CA1157883A - Chemical degumming of crude vegetable oils - Google Patents
Chemical degumming of crude vegetable oilsInfo
- Publication number
- CA1157883A CA1157883A CA000369279A CA369279A CA1157883A CA 1157883 A CA1157883 A CA 1157883A CA 000369279 A CA000369279 A CA 000369279A CA 369279 A CA369279 A CA 369279A CA 1157883 A CA1157883 A CA 1157883A
- Authority
- CA
- Canada
- Prior art keywords
- oil
- degummed
- acid
- crude
- rapeseed oil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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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
- C11B3/02—Refining fats or fatty oils by chemical reaction
- C11B3/04—Refining fats or fatty oils by chemical reaction with acids
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/74—Recovery of fats, fatty oils, fatty acids or other fatty substances, e.g. lanolin or waxes
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Microbiology (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Fats And Perfumes (AREA)
Abstract
ABSTRACT
A process for degumming a crude vegetable oil, especi-ally rapeseed oil, containing gums in the form of hydratable and non-hydratable phospholipids to provide degummed oil hav-ing a low residual phosphorus content by maintaining the crude oil at a temperature of about 40°C. or above 40°C., preferably within the range of from about 40° to about 75°C., and then adding an organic acid, such as citric acid, follow-ed by water, under effective mixing conditions to achieve hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, to centrifugation to separate aqueous sludge therefrom and provide the desired degummed vegetable oil which is suitable for further refin-ing.
A process for degumming a crude vegetable oil, especi-ally rapeseed oil, containing gums in the form of hydratable and non-hydratable phospholipids to provide degummed oil hav-ing a low residual phosphorus content by maintaining the crude oil at a temperature of about 40°C. or above 40°C., preferably within the range of from about 40° to about 75°C., and then adding an organic acid, such as citric acid, follow-ed by water, under effective mixing conditions to achieve hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, to centrifugation to separate aqueous sludge therefrom and provide the desired degummed vegetable oil which is suitable for further refin-ing.
Description
CHE:MICAL DEGUMMING O~l CRUDE VEGET~LE OII,S
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Crude, vegetable oils yenerally contain grea-ter than 95~ of -triylyceride compounds derived from long chain ~at-ty aclds. In -the commercial process of crushing or extractiny oilseeds to produce crude vege-table oils, several minor im-puri-ties such as free fa-tty acids, phospholipids, waxes, sugars, carotenoids, chlorophylls ancl various metals, may be present in the crude oils.
Three types of processes are commonly used -to extract vegetable oils from oil bearing seeds and fruits, such as rapeseed (Brassica campestris and Brassica napus), namely, mechanical expelliny, direct solvent e~traction or a combi-nation process of prepressing and solvent extraction. In all three processes, the native seed is subjected to vary-ing parameters of flaking or rolling, heating, moisture addition or drying, for varying periods of time, in order to condition the oil bearing seed material for oil e~traction.
The quality of oils ob-tained from the three processes may differ with respect to -the impurities present due to dif-ferences in seed preparation prior to oil extraction. Fur-thermore, in processes employing a solvent, such as hexane,greater quan-tities of impurities may be co-extracted with the oil.
To produce vegetable oils with acceptable flavour, functionality and shelf life, crude oils must be refined to remove substan-tially all of the contaminating impurities.
Due to the diverse chemical nature of the impurities in crude oils, commercial refining of vegetable oils involves several successive stages of purification processes. Tra-ditionally, rapeseed oil has generally been refined using the sequence of degumming, alkali refining, bleaching, and deodourization. Phospholipids present in a crude vegetable oil, such as rapesee~ oil, are removed mainly in degumming and alkali refining. Refined oils also have had free fa-tty acids removed, and me-ta].s and several coloured impurities substan-tially recluced, in these processes~
The process of chemical degumming, which is the pro-cess of the present invention, accomplishes the removal of substantially all of the phosphorus, presumably present in the form of hydratable and non-hydratable phospholipids, from crude oils by means of a sinyle stage of chemical de-gumming. r~'he produc-t degummed oil thus obtained from this chemical degumminy process has had little or none of the free fatty acid removed therefrom.
Phospholipids present in crude oils are a complex mixture of triglyceride - like compounds in which, however, one fatty acid radical has been replaced by a phosphorylated radical. Phospholipids can be generally classified into two types, namely, the hydratable phospholipids which when created with water become oil-insoluble and the non-hydra-table phospholipids, which are mainly calcium and magnesiumsalts of phosphatidic acid. Water/steam degumming is a pro-cess whereby phospholipids having an affinity for water are hydrated, rendered insoluble in the oil and are then sepa-rated from the crude oil, generally by centrifugation. The degree of removal of the total phospholipids depends to a great extent on the quality of the crude oil produced in the primary extraction process. In practice, degummed rapeseed oil, produced by the usual water/steam degumming process, generally contains higher quantities of residual phosphorus than other common degummed vegetable oils, such as degummed ~ soybean oil or degummed sunflower oil.
In the whole seed, phospholipids are present substan-tially in an hyd:ra-table form. ~iowever, during the process of crude oil extraction, and also in damaged seeds, hydra-table phospholipicls can be converted by various enzymes to non-hydra-table phospholipids. Crude oils may contain, therefore, varying proportions of hydratable and non-hydra-table phospholipids.
In rapeseed crushing, using the common prepress-sol-vent extraction process, expelled oils are found to contain about 0.3-1.0% phospholipids while solven-t extracted oils contain about 2.0-3.5% phospholipids. The typical crude rapeseed oi.l known to -the ar-t, obtained when blended in the usual proportion of 2 parts of expelled rapeseecl oil with 1 part of solvent e~tracted rapeseed oil, contains about 0.9-1.6% phospholipids.
I'he common industrial practice of degumming vegetable oils consists of treating crude or extracted oils with water or steam in order to hydrate the phospholipids, thereby rendering them insolube in the oils, in the form of an aqueous sludge phase. The latter, which is usually sepa-rated from the degummed oil by centrifugation, may be iso-lated and vacuum dried to yield a lecithin by-product.
Alternatively, the sludge may be incorporated into the ex-tracted meal, thereby increasiny the nutrient and energy value of the meal by-product. Frequently, only solvent ex-tracted oils are degummed prior to blending with expelledoil to produce a degummed oil. This practice evolved as it was found that phospholipids in solvent extracted oil are predominately of the hydratable type whereas phospho-lipids in expelled oil are predominately of the non-hydra-table type. However, the proportion of hydratable to non-hydratable phospholipids in either expelled oil or solvent ~a..~ 3 extracted oil is su~ect to considerable varia-tion depending on the quality of the processed seed and of processlny para-MeterS.
The non-hydratable phospholipids remaininy in degumm-ed oil are present mainly in the form of calcium and magne-sium salts of phosphatidic acid. Pr:ior to alkali refining, an acid is used to acldula-te these calcium and maynesium phosphatidates into hydratable phosphatidic acid which may -then be removed in the alkali reining stage.
According to the known ar-t, inorganic acids, such as phosphoric, hydrochloric, nitric, sulfuric and boric acid, have been examined as chemical degumming agents, as have organic acids, such as ace-tic, citric and oxalic acid.
Additionally, the use of mono-, di- and tri-chloroacetic acid and ace-tic anhydride have been examined.
