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
  • C11B3/10—Refining fats or fatty oils by adsorption
• • 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
  • C11B7/00—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils
  • C11B7/0008—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils by differences of solubilities, e.g. by extraction, by separation from a solution by means of anti-solvents
  • C11B7/005—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils by differences of solubilities, e.g. by extraction, by separation from a solution by means of anti-solvents in solvents used at superatmospheric pressures
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
  • A23C15/00—Butter; Butter preparations; Making thereof
  • A23C15/12—Butter preparations
  • A23C15/14—Butter powder; Butter oil, i.e. melted butter, e.g. ghee ; Anhydrous butter
  • A23C15/145—Removal of steroids, e.g. cholesterol or free acids; Fractionation of anhydrous milkfat by extraction with solvents other than solvent crystallisation or with supercritical gases or by distillation

Definitions

• This invention relates to the separation of sterols (and in particular cholesterol) from lipids, i.e. from naturally occurring fats or oils. It has particular though not sole application to the preparation of a low cholesterol or cholesterol free butter or tallow.
• the primary source of cholesterol in foodstuffs is lipid-containing food such as meat, either red or white, shell-fish, and dairy products such as butter or cheese.
• the lipid components of interest are those known as neutral lipids.
• This class of lipids contains: mono-, di- and tri-acylglycerides, collectively known as fat; free and esterified cholesterol, and other sterols; free fatty acids, fatty alcohols and wax esters.
• fat mono-, di- and tri-acylglycerides, collectively known as fat
• free and esterified cholesterol, and other sterols free fatty acids, fatty alcohols and wax esters.
• free fatty acids fatty alcohols and wax esters.
• fatty alcohols fatty alcohols and wax esters
• EP 0174848 in the name of New Zealand Dairy Research Institute, teaches a method of removing cholesterol from anhydrous milk fat at a temperature of 70 - 90° C, with the addition of active pulverised carbon, which is stirred into the heated fat for one hour, removed by filtration, and then the heated fat is treated again with pulverised carbon a number of times until the milk fat is cholesterol free or at least substantially free of cholesterol.
• active pulverised carbon which is stirred into the heated fat for one hour, removed by filtration, and then the heated fat is treated again with pulverised carbon a number of times until the milk fat is cholesterol free or at least substantially free of cholesterol.
• Such a treatment degrades the milk fat by heating, results in oxidation and unpleasant odours, requiring the subsequent use of a deodoriser and antioxidants, and degrades or removes the flavouring and colouring components of the milk fat.
• the milk fat thus requires additional treatment and addition of additives in order to endeavour to simulate its original colour and flavour.
• sterols and in particular cholesterol
• a high pressure liquid or sub or supercritical gas such as C0 2
• an adsorbant which is made up from or includes the oxygen containing salts of the basic metals such as the oxides, hydroxides, carbonates, sulphates, or the like.
• the invention provides a method of separating sterols from lipids, including: (a) dissolving the sterol/lipid mixture in a high pressure physiologically acceptable fluid (either as a high pressure liquid or as a high pressure sub or supercritical gas), and (b) contacting the high pressure fluid mixture with an adsorbant material which is made up from or includes the oxygen containing salts of. the basic metals such as the oxides, hydroxides, carbonates, sulphates, or the like, to selectively adsorb the sterols on the adsorbant material, and (c) removing the substantially sterol free lipids from the high pressure fluid.
• a high pressure physiologically acceptable fluid either as a high pressure liquid or as a high pressure sub or supercritical gas
• an adsorbant material which is made up from or includes the oxygen containing salts of. the basic metals such as the oxides, hydroxides, carbonates, sulphates, or the like
• the cholesterol or other sterols can be selectively removed from the adsorbant material by stripping the adsorbant material using the same, or another high pressure fluid, or by using organic solvents, such as propan-2-ol, and chloroform/methanol mixtures for example.
• organic solvents such as propan-2-ol, and chloroform/methanol mixtures for example.
• FIGURE 1 is a flow chart showing the extraction of fat and cholesterol from a cholesterol containing feed material such as meat, egg powder, or milk powder using a high pressure fluid and separating the cholesterol from the cholesterol/fat mixture by selective adsorption of the cholesterol on an adsorbant material.
• FIGURE 2 is a flow chart showing a similar process where the feed material is a fat or oil such as butter, plant oil, or fish oil, which is dissolved in the high pressure fluid, and the cholesterol is selectively removed therefrom by adsorption on an adsorbant material, and the substantially cholesterol free fat or oil is condensed from the high pressure fluid.
