US2282810A - Method for stabilizing oils - Google Patents

Description

Patented May 1 Z, 1942 UNITED STATES 2,282,810 METHOD FOR STABILIZING OILS Sidney Masher, New'Y ork, N. Y., asslgnor to Musher Foundation Incorporated, New York, N. Y., a corporation of New York No Drawing. Application July 31,1540, Serial No. 348,823

10 Claims. (Cl. 260398.5)

The present invention relates to the stabilizaquinone. Other useful diand tri-hydroxy com- 1 tion of glyceride oils and particularly to the pounds, the hydroxy groups of which may have stabilization against oxidative deterioration of been etherized, include guaiacol, gum gualac,

those glyceride oils which contain a large prophloroglucinol, resorcinol, pyrogallol, pyrocateportion of unsaturated glycerides. 5 ch01, tri-butylcatechol, vanillin, thymol, and Sim-l It has been found that these oils are particuilar compounds.

larly oxidizable and that this deterioration is Still other less preferable useful compounds increased wherever the oils are subjected to high are -included in the general group having the temperature deodorization during therefining formula rocess.

It has now been found that when such glyceride oils are heated to relatively high tempera- (z),.(u) tures with combinations of water soluble carbohydrates and particularly sugars such as dextrose and sucrose on the one hand together with an where a: is at least one OH and preferably inaromatic compound, preferably at least cludes two OH groups or even alkoxy-groups and Stituted With amino y y groups O h may less preferably include NHz or COOH or other hand, instead of losing stability and be- CHO or CO or alkyl chains including the same;

Coming more je to eterioration, the oils where n is at least 2; and where y is hydrogen, will become very stable and highly resistant to aryl, alkoxyl, aralkyl, alpharyl, amino, sulpho,

oxidative deterioration and rancidity. aldo, keto or alkyl chains or groups including The sugars and the aromatic compounds are the same. used preferably in equal proportions. They may As examples of the less preferred compounds also be employed in relative proportions varying included in the classification given above are difrom about 1 part of the former and 10 parts of phenylamine, alphanaphthylamine, phenylbetathe latter to 10 parts of the former and 1 part naphthylamine, eugenol, gallic acid and galloof the latter, and the combinations are dispersed tannin. in the glyceride oil which is then heated or they Among the other compounds which may also may be added to the oil during high heat treatbe utilized are ethyl, propyl, butyl, amyl, hexyl, ment to develop marked antioxygenic effectiveor octyl phenols, anilines, naphthols, hydroquiness. nones, pyrogallols or the methoxy, ethoxy, bu-

These sugars and aromatic compounds may be toxy ethers, di-hydroxy or di-amino or hydroxy added separately to the oil to be stabilized or amino naphthalenes, which alkyl groups may or may first be mixed in combination and then may not be substituted by aryl groups such as added to the oil but in either case they are thorphenyl or toluyl such as ethyl, butyl, amyl, hexyl, oughly dispersed in the oil and held dispersed or octyl. Less preferably it is possible to utilize in the oil while the oil is at an elevated temperaaryl substituted phenols, anilines, naphthols, ture in excess of 250 F. and preferably at over naphthylamines, hydroquinones, aminophenols,

400 F. cresols or xylenols.

The preferred aromatic compounds which are Among the other compounds that may be specombined with the sugars have desirably a polycifically employed are polyhydroxybenzenes in substituted benzene ring excluding such com-' which one of the hydroxy groups may be etheripounds as phenol or aniline. These compounds fied such as hydroxyhydroquinone, 1:2:4 triare the dihydroxy benzenes, the di-amino benhydroxy benzene, 1:2-di-methyl-8:6-di-hydroxy zones, the aminohydroxy benzenes and less prefbenzene, 1:2-di-methyl-4:5-tii-hydroxy benzene, erably similar compounds in which the other 1:3-di-ethyl-2:5-di-hydroxy benzene, ethyl pysubstituents in addition to the amino or hydroxy rogallol, methoxy hydroquinone, pyrogallol-lgroup are the alkyl or aryl group such as aryl methyl ether, ethoxy catechol; or naphthols such phenol or an alkyl aniline or even a second as 1:2-di-hydroxy naphthalene, lz-di-hydroxy nuclear chain such as, for example, as in the naphthalene; or poly aminobenzenes or aminocase of an alpha or beta naphthol or an alpha phenols or aminonaphthols such as dior triamor -beta naphthylamine or aminonaphthols, or ino benzenes, 1:5 dihydroxy naphthalene, para diamino or dihydroxy naphthalenes. phenylene cli-amine, ortho-aminophenol, para- The preferred aromatic hydroxy compound to aminophenol, dimethyl para-aminophenol, diuse in accordance with this invention is hydro- B5 butyl aminophenol, di-ethyl aminocresol, phenylhydroxy toluene, benzyl-p-aminoph'enoL. dibenzyl-p-amino phenol, 2:4 diami no dlphenylamine,

p,p-diamino-diphenyl amine, phenyl alpha naphthylamine, alkyl alpha naphthylamine; or less preferably other substituted benzenes such as carvacrol, tribromo or trichlorophenols, etc., or other compounds such as furfural or p-hydroxy phenyl 'morpholine.

