Thermal oxidation of synthetic triglycerides I. composition of oxidized triglycerides

Tripalmitin, 1- and 2-lauryl dipalmitin and 1- and 2-oleyl dipalmitin were subjected to thermal oxidation at 200C in the presence of air for various lengths of time. The triglycerides showed a loss in weight, and an increase in carbonyl hydroxyl and acid values. The I.V. increased in the case of saturated triglycerides and decreased in the case of unsaturated triglycerides. Hydrolysis of the ester linkage between glycerol and fatty acid was found to occur during thermal oxidation of the type and position of the fatty acid in the triglyceride molecule. The fatty acids released from the triglyceride by hydrolysis were found either to be oxidized further to short chain fatty acids, or were oxygenated with the introduction of a carbonyl or hydroxyl group in the molecule. Moreover, the unsaturated fatty acid in the triglyceride molecule was found to be oxidized more readily than the saturated fatty acid. A hydroxy fatty acid with a carbon number of 13.5 on a diethylene glycol succinate column was isolated from oxidized tripalmitin and was also found to occur in the free fatty acid fraction of oxidized tripalmitin, 1-lauryl, 2–3 dipalmitin, and 1-oleyl, 2–3 dipalmitin. The presence of laurie or oleic acid in the 2-position of the triglyceride prevented the formation of this acid, which suggested that it is an oxidation product of palmitic acid. Portion of a thesis presented by J. G. Endres as partial fulfillment of the requirements for the degree of Ph.D. in food technology. Funds for partial support of these studies were made available by the National Institute of Health, Grant A-1671.     

Volatile components from tristearin heated in air

Tristearin was heated to 192 C in air, and its volatile oxidation products were collected directly on a cooled (−60 C) gas liquid chromatography column. Subsequently, the volatile products were separated by temperature programing up to 250 C and identified by mass spectrometry. Methyl ketones and aldehydes were the major degradation products along with minor amounts of monobasic acids, n-hydrocarbons, primary alcohols, and γ-lactones. Qualitative results indicated all the fatty acid methylene carbon atoms are susceptible to oxidation. Quantities of aldehydes and ketones were found to be in excess of their taste threshold concentrations, suggesting thermally oxidized saturated fatty acids may be precursors of some odors and flavors associated with heated lipids. Presented at the AOCS Fall Meeting, Philadelphia, September 1974. ARS, USDA.     

Studies of jasmine wax: I. Physical properties and chemical composition

Jasmine wax was fractionated using thin layer chromatography. Six fractions were isolated, purified and identified using combined gas liquid chromatography and mass spectrometry. Infrared spectra were adopted for the chemical structure confirmation of each fraction. The fractions were 49.44% hydrocarbons, 15.73% esters, 3.49% aldehydes and ketones, 7.91% primary fatty alcohols, 8.31% free fatty acids and 8.99% was considered origin. The hydrocarbon fraction was found to consist mainly of saturated chains with C₂₉, C₃₁ and C₂₇ the most predominant. The aldehyde fraction was characterized by straight chains with even numbers of carbon atoms ranging between C₁₀ and C₂₈, whereas the ketone fraction was found to contain a longer chain structure, i.e., C₃₆. However, the C = O was found to be at the C₈ and C₁₁ positions. Free primary alcohols were found to occur in short chains, indicating their existence in the liquid phase, whereas the free fatty acids were found in long chains and were more likely in the solid phase.     

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.     

Fatty acid-specific, regiospecific, and stereospecific hydroxylation by cytochrome P450 (CYP152B1) from Sphingomonas paucimobilis: Substrate structure required for α-hydroxylation

