US3059009A

US3059009A - Fat crystallization process

Info

Publication number: US3059009A
Application number: US139607A
Authority: US
Inventors: Dieter F Schmid; Fredric J Baur
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1961-09-21
Filing date: 1961-09-21
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16
Also published as: GB1005543A

Description

United rates Patent 3,059,009 FAT CRYSTALLIZATION PROCESS Dieter F. Schmid, Heidelberg, Germany, and Fredric .I.

Baur, Cincinnati, Ohio, assignors to The Procter &

glaimble Company, Cincinnati, Ohio, a corporation of o No Drawing. Filed Sept. 21, 1961, Ser. No. 139,607 7 Claims. (Cl. 260-428) This invention relates to an improved crystallization process. More particularly, it relates to the addition of certain crystal modifying agents to glyceride oils containing fatty materials which are insoluble in the oils, whereby separation of the insoluble fatty materials from the oils is facilitated.

A large amount of vegetable glyceride oil is used as salad oil. Such oils can serve as a base for various liquid salad dressings, providing an oily coating for salad ingredients. They are also used in mayonnaise emulsions. Both salad oils and mayonnaise are usually kept under refrigeration by the housewife. At temperatures of about 40 F. or lower, fatty materials will deposit out of many salad oils, causing them to have a cloudy appearance. In mayonnaise, such crystal formation tends to break the emulsion, causing separation of fatty material from the aqueous portion.

If soybean oil is used as a salad oil it tends to develop a characteristic beany odor and flavor. Even when it has been rendered completely odorless and flavorless by high-temperature steam deodorization, the characteristic odor and flavor will return, in part, at least, due to the linolenic acid content of the oil.

It has been proposed that the stability of soybean oil against odor and flavor reversion can be increased by hydrogenation. However, hydrogenation decreases the unsaturation of unsaturated component fatty acids and also converts the unsaturated acids to higher-melting and less-soluble isomers. The oil must then be winterized by a process including cooling and subsequent separation of insoluble glycerides to remove materials which will solidify when the oil is refrigerated, and thereby cause undesirable salad oil performance and appearance. Other oils such as cottonseed oil are given a similar Winterizing treatment. Insoluble fatty materials in oils such as corn oils are also removed by a cooling step, followed by a separation step.

Another important use of glyceride oils is in the paint industry. Oils of particular interest are the so-called drying oils which form protective coatings because of the ability of these oils to polymerize or dry after they have been applied, thereby forming tough, adherent, impervious and abrasion-resistant films.

It is generally believed that the film-forming properties of drying oils are related to their degree of unsaturation, andthat the films are formed by polymerization of double bonds present in unsaturated oils. It is highly desirable, therefore, that oils suitable for use as drying oils contain a large amount of triunsaturated glycerides, and relatively few trisaturated glycerides or mixed saturated-unsaturated triglycerides.

U.S. Patents 2,442,531 and 2,442,533, issued to E. W. Eckey on June 1, 1948, disclose the directed rearrangement of triglycerides. By means of the process disclosed in these patents a substantial portion of mixed saturatedunsaturated triglycerides is rearranged to form a larger proportion of highly saturated glycerides and highly unsaturated glycerides. The more saturated glycerides in crystalline form are then separated from the rearranged and mixture, leaving an unsaturated oil very suitable for use as a drying oil.

Special coating fats are required for coating of candies. These fats must have a high melting point so that they will not be greasy at normal room temperatures. However, these fats must also melt in the mouth when the candy is eaten, and thus the presence of fats melting at too high temperatures are undesirable. When oils such as hydrogenated palm kernel oil, and palm oil, either hydrogenated or unhydrogenated, are to be used for this purpose, it may be desirable to separate out highlysaturated materials which would produce a waxy taste in the mouth. Suitable confectioners fats can also be formed from the more saturated portions of directed rearranged triglycerides.

At times it would be desirable to use palm oil as a major constituent of a margarine oil. In certain geographic locations palm oil is cheaper than other oils, and a supply of palm oil may be more readily available than a supply of some other oil. It has been found that the content of high-melting insoluble fats in palm oil, at a temperature of 92 F., is too high to produce a satisfactory margarine, since these insoluble fats will impart a waxy taste in the mouth during eating. Separation of the insoluble fats from the palm oil would increase its utility as a margarine constituent.

One of the main problems encountered in the separation of insoluble fatty materials from glyceride oils has been the fact that the insoluble fatty materials entrain a large amount of glyceride oil. In addition, conventional separation procedures are very slow.

