Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/001—Refining fats or fatty oils by a combination of two or more of the means hereafter
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/008—Refining fats or fatty oils by filtration, e.g. including ultra filtration, dialysis
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/10—Refining fats or fatty oils by adsorption

Definitions

• the invention relates to the refining of vegetable oils, in particular a method for reducing the 3-monochloropropane-1,2-diol content (hereinafter: 3-MCPD content) in vegetable oils.
• bleaching earths are used to remove cloudiness, discoloration and also to remove oxidation accelerators. Adsorptive cleaning can significantly improve the taste, color and storage stability of the oils and fats.
• Different classes of bleaching earth are used for cleaning.
• NABE Natural Active Bleaching Earth
• the third class of bleaching earth represents a compromise between low manufacturing costs and acceptable activity.
• SMBE Surface Modified Bleaching Earth
• a naturally active raw clay is treated with small amounts of acid and thus an "in situ activation" is achieved.
• raw clays containing attapulgite and hormite have proven useful for this process. These have a very high specific surface area for natural raw clays of approx. 100 to 180 m 2 / g and a pore volume of approx. 0.2 to 0.35 ml / g.
• salts formed during acid activation or unreacted components of the acid are not washed out, they remain on the product and are at least partially also deposited in the pores.
• these acid-activated bleaching earths usually do not achieve the same efficiency as is achieved by highly active bleaching earths (HPBE), which are produced by dealuminating with acid.
• HPBE highly active bleaching earths
• the simple manufacturing process enables comparatively inexpensive production, with the particular advantage that there is no acidic waste water.
• a fourth variant of bleaching earth is DMBE (Dry Modified Bleaching Earth).
• SMBE Manufacturing Modified Bleaching Earth
• the raw clay is generally treated with an aqueous solution of the acid.
• a solid acid is used for activation, usually citric acid, and the pure acid is ground together with the raw clay.
• the oil is first degassed and dried after pressing in order to remove dissolved oxygen, for example. Mucilages, in particular phospholipids, are then removed.
• phosphoric acid is added to the dried and degassed oil and the mixture is stirred at about 95 ° C. and normal pressure (ambient pressure) for about 15 to 20 minutes.
• further water is added at the end of the treatment, for example in a proportion of 0.2% by weight.
• the lecithin phase is separated off, for example by centrifugation.
• the subsequent bleaching of the degummed oil comprises two stages, wet bleaching and vacuum bleaching.
• 0.1 to 0.5% by weight of water is added to the degummed oil and, after the oil has been heated to 95 ° C., 0.3 to 3% by weight of bleaching earth is added.
• the mixture is then stirred at normal pressure (ambient pressure) for about 20 minutes.
• a vacuum is then applied (for example 100 mbar) and the oil is stirred at 95 ° C. for a further 30 minutes.
• the used bleaching earth is separated off, for example by filtering the mixture through a suction filter covered with a paper filter.
• the oil After bleaching, the oil is deodorized. To do this, superheated steam, which has an outlet temperature of around 240 ° C and higher, is passed through the oil in order to remove free fatty acids and unpleasant taste and odor substances.
• the deodorization is carried out in vacuo at a pressure in the range of less than 5 mbar, preferably 1 to 3 mbar.
• the oil After refining, the oil should meet certain requirements in terms of color, taste and shelf life, for example. Depending on the variety, the oil should be light to dark yellow in color. A yardstick for this is the Lovibond color number red, which should be as low as possible. In order to increase the shelf life, the oil should have a very low iron or phosphorus content. Furthermore, the oil should be as insensitive as possible to oxidation in order to prevent the development of a rancid odor and off-taste.
• undesirable accompanying substances can also be produced which, if consumed by humans, can have a harmful effect on health.
• 3-monochloropropane-1,2-diol can arise in the production of food, e.g. in the production of soy sauce, in baking and toasting, but also in the refining of vegetable oils and fats.
• 3-MCPD has been shown to be carcinogenic in animal experiments. In addition, its mutagenicity could be demonstrated in vitro, but not in vivo. There is also evidence that 3-MCPD affects the fertility of mammals.
