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1.
Gayland F. Spencer Ronald D. Plattner Thomas Miwa 《Journal of the American Oil Chemists' Society》1977,54(5):187-189
Two analytical procedures for determining com-positions of jojoba liquid wax esters are described and compared. One, the more
tedious, involves separation of wax ester homologs by high pressure liquid chro-matography followed by determination of the
acid and alcohol moieties from each homolog. The second allows rapid determination of wax ester composition by gas Chromatographic
separation of hydrogenated jojoba wax esters according to chain length, followed immediately by ancillary mass spectrometric
identifi-cation of the acid and alcohol moieties. Double bonds in the alkyl chains in jojoba liquid waxes were almost exclusively
(98%) ω-9, when examined by gas chro-matography/mass spectrometry (GC/MS) and ozonolysis/GC/MS.
Presented in part at the 2nd International Conference on Jojoba and Its Uses, Ensenada, Mexico, February, 1976. 相似文献
2.
Thomas K. Miwa 《Journal of the American Oil Chemists' Society》1971,48(6):259-264
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. 相似文献
3.
David J. Sessa Terry C. Nelsen Robert Kleiman James D. Arquette 《Journal of the American Oil Chemists' Society》1996,73(2):271-273
Differential scanning calorimetry (DSC) thermograms of fatty esters can give valuable information on melting characteristics
and heats-of-fusion enthalpy (ΔH). A series of jojoba liquid wax esters was constructed by transesterifying native jojoba
oil with 5–50% completely hydrogenated jojoba wax esters. This series, when subjected to a standardized DSC tempering method
with heating/cooling cycles, exhibited an excellent correlation for level of saturation based on area changes in endothermic
ΔH. Endothermic events were recorded for native (ΔHA) and completely hydrogenated (ΔHC) jojoba wax esters. A third endotherm, ΔHB, was observed when they were transesterified. Based on a multiple regression program, the best fit (R2=0.98) using ΔH data was: % saturation=16.847–0.162 (ΔHA)+0.209 (ΔHB)+0.600 (ΔHC). Standard errors for predictions were approximately 1.045 at 0% saturation, 0.770 at 25% saturation, and 1.158 at 50% saturation.
Endothermic events A, B, and C each represent the respective diunsaturated, mounounsaturated, and saturated contents of wax
esters in the transesterified blends. This was verified by measuring the dropping points for both the native and completely
hydrogenated wax esters. These findings provide an index which can predict the degree of saturation in transesterified wax
ester blends and serves as a research tool in process and product developments.
Presented at the 1995 AOCS Meeting, May 7–11, 1995, San Antonio, Texas.
Retired. 相似文献
4.
Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal
sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/1H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols
in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C14 to C22. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol
were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing
30% of the total fatty acids. The alcohols of wax ester were all saturated with C20–C29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl
glycerol ethers. 相似文献
5.
Trans-6-hexadecenoic acid was found in polar lipids, triglycerides, was esters and diacylglyceryl ethers of the sea anemoneMetridium dianthus from Passamaquoddy Bay. The corresponding alcomaquoddy Bay. The corresponding alcohol also apparently occurs in the wax esters
of this species. The long-chain (C20, C22) monoethylenic alcohols reported for other species of sea anemones from neighboring waters were absent and the major alcohol
and glyceryl ether chain both had 16∶0 structures. The isomers of C18 and C20 monoethylenic fatty acids in polar lipids and triglycerides were unusual in their high proportion of theω
7 isomer. These two lipids also contained higher proportion of the polyunsaturated fatty acids than the others. 相似文献
6.
