US2121545A - Art of refining edible oils, fats and analogous products - Google Patents

Description

Patented June 21 1938 UNi-TED stares parent t:

ART OF REFINING EDIBLE OILS, FATS AND ANALOGOUS PRODUCTS No Drawing. Application June 20, 1935, Serial 16 Claims. Our present invention is concerned with'improvements in refined edible oils, fats and generally analogous materials such as Waxes and rosins and with improved processes by which such products are produced.

An object of the invention is to provide improved edible products typical examples of which are refined corn oil, cotton seed oil, linseed oil, castor oil, tallow, lard, cocoanut oil, etc., so refined and purified that their spoilage or rancidity due to bacterial or mould attack'is positively inhibited over much longer periods of time than has heretofore been considered possible. In factthe refined products will apparently keep indefinitely. I

Another object is to provide a greatly simpli+ fied and cheapened and more expeditious process of refining such materials.

Another object is to provide a highly emcient .0 process by which the loss in the refining operation of valuable oil or other desirable end products is greatly reduced in comparison with prior processes.

Another object is to provide a process in which :5 the foots constitute a valuable by-product convertible into active refining agents for re-use in refining subsequent batches of.the same material from which the foots were derived.

Heretofore refining processes for materials of v the types here involved have concerned them selves with one or more of the following distinct refining steps: (1) removal of free acids, (2) bleaching, (3) removal of mucilaglnous and other deleterious materials, and (4) rendering the final product tasteless and odorless.

The practice of bleaching has been carried out more to satisfy a popular misconception as to the 1 impurity of colored oils than because of any sound reasons which can be advanced for increased nutritional, therapeutic or other valuable properties of the bleached product.

In fact' modern bleaching processes involving violent chemical reactions such as pyrogenic decomposition not only result in a substantial loss of refined end product but seriously impair or destroy the vitamin content thereof. waste of end products and increase in worthless foots have resulted from prior acid removal methods and prior methods of separating out .50. the mucilaginous constituents of crude oils.

It has previously been proposed to use organic peroxides as bleaching agents but as evidenced by the Ludecke Patent No. 901,718 and by the patent to Kokatnut et al., No. 1,883,707, such per- '55 oxides have always been reacted with the oils at Y Similar Renewed November 22, 1937 temperatures in excess of 109 C. at which temperatures pyrogenic decomposition occurs and considerable conversion of otherwise valuable oil into worthless fonts results. Such .prior processes have likewise involved the use of alkali earths both as pyro-oxygen decomposition agents and to neutralize the free fatty acids present. Such alkalis have heretofore been used in excess of the amount required to efi'ect such neutralization. An objection to the use of this type of alkali is that the alkali earth soaps resulting from the reaction are soluble in the oils and are diflicult to eliminate from the end product.

The patent to Kokatnur above identified suggests that the processwhich it discloses helps to inhibit rancidity and tends to render the oil tasteless and odorless. However that patent teaches no reliable method of accomplishing such results and their sporadic and partial accomplishment by the patented process was entirely accidental and fortuitous and could not be duplicated because the critical factors determinative of such results were not known or even surmised.

We have discovered that there are two controlling factors involved in producing these results, one is the use of peroxides in excess of that required for decolorizing and in suificient quantity so that the final product still contains a substantial amount of peroxide. We have likewise discovered that by carrying out the process at temperatures in the order of to 0., that is at temperatures below the temperatures of pyrogenic decomposition of the peroxides, bleaching may be substantially inhibited although some decolorization does occur. The chemical reaction which takes place'is mild as compared to prior processes involving the. use of organic peroxides. The amount of end product is increased and from the fonts of the process we are able to produce organic peroxides from natural constituents of theoil which are suitable for treating subsequent batches of the oil.

We have found that deodorizatlon and rancidity can be inhibited indefinitely'if 'sufiicient peroxide is used so that the end product still carries peroxide. This is in direct contra-distinction to prior methods involving temperatures high enough to efiec't pyrogenic decomposition of the peroxides and while the following explanation is merely tentative, experiments would seem. to bear it out. Whereas heretoforefpractically all of the peroxide has been decomposed and spent in the violent chemical reaction which causes bleaching, the peroxide has little effect on the other phases otrefining. Where however as rious ingredients from the crude'oil, although whether this is due entirely to the use of an excess of peroxide and the lower temperature,'or due to the different type and amount of alkali. used, or due in part toall of these factors is difilcult to determine.

