Zur Tocochromanol- und Fettsäureanalytik im Fisch

Analysis of Tocochromanols and Fatty Acids in fish Tocochromanols and lipids are quantitatively extractable from homogenate of the edible part (muscle and skin) of carp with dichloromethane and methanol at room temperature. The contents of tocopherols and tocotrienols are determinable directly in the lipid extract dissolved in n-hexane by HPLC (fluorescence detection). The fatty acids of the polyenic acid rich lipids are derivated to the methyl esters. Transesterification is carried out with methanolic potassium methylate solution, followed by esterification of possibly present free fatty acids with boron trifluoride-methanol, at room temperature. The fatty acid methyl esters (C8 :0 to C22:6 ω3) are separated and quantified by capillary gas chromatography on the station ary phase FFAP.     

Strukturaufklärung cyclischer Fettsäuremethylester IV: Über das Auftreten von ω-Phenylalkancarbonsäure-methylestern in cyclisiertem Holz- und Leinöl

Structure Elucidation of Methyl Esters of Cyclic Fatty Acids IV: Occurrence of Methyl Esters of ω-Phenyl Alkanoic Acids in Cyclised Tung and Linseed Oil Methyl esters of cyclic fatty acids (CFA-Me) obtained from alkali cyclised tung and linseed oil were oxidized by performic acid. A series of fractions containing methyl esters of various aromatic fatty acids were obtained by column chromatographic separation of the oxidation products. Whereas the initial fractions consisted of methyl esters of ω-(o-alkylphenyl)alkanoic acids (AFA-Me), the later fractions were found to contain a homologous series of unsubstituted ω-phenyl alkanoic esters. The main component in cyclised tung and linseed oil is the methyl ester of 9-phenyl nonanoic acid. The formation of methyl esters of aromatic fatty acids is discussed.     

Zur gaschromatographischen Analytik trans-isomerer Fettsäuren auf gepackten Säulen (Silar 10 C,Silar 9 CP,SP 2340, OV 275) sowie auf der mit SP 2340 beschichteten Glaskapillare

Gas Chromatographic Analysis of trans-Isomeric Fatty Acids on Packed Columns (Silar 10C, Silar 9CP, SP 2340, OV 275) and in Glass Capillary Coated with SP 2340 High polar and temperature-resistant cyanopropylsiloxane phases such as Silar 9CP, Silar 10C, SP 2340 and OV 275 have a high selectivity for double bonds and make it possible, for the first time, to separate cis/trans isomeric fatty acid methyl esters on packed columns. The possibilities and limitations for identifying and separating the positional and geometric isomers of monoene, diene and triene fatty acid methyl esters on packed columns are demonstrated by numerous examples and compared with the application range of the SP 2340 glass capillary column. In addition to fatty acid methyl esters, non-derivated fatty acids and alditol acetates resulting from analysis of the sugar moiety of glycolipids and glycoproteins can also be gas chromatographed on these phases.     

Einfluß von Licht und Tocopherolgehalt auf die Oxidationsstabilität von Fettsäuremethylestern

Influence of light and contents of tocopherols on the oxidative stability of fatty acid methyl esters The oxidative stability of different plant oil based fatty acid methyl esters can be estimated by determining the induction period with the active oxygen method. Measuring the volatile and oil soluble acids for a long period preceding the induction period shows that the values are approaching a certain limit. Even if the esters do not differ dramatically in the composition of fatty acids it is a fact that the different production processes influence the amount of tocopherols significantly. The exclusion of light is more crucial than the exclusion of air when storing plant oil based fatty acid esters.     

Diels-Alder adducts from safflower oil fatty acids

Methyl esters of alkali-isomerized safflower oil fatty acids after elaidinization with sulfur were treated with styrene in the presence of hydroquinone, with or without solvents. A combination of column chromatography and gas liquid chromatography techniques was employed for the estimation of the methyl esters of unreacted fatty acids, Diels-Alder adduct and polymers in the reaction products. Maximum yield of the Diels-Alder adduct (26.6%) was obtained when the elaidinized methyl esters of the fatty acids were treated with 1.5 moles of styrene per mole of linoleic acid in safflower oil fatty acids at 200–210 C for 6 hr. The methyl ester of the adduct was isolated in about 90% purity from the reaction product by vacuum distillation followed by solvent fractionation. The butyl ester of the adduct and the epoxy derivative of the methyl ester adduct were prepared and characterized.     