Fatty acid α-hydroxylase from Sphingomonas paucimobilis is an unusual cytochrome P450 enzyme that hydroxylates the α-carbon of fatty acids in the presence of H₂O₂. Herein, we describe our investigation concerning the utilization of various substrates and the optical configuration of the α-hydroxyl product using a recombinant form of this enzyme. This enzyme can metabolize saturated fatty acids with carbon chain lengths of more than 10. The K _m value for pentadecanoic acid (C₁₅) was the smallest among the saturated fatty acids tested (C₁₀–C₁₈) and that for myristic acid (C₁₄) showed similar enzyme kinetics to those seen for C₁₅. As shorter or longer carbon chain lengths were used, K _m values increased. The turnover numbers for fatty acids with carbon chain lengths of more than 11 were of the same order of magnitude (10³ min⁻¹), but the turnover number for undecanoic acid (C₁₁) was less. Dicarboxylic fatty acids and methyl myristate were not metabolized, but monomethyl hexadecanedioate and ω-hydroxypalmitic acid were metabolized, though with lower turnover values. Arachidonic acid was a good substrate, comparable to C₁₄ or C₁₅. The metabolite of arachidonic acid was only α-hydroxyarachidonic acid. Alkanes, fatty alcohols, and fatty aldehydes were not utilized as substrates. Analysis of the optical configurations of the α-hydroxylated products demonstrated that the products were S-enantiomers (more than 98% enantiomerically pure). These results suggested that this P450 enzyme is strictly responsible for fatty acids and catalyzes highly stereo- and regioselective hydroxylation, where structure of ω-carbon and carboxyl carbon as well as carbon chain length of fatty acids are important for substrate-enzyme interaction.     

Direct determination of saturated fatty acids in fats,oils, and methyl esters

Summary A direct gravimetric method has been developed for the determination of saturated fatty acids in fats, oils, and methyl esters. The procedure involves methanolysis of the triglycerides to produce methyl esters, followed by oxidation of the unsaturated methyl esters by potassium permanganate. The undesired, acidic oxidation products are removed by alkaline washing and the saturated methyl esters thus isolated are weighed directly. The method is intended for the determination of saturated fatty acids having C₁₆ or longer carbon chains. Small quantities of C₁₄ saturated acids will be included in the determination if present with other higher saturated acids. The method is applicable to both natural and hydrogenated vegetable oils. It is not applicable to oils containing large amounts of C₁₄ and lower saturated acids. Concentrations of saturated acids ranging from 3 to 90% in known glyceride mixtures and from 0.3 to 95% in mixtures of methyl esters were determined with an average difference from the calculated value of 0.8%. Replicate determinations on samples in the 10 to 30% saturates range gave a standard deviation of 0.3 to 0.4%. Presented at the spring meeting, American Oil Chemists’ Society, New Orleans, La., April 28 to May 1, 1957     

Kerogen structure by stepwise oxidation: Use of sodium dichromate in glacial acetic acid

Green River shale kerogen was degraded by a careful five-step oxidation with sodium dichromate in glacial acetic acid. Products isolated from each oxidation step were examined by capillary gas chromatography and combined gas chromatography-mass spectrometry. The analyses revealed the presence of several homologous series. Saturated normal monocarboxylic acids (C₆C₃₅) and saturated normal α,ω-dicarboxylic acids (C₄C₃₃) were the major constituent series, while isoprenoid acids (C₁₄C₂₁, except C₁₈), iso and anteiso acids (C₆C₁₆), branched dicarboxylic acids (C₂₀C₂₉), triterpenoidal acids (C₂₇C₃₃), cyclic, and oxo-acids were the minor constituent series. Moreover, a few aromatic acids, branched ketones, heterocyclic compounds, as well as a series of (C₂₅C₃₀) n-alkanes were identified. The results were discussed in terms of the qualitative and quantitative variations of the products with duration of oxidation. The data corroborate the conclusion of a predominantly open chain crosslinked aliphatic structure for Green River kerogen, and indicate that aromatic structures are mainly in the form of isolated phenyl and tolyl groups. The results further confirm the presence of etioporphyrin as a significant constituent in the kerogen studied.     

Investigation of the structure of Estonian oil shale kukersite by conversion in aqueous suspension

Results of oil-shale liquefaction experiments by conversion in aqueous solutions of sodium formate and sodium hydroxide are discussed. The study of the decomposition products shows that not only fatty acids, C₁₄, C₁₆ and C₁₈, but also poly-unsaturated acids, C₂₀, C₂₂ and C₂₄ took part in the formation of kukersite. Additional data are presented to confirm the assumption that polycarbonyl structures are present in kukersite. On thermal decomposition (semi-coking) kukersite yields a considerable amount of 5-alkyl resorcinols. On conversion in aqueous suspension, however, ketones are formed instead of alkyl resorcinols. Kukersite is a rare caustobiolith, distinguished by the presence of significant amounts of unchanged fragments of biological precursor material, mostly decarboxylated alkyl chains of fatty acids.     

