Measurement of the consistency of plastic vegetable fats

Summary 1. An improved micropenetrometer is described, by means of which it is possible to measure the consistency of fats with a high degree of precision. 2. The intelligent use of a micropenetration method requires some consideration of the theory of plasticity in fats. This theory is briefly discussed. 3. The influence of various factors on the consistency of solidified fats has been investigated, and as a result of this investigation a standard technique for making micropenetration tests is proposed. 4. Micropenetration data are recorded on cottonseed, peanut, and soybean oils hydrogenated to different degrees, on cottonseed oil blended with various proportions of highly hydrogenated oil, and on various commercial samples of shortening and margarine. 5. A quick micropenetration method, applicable as a control in the hydrogenation of fat products, is described.     

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.     

Tempering triglycerides by mechanical working

The tempering of fat products to convert their components to stable polymorphs is an important and a sometimes troublesome problem in the manufacture of these products, particularly chocolate and chocolate-type confections. It has been found that a solid-to-solid transformation to the stable polymorphs can be effected by mechanical working consisting of extrusion under pressure. With a fat of relatively few components, such as cocoa butter, evidence of the transformation can be obtained from X-ray diffraction patterns. For more complex fats, hardness and melting characteristics must be considered. There is evidence that mechanical working is also effective in the transformation of a cocoa butter-like fat made from hydrogenated cottonseed oil and olive oil, and in the transformation of highly hydrogenated cottonseed oil. Mechanical working to effect polymorphic transformation is also effective with products containing the fats mentioned. Presented at the 35th Fall Meeting of the American Oil Chemists' Society, Chicago, Illinois, October 30–November 1, 1961. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Consistency of mixtures of cottonseed and Paraguayan palm kernel oils

Summary A palm kernel oil, mbocaya, possessing a relatively high iodine value, approximately 30, is being produced in Paraguay. Production can be expanded. One possible use for the oil is as a component of shortenings. As expected, consistency measurements showed the oil to be unsuited for conversion to shortening of the all-hydrogenated type. Blends with hydrogenated cottonseed oil yielded products having acceptable consistency characteristics. However, for a given consistency, the proportion of hydrogenated cottonseed oil needed was greater than that needed for a comparable blend with cottonseed oil. The difference was attributed to the formation of solid solutions or mixed crystals in the latter blend. A mixture of hydrogenated palm kernel oil and cottonseed oil was prepared and found to possess consistency characteristics better than those of a typical shortening of the all-hydrogenated type. Presented at the 28th Fall Meeting of the American Oil Chemists’ Society, Minneapolis, Minn., Oct. 11–13, 1954. Formerly Chief Chemist, Coindu, Asuncion, Paraguay. Sponsored by Institute of Inter-American Affairs under Point IV program. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

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.     

Modification of vegetable oils. XIV. Properties of aceto-oleins

Summary Pure 1,2-diaceto-3-olein was prepared by acetylating mono-olein. A mixture of aceto-oleins was prepared by acetylating a mixture of mono-, di-, and trioleins derived from commercial oleic acid. Several natural oils were acetylated either by ester-ester interchange with triacetin or by glycerolysis followed by acetylation. The various products were examined for cloud and solid points, point of complete melting, and consistency. The 1,2-diaceto-3-olein, which contains 19.5% of acetyl group on a weight basis, has a melting point of −18.3°C. while the mixture of aceto-oleins, which contained 14.3% of acetyl on a weight basis, melted at −24°C. Acetylation of the natural oils raises in most instances their cloud and solid points and point of complete melting, but it also greatly increases their plasticity at lower temperatures. Aceto-compounds were used to plasticize highly hydrogenated cottonseed oil. These mixtures were prepared so that they possessed the consistency of margarine oil at room temperature. These mixtures, when compared with partially hydrogenated oil, butterfat, or a mixture of cottonseed oil and hydrogenated cottonseed oil, were softer below room temperature and firmer above room temperature. A margarine-like product containing 79% of aceto-olein and 18.5% of highly hydrogenated cottonseed oil had a practically constant consistency over the temperature range of −15° to 49°C. (5° to 120°F.). Presented at the 26th Fall Meeting of the American Oil Chemists' Society, Cincinnati, O., Oct. 20–22, 1952. 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.     

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.     

