Component fatty acids and composition of some oils and fats

Nineteen different samples of oils and fats have been examined for their component acids and composition by gas-liquid chromatography. Under programmed-temperature operations, the temperatures at which different components start to elute bear a straight-line relationship with their respective carbon numbers. Chromatograms, under programmed-temperature conditions, of methyl esters from such oils as coconut, groundnut, mustard, etc., are used for identifying the components of an unknown oil by comparing its chromatogram taken under nearly identical conditions. For confirmatory identifications, such plots as logarithm of retention times versus carbon numbers for saturated acids (14:0 to 24:0), monoenoic acids (14:1 to 24:1), and dienoic acids (18:2 to 24:2), under isothermal conditions, have also been used. Some new fatty acids, noted for the first time in traditional oils, are 15:0 in cottonseed oil, 20:1 in sesame oil, 22:0 in soybean oil, and 24:2 in mustard oil. Odd-carbon chain acids from 11∶0 to 23:0 have been observed in such vegetable oils as peanut germ, rice bran, andMesua ferrea. Fatty acid composition by GLC for new samples like peanut lecithin, peanut germ oil,Myristica attenuata, Myristica kanarica, Myristica magnifica, Mesua ferrea, Vateria indica, Schleichera trijuga, and shark-liver stearine are presented. Industrial utilization of these new oils and fats is discussed.     

Quantitation and occurrence of hydroxy fatty acids in fats and oils

A relatively simple method is detailed for the routine quantitation and isolation of hydroxy fatty acids (HFA) in the glycerides of lipids. The lipid in cyclohexane is transmethylated in a two-phase, 3.5 min procedure, and the hydroxyl compounds in the methyl ester fraction are derivatized with pyruvic acid chloride 2,6-dinitrophenyl-hydrazone in the presence of triethylenediamine. The derivatives are fractionated on alumina, and the HFA fraction is evaluated spectrophotometrically. A large variety of animal, plant and marine lipids contain HFA in concentrations ranging from <10 to >1000 μmoles/g lipid. The derivatives lend themselves admirably to purification techniques. A procedure for regenerating the parent HFA from the derivative is described.     

Near infrared spectral patterns of fatty acid analysis from fats and oils

A near infrared (NIR) spectral pattern of oil contains information about fatty acid composition, because NIR absorption bands around 1600–1800 nm and 2100–2200 nm are due to the straight carbon chain andcis double bonds, respectively. This study was undertaken to build a foundation for the rapid determination of the fatty acid composition in oil by an NIR method. First, NIR spectra of pure triglycerides were measured and characterized. Fatty acid compositions could be estimated roughly by comparing the spectra of fats and oils (butter fat, pig milk fat, soybean oil and palm oil) with those of pure triglycerides. Secondly, the NIR spectra of these fats and oils were reconstructed by summation of the triglyceride spectra, which are multiplied by factors corresponding to the fatty acid composition of the sample determined by gas chromatography. The calculated spectra agree with the originals, especially for that of soybean oil. However, in order to reconstruct spectra precisely, it may be necessary to reevaluate the loading weight of each triglyceride, which was equal in this study. Part of this study was presented at the 3rd International Conference on Near Infrared Spectroscopy on June 28, 1990, Brussels, Belgium.     

Reduction of glyceride oils to fatty alcohols with sodium borohydride-t-butanol-methanol

Various glyceride oils were reduced to fatty alcohols by refluxing them with sodium borohydride in a mixture oft-butanol and methanol. Chemical characteristics and infrared spectral analyses showed the products to consist mainly of alcohols and the unreduced oils. Olefinic unsaturation was not affected. Castor, coconut and mustard oils yielded 89, 84 and 60% alcohols, respectively, and cottonseed, safflower, linseed, soybean andHydnocarpus wightiana seed oils yielded 72–78% alcohols.     

Winterization of oils and fats

The process of winterization consists of fractional crystallization of oils and fats followed by the separation of solids to make high quality salad oils. To design a winterization process, the rate of cooling of oil, the temperature of crystallization and the mobility of triglyceride molecules in the oil mass are crucial. These variables play a significant role both in separating the solid fats as distinct crystals and facilitating their filtration from the oil. Thus, the main emphasis in this paper is on the effect of the above variables on the performance of the winterization process. Presented at the AOCS short course held April 21–23 1980, Lake Kiamesha, NY.