Showing papers in "Journal of the American Oil Chemists' Society in 1952"

Standardization of spectrophotometric methods for determination of polyunsaturated fatty acids using pure natural acids

Abstract: Spectrophotometric methods of analysis for the polyunsaturated constituents of oils and fats have been carefully restandardized for several conditions of alkali-isomerization, using purified methyl esters of linoleic, linolenic, and arachidonic acids prepared by physical rather than by chemical means A number of vegetable oil and animal fat samples were subjected to spectrophotometric analysis, and the results based on natural and on bromination-debromination fatty acid standards were compared The natural fatty acid standards lead to significantly higher accuracy and their use in the spectrophotometric analysis of natural fatty materials is strongly recommended Results obtained under different conditions of isomerization were in satisfactory agreement An isomerization time of 45 minutes is recommended rather than 25 or 30 minutes The glycerol-air technique is preferred for general use because of its simplicity and high precision The ethylene-glycol-nitrogen technique is a close second choice because of the greater transparency of reagent blanks

Surface and interfacial tensions, viscosities, and other physical properties of some n-aliphatic acids and their methyl and ethyl esters

Abstract: 1. Determinations of surface tension, interfacial tension against water, viscosity, density, and refractive index were made at 75°C. for the saturated, evennumbered,n-fatty acids from C2 through C18 and for the corresponding methyl and ethyl esters. The typical effect of temperature on the various physical constants was demonstrated for one of the fatty acids, myristic acid. 2. Surface tensions of the fatty acids were found to increase from 19.6 dynes/cm. for acetic to 27.7 dynes/cm. for stearic as the length of the carbon chain increased. Surface tensions for the ethyl esters were about 2.5 dynes/cm. lower than those for the corresponding acids, while the surface tensions for the methyl esters were about 2 dynes/cm. lower. 3. The interfacial tensions of the fatty acids and esters against water increased with increasing length of the fatty acid chain. The interfacial tension values for the acids were lower than those for the corresponding esters. For the longer chain length acids, increase in chain length had very little effect on the interfacial tension. 4. The viscosities of the fatty acids and esters increased as the number of carbon atoms in the fatty acid chain increased. Because of molecular association the acids were most viscous, and their viscosity increased most rapidly with increasing chain length. Only small and consistent differences were found in the viscosities of corresponding methyl and ethyl esters. 5. The densities of the fatty acids and esters decreased with increasing chain length, the decrease being most marked for the fatty acids and least marked for the ethyl esters. No decrease in density of the ethyl ester series was detectable beyond the butyrate. 6. The refractive indices of the fatty acids and esters increased rapidly with increasing chain length. The refractive indices of the acids were greater than those for the corresponding esters, and at the longer chain lengths the refractive indices for corresponding methyl and ethyl esters were almost identical.

The fatty acid content of meat and poultry before and after cooking

Abstract: Fatty acids distribution of various cuts of pork, lamb, beef, turkey, and chicken before and after cooking were analyzed by the spectrophotometric method. Results indicate that only a small amount of the polyunsaturated fatty acids was lost with ordinary methods of cooking. The reliability of these apparent fatty acid values after cooking is discussed. A table of fatty acid composition of these meats as eaten is also presented for dietary purposes.

The effect of mole ratio distribution on the physical properties of a polyoxyethylated alkylphenol

