FIELD OF THE INVENTION

[0001] The present invention relates to a novel process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil while avoiding interesterification and DAK formation.

BACKGROUND OF THE INVENTION

[0002] Crude oils, as extracted from their original source, are not suitable for human consumption due the presence of impurities - such as free fatty acids, phosphatides, metals and pigments - which may be harmful or may cause an undesirable colour, odour or taste. Crude oils are therefore refined before use. The refining process typically consists of three major steps: degumming, bleaching and deodorizing. An oil obtained after completion of the refining process (called a “refined oil” or more specifically a deodorized oil) is normally considered suitable for human consumption and may therefore be used in the production of any number of foods and beverages.

[0003] Unfortunately, it has now been found that the refining process itself contributes to the introduction, into the refined oil, of high levels monochloropropanediol esters (MCPDE) and glycidyl esters (GE). MCPDE includes 3-monochloropropane-l,2-diol fatty acid esters (3- MCPD esters), 2-chloro-l, 3-propanediol fatty acid esters (2-MCPD esters). MCPDE and GE are produced as a result of the oils being exposed to high temperatures during processing, in particular during deodorization.

[0004] A lot has been discussed and described in order to understand the mechanism of the formation, mitigation and reduction of MCPDE and GE.

Processes exist to mitigate MCPDE and/or GE by removing in one or more of the refining steps the precursors of MCPDE and/or GE, resulting in a refined oil with reduced content of MCPDE and/or GE.

[0005] WO2014/012759 describes a process for reducing MCPD compounds in refined plant oil for food.

[0006] W02012/031176 describes the elimination of organohalo and oxiranes species in carboxylic acid ester streams.

[0007] EP 3 321 348 further describes a process for refining vegetable oil with suppression of unwanted impurities.

[0008] There is still a need in the industry to identify an efficient and effective method for removing the formed MCPDE in deodorized oils and thus obtaining deodorized oils with low MCPDE levels, without modifying the triglyceride structure and/or without increasing content of process contaminants· The present invention provides such a process.

SUMMARY OF THE INVENTION

[0009] The present invention relates to a process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil and the process comprises a step a) of subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, and obtaining a base-treated oil.

[0010] The present invention further relates to the use of a hydrodynamic cavitation mixing for removing MCPDE from deodorized vegetable oils, wherein the hydrodynamic cavitation mixing is performed in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C.

DETAILED DESCRIPTION

[0011] The present invention relates to a process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil and the process comprises a step a) of subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, and obtaining a base-treated oil.

Deodorized vegetable oil as starting material [0012] The vegetable oil that is subjected to a hydrodynamic cavitation mixing in step a) of the process of the invention may be derived from one or more vegetable sources and may include oils and/or fats from a single origin or blends of two or more oils and/or fats from different sources or with different characteristics. They may be derived from standard oils or from specialty oils such as oils that have been subjected to fractionation and so on. Examples of suitable vegetable oils include: soybean oil, corn oil, cottonseed oil, palm oil, palm kernel oil, peanut oil, rapeseed oil, safflower oil, sunflower oil, sesame seed oil, rice bran oil, coconut oil, canola oil and any fractions or derivatives thereof, preferably palm oil.

Palm oil is encompassing palm oil, as well as palm oil fractions such as stearin and olein fractions (single as well as double fractionated, and palm mid fractions) and blends of palm oil and/or its fractions. Thus, in the context of the present invention, the vegetable deodorized oil is preferably palm oil, palm oil stearin, palm oil super stearin, palm oil olein, palm oil super olein, palm oil mid-fraction or blends of one or more thereof.

[0013] The vegetable oil that is subjected to a hydrodynamic cavitation mixing in step a) of the process of the invention is a deodorized vegetable oil. In other words, the vegetable oil in step a) of the present process has been subjected to at least a deodorization step prior to step a).

[0014] Typically, a deodorized vegetable edible oil is known to be obtained by means of 2 major types of refining processes, i.e. a chemical or a physical refining process. The chemical refining process may typically comprise the major steps of degumming, alkali refining, also called alkali neutralization, bleaching and deodorizing. The thus obtained deodorized oil is a chemically refined oil, also called “NBD” oil. Alternatively, the physical refining process may typically comprise the major steps of degumming, bleaching and deodorizing. A physically refining process is not comprising an alkali neutralization step as is present in the chemical refining process. The thus obtained deodorized oil is a physically refined oil, also called “RBD” oil.

[0015] Preferably, the vegetable oil used in step a) is a physically refined oil (RBD oil).

[0016] Thus for obtaining the deodorized oil, or the physically refined oil, a crude vegetable oil may be subjected to one or more degumming steps prior to the deodorization step. Any of a variety of degumming processes known in the art may be used. One such process (known as "water degumming") includes mixing water with the oil and separating the resulting mixture into an oil component and an oil-insoluble hydrated phosphatides component, sometimes referred to as "wet gum" or "wet lecithin". Alternatively, phosphatide content can be reduced (or further reduced) by other degumming processes, such as acid degumming (using citric or phosphoric acid for instance), enzymatic degumming (e.g., ENZYMAX from Lurgi) or chemical degumming (e.g., SUPERIUNI degumming from Unilever or TOP degumming from VandeMoortele/Dijkstra CS). Alternatively, phosphatide content can also be reduced (or further reduced) by means of acid conditioning, wherein the oil is treated with acid in a high shear mixer and is subsequently sent without any separation of the phosphatides to the bleaching step.

[0017] Beyond, the degumming step, the process for obtaining the deodorized oil may further comprise a bleaching step after the degumming step and prior to the deodorization step. The bleaching step in general is a process step whereby impurities are removed to improve the color and flavor of the oil. It is typically performed prior to deodorization. The nature of the bleaching step will depend, at least in part, on the nature and quality of the oil being bleached. Generally, a crude or partially refined oil will be mixed with a bleaching agent which combines, amongst others, with oxidation products, phosphatides, trace soaps, pigments and other compounds to enable their removal. The nature of the bleaching agent can be selected to match the nature of the crude or partially refined oil to yield a desirable bleached oil. Bleaching agents generally include natural or "activated" bleaching clays, also referred to as "bleaching earths", activated carbon and various silicates. Natural bleaching agent refers to non-activated bleaching agents. They occur in nature or they occur in nature and have been cleaned, dried, milled and/or packed ready for use. Activated bleaching agent refers to bleaching agents that have been chemically modified, for example by activation with acid or alkali, and/or bleaching agents that have been physically activated, for example by thermal treatment. Activation includes the increase of the surface in order to improve the bleaching efficiency.