Margarine and shortening oils by interesterification of liquid and trisaturated triglycerides

Liquid vegetable oils (VO), including cottonseed, peanut, soybean, corn, and canola, were randomly interesterified with completely hydrogenated soybean or cottonseed hardstocks (vegetable oil trisaturate; VOTS) in ratios of four parts VO and one part VOTS. Analysis of the reaction products by high-performance liquid chromatography showed that at 70°C and vigorous agitation, with 0.5% sodium methoxide catalyst, the reactions were complete after 15 min. Solid-fat index (SFI) measurements made at 50, 70, 80, 92, and 104°F, along with drop melting points, indicated that the interesterified fats possess plasticity curves in the range of commercial soft tub margarine oils prepared by blending hydrogenated stocks. Shortening basestocks were prepared by randomly interesterifying palm or soybean oil with VOTS in ratios of 1:1 or 3:1 or 4:1, respectively. Blending of the interesterified basestocks with additional liquid VO yielded products having SFI curves very similar to commercial all purpose-type shortening oils made by blending hydrogenated stocks. Other studies show that fluid-type shortening oils can be prepared through blending of interesterified basestocks with liquid VO. X-ray diffraction studies showed that the desirable β′ crystal structure is achieved through interesterification and blending. Presented at AOCS Annual Meeting & Expo, Atlanta, Georgia, May 8–12, 1994.     

Crystallization of hydrogenated sunflower-cottonseed oil

Crystal structures formed during solidification of hydrogenated cottonseed oil, sunflowerseed oil and their blends were analyzed by using an X-ray diffraction technique, differential scanning calorimetry (DSC) and polarized light microscopy. Temperatures and times of crystallization under conditions which tend to produce β′ type structures were determined in terms of refrigeration parameters. Microscopy with polarized light also helped clarify some aspects of the tridimensional network of crystals that contribute to the consistency of products made from hydrogenated oils.     

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.     

Solubility of tristearin and hydrogenated cottonseed oil in certain aceto- and butyroglycerides

Summary Tristearin, triolein, 1,2-diaceto-3-olein, an acetoolein product, and 1,2-dibutyro-3-olein were prepared. Also a commercial, refined, and bleached cottonseed oil was hydrogenated to obtain products having iodine values of 29.3 and 1.1. Solubility measurements were made for the mixtures tristearin-triolein, tristearin-1,2-diaceto-3-olein, tristearin-1,2-dibutyro-3-olein, and for hydrogenated cottonseed oils in the aceto-olein product and cottonseed oil. In mixtures containing from 0.18% to approximately 30% of tristearin the solubility on a weight basis was unaffected by the nature of the oil. On a mole fraction basis the tristearin was most soluble in the triolein and least soluble in the 1,2-diaceto-3-olein. Hydrogenated cottonseed oil appeared to be about equally soluble, on a weight basis, in the aceto-olein product and cottonseed oil. Presented at the 45th annual meeting of the American Oil Chemists’ Society, San Antonio, Tex., April 12–14, 1954. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, United States Department of Agriculture.     

Modification of vegetable oils

Summary 1. An investigation has been made of low-temperature crystallization from organic solvents as a means of effecting practical separations of the solid and liquid acids of unhydrogenated and hydrogenated cottonseed oils. 2. At any fixed temperature the most efficient separations were obtained in the highly polar solvents, acetone and methyl acetate. However, it was possible in any case to make nonpolar petroleum naphtha (Skellysolve B) fully equivalent to the polar solvents simply by conducting the crystallization at a temperature approximately 10° F. lower than that employed with the polar solvents. Ethyl acetate and methyl ethyl ketone were intermediate between petroleum naphtha and acetone or methyl acetate in their effectiveness. 3. By employing a solvent-fatty acid ratio of 4 to 1 by weight and conducting crystallizations at 5° F. or lower from acetone and −5° F. or lower from petroleum naphtha, the liquid fatty acids from unhydrogenated cottonseed oil could be reduced to below −2° C. in titer and to below about 3 per cent in saturated acid content. Under these conditions there was no appreciable crystallization of oleic acid. 4. At a solvent-fatty acid ratio of 6 to 1 and the same temperatures (5° F. for acetone and − 5° F. for petroleum naphtha) equally good separations could be made of the saturated fatty acids present in the mixed acids from hydrogenated cottonseed oil (I.V.=70). Separation of “iso-oleic” acids from the fatty acids of the hydrogenated oil took place over a wide range of temperatures, beginning at 35° F. in acetone and at 25° F. in petroleum naptha, and being incomplete (according to Twitchell analyses of the liquid acids) in either solvent at −15° F. However, the bulk of the higher melting iso-oleic acids was precipitated as the temperature approached −5° F. in acetone and −15° F. in petroleum naphtha. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Permeability of some fat products to moisture