In practice, phosphoric acid is most commonly used in the acid pre-treatment of degummed oils prior -to alkali refining. Following the acid pre-treatment, sodium hydr-oxide is mixed with the oil in a slight excess of -the stoichiometric requirement to neutralize -the added acid as well as the phosphatidic acids and free fatty acids pre-sent in the oil. The soapstock containing the sodium salts of these acids, as well as some entrained oil, is separated from the neutralized refined oil, usually by centrifugation.
It is customary for the soapstock to be acidulated to pro duce acidulated fatty acids, which are valued as an animal feedstuff, or for the soapstocks to be fully saponified, then acidulated, in order to recover fatty acid oils and glycerine.
The common practice of water degumming followed by acid pre-treatment and alkali refining of the degummed oil 1 1S78g~
has several dlsadvantacJes. Firs-tly, significant quan-tities of neutral oil are lost in each stage of the sequence of deyu~ming and refinincJ. In particular, the presence of phospholipids at -the reEining stage can result in an incre~
ased amount of an emulsion layer which may he difficult to separate and entrains neutral oil. In general, degummed oil containlng increased quantities of phospholipids requires higher proportions of phosphoric aci.d as a pre-treatment agent and, in turn, hi~her levels of sodium hydroxide in the alkali refining process and sulfuric acid in -the soap-spli-t-ting process. As a result, aqueous wastes from alkali refin-ing are increasingly con-taminated by organic and inoryanic waste materials. These materials can be significant envir-onmental pollutants and must frequently be removed from waste water prior to dischaxge.
As mentioned previously, the known art indicates that several alternative reagents have been examined for removing phospholipids from crude vegetable oils. Organic acids, in--cluding citric acid, have long been known to assist in the hydration of phospholipids including the non-hydratable types.
Acids, such as oxalic, acetic and citric acid, have been ex-amined as chemical degumming agents in order to reduce the environmental discharge of phosphates in waste waters.
Recently, a degumming process employing citric acid has been described in Canadian patent No. 1,060,0~1. This process involves the sequential addition of concentrated citric acid and wa-ter following a carefully controlled series of temperature adjustments. For example, it is pre~erred that citric acid be added to the oil at a temperature of at least 60C and more particularly within the range of 65 to 90C. Fur-thermore, it is also preferred that water be added ~ J'~o3 to the aci~-concli-tione~ oiI at a temperature below ~0C'., ~re-ferably at 2~ -to 35C. It is an essential requirement o~ the process that -the mixture o~ o.il, acid and water be maintained at a temperature below ~0C or at least 5 minutes before separating the aqueous sludge. Indeed, it is indicated that a temperature of 20 to 35C. for a period of at leas-t 30 min-utes is desirable before separatiny t:he aqueous sludge.
We have now :Eouncl, and herein lies our invention, -that a novel improved process which embodies a sirnplistic approach to temperature con-trol in a chemical degumminy process of crude vegetable oils can provide a degummed vegetable oil of a quality which has not hi-ther-to been readily obtainable.
We have now found that a crude veyetable oil, for ex-ample crude rapeseed oil, can be efficiently and economicall~
degummed to provide a degurnmed oil having a lower residual phosphorus content than that normally obtainable by water/
steam degumming and, moreover, with a residual phosphorus content generally less than about 50 parts per million (ppm) and frequently less than about 30 ppm by using an organic acid, such as citric acid, and water as the chemical degumm~
ing reagents provided that the process is maintained at a constant temperature of about 40C or higher and preferably within the range ol about 40 to about 75C.
Our invention as claimed herein is a novel improved process for degumming a crude vegetable oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed vege-table oil having a low residual phosphorus content which comprises maintaining the crude vegetable oil at a temperature of or above about 40C., adding an organic acid thereto under effective mixing con-ditions to substantially compl.ete reaction between the acid ~ ~57883 and -the phospholipic:~s, thereafter adding sufficient water under the effective mixing conditions to achieve subsequent hydration of -the acid-conditioned phospholipids and finally subjec-ting -the oil/acid/wa-ter mix-ture, at the s-tated temper-ature, to a separa-tion procedure to separate aqueous sludye therefrom and thereby provide the degunlmed vegetable oil having low residual phosphorus conterlt.
By operat.ion of this inventive process, it is possible to obtaln a degummed vegetable oil, and especially degummed rapeseed oil, having a residual phosphorus content of less than about 50 ppm and, often, to obtain such an oil having a ~ar-ticularly low residual phosphorus content of less than about 30 ppm.
The temperature to be maintained throughout the oper-ation of the process is preferably within the range of from about 40 to about 75C., more particularly from about 40 to about 65C and especially from about ~0 to about 55C.
A most effective temperature for operation of thc degumming process i5 within the range of from about 45 to about 55C.
The crude vegetable oil used as starting material may be any one of the oils commonly used as vegetable oils and may be, for example, rapeseed oil, soybean oil, rice bran oil, sunflower seed oil, safflower seed oil, sesame seed oil, flax(linseed) oil, grapeseed oil, groundnut oil, coconut oil, palm oil, cottonseed oil, maize(corn~ oil or palm kernel oil.
Ihe general applicability of our novel improved pro-cess for degumming a vegetable oil, in comparison with water degumming, is illustrated in Table I for a selection of crude vegetable oils including rapeseed oil, soybean oil, sunflower oil, safflower oil and linseed oil. Of these, rapeseed oil is an important vegetable oil which can now be produced in B~3;3 I ~ _ .
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_ .. _ ., . . _ , a declllmmed forrn ancl in a h:icJh qual:Lty which has not hither-to been readily ob-tainable.
The organic acid -to be usecl in the degumminy process is pre~erably ci-tric acid. It is generally added to -the crude oil, maintained within -the stat:ed temperature range, in the form of a coneentrated aqueous solution. A 50% con-centra-ted aqueous solution of citric acid has been found -to be advantageous. rrhe amoun-t of acid used in the process will generally be dependent upon the quality of the erude oil used as starting material, the me-thod by which sueh oil has been obtained from the original oil-bearing material and the number and amount of various undesirable impurities present in -the oil. We have found that ci-tric acid used in an amount of from about 0.05% to about 0.5% by weight based upon the weight of erude oil is usually adequate provided that there is thorough and effeetive mixing between the erude oil and -the eitrie acid in order to substanti.ally eom plete reaetion between the eitrie aeid and the phospholipids present in the erude oil. A preferred amount of eitric aeid is from about 0.1% to about 0.25% w/w based on erude oil and we have found that about 0.15% w/w of eitrie aeid is a par-tieularly efficient eoneentra-tion to be used.
After the crude oil has been treated with the organie aeid, sueh as eitrie aeid, and the phospholipids in the oil have thus beeome acid-conditioned, the proeess is eompleted by adding water to the oil/aeid mixture to aehieve hydration of the aeid-eonditioned phospholipids. A suitable amount of water to be added is within the range of from about 0.5%
to about 5% by weight based upon the weight of erude oil.
A preferred amount of water is within the range of from about 1% to about 3% by weight based upon the weignt of erude g ~ ~'3'o'~
oil and a most effec-tive amount of wa-ter is about 2~ w/w oE
crude oil.
The hydrated acid-conditioned phospholipids are not soluble in the thus treated oil and are therefore precipita-ted therefrom in the form of an aqueous sludge which can -then be separated from the residual deyummed oil. This separation may generally be carried out most efficiently and con~enient-ly by means o-f a centrifuye. The mix-ture of degummed oil and aqueous sludge is subjected to centrifuyation wi-th the result that the a~ueous sludge is separated from the oil and the oil thus obtained is a deyummecl vege-table oil having a low residual phosphorus content. In practice, it is often found that the degummed vegetable oil, and particularly de-gummed rapeseed oil, has a residual phosphorus content of less than about 50 ppm and frequently less than abou-t 30 ppm.