The positional distribution of fatty acids in the phospholipids and triglycerides ofMycobacterium smegmatis andM. bovis BCG

Position 1 of the phospholipid and triglyceride fractions isolated fromMycobacterium smegmatis andM. bovis BCG was esterified principally with C₁₈ related fatty acids (18∶0, 18∶1 and 19Br). Position 2 was occupied principally by C₁₆ fatty acids. The third position of the triglycerides was esterified with a preponderance of C₂₀+fatty acids. Seventysix per cent of position 3 fatty acids in BCG and 43% inM. smegmatis triglycerides contained fatty acids of greater than 20 carbon atoms.     

The composition of beeswax alkyl esters

The alkyl esters of beeswax, after isolation from the unhydrolyzed wax by preparative layer chromatography (PLC), have been analyzed directly by high temperature GLC using 1.5% OV1 as liquid phase. In two commercial wax samples examined the ester homologues are predominantly even carbon numbered ranging from C₃₆ to C₅₄. The principal alkyl esters are C₄₀, C₄₂, C₄₄, C₄₆ and C₄₈. The GLC analysis of the ester hydrolysis products revealed that the variations in ester chain length are produced by variations in the esterified primary alcohol chain lengths. The esterified fatty acid is chiefly hexadecanoic acid. The esterified fatty acids differ in composition from the free fatty acids which are also present in the wax.     

Liquid-phase oxidation of normal C<Subscript>10</Subscript>–C<Subscript>13</Subscript> hydrocarbons with hydrogen peroxide on the titanium-containing catalyst ts-1: The effect of process conditions on product composition

Severe economic challenges and stringent environmental regulations have made it necessary to devise new higher fatty alcohol synthesis technologies in order to replace the existing processes, which produce large amounts of waste, or to eliminate or considerably lessen their drawbacks. Processes using hydrogen peroxide, an environmentally friendly oxidizer, are of great interest in this respect. Here we report the effect of process conditions (the initial molar ratio of reactants and temperature) on the proportions of the products (alcohols and ketones) of the liquid-phase oxidation of normal C₁₀–C₁₃ hydrocarbons on a heterogeneous titanium-containing silicalite catalyst (TS-1). The main products of the reaction are alcohols and ketones, and the proportion of the alcohols in the reaction mixture decreases as the temperature is raised and as the hydrocarbon-to-hydrogen peroxide molar ratio is decreased.     

Distribution of individual fatty acids in the crystallization fractions of lard

Distribution of the individual fatty acids in the triglycerides of lard was determined by fractional crystallization, partial enzymatic hydrolysis with steapsin, and fatty acid analyses by GLC. It was found that none of the individual fatty acids corresponded to a random distribution in the crystallization fractions, but that the distribution of the total saturated and total unsaturated acids was very nearly random. The short chain fatty acids, C₁₄ and C₁₆, both saturated and unsaturated, were found to be more predominant in the 2-position than in the 1- and 3-positions of the lard triglycerides. All of the C₁₈ fatty acids were found to be more predominant in the 1- and 3-positions.     

3-thia fatty acid treatment, in contrast to eicosapentaenoic acid and starvation, induces gene expression of carnitine palmitoyltransferase-II in rat liver