It has now been found that by the process of this invention the separation of insoluble fatty materials from liquid glyceride oils is greatly facilitated, thereby permitting the recovery of a much larger amount of liquid oil than has heretofore been possible. In addition, the rate of separation is greatly increased. As used herein the term insoluole fatty materials is intended to include materials which dissolve in oils at elevated temperatures and which will precipitate out of solution as the oils are cooled and allowed to stand.

It is therefore an object of this invention to provide a process for modifying insoluble fatty materials in glyceride oils whereby the subsequent separation of the fatty materials is greatly facilitated.

It is a further object of this invention to provide an improved process for making a salad oil.

Another object is to provide an improved method of making a drying oil.

Yet another object is to provide a method of making confectioners fats which have good eating quality.

Other objects and advantageous features will be app-arent from the following detailed description.

In general, the process of this invention comprises the steps of dissolving in a glyceride oil containing insoluble fatty material, at a temperature at which substantially all of said fatty material is in solution in said glyceride oil, from about 0.001% to 0.5%, by weight of oil, of sucrose esterfied with an average of from about 15% to of saturated fatty acid having from 12 to 22 carbon atoms in the alkyl chain and from 0 to unsaturated fatty acid having from 12 to 22 carbon atoms in the alkyl chain; cooling the glyceride oil to a temperature at which insoluble fatty material comes out of solution; and separating the insoluble fatty material from the oil. The degree of esterification should be such that the ester contains an average of not more than about 5 unesterified hydroxyl groups per sucrose molecule. Esters contain- ,such as pyridine, amides, and sulfoxides.

ing more than that number of unesterified hydroxyl groups will be too insoluble to modify the fatty materials in the desired manner.

The sucrose ester exerts a modifying effect on the insoluble material so that it comes out of solution in the form of large crystalline aggregates. These entrain a smaller amount of liquid fatty glycerides during separation than do crystals formed in the absence of the ester.

The process of this invention is generally applicable to any glyceride oils which contain fatty materials which will dissolve in the oils at elevated temperatures and which will crystallize out of solution when the oils are subsequently cooled and allowed to stand. For example, the removal of insoluble fatty materials from oils which are conventionally winterized to form salad oils, such as cottonseed oil, hydrogenated soybean oil, and corn oil is greatly facilitated. The process can be applied to oils such as palm oil and palm kernel oil, either hydrogenated orunhydrogenated to form improved margarine oils or confectioners fats.

Directed rearranged triglycerides can also be processed by this invention. Preferably the directed rearrangement iscarried out as described in US. Patent 2,442,531, issued June 1, 1948, in which triglyceride oils are contacted with a low-temperature molecular rearrangement catalyst at such a temperature that the more highly saturated triglycides are precipitated as they are formed during the rearrangement of the glycerides in the oil. A list of suitable rearrangement catalysts is set forth in the aforementioned U.S. Patent 2,442,531. However, it is to beunderstood that other suitable rearrangement catalysts and operating conditions can be used. As used herein the term directed rearrangement is intended to denote a molecular rearrangement process directed for a greater tion of sucrose with fatty acids, fatty acidanhydrides, or 'fatty acid halides. They can also be prepared by interesterification of sucrose with fatty acid esters of other polyhydric compounds in the presence of suitable solvents Other methods of forming these esters can be used, and it is to be understood that the invention is not limited to any specific method of making the esters.

It is preferred that the oils to be processed be heated to a temperature at which substantially all of the insoluble fatty material is in liquid form prior to slowly cooling the oil in which is dissolved the sucrose ester. The ester can be added prior to or after heating. The exact conditions for cooling will vary with the amount of oil in the batch and the amount of insoluble fatty material, but the optimum cooling conditions can be determined by those skilled in conventional oil graining procedure.

The insoluble fatty materials are conveniently separated by conventional filtration procedures, but other methods of separation such as centrifuging, can be used.

The improved results which can be achieved by the process of this invention are clearly illustrated by the following examples:

EXAMPLE I 250 g. of refined and bleached soybean oil, hydrogenated to an iodine value of 105, was mixed in a container with 0.1%, by weightof oil, of a vegetable oil ester of sucrose.

The vegetable oil ester was prepared by mixing togeether 300 g. of sucrose, 500 g. of a mixture of 80% soybean oil and 20% cottonseed oil hydrogenated to an iodine value of 76, and 1250 ml. of pyridine, and heating the mixture to 240 F. Then 100 ml. of a solution containing 9 g. of sodium methoxide suspended in xylene was added as a catalyst and stirred for 4 hours. The catalyst Was inactivated with acetic acid and the pyridine was substantially all removed by vacuum distillation.

