Component fatty acids of marine fish liver oils

Summary 1. Two liver oils (Elasmobranch) fromCarcharias melanopterus andPristis cuspidatus, caught off the Madras coast are studied, and their component fatty acids are reported. 2. The mixed acids were separated into three groups (varying unsaturation) of acids, and their methylesters were fractionated. 3. The liver oils are found to belong to the fourth group of Tsujimoto’s classification of Elasmobranch fish liver oils.Carcharias melanopterus liver oil contains 31.1% unsaturated acids (myristic 3.1, palmitic 18.4, stearic 9.5, and 0.1% arachidic) and 68.9% unsaturated acids (C₁₆ 10.8, C₁₈ 19.7, C₂₀ 15.2, C₂₂ 17.1, C₂₄ 5.3%, and traces of C₁₄ monoethenoid).Pristis cuspidatus liver oil contains 36.9% saturated acids (myristic 1.2, palmitic 22.9, stearic 12.7, and arachidic 0.1%) and 67.1% unsaturated acids (C₁₆ 8.2, C₁₈ 28.5, C₂₀ 16.4, C₂₂ 5.2, C₂₄ 4.6%, and traces of C₁₄ monoethenoid). The unsaturations of the different groups of acids are almost of the same order. 4. The abnormal content of saturated acids can be explained by the process of bio-hydrogenation. The relatively less amount of saturated acids inCarcharias melanopterus liver oil along with its higher content of polyethylenic acids (C₂₀ and above) points strongly to the possible presence of intermediate types of fats among the four groups of Elasmobranch oils.     

The fungicidal activity of the unsaturated fatty acids and quaternary salts prepared from fish oils

Summary Saturated and unsaturated fatty acids and 10 unsaturated fatty acid fractions and ethyl esters of unsaturated fatty acid fractions prepared from fish oils were tested on their inhibitory activity againstCandida albicans. Oxidation of highly unsaturated fractions from fish oil and ethyl esters of unsaturated fatty acid fractions of menhaden, pilchard, and cod liver oils increases their antifungal activity. Saturated and unsaturated quaternaries were tested for their antifungal activity. Hexadecyltriethylammonium bromide and hexadecylpyridinium bromide showed the highest activity againstCandida albicans, Aspergillus niger, andRhyzopus nigricans. Any lengthening of the carbon chain more than C₁₆ weakened the activity of both saturated triethylammonium bromide and pyridinium bromide. An increase of unsaturation enhanced it. The antifungal activity of quaternaries prepared from fish oils was about 4,000 times stronger than that of oxidized highly unsaturated fatty acid fractions prepared from fish oils. The decisive factor in the highly inhibitory activity of quaternaries against fungi might depend on their positively charged portion since the surface of microorganisms is, as a rule, negatively charged. Aided by a grant from the Collett-Week Company, Ossining, N. Y.     

Fractional vacuum distillation of herring oil methyl esters

Methyl esters of a Canadian Atlantic herring oil containing 62% monoethylenic fatty acids were subjected to batch fractional distillation under vacuum on a pilot plant scale, to study the feasibility of fractionating fatty acid esters of marine oils of low iodine value into monounsaturated fractions with increased commercial value for industrial chemical uses. A total of 64 methyl ester fractions were collected and analyzed by gas liquid chromatography. Recoveries of the major saturated and monounsaturated acids were close to 100%, and some fractions contained over 90% of the desired 22:1 long chain monounsaturated acids. The short chain polyunsaturated acids were recovered in good yields, but the long chain highly unsaturated acids were recovered in yields of 60% or less due to oxidative and thermal decomposition in the particular apparatus employed. If small amounts of unsaturated acids are acceptable, fractional distillation of low iodine value marine oils could inexpensively supply fractions with high concentrations of methyl esters of longer chain (C₂₀ and C₂₂) monounsaturated and shorter chain (C₁₄) saturated acid or (C₁₆) saturated-monounsaturated acid mixture.     