Summary Films of cocoa butter, highly hydrogenated cottonseed oil, mixtures of highly hydrogenated cottonseed oil and cottonseed oil, chocolate liquor, and sweet milk chocolate were prepared; and their permeability to water vapor was determined by the cup method. The permeability constant was calculated in terms of grams of water diffusing through a centimeter cube in one second under a vapor pressure gradient of one millimeter of mercury across the cube. Under the test conditions employed, the permeability constant for cocoa butter at room temperature was found to vary from 5.8×10⁻¹² to 81.6×10⁻¹². The permeability constants for the highly hydrogenated cottonseed oil and the cocoa butter, under comparable conditions at room temperature, was found to be approximately 1.3×10⁻¹² and 33×10⁻¹², respectively. From data obtained with cocoa butter it was concluded that the permeability constant increased with moderate increases in film thickness. Polymorphism was found to have a large effect on permeability, an approximately 15-fold difference was found between quickly chilled and tempered films of cocoa butter at 3°C. (37.4°F.). The percentage of liquid component in the fat was found to have a large effect on permeability. The increasing of the percentage of liquid cottonseed oil in highly hydrogenated cottonseed oil from 0 to 40% increased the permeability constant from 1.3×10⁻¹² to about 420×10⁻¹². The permeability of chocolate liquor and sweet milk chocolate at room temperature was increased greatly when the relative humidity on the wet side of the films was increased to 100%. The nonfat components absorbed enough moisture to impair the structure of the film. Presented at the 32nd Fall Meeting of the American Oil Chemists' Society, Chicago, Ill., October 20–22, 1958. Fellow, National Confectioners' Association. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Molecular distillation of a hydrogenated cottonseed oil and certain characteristics of the distilled fractions

Summary 1. A hydrogenated cottonseed oil has been molecularly distilled, and the distilled fractions examined. 2. Fractionation of a molecularly distilled oil occurs, as is to be expected, on the basis of variations in molecular weight of the glycerides. The composition of cottonseed oil is such that there is a considerable separation of the glycerides according to their degree of unsaturation. The composition of peanut oil is such that similar separation can only be slight. Soybean oil is in this respect intermediate between cottonseed oil and peanut oil. 3. Molecular distillation of hydrogenated cottonseed oil causes a segregation of tocopherols and related compounds similar to that observed in peanut oil. However, the fractions first distilled from the oil are relatively weak in antioxygenic properties. It appears probable that their lack of effectiveness is due to the presence of unknown substances capable of inhibiting or counteracting the action of tocopherols. However, the presence of substances other than tocopherols, which respond to or interfere with the Emmerie-Engel test is not to be excluded. The tocopherols in the potent fractions are more effective thana-tocopherol, but less effective than γ-tocopherol. 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.     

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.     

Evaluation of Trans and Essential Fatty Acid Content in Some Egyptian Consumer-Available Hydrogenated Fats

The fatty acid composition of cottonseed and com oils was determined before and after the technological hydrogenation process. In hydrogenated cottonseed and corn oils the essential fatty acid content (linoleic, 18:2 ω⁶) was decreased while the trans-18:1 acid was increased as compared to the native oils. The trans as well as the essential fatty acid contents in some consumeravailable hydrogenated fats were evaluated. The composition of cis and trans monoene isomers were also determined. This study revealed that some of the Egyptian consumer-available hydrogenated fats contain considerable amounts of trans acids.     

Comparison of Soybean and Cottonseed Oils upon Hydrogenation with Nickel,Palladium and Platinum Catalysts

There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In the interest of understanding the TFA levels, hydrogenation was carried out in this work on soybean oil and cottonseed oil at two pressures (2 and 5 bar) and 100 °C using commercially available Ni, Pd, and Pt catalysts. The TFA levels and the fatty acid profiles were analyzed by gas chromatography. The iodine value of interest is ~70 for all-purpose shortening and 95–110 for pourable oil applications. In all cases, higher hydrogen pressures produced lower levels of TFA. In the range of 70–95 iodine values for the hydrogenated products, the Pt catalyst gave the least TFA, followed closely by Ni, and then Pd, for both oils. For all three catalysts at 2- and 5-bar pressures and 70–95 iodine values, cottonseed oil contained noticeably less TFA than soybean oil; this is probably because cottonseed oil contains a lower total amount of olefin-containing fatty acids relative to soybean oil. Approximate kinetic modeling was also done on the hydrogenation data that provided additional confirmation of data consistency.     

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.     

The specific and latent heats of fusion of some vegetable fats and oils

Summary The specific heats of several vegetable oils have been determined by a more exact procedure than those which seem to have been used heretofore. Values slightly higher than the literature figures were obtained, that is, an average value of 0.53 was determined as compared to reported results of 0.50. The specific heat of cottonseed oil with respect to temperature increases slightly with elevating temperatures. The specific heats at different temperatures were not determined on the other oils, but likewise, these probably show no significant variation in specific heat with respect to temperature in the range 21° to 100°C. The specific heats of completely solid vegetable fats are believed to be reported for the first time. These values are about the same for such different stocks as completely hardened palm and sunflower oils, and their values are approximately one-half that of the liquid, that is, 0.28 as compared to 0.53. The latent heats of fusion of a number of fats have also been determined by what is thought to be a satisfactory procedure. Theoretical aspects and empirical results are given to show that the latent heat of fusion varies with the temperature when two phases are present, and that for this reason, any references to the latent heat of fusion should be accompanied by temperature limitations. This is not so important, however, when the specimen is completely solid at the temperature in question. The data and graphs presented show the general variation in latent heat of hardened cottonseed oil at one temperature with respect to iodine value.