The intact preen wax esters of the red knot Calidris canutus were studied with gas chromatography/mass spectrometry (GC/MS) and GC/MS/MS. In this latter technique, transitions from the
molecular ion to fragment ions representing the fatty acid moiety of the wax esters were measured, providing additional resolution
to the analysis of wax esters. The C21−C32 wax esters are composed of complex mixtures of hundreds of individual isomers. The odd carbon-numbered wax esters are predominantly
composed of even carbon-numbered n-alcohols (C14, C16, and C18) esterified predominantly with odd carbon-numbered 2-methyl fatty acids (C7, C9, C11, and C13), resulting in relatively simple distributions. The even carbon-numbered wax esters show a far more complex distribution
due to a number of factors: (i) Their n-alcohol moieties are not dominated by even carbon-numbered n-alcohol moieties are not dominated by even carbon-numbered n-alcohols esterified with odd carbon-numbered 2-methyl fatty acids, but odd and even carbon-numbered n-alcohols participate in approximately equal amounts; (ii) odd carbon-numbered methyl-branched alcohols participate abundantly
in these wax ester clusters; and (iii) with increasing molecular weight, various isomers of the 2,6-, 2,8-, and 2,10-dimethyl
branched fatty acids also participate in the even carbon-numbered wax esters. The data demonstrate that there is a clear biosynthetic
control on the wax ester composition although the reasons for the complex chemistry of the waxes are not yet understood. 相似文献
7.
In addition to the ω-5 olefinic acids found in otherGrevillea species, about 10% of the acyl groups ofG. decora seed oil contain a hydroxy group and an ω-5 double bond. The chainlengths of these acids are from C22 to C30, with the largest concentration at the C26 and C28 chainlengths. The hydroxy group is located on odd carbons from carbon-5 through carbon-13. These acids previously were unknown
in nature. The most abundant of these are 7-hydroxy-cis-17-docosenoic, 7-hydroxy-cis-19-tetracosenoic, 9-hydroxy-cis-19-tetracosenoic, 9-hydroxy-cis-21-hexacosenoic, 11-hydroxy-cis-21-hexacosenoic, and 13-hydroxy-cis-23-octacosenoic acids. The oil also contains the largest known concentration of the unoxygenated C26 and C28 ω-5 monoenes. 相似文献
8.
Limanathes douglasii seed oil glycerides contain fatty acids which predominantly (97%) have 20 or more carbon atoms. Fatty acids were prepared
by saponification; fatty alcohols, by sodium reduction of the glycerides; and liquid wax esters, byp-toluenesulfonic acid-catalyzed reaction of the fatty acids with the fatty alcohols. Solid waxes were prepared by hydrogenation
of the glyceride oil and of the wax esters. Chemical and physical constants were determined forLimnanthes douglasii seed oil and its derivatives. The liquid wax esters had properties very similar to those of jojoba (Simmondsia chinensis) seed oil. The solid hydrogenated wax ester was identical in physical appearance and melting point to hydrogenated jojoba
seed oil.
A laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, USDA. 相似文献
9.
Acyl-CoA: alcohol transacylase activity was demonstrated in cell-free homogenates of developing jojoba seeds. The optimal
pH was 8.0–8.1. Under optimal conditions, wax formation had a nearly linear relationship with extract concentration; the time
course of wax formation was also linear up to 30 min.cis-11-Eicosenol was the most effective alcohol substrate whereas tetradecanol, octadecanol, dodecanol,cis-9-octadecanol, andcis-13-eicosenol gave progressively lower activities. Either saturated or unsaturated acyl-CoA with 18 or 20 C-atoms had similar
activity. The enzyme was fairly stable at 0 C, less stable at RT and labile above 30 C. Differential centrifugation showed
that the 12,000 × g fat pad was the most active in wax formation; to maximize the activity, a 12,000 × g supernatant appeared
to be necessary. This factor in the supermatant was thermolabile and nondialyzable. 相似文献
10.
K. Sato J. Yano I. Kawada M. Kawano F. Kaneko M. Suzuki 《Journal of the American Oil Chemists' Society》1997,74(9):1153-1159
Molecular properties of polymorphic forms of gondoic acid [cis-C20:1Δ11ω9 (GOA)] have been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), optical microscopy, and
Raman scattering, in comparison to those of six principal unsaturated fatty acids: oleic acid [cis-C18:1Δ9ω9 (OA)], erucic acid [cis-C22:1Δ13ω9 (ERA)], petroselinic acid [cis-C18:1Δ6ω12 (PSA)], asclepic acid [cis-C18:1Δ11ω7 (APA)], palmitoleic acid [cis-C16:1Δ9ω7 (POA)], and elaidic acid [trans-C18:1Δ9ω9 (ELA)]. In addition, phase behavior of binary mixtures of GOA and APA and OA was examined by XRD and DSC. The polymorphic
structures of GOA are quite similar to those of APA, ERA, POA, and partly to OA. In particular, DSC and Raman scattering studies
have shown that gondoic acid exhibits conformational disordering on heating at the ω-chain, a chain segment between the double
bond and CH3 group, as a transition from all-trans (γ form) to gauche-rich (α form) conformations. A miscible mixing phase was observed in the mixture of GOA and APA, yet eutectic phases were
observed in the GOA and OA mixtures. This is a remarkable contrast because the binary mixture systems of varying combinations
of cis-unsaturated fatty acids examined so far exhibited either eutectic nature or molecular compound formation. It is expected
that specific molecular interactions between GOA and APA that originate from the equivalence of the length of the Δ-chain,
the chain segment between the cis-double bond and COOH group, and also from the presence of the γ-α order-disorder transformation would be operating to form
the miscible mixing phase. 相似文献
11.
