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1.
M. M. Mossoba R. E. McDonald J. A. G. Roach D. D. Fingerhut M. P. Yurawecz N. Sehat 《Journal of the American Oil Chemists' Society》1997,74(2):125-130
The trans octadecenoic acid methyl ester isomers were obtained from a partially hydrogenated soybean oil sample and isolated by silver-ion
high-performance liquid chromatography. The double bond configuration was confirmed to be trans by using gas chromatography-direct deposition-Fourier transform infrared spectroscopy. The double bond positions for nine
individual trans octadecenoic acid positional isomers were confirmed by gas chromatography-electron ionization mass spectrometry after derivatization
to 2-alkenyl-4,4-dimethyloxazoline. These nine trans positional isomers were resolved on either one of the two polar 100% cyanopropylpolysiloxane 100-m capillary columns, SP
2560 and Cp-Sil 88, at an isothermal temperature of 140°C. These nine isomers were confirmed to have double bonds at carbons
C-8 through C-16. The pair of trans octadecenoic acid positional isomers with double bonds at C-13 and C-14 are reported for the first time to be resolved by
gas chromatography.
This work was presented in part at the 87th American Oil Chemists’ Society Annual Meeting in Indianapolis, IN, April 28–May
1, 1996. 相似文献
2.
Positional and geometrical isomers of monounsaturated long chain fatty acids were analyzed by the combination of high performance
liquid chromatography (HPLC) and glass capillary gas chromatography (GC). A preparative group separation ofcis andtrans isomers of the monounsaturated fatty acid methyl esters was achieved according to chain length by reversed-phase HPLC, and
using a highly sensitive interference refractive index detector. After collection of the different fractions containingcis andtrans forms of the monounsaturated fatty acid methyl esters, the fractions were analyzed for their content of positional isomers
using glass capillary GC with Silar-5 CP as stationary phase. The preparative step in the HPLC was also used analytically
for the determination of the ratio between thecis andtrans monounsaturated fatty acids. A comparison was made between the results obtained with the HPLC technique and the results of
a GLC technique with a packed OV-275 column. There was a good correlation between the 2 techniques with a tendency to highertrans values with the HPLC technique (4%). It was shown with reference substances that 18∶1ω6-cis to ω11-cis and 18∶1ω5-trans to ω12-trans, the most common monounsaturated fatty acid isomers in partially hydrogenated vegetable oils, could be almost quantitatively
recovered in the HPLC step. Most of the individual positional isomers of monounsaturated fatty acids of varying chain length
could be separated and determined in the glass capillary GC step with the exception of those isomers containing the double
bond in a relatively high ω-position. The relative standard deviation of the technique as determined with reference substances
was better than 4%. The described technique was applied to the analysis of the isomeric monounsaturated fatty acid content
in partially hydrogenated vegetable and marine oils, and about 5 samples a day could be executed.
Part of this work has been presented at the ISF/AOCS World Congress, New York (1980)JAOCS 58, (4), 1981, abstr. no. 184. 相似文献
3.
The percentage distribution of the geometrical and positional isomers in the hexadecenoates and octadecenoates isolated from
triglycerides, phosphatidylch olines, and phosphatidylethanolamines of brain, heart, kidney, liver, lung, muscle, spleen,
and adipose tissues from normal rats maintained on a laboratory diet has been determined. All of the octadecenoates and most
of the hexadecenoates from the lipid classes of all the tissues consisted of more than 95%cis isomers. Generally, palmitoleic was the predominant hexadecenoate, but many of the tissue phospholipids contained relatively
high percentages of the Δ6 and Δ7 isomers. Oleate and vaccenate were the predominant octadecenoates in all tissues. Except
for brain and adipose tissues, the oleate to vaccenate ratios differed for each lipid class, as well as between most tissues.
In contrast to the monoenes of the phospholipids, the triglyceride monoenes exhibited the same approximate: percentage composition;
percentage of geometrical isomers; and percentage distribution of hexadecenoate and octadecenoate positional isomers. These
data add to our basic information about the percentage distribution of geometrical and positional isomers of naturally occurring
unsaturated fatty acids in the major lipid classes of various normal tissues. Some new concepts were advanced as possible
explanations to some of the observed positional isomer distributions. 相似文献
4.
C. R. Scholfield V. L. Da Vison H. J. Dutton 《Journal of the American Oil Chemists' Society》1967,44(11):648-651
A liquid Chromatographic procedure for frac-tionation and analysis of methyl esters from fats is described. First, esters
are separated by liquid chromatography on a partially vulcanized rubber column into trienoate, dienoate, monoenoate-palmitate
and stearate fractions. The monoenoate-palmitate fraction is separated by liquid chro-matography on a silver-saturated cation
exchange resin into palmitate,trans monoenoate and cis monoenoate fractions. Double bond positions intrans and cis monoenoates are located by ozoniza-tion and gas chromatography of fragments. This separation procedure requires less
time and uses simpler apparatus with smaller samples than a previously described method based on counter-current distribution.