[0018] Further, bleaching clays may be characterized based on their pH value. Typically, acid-activated clays have a pH value of 2.0 to 5.0. Neutral clays have a pH value of 5.5 to 9.0. [0019] A skilled person will be able to select a suitable bleaching agent from those that are commercially available based on the oil being refined and the desired end use of that oil. [0020] Therefore, in an aspect of the invention, the method for obtaining the deodorized vegetable oil that is used in step a) of the process, is comprising a degumming step and/or a bleaching step followed by a deodorization step.

[0021] The bleaching step takes place at a temperature of from 80 to 115°C, from 85 to 110°C, or from 90 to 105°C, in presence of neutral and/or natural bleaching earth in an amount of from 0.2 to 5.0%, from 0.5 to 3.0%, or from 0.7 to 1.5% based on amount of oil.

[0022] The thus obtained bleached oil is subjected to a deodorization for preparing the deodorized vegetable oil that is used in step a) of the present process.

[0023] Deodorization is a process whereby free fatty acids (FFAs) and other volatile impurities are removed by treating (or “stripping”) a crude or partially refined oil under vacuum with sparge steam, nitrogen or other gasses. The deodorization process and its many variations and manipulations are well known in the art and the deodorization step of the present invention may be based on a single variation or on multiple variations thereof.

[0024] For instance, deodorizers may be selected from any of a wide variety of commercially available systems (such as those sold by Krupp of Hamburg, Germany; De Smet Group, S.A. of Brussels, Belgium; Gianazza Technology s.r.l. of Legnano, Italy; Alfa Laval AB of Lund, Sweden; Crown Ironworks of the United States, or others) . The deodorizer may have several configurations, such as horizontal vessels or vertical tray-type deodorizers.

[0025] Deodorization is typically carried out at elevated temperatures and reduced pressure to better volatilize the FFAs and other impurities. The precise temperature and pressure may vary depending on the nature and quality of the oil being processed. The pressure, for instance, will preferably be no greater than 10 mm Hg but certain aspects of the invention may benefit from a pressure below or equal to 5 mm Hg, e.g. 1 - 4 mm Hg. The temperature in the deodorizer may be varied as desired to optimize the yield and quality of the deodorized oil. At higher temperatures, reactions which may degrade the quality of the oil will proceed more quickly. For example, at higher temperatures, cis-fatty acids may be converted into their less desirable trans form. Operating the deodorizer at lower temperatures may minimize the cis-to- trans conversion, but will generally take longer or require more stripping medium or lower pressure to remove the requisite percentage of volatile impurities. As such, deodorization is typically performed at a temperature of the oil in a range of 200 to 280°C, with temperatures of about 220-270°C being useful for many oils. Typically, deodorization is thus occurring in a deodorizer whereby volatile components such as FFAs and other unwanted volatile components that may cause off- flavors in the oil, are removed. Deodorization may also result in the thermal degradation of unwanted components.

[0026] In an aspect of the invention, in the method for obtaining the deodorized vegetable oil that is used in step a) of the present process, the vegetable edible oil is deodorized at a temperature of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C. The deodorization is taking place for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min.

[0027] In one more aspect of the invention, in the method for obtaining the deodorized vegetable oil that is used in step a) of the present process, the deodorization occurs in the presence of sparge steam in a range of from 0.50 to 2.50%, from 0.75 to 2.00%, from 1.00 to 1.75%, or from 1.25 to 1.50% and at an absolute pressure of 7 mbar or less, 5 mbar or less, 3 mbar or less, 2 mbar or less.

[0028] The method for obtaining the deodorized vegetable oil that is used in step a) of the present process is comprising the steps, in order, of: i) Bleaching the vegetable oil at a temperature of from 80 to 115°C, from 85 to 110°C, or from 90 to 105°C, with neutral and/or natural bleaching earth in an amount of from 0.2 to 5.0%, from 0.5 to 3.0%, or from 0.7 to 1.5%, and ii) Deodorizing the vegetable oil at a temperature of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, and for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min.

[0029] The deodorized vegetable oil used in step a) of the present process has a content of MCPDE that is 2.5 ppm or more, 3.0 ppm or more, 3.5 ppm or more, 4.0 ppm or more, 4.5 ppm or more, or even 5.0 ppm or more.

[0030] The deodorized vegetable oil used in step a) of the present process has a content of GE that is 1 ppm or more, 2 ppm or more, 3 ppm or more, 4 ppm or more, 5 ppm or more, 10 ppm or more, or even 15 ppm or more.

[0031] The term monochloropropanediol esters (MCPDE) refers to esters of MCPD and includes esters of 2-MCPD and 3-MCPD. The esters will typically be esters of the MCPD compounds with fatty acids. Glycidyl esters are also typically present as esters of fatty acids. Analytical methods used for determining MCPDE and glycidyl esters also detect free MCPD and free glycidol as being part of the content of ester compounds. However, the free compounds are typically present in the oils at very low levels. Therefore, the amounts of MCPDE and glycidyl esters include any free MCPD compounds and free glycidol, respectively, that may be present in the oils.

[0032] It is to be understood that an RBD oil is further inherently encompassing the standard quality parameters, that are commonly known, such as a low residual FFA content, a high oxidative stability, a light color, and a neutral odor and taste.

[0033] The method may also include - be preceded or followed by - one or more blending steps. It may be desirable, for instance, to blend oils of different types or from multiple sources. For example, a number of crude or partially refined oils could be blended before step a) of the present process. Alternatively, two or more oils could be blended after the process of the present invention.