The inventive process as claimed herein also includes a novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil having a low residual phosphorus content which comprises maintaining the crude rapeseed oil at a temperature of or above 40C., adding a concentrated aqueous solution of citric acid there-to under effective mi~ing conditions to substantially com-plete reaction between the acid and the phospholipids, thereafter adding sufficient water under the effective mix-ing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/
acid/water mixture~ at the stated temperature, to a separa-tion procedure to separate aqueous sludge therefrom and provide the degummed rapeseed oil having low residual phos-phorus content. The degummed rapeseed oil thus obtained may have a resiclual phosp:horus content of less -than about 50 ppM
and even :Less -than abou-t 30 ppm.
In the drawing, which shows a flow shee-t ~iayram of a preferred embodiment for carrying out the process of the in-5 vention, crude vegetable oil is recei.ved from a crude oiltank 1 at a rneasured flow rate and is passed into a heat ex-changer 2 where it is either heated or cooled, as necessary, to the required temperature of about 40C or above 40C, preferably in the range of about 45 to about 55C. The oil, at the appropriate temperature, is then passed to the acid mix tank 3 and ci-tric acid is added to the oil in tank 3 at a controlled rate of 0.15% by weight based upon the weight of the oil, in -the form of a 50% concentrated aqueous solu-tion. The latter is stored in a citric acid holding tank 6.
The acid mix tank 3 is of a shape and size such that thor-ouyh and effective mixing conditions are available to en-sure substantially complete reaction between the citric acid and the phospholipids present in the crude oil. In practice, we have found that reaction times of about. 10 minutes or greater have been necessary for such complete reaction. The oil containing the acid-conditioned phospholipids is then passed into a water mix tank 4 and water is added to the oil at a rate of abou-t 1% to 3% by weight, preferably 2% by weight, based upon the weight of the crude oil. This water mix tank 4 is of a shape and size such that thorough and effective mixing takes place and an adequate reaction time allows complete hydration of the acid-conditioned phospho~
lipids to take place. It has been found, in practice, tha-t reaction times of about 20 minutes or greater have been necessary in order to effect complete hydration in the water mix tank 4. The mixture of hydrated phospholipids ~ 3 and deg-lmmed oil thus obtained i9 separa-ted by means of a centrifuge 5 which thereb~ provides an aqueous sludge and a degummed oil having a low residual phosphorus conten-t.
This phosphorus conte~t may be as low as 50 ppm or less and, frequen-tly, it may be as low as 30 ppm or less. Experience has shown that -the aqueous sludge so procluced is consider-ably more viscous than an aqueous sludge normally produced in a water or steam degumming process. As a result, the downstream physical handllng system for the aqueous slu~lge produced by the improved chemical degumminy according to the present inventive process must be designed in a manner to accommodate the physical nature of the aqueous sludge. In addition, it may be required to operate certain centrifuges at lower capacities than is customary in traditional water degumming processes.
The feasibility of the described process has been confirmed on an industrial scale at capacities of 4000 to 5000 kg of crude rapeseed oil per hour. Three examples of chemical degumming of crude rapeseed oils using the pro-cess of this invention (Experiments 14 to 16) are comparedin Table II with an example of water degumming wherein no citric acid is present (Experiment 13).
It is clear from these comparative experiments in Table II that more than 95% of the phosphorus in a crude rapeseed oil containing significant quantities of hydra-table and non-hydratable phospholipids can be removed by chemical degumming compared with only 78~ of the phosphorus in a similar crude rapeseed oil treated by a water degumm-ing process. In fact, it can be seen that crude rapeseed oils were chemically degummed by using citric acid and water to provide degummed rapeseed oils having a residual c~3 _ O ~ .
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The chemical degumming of prepress rapeseed oils con-taining mainly non-hydratable phospholipids (Experiments 17 ancl 18 in Table II) was somewhat less efficient in reducing phosphorus content than was chemical degumming of crude rapeseed oils consistiny of mixtures of prepxess oil and solvent oil, or of solvent oil alone, under similar degumm-ing condi-tions. These examples o:E chemical deyumming of sample prepress oils do not limit the technical nor prac-tical application of the inventive process to chemicallydegum prepress oils or similar such oils to a lower resid-ual phosphorus con-tent than would normally be achievable by water or steam degumming. Furthermore, these examples also do not ~egate the feasibility of chemically degumming a crude prepress oil or similar such oils to provide de-gummed oils containing a low resldual phosphorus content, for example less than about 50 ppm of phosphorus, according to the described inventive process provided such oils con-tain significant quantities of hydratable phospholipids.
To test the effect of citric acid rate on the chemi-cal degumming of crude rapeseed oils as produced in a pre-press/solvent extraction process, several additional chem-ical degumming experiments were conducted, the results of which are compared in Table III.
Comparing the results obtained from experiments l9 to 29 as shown in Table III, it can clearly be seen that several crude rapeseed oils containing phosphorus levels of the order of from 380 to 540 ppm have been chemically degummed in a satisfactory manner, over the temperature range of 45 to 75C., using citric acid addition rates ~I h-- o (~1 ~D o a~ o~ o o ~ ~I r`
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X ~ . . . . _ ~ v __ J~3 over the range of from 0.L~ to O . 25~ by welght bas~d upon the weigh-t of crude oil. The degur~led rapeseed oils thus obtained had a residual phosphorus con-ten-t of less -than 50 ppm and, lndeed, it is par-ticularly notable that -the deyummed rapeseed oils ob-~ained in Experiments 21, 22, 2~, 27 and 28 had resldual phosphorus con-tents within the extremely low range of from 6 to 14 ppm.
These results demonstrate that an excess of citric acid does not detract from -the prac-t:ical operation of our inventive process. However, it would be obvious to one skilled in the art that a minimum concentration of citric acid is required for the inventive process, the minimum being dependent to some extent on the composition of the phospholipids present in the crude oil used as s-tarting material.
It will be appreciated by one skilled in the art of refining crude vegetable oils ~hat, although our inventive process has been illustrated and exempliied in detail by reference to rapeseed oil, which is an important commercial product, it is also possible to apply our inventive process to other crude vegetable oils. Some comparative examples of such alternative vegetable oils are mentioned in the foregoing description and in Table I. Operation of our process produces corresponding degummed vegetable oils hav-ing low residual phosphorus contents. The degummed vege-table oils frequently have a residual phosphorus content of less than about 50 ppm and, in some instances, they have a residual phosphorus content of less than about 30 ppm.
Such residual phosphorus con-tents are substantially lower than those obtainable by water degumming of the identical crude oils.
~ ~ a ~ 3 ~ part from the use of an organic acid, such as citric acid, in the range of Erom about 0.05% to 0.5~ w/w of crude oil, preferably 0.1~ to 0.25% w/w of crude oil, and ~ater, in the range of 0.5~O -to 5O w/w of crude oil, preferably 1%
to 3~O w/w of crude oil, to achieve acid-conditioning and hy-dra-tion of the phospholipids in the crude oils, -the funda-mental and essen-tial feature of our :inventive process is the use of a constant -tempera-ture within a specifi.ed range throu-ghout the operation of the process. This collstan-t temperature may be as low as abou-t 40C. but it :Ls desirably within the range of from abou-t 40 to about 75C. and preferably within the range of from about 45 to about 55C.