In our present process we preferably use alkali metal hydroxides, carbonates or weak acid salts as opposed to, alkali earth hydroxides such as those of calcium, barium, strontium and magnesium. This improvement in the process prevents the formation of alkali earth soaps which are soluble in oils and contaminate the final oil product and causes the formation of' soaps in-.

soluble in oil. As a result the soap produced from the free fatty acids by our process, settles out along with mucilaginous and deleterious matter thrown out of the solution or emulsion by the organic peroxides. The fact that the foots in our process carry substantially all of the mucilaginous matter and smaller amounts of the neutral 011 than they have carried heretofore, indicates that the emulsifying property of gums, rosins and soap has been broken down or reduced by the peroidde.

Where in accordance with the preferred embodiment of the invention we use a peroxide of on or more of the natural ingredients of the crude oil, such peroxides can'be derived from the foots. In corn oil refining for instance we use the peroxides of the total corn oil fatty acids and the foots from such refining process are essentially composed of such fatty acids. Such corn oil peroxides can be made from the foots at a cost approximating 25 to 50 cents per pound as opposed to the commercially available benzoyl v peroxide which costs approximately 4 to 8 times as much. Similarly, peroxides of cotton seed oil, cocoanut oil, linseed oil etc. prepared from .the roots may be used to refine the respective oils.

The fact that in our process peroxides act as anti-oxidents rather than as pro-oxidents and inhibit rather than promote rancidity, is directly contrary to the teachings of the prior art. That the action of the peroxides continues long after the heat treatment has occurred is evidenced bythe fact that deodorization in many cases requires several weeks and occurs in storage. Such deodorization of course may be effected more rapidly if desired by blowing superheated steam through the oil while the latter is under vacuum.

Even when this is resorted to however, oils which normally take'ten to twelve hours of steam blow-' ingxcan be completely deodorized in approximately V to V ofthat time.

The invention may be more fully understood from the following typical examples of methods for treating certain oils, fats and waxes.

Example I-,-C0 m oil refining A thousand parts of crude corn oil containing acids are treated with it tends The refined neutral oil so It would merely bring tion and peroxides maybe introduced into the crude oil together, in which event careful control particularly the oil be bleached too much. A minoramount of bleaching always takes place in neutraliza- -tion whether the peroxide is present or not.

While the presence of alkali enhances bleaching, to make other phases. of the refining process more ineffieient. Therefore, if the alkali is added at the beginning of the process the neutral oil should be separated from the foots as soon as the desired color is obtained. The facts are distinctly superior to those obtained from prior processes being of better color consistency and odor and containing less neutral oil. obtained is between 95 and 96% of the crude in contradistinction to prior methods where not more than 92 to 93% of refined oil is obtained'from the crude.

Variations of Esamp l e I While the above example deals with a preferred procedure, it will be apparent to those skilled in the art that many variations thereof might be made without departing from the spirit of the invention. For instance instead of using caustic soda, other alkali metalhydroxides may be used. Sodium carbonate, borate orphosphate, with or without the addition of bicarbonate, boric acid, or phosphoric acid to reduce their pH may be used to neutralize the free acid or bring down and precipitate the mucilaginous matter or both.

Neutral solids such as aluminum sulphate or common absorbents such as fullers earth, and certain acids like sulphuric, nitric and phosphoric in high dilutions may also be used to precipitate the mucilaginous matter. Of course this treatment will not neutralize the free acids, if present. down the mucilaginous matter in the presence of organic peroxide. From the standpoint of refining, however, this is more important than neutralization and must be done thoroughly. Particularly good results are obtained in cocoanut oil, cotton seed oil, olive oil and soy bean oil by this process. However almost any oils, fats and waxes may be refined by this process with advantage. Most oils and fats contain in their crude unrefined state 1 to 10% of free acids. Palm oil and many waxes contain free acids in a much higher percentage namely as high as 50 to 60% and in such cases neutralization should not be resorted to at all in refining. The materials which contain such high percentages of free acids should be treated with neutral salts or acids as precipitant for foreign materials, since neutralization processes would result in the loss of too much product. In the treatment of waxes, free acids are part and parcel of the'wax and there would be no good purpose served in throwing the free acids away. .The ofl refined by our process is in most instances characterized by a lower viscosity than similar oil refined by Prior methods. This for many purposes is helpful due to the more ready flowability of the oil. Lower of temperature is essential less the prolonged induction period for oxidation which characterizes oil refined by our process.