The preferred combination of sugar and aromatic compound is a mixture of dextrose and hydroquinone, preferably in equal proportions by weight.

The sugars that are utilized in accordance with the present invention include particularly the monosaccharides such as dextrose and less preferably the di, tri or polysaccharides such as sucrose, maltose, lactose and still less preferably dextrin or solubilized and/or gelatinized starch.

Other sugars that may be utilized for combination with the hydroxybenzenes include raw or refined cane or beet sugar, cane or beet sugar molasses, invert sugar or molasses, corn sugar molasses, carbohydrate alcohols, etc.

The combination is added in an amount of less than 5% and desirably less than 1%. As little as 0.005% to 0.1% will give highly desirable stabilizing results when the glyceride oils are treated in accordance with this invention.

After dispersing the combination of sugar and aromatic compound, such as the combination of dextrose and hydroquinone in the oil, the oil is heated to an elevated temperature, desirably in excess of 250 F. and preferably to between 325 F. and 450 F. for at least 15 to 30 seconds.

It has been found that merely melting a glyceride fat or oil, particularly where the glyceride is solid at room temperature, is not suflicient to give the desired effect and it is necessary to utilize an elevated temperature substantially above the melting point of the glyceride if it normally be solid at room temperature.

During the heating period, the sugar residue may become burnt or charred and, where desired, the burnt residue may be removed as by filtration or centrifuging from the body of the oil, as the stabilization of the oil will already have been effected.

This charring apparently enhances the action of the combination on the oil and it has been found particularly desirable for the heating to be sufliciently high so as to produce charring in order to obtain the fully desirable results of the present invention.

The oil which has been heated with the combination will normally be darker as the result of the elevated temperature treatment and the stabilization will have been effected even though the charred residue be removed from the oil as by filtration or centrifuging. It, however, has been found that the original light color of the oil may be restored by a bleaching process as, for example, with fullers earth or other decolorizing materials and still retaining a substantial enhancement in the stability of the oil.

The results of the present invention are particularly surprising since antioxidants are recognized as losing at least a portion of, and in most cases a major portion of their effectiveness when heated to elevated temperatures such as to 400 F. or more.

Examples I Bleached refined lard was treated by adding thereto and mixing therein combinati ns of sugars andiaromaticcompounds. T he'lard containing the combination was then heated to 400 Rim 5 minutes ,'allowed to cool, and filtered to remove the charred sugar solids. The lard was thereupon tested by bubbling air through a 20 cc. sample of the lard at 125 F. until rancidly as determined organoleptically and by peroxidevalues was observed. The following results were obtained.

I Each of the above materials used with dextrose, when heated in the lard without dextrose results generally in a decrease in stability of the lard.

It is not possible to merely heat the various combinations such as the sugar-hydroquinone combination alone and then add such heated combination to an oil as other antioxidants may be added without further heating and obtain the enhanced stability effect. In order to obtain the interaction it is necessary for the heating to be conducted after dispersal of the combinations in the oil.

The glyceride may, where desired, be bleached or otherwise refined after treatment at the elevated temperaturewith the combination and a distinct enhancement of the antioxygenic effect will be obtained, such enhancement being far in excess of normal expectation.

It is not desirable for the heating to be conducted in a small body of the oil and that oil used as a base for addition to a large body of oil. The most desirable method is for the combinationto be dispersed in the entire body of Lard containing 0.005% hydroquinone and material to be stabilized, followed by subjecting the oil to a high heat in order to produce the desired interaction or result.

Examples II Hydroquinone and sugar were used in lard and tested as above Rancid after hours Lard containing 0.005% hydroquinone alone without heating Lard containing 0.005% hydroquinone and 0.005% dextrose without heating 0.005% dextrose which. hydroquinone-dextrose mixture had first been heated without presence of the lard to 400 F., cooled, and then added to the lard with no further heating Lard containing 0.005% hydroquinone and 0.005% dextrose which hydroquinone-dextrose mixture had first been heated with 20% of the lard to 400 F., cooled and then added to the remainder of the lardwithout further heating Lard containing 0.005% hydroquinone and 0.005% dextrose heated in the lard to 400 F., cooled, and tested '73 Apparently a chemical reaction occurs between the components of the combination and the oil at the elevated temperature whereby the stabilization is effected. as this reaction does not appear to be related to ordinary, negative oxidation catalysis by means of which antioxidants normally exercise activity.

