Refining method for crude cottonseed oil

Conclusion Acknowledgment is again given to Mr. Nelson W. Humbaugh who carried out the analytical work here recorded. A proposed revision of the refining method as at present written which is intended to embody all the points found desirable, is now in the hands of the members of the Refining Committee for consideration and test.     

Constituents of crude cottonseed oil

Summary A small quantity of so-called vegetable mucilage was separated from crude cottonseed oil. It was precipitated from an aqueous solution by normal lead acetate. No water-soluble gum could be detected. Experiments showed that this mucilage readily emulsifies the oil with water and that the emulsion does not break after standing for several days. It is believed that the mucilage constitutes only a very small part of the non-glyceride substances present in the oil. Treating the oil with water and then extracting the separated oil repeatedly with large volumes of alcohol only removes part of the resin. The resin is partially removed from an alcoholic solution by an alcoholic solution of copper acetate in the form of a dark yellow flocculent precipitate. The copper salt is insoluble in alcohol and ether. It is believed that part of the deep red color of the crude oil is due to this resin. Presented at the 16th Annual Convention of The Am. Oil Chem. Soc’y, New Orleans, May, 1925.     

Constituents of crude cottonseed oil

Summary Crude cottonseed oil contains in addition to the constituents previously reported a lecithin type of phosphatide which gives an ether-soluble compound with cadmium chloride. This phosphatide can only be partially removed from the oil by extraction with alcohol. It has been found in the “settlings” from this oil. The treatment of the oil with water causes only a partial separation of this phosphatide. The phosphatides, resins, and presumably other substances present in small quantities in the crude oil have emulsifying properties and are undoubtedly the cause in part for the retention of oil in the soap stock when the oil is refined by caustic soda.     

Constituents of crude cottonseed oil

Summary The alcohol-soluble portion of the settlings which separate from clear crude cottonseed oil has been studied further. Although the oil had stood in the laboratory for about 3 years before the settlings were removed for the investigation, it was free from rancidity and in excellent condition. Palmitin, amounting to about 25 per cent, and di-palmitin, amounting to about 1 per cent of the total settlings, were isolated and identified. About 0.1 per cent of a phytosteroline, which gave an acetyl derivative melting at 166° to 167° C., was obtained. It appears from the results of this investigation that the dipalmitin, which was probably produced by the hydrolysis of a very small quantity of a tri-glyceride, accounts in part for the acetyl value obtained with cottonseed oil. As no investigation has succeeded in showing the presence of any hydroxy acids in cottonseed, or for that matter in many other oils giving a comparatively small acetyl value, the values noted may be largely due to the presence of small quantities of various di-glycerides.     

Estimation of gossypol in crude cottonseed oil

Summary 1. Pyridine promotes the precipitation of gossypol by aniline from oil solutions. A quantitative method for the estimation of gossypol in crude hot pressed cottonseed oil is outlined, which involves the use of a pyridine-aniline (4:1) reagent. 2. Samples of crude oils from six different mills analyzed from 0.049 to 0.105 per cent gossypol. 3. Gossypol in crude oils is rendered non-precipitable by heating the oil to 150° C. for 30 minutes. Heating at lower temperatures decreases the yield. 4. Photomicrographs are presented which show the crystal form of dianiline gossypol precipitated in the presence of pyridine. This work was carried out under the direction of L. C. Haskell, to whom grateful acknowledgment is made. The writer is indebted to M. C. Kibler for assistance in conducting the analyses.     

Net loss in crude cottonseed oil refining

Reasons are given for failure to arrive at a satisfactory materials balance on the crude oil refining operations, and a simple laboratory method is proposed for evaluating the refinery foots which avoids the necessity of obtaining their amount or analysis.     

Refining cottonseed oil at high rates of shear

Summary Ten crude cottonseed oils obtained from different areas in the South and Southwest were refined with and without the use of high-shear agitation in the step involving the initial mixing of the crude oil and caustic soda solution. In each instance the use of high shear produced a lower color in the refined oil. The improvement with some oils was not marked because they either refined very well by the ordinary method or failed for some unexplained reason to respond readily to high-shear mixing. However a good proportion of the oils which were quite dark after refining by the ordinary method refined to a much lighter oil when high shear was used. It was established that in high shear refining the color of the refined oil decreased as the temperature at which high shear was used decreased, the time at high shear increased, and the rate at which shear was applied increased. However an increase in the latter above a certain value had no effect. Also it was found that the color of the refined oil decreased as the amount and strength of the caustic soda solution increased. Absorption spectra of some of the processed oils indicated that high shear was more effective than ordinary mixing in removing from an oil the gossypol-like and carotenoid color bodies. Presented at the 28th fall meeting of The American Oil Chemists’ Society, Minneapolis, Minn., Oct. 11–13, 1954. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Gossypol content and refining losses on crude cottonseed oil

Summary 1. Gossypol has been found to be almost universally present in hot pressed crude cottonseed oils from all of the important cotton growing sections in the United States. 2. The average amount found in crude oils from 62 scattered mills was 0.05 per cent. The highest percentage found in a hot pressed oil was 0.210. Only 7 out of 124 oils failed to show the presence of gossypol. 3. Since gossypol content was not found to be proportional to deviation from average refining loss, it was concluded that at least a portion of the gossypol occurs in the oil in the bound state, associated with protein fragments.     

Phase relations pertaining to the solvent winterization of cottonseed oil in hexane and in acetone-hexane mixtures

Summary Systematic phase relation data pertaining to the solvent winterization behavior of a refined cottonseed oil have been obtained for two additional solvents; namely, commercial hexane and a mixed solvent consisting of 85% by weight of acetone and 15% of hexane. Graphs have been constructed to show the effect of oil-solvent ratio, chilling temperature, holding-time, and agitation on the percentage of solid removed, the degree of winterization and the settling qualities of the solid separating. These data, with those previously reported for acetone (1), afford a basis for the selection of the optimum conditions and procedures in the application of solvent winterization to cottonseed oil and bring out the relative advantages, disadvantages, and limitations of the three solvents. The acetone-hexane mixture seems to combine the advantages and eliminate the disadvantages of either of these solvents alone. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Continuous refining of crude cottonseed miscella

A simple, easily controlled process for continuous caustic refining of crude cottonseed miscella in a two-stage system is described. The effect of crude oil quality, oil: hexane ratios, temp, mixing conditions and chemical treatment are noted. The chemical reactions in the process are followed microscopically. The process yields a refined oil of less than: 1.0 bleach oil color, 0.03% free fatty acid and 15 ppm soap, and with 30~40% oil savings over Official Cup Loss. The by-product soap may be used advantageously in the meal from the extractor unit. Presented at the AOCS Meeting in Minneapolis, 1963.     

The pigments of crude cottonseed oils. I. The inhibition of color reversion in crude cottonseed oils

Summary Treatment of freshly prepared crude cottonseed oils withp-aminobenzoic acid and subsequent removal of the di-p-carboxyanilinogossypol formed makes it possible to store the oils at a relatively high temperature (37–38°C.) and for an extended period of time (30 days) without incurring any adverse changes in the refining and bleaching properties of the oils. In addition, a considerable decrease in the refining loss of the crude oil is obtained, and the stability of the bleached oil is not affected by the treatment. Spectrophotometric studies made during all phases of the chemical treatment and during the refining and bleaching procedures show that thep-aminobenzoic acid removes almost completely the gossypol-like pigments which are present in the crude oils and yields oils having the characteristic carotenoid spectrum. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.