Studies on the fatty acid composition of crayfish lipids

The fatty acid composition of carcass and exoskeleton lipids was determined for the freshwater crayfishOrconectes rusticus. Lipid fractions were isolated by column and thin-layer chromatography. Fatty acid methyl esters and alcohol acetates were then prepared and analyzed by gas-liquid chromatography. Peak identities were established from retention time data for methyl esters, hydrogenated methyl esters, and saturated, monoene, diene, and polyene methyl esters separated as acetoxy-mercuri-methoxy derivatives. Minor component acids were estimated from their relative compositions in these fractions. Presented at the symposium honoring J. B. Brown, AOCS meeting in Chicago, 1964.     

Phospholipid fatty acid composition and stereospecific distribution of soybeans with a wide range of fatty acid composition

Phospholipid (PL) fatty acid composition and stereospecific distribution of 25 genetically modified soybean lines with a wide range of compositions were determined by gas chromatography and phospholipase A₂ hydrolysis. Pl contained an average of 55.3% phosphatidylcholine, 26.3% phosphatidylethanolamine, and 18.4% phosphatidylinositol. PL class proportions were affected by changes in overall fatty acid composition. PL fatty acid composition changed with oil fatty acid modification, especially for palmitate, stearate, and linolenate. Stereospecific analysis showed that saturated fatty acids were primarily located at the sn-1 position of all PL, and changes of the saturates in PL were largely reflected on this position. Oleate was distributed relatively equally between the sn-1 and sn-2 positions. Linoleate was much more concentrated on sn-2 than on sn-1 position for all PL. Linolenate was distributed relatively equally at low concentration but preferred sn-2 position at high concentration.     

Altered fatty acid desaturation and microsomal fatty acid composition in the streptozotocin diabetic rat

Streptozotocin diabetes in the rat diminishes the synthesis of both monounsaturated and polyunsaturated fatty acids. Rat liver microsomal fatty acid composition and fatty acid desaturation were studied in the streptozotocin diabetic rat. The major alterations in fatty acid composition found in the diabetic rat were decreased proportions of palmitoleic, oleic and arachidonic acids and an increased proportion of linoleic and docosahexaeneoic acids. These findings, other than the increased docosahexaeneoic acid, probably result from the diminished liver microscomal δ9 and δ6 desaturase activities found in these animals. These changes are not due to the diminished weight gain of the diabetic animals since restricting food intake of control animals to achieve a similar weight gain failed to reproduce either the changes in fatty acid composition or the decrease in fatty acid desaturation. The increased food intake of the diabetic animal may contribute to the altered proportions of linleic and arachidonic acids since limiting food intake in diabetic animals to that of normal controls diminished the magnitude of these changes. Insulin therapy for 2 days not only reverses and overcorrects the diminished desaturase activities, but likewise reverses and overcorrects the altered fatty acid composition, with the exception of the diminished arachidonic aicd levels which are further decreased following insulin therapy. These findings strongly suggest that most of the changes in fatty acid composition in the diabetic rat are indeed caused by the diminished fatty acid desaturase activities.     

Improving the fatty acid composition of soybean oil

Efforts to improve the composition of soybean oil by breeding the beans for low linolenic acid in the oil have continued since 1968. This paper reports recent work using hybrid crosses and induced mutations. No lines are yet available that contain oil having less than 3% linolenic acid. Journal Paper No. J-11466 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2475.     

Effects of essential fatty acid deficiency on prostaglandin synthesis and fatty acid composition in rat renal medulla

Studies are reported on the capacity of isolated rat renal papilla (inner medulla) to synthesize and release prostaglandin (PG) E from endogenous and exogenous precursor(s) during development of an essential fatty acid (EFA) deficiency in the rat. Weanling (21-day-old) male Sprague-Dawley rats were fed a fat-free diet supplemented with either 5% hydrogenated coconut oil (HCO) or 5% safflower oil (SO). At approximately 3, 6 and 7 weeks (6, 9 and 10 weeks of age), groups of animals fed each diet were killed for studies of PGE synthesis in the renal papillae. Differences in the fatty acid composition of the papillae lipids of the animals of each group were also determined. The in vitro production of PGE from endogenous precursor(s) was significantly reduced in the papillae from the 6-week-old rats fed the HCO diet compared to the control (SO) rats, and appeared to be near maximally depressed in the 10-week-old animals compared to that of animals fed an EFA deficient diet for over a year in an accessory experiment. Analyses of the fatty acids of the papillae lipids of the HCO groups showed that the levels of 18∶2 and 20∶4 were markedly reduced, and those of 16∶1, 18∶1 and 20∶3 were elevated compared to the controls even in the 6-week-old animals, typical of an EFA deficiency. The papillae lipids of the animals fed the HCO diet were also depleted of their stores of 22∶4ω6. A fatty acid believed to be derived by chain elongation of 20∶3ω9, 22∶3, was found in large concentrations in the papillae triglycerides of the EFA deficient rats. Incubations of exogenous arachidonic acid (20∶4) in homogenates and tissue slices of the papillae of the HCO dietary groups showed that the PG synthetase was not impaired by an EFA deficiency. The rate of PGE synthesis in the papillae of the EFA deficient animals was generally enhanced when exogenous 20∶4 was added, indicating that the concentration of available precursor(s) is a primary factor in the control of PGE synthesis in the papilla of the rat.     