The distillation residue was taken up in 700 ml. of a 4 to 1 mixture of ethyl acetate and n-butanol, and waterwashed. The Water-washed fatty products were recovered by evaporating the ethyl acetate-n-bntanol solvent under a stream of nitrogen and using a steam bath. The fatty acid content of the product, as analyzed by ultraviolet spectrometry, was approximately as follows:

Percent Total saturated (approximately half palmitic acid and half stearic acid) 16.9 Octadecenoic acid 75.0 Octadecadienoic acid 7.9 Octadecatrienoic id V 0.2

An average of about 3 of the hydroxyl groups of the sucrose were esterified.

The mixture of oil and additive was heated to F. for one hour. It was then placed for three days in a room held at a temperature of 40 F. The resulting mixture of liquid and solid glycerides which had formed was filtered through a Buchner funnel using filter paper and suction. The following measurements were recorded of the total amount of oil passing through the filter at various time intervals, as compared with a similar sample containing no additive:

V Filtrate Volume (00.)

Time (min.)

Vegetable Oil Ester 0t Sucrose No Additive EXAMPLE n An ester of sucrose containing both saturated and unsaturated long-chain fatty acids was dissolved in a onepound sample of refined cottonseed oil at a level of 0.005% by weight. The fatty acid composition of the ester was approximately as follows:

Percent Total saturated (approximately half palmitic 19.0 79.5 1.4 Trace and half steaiic acids) Octadecenoic acid Octadecadienoic acid Octadecatrienoic a id About one-half of the hydroxyl groups of the sucrose were esterified. This oil, and also a sample of the oil without ester, were heated to a temperature of 140 F.

with stirring. Thejsamples were cooled gradually to 60 F. and held at that temperature for about 24 hours. They were then cooled slowly to a'temperature of 45 F. and held at that temperature for about 24 hours until crystallization appeared to be substantially complete. 'Each sample was vacuum filtered using, a Buchner fun- ;nel and filter paper. The filtration was continued until and then holding it as 40 F. for 3 days.

the filter cake broke. The filtrates were weighed and the yield of oil calculated. These data were as follows:

Filtration Yield Yield of Amt. Additive (Percent) Time Oil (gm.) Oil in) (Percent) None 487. 5 355 78. 5 0.005 312.0 367 80. 7

EXAMPLE III Filtration Yield of Yield of Amt. Additive (Percent) Time Oil (gm.) Oil (min) (Percent) None 12. 5 320 70. 5 0.005 l2. 5 349 76. 9

EXAMPLE IV Similar experiments were performed as in Examples 11 and II except that the ester was sucrose esterified with an average of about 6 palmitic and 3 oleic acid groups per molecule of sucrose. Filtration data on these samples were as follows:

Amt. of Filtration Yield 0! Yield of Oil Additive Time Oil Oil (Percent) (min.) (gm) (Percent) None 487. 5 355 78. 5 Cottonseed 0.005 201. 0 359 80. 2 0.01--." 240. 3 372 83. 3 Hydrogenated soybean oil.-- {None 12. 5 320 70. 5 0.005 7. 5 310 68.3

In the case of the soybean oil, although there was only a slightly smaller yield, the filtration time is greatly decreased. The substitution of esters using other combinations of saturated and unsaturated fatty acids having from 12 to 22 carbon atoms in the alkyl chain, as hereinbefore set forth, and also their use in other oils such as corn oil, and directed rearranged glyceride oils, will provide comparable results on filtration.

The practice of the process of this invention in the removal of fatty materials which are insoluble in glyceride oils at higher temperatures is illustrated by the following example:

EXAMPLE V Soybean oil was hydrogenated to an iodine value of 105 and winterized by holding it at 50 F. for 2 weeks, The oil was then vacuum filtered. A mixture was formed containing 95% of the clear oil filtrate and 5% of a saturated triglyceride containing about 2 palmitic acid groups and 1 stearic acid group per molecule. This saturated triglyceride had an iodine value of 0.012. To the mixture was added 0.1%, by weight, of the sucrose ester of Example I. 250 gm. samples of the oil mixture with and without added ester were heated to 140 F. for one hour to destroy all crystal nuclei and then cooled to 80 F. and held at that temperature for 3 days to permit crystals to form. The resulting mixtures of insoluble fatty material and glyceride oil were filtered through a Buchner funnel using filter paper and vacuum. The following measurements were recorded of the total amounts of oil passing through the filters at various time intervals.

1 N 0t measured.

Comparable results will be achieved by substitution in the foregoing example of oils such as directed rearranged glyceride oils, hydrogenated vegetable oils and other glyceride oils containing fatty materials insoluble in these oils at higher temperatures.