• 3-MCPD can be contained in food both in free or in bound form, for example in the form of an ester.
• 3-MCPD was found in various fats and oils. The concentration in vegetable fats and oils can range from several hundred to several thousand ppb, each calculated as free 3-MCPD.
• the mechanism by which 3-MCPD is formed during fat and oil refining is not yet fully understood. In model studies, however, it has been shown that chloride ions, glycerine and mono-, di- and triglycerides are potential starting materials for the formation of 3-MCPD.
• EP 2361298 discloses that a modified degumming in combination with a selectively selected bleaching earth could significantly reduce the 3-MCPD content in the palm oil raffinate compared to the standard method of the prior art.
• EP 2361298 describes a method for reducing the 3-MCPD content in vegetable oils.
• EP 2361298 provides that water is added to the crude oil for degumming and degumming is carried out without the addition of acid at a temperature of less than 70 ° C, the degummed oil is heated to a temperature in the range from 80 to 110 ° C and closed bleaching earth is added to the heated degummed oil in an amount of more than 1.5% by weight, and the bleaching is carried out at a temperature in the range from 80 to 100 ° C. The bleaching earth is always added after degumming.
• EP 2738243 proposes a two-stage bleaching process to reduce the 3-MCPD content in vegetable oils, with an alkaline clay being used in the first bleaching step and an acidic clay in the second bleaching step following deodorization.
• EP 3321348 suggests a two-stage bleaching process to reduce the 3-MCPD content in vegetable oils, in which, after a degumming step, bleaching takes place for the first time using an activated bleaching earth at reduced pressure, and after a deodorization step, a second bleaching takes place using activated bleaching earth at reduced pressure.
• a similar solution to reducing 3-MCPD levels in vegetable oils is off WO 2012/107230 known: a two-stage bleaching - once before and once after a deodorization step - is proposed here too. After the second bleaching, another deodorization takes place.
• the first bleaching is preferably carried out after an optional degumming.
• WO2017 / 164728 describes a process for the production of heat-stable oils or fats intended for consumption.
• an oxidized crude glyceride oil is brought into contact with porous adsorbent particles before a degumming step and the oil after degumming with a bleaching material, including bleaching earth, bleached.
• porous adsorbent particles WO 2017/164728 porous zeolites, carbon, aluminophosphates, precipitated or fumed silica, silica gel and the like.
• the object of the invention is to enable a further significant reduction in the 3-MCPD values in the raffinate.
• the invention relates to a method according to claim 1.
• Advantageous embodiments of the invention are the subject matter of dependent claims 2 to 11.
• the invention further relates to a refined vegetable oil with a reduced 3-monochloropropane-1,2-diol content according to claim 12.
• An advantageous embodiment is the subject matter of dependent claim 13.
• the present invention relates to a method for reducing the 3-monochloropropane-1,2-diol content in vegetable oils.
• a crude vegetable oil is mixed with a bleaching earth and pre-bleached so that a pre-bleached vegetable oil is obtained.
• the pre-bleached vegetable oil is subsequently degummed, so that a degummed vegetable oil is obtained, which is then mixed with a bleaching earth and bleached, whereby a bleached vegetable oil is obtained.
• the bleaching earth is then separated from the bleached vegetable oil, so that a filter oil is obtained which is deodorized in a subsequent process step.
• a crude vegetable oil (“crude oil”) is first provided in the usual manner. This can be obtained, for example, in an oil mill by pressing.
• the crude oil can optionally also be degassed and dried in the usual way.
• the process according to the invention is suitable per se for the refining of any vegetable oils.
• the bleaching process according to the invention is particularly suitable for low-phosphorus oils which preferably have a phosphorus content of less than 100 ppm.
• the process according to the invention is preferably suitable for bleaching palm oil.
• the process according to the invention leads to a reduction in the 3-monochloropropane-1,2-diol content in the refined vegetable oil.