Solvent-Assisted Crystallization of Fatty Acid Alkyl Esters from Animal Fat

An easy and efficient method for the separation of saturated and unsaturated fatty acid mono alkyl esters, prepared from animal fat, was developed. The most efficient separation was achieved by the use of solvents such as methanol and acetone at low temperatures. The dilution of the alkyl esters with 10 times the amount of solvent (10:1 v/w) and storage of the mixture for 4 h at ?22 °C could be defined as optimum conditions. After filtration of the saturated fraction at the corresponding temperature very pure fractions were obtained. For fatty acid methyl esters deriving from tallow, with an initial content of saturated fatty acids of almost 50 %, a saturated ester fraction with only 5 % unsaturated fatty acids and an unsaturated ester fraction with about 9 % of saturated fatty acids could be obtained. The solvent easily could be recovered by distillation. In addition fatty acid ethyl, 1‐propyl, 2‐propyl, 1‐butyl, tert‐butyl and 3‐methyl‐1‐butyl esters were prepared and separated into saturated and unsaturated fractions. All fractions were analyzed according to the fatty acid compositions and showed similar or slightly worse results compared to the methyl esters. The cold filter plugging points of the unsaturated fractions were measured, showing the lowest value for the unsaturated methyl ester fraction at ?26 °C. The fractionation with the use of solvents is an easy tool in order to obtain fatty acid alkyl esters with excellent cold temperature behavior out of animal fat.     

Die Beeinflussung der Reaktion bei der Oxäthylierung von Fettsäuremonoäthanolamiden

Influencing the Oxyethylation Reaction of Fatty Acid Mono-Ethanolamides In the reaction of fatty acids or methyl esters of fatty acids with mono-ethanolamine, fatty acid-aminoethyl esters and di-fatty acid-ethanolamide esters are formed in addition to mono-ethanolamides of fatty acids. The equilibrium is predominantly towards the mono-ethanolamide of fatty acid. This equilibrium reaction interferes considerably during the oxyethylation of ethanolamides of fatty acids, since at the temperature of oxyethylation the aforestated compounds and their oxyethylation products are formed. Furthermore, amino-oxyethylate and heterocyclic products are always formed which lead to dark and odorous reaction products. Investigations were carried out in order to determine the influence of reaction temperature, catalyst concentration, and nature of starting material on the composition of oxyethylates that are formed by oxyethylation of fatty acid ethanolamides.     

Regioselektive C-H-Funktionalisierung von Fettsäuren und Fettsäuremethylestern

Regioselective C-H-Functionalization of Fatty Acids and their Methyl Esters Fatty acids and thier methyl esters can be chlorinated preferentially at the terminal methylene groups with N-alkylchloroamines in sulfuric acid. With capric acid and its methyl ester the optimal reaction conditions for the selective chlorination were elaborated and then transferred to longer fatty acids up to stearic acid. The influence of the solvent, the temperature and the nature of different chlorinating reagents on the selectivity was studies. The capillary GC/MS-analysis of the isomeric chlorinated fatty acids is described.     

Analytik und Biophysik von verzweigtkettigen Fettsäuren in Lipiden

Analytics and biophysics of branched fatty acids in lipids . Objects of our investigations are long chain fatty acids with methyl groups in different positions and fatty acids with a different length of the sidegroup in α-position. The separation of racemic branched fatty acid methyl esters by gas chromatography on a chiral column depends on the structure of the branched fatty acid. Diastereomeric amides and phosphatidylcholines with α-branched fatty acid residues were separated preparatively. The branched fatty acids were incorporated into 1,2-diacyl-, 1-acyl-2-hexadecyl- and 2-acyl-1-hexadecyl-glycerophosphocholines and characterized by differential scanning calorimetry and X-ray diffraction.     

