US2282806A - Treatment of oils - Google Patents

Description

Patented May 12, 19 42 Sidney Musher,

New York, N. Y., assignor to Musher Foundation Incorporated, New York,

N. Y., a corporation of New York No Drawing. Application July 31, 1940, Serial No. 348,825

9 Claims. (Cl. 260-3985) The present invention relates to the stabilization of glyceride oils and particularly to the stabilization against oxidative deterioration of those glyceride oils which contain a large proportion of unsaturated glycerides.

It has been found that these oils are particularly oxidizable and that this deterioration is increased wherever the oils are subjected to high temperature deodorization during the refining process.

It has now been found that when such glyceride oils are heated to relatively'high temperatures with finely divided, preferably deoiled, soya bean flour, sesame flour, peanut fiour, cottonseed fiour, or the flours ofother seeds and nuts, originally containing at least about to of glyceride oil against the solids content of the seeds and preferably from which some or a major part of the oil has been removed, instead of losing stability and becoming more subject to deterioration,

which some or a major part of the oil has been I removed.

The finely divided seed or nut flours, which are preferably in substantially oil exhausted form, and which flours are referred to herein asthe seed flours, are dispersed in the glyceride Oil which is then .heated or they may be added tr the oil during high heat treatment to develop marked antioxygenic effectiveness.

For example, the oil may have been removed from the soya beans, sesame seeds, peanuts, cottonseed or corn germ by expeller expression, hy-, draulic expression or by solvent extraction and the residue thus obtained, preferably finely divided to about 50 mesh and desirably to over 100 mesh, may be added to the, oil and heated therein.

The seed flour is added in an amount of less than 10% and desirably less than 5%. As little as 0.05% to 0.5% will give highly desirable stabilizing results when the glyceride oils are treated in accordance with this invention.

After dispersing the seed fiours 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 sufflcient to give the desired effect in and it is necessary to utilize an elevated temperature substantially above the melting point of the glycerideif it normally be solid at room temperature.

During the heating period, the flour may become burnt or'charred and, where desired. the f burnt residue may be removed as by filtration or centrifuging from the body of the oil, as the l.

stabilization of the oil will already have 'been This charring apparently enhances the action of the four on the oil and it has'been found par-. ticularly desirable for the heating to be suificiently 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 flour will be darker as the result of the elevated temperature treatment and the stabilization will have been eflfected 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. I v

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.

I Example I press cake was added but without being subjected to the 400 F. heat treatment was similarly tested along with a sample of the original untreated lard, with the, following results:

. r Rancid after Untreated lard 2 hours Lard containing 1% soya flour press cake unheated Lard containing 1% soya flour press cake heated to 400 F. for 1 minute, cooled and filtered 13 hours The glyceride may, where desired, be bleached or otherwise refined after treatment at the ele- 4 hours vated temperature with the seed flour 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 flour to be dispersed in the entire body of material to be stabilized. followed by subjecting the oil to a high heat in order to produce the desired interaction or result.

Apparently a chemical reaction occurs with 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 soya flour is subjected, the greater the stabilizing action although the sharpest increase in stabilization is between about 300 F. and 400 F.

Example If Bleached refined lard was prepared in the following manners:

The lards were then tested for stability as in.

Example I with the following results:

Rancid after- Lard A 3hours Lard B 4 hours Lard C 1 /2 hours Lard D 13 hours Lard E 21 hours 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 011 containing the seed flour may merely be heated tothe 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 may be 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 011, corn oil, peanut oil, linseed oil, soya bean oil, olive oil, etc, the animal oils and fats includinglard, 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 sulionated oils.

This invention is, however, particularly bene- :icial in the treatment of those glycerides which contain large proportions of unsaturated fatty acids, as the seed flours appear to react more completely with these unsaturated-oils at the elevated temperatures.

The seedssho'uld be finely ground or crushed as, for example, placed in flour form. They may.

' pei-atures.

invention reside in the fact that the also be madeinto paste form by grinding with -from 50% to or an oil or by placing the combination through a colloid mill so as to disintegrate the cell structures and release the antioxygenic effect more readily at the higher teml'he seed flours are usually'charred in the oxidizable materials such as lard or fish oils, whereby the necessary interaction is obtained.