Dietary fat and the fatty acid composition of tissue lipids

Some characteristics of the fatty acid composition of animal tissue lipids are described and the origins of tissue fatty acids are discussed briefly. The effect of dietary fat on composition of tissue lipids is discussed. Types of dietary fatty acids for which experimental work is described include polyunsaturated fatty acids, short-chain fatty acids, fatty acids with chain length greater than C₁₈,trans unsaturated fatty acids, fatty acids with conjugated double bonds, acetylenic fatty acids, branched-chain fatty acids and oxygenated fatty acids. The individuality of fatty acids is discussed in relation to their roles as components of tissue lipids.     

The fatty acid composition of clothes soil

Summary Organic soil that had gradually accumulated on cotton garments and was unremovable by normal washing procedures was analyzed for free and combined fatty acids by gas-liquid chromatography. The fatty acid composition of this material was similar to sebum and hair fat and was remarkably uniform although from several different sources and geographical locations. The predominant fatty acids were C₁₅, C₁₆, and C₁₈ straight-chain acids. More than 30% of the total fatty acid was palmitic acid. The amount of oleic acid was considerably less than is reported for hair and skin fat. No linoleic acid or linolenic acid was detected. The small amount of unsaturated acids is probably the result of their oxidation to polymers and other oxidation products. The amount of free fatty acids was very small because they were converted to insoluble heavy metal soaps. Most of the combined fatty acids were present as esters,i.e., triglycerides.     

The fatty acid composition of some entomophthoraceae

Lipids extracted fromConidiobolus denaesporus Drechsl. were found to contain three branched-chain fatty acids, which together comprised about 35% of the total fatty acids of the fungus. The branchedchain acids were identified by gas-liquid chromatography, infrared and mass spectroscopy as 12-methyl tridecanoic, 12-methyl tetradecanoic, and 14-methyl pentadecanoic acids respectively. Then-saturated acids comprise C12, C13, C14, C16, and C18. Then C16,n C18, andn C20 unsaturated acids were also found. The occurrence of 15.2% of myristic acid and of 8.9% of eicosatetraenoic acid provides a further distinctive feature of the lipids ofConidiobolus denaesporus. Contribution No. 94.     

The fatty acid composition of the seeds ofGinkgo biloba

The fatty acid composition of seeds ofGinkgo biloba has been examined by a combination of capillary gas chromatography, silver ion high-performance liquid chromatography and gas chromatography/mass spectrometry. Some of the fatty acids identified are unusual in plants and were rather different from those reported earlier. These include ananteiso-methyl branched fatty acid, 14-methylhexadecanoic acid, 5,9-octadecadienoic acid, and 5,9,12-octadecatrienoic acid. Fourier-transform infrared spectroscopy confirmed that all of the double bonds were of thecis-configuration.     

Chromatographic studies on oxidative and thermal fatty acid dimers

A chromatographic study was carried out to investigate the nature of polymeric products in edible oils. Dimers from low-temp oxidation of methyl linoleate were compared with thermal dimers from high-temp polymerization of conjugated methyl linoleate. The distilled dimers were subjected to liquid-partition chromatographic separations on silicic acid columns as methyl esters, as free acids, and as methyl esters prepared by saponification and reesterification. Chromatographically isolated dimer fractions were also rechromatographed before and after each treatment. When thermal dimer esters are saponified and reesterified, chromatographic recoveries are quantitative, and the expected changes in polarity result; whereas, with oxidative dimer esters, gross changes in polarity occur. Chromatographic separations of dimer esters or their acids fractionate into distinct areas of increasing polarity. Presented at the AOCS Meeting, New Orleans, 1964. Honorable Mention, Bond Award Competition. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, USDA.     

