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1.
Sodeif Azadmard-Damirchi Paresh C. Dutta 《Journal of the American Oil Chemists' Society》2007,84(3):297-304
Free and esterified forms of sterols provide detailed information on the identity and the quality of vegetable oils. In this
study, 4,4′-dimethylsterols in free and esterified forms were investigated in hazelnut and virgin olive oils. Moreover, a
sample of solvent-extracted hazelnut oil was refined at the laboratory to monitor the effects of processing on the levels
of 4,4′-dimethylsterols. Generally, the level of total 4,4′-dimethyslterols was higher in the esterified form (49–68%) compared
with that in free form (32–51%) of these compounds in the hazelnut oil. In virgin olive oil samples, cycloartenol and 24-methylenecycloartanol
were present in higher amounts in free forms (70–80%) than in esterified forms (20–30%). Among the refining processes, degumming,
deodorization, neutralization and bleaching, only neutralization and bleaching considerably reduced 4,4′-dimethylsterols.
In fully refined hazelnut oil, 18 and 37% of lupeol and an unknown compound X in the esterified form were lost, respectively.
The loss of these two compounds in the free form was considerably higher, 26 and 72%, respectively. GC–MS analysis showed
that adulteration of olive oil with a sample of fully refined hazelnut oil could be detected at a level as low as 2% by tracing
lupeol in total or only in esterified forms of 4,4′-dimethylsterols. Further studies on the levels of free and esterified
4,4′-dimethylsterols and their retention during refining processes are anticipated in hazelnut cultivars from different origins. 相似文献
2.
Sterols,methylsterols, and triterpene alcohols in threeTheaceae and some other vegetable oils 总被引:4,自引:0,他引:4
The unsaponifiables from threeTheaceae (Camellia japonica L.,Camellia Sasanqua Thunb., andThea sinensis L.) oils and alfalfa, garden balsam, and spinach seed oils and shea fat were separated into four fractions: sterols, 4-methylsterols,
triterpene alcohols, and less polar compounds by thin layer chromatography. While the sterol fraction was the major one for
the unsaponifiables from alfalfa and spinach seed oils, the triterpene alcohol fraction was predominant for the unsaponifiables
from all other oils. The sterol, 4-methylsterol, and triterpene alcohol fractions were analyzed by gas chromatography. All
the sterol fractions were alike in their compositions, consisting exclusively of Δ7-sterols, such as α-spinasterol and Δ7-stigmastenol as predominant components together with Δ7-avenasterol and 24-methylcholest-7-enol. Obtusifoliol, gramisterol (occasionally accompanied with cycloeucalenol), and citrostadienol,
together with several other unidentified components, were found in the 4-methylsterol fractions from all of the oils except
shea fat. The 4-methylsterol fraction from shea fat showed a characteristic composition containing a large proportion of unidentified
components which had relative retention time greater than that of citrostadienol, while no citrostadienol was detected. β-Amyrin,
lupeol, and butyospermol were major components of the triterpene alcohol fractions from most of the oils, but the fraction
from spinach seed oil contained cycloartenol and 24-methylene-cycloartanol as predominant components. There is a close similarity
in the compositions of unsaponifiables (sterols, 4-methylsterols, and triterpene alcohols) of the threeTheaceae oils. Two sterols, α-spinasterol and Δ7-stigmastenol, and five triterpene alcohols were isolated from tea seed oil. Moreover, five unidentified components beside
parkeol, butyrospermol, α-amyrin, and lupeol were isolated from the triterpene alcohol fraction of shea fat. 相似文献
3.
Sterol lipids of cocoa butter (cocoa beansLome Tongo) were fractionated into free sterols, steryl esters (SE), steryl glucosides and acylated steryl glucosides (ASG). 4-Desmethyl,
4-methyl and 4,4′-dimethyl sterols or triterpene alcohols, which were isolated as free sterols or which resulted from hydrolysis,
were determined by thin layer chromatography-flame ionization detection and identified by gas chromatography and combined
gas chromatography-mass spectroscopy. Free sterols comprise the main sterol fraction in cocoa butter. Esterified sterols amount
to 11.5% of total sterols and glucosidic sterols to 16.3%. Fatty acids and D-glucose from hydrolysis of esters and glucosides
were analyzed. The fatty acids of SE and ASG are richer in unsaturated fatty acids than cocoa butter total fatty acids. 相似文献
4.