Although the seed flours may already have some antioxygenic effect when added to the glyceride oils and without the heat treatment, nevertheless such antioxidant power is limited and is much less than the stabilizing effect obtained after the addition of the flours and dispersion in the oil to be stabilized, followed by the heat treatment to over 250 F. and preferably to 325 F. to 450 F.

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 substances as compared to the stability which would be obtained by the addition of the flours without 'the heat treatment described in this invention.

The most important features of the present added material is not normally present in the oil or oxidizable material to be stabilized and upon addition is 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.

As a preferred method for the heating, the entire body of oil containing the seed flours thoroughly dispersed therein may be raised to the desired temperature with agitation, maintaining a uniform temperature throughout, and then permitted to remain at this temperature while agitating. The oil may then be allowed to 0001 without refrigeration.

While the flour is dispersed in the oil at the elevated temperature of about 400 F., superheated steam may, where desired, be continuously injected into the oil over a period as long as, 4 to 6 hours and the objectionable flavors and odors originally present in the oil may be removed therefrom while the flour is exerting its enhanced antioxygenic effect.

It has been found particularly desirable for a small amount of seed flour to be added to high fat containing animal products, heating at atmospheric or elevated 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 ani mal glyceride is obtained.

For example, to a kettle of hog fat containing 70% total glycerides may be added 0.5% of soya flour press cake 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 soya press cake had merely been added to the lard after rendering.

For example, when a small amount of a seed flour is added to hog fat and the hog fat containing the flour is then rendered at a temperature of, for example, 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 seed flour is added to the lard after rendering and the improvement in stability is even greater than where the seed fiour is added to the lard after rendering and the lard containing the flour is then heated to 275 F. for 4 hours.

Apparently a further interaction takes place by adding the flour to the rendering kettle where the rendering is conducted at over 250 F. resulting in a most highly stabilized oil.

In a similar manner, a small amount of seed flour may be added to the rendering kettle in the rendering of other meat and fishoils 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 seed flours maybe added-to the oils at regular intervals of 5 to hours followed by filtration to remove the insoluble portion before adding a fresh amount of the seed flour's. In this manner, the glycerides will be held in highly stabilized and non-rancid condition over very long periods.

One of the highly unsaturated glyceride oils that has been found particularly desirable for treatment in accordance with the present invention is the crude unrefined corn oil obtained from the hydraulic or expeller expression of dry milled corn germ' and where neither the corn nor the corn germ has been subjected to steeping in sulphurous acid water prior to removal of the germ.

There may be added to the crude corn oil a small proportion of the seed flour followed by elevated temperature treatment of at least about 250 F. and a highly stabilized glyceride oil product will be obtained.

It has been found most-important to use the corn oil as expressed from the dry milled germ and which corn oil has not been subjected to any of the usual refining processes.

Together with or in lieu of the seed flours, there may also be employed their extracts'and particularly those extracts obtained by the use of an alcohol soluble solvent. The extracts are desirably chosen from a solvent having the formula XOH where X is hydrogen or a low molecular weight aliphatic group. There may be particularly utilized water, methyl alcohol, ethyl alcohol, propyl alcohol or butyl alcohol.

The extracts may be prepared by immersing the finely divided flours in the solvent such as in methyl alcohol, using about from 5 to 15 parts of alcohol to .each part of flour, agitating for from 5 minutes to 1 hour at a slightly elevated temperature, filtering out or otherwise removing the alcohol containing the dissolved extracted material, and then removing the alcohol, preferably under reduced pressure, whereby the extracted material remains substantially free of the solvent.

These extracts may be applied in the manner analogous to that described above for the seed flours themselves and will show an enhanced antioxygenic activity when added to oils followed by treating said oils at a temperature of at least 250 F. or more.

In addition to treating the glyceride oils and fats with the seed flours, the essential oils and particularly the oxidizable unsaturated essential vated temperature treatment to enhance the antioxygenic effect.