Novel branched-chain fatty acids in certain fish oils

Methyl-branched fatty acids, which are usually minor components (≤0.1%) in fish oils, were concentrated in the non-urea-complexing fraction along with polyunsaturated fatty acids during the enrichment of omega-3 fatty acids from certain fish oils via the urea complexation process. The methyl-branched fatty acids in the omega-3 polyunsaturated fatty acid concentrates, which were prepared from three fish body oils, were characterized by gas chromatography and gas chromatography/mass spectrometry. Among the major branched-chain fatty acids expected and identified were the known isoprenoid acids—mainly 4,8,12-trimethyltridecanoic, pristanic, and phytanic—and the well-known iso and anteiso structures. Two novel phytol-derived multimethyl-branched fatty acids, 2,2,6,10,14-pentamethylpentadecanoic and 2,3,7,11,15-pentamethylhexadecanoic, were identified in redfish (Sebastes sp.) oil. These two fatty acids were absent in oils from menhaden (Brevoortia tyrannus) and Pacific salmon (mixed, but mostly from sockeye,Oncorhynchus nerka). The major branched-chain fatty acid in the salmon oil, 7-methyl-7-hexadecenoic acid, was also present to a moderate extent in menhaden oil. A novel vicinal dimethyl-branched fatty acid, 7,8-dimethyl-7-hexadecenoic was detected in all of the fish oils examined, but was most important in the salmon oil. Three monomethyl-branched fatty acids, 11-methyltetradecanoic acid, and 11- and 13-methylhexadecanoic, hitherto undescribed in fish lipids, were also detected in salmon, redfish and menhaden oils. Presented in part at the First Annual Meeting of the Amer. Oil. Chem. Soc. Canadian Section, Guelph, Ontario, Oct. 8–9, 1986.     

Jojoba oil wax esters and derived fatty acids and alcohols: Gas chromatographic analyses

HCl-catalyzed ethanolysis followed by saponification readily surmounts the resistance of long chain wax esters to direct hydrolysis by alkali. Additionally, choosing ethyl instead of methyl esters allows baseline separations between long-chain alcohols and corresponding esters in gas liquid chromatographic (GLC) analysis of total alcohol and acid components before saponification. Liquid wax esters were analyzed on a temperature-programmed 3% OV-1 silicone column. Geographical and genetic effects on the variability of jojoba oil composition were investigated with five different seed samples. Major constituents in jojoba seed oil from shrubs in the Arizona deserts, as indicated by GLC analyses of oil, ethanolysis product, isolated fatty alcohols and methyl esters of isolated fatty acids, were C₄₀ wax ester 30%, C₄₂ wax ester 50% and C₄₄ wax ester 10%; octadecenoic acid 6%; eicosenoic acid 35%, docosenoic acid 7%, eicosenol 22%, docosenol 21% and tetracosenol 4%. Oil from smaller leaved prostrate plants growing along California’s oceanside showed a slight tendency toward higher molecular size than oils from the California desert and Arizona specimens. The wax esters are made up of a dispro-portionately large amount of docosenyl eicosenoate and are not a random combination of constituent acids and alcohols.Lunaria annua synthetic wax ester oil was used as a model for evaluating the analytical procedures. Presented at the AOCS Meeting, Chicago, September 1970 No. Utiliz, Res. Dev. Div., ARS, USDA.     

Observations on Component Fatty Acids of Indian Sardine Oil and its Upgraded Samples

Three samples of sardine oil — one obtained by extraction of the whole body of sardine fish and the other two by upgrading of the former by different methods — were analysed using chromatographic techniques for their fatty acid compositions. The fatty acids ranging in chain lengths from C₁₂ to C₂₂ and in unsaturation from 0 to 6 double bonds were found in these oils. A few odd-numbered fatty acids were also detected. Higher proportions of polyenoic acids were noticed in solvent-winterised oil than in filtered sample.     

Lipase selectivity toward fatty acids commonly found in fish oil

The main objective of this study was to compare the fatty acid selectivity of numerous commercially available lipases toward the most ubiquitous fatty acids present in fish oils in form of their corresponding ethyl esters. Special interest was taken in their ability to separate the n‐3 long‐chain polyunsaturated fatty acids (PUFA), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from the more saturated fatty acids as well as exploiting the putative discrimination between these highly valuable n‐3 PUFA. Hydrolysis of sardine oil ethyl esters in a Tris buffer solution by 12 microbial lipases is described. The results reveal that all of the lipases strongly discriminate against the n‐3 PUFA and prefer the more saturated fatty acids as substrates. Most of the lipases discriminate between EPA and DHA in favor of EPA, however, 2 bacterial lipases from Pseudomonas were observed to prefer DHA to EPA. Digestive lipolytic enzymes isolated from salmon and rainbow trout intestines displayed reversed fatty acid selectivity when their fish oil triacylglycerol hydrolysis was studied. Thus, the n‐3 PUFA including EPA and DHA were observed to be hydrolyzed at a considerably higher rate than the more saturated fatty acids.     