Preparation of heptadecenoic acid fromCandida tropicallis yeast

In this paper a method is described for preparing 10 g or more of heptadecenoic acid (C17:1ω8) of 99 p.100 purity fromCandida tripicallis yeast. Three cycles of treatment, based on crystallization techniques, were used successively: (1) Crystallization of fatty acids (in free form) from acetone at −25 C induced the elimination of most of the saturated fatty acids, and at −60 C, of all of the poly-unsaturated acids. (2) Inclusion formation of fatty acids (as methyl esters) with urea at hC induced the removal of all of the remaining saturated methyl esters and most of methyl oleate. (3) Crystallization of fatty acid methyl esters from acetone at −60 C removed almost all the remaining monounsaturated methyl esters (methyl palmitoleate and methyl oleate). Total efficiency of the preparation was about 17 p. 100.     

Occurrence of Hexacosapolyenoic Acids 26:7(n‐3), 26:6(n‐3), 26:6(n‐6) and 26:5(n‐3) in Deep‐Sea Brittle Stars from Near the Kuril Islands

Significant amounts of polyunsaturated fatty acids (PUFA) with a chain length of 26 carbon atoms were detected in lipids of five deep water species of Ophiuroidea besides common fatty acids with chain lengths between 14 and 24. By means of hydrogenation, GC–MS of the methyl esters, and 4,4‐dimethyloxazoline (DMOX) derivatives of these C26 acids were characterized as 5,8,11,14,17,20,23‐hexacosaheptaenoic [26:7(n‐3)]; 8,11,14,17,20,23‐hexacosahexaenoic [26:6(n‐3)]; 5,8,11,14,17,20‐ hexacosahexaenoic [26:6(n‐6)]; and 11,14,17,20,23‐hexacosapentaenoic [26:5(n‐3)]. Concentrations of these acids varied from 0.3 to 4.5 mol% of the total FA. In all the samples investigated, the main component of C26PUFA was hexacosaheptaenoic acid 26:7(n‐3). These C26PUFA are localized mainly in polar lipids. The presence of the possible biosynthesis precursors suggests that the C26PUFA are produced by the brittle stars, and are not accumulated from food sources. This finding can also explain the presence of small amounts of the 26:7(n‐3) acid detected earlier in flesh lipids of the roughscale sole Clidoderma asperrimum, which feeds on deep water brittle stars. We suggest a possible scheme of the biosynthesis of C26 PUFA.     

A study of fatty acid methyl esters with epoxy or alkyne functionalities

Described are the physical and chemical properties of the methyl esters of two uncommon fatty acids: vernolic acid, containing an epoxy group, and crepenynic acid, containing a triple bond. The incorporation of an epoxy or alkyne group into the fatty acid structure is shown to greatly affect the properties compared to conventional unsaturated fatty acids. The methyl esters have been characterized and compared with ordinary fatty acid methyl esters (i.e., methyl oleate and linoleate) with respect to spectroscopic characterization [¹H nuclear magnetic resonance (NMR)], ¹³C NMR, and Fourier transform infrared), rheological properties, and oxidative reactivity (using chemiluminescence). Both methyl vernoleate and methyl crepenynate could successfully be produced by transesterification under basic conditions without reaction of the epoxy or alkyne groups. Rheological measurements showed that the methyl esters had a significantly lower viscosity compared to their triglyceride analogs. Smaller differences were seen when comparing the different methyl esters where methyl vernoleate had the highest viscosity due to the presence of the more polar oxirane group. Very large differences were found with respect to the oxidation rate of the different methyl esters. Methyl crepenynate was shown to oxidize extremely rapidly, whereas methyl vernoleate was very stable toward oxidation.     

Über trans-Lipoide: Die Lipoide des Hühnerei-Dotters

Trans Lipids: The Egg Yolk Lipids of the Hen The feeding of hens with a trans-containing edible fat resulted in an increase in the trans fatty acids of the egg yolk lipids to the extent of 10%, which completely disappeared within 14 days after stopping the trans-containing feed. The fatty acids in the triglyceride fractions contained in each case more trans unsaturated fatty acids than those in the corresponding phosphatide fractions. The gas chromatographic analysis of the fatty acid methyl esters showed that the triglycerides contained more oleic acid than the phosphatide fatty acids whereas stearic as well as polyunsaturated components were concentrated predominently in the phosphatides. The analysis of the fatty acid methyl esters from triglyceride and phosphatide fractions after feeding of trans-containing fat showed distinct changes in both the groups, thus for example a reduction of oleic acid in the neutral fat analogous to that in the total lipids as against its increase in phosphatides. The amount of linoleic acid in the phosphatide fatty acids increased while it remained constant in triglyceride fatty acids.     