Data from analyses of two liquid oils and four shortenings are presented.
No. Utiliz. Ees. Dev. Div., ARS, USDA. 相似文献
5.
Selim M. Erhan Robert Kleiman Terry A. Isbell 《Journal of the American Oil Chemists' Society》1993,70(5):461-465
The formation of estolides was detected during the studies on dimerization of meadowfoam oil fatty acids. By adjusting the
reaction conditions, it was possible to produce monoestolides with little dimer or trimer formations. Estolides have potential
use in lubricant, cosmetic and ink formulations and in plasticizers. This paper reports the conditions for production of estolides
from mixed meadow-foam fatty acids, commercial oleic acid, high-oleic sun-flower oil fatty acids,cis-5,cis-13-docosadienoic acid, petroselinic acid and linoleic acid. 相似文献
6.
Mono- and polyestolides, made from oleic acid, meadowfoam oil fatty acids and erucic acid, were subjected to biodegradation
with mixed cultures of Penicillium verucosum, Mucor racemosus, and Enterobacter aerogenes. Fermentations were continued for 3, 5, 10, 15, 20, or 30 d. Meadowfoam oil and its fatty acids, oleic acid and soybean oil
were also biodegraded under the same conditions. After 10 d, oleic acid and soybean oil were degraded 99.8 and 99.2%, respectively;
meadowfoam oil and its fatty acids were degraded 89.0 and 97.7%, respectively. After 30 d, oleic acid-derived poly- and monoestolides
were degraded 98.6 and 90.0%, respectively, meadowfoam estolides were degraded 75.7%, and erucic acid estolides were degraded
84.0%. 相似文献
7.
R. A. Stein 《Journal of the American Oil Chemists' Society》1965,42(4):326-329
The methods for determining the positions of unsaturation in fatty acids are reviewed. Overoxidation and isolation problems
germane to permanganate oxidations, and the formation of by-products and attack of solvents during ozonolysis are considered.
The applicability of mass, nuclear magnetic and infrared spectral data to the problem of locating positions of unsaturation
is discussed. 相似文献
8.
A range ofcis- andtrans-monoenoic fatty acids was tested as substrates for desaturation in microsomal preparations from rat liver.Trans-monoenoic acids were generally desaturated in the Δ9 position to the same extent as stearic acid. Acids with Δ7-trans- and Δ11-trans-olefinic unsaturation produced Δ7-trans,9-cis- and Δ9-cis,11-trans-conjugated dienoic acids, respectively, but the Δ8-trans- and Δ10-trans-monoenoic acids did not give Δ8,9- or Δ9,10-allenes. Of thecis-monoenoic acids examined, only those with double bonds at or beyond the Δ14 position gave any measurable Δ9 desaturation.
When Δ9 desaturation of long chain saturated acids was inhibited by adding sterculic acid, these saturated acids were desaturated
at the Δ5 and Δ6 positions. Many of the monoenoic acids tested were also desaturated at the Δ5 and/or Δ6 positions, although
the percentage conversions were always low. Δ9-cis,11-trans-, Δ9-cis,12-trans- and Δ9-cis,13-trans-dienoic acids, produced in situ by Δ9 desaturation of the corresponding monoenoic acids, were extensively desaturated in
the Δ6 position. These results are discussed in terms of: (a) the various models proposed to explain the substrate specificities
of the desaturases, and (b) the metabolism of unnatural fatty acids ingested from dietary sources. 相似文献
9.
10.
Gas-liquid chromatography (GLC) and thin-layer chromatography (TLC) were used to investigate the isomeric positional geometrical
isopropylidene derivatives of nine isomeric dihydroxy esters, four isomeric methyl 9,10-12-trihydroxystearates, and eight
isomeric methyl 9,10-12,13-tetrahydroxystearates prepared from unsaturated fatty acids. The isopropylidenes derived fromcis andtrans monounsaturated fatty acids were easily separated on both polar and nonpolar columns. Positional isopropylidenes derived
from positional isomers of monounsaturated fatty acids were not separated on either liquid phase but were resolved by TLC.
Four of the eight isomeric isopropylidenes derived from the four geometrical isomers of linoleic acid were resolved on the
polar column; the other four isomers eluted as a single peak. The four isomeric isopropylidene-trifluoroacetate derivatives
derived from ricinoleic and ricinelaidic acids were also resolved on the polar column. GLC analyses were carried out with
liquid phases of ethylene glycol succinate methyl silicone polymer (EGSS-X) and methyl silicone polymer (SE-30) packed columns.