[0034] The deodorized oil or RBD oil used as starting material for the process of the present invention can be sourced from anywhere. For instance, a crude vegetable oil may be subjected to steps of the previously described method, or the deodorized vegetable oil or RBD oil may be imported as such; thus demonstrating the flexibility of the process of the present invention.

Hydrodynamic cavitation mixing

[0035] The process according to the invention is comprising a step a) of subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases, and obtaining a base-treated oil

[0036] Cavitation is a known phenomenon in which rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities in places where the pressure is relatively low.

[0037] Hydrodynamic cavitation describes the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in local pressure. Hydrodynamic cavitation can be generated from liquid passing under pressure through a contraction (a narrowed space) such as an orifice plate, a nozzle, a Venturi nozzle, a valve or any design of a contraction allowing for cavitation to occur. As a result, an increase of kinetic energy is generated at the expense of pressure. Suitable equipment to generate the hydrodynamic cavitation mixing can be a flow-through hydrodynamic cavitation mixing apparatus. Alternatively, hydrodynamic cavitation mixing can also be generated in a rotating machinery such as a high-speed homogenizer with an adjustment of its rotating speed and geometry to generate the suitable hydrodynamic cavitation mixing. [0038] In one aspect of the invention, the hydrodynamic cavitation mixing in step a) of the process of the current invention is obtained by using a flow-through hydrodynamic cavitation mixing apparatus. Numerous flow-through hydrodynamic cavitation mixing apparatuses are known in the art.

[0039] In one aspect of the invention the flow-through hydrodynamic cavitation mixing apparatus may comprise 1 or more, 2 or more, 4 or more, 6 or more, up to 15, or up to 20 consecutive cavitation zones. A cavitation zone in the apparatus is a zone wherein the fluid is passing through a contraction under pressure. As a result, cavitation is induced in each of the consecutive cavitation zones.

[0040] The “one or more bases” is selected from carbonates, bicarbonates, hydroxides, alkoxides, carboxylates and mixtures of two or more thereof. Preferable the one or more bases is comprising potassium hydroxide, sodium hydroxide, sodium palmitate or potassium palmitate. More preferably the one or more bases is comprising potassium hydroxide or potassium palmitate. Alternatively, the treatment with the base includes the addition of one or more bases and in situ formation of one or more carboxylates. In particular the carboxylate can be formed by adding one or more bases to the oil comprising a certain amount of free fatty acids. The one or more bases may be added in step a) of the process as an aqueous solution.

[0041] The one or more bases is present in step a) of the process in a concentration of

0.003 to 1.471 mmol/kg, from 0.006 to 1.176 mmol/kg oil, or from 0.029 to 0.882 mmol/kg oil.

[0042] This can be further expressed such that, when the base is a hydroxide, it is present in a concentration of from 0.05 ppm to 25.0 ppm of molar equivalents of hydroxide ions, from 0.1 to 20.0 ppm, or from 0.5 to 15.0 ppm of molar equivalents of hydroxide ions. When the base is a palmitate, it is present in a concentration of from 0.8 ppm to 375.0 ppm, from 1.5 to 300.0 ppm, or from 7.5 to 225.0 ppm of molar equivalents of palmitate ions.

[0043] The hydrodynamic cavitation mixing is carried out in the presence of a fluid like, but not limited to, water. In one aspect of the invention, the hydrodynamic cavitation mixing in step a) of the process is performed in the presence of water and the water is present in an amount of max 2 wt%, max 1.5 wt%, or max 1.0 wt% and a minimum of 0.001 wt% based upon amount of oil.

[0044] The hydrodynamic cavitation mixing in step a) of the process is performed at a delta pressure in a range of from 1500 to 50000 kPa, from 2000 to 40000 kPa, or from 5000 to 35000 kPa. “delta pressure” is the pressure difference between the oil at the entrance of the flow-through hydrodynamic cavitation mixing apparatus and at the exit of the flow-through hydrodynamic cavitation mixing apparatus. The person skilled in the art is aware that the delta pressure that can be reached depends upon the scale and size of the cavitation apparatus. [0045] The pressure at the entrance of the flow-through hydrodynamic cavitation mixing apparatus may be obtained by means of a high-pressure feed pump.

[0046] The hydrodynamic cavitation mixing in step a) of the process is performed at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C.

[0047] The hydrodynamic cavitation mixing time in step a) of the process is in a range of less than 10 seconds, less than 8 seconds, less than 5 seconds, or less than 2 seconds. The hydrodynamic cavitation mixing time is defined as the residence time of the deodorized oil in the presence of the one or more bases in the flow-through hydrodynamic cavitation mixing apparatus. The hydrodynamic cavitation mixing time is calculated by the internal volume of the flow-through hydrodynamic cavitation mixing apparatus divided by the flow rate through the apparatus. It has to be understood that the hydrodynamic cavitation mixing time is small but is not zero.

[0048] In an aspect of the invention, the hydrodynamic cavitation mixing in step a) of the process may be repeated multiple times, up to 5 times, up to 3 times, or up to 2 times. Repetition of step a) may occur by recirculating the base-treated oil in the same flow-through hydrodynamic cavitation mixing apparatus, or by serial set-ups of these apparatuses, or by a combination of the two.

[0049] In one more specific aspect of the invention, the hydrodynamic cavitation mixing of step a) of the process is applied in the presence of a base in a concentration of from 0.003 to 0.412 mmol/kg of oil, such as 0.029 to 0.324 mmol/kg of oil, more preferably from 0.088 to 0.147 mmol/kg at a temperature in a range of from 160 to 270°C, preferably 170 to 260°C, more preferably 180 to 250°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds.

[0050] In yet another specific aspect of the invention, the hydrodynamic cavitation mixing of step a) of the process is applied in the presence of a base in a concentration of from 0.003 to 0. 412 mmol/kg of oil, such as 0.029 to 0.324 mmol/kg of oil, more preferably from 0.088 to 0.147 mmol/kg at a temperature in a range of from 100 to 180°C, preferably 105 to 170°C, more preferably 110 to 160°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds, whereby step a) is repeated up to 3 times, preferably up to 2 times.