Diels-Alder Adducts from Safflower Oil Fatty Acid Methyl Esters Using Aldehyde Dienophiles

The Diels-Alder reaction between alkali conjugated and elaidinised safflower oil fatty acid methyl esters and acrolein, crotonaldehyde and cinnamaldehyde was studied under various experimental conditions. A combination of column chromatography and gas liquid chromatography techniques was employed for the estimation of the methyl ester of the unreacted fatty acids, Diels-Alder adducts and polymeric and other materials in the reaction products. The maximum yields of the Diels-Alder adducts with acrolein, crotonaldehyde and cinnamaldehyde were 40.2, 44.4 and 52.2 per cent respectively when the reaction is carried out at 240°C for 6–8 hours using 2 moles of dienophile. The methyl esters of the adducts were isolated in about 90 per cent purity from the reaction products by distillation under reduced pressure followed by solvent fractionation.     

Chemoenzymatic epoxidation of unsaturated fatty acid esters and plant oils

In the presence of an immobilized lipase fromCandida antacrtica (Novozym 435^R) fatty acids are converted to peroxy acids by the reaction with hydrogen peroxide. In a similar reaction, fatty acid esters are perhydrolyzed to peroxy acids. Unsaturated fatty acid esters subsequently epoxidize themselves, and in this way epoxidized plant oils can be prepared with good yields (rapeseed oil 91%, sunflower oil 88%, linseed oil 80%). The hydrolysis of the plant oil to mono- and diglycerides can be suppressed by the addition of a small amount of free fatty acids. Rapeseed oil methyl ester can also be epoxidized; the conversion of C=C-bonds is 95%, and the composition of the epoxy fatty acid methyl esters corresponds to the composition of the unsaturated methyl esters in the substrate. Based partly on a lecture at the 86th AOCS Annual Meeting & Expo, San Antonio, Texas, May 7–11, 1995.     

Analysis of hydroxylated fatty acids from plant oils

A novel process has been described recently for the preparation of hydroxylated fatty acids (HOFA) and HOFA methyl esters from plant oils. HOFA methyl esters prepared from conventional and alternative plant oils were characterized by various chromatographic methods (thin-layer chromatography, high-performance liquid chromatography, and gas chromatography) and gas chromatography-mass spectrometry as well as¹H and¹³C nuclear magnetic resonance spectroscopy. HOFA methyl esters obtained fromEuphorbia lathyris seed oil, low-erucic acid rapeseed oil, and sunflower oil contain as major constituents methylthreo-9,10-dihydroxy octadecanoate (derived from oleic acid) and methyl dihydroxy tetrahydrofuran octadecanoates, e.g., methyl 9,12-dihydroxy-10,13-epoxy octadecanoates and methyl 10,13-dihydroxy-9,12-epoxy octadecanoates (derived from linoleic acid). Other constituents detected in the products include methyl esters of saturated fatty acids (not epoxidized/derivatized) and traces of methyl esters of epoxy fatty acids (not hydrolyzed). The products that contain high levels of monomeric HOFA may find wide application in a variety of technical products.     

Heats of Combustion of Fatty Acids and Fatty Acid Esters

The military uses JP-8, a kerosene type hydrocarbon, to fuel most of its vehicles and is seeking a renewable alternative fuel that meets strict JP-8 specifications. Biodiesel is typically a mixture of different alkyl esters produced from the transesterification of triglycerides readily available in plant oils and used cooking oil. To date, no traditional biodiesel meets the requirements for heat of combustion, freezing point, viscosity and oxidative stability to be a stand-alone replacement for JP-8. This work is a fundamental survey of the heat of combustion of single fatty acid esters and a predictive model for estimating the heat of combustion given a known molecular structure. The gross heat of combustion of various C6–C18 fatty acids and the methyl, propyl and isopropyl esters of these fatty acids was measured. This study sought to relate the effect of chain length, degree of unsaturation and branching to the critical fuel property of the gross heat of combustion (H _c). It was found that H _c (kJ/g) increased with chain length. A nearly linear relationship was found between wt% carbon and hydrogen, and H _c. Group contribution models previously published for hydrocarbons and polymers were modified to more accurately predict the heat of combustion of the fatty acids and esters. Modification of the molar heat values of carboxylic acid, methyl, and methylene groups improved correlation of the model with the experimental results.     