We have found tha-t operation of this inventive process using crude rapeseed oil as starting material at a tempera-ture of about 45 -to about 55C. provides degummed rapeseed oil having a residual phosphorus content of less than about 50 ppm and, more desirably, less than 30 ppm.
Thus, the process as claimed herein, is furthermore a process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 50 ppm of residual phosphorus which comprises main-taining said crude rapeseed oil at a temperature of about ~5 to 55C., adding citric acid in the form of a 50% w/w aqueous concen-trated solution -thereto at a rate of about 0.15% citric acid by weight of the oil under effective mix-ing conditions to substantially complete reaction between said acid and said phospholipids, thereafter adding suffi-cient water at a rate of about 2% by weight of the oil under said effective mixing conditions to achieve subsequent hydr-ation of the acid-conditioned phospholipids and finally sub-~ 157883 jecting the oil/acid/water mixture, within -the sta-ted tempera-ture range, to a separation procedure by centrifugation to separa-te aqueous sludge -therefrom and provide -the degummed rapeseed oil havincJ a residual phosphorus con-tent of less than about 50 ppm.
Upon experimentation, we have found -that degummed rape-seed oil having a residual phosphorus con-tent of less than 30 ppm has the potential to ~e~steam refined in a process similar to tha-t commonly used for palm oil, thereby producing a finished rapeseed oil similar in quali.ty -to a refined, bleached and deodourized rapeseed oil produced in a tradi-tional alkali refining process.
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Crude, vegetable oils yenerally contain grea-ter than 95~ of -triylyceride compounds derived from long chain ~at-ty aclds. In -the commercial process of crushing or extractiny oilseeds to produce crude vege-table oils, several minor im-puri-ties such as free fa-tty acids, phospholipids, waxes, sugars, carotenoids, chlorophylls ancl various metals, may be present in the crude oils.
Three types of processes are commonly used -to extract vegetable oils from oil bearing seeds and fruits, such as rapeseed (Brassica campestris and Brassica napus), namely, mechanical expelliny, direct solvent e~traction or a combi-nation process of prepressing and solvent extraction. In all three processes, the native seed is subjected to vary-ing parameters of flaking or rolling, heating, moisture addition or drying, for varying periods of time, in order to condition the oil bearing seed material for oil e~traction.
The quality of oils ob-tained from the three processes may differ with respect to -the impurities present due to dif-ferences in seed preparation prior to oil extraction. Fur-thermore, in processes employing a solvent, such as hexane,greater quan-tities of impurities may be co-extracted with the oil.
To produce vegetable oils with acceptable flavour, functionality and shelf life, crude oils must be refined to remove substan-tially all of the contaminating impurities.
Due to the diverse chemical nature of the impurities in crude oils, commercial refining of vegetable oils involves several successive stages of purification processes. Tra-ditionally, rapeseed oil has generally been refined using the sequence of degumming, alkali refining, bleaching, and deodourization. Phospholipids present in a crude vegetable oil, such as rapesee~ oil, are removed mainly in degumming and alkali refining. Refined oils also have had free fa-tty acids removed, and me-ta].s and several coloured impurities substan-tially recluced, in these processes~
The process of chemical degumming, which is the pro-cess of the present invention, accomplishes the removal of substantially all of the phosphorus, presumably present in the form of hydratable and non-hydratable phospholipids, from crude oils by means of a sinyle stage of chemical de-gumming. r~'he produc-t degummed oil thus obtained from this chemical degumminy process has had little or none of the free fatty acid removed therefrom.
Phospholipids present in crude oils are a complex mixture of triglyceride - like compounds in which, however, one fatty acid radical has been replaced by a phosphorylated radical. Phospholipids can be generally classified into two types, namely, the hydratable phospholipids which when created with water become oil-insoluble and the non-hydra-table phospholipids, which are mainly calcium and magnesiumsalts of phosphatidic acid. Water/steam degumming is a pro-cess whereby phospholipids having an affinity for water are hydrated, rendered insoluble in the oil and are then sepa-rated from the crude oil, generally by centrifugation. The degree of removal of the total phospholipids depends to a great extent on the quality of the crude oil produced in the primary extraction process. In practice, degummed rapeseed oil, produced by the usual water/steam degumming process, generally contains higher quantities of residual phosphorus than other common degummed vegetable oils, such as degummed ~ soybean oil or degummed sunflower oil.
In the whole seed, phospholipids are present substan-tially in an hyd:ra-table form. ~iowever, during the process of crude oil extraction, and also in damaged seeds, hydra-table phospholipicls can be converted by various enzymes to non-hydra-table phospholipids. Crude oils may contain, therefore, varying proportions of hydratable and non-hydra-table phospholipids.
In rapeseed crushing, using the common prepress-sol-vent extraction process, expelled oils are found to contain about 0.3-1.0% phospholipids while solven-t extracted oils contain about 2.0-3.5% phospholipids. The typical crude rapeseed oi.l known to -the ar-t, obtained when blended in the usual proportion of 2 parts of expelled rapeseecl oil with 1 part of solvent e~tracted rapeseed oil, contains about 0.9-1.6% phospholipids.
I'he common industrial practice of degumming vegetable oils consists of treating crude or extracted oils with water or steam in order to hydrate the phospholipids, thereby rendering them insolube in the oils, in the form of an aqueous sludge phase. The latter, which is usually sepa-rated from the degummed oil by centrifugation, may be iso-lated and vacuum dried to yield a lecithin by-product.
Alternatively, the sludge may be incorporated into the ex-tracted meal, thereby increasiny the nutrient and energy value of the meal by-product. Frequently, only solvent ex-tracted oils are degummed prior to blending with expelledoil to produce a degummed oil. This practice evolved as it was found that phospholipids in solvent extracted oil are predominately of the hydratable type whereas phospho-lipids in expelled oil are predominately of the non-hydra-table type. However, the proportion of hydratable to non-hydratable phospholipids in either expelled oil or solvent ~a..~ 3 extracted oil is su~ect to considerable varia-tion depending on the quality of the processed seed and of processlny para-MeterS.
The non-hydratable phospholipids remaininy in degumm-ed oil are present mainly in the form of calcium and magne-sium salts of phosphatidic acid. Pr:ior to alkali refining, an acid is used to acldula-te these calcium and maynesium phosphatidates into hydratable phosphatidic acid which may -then be removed in the alkali reining stage.
According to the known ar-t, inorganic acids, such as phosphoric, hydrochloric, nitric, sulfuric and boric acid, have been examined as chemical degumming agents, as have organic acids, such as ace-tic, citric and oxalic acid.
Additionally, the use of mono-, di- and tri-chloroacetic acid and ace-tic anhydride have been examined.
In practice, phosphoric acid is most commonly used in the acid pre-treatment of degummed oils prior -to alkali refining. Following the acid pre-treatment, sodium hydr-oxide is mixed with the oil in a slight excess of -the stoichiometric requirement to neutralize -the added acid as well as the phosphatidic acids and free fatty acids pre-sent in the oil. The soapstock containing the sodium salts of these acids, as well as some entrained oil, is separated from the neutralized refined oil, usually by centrifugation.
It is customary for the soapstock to be acidulated to pro duce acidulated fatty acids, which are valued as an animal feedstuff, or for the soapstocks to be fully saponified, then acidulated, in order to recover fatty acid oils and glycerine.