Reports on the methylsterol fractions of hazelnut oils are scarce. The objectives of this study were to characterize methylsterols
in hazelnut and virgin olive oils and to study the possibility of detection of adulteration of virgin olive oils. In hazelnut
oils, 4-desmethylsterols were present in higher proportions (86 to 91%) than in virgin olive oils where this fraction was
ca. 50% of the total sterol. In the 4-monomethylsterol fraction, citrostadienol was the major component in both kinds of oils
followed by cycloeucalenol and obtusifoliol in virgin olive oils, and obtusifoliol in hazelnut oils. 24-Methylenecycloartanol
was predominant in both kinds of oils in the 4,4′-dimethylsterols. For the first time, δ-amyrin was tentatively identified
by comparing published mass spectral data in the analyzed samples of both kinds of oils. An unknown compound X (containing
a lupane skeleton) and lupeol were detected only in the 4,4′-dimethylsterols fraction of hazelnut oils at a level of 2–8 and
6–10%, respectively. GC-MS analysis showed that adulteration of virgin olive oil by hazelnut oil could be detected at a level
less than 4% by using these two compounds as possible potential markers. 相似文献
5.
Sodeif Azadmard-Damirchi Mahboob Nemati Javad Hesari Masoud Ansarin Bahram Fathi-Achachlouei 《Journal of the American Oil Chemists' Society》2010,87(10):1155-1159
Phytosterols are separated into three classes: 4-desmethylsterols, 4-monomethylsterols and 4,4′-dimethylsterols. 4,4′-Dimethylsterols
are used to detect vegetable oil adulteration and some compounds from this class can have anti-inflammatory and anticancer
properties. There are methods such as thin layer chromatography (TLC) and solid phase extraction (SPE) used to separate phytosterol
classes from each other. However, in some cases, separation of all three classes is not required. In addition, TLC has some
drawbacks such as low recovery and it is time consuming. An SPE method has previously been used, but it was necessary to use
high volume of solvents with this method to avoid coelution of phytosterol classes. In this study, an SPE (silica, 1 g) method
was developed to separate and enrich only 4,4′-dimethylsterols from unsaponifiables of vegetable oil samples using 25 mL n-hexane and diethyl ether (95:5, v:v). This method was applied to hazelnut and olive oils and results were compared with those
of TLC and the previously developed SPE method. Recovery of 4,4′-dimethylsterols was two times higher with the new SPE method
compared with the TLC method. The newly developed SPE method generally gave a similar recovery compared with the previously
developed SPE method. Moreover, the SPE method developed in this study has the advantage of using a 3.5 times lower volume
of solvent than previously developed SPE methods. Because the newly developed SPE method has a single step requiring a low
volume of solvents, it is rapid and simple, and can easily be used to detect olive oil adulteration with hazelnut oil and
to analyze and quantify effective nutritional compounds in the 4,4′-dimethylsterols class. 相似文献
6.
In an attempt to combine the hypocholesterolemic properties of plant sterols with the hypotriglyceridemic action of fish oil
FA, plant sterols have recently been esterified to fish oil n−3 PUFA. The objective of this study was to determine the effects
of plant sterols esterified to n−3 PUFA on plasma lipid levels and erythrocyte fragility. For 5 wk, male Golden Syrian hamsters
were fed diets varying in cholesterol and plant sterol content: (i) Noncholesterol (semipurified diet with no added cholesterol
or plant sterols) (ii), Cholesterol (0.25% cholesterol) (iii), Sterols (0.25% cholesterol plus 1% nonesterified plant sterols),
or (iv) Fish oil esters of plant sterols (0.25% cholesterol plus 1.76% EPA and DHA sterol esters, providing 1% plant sterols).