[0051] In one aspect of the invention, the deodorized vegetable oil is premixed with the one or more bases prior to step a) of the process. The deodorized vegetable oil may be premixed with the one or more bases by means of any mixing device known in the art such as, but not limited to a static mixer, a high shear mixer. In a specific aspect of the invention, the deodorized vegetable oil is premixed with the one or more bases by means of a static mixer. [0052] The deodorized vegetable oil may be premixed with the one or more bases at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C. The obtained premix of the deodorized vegetable oil and the one or more bases may be injected into the flow-through hydrodynamic cavitation mixing apparatus. Optionally, the obtained premix of the deodorized vegetable oil and the one or more bases may react for a period up to 30 minutes, up to 15 minutes, up to 10 minutes, or up to 5 minutes, prior to step a) of the process.

[0053] The obtained base-treated oil is a deodorized vegetable oil that has been subjected to a hydrodynamic cavitation mixing in the presence of one or more bases. Consequently, the base-treated-oil has a reduced content of MCPDE versus the deodorized vegetable oil used as starting material.

[0054] In a specific aspect of the invention, the hydrodynamic cavitation mixing of step a) of the process is followed by a further mixing of the base-treated oil from step a) for a period of at least 5 minutes, at least 15 minutes, or at least 30 minutes. The further mixing may be performed at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C.

[0055] In another specific aspect of the invention, the hydrodynamic cavitation mixing in step a) of the process may be repeated multiple times, up to 5 times, up to 3 times, or up to 2 times, wherein between the repetitions there may be an intermediate residence time of at least 5 minutes, at least 10 minutes, or at least 15 minutes. It may be performed at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C.

[0056] In another specific aspect of the invention, the process may comprise the premixing time, the intermediate residence time, the further residence time of the hydrodynamic cavitation mixing of step a), or a combination of two or more thereof.

[0057] The process according to the invention, comprising the step a) of subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases, is reducing the MCPDE in the oil to a content of below 2.5 ppm, below 2.2 ppm, below 2.0, below 1.9 ppm, below 1.8 ppm, below 1.5 ppm, below 1.2 ppm, below 1.0 ppm, below 0.8 ppm, below 0.5 ppm, or below 0.3 ppm. This treatment may reduce the content of the MCPDE with more than 20%, more than 30%, more than 40%, more than 50%, more than 60%, more than 70%, more than 75%, more than 80%, more than 85%, or more than 90%.

[0058] Typically, there is a potential risk that by adding one or more bases to an oil, unwanted interesterification of the oil occurs, and it is resulting in a rearrangement of the fatty acids over the triglyceride backbone

[0059] Commonly known in the art is the alkali interesterification of lipids, or also called a chemical interesterification, which is a process for randomly distributing the fatty acids over the triglyceride structure. Typically, such an alkali interesterification will result in a degree of interesterification of about 100%. The process of the current invention is not an alkali interesterification. Surprisingly, the process according to the present invention allows to keep the degree of interesterification below 5%, below 4%, below 3%, below 0.7%, or below 0.3%. [0060] It was found that due to the hydrodynamic cavitation mixing, the treatment of the deodorized vegetable oil with one or more bases results in an increased breakdown of the MCPDE molecules, whereas the occurrence of an undesired interesterification reaction remains low.

[0061] In one aspect of the invention, the process comprising the step of subjecting a deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases is resulting in a base-treated deodorized vegetable oil having a content of MCPDE in a range of below 1.5 ppm, below 1.2 ppm, below 1.0 ppm, below 0.8 ppm, below 0.5 ppm, or below 0.3 ppm and interesterification degree of below 3.0%, below 2.9%, below 0.7%, or below 0.3%.

[0062] Additionally, it is known that during a known alkali (chemical) interesterification of lipids, also compounds such as dialkylketones (DAKs) are formed. The DAKs are ketones having two (C10-C24) straight chain alkyl groups, where the alkyl groups may be the same or different. In those known reactions, concentrations even higher than 140 ppm may be formed. By subjecting in the current invention the deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases, the formation of DAK is kept below 4.0 ppm, below 2.0 ppm, below 1.5 ppm, or even below 1.0 ppm.

[0063] It was found that due to the hydrodynamic cavitation mixing, the treatment of the deodorized vegetable oil with one or more bases results in an increased breakdown of the MCPDE molecules, whereas the occurrence of an undesired formation of DAK remains low. [0064] In an aspect of the invention, the process comprising the step of subjecting a deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases is resulting in a base-treated deodorized vegetable oil having a content of MCPDE in a range of below 1.5 ppm, below 1.2 ppm, below 1.0 ppm, below 0.8 ppm, below 0.5 ppm, or below 0.3 ppm and a DAK content of below 2.0 ppm, below 1.5 ppm, or below 1.0 ppm. [0065] In an aspect of the invention, the process comprising the step of subjecting a deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases is resulting in a base-treated deodorized vegetable oil having a content of MCPDE in a range of below 1.5 ppm, below 1.2 ppm, below 1.0 ppm, below 0.8 ppm, below 0.5 ppm, or below 0.3 ppm and interesterification degree of below 3.0%, below 2.9%, below 0.7%, or below 0.3%, and a DAK content of below 2.0 ppm, below 1.5 ppm, or below 1.0 ppm.

[0066] In reality, several existing processes that incorporate a treatment with a base, are sensitive to slight modifications of any of the parameters such as temperature, retention time, dosage of the base and the like. These processes end up with a significant modification of the triglyceride structure (and thus a significant degree of interesterification), and/or formation of dialkylketones (DAKs). In particular, the existing processes are less flexible than the current claimed process and the hydrodynamic cavitation mixing of the deodorized vegetable oil in the presence of one or more bases allows an easier control of the process because amongst others, it is a continuous process wherein the retention time of the oil is very short.