The aim of the present study was to investigate the hepatic regulation and β-oxidation of long-chain fatty acids in peroxisomes and mitochondria, after 3-thia- tetradecylthioacetic acid (C₁₄-S-acetic acid) treatment. When palmitoyl-CoA and palmitoyl-l-carnitine were used as substrates, hepatic formation of acid-soluble products was significantly increased in C₁₄-S-acetic acid treated rats. Administration of C₁₄-S-acetic acid resulted in increased enzyme activity and mRNA levels of hepatic mitochondrial carnitine palmitoyltransferase (CPT)-II. CPT-II activity correlated with both palmitoyl-CoA and palmitoyl-l-carnitine oxidation in rats treated with different chain-length 3-thia fatty acids. CPT-I activity and mRNA levels were, however, marginally affected. The hepatic CPT-II activity was mainly localized in the mitochondrial fraction, whereas the CPT-I activity was enriched in the mitochondrial, peroxisomal, and microsomal fractions. In C₁₄-S-acetic acid-treated rats, the specific activity of peroxisomal and microsomal CPT-I increased, whereas the mitochondrial activity tended to decrease. C₁₄-S-Acetyl-CoA inhibited CPT-I activity in vitro. The sensitivity of CPT-I to malonyl-CoA was unchanged, and the hepatic malonyl-CoA concentration increased after C₁₄-S-acetic acid treatment. The mRNA levels of acetyl-CoA carboxylase increased. In hepatocytes cultured from palmitic acid- and C₁₄-S-acetic acid-treated rats, the CPT-I inhibitor etomoxir inhibited the formation of acid-soluble products 91 and 21%, respectively. In contrast to 3-thia fatty acid treatment, eicosapentaenoic acid treatment and starvation increased the mitochondrial CPT-I activity and reduced its malonyl-CoA sensitivity. Palmitoyl-l-carnitine oxidation and CPT-II activity were, however, unchanged after either EPA treatment or starvation. The results from this study open the possibility that the rate control of mitochondrial β-oxidation under mitochondrion and peroxisome proliferation is distributed between an enzyme or enzymes of the pathway beyond the CPT-I site after 3-thia fatty acid treatment. It is suggested that fatty acids are partly oxidized in the peroxisomes before entering the mitochondria as acylcarnitines for further oxidation.     

2-Alkylcyclobutanones from the radiolysis of triglycerides

A cyclic compound was isolated from the radiolytic products of each of the simple triglycerides containing C₆, C₈, C₁₀, C₁₂, C₁₄, C₁₆ and C₁₈ fatty acids. In each case the compound was identified as the 2-alkylcyclobutanone of the same carbon number as the precursor fatty acid. A mechanism is proposed for the production of these compounds which involves the formation of a six-membered ring intermediate, cyclization and cleavage at the acyl-oxy bond.     

GC-MS Identification of Organic By-Products of the NO SCR by Propene; Relation to N2O Formation

Reduction of NO by propene in the presence of oxygen and water was studied on a Pt/Al₂O₃ catalyst in the following conditions (ppm (v)): NO/C₃H₆/O₂/H₂O = 800/500/50000/50000. The organic products accompanying N₂, N₂O and NO₂ formation were trapped and analyzed by GC-MS. These analyses revealed the presence in small quantities of products of propene partial oxidation such as ketones or acids, nitrogen derivatives such as nitriles or/and nitro and nitroso compounds. The transformation of some nitrogen-containing derivatives were studied under reaction conditions to explain the formation of the by-products and of N₂O.     

Wirkungsmechanismus langkettiger Monoenfettsäuren im Energiestoffwechsel des Herzens

Mechanism of Long Chain Monoenoic Fatty Acids Acting on the Energy Metabolism of Heart The oxidation of 1-¹⁴C-erucic (C_22:1) and 1-¹⁴C-nervonic (C_24:1) acids was studied in comparison to 1-¹⁴C-palmitic and -oleic acids in isolated rat and pig heart mitochondria. After mitochondrial incubation with the albumin-bound fatty acids only small amounts of ¹⁴CO₂ developed from the oxidation of the long chain monoenoic acids as compared to palmitic or oleic acid. The slow down of the oxidation rate was more pronounced in rat than in pig heart mitochondria. The oxidation of palmitic or oleic acid was not found to be inhibited by the C²⁰–C²⁴-monoenoic acids, whereas palmitic or oleic acid inhibited the oxidation of erucic acid competitively. From present findings an idea may be developed of the interference on fatty acid metabolism in heart muscle by erucic and other long chain monoenoic acids.     