Isomers of monoethylenic fatty acids in some partially hydrogenated marine oils

An analytical study of the monoethylenic isomers in commercial samples of partially hydrogenated herring, whale and seal oils is presented. The results show that with hydrogenated herring oil there is a slight decline in monoenetrans content from 37% in C₁₆ through to 32% in C₂₂. With both whale and seal oils, monoenetrans contents were constant at 54% and 59%, respectively, throughout all chain lengths. In general thecis andtrans positional isomers from hydrogenated whale and seal oils were more scattered than those from hydrogenated herring oil; however in each oil the majorcis isomers of each chainlength were indicative of originalcis fatty acid isomers in the raw oils.     

Fatty acid composition of danish margarines and shortenings,with special emphasis ontrans fatty acids

Trans fatty acids from hydrogenated vegetable and marine oils could be as hypercholesterolemic and atherogenic as saturated fatty acids. Hence, it is important to know the fatty acid composition in major food contributors, e.g., margarines and shortenings. In 1992 margarines were examined, and in 1995 brands covering the entire Danish market were examined. Significant amounts oftrans-18∶1 were found only in hard margarines (mean: 4.2±2.8%) and shortenings (mean: 6.8 ±3.1%), whereas the semisoft and soft margarines contained substantially lesstrans-18∶1 in 1995 than in 1992. Where marine oils had been used to a larger degree the meantrans-monoenoic content was about 15%, of which close to 50% was made up of long-chain (C₂₀ and C₂₂)trans fatty acids. A note-worthy decrease in the content oftrans-18∶1 had occurred for the semisoft margarines, from 9.8±6.1% in 1992 to 1.2±2.2% in 1995. Calculated from sales figures, the supply oftrans-18∶1 plus saturated fatty acids from margarines had decreased over this three-year period by 1.4 g/day, which has been replaced bycis monounsaturated and polyunsaturated fatty acids.     

A simple photometric method for microdetermination of fatty acids in lipids

A single step photometric micromethod for determination of fatty acids in lipids in benzene solution, using rhodamine 6G reagent, has been developed. The method eliminates the disadvantage of formation of a biphasic system and is applicable in the presence of glycerides, sterols, epoxy compounds, hydrocarbons and long chain hydroxy compounds such as long chain fatty alcohols. The long chain fatty acids from C₁₂ to C₂₂, both saturated and unsaturated, can be determined with reasonable accuracy in the concentration range of 0.08–0.25 μmole/ml. The method is simple, rapid, and requires relatively inexpensive chemicals.     

Antimicrobial lipids: Natural and synthetic fatty acids and monoglycerides

Over 40 natural or synthetic lipophilic compounds were screened for antimicrobial activity. Gram (+) bacteria and yeasts but not Gram (−) bacteria were affected by these agents. Epimino and selena fatty acids are more active than their corresponding straight chain unsubstituted fatty acids. The position of selenium influenced the antimicrobial activity of the fatty acid. The presence and position of a double or triple bond, usually an important factor in long chain fatty acids (>C₁₄) had little or no effect in C₁₁ fatty acids. Optimum antimicrobial activity was found for fatty acids and their corresponding monoglycerides when the chain length was C₁₂. The dilaurin derivative was not active.     

Cardiac fatty acids in rats fed marine oils

Cardiac fatty acids were studied in young rats fed marine oils for 1 week. When the diet contained 0, 0.5, 1, 2, 4, 8 or 16% by weight of partially hydrogenated oil from Norwegian capelin, the concentration of fatty acids in the cardiac tissue was elevated only at the highest level. The amount of the lipid and the content of docosenoic acid in the heart were less than those observed with 15% partially hydrogenated oil from Canadian herring. Nonhydrogenated Peruvian anchovy oil lacking docosenoic acid produced no change in the amount of fat deposited. The extent of fatty acid accumulation in the heart was related to the dietary C₂₂ acids.     