[0067] So far in existing processes a treatment of oil with a base involves the use of deodorizer equipment. Usually the base is added to the oil at or just before the deodorization step at temperatures above 120°C for a long residence time of generally more than 30 minutes. To obtain the vacuum, existing continuous deodorizers are built up of several trays. Sparge steam is forced through the layers of oil in the different trays to remove the volatiles. As a result, such continuous deodorizers have a large volume, which results in little flexibility for controlling the process parameters and as such avoiding the occurrence of side reactions such as interesterification and DAK formation. It was surprisingly found that by the process of the current invention wherein the deodorized vegetable oil is subjected to a hydrodynamic cavitation mixing in the presence of one or more bases, MCPDE is reduced while keeping a good to better control of the undesired side reactions. The flow-through hydrodynamic cavitation mixing apparatus has a small operation volume which makes it very flexible to control the process parameters.

[0068] It may be recognized that processes exist to mitigate the formation of MCPDE and such processes focus on the removal of precursors for MCPDE formation and are dedicated to one or more specific refining steps. There is no flexibility is the steps and a specific starting material is needed.

[0069] The current process has demonstrated that even if MCPDE is already formed, its content can be reduced and thus the final refined product has a reduced MCPDE content.

Further treatment step b)

[0070] In another aspect of the invention, the process is characterized in that it is comprising a further treatment step b), of the base-treated oil obtained from step a) or from the further mixing step subsequent to step a). The further treatment step b) includes contacting the base-treated oil with an adsorbent and/or an acid, or subjecting the base-treated oil to a second hydrodynamic cavitation mixing step in presence of an aqueous phase.

Contacting the base-treated oil with an adsorbent and/or an acid

[0071] In an aspect of the invention, the further treatment step b) includes contacting the base-treated oil with an adsorbent and/or an acid.

[0072] The adsorbent can be selected from bleaching agent, activated carbon, zeolite, exchange resin, silica and/or two or more combinations thereof. Examples of silica that can be employed in the present process include magnesium silicate, calcium silicate, aluminum silicate and combinations thereof. The activated carbon is preferably acidic activated carbon. The exchange resin is preferably a cation exchange resin. The bleaching agent can be neutral or activated bleaching agent. Activated bleaching agent refers to acid and/or physically activated (e.g. by thermal treatment). Activation includes the increase of the surface in order to improve the bleaching efficiency. Preferably an acid activated bleaching agent is applied.

[0073] The amount of adsorbent is in the range of from 0.3 to 4.0 wt% by weight of oil, in the range from 0.4 to 3.0 wt%, from 0.5 to 2.5 wt%, or from 0.6 to 2.0 wt%

[0074] The acid is provided as an aqueous solution. The acid may include phosphoric acid, sulfuric acid, ascorbic acid, citric acid, erythorbic acid, acetic acid, malic acid or combinations of two or more thereof. Preferably, the acid agent is selected from the group of phosphoric acid, citric acid, ascorbic acid, oxalic acid or combinations of two or more thereof; more preferably the acid is citric acid.

[0075] The amount of acid that is added to the base-treated oil is equivalent or 15% less than, 10% less than, 5% less than the molar amount of OH ions, or carboxylate (palmitate)- ions added during the treatment of the deodorized oil with a base. The acid may be added as an aqueous solution with a concentration of from 5 to 85%, from 20 to 70%, or from 30 to 60%. Typically, an 50% citric acid solution is used.

[0076] The temperature of the step b) is in the range of from 70 to 120°C, in the range of 80 to 110°C, or in the range of 85 to 100°C.

[0077] The contact time with the adsorbent and/or acid in step b) of the present process is in a range of from 15 to 60 minutes, from 20 to 50 minutes, or from 30 to 45 minutes.

[0078] At the end of the further treatment step b), the oil is separated from the adsorbent and/or soaps formed.

[0079] Without being bound by a theory, the further treatment step b) of the process of the present invention allows to reduce the content of glycidyl esters (GE). The content of glycidyl esters can be reduced to below LOQ (limit of quantification). Thus, the content of glycidyl esters can be reduced to below 0.10 ppm. Furthermore, the further treatment step b) allows to remove soap and/or further reduce the color of the base-treated oil.

[0080] The further treatment step b) of the process of the present invention may be a single step wherein the base-treated oil is contacted with one or more adsorbents and/or one or more acids. Alternatively, the further treatment step of the process may include multiple steps wherein the based treated oil is contacted with different adsorbents and/or acids in consecutive steps.

[0081] In an aspect of the invention, the process of the present invention includes a step b) of contacting the base-treated oil with an adsorbent, or with an adsorbent and an acid.

[0082] In a more specific aspect of the invention, the process of the present invention includes a step b) of contacting the base- treated oil with an adsorbent and an acid, and the step b) is comprising: bl) contacting the base-treated oil with an acid, b2) optionally removing the soap formed, and b3) contacting the base-treated oil with an acid-activated bleaching earth, wherein the acid in step bl) is selected from the group of phosphoric acid, sulfuric acid, ascorbic acid, citric acid, erythorbic acid, acetic acid, malic acid or combinations of two or more thereof; preferably the acid is selected from the group of phosphoric acid, citric acid, ascorbic acid, oxalic acid or combinations of two or more thereof; more preferably the acid is citric acid. [0086] In another aspect of the invention, the process of the present invention includes a step b) of contacting the base-treated oil with an adsorbent and an acid and the step b) is comprising: bl) contacting the base-treated oil with an acid, b2) removing the soap formed, and b3) contacting the base-treated oil with an acid-activated bleaching earth, wherein the acid in step bl) is selected from the group of phosphoric acid, sulfuric acid, ascorbic acid, citric acid, erythorbic acid, acetic acid, malic acid or combinations of two or more thereof; preferably the acid is selected from the group of phosphoric acid, citric acid, ascorbic acid, oxalic acid or combinations of two or more thereof; more preferably the acid is citric acid. [0087] The soap in step b2) of the process of the present invention may be removed by contacting the oil obtained from step bl) with an adsorbent, such as bleaching earth or silica. Preferably, silica is used to remove soaps in step b2) of the process.

[0088] Contacting the based-treated oil first with an acid and removing the soap formed, may allow that the acid- activated bleaching earth, that is subsequently added to the based- treated oil, reduces more effectively the content of GE and color. As a result, less acid- activated bleaching earth may be needed.

