Vernon L. Frampton

Bleaching of off-colored cottonseed oils

The adsorption of fixed red pigments from refined off-colored cottonseed oil by several adsorbents is described by the empirical Freundlich adsorption isotherm. Numerical values for the coefficient and the exponent in the Freundlich equation were determined for several oils and several adsorbeuts. Activated alumina was found to be a superior adsorbent for removing the red color bodies. It was observed that the variations from oil to oil in the numerical values of the coefficient and the exponent of the Freundlich equation were smaller for the several aluminas than they were for the other adsorbents studied. The particle size and moisture contents of the alumina, and the temperature of activated adsorption were of importance in determining the effectiveness with which the red color bodies were removed from the oils. The conditions required for optimum bleaching with alumina had no detectably adverse effect on oil quality.

Note on gossypol and its relation to color fixation in cottonseed oil

Summary1.The crude oils studied contained from 0.00 to 0.04% gossypol.2.Much of the gossypol added to crude cottonseed oils disappeared in one hour.3.The disappearance of gossypol from refined, bleached, and deodorized cottonseed oil, from highly purified tripelargonin, and from ethyl acetate is demonstrable after the lapse of one hour.4.It is suggested that the initial reaction of gossypol in the oils is an ester exchange reaction.5.It is further suggested that secondary reactions result in the production of a red coloration product that is not removable from the oil by the standard refining and bleaching methods.

Reactivation of alumina used in bleaching of off-colored cottonseed oils

Spent alumina recovered from bleaching cottonseed oil with activated alumina can be reactivated by simple incineration at 400–700°C. and remoistening to at least 10% moisture content. The cycle of bleaching and regeneration may be repeated indefinitely with only nominal mechanical losses of alumina. Losses of refined oil by entrainment in activated alumine need be only 0.5%.

Binding of gossypol under conditions of complete rupture of the pigment glands

SummaryThe “free” gossypol of cooked cottonseed meats is composed of gossypol and of “gossypol-like pigments,” which are soluble in 70% aqueous acetone. The “gossypol-like pigments” may account for 30 to 100% of the “free” gossypol as determined by the A.O.C.S. method.Thorough comminution, followed by prolonged cooking, results in reduction of all the pigments in cotton-seed meats. “Free” gossypol is not completely eliminated, but the gossypol level, as determined by the benzene transfer method, may be reduced to zero.“Gossypol-like pigments” are converted into gossypol by the action of hot aqueous hydrochloric acid.Good agreement is observed between the data for “total” gossypol, as determined through the use of the A.O.C.S. oxalic acid method and through the use of hot aniline.

Lysine, gossypol, and nitrogen solubility in chemically treated cottonseed meals

The effects of treatment of commercial prepress-solvent extracted and direct-solvent extracted cottonseed mares with several chemical agents and solvents were studied. The analytical results for “free” and “total” gossypol of the finished meals show that treatment with aliphatic amines, followed by extraction with a suitable solvent, removed large proportions of the “free” as well as “bound” gossypol. This reduction of “free” and “bound” gossypol was accompanied, in some experiments, by an increase in the nitrogen solubility and available lysine, as compared with the results obtained with the untreated air-dried marcs. The available lysine contents of the treated mares was significnatly correlated with the nitrogen solubility in 0.02N aqueous NaOH.

Spontaneous conversion of gossypol to anhydrogossypol

An alkali-fast pigment is produced at room temperature when gossypol is dissolved in ethyl acetate. This pigment has been isolated from ethyl acetate as an orange crystalline material and identified as anhydrogossypol. The identity was established by identity of the infrared spectra with that of authentic anhydrogossypol; by elementary composition; by mixture-melting point behavior with authentic anhydrogossypol; and by the identity of the aniline derivatives produced from the orange crystalline product from ethyl acetate and authentic anhydrogossypol.

Kinetic study of gossypol fixation in cottonseed oil

SummaryIt was shown in experiments carried out under anaerobic conditions that the fixation of gossypol in cottonseed oil is a reaction of the second order with respect to gossypol. In other words, the rate of fixation is proportional to the square of the gossypol concentration in the oil. The rate of fixation is temperature-dependent and increases 22-fold with an increase in temperature from 40° to 80°C.

Lipids of the cottonseed

Summary1.Consistent results are obtained with the refractometric method of oil assay, but they are not in agreement with those obtained by the official methods involving extraction with diethyl ether or petroleum ether.2.The composition of the extract obtained with cottonseed using petroleum ether varies from specimen to specimen.3.The yield of lipid-soluble materials obtained on extraction of cottonseed with several solvents is different with each solvent.4.Heat treatment of cottonseed reduced the quantity of lipids which could be extracted with petroleum ether.5.Absorption spectra of chloroform solutions of cottonseed extracts obtained with several solvents show qualitative differences in the material obtained with the different solvents. Iodine numbers and indices of refraction are also different.6.Distinct qualitative differences are noted in the different fractions obtained on the extraction of cottonseed with chloroform. These differences are apparent in the absorption spectra and iodine numbers of the fractions.

On the extraction of oil from raw comminuted cottonseed kernels with the acetone-hexane-water azeotrope

The effects of particle size on the rate of ex-traction of oil from raw comminuted cottonseed kernels with the acetone-hexane-water azeotrope were examined. Five samples of cottonseed of different average particle sizes and three extrac-tion times were used in the investigation. The particles were comminuted in such a manner as to be, as a first approximation, essentially spher-ical in shape ; the concentration gradient of oil in the particles was found to follow the relationship L =r-A +B where L is the oil content of the extracted seed, r is the particle radius, and A and B are constants. The establishment of the concentration gradient was extremely rapid (within 10 seconds), and the constants A and B assume the same values for each of the three extraction times employed. These two facts in-dicate that mass oil movement in the particles is a dilatation and occurs too rapidly for diffusion phenomena to be evident.

Bleaching of refined cottonseed oil with modified alumina adsorbents

Activated aluminas, modified by treatment with inorganic and organic acids were tested for their efficiency as bleaching agents and for their ability to eliminate the response of refined cottonseed oil to the Halphen test. The best of these adsorbents, an alumina containing catalytic amounts of adsorbed sulfurous acid, is a bleaching agent that is effective in removing problem pigments from offcolored cottonseed oils, and is superior to activated aluminas in removing green chlorophyll-like pigments. Oils bleached with the catalytic adsorbent are negative to the Halphen test, and are free of sulfur.Study of the rate of reduction in the Halphen test response as a function of bleaching time and temp indicated that sulfurous acid treated alumina has a pronounced catalytic effect. The Halphen test response is eliminated during a 30 min bleaching period at 225C. Deodorization conditions employed had little effect on Halphen test reduction.