The addition of fish oil esters of plant sterols to the cholesterol diet decreased (P=0.001) plasma total cholesterol levels by 20%, but nonesterified plant sterols did not have such a beneficial impact. In
addition, non-HDL cholesterol concentrations were 29% lower in hamsters fed fish oil esters of plant sterols than in hamsters
fed nonesterified plant sterols (P<0.0001). Despite higher (P<0.0001) plant sterol levels in whole erythrocytes of hamsters fed nonesterified plant sterols and fish oil esters of plant
sterols compared with hamsters fed no plant sterols, no difference was observed in erythrocyte fragility. The present results
show that EPA and DHA esters of plant sterols have a hypocholesterolemic effect in hamsters, and that these new esters of
plant sterols exert no detrimental effect on erythrocyte fragility. 相似文献
7.
Arange of analytical techniques was used to investigate the composition of the steryl fatty acyl esters in a cell suspension
culture of celery (Apium graveolens). Gas chromatography (GC) and GC-mass spectrometry (GC-MS), using electron ionization (EI) and negative ion chemical ionization
(NICI), were employed to characterize the intact steryl esters. Assignments were supported by analysis of the sterol and fatty
acid moieties released from the intact molecular species by alkaline hydrolysis. A selectivity for sterol esterification was
noted, with the major free sterol, stigmasterol, occurring only in a very small amount in the esterified form. Instead, the
precursors to Δ5-phytosterols, particularly cycloartenol, predominated in the ester fraction. The pentacyclic triterpene, β-amyrin, was also
found as the palmitate and linoleate esters. Changes in composition and abundance of the steryl esters during the different
growth phases of a celery cell suspension culture were investigated. The total amount of esterified sterols exceeded that
of free sterols throughout the growth cycle. The changes observed during growth highlighted differences between the esters
of precursor sterols and those of the 4-desmethyl-sterols, and it is postulated that the various steryl esters perform different
functions in cell metabolism. 相似文献
8.
Béatrice Ramaroson-Raonizafinimanana Emile M. Gaydou Isabelle Bombarda 《Journal of the American Oil Chemists' Society》1998,75(10):1325-1328
Eleven 4-desmethylsterols, four 4,4-dimethylsterols, and twelve 4-methylsterols were identified in Vanilla madagascariensis beans. The 4-desmethylsterol fraction was characterized by a high level of 5α-cholesta-7,24(25)-dien-3β-ol (35.3%). The 4-methylsterol
fraction was characterized by a high level of 31-norcycloartenol (57.5%) and the presence of 23-dehydrolophenol (9.4%). Cycloartenol
(72.9%), cyclosadol (12.7%), parkeol (9.7%), and 24-dehydrotirucallol (4.7%) were identified in the 4,4-dimethylsterol fraction. 相似文献
9.
E. Fedeli A. Lanzani P. Capella G. Jacini 《Journal of the American Oil Chemists' Society》1966,43(4):254-256
Triterpene alcohols and sterols were separated by thin-layer chromatography and gas-liquid chromatography from the unsaponifiable
fractions of the following 18 vegetable oils: linseed, peanut, olive, rice bran, palm kernel, corn, sesame, oiticica, palm,
coconut, rapeseed, grape seed, sunflower, poppy seed, castor, tea seed, cocoa butter and soybean. Two triterpene alcohols,
cycloartenol and 24-methylene cycloartanol, were found in all of the oils except soybean oil, which contained only cycloartenol.
Triterpene alcohols such as α- and β-amyrin, euphorbol, butyrospermol and cyclolaudenol also were encountered occasionally.
Three sterols, β-sitosterol, stigmasterol and campesterol were present in all of the oils. In addition a fourth sterol, not
yet idenfified, was found in oils of palm, palm kernel and sunflower in varying amounts. This unknown sterol and brassicasterol
were found in rapeseed oil in addition to the three sterols that were common to all of the oils studied.
Experiment Station for Fats and Oils, National Center for Lipochemistry of National Research Council, Milan, Italy. 相似文献
10.
Pollen sterols from three species of sonoran cacti 总被引:2,自引:0,他引:2
Cactus bees are important pollinators that contribute to the long-term stability of arid regions in the United States. Since
all insects are dependent upon a dietary source of sterol for normal growth, development and reproduction, a study was undertaken
to determine neutral sterols available to cactus bees. The total neutral sterol composition of hand-collected pollen was determined
for three species of Sonoran cacti by gas-liquid chromatography and mass spectrometry. 24-Methylenecholesterol was the predominant
pollen sterol in Engelmann's prickly pear,Opuntia phaeacantha, cholla,O. versicolor, and cardon,Pachycereus pringlei. Two pentacyclic triterpene alcohols, lupeol and moretenol, were also isolated. Since no cholesterol was detected in any
of the pollen samples, cactus bees would have to utilize the 24-alkyl sterols unchanged or convert these sterols to cholesterolvia dealkylation. 相似文献
11.
