Tocopherol concentrates by the fractional crystallization of cottonseed oil from solvents

Summary 1. Tocopherol concentrates equivalent in tocopherol content and antioxygenic activity to molecularly distilled concentrates, have been obtained from cottonseed oil by hydrogenating the oil and removing the bulk of the glycerides and sterols by low temperature crystallization from acetone. 2. High-tocopherol concentrates can be obtained only from hydrogenated oils. Completely hydrogenated oils are the best source of concentrates at crystallization temperatures down to −60° C.; below this temperature partially hydrogenated oils are equally as good. 3. A solvent-oil ratio of 8:1 by weight appears to be about the optimum. At this ratio, crystallization from acetone at the temperature of Dry Ice (−78° C.) yields a concentrate containing 34 percent tocopherols from an oil originally containing 0.05 percent tocopherols. 4. The direct addition of Dry Ice to the solvent and oil is to be avoided, since this lowers the recovery of tocopherols. 5. Petroleum naphtha and methyl ethyl ketone are less suitable solvents than acetone, because of their greater capacity for dissolving glycerides at low temperatures. Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 10 to 12, 1944. This is one of four regional research laboratories operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Antioxygenic properties of molecularly distilled fractions of peanut oil

Summary 1. Samples of unhydrogenated and hydrogenated peanut oils, which had been refined, bleached, and deodorized, were separated into two comparable series of fractions by molecular distillation. The various fractions were analyzed for tocopherols (and related chromogens) by the method of Furter and Meyer, and stability tests by the Swift method were made on the larger distilled fractions. 2. Molecular distillation at 140°, 160°, and 180° C. yielded antioxidant concentrates (presumably of tocopherols) from each oil; distillation at 240° yielded fractions almost devoid of antioxygenic substances. 3. In the unhydrogenated and hydrogenated oils, approximately 40 percent and 20 percent, respectively, of the chromogenic substances reacting in the Furter-Meyer tests were undistillable and remained in the residue comprising 10 percent of the original oil. 4. Evidence was found of the presence of distillable antioxidants other than tocopherols, which either do not respond to the Furter-Meyer test or else respond to it weakly, in proportion to their antioxygenic activity. 5. Hydrogenation of the oil had no appreciable effect on the activity of its distillable antioxidants. 6. The progressively increased addition of tocopherol-rich concentrates to fractions almost devoid of antioxidants resulted in first decreasing and then increasing the initial rate of peroxide formation in the stability tests. 7. In the case of the unhydrogenated oil, there was an optimum level of antioxidant concentration above which the addition of these substances had no stabilizing action. However, hydrogenated oil showed an increase in stability with the addition of antioxidants up to the highest level to which the concentration of the latter was carried (approximately 0.15 percent, calculated asa-tocopherol). Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 12 to 14, 1943.     

Dilatometric investigations of fats II. Dilatometric behavior of some plastic fats between 0° C. and their melting points

Summary 1. Dilatometric curves between 0°C. and their melting points have been obtained for the following fats: lard, butterfat, cottonseed oil, peanut oil, a commercial margarine oil, a commercial all-hydrogenated vegetable shortening, three samples of soybean oil hydrogenated to different degrees, a hard butter fractionally crystallized from hydrogenated peanut oil, a mixture of tristearin and soybean oil, and a synthetic fat containing equal molar proportions of stearic and oleic acids. 2. The dilatometric curves, of volume change in the fat against temperature, were in every case composed of a series of straight lines, separated by sharp breaks or transition points. 3. The number of linear sections in the dilatometric curves corresponded in a general way with the known degree of complexity in the glycerides of the fats, and varied from two in the case of the relatively simple stearic-oleic glyceride mixture, to at least seven in the case of the all-hydrogenated shortening. Since each break in the curve must correspond to the disappearance of a distinct class of solid glycerides or glyceride complexes, the application of dilatometry to the qualitative and quantitative determination of glyceride composition in fats is suggested. 4. Only two of the fats examined, the mixture of tristearin and soybean oil, and the synthetic stearicoleic glyceride mixture, exhibited polymorphism, even after rapid solidification in ice water. Presented before the American Oil Chemists’ Society Meeting, New Orleans, Louisiana, May 10 to 12, 1944. This is one of four regional research laboratories operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Dietary fat composition and tocopherol requirement: II. Nutritional status of heated and unheated vegetable oils of different ratios of unsaturated fatty acids and vitamin E