The common practice of water degumming followed by acid pre-treatment and alkali refining of the degummed oil 1 1S78g~
has several dlsadvantacJes. Firs-tly, significant quan-tities of neutral oil are lost in each stage of the sequence of deyu~ming and refinincJ. In particular, the presence of phospholipids at -the reEining stage can result in an incre~
ased amount of an emulsion layer which may he difficult to separate and entrains neutral oil. In general, degummed oil containlng increased quantities of phospholipids requires higher proportions of phosphoric aci.d as a pre-treatment agent and, in turn, hi~her levels of sodium hydroxide in the alkali refining process and sulfuric acid in -the soap-spli-t-ting process. As a result, aqueous wastes from alkali refin-ing are increasingly con-taminated by organic and inoryanic waste materials. These materials can be significant envir-onmental pollutants and must frequently be removed from waste water prior to dischaxge.
As mentioned previously, the known art indicates that several alternative reagents have been examined for removing phospholipids from crude vegetable oils. Organic acids, in--cluding citric acid, have long been known to assist in the hydration of phospholipids including the non-hydratable types.
Acids, such as oxalic, acetic and citric acid, have been ex-amined as chemical degumming agents in order to reduce the environmental discharge of phosphates in waste waters.
Recently, a degumming process employing citric acid has been described in Canadian patent No. 1,060,0~1. This process involves the sequential addition of concentrated citric acid and wa-ter following a carefully controlled series of temperature adjustments. For example, it is pre~erred that citric acid be added to the oil at a temperature of at least 60C and more particularly within the range of 65 to 90C. Fur-thermore, it is also preferred that water be added ~ J'~o3 to the aci~-concli-tione~ oiI at a temperature below ~0C'., ~re-ferably at 2~ -to 35C. It is an essential requirement o~ the process that -the mixture o~ o.il, acid and water be maintained at a temperature below ~0C or at least 5 minutes before separating the aqueous sludge. Indeed, it is indicated that a temperature of 20 to 35C. for a period of at leas-t 30 min-utes is desirable before separatiny t:he aqueous sludge.
We have now :Eouncl, and herein lies our invention, -that a novel improved process which embodies a sirnplistic approach to temperature con-trol in a chemical degumminy process of crude vegetable oils can provide a degummed vegetable oil of a quality which has not hi-ther-to been readily obtainable.
We have now found that a crude veyetable oil, for ex-ample crude rapeseed oil, can be efficiently and economicall~
degummed to provide a degurnmed oil having a lower residual phosphorus content than that normally obtainable by water/
steam degumming and, moreover, with a residual phosphorus content generally less than about 50 parts per million (ppm) and frequently less than about 30 ppm by using an organic acid, such as citric acid, and water as the chemical degumm~
ing reagents provided that the process is maintained at a constant temperature of about 40C or higher and preferably within the range ol about 40 to about 75C.
Our invention as claimed herein is a novel improved process for degumming a crude vegetable oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed vege-table oil having a low residual phosphorus content which comprises maintaining the crude vegetable oil at a temperature of or above about 40C., adding an organic acid thereto under effective mixing con-ditions to substantially compl.ete reaction between the acid ~ ~57883 and -the phospholipic:~s, thereafter adding sufficient water under the effective mixing conditions to achieve subsequent hydration of -the acid-conditioned phospholipids and finally subjec-ting -the oil/acid/wa-ter mix-ture, at the s-tated temper-ature, to a separa-tion procedure to separate aqueous sludye therefrom and thereby provide the degunlmed vegetable oil having low residual phosphorus conterlt.
By operat.ion of this inventive process, it is possible to obtaln a degummed vegetable oil, and especially degummed rapeseed oil, having a residual phosphorus content of less than about 50 ppm and, often, to obtain such an oil having a ~ar-ticularly low residual phosphorus content of less than about 30 ppm.
The temperature to be maintained throughout the oper-ation of the process is preferably within the range of from about 40 to about 75C., more particularly from about 40 to about 65C and especially from about ~0 to about 55C.
A most effective temperature for operation of thc degumming process i5 within the range of from about 45 to about 55C.
The crude vegetable oil used as starting material may be any one of the oils commonly used as vegetable oils and may be, for example, rapeseed oil, soybean oil, rice bran oil, sunflower seed oil, safflower seed oil, sesame seed oil, flax(linseed) oil, grapeseed oil, groundnut oil, coconut oil, palm oil, cottonseed oil, maize(corn~ oil or palm kernel oil.
Ihe general applicability of our novel improved pro-cess for degumming a vegetable oil, in comparison with water degumming, is illustrated in Table I for a selection of crude vegetable oils including rapeseed oil, soybean oil, sunflower oil, safflower oil and linseed oil. Of these, rapeseed oil is an important vegetable oil which can now be produced in B~3;3 I ~ _ .
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The organic acid -to be usecl in the degumminy process is pre~erably ci-tric acid. It is generally added to -the crude oil, maintained within -the stat:ed temperature range, in the form of a coneentrated aqueous solution. A 50% con-centra-ted aqueous solution of citric acid has been found -to be advantageous. rrhe amoun-t of acid used in the process will generally be dependent upon the quality of the erude oil used as starting material, the me-thod by which sueh oil has been obtained from the original oil-bearing material and the number and amount of various undesirable impurities present in -the oil. We have found that ci-tric acid used in an amount of from about 0.05% to about 0.5% by weight based upon the weight of erude oil is usually adequate provided that there is thorough and effeetive mixing between the erude oil and -the eitrie acid in order to substanti.ally eom plete reaetion between the eitrie aeid and the phospholipids present in the erude oil. A preferred amount of eitric aeid is from about 0.1% to about 0.25% w/w based on erude oil and we have found that about 0.15% w/w of eitrie aeid is a par-tieularly efficient eoneentra-tion to be used.
After the crude oil has been treated with the organie aeid, sueh as eitrie aeid, and the phospholipids in the oil have thus beeome acid-conditioned, the proeess is eompleted by adding water to the oil/aeid mixture to aehieve hydration of the aeid-eonditioned phospholipids. A suitable amount of water to be added is within the range of from about 0.5%
to about 5% by weight based upon the weight of erude oil.
A preferred amount of water is within the range of from about 1% to about 3% by weight based upon the weignt of erude g ~ ~'3'o'~
oil and a most effec-tive amount of wa-ter is about 2~ w/w oE
crude oil.
The hydrated acid-conditioned phospholipids are not soluble in the thus treated oil and are therefore precipita-ted therefrom in the form of an aqueous sludge which can -then be separated from the residual deyummed oil. This separation may generally be carried out most efficiently and con~enient-ly by means o-f a centrifuye. The mix-ture of degummed oil and aqueous sludge is subjected to centrifuyation wi-th the result that the a~ueous sludge is separated from the oil and the oil thus obtained is a deyummecl vege-table oil having a low residual phosphorus content. In practice, it is often found that the degummed vegetable oil, and particularly de-gummed rapeseed oil, has a residual phosphorus content of less than about 50 ppm and frequently less than abou-t 30 ppm.
The inventive process as claimed herein also includes a novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil having a low residual phosphorus content which comprises maintaining the crude rapeseed oil at a temperature of or above 40C., adding a concentrated aqueous solution of citric acid there-to under effective mi~ing conditions to substantially com-plete reaction between the acid and the phospholipids, thereafter adding sufficient water under the effective mix-ing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/
acid/water mixture~ at the stated temperature, to a separa-tion procedure to separate aqueous sludge therefrom and provide the degummed rapeseed oil having low residual phos-phorus content. The degummed rapeseed oil thus obtained may have a resiclual phosp:horus content of less -than about 50 ppM
and even :Less -than abou-t 30 ppm.