[0089] After the step b) of contacting the base-treated oil with an adsorbent and/or an acid, the color of the base-treated oil is low. In a more aspect of the invention, wherein the deodorized oil is palm oil or derived from palm oil, the base-treated palm based-oil after the further treatment step of the present process is characterized by a Lovibond red colour of 3.5R or less, 3R or less and/or a Lovibond yellow colour of 35Y or less, 30Y or less (measured in a 5¼ inch glass measuring cell according to AOCS method Ccl3e-92).

Subjecting the base-treated oil to a second hydrodynamic cavitation mixing step in presence of an aqueous phase

[0090] In an alternative aspect of the invention, the further treatment step b) includes subjecting the base-treated oil to a second hydrodynamic cavitation mixing in presence of an aqueous phase.

[0091] The “aqueous phase” is present in an amount of max 2.0 wt%, max 1.5 wt%, or max 1.0 wt and a minimum of 0.001 wt% based on the weight of the oil.

[0092] In an aspect of the invention, the aqueous phase is water.

[0093] In a preferred aspect of the invention, the second hydrodynamic cavitation mixing step is applied in the presence of water in a concentration in a range up to 2.0 wt%, up to 1.5 wt%, or up to 1.0 wt%, and minimum of 0.001 wt%, based on the weight of the oil, at a temperature in a range of from 160 to 270°C, preferably 170 to 260°C, more preferably 180 to 250°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds.

[0094] In another preferred aspect of the invention, the second hydrodynamic cavitation mixing step is applied in the presence of water in a concentration in a range up to 2.0 wt%, up to 1.5 wt%, or up to 1.0 wt% and minimum of 0.001 wt%, based on the weight of the oil, at a temperature in a range of from 100 to 180°C, preferably 105 to 170°C, more preferably 110 to 160°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds, whereby the hydrodynamic cavitation mixing is repeated up to 3 times, or preferably up to 2 times.

[0095] In an alternative aspect of the invention, the aqueous phase of the second hydrodynamic cavitation mixing step is an aqueous solution of an acid agent.Preferably, the acid agent is selected from the group of phosphoric acid, sulphuric acid, citric acid, ascorbic acid, oxalic acid, fumaric acid, aspartic acid, acetic acid, malic acid, erythorbic acid or combinations of two or more thereof. More preferably, the acid agent is selected from the group of phosphoric acid, citric acid, ascorbic acid, oxalic acid or combinations of two or more thereof. Preferably, the amount of acid agent on total weight of the oil is in a range of from 0.1 to 100.0 ppm, from 0.5 to 75.0 ppm, from 1.0 to 60.0 ppm, or from 2.0 to 40.0 ppm.

[0096] In a preferred aspect of the invention, the second hydrodynamic cavitation mixing step is applied in the presence of an aqueous solution comprising an acid agent and the acid agent is present in a concentration in a range of from 0.1 to 25 ppm, from 0.5 to 20.0 ppm, or from 1.0 to 15.0 ppm, based on total weight of the oil, at a temperature in a range of from 160 to 270°C, preferably 170 to 260°C, more preferably 180 to 250°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds.

[0097] In yet another preferred aspect of the invention, the second hydrodynamic cavitation mixing step is applied in the presence of an aqueous solution of an acid agent and the acid agent is present in a concentration in a range of from 2 to 100 ppm, from 10 to 80 ppm, from 15 to 60 ppm, or from 20 to 50 ppm on total weight of the oil, at a temperature in a range of from 100 to 180°C, preferably 105 to 170°C, more preferably 110 to 160°C, for a period of time in a range of less than 5 seconds, preferably less than 4 seconds, more preferably less than 2 seconds, whereby the hydrodynamic cavitation mixing is repeated up to 3 times, preferably up to 2 times.

[0098] In another aspect of the invention, the base-treated oil from step a) is premixed with the aqueous phase prior to the second hydrodynamic cavitation mixing step. The base- treated oil from step a) may be premixed with the aqueous solution by means of any mixing device known in the art such as, but not limited to a static mixer, a high shear mixer. In a specific aspect of the invention, the base-treated oil from step a) is premixed with the aqueous solution by means of a static mixer.

[0099] The base-treated oil from step a) may be premixed with the aqueous solution at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C. The obtained premix of the deodorized vegetable oil and the aqueous solution may be injected into the flow-through hydrodynamic cavitation mixing apparatus. Optionally, the obtained premix of the deodorized vegetable oil and the aqueous solution may react for a period up to 30 minutes, up to 15 minutes, up to 10 minutes, up to 5 minutes, prior to the second hydrodynamic cavitation mixing step in the presence of an aqueous phase. Obtained oil from further treatment step b)

[0100] The process according to the invention, comprising a step a) of subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, and further treating the base- treated oil from step a) in a further treatment step b) including contacting the base-treated oil with an adsorbent and/or an acid, or subjecting the base-treated oil to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, results in an oil with a reduced content of GE and a reduced content of MCPDE versus the deodorized vegetable oil that was used as starting material in step a).

[0101] The process comprising step a) and step b) is reducing MCPDE in the oil to a content of below 2.5 ppm, below 2.2 ppm, below 2.0, below 1.9 ppm, below 1.8 ppm, below 1.5 ppm, below 1.2 ppm, below 1.0 ppm, below 0.8 ppm, below 0.5 ppm, or below 0.3 ppm, and is reducing the content of GE in the oil to a content below 1.0 ppm, below 0.8 ppm, below 0.6 ppm, below 0.4 ppm, below 0.2 ppm, below 0.10 ppm, or even to below LOQ (limit of quantification).

Further processing step c)

[0102] In another aspect of the invention, the process is characterized in that it is comprising a further processing step c) carried out after step b) and wherein the further processing step c) is a fractionation step and/ or a further refining step.