Methyl Esters (Biodiesel) from and Fatty Acid Profile of Gliricidia sepium Seed Oil

Increasing the supply of biodiesel by defining and developing additional feedstocks is important to overcome the still limited amounts available of this alternative fuel. In this connection, the methyl esters of the seed oil of Gliricidia sepium were synthesized and the significant fuel‐related properties were determined. The fatty acid profile was also determined with saturated fatty acids comprising slightly more than 35 %, 16.5 % palmitic, 14.5 % stearic, as well as lesser amounts of even longer‐chain fatty acids. Linoleic acid is the most prominent acid at about 49 %. Corresponding to the high content of saturated fatty acid methyl esters, cold flow is the most problematic property as shown by a high cloud point of slightly >20 °C. Otherwise, the properties of G. sepium methyl esters are acceptable for biodiesel use when comparing them to specifications in biodiesel standards but the problematic cold flow properties would need to be observed. The ¹H‐ and ¹³C‐NMR spectra of G. sepium methyl esters are reported.     

Hydrierung von Lipiden als Hilfsmittel zur Identifizierung und Quantifizierung von Phosphatiden aus Membransystemen des Herzmuskels

Hydrogenation of Lipids for Identification and Quantification of Phosphatides from Pellicle Systems of Cardiac Muscle. It was the aim of our research to show that hydrogenation of lipids is an auxiliary technique in phospholipid analysis of cardiac membranes. This is of interest if a preliminary overview on lipid fractions containing highly unsaturated fatty acids is needed. The fatty acids and the diglycerides from phospholipids were hydrogenated according to the procedure described by Appelqvist (A simple and convenient procedure for the hydrogenation of lipids on the micro- and nanomole scale, J. Lipid Res. 13 (1972), 146) with platinum oxide as a catalyst. The lipids (fatty acid methyl esters or acetylated diglycerides) were taken to dryness in a test-tube under nitrogen and flushed with hydrogen. The catalyst, suspended in methanol was injected through a septum. For identification purposes thin-layer chromatography on silica gel and on silica gel impregnated with silver nitrate was combined with gas chromatography before and after hydrogenation. After hydrogenation the fatty acid profile is much simpler and the fatty acid methyl esters can easily be differentiated from dimethyl acetals, as the latter are more volatile. Diacylglycerides and alkenylacylglycerides were also separated by thin-layer chromatography in individual subclasses before they were analysed by gaschromatography. Hydrogenating the lipids makes it possible to circumvent in part difficulties which arise often with polyunsaturated fatty acids. As the chain length of C20 and C22 are mainly represented by C20:4 , the arachidonic acid and C22:6 the docosahexaenoic acid, both fatty acids can be assessed after hydrogenation. The fatty acid profile of phosphatidylcholine and phophatidylethanolamine of cardiac muscle from rat, guinea pig and pig was determined. Each sample was analysed before and after hydrogenation. The fatty acids with the same chain length were summed up and compared to the corresponding chain length after hydrogenation.     

Die unterschiedliche Bedeutung der Fettsäuren in ihrer fungistatischen Wirkung

Significance of Fatty Acids in Their Fungistatic Action The fungistatic action of saturated and unsaturated fatty acids, halogenated fatty acids and esters as well as sulfurcontaining derivatives is reviewed. Fungistatic agents, known since a long time, are propionic acid, caprylic acid and its salts as well as undecylenic acid and its salts. The recently known fatty acid derivatives having fungistatic action are morpholine and piperidine compounds of long chain fatty acids and the new class of aminimides of fatty acids with 14–16 C atoms.