Isomeric monoethylenic fatty acids in herring oil

Monoethylenic fatty acids from herring oil were concentrated by chromatography by chromatography on silver nitratesilicic acid columns. Examination of consecutive fractions by open tubular gas chromatography confirmed the preferential elution of longer chain length esters and of esters within one chain length with the double bond closer to the terminal methyl group. Isomeric monoethylenic fatty acids with double bonds in the positions closer to the carboxyl group than the approximate midpoint of the even-numbered fatty acid chains could not be adequately separated by gas chromatography and were determined by ozonolysis. The isomers observed are consistent with primary formation from saturated acids through the action of an enzyme specifically removing hydrogen atoms in positions Δ⁹ and Δ¹⁰ relative to the carboxyl group. Chain extension of particular monoethylenic isomers by two carbon atoms in the C₂₀ and longer chain lengths is apparently influenced by the position of the double bond. This work was carried out in partial fulfillment of MSc requirements at Dalhousie University.     

Specific distribution of fatty acids in the milk fat triglycerides of goat and sheep

The triglycerides of the fat globules of sheep and goat milk were isolated and separated into short and long chain lengths by silicic acid column chromatography. The short chain lengths comprised major triglycerides with 34–44 acyl carbon atoms and accounted for nearly 50% of the total milk fat. The long chain lengths contained major triglycerides with 40–54 acyl carbons. Stereospecific analyses of the short chain triglyceride fraction showed that of the 20–23 moles per cent of C₄−C₈ fatty acids present, at least 95% were specifically attached to the glycerol molecule in the position corresponding to carbon 3 ofsn-glycerol. The distribution of the other fatty acids (C₁₀ or greater) did not show such marked specificity for either the 1 or the 2 position. Although individual triglycerides were not identified, the specific placement of the fatty acids could best the accounted for by assuming a common pool of long chain 1,2-diglycerides which served as precursors of the bulk of both short and long chain triglycerides during milk fat synthesis. Presented in part at the AOCS Meeting, New York, October 1968.     

Production of odd chain polyunsaturated fatty acids byMortierella fungi

A soil isolate,Mortierella alpina 1S-4, was found to show high production of odd chain polyunsaturated fatty acids (PUFAs) among various arachidonic acid-producingMortierella strains tested. The fungus mainly accumulated 5,8,11,M-cis-nonadecatetraenoic acid. With 5%n-hepta-decane and 1% yeast extract as growth substrates, the amount of C_19:4:4 acid accumulated reached 44.4 mg/g dry mycelia (0.68 mg/mL of culture broth). This value accounted for 11.2% of the total fatty acids in the extracted lipids from mycelia, and odd chain fatty acids comprised over 95% of the total mycelial fatty acids. The addition of sesamin, a specific inhibitor of A5 desaturation, caused an increase in C_19:3 acid and an accompanying decrease in C_19:4 acid. On the other hand, species ofMortierella that could not produce C-20 PUFAs accumulated C-17 acids, but no C-19 PUFAs, when grown with fatty substrates with an odd chain skeleton. The odd chain PUFAs were distributed in both neutral and polar lipids. The biosynthetic route to C_19:4 acid was presumed to mimic the n-6 route to arachidonic acid as follows: C_17:0 → C_17:1→ C_17:2→ C_17:3 → C_19:3 → C_19:4 acids. On leave from Suntory Ltd.     

Constituent fatty acids of salmon egg fat

Summary and Conclusions 1. The constituent fatty acids determined by the Hilditch method in the fat from the sample of pink salmon eggs are reported. Forty-five per cent of the fatty acids were 20 and 22 carbon atoms long, with an average unsaturation of 7.3 hydrogen atoms for the C₂₀ acids and 11.8 hydrogen atoms for the C₂₂ acids. 2. The Hammond and Lundberg correlation of refractive index, carbon chain length, and unsaturation was used to measure the alteration that occurred in the fatty acid esters of salmon egg fat during the vacuum distillation step of the Hilditch method of analysis. The alteration by heat of the unsaturate fraction in the vacuum distillation was significant even in the first overhead subfractions. Analysis by the Hilditch method resulted in low values for unsaturation and chain length of the constituent fatty acids in the unsaturated fat. The Fishery Products Laboratory is operated jointly by the U. S. Fish and Wildlife Service and the Alaska Fisheries Experimental Commission.     

