J. L. White

Chromatographically homogeneous lecithin from egg phospholipids

Chromatographically homogeneous egg lecithin, as determined by TLC on Silica Gel G, has been isolated from crude egg phosphatides by column chromatography on alumina through modification of existing, lengthy methods. The modified method involved application of crude egg phosphatides to a column of alumina in the proportion of 1 g phosphatide/25 g alumina, and elution of the lecithin fraction with the 2-component solvent system chloroform:methanol, 9:1 by vol. This method of purification separated lecithin from other choline and non-choline components of crude phosphatides, avoided overloading of the alumina column, and made unnecessary the need for a second chromatographic fractionation of partially purified lecithin on silicic acid, which is needed in existing methods of purification of lecithin.The use of fresh yolks permitted easier removal of pigment from the final product than was possible with commercially dried yolks.Phosphatides extracted from dried yolks were much more highly colored than were the phosphatides extracted from fresh yolks and the color presisted through chromatography on alumina.The fatty acid/phosphorus molar ratio of the purified lecithin was 2.00, which is the theoretical FA/P molar ratio of phosphatidylcholine; other materials with this ratio were not present.

Fat emulsions. Effect of polyoxyethylene and alkyl content of emulsifiers on stability to sterilization

SummaryWhen a given system of emulsifiers of known compositions and molecular weights was employed, it was found that in order for fat emulsions of 15% oil content to be stable to the heat required for sterilization, the emulsifiers must meet definite requirements. Minimum weight percentage of total lipophilic groups should be 0.29%; minimum weight percentage of total hydrophilic groups should be 0.57%; the polyoxyethylene groups of emulsifiers containing such groups should account for at least 70% of the mole weight of these emulsifiers; the lipophilic/hydrophilic ratio should be about 0.5. The minimum content of lipophilic and hydrophilic groups was found to be an additive total of these groups as provided by the complete emulsifying system whether composed of individual or multiple emulsifying agents and whether of similar or dissimilar functional groups.With the emulsifiers used, an acyl group greater in length than 12 carbon atoms was found to be necessary to prepare cottonseed oil emulsions which were stable to heat.Resistance of emulsions to breakage by mechanical shock was imparted by a rather large amount of lipophilic groups, so that the lipophilic/hydrophilic ratio was 1 or over.

Titration of cyclopropene esters with hydrogen bromide

Esters of the naturally occurring cyclopropene acids have heretofore been determined by titration with hydrogen bromide in glacial acetic acid. However, highly purified cyclopropenes had an apparent purity of only 83–86% by this method. The catalyzed addition of acetic acid during the titration has been shown to occur. Substituting toluene for the acetic acid not only gives the correct cyclopropene content, but also sharpens the end point of the titration. The new titration is performed at 70–75 C and 1,3-diphenylguanidine, which is soluble in toluene, should be used as a primary standard. The indicator solution is 0.03% crystal violet in butyric acid. Mono- and diglycerides and oxidized fatty compounds must be removed before titration. Oxirane oxygen can be determined by the new procedure, probably with an accuracy greater than that possible with hydrogen bromide in glacial acetic acid.

Surface activity of glycerol glycoside palmitates

A glycoside ester product was prepared by the transglycosylation of starch and glycerol, which yielded a mixture of 2,3-dihydroxypropyl-α-D-glucopyranoside and other glycerol glycosides, followed by interesterification of the crude glycerol glycosides with a mixture of mono-, di- and tripalmitin. The purified reaction product, consisting of ca. 77% glycerol glycoside palmitates, 14% palmitins and 9% free palmitic acid, was found to be extremely effective in lowering the interfacial tension between cottonseed oil and water—a 0.04% concentration in the oil phase lowering the interfacial tension to 1.3 dynes/cm.