To investigate the metabolism and possible deleterious effects of 4-methyl and 4,4-dimethyl steroids inManduca sexta, the 4,4-dimethyl sterols lanosterol and cycloartenol, the 4-methyl sterol obtusifoliol and the 4,4-dimethyl pentacyclic
triterpenoid α-amyrin were fed in an artificial agar-based diet at various concentrations. Utilization and metabolism of these
four compounds were compared with sitosterol, stigmasterol, brassicasterol, ergosterol and 24-methylenecholesterol, 24-alkyl
sterols that are readily dealkylated and converted to cholesterol inManduca and in most phytophagous insects. None of the 4-methylated compounds significantly inhibited development except at very high
dietary concentrations. The Δ24-bonds of lanosterol and cycloartenol were effectively reduced by theManduca Δ24-sterol reductase enzyme, as is the Δ24-bond of desmosterol which, in most phytophagous insects, is an intermediate in the conversion of sitosterol, stigmasterol
and other C28 and C29 phytosterols to cholesterol. On the other hand, the 24-methylene substituent of obtusifoliol was not dealkylated. Each of
the 4-desmethyl C28 and C29 sterols was readily converted to cholesterol, and a significant amount of 7-dehydro-cholesterol was derived from ergosterol
metabolism. The reason for the differences in substrate specificity of these sterols is not clear, but the information may
be useful in the development of new, specific, mechanism-based inhibitors of sterol metabolism. 相似文献
12.
Free and esterified sterols of the common marine dinoflagellateGonyaulax polygramma were identified using capillary gas chromatography—mass spectrometry (GC-MS). Fractions containing free 4α-methyl and 4-desmethyl
sterols were isolated by column chromatography and shown to consist of at least 20 components. Major sterols included 4α,23,24-trimethyl-5α-cholestan-3β-ol
(dinostanol), 4α,23,24-trimethyl-5α-cholest-22E-en-3β-ol (dinosterol), cholest-5-en-3β-ol (cholesterol), 23,24-dimethyl-5α-cholest-22E-en-3β-ol
and 23,24-dimethylcholesta-5,22E-dien-3β-ol. Although the same group of sterols was found in the free and esterified sterol
fractions, the proportions of individual sterols were quite different. The complexity of the sterol distributions, together
with the predominance of dinostanol, distinguishes the sterol composition of this alga from those of other members of theGonyaulacaceae. 相似文献
13.
The low temperature crystallization technique for the enrichment of “minor” components, such as sterols and sterol esters,
from vegetable oils was applied to low erucic acid rapeseed oils. The recovery of free sterols and sterol esters was estimated
by use of14C-cholesterol and14C-cholesterol oleate. 80% of the free sterols and 45% of the sterol esters were recovered in the liquid fraction, while in
two studies total recoveries were 95% and 99%, respectively. This technique showed some selectivity toward the sterol bound
fatty acids when compared to direct preparative thin layer chromatography (TLC) of the crude oil. Gas liquid chromatography
(GLC) analysis of the free and esterified sterols as TMS-derivatives showed very little selectivity in the enrichment procedure.
The fatty acid patterns of the sterol esters demonstrated, however, a preference in the liquid fraction for those sterol esters
which have a high linoleic and linolenic acid content. The content of free sterols was 0.3–0.4% and that of sterol esters
0.7–1.2% of the rapeseed oils in both winter and summer types of low erucic acid rapeseed (Brassica napus) when the lipid classes were isolated by direct preparative TLC of the oils. The free sterols in the seven cultivars or breeding
lines analyzed were composed of 44–55% sitosterol, 27–36% campesterol, 17–21% brassicasterol, and a trace of cholesterol.
The esterified sterols were 47–57% sitosterol, 36–44% campesterol, 6–9% brassicasterol, and traces of cholesterol and Δ5-avenasterol.