In the drawing, which shows a flow shee-t ~iayram of a preferred embodiment for carrying out the process of the in-5 vention, crude vegetable oil is recei.ved from a crude oiltank 1 at a rneasured flow rate and is passed into a heat ex-changer 2 where it is either heated or cooled, as necessary, to the required temperature of about 40C or above 40C, preferably in the range of about 45 to about 55C. The oil, at the appropriate temperature, is then passed to the acid mix tank 3 and ci-tric acid is added to the oil in tank 3 at a controlled rate of 0.15% by weight based upon the weight of the oil, in -the form of a 50% concentrated aqueous solu-tion. The latter is stored in a citric acid holding tank 6.
The acid mix tank 3 is of a shape and size such that thor-ouyh and effective mixing conditions are available to en-sure substantially complete reaction between the citric acid and the phospholipids present in the crude oil. In practice, we have found that reaction times of about. 10 minutes or greater have been necessary for such complete reaction. The oil containing the acid-conditioned phospholipids is then passed into a water mix tank 4 and water is added to the oil at a rate of abou-t 1% to 3% by weight, preferably 2% by weight, based upon the weight of the crude oil. This water mix tank 4 is of a shape and size such that thorough and effective mixing takes place and an adequate reaction time allows complete hydration of the acid-conditioned phospho~
lipids to take place. It has been found, in practice, tha-t reaction times of about 20 minutes or greater have been necessary in order to effect complete hydration in the water mix tank 4. The mixture of hydrated phospholipids ~ 3 and deg-lmmed oil thus obtained i9 separa-ted by means of a centrifuge 5 which thereb~ provides an aqueous sludge and a degummed oil having a low residual phosphorus conten-t.
This phosphorus conte~t may be as low as 50 ppm or less and, frequen-tly, it may be as low as 30 ppm or less. Experience has shown that -the aqueous sludge so procluced is consider-ably more viscous than an aqueous sludge normally produced in a water or steam degumming process. As a result, the downstream physical handllng system for the aqueous slu~lge produced by the improved chemical degumminy according to the present inventive process must be designed in a manner to accommodate the physical nature of the aqueous sludge. In addition, it may be required to operate certain centrifuges at lower capacities than is customary in traditional water degumming processes.
The feasibility of the described process has been confirmed on an industrial scale at capacities of 4000 to 5000 kg of crude rapeseed oil per hour. Three examples of chemical degumming of crude rapeseed oils using the pro-cess of this invention (Experiments 14 to 16) are comparedin Table II with an example of water degumming wherein no citric acid is present (Experiment 13).
It is clear from these comparative experiments in Table II that more than 95% of the phosphorus in a crude rapeseed oil containing significant quantities of hydra-table and non-hydratable phospholipids can be removed by chemical degumming compared with only 78~ of the phosphorus in a similar crude rapeseed oil treated by a water degumm-ing process. In fact, it can be seen that crude rapeseed oils were chemically degummed by using citric acid and water to provide degummed rapeseed oils having a residual c~3 _ O ~ .
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The chemical degumming of prepress rapeseed oils con-taining mainly non-hydratable phospholipids (Experiments 17 ancl 18 in Table II) was somewhat less efficient in reducing phosphorus content than was chemical degumming of crude rapeseed oils consistiny of mixtures of prepxess oil and solvent oil, or of solvent oil alone, under similar degumm-ing condi-tions. These examples o:E chemical deyumming of sample prepress oils do not limit the technical nor prac-tical application of the inventive process to chemicallydegum prepress oils or similar such oils to a lower resid-ual phosphorus con-tent than would normally be achievable by water or steam degumming. Furthermore, these examples also do not ~egate the feasibility of chemically degumming a crude prepress oil or similar such oils to provide de-gummed oils containing a low resldual phosphorus content, for example less than about 50 ppm of phosphorus, according to the described inventive process provided such oils con-tain significant quantities of hydratable phospholipids.
To test the effect of citric acid rate on the chemi-cal degumming of crude rapeseed oils as produced in a pre-press/solvent extraction process, several additional chem-ical degumming experiments were conducted, the results of which are compared in Table III.
Comparing the results obtained from experiments l9 to 29 as shown in Table III, it can clearly be seen that several crude rapeseed oils containing phosphorus levels of the order of from 380 to 540 ppm have been chemically degummed in a satisfactory manner, over the temperature range of 45 to 75C., using citric acid addition rates ~I h-- o (~1 ~D o a~ o~ o o ~ ~I r`
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X ~ . . . . _ ~ v __ J~3 over the range of from 0.L~ to O . 25~ by welght bas~d upon the weigh-t of crude oil. The degur~led rapeseed oils thus obtained had a residual phosphorus con-ten-t of less -than 50 ppm and, lndeed, it is par-ticularly notable that -the deyummed rapeseed oils ob-~ained in Experiments 21, 22, 2~, 27 and 28 had resldual phosphorus con-tents within the extremely low range of from 6 to 14 ppm.
These results demonstrate that an excess of citric acid does not detract from -the prac-t:ical operation of our inventive process. However, it would be obvious to one skilled in the art that a minimum concentration of citric acid is required for the inventive process, the minimum being dependent to some extent on the composition of the phospholipids present in the crude oil used as s-tarting material.
It will be appreciated by one skilled in the art of refining crude vegetable oils ~hat, although our inventive process has been illustrated and exempliied in detail by reference to rapeseed oil, which is an important commercial product, it is also possible to apply our inventive process to other crude vegetable oils. Some comparative examples of such alternative vegetable oils are mentioned in the foregoing description and in Table I. Operation of our process produces corresponding degummed vegetable oils hav-ing low residual phosphorus contents. The degummed vege-table oils frequently have a residual phosphorus content of less than about 50 ppm and, in some instances, they have a residual phosphorus content of less than about 30 ppm.
Such residual phosphorus con-tents are substantially lower than those obtainable by water degumming of the identical crude oils.
~ ~ a ~ 3 ~ part from the use of an organic acid, such as citric acid, in the range of Erom about 0.05% to 0.5~ w/w of crude oil, preferably 0.1~ to 0.25% w/w of crude oil, and ~ater, in the range of 0.5~O -to 5O w/w of crude oil, preferably 1%
to 3~O w/w of crude oil, to achieve acid-conditioning and hy-dra-tion of the phospholipids in the crude oils, -the funda-mental and essen-tial feature of our :inventive process is the use of a constant -tempera-ture within a specifi.ed range throu-ghout the operation of the process. This collstan-t temperature may be as low as abou-t 40C. but it :Ls desirably within the range of from abou-t 40 to about 75C. and preferably within the range of from about 45 to about 55C.
We have found tha-t operation of this inventive process using crude rapeseed oil as starting material at a tempera-ture of about 45 -to about 55C. provides degummed rapeseed oil having a residual phosphorus content of less than about 50 ppm and, more desirably, less than 30 ppm.