Studies on lipid and fatty acid composition of human hepatoma tissue

Studies are reported on the composition of the lipids of human liver and hepatoma tissues from male adults. Liver tissues were obtained from individuals who died from causes other than liver disease or cancer. The hepatoma tissues were obtained from individuals shortly after they succumbed to cancer. The total lipid of each tissue was fractionated quantitatively by silicic acid column chromatography into neutral lipid, glycolipid, and phospholipid fractions. These fractions were analyzed by thin layer chromatography and converted to methyl esters for analysis of their constituent fatty acids by gas liquid chromatography. In comparison to liver tissue, the total amount of lipid in the hepatoma tissues was generally higher and more variable; the lipid of one hepatoma was ca. 92% of the dry wt of the tissue. The greater lipid content of the hepatoma tissues was due to the high percentage of neutral lipid. Except for one specimen, there was ca. the same amount of glycolipid in the hepatoma as in the liver tissues, but the composition of the glycolipid fraction of the hepatoma lipid differed considerably, particularly in the ganglioside fraction. The phospholipid fraction of hepatoma lipid was much lower than that of liver but exhibited only quantitative differences in composition. No glyceryl ether diesters and only traces of plasmalogens of phosphatidyl choline or phosphatidyl ethanolamine were detected in the liver and hepatoma lipids. The levels of monoenoic acids were higher and those of linoleic and polyunsaturated fatty acids lower in the hepatoma lipids. Positional isomers of trienoic acids not normally present in liver tissue were detected in hepatoma lipids. The abnormalities observed in lipid composition indicated interferences in the regulatory processes of lipid metabolism in human hepatoma similar to those observed in animals.     

The influence of dietary fatty acids and environmental temperature on the fatty acid composition of teleost fish

Marine and fresh water fish were depleted of tissue unsaturated fatty acids to various degrees and subsequently presented with linoleic and linolenic acids at different dietary levels, at different temperatures, with and without other dietary fat. Examination of the tissue fatty acids demonstrated that marine and fresh water fish do not differ between themselves or from other classes of animals in the following basic mechanisms of deposition and interconversions of dietary fatty acids:

1. 1)
   The fish are readily depleted of tissue polyunsaturated fatty acids.     
   
   

Density estimation for fatty acids and vegetable oils based on their fatty acid composition

The liquid density of fatty acids can be accurately estimated by the modified Rackett equation over a wide range of temperatures. The modified Rackett equation requires the critical properties and an empirical parameter,Z _RA , for each acid as the basis for computing density as a function of temperature. The liquid density of vegetable oils can be estimated by using mixture properties corresponding to the fatty acid composition and a correction for the triglyceride form. The density prediction is explicitly temperature-dependent.     

trans fatty acids. 4. Effects on fatty acid composition of colostrum and milk

trans Isometric fatty acids of partially hydrogenated fish oil (PHFO) consist oftrans 20∶1 andtrans 22∶1 in addition to thetrans isomers of 18∶1, which are abundant in hydrogenated vegetable oils, such as in partially hydrogenated soybean oil (PHSBO). The effects of dietarytrans fatty acids in PHFO and PHSBO on the fatty acid composition of milk were studied at 0 (colostrum) and 21 dayspostpartum in sows. The dietary fats were PHFO (28%trans), or PHSBO (36%trans) and lard. Sunflower seed oil (4%) was added to each diet. The fats were fed from three weeks of age throughout the lactation period of Experiment 1. In Experiment 2 PHFO or “fully” hydrogenated fish oil (HFO) (19%trans), in comparison with coconut oil (CF) (0%trans), was fed with two levels of dietary linoleic acid, 1 and 2.7% from conception throughout the lactation period. Feedingtrans-containing fats led to secretion oftrans fatty acids in the milk lipids. Levels oftrans 18∶1 andtrans 20∶1 in milk lipids, as percentages of totalcis+trans 18∶1 andcis+trans 20∶1, respectively, were about 60% of that of the dietary fats, with no significant differences between PHFO and PHSBO. The levels were similar for colostrum and milk. Feeding HFO gave relatively lesstrans 18∶1 andtrans 20∶1 fatty acids in milk lipids than did PHFO and PHSBO. Only low levels ofcis+trans 22∶1 were found in milk lipids. Feedingtrans-containing fat had no consistent effects on the level of polyenoic fatty acids but reduced the level of saturated fatty acids and increased the level ofcis+trans monoenoic fatty acids. Increasing the dietary level of linoleic acid had no effect on the secretion oftrans fatty acids but increased the level of linoleic acid in milk. The overall conclusion was that the effect of dietary fats containingtrans fatty acids on the fat content and the fatty acid composition of colostrum and milk in sows were moderate to minor.     