Hiroshi Kawashima Eiji Sakuradani Nozomu Kamada Kengo Akimoto Kyoko Konishi Jun Ogawa Sakayu Shimizu 《Journal of the American Oil Chemists' Society》1998,75(11):1495-1500
A Δ5 and Δ12 desaturase-defective mutant of an arachidonic acid-producing fungus, Mortierella alpina 1S-4, produced 8,11,14,17-cis-eicosatetraenoic acid (20:4ω3) intracellularly when grown with linseed oil. Dihomo-γ-linolenic acid was the only C20 polyunsaturated fatty acid (4.9 wt% of total mycelial fatty acids) other than 20:4ω3. AA and 5,8,11,14,17-cis-eicosapentaenoic acid were not detected. The mycelial lipids consisted of 82.2% (by mol) triacylglycerol (TG), 7.1% diacylglycerol,
8.9% phospholipids (PL), and 1.9% free fatty acids. The percentage of 20:4ω3 was higher in PL (30.1%) than in TG (11.6%),
and highest in phosphatidylcholine (38.9%). Under the optimal conditions with a 5-L jar fermenter, 20:4ω3 production amounted
to 97.4 mg/g dry mycelia with a mycelial yield of 23 g/L on the twelfth day (corresponding to 2.24 g/L medium and 37.1% of
total mycelial fatty acids). 相似文献
12.
The fatty acid composition of partially hydrogenated arachis (HAO), partially hydrogenated soybean (HSO) and partially hydrogenated
herring (HHO) oils and of a normal, refined arachis oil (AO) was studied in detail by means of direct gas liquid chromatography,
ultraviolet and infrared spectrophotometry and by thin layer chromatography fractionation on silver nitrate-silica gel plates
followed by gas liquid chromatography. It was shown that the partially hydrogenated oils all contained fatty acids withtrans double bonds. In the plant oils, thetrans acids were present mainly as elaidic acid. The HHO showed an almost equal distribution betweentrans 18∶1 ω9,trans 20∶1 ω>9 andtrans 22∶1 ω>9. Sometrans configuration was also found in the C20-and C22-dienes and trienes of the HHO. In all the oils, conjugated fatty acids were present in minor amounts only (<0.5%). Special
attention was given to the ω-acids known to be of specific nutritional value. The HSO contained about 32% linoleic acid, whereas
the content ofcis, trans+trans, cis andtrans, trans octadecadienoic isomers was 1.7% and 0.5%, respectively. The amount of linoleic acid in the HSO was even higher than that
of AO (29%). The HAO contained only 0.8% 18∶2 ω6 (linoleic acid). Further, two 18∶2 fatty acids with ω>6, acis, cis and atrans, trans isomer, were present in small amounts. The HHO contained 0.5% 18∶2 ω6 (linoleic acid). Isomers of 18∶2 ω>6 were also found
in the HHO. They may be hydrogenation products of higher unsaturated C18-acids orginally present. All the C20- and C22-dienes and trienes were shown to have an ω-chain greater than 6. Fatty acids with ω6-structure were not formed during partial
hydrogenation of the oils studied. 相似文献
13.
Methyl U-14C oleate was fed to mature male and female gouramis (Trichogaster cosby) and the radioactivity in lipids measured over a period of four months. Initial incorporations were 70–80% and more than
half of that was still in the lipids at the end of the experiment. Very little conversion of the 18∶1 chain had occurred.
