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A new method for the detection and estimation of long-chain epoxy acids in seed oils is described. It depends on the measurement of increased absorption at 2.795 μ in the near infrared spectrum caused by chlorohydrins produced from epoxides by treatment with anhydrous ethereal hydrogen chloride. The method is sensitive to approximately 0.2% of epoxy acid in an oil and is specific for epoxides. Hydroxy components of a sample do not interfere since the strongly associated hydroxyl band of chlorohydrins is normally clearly resolved from other OH absorption. The presence of large amounts of vicinally unsaturated hydroxy acids, however, results in large changes in absorption intensity in the 2.8 μ region on HCl treatment and in these cases epoxide concentration cannot be accurately measured but must be estimated. These reactive hydroxy acids, which lead to spurious epoxide values by the conventional methods, lose hydroxyl during the acid treatment, and measurement of the decrease in their absorption at 2.762 μ means that their concentration may be estimated concurrently with that of epoxy components. Other reactive acids, such as cyclopropenoid acids, which result in high epoxide values by the usual methods, do not interfere. Results obtained by this spectrophotometric method are compared, for some oils, with those obtained by the usual chemical methods of epoxide determination.

Chromatographic procedures for the detection and evaluation of oxygenated fatty acids are described. Emphasis has been placed on epoxy acids, but these methods promise to be of great value in studies of all classes of oxygenated acids. Paper chromatography of fatty acids and their esters has been developed for the examination of mixtures containing oxygenated derivatives. The method of adsorption chromatography on thin layers of silicic acid has been shown to be a powerful tool in studies of epoxy acids and hydroxy acids. Gas-liquid chromatography (GLC) of epoxy esters has been studied using both polar and nonpolar columns and has great utility in the detection and analysis of these compounds in mixtures. These methods have been applied to the examination of the epoxy components of six seed oils. Thin-layer and GLC proved particularly useful in this study and together demonstrated the presence of at least three distinct epoxy acids in each of these oils. Some conclusions as to the probable structures of these epoxy components are presented on the basis of their chromatographic characteristics in relation to known substances.

Supplements of purified fatty acid methyl or ethyl esters were fed at levels of 0.8% of dietary calories to each of seven groups of weanling rats for a period of 60 days. The esters were 9,12-octadecadienoate (18:2) ; 9,12,15-octadecatrienoate (18:3); 10,13-nonadecadienoate (19:2); 5,8,11,14-eicosatetraenoate (20:4); 5,8,11,14,17 - eicosapentaenoate (20:5); 4,7,10,13,16,19-docosahexaenoate (22:6); and 12:13-epoxyoctadeca-9-enoate (epoxyoleate). Rats fed a fat-free diet served as control animals. The effects of these dietary supplements on the fatty acid compositions of the nonphospholipids and phospholipids from liver microsomal and mitochondrial particles, and of unfractionated lipids from liver, testes, epididymal, and heart tissues were determined by gas–liquid chromatography.Epoxyoleate and 19:2, which are structurally related to linoleic acid, did not function as essential fatty acids as judged by the chemical and biological symptoms of fat deficiency. Dietary 20:5 and 22:6, both related to linolenate, were less active than linoleate in preventing the biological symptoms of fat deficiency, but more active in depressing the content of eicosatrienoate. Docosapentaenoic acid of the linoleate family was identified by reductive ozonolysis and shown to increase with an increase in dietary 18:2 or 20:4.

The fatty acid Composition of lipids from erythrocytes and depot fat of rats whose diet was supplemented with various levels of linoleate, arachidonate, or linolenate has been investigated. Dietary linoleate and linolenate are incorporated into the depot fat. The ratio of eicosatrienoic acid to eicosatetraenoic acid, derived from the analysis of depot fat, decreases with increasing amounts of all three dietary essential fatty acids (EFA) in the same manner as observed in organ lipids. The composition of the unsaturated fatty acids of erythrocyte lipids is altered readily by increasing amounts of dietary EFA. The concentration of 20: 3 is lowered extensively by all three EFA. The synthesis of arachidonate is inhibited by dietary linolenate and 20:5 and 22:5ω3 (double bond between third and fourth carbow from ω end) can be detected only in animals given linolenate.

Rats were fed various levels of either ethyl linoleate, ethyl arachidonate, or ethyl linolenate. Weight gain, fat-deficiency status, and fatty acid composition of the liver lipids were determined.Dietary linoleate, fed in excess of 1% of calories, maintained good growth and cured fat deficiency. Increasing amounts of dietary linoleate were stored in the liver lipids and converted into fatty acids of the linoleate family—20:4 and 22:4. The concentration of 20:3 was decreased. Dietary arachidonate cured fat deficiency three times more effectively than linoleate. Increasing amounts of dietary arachidonate were stored in liver lipids and converted to 22:5ω6. The level of 20:3 was lowered three times more effectively than when linoleate was fed. No fatty acids of the linolenate family were synthesized from linoleate or arachidonate.Dietary linolenate did not support weight gain as efficiently as did linoleate or arachidonate. Fat-deficiency symptoms could not be cured completely. Increasing amounts of dietary linolenate increased the levels of fatty acids of the linolenate family; linolenic acid was stored, and 20:5, 22:5ω3, and 22:6 were synthesized from linolenate. The level of 20:3 was lowered in the same fashion as when linoleate or arachidonate was fed. Thr level of 20:4 was decreased with increasing amounts of dietary linolenate.

Malonyl coenzyme A is synthesized by transacylating S-malonyl-N-decanoyl cysteamine with coenzyme A. A simplified procedure for the preparation of S-malonyl-N-decanoyl cysteamine, using cysteamine as starting material, is described.