[0103] In one aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil is characterized in that it comprises the following steps: a) Subjecting a deodorized vegetable oil to a hydrodynamic cavitation mixing in the presence of one or more bases and obtaining a base-treated oil, and, b) Contacting the base-treated oil from step a) with an adsorbent and/or an acid, or subjecting the base-treated oil from step a) to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, c) Treating the oil from step b) in a further processing step. [0106] In particular, the further processing step c) is a fractionation step of a deodorized base-treated palm oil. The fatty acid distribution in palm oil lends itself into fractionation and the production of multiple fractions of palm oil. Palm oil fractions may comprise palm olein, palm stearin and fractions further obtained through re- fractionation, either from the palm olein or palm stearin, such as palm mid-fraction, double fractionated palm olein, also called superolein, double fractionated stearin, also called superstearin, and even further fractions obtained through re-fractionation of palm-mid fraction. The presence of trisaturated and disaturated triglycerides in the palm oil facilitates the formation of fat crystals, in particular as the oil is chilled. On the contrary, when the position of the fatty acids of the triglycerides is changed or disrupted by interesterification, the fractionation is hampered and will be cumbersome. By applying the process of the present invention, the degree of interesterification is kept low and thus the fractionation is facilitated. Any suitable fractionation method can be applied. In fact, the process of the present invention is beneficial for any subsequent step where oil crystallization can be a determining factor.

[0107] More in particular, the present invention provides a process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil characterized in that it comprises the following steps: a) Subjecting a deodorized palm oil to a hydrodynamic cavitation mixing in the presence of one or more bases and obtaining a base-treated palm oil, and b) Contacting the base-treated oil from step a) with an adsorbent and/or an acid, or subjecting the base-treated oil from step a) to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, c) Treating the palm oil of step b) in a further processing step wherein the further processing step is a fractionation step, and d) Collecting separately the fractions obtained in step c).

[0108] In another aspect of the invention, the further processing step c) is a further refining step.

[0109] The “further refining step” in the present process is carried out at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C.

[0110] The “further refining step” in the present process may result in a further improvement of the taste. It may result in a refined vegetable oil having a reduced content of MCPDE, a reduced content of GE and a taste that is acceptable to good. The refined vegetable oil has a content of the MCPDE below 2.5 ppm, below 1.9 ppm, below 1.8 ppm, 1.5 ppm, below 1.2 ppm, below 1 ppm, or below 0.8 ppm. The GE content of the refined vegetable oil is below 1.0 ppm, below 0.7 ppm, below 0.5 ppm, below 0.3 ppm, below 0.1 ppm, or below LOQ (limit of quantification). The refined vegetable has an overall flavour quality score (taste), according to AOCS method Cg 2-83, in a range of from 7 to 10, or from 8 to 10 or even from 9 to 10 (with 10 being an excellent overall flavour quality score and 1 being the worst score).

[0111] The “further refining step” is carried out in a deodorizer, or preferably in an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray.

[0112] In a specific aspect, the “further refining step” is carried out in an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray. The refining ability of this refining equipment is obtained from the use of the stripping column and not more than one oil collection tray. It is to be understood that in order to operate the refining equipment, valves, pumps, heat exchangers (heating and/or cooling of the oil), and the like, are needed. An in-line heater may be used before the stripping column. The “not more than one” oil collection tray is a range covering “up to one” collection tray, and thus including also no collection tray.

[0113] The “oil refining equipment” is not containing retention trays. Retention trays, retention vessels, or compartments, also known as sections, are always present in standard deodorizer equipment known in the art, whether batch, continuous or semi-continuous deodorizer equipment. In each tray the oil is kept for a certain time at high temperature and steam is introduced into the oil.

[0114] It has been found that the height to diameter ratio of the stripping column of the oil refining equipment is from 0.1 to 10, from 0.5 to 5, or from 1.4 to 4.0.

[0115] The packing can be random packing or structured packing. Preferably the packing is a structured packing.

[0116] The term “structured packing” is well-known in the technical field and it refers to a range of specially designed materials for use in absorption and distillation columns. Structured packings typically consist of thin corrugated metal plates arranged in a way that force fluids to take complicated paths through the column and thereby creating a large surface, which can enhance the interaction between oil and stripping agent.

[0117] The packing in the equipment of the present invention is having a specific surface of from 100 to 750 m ² /m ³ , from 100 to 500 m ² /m ³ , or from 150 to 400 m ² /m ³ . Furthermore, the stripping column of the oil refining equipment has an oil loading of from 0.5 to 4.0 kg/m ² h surface of packing, from 0.6 to 3.5 kg/m ² h surface of packing, or from 0.8 to 3.3 kg/m ² h.

[0118] The “oil refining equipment” allows for a short residence (retention) time. In particular, a total residence time in the refining equipment, including not more than one collection tray, and including a pre-heating (using a heating device prior to passing the oil through the oil refining equipment), is not more than 20 minutes. More in particular, the process of the present invention allows a residence time in the packing of the stripping column of from 1 to 10 minutes. These short residence times are further beneficial to avoid further formation of the process contaminants· The stripping agent is steam or any other stripping gas, such as nitrogen gas. Preferably steam is used as stripping agent. The stripping column is operated at an absolute pressure of below 8 mbar.

[0119] In an aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil is characterized in that it comprises the following steps: a) Subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base-treated oil, and b) Contacting the base-treated oil from step a) with an adsorbent and /or acid, c) Treating the oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min. [0124] In a specific aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil is characterized in that it comprises the following: a) Subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base-treated oil, and b) Contacting the base-treated oil from step a) with an adsorbent and /or acid, c) Treating the oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, and wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min, and wherein the vegetable oil is palm oil, palm oil stearin, palm oil super stearin, palm oil olein, palm oil super olein, palm oil mid-fraction or blends of one or more thereof.

[0125] In another specific aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized palm oil is characterized in that it comprises the following: a) Subjecting the deodorized palm oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base- treated palm oil, and b) Contacting the base-treated palm oil from step a) with an adsorbent and / or acid, c) Treating the palm oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, and d) Treating the palm oil of step d) in a fractionation step, and e) Collecting separately the fractions obtained in step e), and wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min.