In studies conducted on male and female rats and involving evaluation of growth, reproductive and lactation performances and of lipid peroxidation, no evidence could be found for the need for added vitamin E (a-tocopherol) over and above that naturally present as tocopherols in the vegetable oils investigated. These oils are in common usage in industry, i.e., liquid nonhydrogenated cottonseed oil, a lightly hydrogenated cottonseed oil and a hydrogenated soybean oil shortening. The ratio of polyunsaturates to total tocopherol in the test oils varied from 640:1 to 9:1. Even those oils obtained from a commercial frying operation after a steady state had been attained contained sufficient vitamin E to meet dietary requirements. Results of in vitro peroxide hemolysis tests conducted on the red blood cells of the test animals did not correlate well with biological performance.     

Molecular distillation of some Indian vegetable oils

Summary 1. Karanja, malkanguni, undi, and sesame oils were molecularly distilled, and the fractions obtained were characterized for their physical and chemical constants. 2. Generally, the first few fractions were found to be rich in odor, free fatty acids, and unsaponifiable matter. 3. Sesamin could be isolated from the first fraction of molecularly distilled sesame oil by crystallization. 4. Karanjin and pongamol were similarly separated from the first fraction of molecularly distilled karanja oil. 5. With malkanguni oil there was some fractionation of the glycerides. 6. Elimination curves of karanja, malkanguni, undi, and sesame oils are given.     

Studies in the Glyceride Composition of Partially Hydrogenated Rearranged Glycerides of Cottonseed Oil

The directed rearrangement reaction in solvents of partially hydrogenated cottonseed oil was investigated with special reference to the influence of polarity of solvents and amount of trisaturated glycerides formed. The results as obtained by selective enzymatic hydrolysis, gas liquid chromatography and infrared spectrophotometry of the whole fat triglycerides and of the corresponding monoglycerides of cottonseed oil and partially hydrogenated cottonseed oil, before and after directed interesterification, indicate a general trend of the increase of the saturated fatty acyl radicals in the 2-position of the glyceride moiety with the corresponding decrease of the unsaturated acids. The considerable decrease in the concentration of cis unsaturated acid in the 2-position of the triglycerides of partially hydrogenated cottonseed oil has been observed after the directed rearrangement reaction with the simultaneous enrichment of trans unsaturated acid. It was also observed that cottonseed oil does not show any plasticity, whereas after directed interesterification it shows remarkable plasticity. The plasticity of partially hydrogenated cottonseed oil is further diminished after directed rearrangement reaction.     

Thermal properties of fats and oils

Summary 1. The heat content of a quickly chilled sample, and that of a slowly chilled and tempered sample, of almost completely hydrogenated cottonseed oil, has been measured over a temperature range within which there is in each case complete transformation of the oil from a solid to a liquid form. 2. Heat capacity data have been calculated for the liquid oil and for the quickly chilled and the tempered solid oil. Equations expressing the changes in heat capacity with temperature have been derived. A correlation of the heat capacity data on highly hydrogenated cottonseed oil and similar data previously obtained on unhydrogenated cottonseed oil, and on partially hydrogenated oil, in both liquid and solid states, is presented. 3. The heat of fusion calculated for the quickly chilled and for the tempered solid oil is given. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

The effect of various concentrations of tocopherols and tocopherol mixtures on the oxidative stability of a sample of lard

A comparison was made of α-, γ-, and δ-tocopherol at various concentrations and a mixture of these tocopherols representing the average tocopherol content of peanut oil on the oxidative stability of lard at 97C. Uptake of oxygen was used to indicate the length of the induction period. The antioxidant effectiveness of the tocopherols was found to increase in the order α, δ, γ. The antioxidant efficiency decreases with increasing concentrations of tocopherols such that addition of any single tocopherol above a concentration of 250 μg/g has little effect on oxidative stability. A mixture equivalent to that of an average peanut oil sample, containing 150 μg/g of α-tocopherol and 250 μg/g of γ-tocopherol and 15 μg/g of δ-tocopherol was found to be no more stable than one containing 250 μg/g of γ-tocopherol alone.     