Thus, the process as claimed herein, is furthermore a process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 50 ppm of residual phosphorus which comprises main-taining said crude rapeseed oil at a temperature of about ~5 to 55C., adding citric acid in the form of a 50% w/w aqueous concen-trated solution -thereto at a rate of about 0.15% citric acid by weight of the oil under effective mix-ing conditions to substantially complete reaction between said acid and said phospholipids, thereafter adding suffi-cient water at a rate of about 2% by weight of the oil under said effective mixing conditions to achieve subsequent hydr-ation of the acid-conditioned phospholipids and finally sub-~ 157883 jecting the oil/acid/water mixture, within -the sta-ted tempera-ture range, to a separation procedure by centrifugation to separa-te aqueous sludge -therefrom and provide -the degummed rapeseed oil havincJ a residual phosphorus con-tent of less than about 50 ppm.
Upon experimentation, we have found -that degummed rape-seed oil having a residual phosphorus con-tent of less than 30 ppm has the potential to ~e~steam refined in a process similar to tha-t commonly used for palm oil, thereby producing a finished rapeseed oil similar in quali.ty -to a refined, bleached and deodourized rapeseed oil produced in a tradi-tional alkali refining process.
Claims (77)
1. A novel improved process for degumming a crude vegetable oil containing gums in the form of hydratable and non-hydratable phospholipids to provide degummed vegetable oil having a low residual phosphorus content which comprises maintaining said crude vegetable oil at a temperature of or above about 40°C., adding citric acid thereto under effective mixing conditions to substantially complete reaction between said citric acid and said phospholipids, thereafter adding sufficient water under said effective mixing conditions to achieve subsequent hydration of the acid-conditioned phos-pholipids and finally subjecting the oil/acid/water mixture, at the stated temperature, to a separation procedure to se-parate aqueous sludge therefrom and provide said degummed vegetable oil having low residual phosphorus content.
2. The process of claim 1 wherein the degummed oil thus obtained has a residual phosphorus content of less than about 50 ppm.
3. The process of claim 1 wherein the degummed oil thus obtained has a residual phosphorus content of less than about 30 ppm.
4. The process of claim 1 wherein the temperature is within the range of from about 40° to about 75°C.
5. The process of claim 1 wherein the temperature is within the range of from about 40° to about 65°C.
6. The process of claim 1 wherein the temperature is within the range of from about 40° to about 55°C.
7. The process of claim 1 wherein the temperature is within the range of from about 45° to about 55°C.
8. The process of claim 1 wherein the crude vegetable oil is selected from rapeseed oil, soybean oil, rice bran oil, sunflower oil, safflower oil, sesame oil, flax (linseed) oil, grapeseed oil, groundnut oil, coconut oil, palm oil, cotton-seed oil, maize (corn) oil and palm kernel oil.
9. The process of claim 1 wherein the crude vegetable oil is selected from rapeseed oil, soybean oil, sunflower oil, safflower oil and flax (linseed) oil.
10. The process of claim 1 wherein the crude vegetable oil is rapeseed oil.
11. The process of claim 1 wherein the citric acid is in the form of a concentrated aqueous solution.
12. The process of claim 1 wherein the citric acid is in the form of a 50% concentrated aqueous solution.
13. The process of claim 1 wherein the citric acid is used in an amount of from about 0.05% to about 0.5% of acid by weight of crude oil.
14. The process of claim 1 wherein the citric acid is used in an amount of from about 0.1% to about 0.25% of acid by weight of crude oil.
15. The process of claim 1 wherein the citric acid is used in an amount of about 0.25% of acid by weight of crude oil.
16. The process of claim 1 wherein the citric acid is used in an amount of about 0.15% of acid by weight of crude oil.
17. The process of claim 1 wherein the amount of water added to achieve subsequent hydration of the acid-con-ditioned phospholipids is within the range of from about 0.5%
to about 5% by weight of crude oil.
to about 5% by weight of crude oil.
18. The process of claim 17 wherein the amount of water added is within the range of from about 1% to about 3%
by weight of crude oil.
by weight of crude oil.
19. The process of claim 17 wherein the amount of water added is about 2% by weight of crude oil.
20. The process of claim 1 wherein the separation procedure is carried out by means of centrifugation.
21. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil having a low residual phosphorus content which comprises maintaining said crude rapeseed oil at a temperature of or above 40°C., adding a concentrated aqueous solution of cit-ric acid thereto under effective mixing conditions to sub-stantially complete reaction between said acid and said phospholipids, thereafter adding sufficient water under said effective mixing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, at the stated temperature, to a separation procedure to separate aqueous sludge therefrom and provide the degummed rapeseed oil having a low residual phosphorus content.
22. The process of claim 21 wherein the degummed rapeseed oil thus obtained has a residual phosphorus content of less than about 50 ppm.
23. The process of claim 21 wherein the degummed rape-seed oil thus obtained has a residual phosphorus content of less than about 30 ppm.
24. The process of claim 21 wherein the temperature is within the range of from about 40° to about 75°C.
25. The process of claim 21 wherein the temperature is within the range of from about 40° to about 65°C.
26. The process of claim 21 wherein the temperature is within the range of from about 40° to about 55°C.
27. The process of claim 21 wherein the temperature is within the range of from about 45° to about 55°C.
28. The process of claim 21 wherein the concentrated aqueous solution of citric acid contains about 50% of citric acid.
29. The process of claim 21 wherein the citric acid is used in an amount of from about 0.05% to about 0.5% of acid by weight of crude oil.
30. The process of claim 21 wherein the citric acid is used in an amount of from about 0.1% to about 0.25% of acid by weight of crude oil.
31. The process of claim 21 wherein the citric acid is used in an amount of about 0.15% of acid by weight of crude oil.
32. The process of claim 21 wherein the citric acid is used in an amount of about 0.25% of acid by weight of crude oil.
33. The process of claim 21 wherein the amount of water added to achieve subsequent hydration of the acid-conditioned phospholipids is within the range of from about 0.5% to about 5% by weight of crude oil.
34. The process of claim 33 wherein the amount of water added is within the range of from about 1% to about 3%
by weight of crude oil.
by weight of crude oil.
35. The process of claim 33 wherein the amount of water added is about 2% by weight of crude oil.
36. The process of claim 21 wherein the separation procedure is carried out by means of centrifugation.
37. The process of claim 21 wherein the citric acid is mixed within the crude oil under effective mixing condi-tions for a minimum period of about 10 minutes.
38. The process of claim 21 wherein the added water is mixed with the crude oil/citric acid mixture under effec-tive mixing conditions for a minimum period of about 20 minutes.
39. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil having a low residual phosphorus content which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50%
w/w aqueous concentrated solution thereto at a rate of about 0.1% to about 0.25% citric acid by weight of the oil under effective mixing conditions to substantially complete reac-tion between said acid and said phospholipids, thereafter adding sufficient water at a rate of from about 1% to about 3% by weight of the oil under said effective mixing condi-tions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mix-ture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge there-from and provide the degummed rapeseed oil.
w/w aqueous concentrated solution thereto at a rate of about 0.1% to about 0.25% citric acid by weight of the oil under effective mixing conditions to substantially complete reac-tion between said acid and said phospholipids, thereafter adding sufficient water at a rate of from about 1% to about 3% by weight of the oil under said effective mixing condi-tions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mix-ture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge there-from and provide the degummed rapeseed oil.