Analysis and fatty acid composition of tobacco seed oils

Summary THE fatty acid compositions of twelve samples of oil representing a number of different types and varieties of tobacco were determined by the thiocyanometric method. The samples were remarkably uniform in composition, containing on the average 75% linoleic, 15% oleic, and 10% saturated acids. Spectrophotometric determination of the linoleic acid content of two samples of oil gave values 3.0 and 5.4% higher than those by the thiocyanometric method. A more complete investigation of the fatty acid constituents of one sample of flue-cured tobacco seed oil was carried out by analysis of fractions obtained by distillation of the methyl esters and by low-temperature crystallization of the distilled ester fractions. The composition calculated from these analyses agreed well with that determined from analysis directly on the oil. The saturated acids consisted of palmitic and stearic acids, the proportions being about 7 and 3%, respectively, of the total fatty acids. Analysis of this sample of oil showed that it contained 0.043% of tocopherol. From its composition, tobacco seed oil would seem to be particularly suitable for the manufacture of nonyellowing alkyds or for the preparation of technical linoleic acid. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.     

Phospholipid content and fatty acid composition of human heart

Phospholipid content and fatty acid composition of human heart were determined on 36 biopsy specimens collected during open heart surgery. The main phospholipid classes, phosphatidylcholine (PC), phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), and sphingomyelin (SPH) were separated by HPLC, quantified, and converted to fatty acid methyl esters which were chromatographed on capillary GLC columns. Sex and age (mainly 40–70) of patients had no significant influence on the relative distribution of phospholipid classes and only a slight effect on fatty acid composition. Incorporation oftrans 18∶1 in phospholipid classes was low.cis andtrans octadecenoic isomers seemed to be selectively incorporated, the Δ9 and Δ11cis ortrans isomers being predominant. Human and rat data were compared, and some species differences were noticed. In human PC, palmitic acid is higher and stearic acid much lower than in rat PC. Saturated dimethyl acetals (16∶0 and 18∶0) in PC and PE were greater for humans. Incorporation of 20∶4 n−6 in human PE is higher than in rat PE.     

Tocopherol and fatty acid composition of some Indian pulses

The tocopherol and tocotrienol composition of the Indian pulses Bengal gram (Cicer arietinum L.), blackgram (Vigna mungo L.), green gram (Vigna radiata L.), and horse gram (Dolichos biflorus L.) were studied. The total tocopherol content ranged from 230 to 1567 mg/100 g fat, while the tocopherol content of the pulses as a whole ranged from 6.76 to 12.54 mg/100 g seed. Presence of such a high amount of tocopherol, both in the oil fraction of Indian pulses and in an oil fraction of a food material, is being reported for the first time. The fatty acid composition of the fat extracted from these pulses showed substantial amounts of unsaturated fatty acids (Bengal gram, 88.7%; black gram, 82.9%; green gram, 64.3%; and horse gram, 66.9%). These pulses contained 3.8 to 49.1% linolenic acid in the fat.     

Cyclopropenoid fatty acid content and fatty acid composition of crude oils from twenty-five varieties of cottonseed

The cyclopropenoid acid content of oils extracted from 22 commercial varieties and 3 botanical species of cottonseed have been determined. The malvalic acid content determined by HBr titration varied from a low of 0.56% to a high of 1.17%. Iodine values of the oils ranged from 96.8 to 111.6 No definite correlation could be established between iodine value and malvalic acid content. Equations for regression lines for the major acids have been calculated from plots of fatty acid composition vs. iodine value. The high degree or correlation suggests that for commercial oils the fatty acid composition can be estimated from the iodine value. Oils of the 3 experimental types of different species showed wide variations in fatty acid composition and represented many of the maximum and minimum values reported. So. Utiliz. Res. Dev. Div., ARS, USDA. ARS, USDA.     

Phospholipid and fatty acid composition of Bulgarian nut oils

The phospholipid and fatty acid composition of three Bulgarian nut oils were investigated. Phospholipids were separated by Folch′s method and two-directional thin-layer chromatography. Their content was determined spectrophotometrically. Phospholipids were present at levels of 0.8% in almond oil, 2.8% in hazelnut oil, and 0.9% in walnut oil. Phosphatidylcholine (18—50%), phosphatidylinositol (18—45%), and phosphatidylethanolamine (8—16%) were found to be the major components. Small amounts of phosphatidylserine, phosphatidic acids, phosphatidylglycerols, lysophosphatidylcholine, and lysophosphatidylethanolamine were also detected. The fatty acid composition of glyceride oils and of the four main phospholipids, namely phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acids was identified by capillary gas chromatography of their methyl esters. The predominant fatty acid present in almond and hazelnut oils was linoleic (83.2% and 80.8%, respectively). Oleic acid (18.7%), linoleic acid (48.5%), and linolenic acid (15.8%) were the major components in walnut oil. Higher quantities of saturated fatty acids (27.8—81.2%) were found to be in the phospholipids than in the corresponding oils (9.5—16.7%).