Beef tallow in shortening preparations

Summary Experimental shortenings were prepared from various mixtures of tallow and cottonseed oil. Three series of shortenings were produced by somewhat different procedures: a) mixtures of tallow and cottonseed oil were hydrogenated and then catalytically rearranged; b) mixtures of hydrogenated tallow and cottonseed oil were rearranged; and c) mixtures of hydrogenated tallow and cottonseed oil were rearranged in the presence of 0.43% glycerine. Certain combinations and treatments of tallow and cottonseed oil produced shortenings which compared reasonably well with standard vegetable shortenings. Presented at the 29th Fall Meeting of The American Oil Chemists’ Society, Philadelphia, Pa., Oct. 10–12, 1955. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Phase relations pertaining to the solvent winterization of cottonseed and peanut oils in acetone

Summary and Conclusions Systematic physical chemical data on the solventwinterization behavior of cottonseed and peanut oils with acetone have been obtained which should serve as a basis for selecting the conditions necessary for the effective solvent winterization of these oils in acetone. Cottonseed and peanut oils are only partially miscible with acetone below certain temperatures which have been determined. In peanut oil this phenomenon may interfere with the winterization process within a certain range of concentrations. For cottonseed oil however the separation into two liquid phases does not occur until some 5°C. below the temperature required for adequate winterization. Complete data for a 3-hour holding-time have been obtained for three cottonseed oils ranging in iodine value from 106.1 to 116.4. Tables and graphs have been constructed to show the effect of oil-solvent ratio, chilling temperature, holding-time, agitation, and iodine value of the original oil on the percentage of solid removed and on the degree of winterization and iodine value of the winterized oil. Similar data have been obtained for a refined peanut oil insofar as possible without interference from separation into two liquid phases. It seems probable that if acetone were used as the winterization solvent for peanut oil, the separation into two liquid layers and the sensitivity of this phenomenon to moisture might be a source of processing difficulties especially if filtration instead of centrifugation were used to separate the solid from the supernatant. Resigned: September 2, 1949. Resigned: August 13, 1948. Resigned: January 28, 1949. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Thermal properties of fats and oils

Summary 1. Melting points and x-ray diffraction patterns have been determined for cottonseed oil hydrogenated to an iodine value of less than 1, and for a very pure sample of tristearin. 2. Contrary to the observations of previous investigators, the x-ray patterns indicate a well-defined crystal structure with a sharp long spacing and a single sharp short spacing in the lowest-melting form of tristearin. A new pattern, with two short spacings and a long spacing, was observed in tristearin of intermediate melting point. 3. Four polymorphic forms of the hydrogenated cottonseed oil were detected. The x-ray pattern of the lowest-melting form of the hydrogenated oil was similar to that of the correspopnding form of tristearin. The pattern of the highest-melting form of the hydrogenated oil differed from that of either tristearin or β-palmitodistearin, the major components of the oil. Distinctive patterns for the intermediate forms of the hydrogenated oil could not be obtained, presumably because of the instability of the lower melting forms at room temperature. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Biological effects of the polymeric residues isolated from autoxidized fats