Although it is to be understood that the invention is not to be limited by any theory, it is believed that esters suitable for improving the filtration of oils for the purpose of separating insoluble fats from oils should contain a substrate-similar and a substrate-dissimilar moiety in the molecule. In the case of the aforementioned systems fatty acid chains in the fats and in the sucrose ester are similar. The sucrose portion of the additive represents a polyhydric compound which is dissimilar from that of the fats.

It is also believed that it is important that materials added as filtration aids bear some relation in melting point and/ or solubility to the fats which are to be separated by filtration. These aids should be made with fatty acids having neither too high nor too low a melting point, so that the modifier will have a tendency to deposit on the incipient crystal nuclei as they are formed, thereby modifying the fat crystals. This results in the formation of crystal aggregates (around a crystallization center) which are compact and not feathery and are more easily filtered.

Further, it is believed that if the additive has too high a melting point of too low a solubility in the oil, nuclei of additive will tend to form before the fat nuclei are formed, and the additive may act as a nucleating agent for the fat, forming more nuclei than would normally appear in the fat. As a result the fat crystal aggregates will be more numerous and filtration will be more difficult.

Although specific examples have been given to illustrate the invention, it is to be understood that the invention is not to be limited to these examples, and that variations in the processing condiitons which will suggest themselves to those skilled in the art are intended to be witln'n the scope of the invention. It will further be appreciated that sucrose esters used in commercial practice usually will be a mixture of various esters and that the specified proportions of fatty acids represent average values for such mixtures.

This is a continuation-in-part of application Serial No. 845,642, filed October 12, 1959.

What is claimed is:

1. The method of separating insoluble fatty material from glyceride oil which comprises the steps of dissolving in said glyceride oil, at a temperature at which substantially all of said fatty material is in solution, from about 0.001% to 0.5%, by weight of oil, of sucrose esterified with an average of from about 15% to saturated fatty acid having from 12 to 22 carbon atoms in the alkyl chain and from 0 to of unsaturated fatty acid having from 12 to 22 carbon atoms in the alkyl chain; said ester containing not more than 5 unesterified hydroxyl groups; cooling the glyceride oil to a temperature at which insoluble fatty material comes out of solution; and separating the insoluble fatty material from the oil.

2. The method according to claim 1 wherein the sucrose is esterified with a mixture of fatty acids comprising 7 essentially from 8% to 16% palmitic acid, and 5% to 15% stearic acid, the total combined saturated fatty acid content being from about 15% to 27%, and the balance of the fatty acids being essentially from 59% to 76% octadecenoic acids and 3% to 9% octadecadienoic acids. 3. The method according to claim 1 wherein a solution of sucrose ester in oil is heated to a temperature at which substantially all of the insoluble fatty material is dis solved, and the mixture is thereafter slowly cooled to a temperature at which fatty crystals will form.

4. The method according to claim 1 wherein the oil is V heated to a temperature at which substantially all of the insoluble fatty material is dissolved, the sucrose ester is dissolved in said heated oil, and the resulting mixture is slowly cooled to a temperature at which fatty crystals will form.

5. The method according to claim 1 wherein the oil is cottonseed oil.

6. The method according to claim 1 wherein the oil is hydrogenated soybean oil.

7. The method according to claim '1 wherein the oil is -a directed rearranged glyceride oil.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No, 3,059,009 October 16 1962 Dieter F, Schmid et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 lines 6'? and 68 for "togeether" read together column 6,, in the table last column opposite 4" for read (l) line 51 for "condiitons" read conditions Signed and sealed this 30th day of April 1963a (SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents

Claims

1. THE METHOD OF SEPARATING INSOLUBLE FATTY MATERIAL FROM GLYCERIDE OIL WHICH COMPRISES THE STEPS OF DISSOLVING IN SAID GLYCERIDE OIL, AT A TEMPERATURE AT WHICH SUBSTANTIALLY ALL OF SAID FATTY MATERIAL IS IN SOLUTION, FROM ABOUT 0.001%TO 0.5%, BY WEIGHT OF OIL, OF SUCROSE ESTERIFIED WITH AN AVERAGE OF FROM ABOUT 15% TO 80% SATURATEDD FATTY ACID HAVING FROM 12 TO 22 CARBON ATOMS, IN THE ALKYL CHAIN AND FROM 0 TO 85% OF UNSATURATED FATTY ACID HAVING FROM 12 TO 22 CARBON ATOMS IN THE ALKYL CHAIN; SAID ESTER CONTAINING NOT MORE THAN 5 UNESTERIFIED HYDROXYL GROUPS; COOLING THE GLYCERIDE OIL TO A TEMPERATURE AT WHICH INSOLUBLE FATTY MATERIAL COMES OUT OF SOLUTION; AND SEPARATING THE INSOLUBLE FATTY MATERIAL FROM THE OIL.