FIELD OF THE INVENTION

[0001 ] The present invention relates to a novel process for removing glycidyl ester (GE) from a deodorized vegetable oil and obtaining a deodorized vegetable oil with a reduced content of GE and with good taste and oxidation stability.

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 of glycidyl esters (GE).

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

[0005] Processes exist to mitigate GE by removing in one or more of the refining steps the precursors of GE, resulting in a refined oil with reduced content of GE.

[0006] There is still a need in the industry to identify an efficient and effective method for removing the formed GE in deodorized oils and thus obtaining deodorized oils with low GE levels and with good taste and oxidation stability. The present invention provides such a process.

SUMMARY OF THE INVENTION

[0007] The present invention relates to a process for removing glycidyl esters (GE) from a deodorized vegetable oil, and the process comprises subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of an aqueous phase and performed at a temperature in a range of from 100 to 270°C.

[0008] The present invention further relates to the use of a hydrodynamic cavitation mixing, performed in the presence of an aqueous phase and at a temperature in a range of from 100 to 270 °C, for the removal of GE from deodorized vegetable oils.

DETAILED DESCRIPTION

[0009] The present invention relates to a process for removing GE from a deodorized oil, and the process comprises subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing, in the presence of an aqueous phase and performed at a temperature in a range of from 100 to 270°C.

Deodorized vegetable oil as starting material

[0010] The vegetable oil that is subjected to 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, com 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.

[0011] 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 deodorized vegetable 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.

[0012] The vegetable oil that is subjected to the process of the invention is a deodorized vegetable edible oil. In other words, the vegetable oil in the present process has been subjected to at least a deodorization step prior to the process of the present invention. Typically, a deodorized vegetable edible oil is obtained by means of 2 major types of refining processes, i.e. a chemical or a physical refining process. The chemical refining process typically comprises 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 typically comprises 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.

[0013] Preferably, the vegetable oil that is subjected to a hydrodynamic cavitation mixing of the process of the current invention is a physically refined oil (RBD oil).

[0014] 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 subsequently sent without any separation of the phosphatides to the bleaching step.

[0015] 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. [0016] 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

[0017] 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 subjected to the process of the invention, is comprising a degumming 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%.

[0022] The thus obtained bleached oil is subjected to a deodorization for preparing the deodorized vegetable oil that is subjected to the process of the invention.

[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. Such a deodorization step 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 the 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 subjected to the hydrodynamic cavitation mixing, 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 subjected to the hydrodynamic cavitation mixing, 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, or 2 mbar or less. [0028] The method for obtaining the deodorized vegetable oil, that is subjected to the hydrodynamic cavitation mixing, 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 bleached 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 (= starting material for the process of the present invention) that is subjected to the hydrodynamic cavitation mixing, 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.

[0030] Glycidyl esters are typically present as esters of fatty acids. Analytical methods used for determining glycidyl esters also detect 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 glycidyl esters include any free glycidol, that may be present in the oils.

[0031] 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.

[0032] 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 being subjected to the hydrodynamic cavitation mixing. Alternatively, two or more oils could be blended after the process of the present invention.

[0033] 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

The process according to the invention comprises subjecting the deodorized vegetable oil to a hydrodynamic cavitation mixing.

[0034] 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.

[0035] 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 resulting in cavitation to occur. [0036] 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. In one aspect of the invention, the hydrodynamic cavitation mixing 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. [0037] In one aspect of the invention the flow-through hydrodynamic cavitation mixing apparatus may comprise 2 or more, 4 or more, 6 or more, up to 15, up to 20 consecutive cavitation zones. A cavitation zone in the apparatus is each zone wherein the fluid is passing under pressure through a contraction. As a result, cavitation is induced in each of the consecutive cavitation zones.

[0038] The hydrodynamic cavitation mixing 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. The pressure at the entrance of the flow-through hydrodynamic cavitation mixing apparatus may be obtained by means of a high-pressure feed pump.

[0039] The hydrodynamic cavitation mixing 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.

[0040] The hydrodynamic cavitation mixing time 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 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.

[0041] In one aspect of the invention, the hydrodynamic cavitation mixing of the process may be repeated multiple times, up to 5 times, up to 3 times, or up to 2 times. Repetition of the hydrodynamic cavitation mixing may occur by recirculating the treated oil over the same flow-through hydrodynamic cavitation mixing apparatus, or by serial set-ups of these apparatuses, or by a combination of the two.

[0042] Subjecting the deodorized vegetable oil to the hydrodynamic cavitation mixing in the process according to the invention is performed in the presence of an aqueous phase. [0043] 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.

[0044] In one aspect of the invention, the deodorized vegetable oil is premixed with the aqueous phase prior to the hydrodynamic cavitation mixing of the process. The deodorized vegetable oil may be premixed with the aqueous phase 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 aqueous phase by means of a static mixer.

[0045] The deodorized vegetable oil may be premixed with the aqueous phase 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 phase may be injected into the flow-through hydrodynamic cavitation mixing apparatus.

[0046] Optionally, the obtained premix of the deodorized vegetable oil and the aqueous phase may react for a period up to 30 minutes, up to 15 minutes, up to 10 minutes, or up to 5 minutes, prior to the hydrodynamic cavitation mixing of the process.

[0047] In a specific aspect of the invention, the hydrodynamic cavitation mixing of the process is followed by a further residence time of at least 5 minutes, at least 15 minutes, or at least 30 minutes, 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.