Summary There is increasing evidence that the abnormal nutritional properties of highly autoxidized fats are related to the polymers which develop during autoxidation. Lard and cottonseed oil were aerated at 95°C. for 200 hrs. and molecularly distilled; and the residue fractions, non-volatile at 275 to 300°C., were studied. Diets containing 20% of autoxidatively produced polymeric residue, fed to albino rats, led to diarrhea and rapid death, but when this residue was reduced to 10%, most of the animals were gradually able to tolerate it. At the 4 or 7% level it was well tolerated, but growth was reduced. There were no distinctive histological lesions, and withdrawal of the polymer permitted immediate realimentation without evidence of subsequent injuries. The polymeric residue from autoxidized cottonseed oil exerted a greater growth-depressant effect than that from lard, and the latter, more than that from a hydrogenated vegetable oil used for deep-fat frying for 80 hrs. at 190°C. Addition of fresh fat to the polymeric residues decreased their growth-depressant effect. When rats were fed a measured amount of diet sufficient to maintain their weight, the caloric requirement necessary for weight maintenance gradually decreased. When the dietary fat source consisted of polymeric residue to the extent of 4 to 10%, the caloric requirement for weight maintenance decreased relatively little, if at all. The polymeric residue from autoxidized lard was, in this respect, as effective as that from autoxidized cottonseed oil. This paper is XXI in the series “Reactions of Fatty Materials with Oxygen.” Paper XX is reference 18. Presented at the Fall meeting of the American Oil Chemists’ Society, Philadelphia, Pa., October 10–12, 1955. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Modification of Fats by Lipase Interesterification I: Changes in Glyceride Structure

Blends of refined cottonseed oil and fully hydrogenated soybean oil were subjected to interesterification reactions catalyzed by Rhizomucor miehei and Candida antartica lipases in a solvent free system. The interesterification decreased the levels of triunsaturated and trisaturated triglycerides and increased the amounts of mono- and disaturated triglycerides in the blends. The triglyceride products obtained by the two enzyme preparations were similar in composition but differed in the proportions: levels of high melting glycerides were higher in the products obtained with C. antartica lipase. The amounts of hydrolysis products formed depended on both the choice of enzyme and the substrate composition. The content of 1,3-diglycerides formed exceeded that of 1,2-diglycerides and low levels of monoglycerides were formed during the reactions.     

Quantitative measure of selectivity of hydrogenation of triglycerides

Graphs have been prepared using a digital computer that allow the quantitative determination of the degree of selectivity for the hydrogenation of cottonseed, peanut, corn, soybean and linseed oils. Use of these graphs requires only a knowledge of the composition of the initial (unhydrogenated) oil and that of the hydrogenated oil plus simple calculations. If the exact composition of the initial oil is unknown, a typical composition can generally be assumed.     

Studies of unsaponifiables in several vegetable oils

The unsaponifiable fractions of soybean, cottonseed, coconut, olive, and avocado oils have been studied in detail. The oils differed in the contents of total unsaponifiables, squalene, tocopherols, and sterols and also in the composition of the tocopherol and sterol fractions. The presence of absence of individual unsaponifiable components may help in establishing the identity of each of the investigated oils and in detecting of admixture by another oil.     

Evaluation of peanut and cottonseed oils for deep frying

A comparative study of cottonseed and peanut oils for frying of potato chips was undertaken. Industrial scale frying was conducted for 5 days with cottonseed and 5 days with peanut oil and frying oils and chips were sampled twice a day. Frying oils and oils extracted from stored chips were analyzed for ultraviolet absorption (A₂₃₂ and A₂₆₈), peroxide and acid values. Tocopherol and tertiary butylhydroquinone levels were determined by high performance liquid chromatography. Chips stored at room temperature for 12 weeks were organoleptically evaluated. During the first 20 hr frying the A₂₃₂, free acid and peroxide values of cottonseed oil increased rapidly, exceeding that of peanut oil, which increased moderately. For both oils, constant values were attained during the next 80 hr period, followed by moderate increases during the last 23 hr. Peanut frying oil lost 55% of its tocopherols and 54% of its tertiary butylhydroquinone during frying (103 hr), whereas cottonseed frying oil retained these compounds at the original levels. Tocopherols were also better retained in chips fried in cottonseed oil than in peanut oil. The fatty acid patterns of frying oils and oils extracted from chips did not show significant changes due to frying and storage, respectively. These results, therefore, suggest that cottonseed oil is sufficiently stable to be used as a substitute for peanut oil in deep frying.     