• a high pressure fluid is used either to dissolve the fat or oil, where the feed stock is butter, or an animal or plant oil; or where the feedstock is a matrix containing fats and cholesterol, e.g. meat, cheese, milk fats, egg powder, or the like, the fat and cholesterol can be extracted using the high pressure fluid.
• Suitable extraction fluids include :
• the high pressure fluid can be a liquid, or can be a sub or supercritical gas.
• pressure and temperature are the controlling parameters.
• a substance is in the supercritical state when it is above its critical temperature, Tc, and pressure, Pc. In this state, it can no longer be compressed into a liquid, for any pressure.
• a sub ⁇ rititcal fluid is a fluid with a pressure greater than Pc, but with a temperature less than Tc. Both sub and supercritical fluids can be used for extraction purposes.
• Suitable extraction Pressures 50 - 400 Bar (preferably 200-250 Bar) .
• Suitable extraction Temperatures 30 - 60°C (preferably 35°C) .
• the preferred extraction pressures are in the range 200-300 bar, and temperatures in the range 30-50°C, using C ⁇ 2 as the extracting agent. Temperatures above 60°C preferably should not be used where the cholesterol is extracted from a protein containing source so as to avoid protein denaturisation.
• CO2 was chosen as our preferred extractant because it is physiologically inert, it has bacteriost ic/bacteriocidal properties, has relatively low critical temperature and pressure requirements, is particularly suited to treating food products, and is compatible with our preferred adsorbant materials.
• the lipid mixture is extracted or dissolved into a high pressure (liquid or sub or supercritical) fluids.
• Separation of cholesterol or other sterols (as discussed below) from the dissolved lipid mixture is achieved by contacting the high pressure fluid mixture with an adsorbant which is made from or contains the oxygen containing salts of the basic metals such as the oxides, hydroxides, carbonates, sulphates, or the like.
• the oxygen containing salts may include (but are not limited to) : oxides, hydroxides, carbonates, sulphates, phosphates, acetates, or carboxylates.
• a wide range of basic metal oxides, hydroxides, carbonates, sulphates and other oxygen containing salts can be used and these include magnesium oxide, calcium oxide, strontium oxide, barium oxide, cadmium oxide, cobalt oxide, manganese oxide, nickel oxide, zinc oxide, and the hydroxides, carbonates, sulphates and other oxygen containing salts of these metals.
• Our preferred adsorbants preferentially adsorb cholesterol and other sterols, with minimal adsorption of the other lipids. Consequently a substantially cholesterol free lipid mixture can be obtained from the high pressure fluid as it leaves or is otherwise separated from the adsorbant.
• this will involve passing the high pressure fluid through a column or bed of the adsorbant material, although it is possible to add the adsorbant material in the form of a fine powder to the high pressure fluid, e.g. stirred into a tank and then separating the powder from the fluid by filtration, by a hydro-cyclone, a centrifuge, or other solid/fluid separation technique.
• the degree of separation will depend upon the quantity of high pressure fluid used. For example, where a bed or column of the adsorbant material is used, the bed or column of adsorbant can be regenerated by contacting it with a greater quantity of the same high pressure fluid. Alternatively a different fluid which strips off the cholesterol or other sterols more quickly may be used for regeneration.
• the final stage of the process involves the separation of the purified lipid mixture from the high pressure fluid. Options for achieving this include:
• Lipids are extracted from a feed material such as finely sliced and at least partly dried meat, by extracting the lipids with a high pressure fluid.
• the preferred fluid is sub or supercritical carbon dioxide in a preferred pressure range of 150 - 300 bar, maintained at a temperature within a preferred range of 30° - 60° C.
• the extracted lipids, mainly fat and cholesterol, dissolved in the high pressure fluid are then passed over a closely packed column of adsorbant material, which is preferably granulated or pelletized with a particle size chosen in order to provide a good flow path through the column, whilst at the same time maximising the surface area of the adsorbant material.
• adsorbant material which is preferably granulated or pelletized with a particle size chosen in order to provide a good flow path through the column, whilst at the same time maximising the surface area of the adsorbant material.
• the column has multiple entry and exit points so that different portions of the bed can be used at different times to adsorb the cholesterol. By suitably separating the different portions of the bed, it is possible to use one portion of the bed whilst another portion is being stripped of its cholesterol.