40. A novel improved process for degumming crude rape-seed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil having a low residual phosphorus content which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50% w/w aqueous concentrated solution thereto at a rate of about 0.15%
citric acid by weight of the oil under effective mixing con-ditions to substantially complete reaction between said acid and said phospholipids, thereafter adding sufficient water at a rate of about 2% by weight of the oil under said effec-tive mixing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge therefrom and provide the degummed rapeseed oil.
citric acid by weight of the oil under effective mixing con-ditions to substantially complete reaction between said acid and said phospholipids, thereafter adding sufficient water at a rate of about 2% by weight of the oil under said effec-tive mixing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge therefrom and provide the degummed rapeseed oil.
41. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 50 ppm of residual phosphorus which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50% w/w aqueous concentrated solution thereto at a rate of about 0.1% to about 0.25% citric acid by weight of the oil under effective mixing conditions to substantially complete reaction between said acid and said phospholipids, thereafter adding sufficient water at a rate of about ]% to about 3% by weight of the oil under said effective mixing conditions to achieve subsequent hydration of the acid-con-ditioned phospholipids and finally subjecting the oil/acid/-water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge therefrom and provide the degummed rapeseed oil.
42. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 50 ppm of residual phosphorus which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50% w/w aqueous concentrated solution thereto at a rate of about 0.15% citric acid by weight of the oil under effective mixing conditions to substantially complete reac-tion between said acid and said phospholipids, thereafter adding sufficient water at a rate of about 2% by weight to the oil under said effective mixing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge therefrom and provide the degummed rapeseed oil.
43. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 30 ppm of residual phosphorus which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50% w/w aqueous concentrated solution thereto at a rate of about 0.1% to about 0.25% citric acid by weight of the oil under effective mixing conditions to substantially complete reaction between said acid and said phospholipids, thereafter adding sufficient water at a rate of about 1% to about 3% by weight of the oil under said effective mixing conditions to achieve subsequent hydration of the acid-condi-tioned phospholipids and finally subjecting the oil/acid/water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge there-from and provide the degummed rapeseed oil.
44. A novel improved process for degumming crude rapeseed oil containing gums in the form of hydratable and non-hydratable phospholipids to provide a degummed rapeseed oil containing less than about 30 ppm of residual phosphorus which comprises maintaining said crude rapeseed oil at a temperature of about 45° to 55°C., adding citric acid in the form of a 50% w/w aqueous concentrated solution thereto at a rate of about 0.15% citric acid by weight of the oil under effective mixing conditions to substantially complete reac-tion between said acid and said phospholipids, thereafter adding sufficient water at a rate of about 2% by weight of the oil under said effective mixing conditions to achieve subsequent hydration of the acid-conditioned phospholipids and finally subjecting the oil/acid/water mixture, within the stated temperature range, to a separation procedure by centrifugation to separate aqueous sludge therefrom and pro-vide the degummed rapeseed oil.
45. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 1.
46. A degummed vegetable oil having a residual phos-phorus content of less than about 50 ppm, when prepared by the process of claim 2.
47. A degummed vegetable oil having a residual phos-phorus content of less than about 30 ppm, when prepared by the process of claim 3.
48. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 4, 5 or 6.
49. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 7.
50. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim or 9.
51. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 10.
52. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 11 or 12.
53. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 13 or 14.
54. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 15.
55. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 16.
56. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 17 or 18.
57. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 19.
58. A degummed vegetable oil having a low residual phosphorus content, when prepared by the process of claim 20.
59. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 21.
60. A degummed rapeseed oil having a residual phos-phorus content of less than about 50 ppm, when prepared by the process of claim 22.
61. A degummed rapeseed oil having a residual phos-phorus content of less than about 30 ppm, when prepared by the process of claim 23.
62. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 24, 25 or 26.
63. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 27.
64. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 28, 29 or 30.
65. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 31.
66. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 32.
67. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 33 or 34.
68. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 35.
69. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 36.
70. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 37.
71. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 38.
72. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 39.
73. A degummed rapeseed oil having a low residual phosphorus content, when prepared by the process of claim 40.
74. A degummed rapeseed oil having a residual phos-phorus content of less than about 50 ppm, when prepared by the process of claim 41.
75. A degummed rapeseed oil having a residual phos-phorus content of less than about 50 ppm, when prepared by the process of claim 42.
76. A degummed rapeseed oil having a residual phos-phorus content of less than about 30 ppm, when prepared by the process of claim 43.
77. A degummed rapeseed oil having a residual phos-phorus content of less than about 30 ppm, when prepared by the process of claim 44.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000369279A CA1157883A (en) | 1981-01-26 | 1981-01-26 | Chemical degumming of crude vegetable oils |
| JP57009020A JPS57177098A (en) | 1981-01-26 | 1982-01-25 | Method of degumming vegetable crude oils |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000369279A CA1157883A (en) | 1981-01-26 | 1981-01-26 | Chemical degumming of crude vegetable oils |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1157883A true CA1157883A (en) | 1983-11-29 |
Family
ID=4119009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000369279A Expired CA1157883A (en) | 1981-01-26 | 1981-01-26 | Chemical degumming of crude vegetable oils |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS57177098A (en) |
| CA (1) | CA1157883A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0269277A2 (en) * | 1986-11-13 | 1988-06-01 | The Cambrian Engineering Group Limited | Process for degumming triglyceride oils |
| WO2012049232A1 (en) | 2010-10-13 | 2012-04-19 | Süd-Chemie AG | Method for removing compounds containing phosphorus from compositions containing triglyceride |
| DE102010055969A1 (en) | 2010-12-23 | 2012-06-28 | Süd-Chemie AG | Process for the purification of organic liquids |
| CN111349514A (en) * | 2020-03-30 | 2020-06-30 | 益海嘉里(岳阳)粮油工业有限公司 | Method for degumming and refining rapeseed oil based on deep acid method |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07116463B2 (en) * | 1992-06-19 | 1995-12-13 | 日清製油株式会社 | Method of producing refined sesame oil |
| JP5535461B2 (en) * | 2008-09-08 | 2014-07-02 | 日清オイリオグループ株式会社 | Oil and fat manufacturing method |
| ES2490619T3 (en) * | 2010-11-08 | 2014-09-04 | Neste Oil Oyj | Lipid extraction method from biomass |
-
1981
- 1981-01-26 CA CA000369279A patent/CA1157883A/en not_active Expired
-
1982
- 1982-01-25 JP JP57009020A patent/JPS57177098A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0269277A2 (en) * | 1986-11-13 | 1988-06-01 | The Cambrian Engineering Group Limited | Process for degumming triglyceride oils |
| EP0269277A3 (en) * | 1986-11-13 | 1988-07-06 | The Cambrian Engineering Group Limited | Process for degumming triglyceride oils |
| WO2012049232A1 (en) | 2010-10-13 | 2012-04-19 | Süd-Chemie AG | Method for removing compounds containing phosphorus from compositions containing triglyceride |
| DE102010048367A1 (en) | 2010-10-13 | 2012-04-19 | Süd-Chemie AG | Process for removing phosphorus-containing compounds from triglyceride-containing compositions |
| US8987487B2 (en) | 2010-10-13 | 2015-03-24 | Süd—Chemie IP GmbH & Co. KG | Method for removing phosphorus-containing compounds from triglyceride-containing compositions |
| DE102010055969A1 (en) | 2010-12-23 | 2012-06-28 | Süd-Chemie AG | Process for the purification of organic liquids |
| CN111349514A (en) * | 2020-03-30 | 2020-06-30 | 益海嘉里(岳阳)粮油工业有限公司 | Method for degumming and refining rapeseed oil based on deep acid method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57177098A (en) | 1982-10-30 |
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