US3892789A - Process for the extraction of glyceride oils by selective solvents - Google Patents

Process for the extraction of glyceride oils by selective solvents Download PDF

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Publication number
US3892789A
US3892789A US406748A US40674873A US3892789A US 3892789 A US3892789 A US 3892789A US 406748 A US406748 A US 406748A US 40674873 A US40674873 A US 40674873A US 3892789 A US3892789 A US 3892789A
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oil
polar solvent
process according
solvent
linoleic acid
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US406748A
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Anthony Mesnard Parsons
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Lever Brothers Co
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Lever Brothers Co
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    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23D—EDIBLE OILS OR FATS, e.g. MARGARINES, SHORTENINGS OR COOKING OILS
    • A23D9/00—Other edible oils or fats, e.g. shortenings or cooking oils
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23D—EDIBLE OILS OR FATS, e.g. MARGARINES, SHORTENINGS OR COOKING OILS
    • A23D7/00—Edible oil or fat compositions containing an aqueous phase, e.g. margarines
    • A23D7/001—Spread compositions
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23D—EDIBLE OILS OR FATS, e.g. MARGARINES, SHORTENINGS OR COOKING OILS
    • A23D7/00—Edible oil or fat compositions containing an aqueous phase, e.g. margarines
    • A23D7/015—Reducing calorie content; Reducing fat content, e.g. "halvarines"
    • 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
    • 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
    • C11B7/0033—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 containing other heteroatoms in their molecule