The fatty acid patterns of these esters were characterized by ca. 30% oleic acid and ca. 50% linoleic acid, whereas these
acids constitute 60% and 20%, respectively, of the total fatty acids in the oil. Little or no variation in sterol and sterol
ester patterns with locality within Sweden was observed for the one cultivar of summer rapeseed investigated by the low temperature
crystallization technique. 相似文献
14.
Y. C. Mitei J. C. Ngila S. O. Yeboah L. Wessjohann J. Schmidt 《Journal of the American Oil Chemists' Society》2009,86(7):617-625
The phytosterol, tocopherol, and tocotrienol profiles for mkukubuyo, Sterculia africana, manketti, Ricinodendron rautanenni, mokolwane, Hyphaene petersiana, morama, Tylosema esculentum, and moretologa-kgomo, Ximenia caffra, seed oils from Botswana have been determined. Normal-phase HPLC analysis of the unsaponifiable matter showed that among the
selected oils, the most abundant tocopherol and tocotrienol were γ-tocopherol (2232.99 μg/g) and γ-tocotrienol (246.19 μg/g),
detected in manketti and mkukubuyo, respectively. Mokolwane oil, however, contained the largest total tocotrienol (258.47 μg/g).
Total tocol contents found in manketti, mokolwane, mkukubuyo, morama, and moretologa-kgomo oils were 2238.60, 262.40, 246.20,
199.10, and 128.0 μg/g, respectively. GC–MS determination of the relative percentage composition of phytosterols showed 4-desmethylsterols
as the most abundant phytosterols in the oils, by occurring up to 90% in moretologa-kgomo, mkukubuyo, and manketti seed oils,
with β-sitosterol being the most abundant. Mokolwane seed oil contained the largest percentage composition of 4,4-dimethylsterols
(45.93%). Besides 4-desmethylsterols (75%), morama oil also contained significant amounts of 4,4-dimethylsterols and 4-monomethylsterols
(15.72% total). GC–MS determination of the absolute amounts of 4-desmethylsterols, after SPE fractionation of the unsaponifiable
matter, confirmed that β-sitosterol was the most abundant phytosterol in the test seed oils, with manketti seed oil being
the richest source (1326.74 μg/g). The analysis showed total 4-desmethylsterols content as 1617.41, 1291.88, 861.47, 149.15,
and 109.11 μg/g for manketti, mokolwane, mkukubuyo, morama, and moretologa-kgomo seed oils, respectively. 相似文献
15.
The content and composition of sterols and sterol esters in sunflower and poppy seed oils 总被引:1,自引:0,他引:1
Anna Johansson 《Lipids》1979,14(3):285-291
The composition and proportion of free sterols and sterol esters in crude sunflower and poppy seed oils were determined, using
preparative thin layer chromatography followed by gas chromatography with cholesterol as an internal standard. Free sterols
and sterol esters were also isolated in a liquid fraction obtained by low temperature crystallization (−80 C) of the oils
and enriched with minor lipid classes. This enrichment procedure provided a liquid fraction suitable for studies of minor
components in the oils. However, selectivity towards sterol esters was observed since sterols esterified to very long chain
fatty acids (C20–C24) were preferentially retained in the precipitate. The proportions of free and esterified sterols were found to be 0.34 and
0.28%, respectively, in the sunflower oil, whereas the corresponding figures for poppy seed oil were 0.33% and 0.05%. Sunflower
oil was characterized by a relatively high percentage of Δ7-sterols, preferentially obtained in the esterified fraction, and
by very long chain saturated fatty acids of sterol esters. The sterols in poppy seed oil were composed almost entirely of
campesterol, stigmasterol, sitosterol and Δ5-avenasterol, although their percentage distributions were remarkably different
in the free and esterified fraction. 相似文献
16.
Comparative studies of the sterol composition of four sterol fractions, vis., free sterols, sterol esters, sterol glucosides
and esterified sterol glucosides, were conducted on the juice sacs of six varieties of oranges and two tangor varieties. The
sterols quantified in each fraction were β-sitosterol, campesterol, stigmasterol, cholesterol, 24-ethylidene cholesterol,
brassicasterol and 24-methylene cholesterol. Each variety showed its own intrinsic composition for these sterols in the four
sterol fractions.
So. Market. Nutr. Res. Div., ARS, USDA. 相似文献
17.