Example IIPreserving lard prevent rancidity. In cases where the material.

is colored as in the case of cows butter and where it is undesirable to bleach it, a lower limit of peroxide should be used. A negligible amount of free acid would help to slow up the bleaching action. The product so produced is insured against rancidity for long periods of time and tests indicate that biscuits or other bakery products made with such preserved oils or fats also seem to show a far longer life'than products made with ordinary oil or fats.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process of refining oils, fats or waxes, which includes the steps of reacting material to be treated with organic peroxide at a temperature substantially less than 100 C. and in the presence of a precipitant for mucilaginous material said material and said precipitant being of the type for which the peroxide acts as a catalyst in facilitating precipitation.

2. A process of refining raw non-mineral oils, which includes the steps of reacting oil with organic peroxide at a temperature well below the pyrogenic decomposition temperature of said peroxide and in the presence of a precipitant which neutralizes free acids without producing, soaps soluble in the material being treated.

3. A process of refining oils. fats or waxes, which includes the steps of reacting material to be treated with organic peroxide derived from the foots of the refining process at a temperature well.

cient amount of peroxide being introduced into the material being treated to insure the presence of peroxide in the end product.

5. A process of refining oils. fats or waxes, which includes the steps of reacting material to be treated with organic peroxide at a temperature well below the pyrogenic decomposition temperature of said peroxide and in the presence of a precipitant for mucilagin'ous material which neutralizes free acids without producing soaps soluble in the material being treated, a. sufiicient amount of peroxide being introduced into the material being treated to insure the presence of peroxide in the end product. 1

6. A process of refining oils, fats or waxes, which includes the steps of reacting material to be treated with organic peroxide at a temperature well below the pyro genic decomposition tempera- V ture of said peroxide and in the presenceof a precipitant for mucilaginous material which neutralizes free acids without producing soaps soluble in material being treated and separating the facts from the desired end product, a sufiicient amount of peroxide being introduce'd into the material being treated to insure the presence of peroxide in the end product. 1

7. A process of refining edible oils and fats which includes the steps of reacting material to be treated with organic peroxide at a temperature in the order of 50 to 60 C. and in the presence of a precipitant for mucilaginous material.

8. A process of refining edible oils and fats which includes the steps of reacting material to be treated with organic peroxide at a temperature in the order of 50 to 60 C. and in the presence of an alkaline precipitant for mucilaginous material, which precipitant is of the type capable of neutralizing free acids without the production of soaps soluble in the desired end product.

9. A process of refining edible oils and fats which includes the steps of reacting material to be treated with organicperoxide derived from the roots or the refining process and at a temperature in the order of 50 to 60 C. and in the presence of a precipitant for mucilaginour material of the type capable of neutralizing free acids without the production of soaps soluble in the desired end product and separating the foots from the end product.

10. A process of refining corn oil, said refining process including reacting peroxide with the oil at a temperature well below pyrogenic decomposition temperature of the peroxide, said' process also including the introduction of an agent'serving as a precipitant for mucilaginous material and a neutralizer of free acids.

11. A process as set forth in claim 9 wherein the peroxides are formed. from the foots separated out during the refining process.

12. A method as set forth in claim 10 wherein peroxides-of corn oil fatty acids are used.

13. A method of refining vegetable oils which includes the steps of adding an organic peroxide with crude oil and reacting the peroxide with the oil in non-violent fashion and at a temperature below the pyrogenic decomposition temperature of the peroxide whereby to effect partial bleaching and'adding to the material being treated, ,an, alkali for neutralizing free acids without the formation of oil-soluble soaps.

14. A process of refining edible oils or fats which includes simultaneously reacting the material to be treated with organic peroxide at a temperature in' the order of 50 to C. and neutralizing free acids with an alkali metal hydrox-