• the reduction is achieved in relation to a method in which a crude oil is bleached with otherwise identical parameters but without the pre-bleaching step according to the invention.
• suitable bleaching earths for the process are in particular types of bleaching earth that are neutral and chemically activated (e.g. activated with sulfuric acid) and belong to the group of HPBE or SMBE.
• Such bleaching earths can be referred to as neutral bleaching earths with low internal acidity.
• Particularly preferred bleaching earths of the type Tonsil® Supreme 118 FF, Optimum 218 FF, or Tonsil® 515 FF (all Clariant felt (Deutschland) GmbH) can be used.
• the reason for the preference for neutral bleaching earths is that neutral bleaching earths have a lower catalytic activity than acid activated bleaching earths. It has been found to be advantageous that the pre-bleaching step is only adsorptive, if possible, in order to avoid acid-catalyzed side reactions and to eliminate substances that can contribute to 3-MCPD formation.
• the oil is mixed with bleaching earth (according to the invention, the type Tonsil® Supreme 118 FF (Clariant discipline (Deutschland) GmbH) has proven to be an advantageous bleaching earth) at a dosage of 0.2 wt.% To 2.0 wt. %.
• This first bleaching is typically carried out for 10 minutes at a temperature of typically 60 ° C. and a pressure of typically 100 mbar with stirring.
• the addition of water is preferably avoided in the pre-bleaching, since 50% phosphoric acid (H 3 PO 4 ) is added in the subsequent step and should act in this concentration.
• 50% phosphoric acid (H 3 PO 4 ) is added in the subsequent step and should act in this concentration.
• the addition of water would result in a more complicated reaction procedure, in particular if intermediate filtration is desired, since an additional drying step is then required beforehand in order to enable proper filtration.
• the amount of bleaching earth that is used for the pre-bleaching step is typically between 0.2-2.0, preferably 0.5 Wt% and 1.0 wt% based on the weight of the crude vegetable oil.
• a minimum bleaching earth content of 0.2% by weight has proven to be sufficient to reduce the 3-MCPD content.
• An increase in the bleaching earth content to more than 2.0% by weight - based on the fully raffinate - shows a further reduction in the 3-MCPD content.
• a bleaching earth content of 0.5% by weight is advantageous. up to 1% by weight, since the effect of the reduction no longer increases proportionally, especially in the direction of higher bleaching earth contents.
• the pre-bleaching is typically carried out at a temperature of 55 ° C to 75 ° C, preferably at a temperature of 60 ° C.
• essentially only the adsorptive property of the bleaching earth should be used in this step. Temperatures in the range from 55 ° C to 75 ° C are sufficient for this.
• the moisture contained in the fuller's earth can contribute to better adsorption in this temperature range. Lower temperatures are not advisable, especially when bleaching palm oil, because of the usual storage temperature for palm oil; higher temperatures can promote side reactions.
• the pre-bleaching is typically carried out at ambient pressure.
• the atmospheric pressure contributes to better adsorption, since the fuller's earth releases the bound water more slowly.
• the pre-bleaching is usually carried out for a period of 5 minutes to 20 minutes, preferably for a period of 10 minutes.
• the degumming is preferably carried out in such a way that the crude oil is initially mixed with 50% phosphoric acid after the pre-bleaching and before the (actual) bleaching ("degumming 1").
• the amount of phosphoric acid is preferably less than 0.1% by weight, more preferably less than 0.05% by weight. According to one embodiment, the amount of phosphoric acid added is at least 0.02% by weight, according to a further embodiment at least 0.04% by weight. The percentages relate to the crude oil used.
• the degumming 1 is typically carried out at a temperature of 85.degree. C. to 105.degree. C., preferably at a temperature of 95.degree. In practice, the temperature of the degumming 1 is usually chosen so that it corresponds to the temperature of the bleaching.
• Degumming 1 is typically carried out at ambient pressure. At ambient pressure, better adsorption of the ingredients to be removed (P-lipids, metal ions) is achieved. Negative pressure removes the H 2 O required for optimal degumming too quickly, so it is preferred to work at ambient pressure.