[0126] In an aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil is characterized in that it comprises the following steps: a) Subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base-treated oil, and b) Subjecting the base-treated oil from step a) to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, c) Treating the oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min.

[0127] In a specific aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized vegetable oil is characterized in that it comprises the following steps: a) Subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base-treated oil, and b) Subjecting the base-treated oil from step a) to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, c) Treating the oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, and wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min, and wherein the vegetable oil is palm oil, palm oil stearin, palm oil super stearin, palm oil olein, palm oil super olein, palm oil mid-fraction or blends of one or more thereof.

[0128] In another specific aspect of the invention, the process for removing monochloropropanediol esters (MCPDE) from a deodorized palm oil is characterized in that it comprises the following steps: a) Subjecting the deodorized palm oil to a hydrodynamic cavitation mixing, in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C, from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C, and obtaining a base- treated palm oil, and b) Subjecting the base-treated oil from step a) to a second hydrodynamic cavitation mixing step in the presence of an aqueous phase, c) Treating the palm oil of step b) in a further refining step carried out in a deodorizer or an oil refining equipment consisting of a stripping column with packing and not more than one oil collection tray and at a temperature below 220°C, below 215°C, below 210°C, below 200°C, below 190°C, from 130 to 210°C, or from 140 to 185°C, and d) Treating the palm oil of step d) in a fractionation step, and e) Collecting separately the fractions obtained in step e), and wherein the deodorized oil used in step a) is subjected prior to step a) to at least a deodorization step at a temperature in range of from 200 to 270°C, from 210 to 260°C, or from 220 to 250°C, for a period of time from 30 min to 240 min, from 45 min to 180 min, or from 60 min to 150 min.

[0129] The present invention further relates to the use of a hydrodynamic cavitation mixing for removing MCPDE from deodorized vegetable oils, wherein the hydrodynamic cavitation mixing is performed in the presence of one or more bases and at a temperature in a range of from 100°C to 270°C. [0130] In another aspect, the use of the present invention is performed at a temperature in a range of from 110°C to 260°C, from 120°C to 250°C, or from 130°C to 240°C.

[0131] The use of the hydrodynamic cavitation mixing is performed on a deodorized vegetable oil in the presence of one or more bases results in a reduction of MCPDE in the oil, while the occurrence of unwanted side reactions such as interesterification reaction and formation of DAK is limited. It is known that hydrodynamic cavitation mixing may initiate and/or accelerate chemical reactions and processes. Surprisingly it has been found that the hydrodynamic cavitation mixing of the deodorized vegetable oil in the presence of one or more bases results in an increased breakdown of the MCPDE molecules present in the deodorized vegetable oil, whereas the reaction speed of the unwanted side reactions is not or less increased. The flow-through hydrodynamic cavitation mixing apparatus has a small operational volume compared to the deodorizer equipment that is currently used in processes for removal of MCPDE in the presence of one or more bases. This allows for an increased flexibility of the process using hydrodynamic cavitation mixing for controlling the process parameters. Consequently, the increased flexibility allows to reduce more efficiently the occurrence of side reactions such as interesterification and DAK formation.

EXAMPLE

Analytical Methods

Measurement of DAK content

[0132] We recite here the key-points of the method used to analyze DAK content. Every detail of the method is made available in W02009/012982 on page 17 to 22.

Sample preparation:

• Saponification: 1ml sample (exact weight is recorded) is heated until it is fully melted. 10 ml 2N ethanolic KOH solution is added to the 1ml sample and heated for 20 minutes at 90°C in a closed container. The container is cooled to room temperature and 10 ml of water is added to dissolve the soaps. If necessary, the sample can be heated until the soaps are dissolved.

• Extraction of unsaponifiable: Subsequently 5 ml of petroleum ether is added to that solution and mixed several times with a shaker. The complete petroleum ether layer is transferred to a second container and the extraction is repeated twice. Petroleum ether phases of all extractions are collected.

• Washing of the extract: 10 ml of water/ethanol (1:1) solution is added to the collected petroleum ether phases and mixed several times with the aid of a shaker. The petroleum ether phase is collected and the washing step is repeated.

• Drying & dissolving: the washed petroleum ether layer is evaporated under a gentle flow of nitrogen. The dried residue is dissolved in 4ml of a toluene/hexane (1:1).

HPLC analysis:

The samples are analyzed on a HPLC system under the following conditions:

• Alltech Econosphere Silica HPLC column (150*4.6 mm, 3 pm) flow: 0.9 ml/min

• injection volume: 20 pi

• detector: Evaporative light scattering detector ELSD (drift-tube: 75°C; nebuliser: 1.75 SLPM (standard liters per minute nitrogen)

[0133] The mobile phase is a gradient hexane, ethylacetate and Toluene containing 2.5 ml/I formic acid): [0134] Amount of DAK is calculated by comparing it to a calibration curve of standard solutions of DAK.

Measurement of MCPDE

[0135] MCPDE are measured according to Method DGF Standard Methods Section C

(Fats) C-VI 18(10).

Test set-up

[0136] Crude palm oil is refined, bleached and deodorized according to standard conditions to obtain an RBD palm oil. More specifically, the deodorization is performed at a temperature of 245 °C during 3h at pressure of 5 mbar, using 1% of sparge steam per hour. [0137] The RBD palm oil has a 3-MCPD content of about 3 ppm.

[0138] The RBD palm oil is mixed at a temperature of 75°C with 0.67 wt. % of an aqueous KOH solution (0.053 M) by using an IKA T25 ultraturrax high shear mixer at 20000 rpm for 30 seconds

[0139] The resulting mixture is heated in continuous flow to a temperature of 170°C at a pressure of 6900 kPa upstream the first a hydrodynamic cavitation mixing step.

[0140] The heated mixture flows at 200 grams/minute through 3 hydrodynamic cavitation mixing steps after which the mixture is being inline-cooled to approximately 75 °C in order to sample or reprocess multiple times through the same cycle of inline-heating, hydrodynamic cavitation mixing step and inline-cooling. A base-treated RBD palm oil is obtained.

[0141] 3-MCPD content of the base-treated RBD palm oil is measured.