Definitions

  • ABSTRACT Process for the recovery from edible oils containing at least 50% linoleic acid combined as glycerides, of a fraction enriched in combined linoleic acid, in which the oil is contacted with an organic polar solvent immiscible therewith, the liquid phases formed being separated and the enriched fraction recovered from the polar solvent.
  • Dialkyl lower amides are preferred polar solvents and sunflower, safflower and cottonseed oil are preferred oils.
  • lt' is widely accepted to be beneficial to include in the diet a fat intake containing a high proportion in its combined form of linoleic acid, a so-called essential fatty acid.
  • This contains two ethylenically unsaturated bonds, whereas linolenic acid contains three double bonds, and is less desirable nutritionally and more susceptible to deterioration in storage.
  • Sunflower oil often contains 60-70% linoleic acid, while safflower oil usually contains 7080%.
  • the remaining fatty acid content of these oils is shared principally between C and C saturated and monounsaturated fatty acids.
  • Such oils should be distinguished from drying oils which are characterized by even more unsaturation, with a high content of linolenic acid and other unsaturated fatty acids in combined form which contain three or more double bonds, which oils are often inedible.
  • the invention is based upon the observation that the glycerides of the highly unsaturated fatty acids commonly found in natural fats, i.e. linoleic and linolenic,
  • oils are more soluble in polar solvents than those of the principal saturated and mono-unsaturated acids commonly occurring with them, i.e. of 16 and 18 carbon atoms in chain length.
  • those oils are selected whose linolenic acid content is low, since this is a less desirable component, prone to atmospheric oxidation with the development of off-flavours and less desirable nutritionally.
  • sunflower and safflower oils maize and cottonseed oils are particularly preferred. soyabean oil less so but nevertheless within the scope of the invention.
  • the present invention proposes to increase the combined polyunsaturated fatty acid content of edible oils, particularly in glycerides of linoleic acid, of oils generally whose combined linoleic acid content is at least 50% by weight, by a process comprising contacting the oil with a suitable solvent system comprising an N- substituted amide solvent at a temperature at which two liquid phases are formed, one consisting of a fraction of the oil rich in combined linoleic acid which is dissolved in the polar solvent, and the other a lean fraction comprising the residual oil, separating the two fractions and removing the polar solvent from the rich fraction to recover an oil fraction rich in combined linoleic acid.
  • the invention is based upon the observation that the glycerides of the highly unsaturated fatty acids commonly found in natural fats, ie linoleic and linolenic, are more soluble in polar solvents than those of the principal saturated and mono-unsaturated acids commonly occurring with them, ie of 16 and 18 carbon atoms in chain length.
  • those oils are selected whose linolenic acid content is low, since this is a less desirable component, prone to atmospheric oxidation with the development of off-flavours and less desirable nutritionally.
  • sunflower and safflower oils maize and cottonseed oils are particularly preferred, soyabean oil less so but nevertheless within the scope of the invention.
  • a fat fraction may be obtained suitable for use in foods in which sunflower and safflower oils are conventionally used but which contains as much as 10 or 20% additional polyunsaturated fatty acid in combined form, or even more.
  • Suitable products include edible oils for salad frying oils, salad creams, margarine and low fat emulsion-type spreads and shortening.
  • Organic polar solvents suitable for use in the invention include amides containing two lower alkyl groups, preferably each containing up to 4 carbon atoms, attached to the nitrogen atom of the amide group, particularly N-lower alkyl pyrrolidones, particularly the methyl derivative and dimethyl formamide. It may be necessary with the former solvent to realise an adequate degree of immiscibility by the addition thereto of a minor amount of water or a lower alkylene diol having up to 4 carbon atoms, eg ethylene glycol, generally less than 15% of the latter and less than 2% water, according to the extraction temperature.
  • the oil is itself dissolved in a non-polar solvent with which the extracting solvent is immiscible, thereby increasing the density differences between the phases and thus facilitating their separation from one another and the selectivity extraction for polar relative to non-polar glycerides, ie for polyunsaturated to less highly unsaturated glycerides.
  • Suitable oil solvents include aliphatic hydrocarbons which can conveniently be handled in liquid form, ie saturated aliphatic hydrocarbons from 3 to carbon atoms in chain length, although the upper limit is not critical.
  • Suitable hydrocarbon solvents include propane, butane, hexane and other light fractions, particularly a heptane fraction with a boiling range (95%) 96-98C petroleum. These hydrocarbon solvents are essentially non-polar and are customarily adopted in the extraction of the oils with which the invention is concerned from their plant seeds following the conventional dressing operation, to increase the yield of oil.
  • the extraction using a polar solvent may be carried out continuously or batchwise.
  • a particularly effective method of carrying out continuous extraction is by the method of countercurrent liquid-liquid extraction.
  • the immiscible liquids flow in opposite directions through a column or columns fitted internally with means providing maximum contact between the two.
  • the columns may be packed with random packing, e.g. Raschig rings, or fitted with spaced plates in a manner well known in the art for the purpose of affording maximum liquid-liquid contact.
  • Alternative mixer/- settler apparatus may be used instead.
  • the polar and non-polar solvents or reflux oil if no non-polar solvent is used are fed into opposite ends of the column and the oil to be extracted from an intermediate position.
  • solvents are determined among other things by the requirement to provide substantial immiscibility and they should also be inert both towards the oil being extracted and to one another where two solvent systems are utilised. Their properties in this respect may be modified according to the temperature at which they are used.
  • Organic polar solvents selected for use in the invention must be substantially immiscible with the oil and/or its solution in a non-polar solvent.
  • the degree of immiscibility may however be materially affected by the temperature at which the extraction is carried out. Further, by appropriate choice of temperature the degree of selectivity exercised in the extraction process according to the invention, between unsaturated glycerides and others in the oil being extracted may be substantially modified by temperature change.
  • a non-polar solvent it should not be in excess of the amount of polar solvent used to extract the polyunsaturated fatty acid glycerides; for example, 4 to 40 parts of polar solvent per part of hydrocarbon, or other non-polar solvent, and in particular from 10 to 30 parts of polar solvent per part has been found satisfactory.
  • the relative amounts of the immiscible liquids should be selected bearing in mind the partition coefficients determining the distribution between the two solutes concerned, ie the glycerides of different degrees of unsaturation. In order to obtain the correct rates the degree of immiscibility should also be taken into account and preliminary experiments may be necessary to ascertain the best proportions to adopt.
  • a linoleate partition coefficient greater than 50 requires an excess of polar solvent so great as to be uneconomic and an upper limit of about is generally imposed.
  • the recovery of glycerides from the polar solvent used in the extraction is preferably effected by diluting with water and extracting with non-polar solvent followed if necessary by distillation to recover the solvents in a form suitable for recycling.
