 ℃. This includes temperature ranges such as temperatures between 60 to 150 ℃, 80 to 120 ℃, 90 to 110 ℃, or such as temperatures between 40-60 ℃, 40-70 ℃, 40-80 ℃, 40-90 ℃, 40-100 ℃, 40-110 ℃, 40-120 ℃, 40-150 ℃. Other temperature ranges include temperatures between 50-60 deg.C, 50-70 deg.C, 50-80 deg.C, 50-90 deg.C, 50-100 deg.C, 50-110 deg.C, 50-120 deg.C, 50-150 deg.C, or temperatures between 60-70 deg.C, 60-80 deg.C, 60-90 deg.C, 60-100 deg.C, 60-110 deg.C, 60-120 deg.C, 60-160 deg.C. Even other temperature ranges include temperatures between 70-80 deg.C, 70-90 deg.C, 70-100 deg.C, 70-110 deg.C, 70-120 deg.C, 70-170 deg.C, even other temperature ranges include temperatures between 80-90 deg.C, 80-100 deg.C, 80-110 deg.C, 80-120 deg.C, 80-180 deg.C. The lower reaction temperature helps to reduce the glycidyl ester content of the edible oil to acceptable levels while also reducing the formation of compounds which are undesirable from an organoleptic point of view. The refined or modified edible oil may be contacted with the porous body at a reaction temperature of less than 150 ℃, less than 120 ℃, less than 110 ℃, preferably less than 100 ℃, more preferably less than 90 ℃, less than 80 ℃ or even less than 70 ℃.

For the purposes of the present invention, the glycidyl ester content was analyzed according to the AOCS (American Petroleum chemists' Association) legal method Cd29b-13,2015 revision. The process reports the glycidyl ester content as glycidol in mg/kg oil, i.e. parts per million by weight, abbreviated herein as ppm. The refined or modified edible oil to be contacted with the porous bodies may comprise glycidyl esters. The refined or modified edible oil to be contacted with the porous bodies may have a glycidyl ester content in the range of 1 to 50ppm, reported as glycidol, preferably 5 to 40ppm, more preferably 20 to 30 ppm. The process described above may result in a reduction of the glycidyl ester content of the refined or modified edible oil. The glycidyl ester content (reported as glycidol) of the refined or modified edible oil may be below 2ppm, preferably below 1ppm, more preferably below 0.5ppm, most preferably below 0.1ppm after having been contacted with the porous bodies.

The refined or modified edible oil can be selected from various edible oils and fats. The edible oil may comprise palm oil, soybean oil, canola or rapeseed oil, sunflower oil, palm kernel oil, cottonseed oil, peanut oil, corn germ or corn oil, olive oil, rice bran oil, cocoa butter, coconut oil, safflower oil, animal fats (e.g., tallow, lard or fish oil), or mixtures thereof. The edible oil may preferably comprise palm oil.

The edible oil is refined, e.g. deodorized or bleached, or modified, e.g. fractionated, hydrogenated, or modified, e.g. transesterified, before being contacted with the porous body. The refined or modified edible oil may typically preferably be deodorized at a temperature above 230 ℃, more preferably in the range of 230 to 265 ℃, prior to contacting with the porous bodies. In addition, the edible oil may be chemically treated with acid and/or caustic and bleached prior to deodorization or modification.

The refined or modified edible oil may, after having been contacted with the porous bodies, be further refined, for example deodorised or steam stripped, preferably steam stripped, more preferably steam stripped by countercurrent membrane stripping. Thus, steam stripping may serve as the final polishing step. In particular, deodorization or steam stripping can remove volatiles such as free fatty acids, odor and taste components. The deodorization or steam stripping is preferably carried out under mild conditions, i.e. for a short time or at low temperature, so as to reduce the reformation of glycidyl esters during deodorization or steam stripping. Thus, the deodorization is preferably carried out at a temperature in the range of 130 to 230 ℃ (preferably 180 to 220 ℃) and/or over a retention time in the range of 2 to 30 minutes (preferably 2 to 10 minutes). Even more preferably steam stripping is carried out by countercurrent thin film stripping at a temperature in the range of 180 to 220 ℃ over a retention time of 2 to 10 minutes. In particular, the low amount of production of undesirable compounds from an organoleptic point of view enables deodorization or steam stripping under mild conditions. The deodorization can also be carried out at conventional temperatures in the range from 230 to 265 ℃.

After such further refining, the glycidyl ester content (reported as glycidol) of the refined or modified edible oil may be below 2ppm, preferably below 1ppm, more preferably below 0.5ppm, most preferably below 0.1 ppm.

The refined or modified edible oil may be modified, for example fractionated, hydrogenated or transesterified, after having been contacted with the porous bodies and optionally having been further refined.

The above object is also achieved by a fixed bed apparatus for treating refined or modified edible oils. The apparatus comprises a reaction vessel or reactor comprising a fixed bed of porous bodies comprising an acid catalyst, the porous bodies having a size of greater than 0.5mm, preferably in the range of from 0.5 to 10mm, even more preferably in the range of from 1 to 5 mm. Fixed bed reactors are known forms of reactors and comprise a fixed bed (immobilized or fixed bed) of catalyst.