The higher the temperature to which the oil containing the combination of, for example, hydroquinone and dextrose is subjected, the greater the stabilizing action although the sharpest increase in stabilization is between about 325 F. and 450 F.

The heat treatment need not be prolonged, the enhanced antioxygenic effect being obtained in relatively short periods particularly where the higher temperatures are employed. Normally, the oil containing the combination may merely be heated to' the desired temperature and allowed to cool, being held at the high temperature for a period of minutes or more,

The heat treatment will usually be carried out at atmospheric pressure but the use of super or sub-atmospheric pressures may also be employed with satisfactory results.

This process maybe utilized in the treatment and stabilization of a wide variety of refined or crude glyceride oils such as the vegetable oils and fats including cottonseed oil, corn oil, peanut oil, linseed oil, soya bean oil, olive oil, etc., the animal oils and fats including lard, tallow, oleo oil, cod liver oil, halibut liver oil, mackerel oil, menhaden oil, herring oil, shark liver oil, butter, etc.. the glyceride soap oils and the sulfonated oils.

Not only is the oil stabilized, but componen of the oils are also stabilized. For example, the vitamin A content of fish liver and other oils, the carotene content of butter fat and similar substances associated with the oils which may be destroyed or reduced by oxidation are highly stabilized by this treatment.

This invention is, however, particularly beneficial in the treatment of those glycerldes which as 4 to 6 hours and the objectionable flavors and odors originally present in the oil may be removed therefrom While the combination is exerting its enhanced antioxygenic effect.

It has been found particularly desirable for a small amount of the combination to be added to high fat containing animal products, heating at atmospheric orelevated pressures to temperatures of about 250 F. so that the glyceride oil or fat contained therein is released from the meat or fish animal product and a highly stabilized animal glyceride is obtained.

For example, to a kettle of hog fatcontaining 70% total glycerldes may beadded 0.02% of a combination of gum guaiac and dextrose against the weight of the hog fat and the combination placed in a steam kettle with steam being injected into the kettle to produce about 45 pounds pressure. After a 4 to 6 hour treatment, the pressure may be released and the rendered lard removed. The stability of the lard obtained in this manner will be much greater than if the combination had merely been added to the lard after rendering.

For example, when a small amount of a combination of gum guaiac and dextrose is added to hog fat and the hog fat containing the combination is then rendered at a temperature of 275 F. for 4 hours, the rendered lard removed from the rendering kettle has a far greater stability than where a proportionate amount of the com-' where the rendering is conducted at over 250 F.

contain large proportions of unsaturated fatty acids, as the combination appears to react more completely with these unsaturated oils at the elevated temperatures.

The sugar, preferably dextrose, is utilized desirably in crystalline and anhydrous form in order to obtain the most enhanced antioxygenic effect.

Although the aromatic compounds and preferably the di-substituted benzene may already have some antioxygenic effect when added to the glyceride oils and without the heat treatment, nevertheless such antioxidant power is very greatly increased and enhanced by heating the combination in the oil to over 250 F. and preferably to 325 F. to 450 F. 4

The stability of the treated oils will often be enhanced from 50% to' 500% or more by the heat treatment in the presence of these combinations as compared to the stability which would be obtained by the addition of the combinations without the heat treatment described in this invention.

The most important features of the present invention reside in the fact that the added materials are not normally present in the oil to be stabilized and upon addition are thoroughly dispersed in such oil. The heat treatment is carried out for a sufiicient length of time to increase the stability by usually not less than 50% over the stability of the unheated oil.

While the combination is dispersed in the oil at the elevated temperature of, say 400 F., superheated steam may, where desired, be continuously injected into the oil over a period as long resulting in a most highly stabilized oil.

In a similar manner, a small amount of the combination may be added to the rendering kettle in the rendering of other meat and fish oils and fats including tallow, menhaden oil, herring oil, etc., or to the cooking kettles in the manufacture of fish meals, particularly high glyceride containing fish meals, and where the temperature is at least about 250 F., the desired interaction will result producing enhanced stabilization.