• the flow rate of the high pressure fluid, and the quantity of fat/cholesterol mixture dissolved in the fluid is preferably controlled so that substantially all of the cholesterol is selectively adsorbed on the bed (with minimal adsorption of the fat except where controlled separation of the triglycerides is required) so that the high pressure fluid leaving the bed in most cases consists of substantially all of the fat with complete or almost complete removal of the cholesterol present.
• the high pressure fluid leaving the bed is then processed to separate the fat from the high pressure fluid, and this can be achieved in a variety of ways, e.g. by a increase in temperature, or a decrease in pressure, or a combination of both.
• the preferred method involves stripping of the fat from the high pressure fluid by an increase in temperature to a level at which the solubility of the fat in the high pressure fluid is reduced, or becomes negligible. This ranges from 10-30°C greater than the extraction temperature for C0 2 - The fluid remains at high pressure, and is recycled.
• the fat can be stripped from the fluid by reducing its pressure. This can if desired be combined with a change in temperature.
• the pressure can be reduced to atmospheric, with no recycling of the fluid; or the high pressure fluid can have its pressure reduced to the range 50 - 100 bar and then recycled. In some instances a combination of both processes may be most economical.
• the resulting beef tallow can be added back to the meat, during reconstitution of the meat,product. Some or all of the fat can be added back in this way, depending upon the fat level required for the resulting meat product. For example, it may be desirable to produce a low fat (cholesterol free) meat product, in which case some of the beef tallow can be removed, and the rest of it redeposited on the meat product.
• a meat product e.g. beef
• This cholesterol free fat can be separated from the high pressure fluid, preferably by an increase in temperature as previously described, although it is equally possible to separate it by a decrease in pressure.
• the high pressure fluid is preferably recycled, and used to dissolve further butter fat, which then passes over the adsorbant material and the process continues as shown in the flow chart.
• the cholesterol is preferably stripped from the adsorbant material, as described above, to provide a substantially pure form of cholesterol.
• the adsorbant material is chosen in order to ensure that substantially all of the cholesterol is adsorbed on the bed and the resulting cholesterol free fat is suitable for use as a food product.
• the adsorbant material is physiologically acceptable, and is of relatively low cost, and does not preferentially bind the triacylglycerides, fatty acids, or other naturally occurring food sensitive products: e.g. flavourings, olfactory agents, colouring agents, or the like.
• the preferred material is calcium carbonate for use with high pressure carbon dioxide, as we have found that by using basic oxides or hydroxides with supercritical carbon dioxide they are converted in the adsorption column into the corresponding carbonate.
• calcium carbonate is an inert, low cost, naturally occurring mineral, it is the preferred material for use in this cholesterol/sterol adsorption process.
• Adsorbants Basic metal oxides, as well as their hydroxides, carbonates, sulphates, and other oxygen containing salts, are the preferred adsorbant materials.
• Calcium carbonate, calcium oxide, magnesium carbonate, magnesium oxide and magnesium hydroxide are the most preferred of the naturally occurring adsorbant materials, although other appropriate adsorbants include (but are not limited to) the oxides, hydroxides, carbonates, sulphates, and other oxygen containing salts of magnesium, calcium, strontium, barium, cadmium, cobalt, manganese, nickel, and zinc. They may be used alone or in mixtures, and preferably are used in their naturally occurring form.
• the properties of the adsorbant material depend on the crystalline structure (and thus the surface structure), and polar nature (acidic or basic) .
• the choice of adsorbant material will depend upon the design of the plant, the strength of adsorption of the material, and the particle size and strength of the material (in the case of a bed or column) is important to avoid channeling allowing the high pressure fluid to pass through the column without adsorption and it is also desirable to avoid the breakdown of the material into a fine powder which would have the opposite effect of clogging the column.
• the adsorbants could be provided in pelletized or granular form, or as naturally occurring minerals, or deposited onto suitable substrates such as glass beads or rings.
• the adsorbant material can be chosen in terms of its relative strength of adsorption. We have found that for a given anion the strongest adsorption of sterols by the oxygen containing salts of the basic metals is shown by magnesium and this decreases through nickel, cadmium, cobalt, zinc, calcium, strontium to barium which shows the least adsorption of this group.
• acidic oxides are not suitable for use with high pressure fluids, as they cause too strong an adsorption of all of the lipid material so that separation is difficult without overloading the adsorbant.
• acidic oxides include Silicic Acid, Florisil, and Alumina, and as such are to be excluded from the process of this invention.