The above object is also achieved by a system for treating refined or modified edible oils, the system comprising: a first treatment unit, such as a deodorizer, crystallizer, hydrogenation reactor, or transesterification reactor; and a fixed bed reaction vessel arranged to receive the refined or modified edible oil from the first treatment unit, wherein the fixed bed reaction vessel comprises a fixed bed of porous bodies comprising an epoxy conversion catalyst or an acid catalyst, the porous bodies having a size greater than 0.5mm, preferably in the range of from 0.5 to 10mm, more preferably greater than 1mm, most preferably in the range of from 1 to 5 mm. Details regarding the edible oil, the porous body, and the epoxy conversion catalyst or acid catalyst, etc., can be obtained from the above-described method of treating the edible oil.

In particular, the porous body may be a shaped body, such as a pellet, extrudate, tablet or granule.

The system may further comprise a second treatment unit arranged to receive the edible oil from the reaction vessel, wherein the second treatment unit is a refining unit, such as a deodorizer or a steam stripper, preferably a steam stripper, more preferably a countercurrent membrane stripper.

The above object is also achieved by the use of a porous body comprising an epoxy conversion catalyst, the size of the porous body being larger than 0.5mm, preferably in the range of 0.5 to 10mm, more preferably larger than 1mm, most preferably in the range of 1 to 5mm, for the treatment of refined or modified edible oils. Details of the porous body, the epoxy conversion catalyst or the acid catalyst, and the refined or modified edible oil and the like can be obtained from the above-described method of treating the refined or modified edible oil.

Brief Description of Drawings

Figure 1 shows a system according to the invention at the end of a deodorisation section.

Figure 2 shows a system according to the invention integrated in a deep deodorisation section.

Detailed description of the preferred embodiments

In fig. 1, the edible oil from the bleaching section (not shown) is passed to a deodorisation section 10. The deodorized edible oil containing elevated levels of glycidyl esters leaves the deodorization section 10 and is passed via a heat exchanger 20 and a pre-filter 30 to a glycidyl ester conversion reactor 40. The edible oil containing a reduced level of glycidyl esters leaves the glycidyl ester conversion reactor 40 and is reheated via a post filter 50 to a suitable deodorization temperature (not shown) and passed via a post stripper 60 to heat exchange economizer (not shown), finally cooled (not shown) and stored or packaged (not shown). Downstream of the heat recovery step (not shown) of the deodorisation section 10, the temperature of the oil from the deodorisation section will typically be in the range of 120 to 140 ℃. During or just after such a heat recovery step, it is common practice to add about 20ppm of citric acid to the oil, for example by means of an aqueous solution 70 of citric acid of 100ppm to 20% by weight, in order to chelate the metal traces and improve the stability of the oil during storage. The temperature of the water/oil mixture is adjusted in an economizer (not shown) and heat exchanger 20 to an optimum reaction temperature in the range of 60 to 150 c before entering the glycidyl ester conversion reactor 40. The glycidyl ester conversion reactor 40 comprises a fixed bed 41 of porous bodies containing an epoxy conversion catalyst. The oil is gently steam stripped in the post stripper 60, steam 80 is provided to the stripper 60, and the off-gas is carried from the stripper to a scrubber (not shown) and a vacuum system (not shown). In general, the pumps required for fluid transport are not shown.

In fig. 2, the edible oil from the bleaching section (not shown) is passed through a deep deodorisation section 110. The deep deodorisation section 110 comprises a deodoriser or pre-stripper 111 followed by a chiller 112 and a holding section 113. The oil is deodorized or pre-stripped in a deodorizer or pre-stripper 111, steam (not shown) is provided to the deodorizer or pre-stripper 111, and off-gases are brought therefrom to a scrubber (not shown) and a vacuum system (not shown). The edible oil leaving the retention zone 113 is passed to the glycidyl ester conversion reactor 140 via heat exchanger 120. The glycidyl ester conversion reactor 140 comprises a fixed bed of porous bodies comprising an epoxy conversion catalyst. The heat exchanger 120 provides the option of adjusting the temperature of the oil entering the glycidyl ester conversion reactor 140. An additional small amount of water 190 is added to the oil to drive the hydrolysis of the glycidyl epoxide to high conversion levels. The edible oil leaving the glycidyl ester conversion reactor 140 is brought to post-stripping temperature in reheater 195 and then passed to final cooling (not shown) via post-stripper 114, heat recovery section 115 and post-filter 116 of deep deodorization section 110 and stored or packaged (not shown). Post-stripper 114 removes volatiles, such as free fatty acids, as well as odor and flavor components from the edible oil. As shown, the glycidyl ester conversion reactor 140 and its fittings can be conveniently placed between the retention zone 113 and the post stripper 114 of the deep deodorisation section 110. In general, the pumps required for fluid transport are not shown.