New developments in synthetic fatty acids

New developments in synthetic fatty acids have occurred in the last few years in Russia, Japan, the United States and Canada. In 1959 Russia decided to replace 40% of natural fatty acids in soaps with synthetic fatty acids. In 1966, 548 million pounds of C₅–C₃₀ synthetic fatty acids were produced including 288 million pounds of C₁₀–C₂₀ fatty acids. Forty million pounds of fatty acids are converted directly to the fatty alcohols for detergent use. A conservative estimate predicts that one billion pounds of synthetic fatty acids will be produced in Russia by the end of the current five-year program. Reports say that the Japanese have been interested in the oxidation of not only paraffin hydrocarbons but naphthenic petroleum hydrocarbons as well. Production of lower homology fatty acids up to butyric acid is being seriously considered in Japan. In America the most likely syntheses aside from “oxo” syntheses being considered for the manufacture of products like lauric acid is the carboxylation of the Ziegler intermediates prepared from ethylene polymerization. Some data on the current and future coconut oil consumption by major end-use for Canada and the United States are presented. Synthetic lauric acid is predicted for 1970 in the United States. Prepared from an address given at a meeting of the Northeast Section, New York, June 1968.     

Full Characterisation of Crambe abyssinica Hochst. Seed Oil

This work was dedicated to reporting the full chemical and physical characterisation of Crambe abyssinica Hochst. seed oil. The oil from the seeds was extracted using n-hexane. The seeds contain about 30?% oil. Density, refractive index, colour, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, the relative position of fatty acids in C₁ and C₃ carbon glycerol, sterols, tocopherols, peroxide value, $ \mathop E\nolimits_{{1{\text{cm}}}}^{1\,\% } $ at 232?nm, and the susceptibility to oxidation measured by the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially C22:1 (63.77?%). The dominant saturated acid was C22:0 (2.14?%). The oil was also found to contain high levels of β-sitosterol (51.93?%), campestanol (21.98?%), and brassicasterol (12.35?%). α-, γ-, and δ-Tocopherols were detected up to levels of 7.67, 125.04, and 3.99?mg/kg, respectively. The induction period (at 110?°C and 20?l/h) of the oil was 8.83?h. The relative position of fatty acids in C₁ and C₃ position was as follows: linoleic 0.45?%, oleic 8.84?%, and erucic 90.72?%. The thermal profile of the oil presented a single peak at ?20.94?°C.     

Hydroxy acids and estolide triglycerides ofHeliophila amplexicaulis L.f. Seed oil

Thirty percent of the fatty acids fromHeliophila amplexicaulis seed oil are hydroxy acids, primarily lesquerolic acid (14-hydroxy-cis-11-eicosenoic acid) with a trace of a new fatty acid, 16-hydroxy-cis-13-docosenoic acid. The hydroxy acids in the oil are found exclusively in the 1 and/or 3 positions of the triglycerides and are completely acylated with C₂₀ or C₂₂ saturated or monoenoic acids. The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

The Occurrence of Fatty Acids in Fulvic Acid,A Soil Humic Fraction

Normal fatty acids ranging from C₁₄ to C₃₆ were found to account for a maximal 0.10% of the dry ash-free weight of a water soluble soil fulvic acid. Only 10.0% of the total fatty acids could be extracted by organic solvents from untreated fulvic acid. The remaining 90.0% was extractable only after methylation of the fulvic acid and adsorption on neutral aluminum oxide. While the nature of the molecular forces that hold the fatty acids to the fulvic acid is still a matter of conjecture, evidence was obtained that reduction of hydrogen bonding by methylation was related to the release of fatty acids by the fulvic acid. Ninety-five percent of the acids that were isolated were saturated, the remaining 5.0% were unsaturated and branched-cyclic. The C₂₄ acid was the major component. The overall C-even to C-odd carbon atom ratio for all acids was 2.3. The results suggested two different origins for the fatty acids: the C₁₄ to C₂₆ acids may be of microbiological origin, whereas the C₂₇ to C₃₆ acids may have arisen from plants. Weight distribution plots of fatty acids and n-alkanes extracted from the fulvic acid showed an inverse concentration relationship between the two components with identical carbon numbers. The data reported herein suggest that fulvic acid may act as a vehicle for the mobilization, transport and immobilization of water-insoluble organic compounds—some of which may be serious pollutants—in an aquatic environment.