C. R. Scholfield

Composition of Soybean Lecithin

Commercial soybean lecithin is a complex mixture containing ca. 65–75% phospholipids together with triglycerides and smaller amounts of other substances. The major phospholipids include phosphatidylcholine, phosphatidylethanolamine and inositol-containing phosphatides. Other substances reported include carbohydrates, pigments, sterols and sterol glycosides. This paper reviews the nature of the compounds found in soybean lecithin and our present knowledge of its composition.

cis-trans isomerization of unsaturated fatty acids withp-toluenesulfinic acid

Elaidination of unsaturated fatty acids usingp-toluenesulfinic acid yielded 77–80% totaltrans unsaturation in the products. Results from reactions with monoene, diene, and triene isomers indicated that only geometric isomerization takes place. Each double bond isomerized randomly and independently in the polyunsaturated fatty acids. Reactions proceeded quickly, and the method proved convenient and reliable.

Components of “soybean lecithin”

SummaryThe acetone-insoluble material from soybean “lecithin” has been fractionated by submitting alcohol-soluble and alcohol-insoluble portions to countercurrent distribution between hexane and methanol. The alcohol-soluble portion was found to contain lecithin, cephalin, and sugars or glycosides; the alcohol-insoluble portion was separated into two major inositol-containing phosphatides and sugars or glycosides. While the commonly accepted value of 30–35% for lecithin in the phosphatides was confirmed, it appears that the accepted value of 65% of cephalin needs revision. The approximate composition for one sample of soybean phosphatides is estimated to be 29% lecithin, 31% cephalin, and 40% inositol-phosphatides.

Glyceride structure of vegetable oils by countercurrent distribution. III. Safflower oil

SummarySafflower oil was fractionated in a 200-tube countercurrent distribution apparatus, and the oil was also fractionated after interesterification with C14-labelled palmitic acid. The glyceride composition of the interesterified oil was similar to that of the natural oil. The glycerides were separated on the basis of both unsaturation and chain length of the constituent fatty acids, and the palmitoglycerides had only slightly higher partition coefficients than the oleoglycerides. The amounts of trilinolein, oleodilinolein, and palmitodilinolein found were similar to those calculated for a random distribution. Distribution of a mixture of safflower oil and olive oil showed that no mixing or randomization of triglycerides occurred during countercurrent distribution. It is concluded that fatty acids in safflower triglycerides are distributed in an essentially random pattern.

Silver nitrate-high performance liquid chromatography of fatty methyl esters

Long chain fatty methyl esters have been separated by high performance liquid chromatography on the basis of number, position, and geometric configuration of double bonds with a silver nitrate-silicic acid column and benzene solvent. Saturated esters are eluted first, followed by methyl elaidate and then methyl oleate. Geometric isomers of methyl 9,12-octadecadienoate and of methyl 9,15-octadecadienoate are also well separated. Methyl linolenate is retained strongly on the column and its elution has not been observed, but thetrans, trans, trans andtrans, cis, trans isomers are separated.

Glyceride structure of vegetable oils by countercurrent distribution. V. Comparison of natural, interesterified, and synthetic cocoa butter

The glyceride structure of cocoa butter is of considerable practical importance and of particular theoretical interest Countereurrent distribution, gas chromatography, and isotopic dilution methods are employed in its study. The observed fractionation of glycerides is acounted for by assuming that palmitie and stearic acids are randomly esterified on the 1 and 3 positions of glycerol and that oleic is on the 2 position, as demonstrated by other workers. Complete randomization of the specifie structure of cocoa butter through the application of interesterification eatalysts greatly alters its physical A glyceride synthesized according to the “1,3 random palmitostearo-2-olein” concept has properties similar to natural cocoa butter.

Gas chromatographic equivalent chain lengths of fatty acid methyl esters on a silar 10C glass capillary column

Gas chromatographic equivalent chain lengths have been determined for a number of fatty acid methyl ester isomers on a Silar 10C glass capillary column at 170 C. The results are comparable with others published for polycyanopropylsiloxane columns.

Double bond analysis of dienoic fatty acids in mixtures

Mixtures of dienoic fatty acids such as occur in edible hydrogenated fat products cannot be analyzed by current methodology. A method of ozonization, reduction to alcohol fragments by sodium borohydride, gas chromatographic analysis for alcohol, alcohol ester, and internal dialcohol fragments, and computer resolution of a matrix of linear simultaneous equations, is described that gives the analysis of the diene isomers.

Argentation high performance liquid chromatography of methyl esters

The technique of argentation chromatography with silver ion on a macroreticular exchange resin has been applied to high performance liquid chromatography (HPLC) to separate fatty methyl esters and their isomers. Elution of methyl linolenate from the column and more rapid separation of dienes are made possible by programming column temperature from 25 to 70 C. Samples from ca. 0.025 μ to 8 μl can be analyzed on a 2-mm id x 61-cm column. Two 7-mm id x 61-cm columns in series have been used to separate 100-μl samples into fractions for further analysis by capillary gas chromatography. Various forms of argentation chromatography have been widely used for analysis and for separation of compounds from oils and fats including hydrogenated soybean oil. This paper describes the application of argentation procedures to modern HPLC to obtain faster, more efficient separations. It also describes the application of temperature programming to give more rapid separations and to extend our previous method to include methyl linolenate and its isomers.

New developments in silver resin chromatography ofcis andtrans fatty methyl esters

Chromatographic separations of geometric isomers of methyl octadecenoates and octadecadienoates on a silver-treated macroreticular resin are much improved with newer resins of greater surface area and ground to a smaller particle size.cis,cis-Dienes can be recovered in practical elution volumes. With methanol as solvent small molecules including even radioactive methanol are retarded on the column relative to methyl esters of saturated acids.