Abstract: It has been shown repeatedly (1, 2, 3) that for polyoxyethylated nonionic surfactants a certain hydrophobe-hydrophile balance (i.e., average mole ratio of ethylene oxide to hydrophobic material) is necessary to obtain maximum wetting, optimum detergency, etc. A study has been conducted to determine the effect of mole ratio distribution of ethylene oxide on the physical properties of a polyoxyethylated nonylphenol. This was accomplished by molecularly distilling two nonionics: a nonylphenol plus 6.0 moles of ethylene oxide and a nonylphenol plus 9.5 moles of ethylene oxide. The following conclusions have been reached concerning the effect of mole-ratio distribution on the physical properties of these surfactants. 1. The mole ratio distribution of ethylene oxide in a polyoxyethylated nonylphenol follows the Poisson formula and curve in a manner analogous to the polyoxyethylene glycols (Fig. 1). 2. The hydrophobe-hydrophile balance of the undistilled surfactant may be altered by molecular distillation. This is accomplished by narrowing the range of molecular species. 3. Wetting which is superior to the undistilled material may be effected by narrowing the distribution of molecular species (Figure 3). 4. Fractions from the distilled surfactant showed slight improvement in initial foam volume at certain mole ratios of ethylene oxide to base material over the undistilled material (Figure 6). No change in foam stability was noted. 5. Although there is an optimum ratio of ethylene oxide to the hydrophobic base at which maximum cotton or wool detergency is obtained, cotton and wool detergency are relatively unaffected by mole ratio distribution (Figure 7). 6. Surface and interfacial tension are also comparatively unaffected by mole ratio distribution change. 7. Emulsifying properties of these materials are adversely affected by narrowing the mole ratio distribution.

Industrial fat splitting

Abstract: The reaction of fat splitting, whatever the process employed, obeys the following general rules: a) The greater the proportion of free fatty acids in the fat to be hydrolyzed, the shorter will be the induction period. b) The higher the reaction temperature and the more advanced the process, the less necessary the stirring. c) The rate of hydrolysis is augmented by the raising of temperature and by the use of catalysts, proportionally to its quantity. The most active catalysts are those which most increase the solubility of water in the oil phase and which at the same time most activate that water, raising its degree of dissociation. d) The degree of hydrolysis at equilibrium, whatever the fat to be split, depends exclusively on the glycerol concentration of the sweet waters.

Influence of alkali concentration and other factors on the conjugation of natural polyunsaturated acids as determined by ultraviolet absorption measurements

Abstract: Optimum conditions for production of maximum conjugation of methyl arachidonate were determined. These comprise heating the sample in 21% KOH glycol for 15 minutes at 180°C. The optimum conditions of isomerization have also been applied to methyl linoleate, methyl linolenate, methyl eicosapentaenoate, and docosapentaenoate prepared by physical methods. These conditions greatly increased the sensitivity of the spectrophotometric method for all the polyun-saturated acids except linoleic, for which the sensitivity was unchanged. Analyses of a series of fats and oils isomerized under optimum conditions and also under standard conditions were in good agreement. Constants are given for use when pentaene acids are present as well as for acids of less unsaturation. Spectroscopic evidence strongly indicates than pentaene acids are present in lard.

Volatile cleavage products of autoxidized soybean oil

Abstract: Volatile odor principles of reverted soybean oil collected at very low temperature have been fractionated into rancidity and reversion components by adsorption on silica gel. These principles apparently contain aldehyde groups since they can no longer be detected organoleptically after the addition of aldehyde reagents. Isolations of individual aldehydes within the rancid and reverted fractions were made by forming the 2,4-dinitrophenylhydrazones and chromatographically separating these colored derivatives. Identifications were based upon melting points, ultimate analyses, and adsorption data. The following aldehydes were identified: acetaldehyde, propionaldehyde, α-pentenal, and hexanal. There is strong evidence that crotonaldehyde is also present although not completely resolved from propionaldehyde as dinitrophenylhydrazones.

A comparative evaluation of several antioxidants in edible fats

Abstract: Thirteen compounds have been intercompared with respect to their antioxidant activity in concentrations of 0.01, 0.05, and 0.10% in edible cottonseed oil, the same oil hydrogenated to shortening consistency, and in lard which is essentially free of naturally occurring antioxidants. None of the compounds exhibited significant antioxidant activity in the cottonseed oils, when use in a concentration of 0.01%, but they were effective in stabilizing lard under these conditions. Propyl gallate was the most effective of the compounds tested for the vegetable fats.