Hydrogenation of cyclopropenoid fatty acids occurring in cottonseed oil

The hydrogenation of cyclopropenoid acids and their relative reactivities during hydrogenation as compared to linoleic and oleic acids were examined. Pure methyl sterculate and purifiedSterculia foetida oil and its methyl esters, which have a cyclopropene content more than 60 times that of cottonseed oil, were used for the hydrogenation experiments. Nickel, palladium and platinum catalysts were used. The effect of temperature and type of catalyst were demonstrated in a series of hydrogenation experiments of safflower andS. foetida oil mixtures, and methyl oleate and methyl dihydrosterculate mixtures. Partial hydrogenation of methyl sterculate formed as many as twenty compounds in addition to the cyclopropenoid derivatives. Most of these compounds were monounsaturated. The cyclopropene group hydrogenated very readily compared to the 9,12-diene system in linoleate. The cyclopropane group obtained by hydrogenating the cyclopropenoid acids group was quite resistant to further attack by hydrogen and nickel catalyst had little effect. With palladium catalyst, a temperature of 180 C was necessary for the reaction to go to completion. Platinum in acetic acid was a good system for hydrogenolysis of the cyclopropane group at 80 C.

An emulsifier system for experimental intravenous fat emulsions

An emulsifying system for a fat emulsion which has been very satisfactory for intravenous administration to dogs has been developed. The emulsion contained cottonseed oil (15%), polyethylene glycol monopalmitate (1.2%), tartaric acid ester of monoglycerides (0.3%), and polyoxyethylene-polyoxypropylene (0.3%), in isotonic dextrose solution. The polyethylene glycol monopalmitate was isolated from laboratory and commercial esterification reaction mixtures of monoester, diester, and nonreacted polyethylene glycol. Washing with NaCl solution removed nonreacted glycol, and fractionation in acetone separated the mono- and di-esters, the diester separating as a solid. Analytical methods were applied to characterize all fractions, and to determine the reproducibility of composition of successive batches. The monopalmitates from both laboratory and commercial preparations were similar in properties. The tartaric ester of monoglycerides was washed with NaCl solution and fractionated in acetone. The liquid portion was recovered and used for emulsification. Emulsions prepared with the fractionated emulsifiers appear to give satisfactory physiologic results when infused in dogs.

Browning in phosphatide-containing fat emulsions.

Summary This investigation gives experimental evidence that at autoclaving temperature (121°C) a type of browning occurs which involves reaction of dextrose with lecithins as well as with amino-groups of cephalins. Therefore, use of pure lecithin as an emulsifier in an oil emulsion containing dextrose in the water phase would not eliminate formation of the brown material. The complex browning reaction is responsible for formation of a colloidal material found in phosphatide-containing fat emulsions prepared for intravenous alimentation, and might be a possible explanation of certain adverse physiological results occasionally experienced with the use of these emulsions.

Hydrogen bromide titration for soaps in fat products

Since none of the existing methods for determining soaps in fat products have been found to be entirely satisfactory, a method has been devised for the determination of alkali metal soaps by direct titration with Durbetaki reagent (hydrogen bromide dissolved in glacial acetic acid). When the titration was conducted at room temperature in acetic acid-benzene solution with crystal violet as indicator, soaps of potassium, sodium and lithium could be determined accurately in anhydrous oils, monoglycerides, and sucrose esters. The presence of alcohols, glycerol and sucrose did not interfere in the direct titration. However, oxidized oils, epoxides, and cyclopropenoid acids, which are known to consume hydrogen bromide, did interfere. Products containing the interfering substances could be analyzed by a modified procedure in which the alkali metal cations were extracted from a mixture of amyl acetate andn-butanol (1:3) into an aqueous solution of acetic acid, and titrated as the acetates.

Crude glycerol glucoside esters of cottonseed oil: Preliminary cost analysis

Glycerol glucoside esters prepared by transglycosylation of starch and glycerol, followed by interesterification with esters of cottonseed oil fatty acids, are well suited for use in the steadily growing food emulsifier market. They offer formulators and processors a wide range of compositions and physical properties for achieving more effective emulsification without increase in cost. Process flowsheets, capital costs, manufacturing costs, and general expenses are given for the production of 5.7 million pounds and 17.2 million pounds of crude glycerol glucoside esters annually in hypothetical 4-ton batch and 12-ton batch grass-roots plants, respectively. A material balance and preliminary plant layout for the 12-ton batch plant are also provided. The cost of crude esters ranges from 37.4 cents to 43.7 cents/lb, indicating that the crude esters would be competitive with many commercially available food emulsifiers. The process can be carried out in conventional batch process equipment without production of polluting byproducts. Fixed capital investment for a new 12-ton batch plant would be

Preparation of fatty acid esters of polyol glucosides

2.5 million, and for a new 4-ton plant,