• the degumming 1 is usually carried out for a period of 10 minutes to 20 minutes, preferably for a period of 15 minutes.
• water is added to the oil / acid mixture ("degumming 2").
• the amount of water is preferably less than 0.5% by weight, more preferably less than 0.3% by weight. According to one embodiment, the amount of water added is at least 0.1% by weight, according to a further embodiment at least 0.2% by weight. The percentages relate to the crude oil used.
• the degumming 2 is typically carried out at a temperature of 85.degree. C. to 105.degree. C., preferably at a temperature of 95.degree.
• the temperature of the degumming 2 is usually chosen so that it corresponds to the temperature of the bleaching (and thus also the temperature of the degumming 1).
• the degumming 2 is carried out analogously to degumming 1, typically at ambient pressure.
• the degumming 2 is usually carried out for a period of 5 minutes to 15 minutes, preferably for a period of 10 minutes.
• the lecithin phase can be separated from the degummed oil, for example by centrifuging, decanting or filtering. If the amount of water is less than 0.5% by weight, the water phase can be omitted. However, it is possible that the water phase is separated from the degummed oil even with smaller amounts of water. In particular with low-phosphorus oils such as palm oil, the lecithin phase can also be omitted.
• the bleaching after degumming is preferably carried out in at least two stages according to the invention, with wet bleaching first and then vacuum bleaching.
• the crude oil is first mixed with water.
• the amount of water is preferably in the range from 0.05 to 1.5% by weight, particularly preferably 0.1 to 1% by weight, ideally chosen around 0.5 wt .-%.
• the mixture is then mixed with bleaching earth at 80 to 100 ° C., particularly preferably 90 to 95 ° C., and stirred.
• the vacuum bleaching then takes place at an elevated temperature, particularly preferably at temperatures from 80 to 110 ° C., preferably at temperatures from 80 to 95 ° C. and a pressure in the range of about 100 mbar.
• the amount of fuller's earth used for the bleaching step after degumming is typically between 0.5 and 3.0% by weight, preferably between 1.1% and 2.0% by weight, based on weight on the weight of the degummed vegetable oil.
• the bleaching earth is separated from the bleached oil.
• Conventional methods can be used for this purpose.
• the bleaching earth can be allowed to sediment and the clear oil which is supernatant can be decanted off.
• the bleached oil is filtered, for example through a paper filter, so that a filter oil is obtained.
• the oil obtained after separating the bleaching earth from the bleached oil is referred to as filter oil, regardless of the method used to separate the bleaching earth.
• the filter oil is then deodorized.
• the usual methods are used under the usual conditions.
• superheated steam is passed through the oil, whereby a fully refined product is obtained.
• the superheated water vapor preferably has an outlet temperature in the range from 200 to 290 ° C.
• the deodorization is preferably carried out for a period of 30 minutes to 2 hours.
• the deodorization can be carried out in one stage, the outlet temperature of the superheated steam being kept essentially constant. However, it is also possible to carry out the deodorization in several stages, with the temperature of the superheated water vapor being changed during the deodorization.
• Superheated steam which has a temperature in the range from 250 to 290 ° C., is preferably initially introduced.
• This first step is preferably carried out for a period of 20 to 45 minutes.
• the outlet temperature of the steam is then lowered, preferably in a range from 200 to 240 ° C.
• the superheated steam is then preferably passed through the oil for an additional 30 to 120 minutes.
• the pre-bleached vegetable oil can be filtered after pre-bleaching and before degumming.
• the filtration is used to separate the bleaching earth used in the pre-bleaching.
• the filtration can be carried out with the means and methods known per se to the person skilled in the art, for example by using precoat filters or Frame filter presses.
• the optional filtration offers the advantage that the used bleaching earth from the 1st bleaching no longer comes into contact with the subsequently added acid.
• the intermediate filtration leads to an improvement in the red color number in the fully refined product.
• the crude vegetable oil can be degassed (and consequently dried) before the pre-bleaching step.