Isopropylidenes, in addition to their applicability for the resolution of polyhydroxy acid mixtures, are particularly useful
for the determination of double bond positions and geometrical configurations of fatty acids without cleavage.
Under contract with the U. S. Atomic Energy Commission. 相似文献
11.
12.
Isolation and characterization of the monounsaturated long chain fatty acids ofMycobacterium tuberculosis 总被引:2,自引:0,他引:2
The positions of double bond in the monounsaturated C15−C32 fatty acids ofMycobacterium tuberculosis H37Ra were established by gas chromatography/mass spectrometry of the ozonized esters and their pyrrolidide derivatives.
The monounsaturated C15−C21 fatty acids had the double bond primarily at the Δ9 position while the monounsaturated longer chain fatty acids (C22−C32) had the double bond in several positions. Many of the latter acids, especially the odd-numbered series, were very complex
isomeric mixtures. Quantitation showed the most abundant even-numbered long chain fatty acid isomers to be as follow: C22, Δ4; C24, Δ5; C26, Δ7 and Δ9; C28, Δ9; C30, Δ11 and Δ13; C32, Δ13 and Δ15. 相似文献
13.
Kohei Yamamoto Akira Shibahara Akiko Sakuma Takao Nakayama Goro Kajimoto 《Lipids》1990,25(10):602-605
The pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis-monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such
as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The
main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic
(cis-9-hexadecenoic) acid andcis-vaccenic (cis-11-octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube
fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance
of n−5 monoenoic acid isomers. 相似文献
14.
X-Ray powder diffraction patterns of the sodium soaps of 14 monounsaturated and polyunsaturated fatty acids were obtained
at room temperature. The patterns of the soaps of 9,12-trans,trans-octadecadienoic acid, 11,14-cis,cis-eicosadienoic acid 11,14,17-allcis-eicosatrienoic acid and 5 monounsaturated fatty acids were typical of the crystalline lamellar phase. The patterns of the
soaps of 9,12-cis,cis-octadecadienoic, allcis-9,12,15-octadecatrienoic, allcis-8,11,14-eicostrienoic, allcis-5,8,11,14-eicosatetraenoic, allcis-5,8,11,14,17-eicosapentaenoic and allcis-4,7,10,13,16,19-docosahexaenoic acids were indicative of the less ordered forms reported for sodium oleate at elevated temperature.
The diffraction data from the less ordered soaps are consistent with the melted form of the hydrocarbon chains of the unsaturated
acids at room temperature. 相似文献
15.
Conclusions Periodate-permanganate oxidation of three samples of oleic acid considered to be of high purity has given reproducible but
less than theoretical amounts of total dibasic acids. Recovery approximated 92% with about 90.3% of the expected azelaic acid.
Recovery of other dibasic acids indicated that about 1.5% of the total unsaturation of these samples of oleic acid was present
in positions 8 or 10 in the fatty acid molecule.
Oxidation of elaidic acid produced from one of the oleic acids has given total dibasic acid yield of about 96%, with a smaller
amount of its total unsaturation in the same position as in the parent oleic acid.
Oxidation of high purity 9,10-dihydroxystearic acid has given essentially quantitative yield of total dibasic acids. The method
described should be useful in determining the composition of similar unsaturated positional isomers.
Controls showing the effect of the method on azelaic acid and on a mixture of azelaic acid with pelargonic have shown essentially
quantitative recovery of azelaic acid. Failure to establish quantitative recovery on oxidation of oleic acid must be caused
by some unknown factor during oxidationper se. The experimental technique described was satisfactory for quantitative studies of the type undertaken.
Oxidation of moderate-purity, mono-unsaturated fatty acids, such as erucic, 10-undecenoic, and vaccenic acid, has given mixed
dibasic acids corresponding to the respective positions of unsaturation.
The data indicate that the method described shows the position of minor unsaturation within about 1%.
Presented at meeting of American Oil Chemists' Society, Chicago, Ill., September 24–26, 1956. 相似文献
16.