Application of urea complexes in the purification of fatty acids, esters, and alcohols. II. Oleic acid and methyl oleate from olive oil

Abstract: Oleic acid and methyl oleate of high purity (97–99%) and substantially free (0.2% or less) of polyunsaturated contaminants have been isolated in 60–70% yield from the fatty acids or methyl esters of olive oil by procedures which require only one precipitation of urea complexes (single dose of urea technique) one low-temperature crystallization, and one fractional distillation. The best yields of the highest purity acids are obtained when saturates are removed by fractional crystallization prior to a final distillation. The urea complex separation technique can be applied directly to olive oil methanolysis reaction mixtures without prior isolation of the mixed methyl esters.

Application of urea complexes in the purification of fatty acids, esters, and alcohols. I. Oleic acid from inedible animal fats

Abstract: Urea complex formation has been employed in the preparation of purified oleic acid (oleic acid content, 80–95%) from various grades of inedible animal fats and red oils. Since the urea complex of oleic acid forms in good yield at room temperature, low temperatures are not required in the isolation procedure. Yields of oleic acid are equal to or lower than those obtained by conventional low-temperature crystallization procedures, but the preparation of a polyunsaturate-free oleic acid is apparently not possible by urea complex formation alone. The separation of polyunsaturated acids from oleic acid by urea complex formation is more convenient than but not as efficient as by solvent crystallization, but separation of saturated acids from unsaturated acids is less convenient. Advantages and disadvantages in using urea in the preparation of purified oleic acid are briefly discussed.

Volatile cleavage products of autoxidized methyl linolenate

Abstract: Volatile cleavage products of autoxidizing methyl linolenate have chromatographically separated and the aldehydes have been isolated as 2,4-dinitrophenylhydrazones. Acetaldehyde, propionaldehyde, and α-pentenal have been identified. A six-carbon atom dialdehyde has been isolated as its hydrazone and is postulated to be hexene-3-dial-1,6.

Trans-octadecenoic acid content of beef fat. Isolation of elaidic acid from oleo oil.

Abstract: Infrared spectrophotometric examination of three samples of freshly-rendered edible beef fat, and of edible oleo oil and oleo stearine obtained from one of them, has revealed the presence of substantial quantities (5 to 10%) of trans materials believed to the mainly, if not exclusively, monounsaturated. It has been concluded that the trans components are neither minor nor adventitious constituents but important naturally-occurring components which may contribute to any unique properties which beef fat may have.

Polymerization of drying oils. VI. Catalytic polymerization of fatty acids and esters with boron trifluoride and hydrogen fluoride

Abstract: At relatively low temperatures boron trifluoride and hydrogen fluoride gave high yields of polymers from soybean fatty acids and methyl esters. The use of 2% boron trifluoride as catalyst at 150° to 200° resulted in the polymerization of 50–60% of the methyl esters within one hour. The viscous polymeric fraction usually had a dark color, a high acid number, and a low ratio of dimer to higher polymer. The boron trifluoride-ether complexes were equally effective catalysts and more convenient to handle. Use of the aliphatic ether complexes resulted in products having lighter colors. It was necessary to use large amounts of hydrogen fluoride to produce comparable yields at less than 100°, but 70% yields of polymers having light colors and low acid numbers were obtained.

Determination of the total unsaturation of tung oil by catalytic hydrogenation

Abstract: The use of catalytic hydrogenation as a quantitative method for the measurement of total unsaturation in tung oil and related products containing conjugated unsaturation, has been investigated.

Synthetic detergents from animal fats. Disodium alpha-sulfopalmitate and sodium oleyl sulfate

Abstract: Disodium α-sulfopalmitate and homologous compounds were prepared by sulfonation of the fat acid with liquid sulfur trioxide. Sodium oleyl sulfate was prepared in an estimated 95% purity by sulfation of oleyl alcohol with pyridine-sulfur trioxide. The solubility, surface tension, wetting, foaming, and detergent properties of these and related compounds were measured.