• the purpose of degassing is to remove the air contained in the oil before adding the bleaching earth in order to reduce the undesired formation of peroxides in the subsequent steps.
• the crude vegetable oil can be dried and degassed using means and methods known per se to the person skilled in the art, for example by applying a vacuum at an elevated temperature of 60 to 100.degree.
• the pre-bleaching before degumming and the bleaching after degumming of the vegetable oil is carried out in one embodiment of the invention with the same type of fuller's earth. This reduces the complexity of operating the oil refinery.
• Bleaching earths of the Tonsil® Supreme 118FF type have proven to be very suitable for the process according to the invention.
• highly active bleaching earth with a neutral reaction are generally suitable for the process according to the invention.
• the present invention also provides a refined vegetable oil (as indicated above) with a reduced 3-monochloropropane-1,2-diol content, which can be obtained by the process according to the invention.
• the vegetable oil is a palm oil.
• the Lovibond color number red was determined according to AOCS Cc 13b-45.
• t-BME t-butyl methyl ether
• ethyl acetate t-butyl methyl ether
• the fatty acids are then separated from the aqueous phase with hexane.
• the aqueous phase is mixed with phenylboronic acid and derivatized in a water bath at 80 ° C. for 20 minutes.
• the 3-MCPD derivative is extracted with n-hexane and measured by means of GC-MS (EH +, SIM mode).
• EH +, SIM mode A fused silica capillary coated with methyl silicone / phenyl silicone serves as the chromatography column.
• Example 1 bleaching of palm oil using the standard method
• the oil refined in this way had a Lovibond red color number ("CV red (51 ⁇ 4)") of 2.3 and had a 3-MCPD content of 2.4 ppm.
• Example 2 bleaching of palm oil with a modified standard process
• Crude palm oil was bleached analogously to Example 1 (for details see Table 2).
• Two different bleaching earths 1 and 2 were used after degumming and before deodorization. It was filtered between the two bleaching steps with different bleaching earths.
• Example 2 it was investigated whether "pre-bleaching" with a neutral bleaching earth 2 to remove the acid (H 3 PO 4 ) added to the oil for the purpose of degumming has a positive influence on 3-MCPD formation. Previous tests had shown that too high an acid dosage correlates with higher 3-MCPD values.
• the oil refined in this way had a Lovibond red color number ("CV red (51 ⁇ 4)") of 2.3 and had a 3-MCPD content of 2.8 ppm.
• Example 3 Influence of the bleaching earth dosage on the 3-MCPD content in the bleaching of palm oil with a modified standard method
• Example 4 Bleaching of palm oil using a method according to the invention
• Crude palm oil was bleached analogously to Example 1 (for details see Table 4).
• two bleaching steps were carried out, the first bleaching being carried out before degumming (so-called “pre-bleaching”) and the second bleaching after degumming and before deodorization.
• the oil refined in this way had a Lovibond red color number ("CV red (51 ⁇ 4)") of 2.2 and had a 3-MCPD content of 1.7 ppm.
• Example 5 Bleaching of palm oil with a method according to the invention
• the oil refined in this way had a Lovibond red color number ("CV red (51 ⁇ 4)") of 2.0 and had a 3-MCPD content of 1.7 ppm.
• the oil refined in this way had a Lovibond color number red ("CV red (51 ⁇ 4)") of 1.9 and had an even lower 3-MCPD content of 1.6 ppm.
• the method according to the invention enables the Lovibond red color number and the amount of 3-MCPD in the raffinate to be significantly improved compared to the standard method.
• An intermediate filtration after the pre-bleaching and before the degumming (method according to example 5) essentially only improves the Lovibond color number red compared to the method according to the invention without intermediate filtration (according to example 4).

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• Life Sciences & Earth Sciences (AREA)
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• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Fats And Perfumes (AREA)

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Citations (7)

• 2019
  • 2019-05-14 EP EP19174251.9A patent/EP3739027A1/fr not_active Withdrawn

Patent Citations (8)

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