  • the extraction procedure is carried out at temperatures between 20 and +50C.
  • the lower temperatures may be necessary where a volatile hydrocarbon is used as a solvent, but in general preferably the extraction is carried out at moderately elevated temperatures within the above range.
  • the process may be carried out under atmospheric or superatmospheric pressures, the latter being necessary to avoid the use of excessively low temperatures where highly volatile solvents are used.
  • oils are preferably bleached and neutralised before treatment in the process of the invention.
  • the recovered enriched glycerides may be used for the manufacture of margarine and other edible emulsion spreads where a high content of polyunsaturated fatty acids in combined form is required.
  • a minor proportion of semi-solid or hard fat eg lauric fats and particularly coconut oil, palm oil or hardened fats, for example hardened soyabean oil and cottonseed oil or stearine fractions thereof, are preferably included in the fat composition for these purposes.
  • Apparatus suitable for carrying out a continuous extraction process for the separation of saturated and unsaturated fractions (these being used as comparative terms) of a glyceride oil in accordance with the invention comprises a pair of packed liquid-liquid extraction columns arranged in series and a fractionation column connected to the base of the second column for recovering the polar solvent, in a sufficiently purified form to be recycled to the top of the first column.
  • a recovery unit comprising for example a multiple effect evaporator, separator and distillation equipment is provided for each extraction column, to remove any hydrocarbon solvent from the separated oil fractions which are collected in the effluent from the tops of the extraction columns.
  • the oil for example sunflower oil
  • a non-polar solvent for example a light hydrocarbon solvent
  • this is admitted to the base of both columns countercurrent to the heavy polar solvent admitted to the top.
  • Each solvent may be previously saturated with the other.
  • a small proportion of water may be admitted with the base effluent passed from the first column to the top of the second column to facilitate extraction therein.
  • the saturated and unsaturated fractions of the sunflower oil are distributed between the hydrocarbon and polar solvents in the first column. Effluent from the tops of the columns are treated in the recovery units to remove any light solvent, consisting larely of the hydrocarbon, for example by evaporation. Polar solvent may be separated, for example by water washing, from the more saturated fraction of the oil.
  • an oil feed supply for example of sunflower oil, enters the system via line 11 and is introduced into extractive distillation column 10 between its ends, a polar solvent being introduced above and a non-polar solvent below the point of entry of the oil via lines 12 and 13, preferably at entry points adjacent the ends of the column, which may be packed randomly or otherwise furnished with plates, trays or the like to promote intimate contact in the column between the liquids.
  • a supply of non-polar solvent is also admitted via line 21, countercurrent to the stream of rich fraction, to strip this from the polar solvent.
  • this solvent is discharged from the lower extremity of column 22 via line 22, into a solvent recovery column 50 through a feed point between the ends thereof.
  • the column 50 isfitted with reflux condenser means 51, supply and return lines therefor 52 and 53 and discharge line 54 via which non-polar solvent is delivered to storage means 60.
  • Column heater 71 is similarly furnished with corresponding lines 72, 73, and 74, the latter supplying recovered polar solvent to storage means 70.
  • the evaporators 30 and 40 are correspondingly equipped with heating means 31 and 41, delivery and return lines therefor 32, 33 and 42, 43 and discharge lines 34, 44 from which the separated lean and rich oil fractions are collected.
  • the volatile products of the evaporators 30 and 40 consisting largely of solvent, are delivered via lines 34, 44 and condensers 80, 90 to separators 81, 91, from which separated non-polar solvent is discharged to storage 60 via lines 82, 92 and polar solvent via lines 83, 93 to storage 70.
  • Example 2 In this Example a series of tests on the solvents used in Example 1 in accordance with the invention was carried out as described in that Example, using however heptane as a non-polar solvent to raise the density difference between the phases and improve selectivity.
  • the non-polar phase was weighed and washed with water as before.
  • the washed residue (epiphase) was weighed in order to determine the miscibility, the second solvent was removed by evaporation in order to determine the quantity of oil remaining in the epiphase and to provide a sample for fatty acid analysis.
  • a partition coefficient calculated on the basis of the distribution of combined fatty acids themselves, was then determined, representing the concentration of linoleic acid as triglycerides in the epiphase divided by that in the hypophase.
  • the factor B in Table 2 is the ratio of partition coefficients for linoleic acid and the remaining acids and therefore indicates the degree of enrichment, relative to polyunsaturated fatty acid content, effected by the extraction.
  • a minimum [3 value of 1.4 was regarded as providing effective separation.
  • EXAMPLE 3 A continuous liquid-liquid extraction of sunflower oil using dimethylformamide and heptane was carried out on sunflowerseed oil at 20C in a 10-stage mixer settler of the Wall type (AERE/CElR 1730, Harwell 1955), in the modified form described by Ellis and Gibbon (Proceedings, Symposium Institute Chem. Eng. 24-26 April 1963).
  • the oil, containing 65.4 wt linoleic acid was fed at a rate of 3 g/hr. to the epiphase leaving stage 5, while dimethylformamide and heptane, each previously saturated with the other, were fed to stage 10 and stage 1 at rates of 225 and 8.7 g/hr.
  • the heavy solvent effluent Upon raising the oil flow rate to 5.3 g/hr. the heavy solvent effluent was found to contain 28.5% of the oil, with a linoleic acid content of 81.9%, the remainder of the oil in the light solvent containing 56.8% linoleic acid.
  • EXAMPLE 4 A continuous liquid-liquid extraction of sunflowerseed oil using N-methyl pyrrolidone and ethyl glycol in a 9:1 w/w mixture was carried out at 35C in a mixer settler apparatus with 12 stages.
  • Process for increasing the combined polyunsaturated fatty acid content of edible oils having a combined linoleic acid content of at least 50% by weight comprising contacting the oil with a suitable solvent system comprising an N-substituted amide solvent selected from the group consisting of dimethyl formamide, N-lower alkyl pyrrolidone, and 1,6- bispyrrolidon-2-yl-,-hexane at a temperature at which two liquid phases are formed, one consisting of a fraction of the oil rich in combined linoleic acid which is dissolved in the polar solvent, and the other a lean fraction comprising the residual oil, separating the two fractions and removing the polar solvent from the rich fraction to recover an oil fraction rich in combined linoleic acid.
  • a suitable solvent system comprising an N-substituted amide solvent selected from the group consisting of dimethyl formamide, N-lower alkyl pyrrolidone, and 1,6- bispyrrolidon-2-yl
  • the polar solvent includes either a minor amount of water or a lower alkylene glycol containing up to 4 carbon atoms in an amount sufficient to render said polar solvent immiscible with said oil.
  • nonpolar solvent comprises a paraffin with from 3 to 10 carbon atoms.
  • nonpolar solvent comprises a light petroleum with a boiling range from 96 to 98C.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Analytical Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Fats And Perfumes (AREA)
  • Edible Oils And Fats (AREA)
US406748A 1972-10-18 1973-10-15 Process for the extraction of glyceride oils by selective solvents Expired - Lifetime US3892789A (en)