• Any fluid which at high pressure (either as a liquid or as a sub or supercritical gas) exhibit solvent properties can be used with this invention.
• the following gases have critical properties in the correct range and are unobjectionable from the health point of view: Carbon dioxide, ethane, propane, ethylene, N0 2 , SF g , CF3CI, CF 2 C 2 , CH 2 C 2 , C 3 Fg, CHF3 and mixtures thereof, and other gases unobjectionable from a health point of view, and which will be sub or supercritical in temperature and pressure ranges suitable for the processing of foodstuffs.
• Entrainers Subcritical additives which have been shown to enhance the solubility of liquids or cholesterol, include: Propan-2-ol, ethanol, acetone, methanol, ether, ethylene dichloride and ethyl acetate, or other entrainers known in the art may be used to enhance the solubility of the lipids, and especially the solubility of cholesterol or other sterols in the high pressure fluid.
• Process conditions for the preferred solvent C0 2 and the preferred adsorbants MgC ⁇ , MgO, C C ⁇ 3, CaO: Pressure is in the range 100 - 400 bar can be used with a preferred range being 150 - 300 bar.
• Temperature is in the range 20° - 80°C can be used, with a preferred range being 30° - 60° C.
• Fat/Adsorbant Ratio 0.001g fat/g adsorbant to 0.11g fat/g adsorbant.
• Moisture Content of the Adsorbant material 0.2% w/w - 5.0% w/w, with the preferred moisture content being as low as possible. Similarly, the high pressure carbon dioxide is kept as dry as possible.
• Methods of contacting the fluid and the adsorbant Any suitable method of contacting the two phases can be used, and this is not necessarily limited to the passage of the high pressure fluid through a static column or bed of adsorbant material.
• the high pressure fluid can pass through a jet through which finely ground adsorbant also passes, or a finely powdered adsorbant material can be introduced into the high pressure fluid and stirred in a reaction vessel, or could be introduced into the high pressure fluid and pumped along with the fluid to be collected at the solvent/solute separation stage whereby the resulting "sludge" of adsorbant material on which the cholesterol is adsorbed can then be removed by appropriate physical processes such as filtration, by using a hydro-cyclone, or possibly by centrifuging. Nevertheless, it is preferred that a fixed bed of particulate or granular adsorbant material is used, in order to avoid abrasive reaction of fine particulate material passing through the plant with the high pressure carbon dioxide.
• Examples B and C show the separation of cholesterol from spiked lard samples, i.e. samples of lard in which the cholesterol level was artificially increased.
• Example D the separation of cholesterol from butter is combined with the partial fractionation of the triglycerides in order to show that is possible to use this invention to both remove the cholesterol from the butter fat and enhance the concentration of lower molecular weight triglycerides to provide* a more spreadable cholesterol free butter without changing any of its other food related characteristics.
• magnesium and calcium hydroxides were used as the adsorbant material whereas in example C, calcium carbonate was used.
• Example C X-ray analysis of the calcium hydroxide as used in example A at the end of a test run revealed that a significant proportion of the bed had been converted to calcite, and subsequent tests with calcium carbonate (Example C) showed that it is a suitable, and indeed, preferred, adsorbant material for use with carbon dioxide.
• Triglyceride Composition
• the recovered butter fat was considerably enhanced in concentration of lower molecular weight triglycerides, reduced in higher molecular weight triglycerides, and completely cholesterol free.
• the recovered butter oil also had a lower melting point, thus making it more spreadable at low storage temperatures.
• the butter fat obtained was yellow and the ratios of saturated to unsaturated fats was unchanged.

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• 1988
  • 1988-09-09 WO PCT/GB1988/000739 patent/WO1990002788A1/en not_active Application Discontinuation
  • 1988-09-09 KR KR1019900700966A patent/KR900701980A/ko not_active Application Discontinuation
  • 1988-09-09 BR BR888807920A patent/BR8807920A/pt not_active Application Discontinuation
  • 1988-09-09 JP JP63507368A patent/JPH05504975A/ja active Pending
  • 1988-09-09 EP EP88907756A patent/EP0434676A1/de not_active Withdrawn
• 1991
  • 1991-03-08 NO NO91910926A patent/NO910926L/no unknown
  • 1991-03-08 DK DK041891A patent/DK41891A/da not_active Application Discontinuation
  • 1991-03-08 FI FI911168A patent/FI911168A0/fi not_active Application Discontinuation

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