Capillary gas liquid chromatography analyses were conducted on free and esterified sterol fractions of cotton (Gossypium hirsutum cv. Stoneville 213) floral buds and anthers. The free sterols of both cotton buds and anthers consist mainly of the common
plant sterols sitosterol, stigmasterol and 24ζ-methylcholest-5-en-3β-ol. The composition of esterified sterols of cotton buds
and anthers were similar, and consisted of pollinastanol, 31-norcycloartanol, cycloartenol, 31-norcycloartenol, 24-dehydropolinastanol
and sitosterol. Desmosterol was also present in both the free and esterified sterols of anthers. The identities of the sterols
were confirmed by gas chromatography-mass spectrometry analyses. Esterified sterols accounted for 46.7 and 88.7% of total
sterols of cotton bud and anthers, respectively. The ratio of esterified sterol to free sterol per gram of tissue is about
8∶1 in anthers. The Δ5-sterols of the esterified sterols of cotton buds and anthers account for only 17 and 9.2% of the total sterols, respectively. 相似文献
18.
Analysis of free and esterified sterols in vegetable oils 总被引:2,自引:6,他引:2
T. Verleyen M. Forcades R. Verhe K. Dewettinck A. Huyghebaert W. De Greyt 《Journal of the American Oil Chemists' Society》2002,79(2):117-122
In vegetable oils, phytosterols occur as free sterols or as steryl esters. Few analytical methods report the quantification
of esterified and free sterols in vegetable oils. In this study, esterified and free sterols were separated by silica gel
column chromatography upon elution with n-hexane/ethyl acetate (90∶10 vol/vol) followed by n-hexane/diethyl ether/ethanol (25∶25∶50 by vol). Both fractions were saponified separately and the phytosterol content was
quantified by GC. The analytical method for the analysis of esterified and free sterols had a relative standard deviation
of 1.16% and an accuracy of 93.6–94.1%, which was comparable to the reference method for the total sterol analysis. A large
variation in the content and distribution of the sterol fraction between different vegetable oils can be observed. Corn and
rapeseed oils were very rich in phytosterols, which mainly occurred as steryl esters (56–60%), whereas the majority of the
other vegetable oils (soybean, sunflower, palm oil, etc.) contained a much lower esterified sterol content (25–40%). No difference
in the relative proportion of the individual sterols among crude and refined vegetable oils was observed. 相似文献
19.
Taro Matsumoto Toshihiro Akihisa Shin-ichi Soma Michio Takido Shushichi Takahashi Sakae Yamanouchi 《Journal of the American Oil Chemists' Society》1986,63(4):544-546
The composition of the unsaponifiable lipid, which consisted of squalene, squalene-2,3-oxide, triterpene alcohols, 4α-methyl-sterols,
and sterols, of the seed oils ofPanax ginseng andP. quiquefolium, was determined. Squalene was the most abundant component (54%) of the unsaponifiable lipid fromP. ginseng, whereas sterols constituted the principal components of unsaponifiable lipid fromP. quiquefolium. Both ginseng seed oils showed specific features in sterol composition, i.e., 28-isofucosterol (40%) and 24-ethyl-22E-dehydrocholesterol
(66%) constituted the most predominant components of the sterol fractions fromP. ginseng andP. quiquefolium seed oils, respectively. 相似文献
20.
The content of 4-demethyl-, 4-monomethyl- and 4,4-dimethylsterols in 13 vegetable oils was found to vary between 0.10–1.4%,
0.01–0.08% and 0.02–0.29%, respectively. The largest amount of demethylsterols was found in maize and wheat germ oils, whereas
the largest amounts of the dimethylsterols were found in olive and linseed oils. The predominating demethylsterols were sitosterol,
campesterol, stigmasterol and Δ5-avenasterol. Among the 4-monomethylsterols, obtusifoliol, gramisterol, cycloeucalenol and citrostadienol predominated, but
usually more than 10 components were found in this fraction. The composition of the 4,4-dimethylsterol fraction was also rather
complex, with the 9,19-cyclopropanesterols together with α- and β-amyrin predominating. In most of the oils, characteristically
high or low percentages of some sterols were found, and a few specific sterols were also noted. A scheme useful for characterization
is presented. 相似文献