Main storage of the labeled 18∶1 chain was in the wax esters of the roe and in the triglycerides of the body. In the wax esters,
18∶1 occurred in both the alcohol and acid moieties. Initially the females had less radioactivity in the triglycerides than
in the wax esters but at the end of the experiment this was reversed. An appreciable amount of 18∶1 had been transferred from
roe to body lipids. The biological half life of 18∶1 in gouramis is estimated to be about four months. This time is equal
for males and females although translocation from roe to body and transformation of wax ester to triglyceride take place in
the female, whereas wax esters do not play any role in the lipid metabolism of the male. 相似文献
14.
Isolated bovine meibomian glands incorporated exogenous [1-14C] acetate into lipids. Thin layer chromatographic analysis of the lipids showed that wax esters and sterol esters contained
61% of the total label. Radio gas liquid chromatographic analysis of the acid and alcohol moieties of both ester fractions
showed the label was distributed equally between the two portions of the ester in both cases. Cholesterol and 5-α-cholest-7-en-3β-ol
were the major labeled sterols, and anteiso-C25, anteiso-C27 and anteiso-C23 were the most highly labeled alcohols. The major
labeled fatty acids in the wax esters were anteiso-C15,n-C16, anteiso-C17 andn-C18∶1, whereas anteiso-C25 and anteiso-C27 were the major labeled acids in the sterol esters. The diester region with 6%
of the total label contained labeled fatty acids and fatty alcohols each with anteiso-C25 as the major component and ω-hydroxy
acids in whichn-C32∶1 was the major labeled component. The trigly ceride fraction which contained 8% of the total lipids was composed of
labeled fatty acids similar to those found in both sterol and wax ester fractions. Chromatographic analyses of the labeled
lipids derived from exogenous labeled isoleucine showed that anteiso-branched products were preferentially labeled. The labeled
triglyceride fraction derived from [U-14C] isoleucine also contained esterified C15, C13, C11, C9, C7 and possibly shorter anteisobranched acids. 相似文献
15.
The objective of this study was to determine the effects of genotype and environment on wax composition in jojoba seed, and
thus be able to control it. Production of waxes with different compositions—and hence changed wax properties such as viscosity,
boiling point, and thermal stability—may be of importance for future requirements of the jojoba industry. Wax composition
of 23 female clones was determined for two growing seasons. The ratio of FA elongated to the sum of those reduced and esterified
differed among genotypes, resulting in differences in the percentage of wax esters longer than 40 or 42 carbons. The clones
‘Yarden,’ ‘Gvati’, ‘Hazerim,’ ‘BGU,’ and ‘Negev’ had higher percentages of long-chain wax moieties than the clones ‘879–154’,
‘MS 55–4’, and ‘Forti.’ The contribution of the male genotype to wax composition was tested by pollinating bagged female flowers
of four female clones with pollen from three male plants. Both male and female genotypes additively influenced the composition
of the wax esters. Wax composition varied between growing seasons and locations, but differences between genotypes were consistent.
Salinity of the irrigation water did affect wax composition in some clones. Under high salinity, the salt-sensitive clone
‘64’ produced a smaller percentage of long-chain wax esters, whereas in clone ‘Q-106’ wax composition did not change. In clone
‘874–154’ the chain lengths of the wax moieties in the seeds increased under medium salinity. We conclude that jojoba wax
composition is influenced by both female and male genotypes and by environmental factors such as climate and salinity. 相似文献
16.
L. J. Molaison R. T. O'Connor J. J. Spadaro 《Journal of the American Oil Chemists' Society》1959,36(9):379-382
Summary Jojoba oil is a liquid wax composed essentially of C20 and C22 straight-chain monoethylenic acids and alcohols in the form of esters. Sodium reduction of the wax fatty esters in jojoba
oil yielded quantitatively a mixture of unsaturated, long-chain alcohols from the acid moiety of the jojoba oil. Yields of
about 91% were obtained in the laboratory-scale experiments and 82 to 86 for the pilot-plant experiments. Analytical data,
including detailed infrared spectra information, are given for the resulting product alcohols.
Presented at the fall meeting, American Oil Chemists' Society, Cincinnati, O., September 29-October 2, 1957.
One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S.
Department of Agriculture. 相似文献
17.