[0048] In another specific aspect of the invention, the hydrodynamic cavitation mixing 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 prior to the following repetition. 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.

[0049] 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 the process, or a combination of two or more thereof.

Hydrodynamic mixing in the presence of water

[0050] In one aspect of the invention, the aqueous phase is water.

[0051] In one preferred aspect of the invention, the hydrodynamic cavitation mixing of the process 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.

[0052] In another preferred aspect of the invention, the hydrodynamic cavitation mixing of the process 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.

Hydrodynamic mixing in the presence of an aqueous solution of an acid agent

[0053] In an alternative aspect of the invention, the aqueous phase is an aqueous solution of an acid agent.

[0054] 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. 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. [0055] 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.

[0056] In one preferred aspect of the invention, the hydrodynamic cavitation mixing of the process 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.

[0057] In yet another preferred aspect of the invention, the hydrodynamic cavitation mixing of the process 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.

The GE-reduced deodorized vegetable oil obtained in the process

[0058] By subjecting a deodorized vegetable oil to the hydrodynamic cavitation mixing according to the process of the present invention, a deodorized vegetable oil is obtained that has a reduced content of GE versus the deodorized vegetable oil used as starting material. [0059] The process according to the invention may reduce the GE content in the deodorized vegetable oil to a content of 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). Subjecting the deodorized vegetable oil to the hydrodynamic cavitation mixing is reducing the GE content in the deodorized vegetable oil 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%.

[0060] 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 an aqueous phase and performed at a temperature in a range of from 100 to 270°C results in an increased breakdown of the formed GE present in the deodorized vegetable oil, whereas formation of off-flavours or oxidative instability of the oil is not or less increased.

[0061] The current process has demonstrated that the content of GE can be reduced and thus the final deodorized product has a reduced GE content. It was found that the process according to the invention is resulting in a deodorized vegetable oil that has a good sensorial quality and oxidation stability, as indicated before as well.

[0062] The sensorial quality of the GE-reduced deodorized vegetable oil can be expressed as an overall flavour quality score (taste), according to AOCS method Cg 2-83.By subjecting a deodorized vegetable oil to the hydrodynamic cavitation mixing according to the process of the present invention a GE-reduced deodorized vegetable oil is obtained with an overall flavour quality score 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).

[0063] The oxidative stability over time (its shelf life in terms of oxidative stability) of the GE-reduced deodorized vegetable oil is assessed by methods for measurement of the induction time which characterizes the resistance of the oil to oxidation. The induction time is expressed as Oil Stability Index (OSI). A suitable method can be the measurement using a Rancimat equipment (Metrohm) according to AOCS method Cdl2b-92. The process according to the invention results in a GE-reduced deodorized vegetable oil with an OSI value comparable to that of standard, commercially available RBD palm oil.

[0064] The flow-through hydrodynamic cavitation mixing apparatus has a small operational volume compared to equipment for bleaching, deodorization and/or stripping that is currently used for removal of GE and for further refining of the oil. This allows for an increased flexibility and increased efficiency of the process using hydrodynamic cavitation mixing.

[0065] The present invention further relates to the use of a hydrodynamic cavitation mixing performed in the presence of an aqueous phase and at a temperature in a range of from 100 to 270 °C for the removal of GE from deodorized vegetable oils.

[0066] As mentioned before, hydrodynamic cavitation, may have been used to mitigate the formation of GE by reducing the amount of precursors for GE formation. Still it is surprisingly found that hydrodynamic cavitation can be used to remove the formed GE in deodorized oils.

[0067] The use of the present invention is performed on a deodorized vegetable oil in the presence of an aqueous phase, wherein the aqueous phase is water or an aqueous solution of an acid agent.

[0068] The use of the hydrodynamic cavitation mixing according to the process of the invention may amongst others result in a reduction of GE that were already formed and present as such in the deodorized vegetable oil, while the oil has a good sensorial quality and oxidation stability.

[0069] 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 results in an increased breakdown of the formed GE molecules present in the deodorized vegetable oil, whereas formation of off- flavours or oxidative instability of the oil is not or less increased. The flow-through hydrodynamic cavitation mixing apparatus has a small operational volume compared to equipment for bleaching, deodorizing and/or stripping that is currently used for removal of GE and for further refining of the oil. This allows for an increased flexibility and efficiency of the process using hydrodynamic cavitation mixing.

[0070] It has been shown that amongst others, the present process is flexible when it comes to the sourcing of deodorized oils. It allows for the removal of GE that have been formed, while obtaining oils are edible and have a good sensorial quality and oxidation stability.

EXAMPLE

Measurement of GE

[0071] GE are measured according to Method DGF Standard Methods Section C (Fats)

C-VI 18(10). Test set-up

[0072] 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. The RBD palm oil has a GE content of about 10 ppm.

[0073] The RBD palm oil is mixed at a temperature of 75°C with 3,0 wt. % water by using an IKA T25 ultraturrax high shear mixer at 15000 rpm for 30 seconds.

[0074] The resulting mixture is heated in continuous flow to a temperature of 170°C at a pressure of 7000 kPa upstream the first hydrodynamic cavitation mixing step.

[0074] The heated mixture flows at 267 grams/minute through hydrodynamic cavitation mixing steps after which the mixture is being cooled to 75 °C and sampled or reprocessed multiple times through the same cavitation events. The collected samples are centrifugated for 5 minutes at 3350 ref to separate the water from the oil.

[0075] GE content of the treated RBD palm oil is measured.