Spectrophotometric estimation of soybean oil in admixture with cottonseed and peanut oils

Conclusion A spectrophotometric method has been described for the determination of soybean oil in admixture with cottonseed oil. The method provides a simple and rapid means of detecting gross adulteration of one oil with another and permits an accurate determination of linolenic acid for use as a criterion of the economic value of an oil mixture and as a guide in oil processing. The factor limiting the precision of the method is variation in composition of the cottonseed and soybean oils in the mixtures to be analyzed. Variations in composition affect the proportion of measured triene conjugation, due to the linolenic acid content of the soybean oil and the apparent linolenic acid content of the cottonseed oil. Thus, for unknown mixtures only average value corrections can be made for apparent linolenic acid content and the accuracy of a particular analysis will depend upon how well the composition of the oils in the particular mixture follows those of the average mixture. The method described can be extended to mixtures other than those of soybean and cottonseed oils. Thus, soybean oil may be determined in admixture with a peanut oil. In general, any oil which has an unsaturated fatty acid capable of producing triene conjugation upon alkali isomerization can be determined in the presence of any other oil containing no appreciable quantity of unsaturated fatty acids which can produce triene conjugation by such treatment. Presented before The American Oil Chemists’ Society, New Orleans, Louisiana, May 10–12, 1944. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Additional physical properties of diglyceride esters of succinic and adipic acids

Summary Diglycerides of the fat-forming acids yield, on esterification with succinic, adipie, and other shortchain dibasic acids, a poteutially useful series of compounds ranging from hard, high-melting waxes to viscous oils which will not crystallize. A number of the properties of these compounds were determined in carlier investigations. In the present investigation additional properties of the 1,3-diolein and 1,3-distearin esters of succinic and adipic acids were determined. Surface and interfacial tensions were measured and found to be similar to those of cottonseed oil. The smoke points also were found to be similar to that of cottonseed oil. The ability of the compounds to thicken cottouseed oil was measured and found to be somewhat better than that of highly hydrogenated cottonseed oil at levels above about 12%, and the mixtures were relatively resistant to fat leakage. In hardness the distearin esters of succinic and adipic acid were comparable to carnauba wax and were over twice as hard as highly hydrogenated cottonseed oil. Permeability to water vapor was found to be greater than that of highly hydrogenated cottonseed oil and carnauba wax and about equal to that of cocoa butter. Presented at the 33rd Fall Meeting, American Oil Chemists' Society, Los Angeles, Calif., September 28–30, 1959. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Flavor stability of soybean oil. 1. The role of the non-saponifiable fraction

Summary It has been found that the addition of the nonsaponifiable extract of hydrogenated soybean oil to either refined cottonseed oil or refined peanut oil caused these oils to develop odors and flavors characteristic of reverted soybean oil. The non-saponifiable material from linseed oil did not produce a similar effect. When the non-saponifiable extract of hydrogenated soybean oil was added to mineral oil, a sweet, syrupy odor and flavor developed. By selective absorbents it was possible to produce a much greater improvement in hydrogenated than in unhydrogenated soybean oil. These observations are discussed in terms of their relationship to the various theories on the mechanism of reversion.     

Evaluation of Beeswax,Candelilla Wax,Rice Bran Wax,and Sunflower Wax as Alternative Stabilizers for Peanut Butter

Four natural waxes were evaluated as stabilizers in peanut butter. The potential advantage of using natural waxes would be the replacement of current stabilizers such as hydrogenated or tropical oils, thereby reducing saturated fats and satisfying clean label requirements. Beeswax (BW), candelilla wax (CLW), rice bran wax (RBW), sunflower wax (SFW), and a commercial peanut butter stabilizer, hydrogenated cottonseed oil (HCO), were added to three natural peanut butter brands at levels ranging from 0.5% to 2.0% (w/w) and tested for accelerated oil release, long-term stability, firmness, and rheology. At levels ≥0.5%, all waxes improved oil-binding capacity (OBC). SFW and HCO had the highest OBC, followed by RBW, CLW, and BW. All waxes reduced the amount of oil separation after 6 months at 22 ± 2 °C. HCO followed by SFW reduced oil separation the most, but there were no significant differences between stabilizers at 1–2%. Firmness and yield stress increased with increasing stabilizer level, with SFW increasing firmness the most, followed by HCO, RBW, and CLW, while BW had the lowest effect. The results indicate that the waxes may be feasible replacements for hydrogenated oils as peanut butter stabilizers, but levels would need to be optimized depending on the product characteristics and wax type.