The effects of the mixedcis- 18∶1 isomers and mixedtrans-18∶1 isomers present in partially hydrogenated soybean oil (PHSO) upon the patterns of polyunsaturated fatty acids (PUFA)
in liver phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were studied in rats fed concentrates ofcis- 18∶1 ortrans- 18∶1 isomers isolated as triacylglycerides from PHSO. Thecis- 18∶1 andtrans- 18∶1 concentrates were fed at levels equal to those present in PHSO fed at 17.9% of the diet. All diets contained the required
amounts of both linoleic and linolenic acids. Thetrans- 18∶1 concentrate was found to suppress the levels of 20∶4ω6 and 20∶3ω9, and to increase the levels of 18∶2ω6 and 20∶5ω3
in PC and PE. Thecis- 18∶1 concentrate suppressed 20∶4ω6 in PC, 20∶5ω3 in PC and PE, and 18∶2ω6 was more effective than thetrans concentrate in suppressing 22∶6ω3. Thetrans- 18∶1 concentrate was more effective in suppressing 20∶4ω6. Thetrans-18∶ isomers appear to modify PUFA metabolism by inhibition of PUFA synthesis, whereas thecis- 18∶1isomers appear to compete with 2-position fatty acyl transfer and to inhibit ω3 PUFA acylation. 相似文献
18.
A number of minor unsaturated fatty acids of rapeseed oil (fromBrassica napus orcampestris) have been isolated by combinations of distillation preparatve gas liquid chromatography and silver nitrate thin layer chromatography,
and were further identified by oxidative fission in BF3-MeOH. Among the shorter chain, all-cis polyunsaturated fatty acids described are 16:3ω3, 16:2ω6 and 14:2ω6. A ubiquitous minor component inunproceessed oils was found to becis-9, cis-12, trans-15-octadecatrienoic acid, with lesser proportions of thetrans-9, cis-12, cis-15 isomer. Among others identified werecis-14:1ω9 and 15:1ω10, the latter accompanied by half as muchtrans-15:1ω10. Particular attention was paid to the proportions of the minor monoethylenic fatty acids of the ω7 series relative
to the longer chain major ω9 monoethylenic fatty acids which have been reduced by plant breeding. 相似文献
19.
Chemical structure of long-chain esters from “sansa” olive oil 总被引:1,自引:0,他引:1
Giorgio Bianchi Aldo Tava Giovanna Vlahov Nicoletta Pozzi 《Journal of the American Oil Chemists' Society》1994,71(4):365-369
The major objective of this study was to determine the chemical structure of long-chain esters present in lower-grade olive
oil. The classes of esters composing the hexanediethyl ether (99∶1) extract of the wax fraction from a pomace olive oil were:
(i) esters of oleic acid with C1−C6 alcohols, (ii) esters of oleic acid with long-chain aliphatic alcohols in the range C22−C28 and (iii) benzyl alcohol esters of the very long-chain saturated fatty acids C26 and C28. The analysis and the structure assignments were carried out by gas chromatography coupled with mass spectrometry and by
comparison with synthetic authentic model compounds. This work provided precise data on the chemical nature of the wax esters
present in olive oil and should represent a means to detect adulteration of higher-grade olive oil with less expensive pomace
olive oil and seed oils. 相似文献
20.
Jojoba wax and its derivatives are slow-reacting compounds. To elucidate the reasons for this phenomenon, we reacted jojoba
mono- and bis-epoxide and trans-jojoba bis-epoxide (C38–C44 long-chain esters), as well as side chain esters of three steroid skeleton mono-epoxide derivatives with NaI under acidic
conditions to yield the corresponding iodohydrins, which then formed the respective bis-keto (or mono-ketone) derivatives.
The kinetics, activation energies, and thermodynamic parameters of activation of nucleophilic epoxide opening and pinacol
rearrangement were determined for all these compounds. The reaction rates of the jojoba derivatives were similar to those
of two of the epoxides derived from the steroid skeleton compounds, and in the third case the steroid derivative reacted somewhat
faster than all the rest. This pattern of rate retardation could stem either from folding of the long jojoba chain, resulting
in steric hindrance around the reaction centers, or from repeated unproductive collisions along the long hydrocarbon chain
of the jojoba wax (statistical effect). Our results appear to suggest that the multiple unsuccessful collisions were the dominant
factor, although steric hindrance cannot be ruled out. 相似文献