Carbohydrate constituents of soybean “lecithin”

Abstract: The carbohydrates present in commercial soybean lecithin consist of two types: free sugars which can be removed by extraction with 55% alcohol, and bound sugars which remain with the phosphatides. The free sugars consist mainly of sucrose and stachyose with a smaller amount of raffinose. Upon extraction of phosphatides with absolute alcohol, the sucrose is found mainly in the absolute alcohol-soluble fraction, the stachyose in the insoluble fraction, and the raffinose in both fractions.

Modification of vegetable oils. XII. Plasticity of some aceto derivatives of monostearin

Abstract: 1. Acetostearins were prepared by reacting various proportions of acetic anhydride with a monostearin of 99.2% purity, a commercially available monostearin containing 91.5% monoglycerides, and a technical grade monostearin containing 61% monoglycerides. The last mentioned product was prepared from a completely hydrogenated cottonseed oil. After the removal of unreacted acetic anhydride and acetic acid from the reaction products, the flexibility and melting characteristics were determined. 2. All of the acetostearins tested were non-greasy solids at room temperature yet were highly flexible. At a temperature of 22°C. most of them could be stretched more than 800% under the test conditions. Bending tests revealed that some of the products possessed good flexibility even at 4°C. 3. The melting characteristics of the products were dependent on the purity of the monostearin used and the degree of acetylation. Some products melted completely below body temperature (37°C.), and others melted at temperatures up to 60°C. The temperature interval over which melting occurred was usually very short (1–3°); however products made from technical grade monostearin melted over a temperature range of 10–20°C.

Protein denaturation in soybean meal during processing

Abstract: The effects of soybean oil solvent extraction on the denaturation of the protein as measured by changes of dispersibility of the nitrogen in water has been studied. The results for five commercial plants were compared with denaturation changes produced by steam treatment of laboratory prepared flakes. The results show that by use of proper conditions and equipment, flakes can be produced with a minimum of denaturation or, when desired, denaturation can be controlled within practical limits.

Dilatometric studies of pure triglycerides and mixtures

Abstract: The melting dilations and the coefficients of expansion of the solid and liquid states have been reported for five symmetrical mixed triglycerides and three simple triglyceride . The melting dilations were found to decrease with increasing proportions of oleic acid in the triglyceride molecule. In some simple mixtures the melting dilations of the several phases were found to occur discretely, but in the more complex systems there was an extension and overlapping of the melting ranges. In the mixtures of triolein with more saturated triglycerides, the melting point of triolein was found to be generally unaffected, but the melting points of the more saturated glycerides were lowered by the presence of triolein. Calculations of the solid-to-liquid ratios from dilatometric data were found to be impossible in the more complex mixtures due to wide variations in the melting dilations of the several phases and to the overlapping of their melting ranges. Approximate calculations of solid-to-liquid ratios in simple systems in which melting dilations occur discretely can be accomplished if the melting dilations of the individual triglycerides are known.

Fatty acid amides. IV. Reaction of fats with ammonia and amines

Abstract: Conditions have been worked out for the quantitative conversion of oleo oil, olive oil, castor oil, and tobacco seed oil to amides and glycerol by reaction with liquid ammonia under pressure. Similarly methyl oleate has been converted to oleamide in excellent yield. The reaction of aqueous ammonia with methyl oleate, however, gives a maximum yield of isolated oleamide of only 50%, apparently because of competition between hydrolytic and ammonolytic reactions.

Surfactants and detergents from sulfated N‐alkyl‐gluconamides

Abstract: A number of N-alkyl-d-gluconamides and a rosin substitutedd-gluconamide were prepared in good yield by reacting long chain fatty amines and rosin amine withd-glucono-delta-lactone. Reaction of these compounds with chlorosulfonic acid yielded sulfates of various degrees of substitution whose sodium salts exhibited marked surface active properties. Soil-removal tests with cotton fabric showed several of these products to be effective detergents in hard water.