.The seed flours also exert an enhanced antioxygenic effect when added in small proportions to the substantially non-volatile, high molecular weight, hydrocarbon oils and particularly the lubricating oils followed by temperature treatments 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 seeds be uniformly dispersed or distributed throughout the body of the oil in substantially fineparticles and that the heating be carried out with substantial exclusion of the atmosphere or without contact with air. I v It is moreover desirable for the seeds to be maintained in dispersed condition during the heat treatment and so that they will not tend to settle or conglomerate or be present in the form of large lumps or particles. since in the latter case 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 flavor. The oil will, however, have a darker color which may be removed by subjecting it to a bleaching operation.

The seeds or seed flours may where desired be subjected to'boiling or treatment with acid such as by boiling soya flour in a 2% acetic acid solution for a period of from 20 minutes to 4 hours, followed by neutralization and drying and then utilized in accordance with the present invention.

The seed flours may also be first treated with saturated or superheated steam under pressure or under vacuum at temperatures substantially above 250 F., particularly in an acid'medium having a pH of less than 6 and preferably less than 4.5. Such flours may then be utilized in accordance with the present invention.

It has also been found that desirable'results are obtained where the finely divided seeds are mixed with the oil or fibrous materials contain- Bythe term seeds, as used hereinfthere are also included such additional materials as the seed germs such as corn germ, wheat germ, and rice germ, preferably in deoiled condition, rice bran, peach kernel, watermelon seed, tomato seed and olives.

Instead of utilizing the seeds when they have fully ripened or matured upon the vine, it is also possible to remove them from the plant when they are still unripened and have a high moisture.

content. They may then be dried to a moisture content of under 20% and preferably under 10% and then converted to a flour with or without deoiling and added to an oil followed by heating as described to enhance the antioxygenic effect.

Although this isparticularly applicable to the field of the oil containing. seeds when removed from the flesh or pods, it is also possible sometimes to dehydrate the entire unripe pods or fruitcontaining the seeds so that it may be powdered with or without deoiling and for addition to oils.

Although these materials have some antioxygenic eflect, the efi'ect is considerably enhanced when Less preferably, there may be also utilized in accordance with the present invention the grasses or stalks of the cereals or forage-legumes and grasses and their extracts in substantially unripe condition.

The present application is a continuation in part of application Serial No. 247,631 filed December 24, 1938 and through said application continues the subject matter of applications, Serial No. 135,169, filed April 5, 1937; Serial No. 294,633, filed Sept. 13, 1939, now Patent 2,198,204; Serial No. 249,166, filed January 3, 1939, now Patent 2,198,210; and Serial No. 260,898, filed March 10, 1939, now Patent 2,198,211. Through application, Serial No. 135,169; filed April 5, 1937, the present application continues the subject matter of application, Serial No. 733,517, filed July 2, 1934, now Patent 2,097,252.

Having described my invention, what I claim is:

1. A processof 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 finely divided seed and heating to in excess of 250 F.

2. 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 finely divided seed and heating to in excess of 250 F. r

3. 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 finely divided seed, heating the oil to a temperature sufiiciently high to char the seed, and then filtering off the residue.

ject to oxidative .deterioration whereby they become less subjectito such deterioration, which comprises adding thereto and dispersing therein a small amount of a finely divided peanuts and heating to a temperature suiiiciently high to char the finely divided peanuts.

6. 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 finely divided soya fiour and heating to in excess of 250 F.

7. An oil normally subject to oxidative deterioration carrying the reaction product of a finely divided seed in the oil, said reaction product having been formed by heating the seed in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

8. A glyceride oil normally subject to oxidative deterioration carrying the reaction product of a finely divided seed in the oil, said reaction product having been formed by heating the seed in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic effect is obtained.

9. A glyceride oil having a high proportion of unsaturated glycerides normally subject to oxidative deterioration, said oil carrying the reaction product of a finely divided seed in the oil, said reaction product having been formed .by

. heating the seed in the oil to a temperature in excess of 250 F. whereby an enhanced antioxygenic efi'ect is obtained.

SIDNEY MUSHER.