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GB4803972A GB1444551A (en) 1972-10-18 1972-10-18 Solvent extraction of glyceride oils

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JP (1) JPS4974206A (en)van)
AU (1) AU471905B2 (en)van)
BE (1) BE806254A (en)van)
BR (1) BR7308116D0 (en)van)
CA (1) CA1022185A (en)van)
DE (1) DE2352346A1 (en)van)
ES (1) ES419773A1 (en)van)
FR (1) FR2203593B1 (en)van)
GB (1) GB1444551A (en)van)
IE (1) IE38372B1 (en)van)
IT (1) IT1020517B (en)van)
LU (1) LU68642A1 (en)van)
NL (1) NL7314265A (en)van)
SU (1) SU606552A3 (en)van)
ZA (1) ZA737991B (en)van)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5405633A (en) * 1992-10-08 1995-04-11 Skw Trostberg Aktiengesellschaft Process for the extraction of fats and oils
ES2080685A1 (es) * 1994-02-11 1996-02-01 Consejo Superior Investigacion Procedimiento para la separacion no destructiva de los pigmentos cloroplasticos y la fraccion glicerica en aceites y oleorresinas vegetales.
RU2124045C1 (ru) * 1992-06-16 1998-12-27 Скотиа Холдингс ПЛС Способ разделения соединений, содержащих две, три или более этилен-ненасыщенных связей, экстрагирующее средство
US5928478A (en) * 1998-09-14 1999-07-27 Berg; Lloyd Separation of linoleic acid from linolenic acid by azeotropic distillation

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200391A (en) * 1939-01-17 1940-05-14 Pittsburgh Plate Glass Co Solvent extraction of glyceride oils
US2573900A (en) * 1948-11-26 1951-11-06 Pittsburgh Plate Glass Co Treatment of glyceride oils
US3376326A (en) * 1964-12-31 1968-04-02 Procter & Gamble Interesterification of glycerides

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200391A (en) * 1939-01-17 1940-05-14 Pittsburgh Plate Glass Co Solvent extraction of glyceride oils
US2573900A (en) * 1948-11-26 1951-11-06 Pittsburgh Plate Glass Co Treatment of glyceride oils
US3376326A (en) * 1964-12-31 1968-04-02 Procter & Gamble Interesterification of glycerides

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2124045C1 (ru) * 1992-06-16 1998-12-27 Скотиа Холдингс ПЛС Способ разделения соединений, содержащих две, три или более этилен-ненасыщенных связей, экстрагирующее средство
US5405633A (en) * 1992-10-08 1995-04-11 Skw Trostberg Aktiengesellschaft Process for the extraction of fats and oils
ES2080685A1 (es) * 1994-02-11 1996-02-01 Consejo Superior Investigacion Procedimiento para la separacion no destructiva de los pigmentos cloroplasticos y la fraccion glicerica en aceites y oleorresinas vegetales.
US5928478A (en) * 1998-09-14 1999-07-27 Berg; Lloyd Separation of linoleic acid from linolenic acid by azeotropic distillation

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ES419773A1 (es) 1976-03-01
BE806254A (fr) 1974-04-18
GB1444551A (en) 1976-08-04
AU471905B2 (en) 1976-05-06
FR2203593B1 (en)van) 1978-02-17
NL7314265A (en)van) 1974-04-22
BR7308116D0 (pt) 1974-06-27
DE2352346A1 (de) 1974-05-02
IE38372B1 (en) 1978-03-01
CA1022185A (en) 1977-12-06
FR2203593A1 (en)van) 1974-05-17
JPS4974206A (en)van) 1974-07-17
LU68642A1 (en)van) 1974-05-09
SU606552A3 (ru) 1978-05-05
IT1020517B (it) 1977-12-30
AU6137273A (en) 1975-04-17
ZA737991B (en) 1975-05-28
IE38372L (en) 1974-04-18

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