Where the glyceride oils are heated over long periods to temperatures over 250 F. and desirably to temperatures over 300 F., small amounts of the combination may be added to the oils at regular intervals of 5 to 20 hours followed by filtration to remove the insoluble portion before adding a fresh amount of the combination. In this manner, the glycerldes will be held in highly stabilized and non-rancid condition over very long periods.

bricating oils followed by temperature treat-,

ments of over 250 F. and preferably between 350 F. and 500 F.

In carrying out the above described high temperature treatment, it is important that the solids of the combinations be uniformly dispersed or distributed throughout the body of the oil in subcase the fully desirable results of the present invention are not obtained.

It is desirable that the oil after treatment in accordance'with the present invention will not be materially changed in its odor or fiavor. The oil will, however, have a darker color which may be removed by subjecting it to a bleaching operation.

It hasalso been found that desirable results are obtained where the combinations are mixed with the oil or fibrous materials containing the glyceride oil and then the oil is heated to a tem-' perature of, say from 250 F. to 500F. under a reduced pressure, such as under a gas pressure less than 1 pound per square inch, to cause distillation of part or all of the glyceridefoil composition and it has been observed that such distilled fraction is highly stable and is also free of I the combination which has served as the stabilizing ,agent at the elevated temperature of distillation.

After treatment of the glyceride oil with the combination at the elevated temperature, the unsaponifiable fraction may be removed as by alcoholic extraction and said unsaponifiable fraction utilized for addition to other oxidizable oils to protect them against oxidative deterioration. .Combinations of sugars and hydroxylamine may also be employed for addition to the oils followed by the heat treatment to over 250 F. The present application is a. continuation in part of application Serial No. 247,631 filed December 24, 1938, and through said application was copending with application Serial No. 249,166 filed January 3, 1939, now Patent No. 2,198,210; application Serial N0. 292,613 filed August 30, 1939, now Patent No. 2,198,208; application Serial No. 260,898 filed March 10, 1939, now Patent No. 2,198,211; and application Serial No. 304,945, filedNov ember 1'7, 1939, now Patent No. 2,216,711. The present application is particularly directed to the use of a poly hydroxy aromatic compound and a water soluble carbohydrate, particularly hydroquinone and sugar, in the treatment of glycerideoils when accompanied by a heat treatment to stabilize such oils against oxidative deterioration.v Having described my invention, what I claim is:

1. A process of stabilizing oils subject to oxidative deterioration, whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a water soluble carbohydrate and a roup consisting of hydrogen, aryl, alkoxyl, aralkyl, alpharyl, amino, sulpho, aldo, keto and alkyl chains including the' same, and heating to" in excess of 250 F.

2. A process of stabilizing oils subject to oxidative deterioration whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small a polyhydroxy benzene, and heating to in excess of 250 F.

4. A process of stabilizing glyceride oils subject to oxidative deterioration whereby they become less subject to such -deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a sugar and hydroquinone, and heating to in excess of 250 5. Alprocess'of stabilizing oils subject to oxidative deterioration, whereby they become less subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a combination of a water soluble carsmall amount of a compound having the general formula least 2 and where y is a radical selected from the in the oil, said aromatic compound where a: is a radical selected from the group consisting of 0H, alkoxy, NI-Iz, COOH CHO, CO and alkyl chains including the same, where n is at least 2 and where 11 is a radical selected from the group consisting of hydrogen, aryl, alkoxyl, aralkyl, alpharyl, amino, sulpho, aldo, keto and alkyl chains including the same, said reaction product having been formed by heating the combination in the oil to a temperature in excess oi. 250 F. whereby an'enhanced antioxygenic effect is obtained.

8. A glyceride oil having a high proportion of unsaturated glycerides, said oil being normally subject to oxidative deterioration, said oil carryme the reaction product of a combination ofa sugar and a polyhydroxy benzene, said reaction product having been formed by heating the combination in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

9. A glyceride oil normally subject to oxidative deterioration carrying the reaction product of a combination of a water soluble carbohydrate and an aminohydroxy benzene, said reaction product in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

10. A process of stabilizing glyceride oils subject to oxidative deterioration, whereby they become less, subject to such deterioration, which comprises adding thereto and dispersing therein a small amount of a water soluble carbohydrate and a small amount of a compound having the where a: is a radical selected from the group consisting of OH, alkoxy, NH2, COOH, CHO, C0

and alkyl chains including the same, where n is at least 2 and where y is a radical selected from the group consisting of hydrogen, aryl, alkoxyl, aralkyl, alpharyl, amino, sulpho, aldo, keto and alkyl chains including the same, heating to in excess of 250 F., and then removing the unsaponifiable fraction therefrom.

' SIDNEY MUSHER.