S. Kermasha S. Kubow M. Safari A. Reid 《Journal of the American Oil Chemists' Society》1993,70(2):169-173
Triacylglycerol (TAG) standards were separated by analytical high-performance liquid chromatography (HPLC) with laser light-scattering
detection (LLSD). A high sensitivity for TAGs was observed with LLSD whereas poor sensitivity was observed with ultraviolet
detection. The HPLC-LLSD analytical separation of butterfat TAGs showed that the TAGs were eluted according to increasing
carbon number. Preparative HPLC-LLSD was used to characterize butterfat TAGs that contained hypercholesterolemic fatty acids
(laurate, myristate, palmitate) with carbon chainlengths of 12 or greater. These TAG fractions accounted for 29.2% of the
total butterfat TAGs. Analysis of the positional distribution of fatty acids of selected butterfat TAGs containing hypercholesterolemic
fatty acids showed the presence of positional isomers in each of these fractions. These butterfat TAGs also showed the predominant
presence of hypercholesterolemic fatty acids at thesn-2 position. The characterization of the positional distribution of hypercholesterolemic fatty acids in butterfat TAGs is
the first step for the determination of the metabolic role of the positional distribution in the hypercholesterolemic effects
of butter. 相似文献
17.
The fatty acids of liver lipids from rats raised on a fat free diet from the 30th to the 90th day after birth were analyzed
with special regard to the detection of positional isomers of mono-, di-, tri-, and tetraenoic fatty acids. The methyl esters
obtained after transesterification of total lipids were separated by argentation chromatography into five fractions: I saturated,
II monoenoic, III dienoic, IV dienoic nonmethylene interrupted, V triand tetraenoic fatty acid esters. After hydroxylation
of the double bonds with osmium tetroxide, the analysis of the poly-O-trimethylsilyl derivatives by gas liquid chromatography
on S.C.O.T. columns combined with mass spectrometry revealed the presence of 19 monoenoic, 15 dienoic, and 9 trienoic as well
as 3 tetraenoic fatty acid isomers including the normally occurring representatives of the (n−3), (n−6), (n−7), and (n−9)
fatty acid families. The majority of the identified isomers can be coordinated to one of these families like 7–16∶1; 11–20∶1;
6,9–18∶2; 8,11–20∶2; 5,11–20∶2; 5,8,11–20∶3; 7,10,13–22∶3 to the (n−9) family, 11–18∶1; 13–20∶1; 5,11–18∶2; 7,13–20∶2; 6,11–18∶2;
6,9–16∶2; 8, 11–18∶2; 10,13–20∶2; 5,8,11–18∶3; 7,10,13–20∶3; 4,7,10,13–20∶4 to the (n−7) family and 11,14–20∶2; 5,11,14–20∶3;
6,9,12–18∶3; 8,11,14–20∶3; 5,8,11,14–20∶4; 7,10,13,16–22∶4 to the (n−6) family. All these naturally occuring isomers can be
placed into a network of desaturation and chain elongation steps which allows certain conclusions about the substrate specificity
of the Δ6-, Δ5-and Δ4-desaturase systems. The great number of isomers found in the (n−7) family indicates that the members
of this family are actively metabolized in partial essential fatty acid deficiency. 相似文献
18.
Mehmet etin Ayhan Yldrm A. Metin ahin 《European Journal of Lipid Science and Technology》2003,105(11):683-687
The fatty acid composition and total trans fatty acid content in 10 margarines produced in Turkey were determined by capillary gas chromatography and Fourier transform‐infrared spectroscopy (FT‐IR) spectroscopy. The fatty acid composition ranged as follows: saturated fatty acids, C16:0 (palmitic) 11.3 to 31.8% and C18:0 (stearic) 5.7 to 8.7%, monounsaturated fatty acids, C18:1 (oleic) 21.8 to 35.7% and C18:1 trans isomers 0.4 to 27.4%, polyunsaturated fatty acid, C18:2 linoleic acid 5.2 to 40.2%. Some positional isomers of C18:1 as cis‐11‐octadecenoic acid varied from 0.7 to 4.6% and cis‐13 trace to 2.4%. The total trans fatty acid contents were between 0.9 and 32.0% when measured with capillary gas chromatography and between 0 and 30.2% with FT‐IR spectroscopy. Some of the margarines analyzed contained trace amount of trans fatty acids which could not be detected by FT‐IR spectroscopy. 相似文献
19.
20.
多不饱和脂肪酸因其在食品和医药领域的广泛作用而得到人们极大的关注,当前利用微生物发酵生产多 不饱和脂肪酸具有诸多优点,由于酵母生产迅速且生物量较高,利用酵母生产多不饱和脂肪酸已成为人们关注 的热点。本文综述了代谢工程改造酵母生产多不饱和脂肪酸的研究进展,以常规酵母-酿酒酵母和非常规酵母- 解脂耶氏酵母为例,介绍了酵母菌中多不饱和脂肪酸的代谢途径、酵母产油脂的生化机制、代谢工程改造酵母 产多不饱和脂肪酸以及不饱和脂肪酸积累对酵母耐受性的影响。以后研究工作的重点是进一步加强对酵母生产 多不饱和脂肪酸的机理研究,并以此为来指导代谢工程改造酵母生产多不饱和脂肪酸。 相似文献