Fatty acid desaturase systems of hen liver and their inhibition by cyclopropene fatty acids

Hen liver preparations which desaturate stearic acid at the 9,10 position to form oleic acid have been found to desaturate other saturated fatty acids of carbon chain length from 12 to 20 and 22. The 9,10-monoenoic fatty acid of the same chain length as the substrate fatty acid is the major product formed. Minor amounts of the 10,11- and 11, 12-monoenoic acids are also formed. Maximum desaturation occurred with the C₁₄ fatty acid substrate and with the fatty acids C₁₇ and C₁₈, suggesting the presence of at least two desaturating systems. The cyclopropene fatty acids, sterculic and malvalic acids, inhibited the desaturation of all thefatty acids at the 9,10 position but desaturation at the 10,11 and 11, 12 positions was affected only slightly. The effect is not due to inhibition of the primary activating enzyme, the long chain acyl CoA synthetase. Sterculic acid is a more effective inhibitor than either malvalic acid or sterculyl alcohol, probably because these cyclopropene compounds do not block the desaturating site of the enzyme as completely as sterculic acid.     

Gas-liquid chromatographic analysis of cyclopropene fatty acids

A gas-liquid chromatographic method is described for the quantitative estimation of cyclopropene fatty acids as their methyl mercaptan derivatives. This method estimates individual cyclopropene acids as well as normal and cyclopropane acids. Nine seed oils were analyzed for their cyclopropene fatty acid content. Evidence was obtained for the presence of a cyclopropene fatty acid of shorter chain length than malvalic inAlthaea rosea cav and one with a higher chain length than sterculic inBombacopsis glabra seed oil. This method is less accurate for cottonseed oil than for the other oils tested because of the appearance of some unsymmetrical peaks of unknown origin. The mercaptan derivatives of the cyclopropene acids may be isolated by silver ion thin-layer chromatography. Small amounts of cyclopropane fatty acids were found in a number of the oils analyzed for cyclopropene fatty acids. Presented at the AOCS meeting, Chicago, October 1964.     

Unsaturated C18 α-hydroxy acids inSalvia nilotica

The oil ofSalvia nilotica Jacq. (Labiatae) seed contains 0.6% α-hydroxyoleic, 4.2% α-hydroxylinoleic, and 5.4% α-hydroxylinolenic acids. The first two have not been found previously in seed oils. In addition to the common fatty acids, also identified were small amounts of three unsaturated C₁₇ acids and one branched chain C₁₇ acid. Methyl esters of the component fatty acids were fractionated by both column and thin-layer chromatography. These esters were identified by combination of gas chromatography, GC-mass spectrometry, ozonolysis-GC, infrared, and nuclear magnetic resonance.     

Component fatty acids of some cruciferae oils

Summary The oils from yellow mustard seed (Brassica alba), black mustard seed (Brassica nigra) of Indian origin, and rapeseed (Brassica Compestris) of unknown origin have been analyzed for their fatty acid composition without preliminary resolution of fatty acids by lead-salt-alcohol or fractional crystallization methods. The results compare very favorably with those determined by other recently developed methods. It may be concluded therefore that this method can be favorably employed for the determination of fatty acid composition of fats containing higher unsaturated acids. Confirmatory evidence has been obtained for the presence of eicosenoic acid in rapeseed oil. The nature and amount of fatty acids of yellow mustard seed oil of Indian origin do not differ in any significant manner from those of other cruciferous seed oils. The present analysis of black mustard seed oil reveals a higher amount of linolenic acid, and the presence of a C₂₀ monoethenoid acid, not heretofore reported. Contribution No. 708 from the Department of Chemistry, University of Pittsburgh. Presented in part at the Spring meeting of the American Oil Chemists’ Society, held in New Orleans, La., May, 1948. Baliga and Hilditch’s paper. “The Component Acids of Rapeseed Oil” (J. Soc. Chem. Ind.67, 258–262 (1948).