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1.
The unsaponifiables separated from 20 vegetable oils were divided into sterol and three other (less polar compound, triterpene
alcohol, and 4-methylsterol) fractions by preparative thin layer chromatography. The amounts of the sterol fractions were
more than ca. 30% in the unsaponifiables from all of the oils, except tohaku, pumpkin seed, and fagara seed oils. Composition
of the sterol fractions were determined by gas liquid chromatography. Individual components of the sterol fractions were identified
by gas liquid chromatography and combined gas liquid chromatography-mass spectrometry. β-Sitosterol was found as the most
predominant component in the sterol fractions from all oils, except two, i.e. the sterol fraction from pumpkin seed oil contained
no detectable amount of β-sitosterol and the sterol fraction from akamegashiwa oil contained Δ5-avenasterol as the most abundant component. Campesterol, stigmasterol, Δ5-avenasterol, Δ7-stigmastenol, and Δ7-avenasterol and also trace amounts (at the very least) of cholesterol and brassicasterol were found in most of the oils analyzed.
It may be noted that a large amount (ca. 9%) of cholesterol was detected in the sterol fraction from capsicum seed oil. The
presence of 24-methylenecholesterol and Δ5-avenasterol in the sterol fraction of akamegashiwa oil was demonstrated by isolation of these sterols. 相似文献
2.
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
3.
T. Itoh K. Yoshida T. Yatsu T. Tamura T. Matsumoto G. F. Spencer 《Journal of the American Oil Chemists' Society》1981,58(4):545-550
Nine Spanish olive oils, including three each of virgin (pressed oil), refined virgin, and B-residue (solvent-extracted pomace
oil) oils from different commercial sources, have been analyzed for their unsaponifiable matter (USM). Four sterolic fractions
separated from the oils have been analyzed by preparative thin-layer chromatography (TLC); these fractions are triterpene
alcohols, 4-methylsterols, sterols and triterpene dialcohols. The compositions of the four sterolic fractions were determined
as their acetates by gas-liquid chromatography (GLC) on an OV-17 glass capillary column. Identification of each component
was carried out by argentation TLC, GLC and combined gas chromatography-mass spectrometry (GC-MS); 44 components were identified,
of which four: 24-methylene-31-nor-9(11)-lanostenol, 24-methyl-31-nor-E-23-dehydrocycloartanol, 24-ethyl-E-23-dehydrolophenol
and 5,E-23-stigmastadienol, were considered to be new sterols from natural sources. Several characteristics, including the
content of triteterpene dialcohols in the USM and that of C-24(28) unsaturated sterols in each of the four sterolic fractions,
which can be used to distinguish between virgin and B-residue olive oils, were observed. 相似文献
4.
Acid-catalyzed isomerization of fucosterol and Δ5-avenasterol 总被引:1,自引:0,他引:1
Afaf Kamal-Eldin Kaisu Määttä Jari Toivo Anna-Maija Lampi Vieno Piironen 《Lipids》1998,33(11):1073-1077
This work shows that fucosterol, Δ5-avenasterol, and similar ethylidene-side chain sterols can undergo acid-catalyzed isomerization to give a mixture of five
isomers. Four isomers formed from fucosterol were analyzed, using gas chromatography-mass spectrometry, and were characterized
as Δ5-avenasterol two Δ5,23-stigmastadienols, and Δ5,24(250)-stigmastadienol. When the unsaponifiables fraction from oat oil was subjected to acid hydrolysis, the two Δ5,23-stigmastadienol isomers and Δ5,24(25)-stigmastadienol were detected while fucosterol coeluted with sitosterol. Interisomerization of ethylidene-side chain sterols
represents a limitation to the use of the acid hydrolysis method in the determination of sterols in food and other plant materials
rich in these sterols, e.g., oat lipids. 相似文献
5.
Sterol composition of 19 vegetable oils 总被引:6,自引:4,他引:6
The unsaponifiables from 19 vegetable oils were divided into a sterol and three other fractions by thin-layer chromatography.
All except olive and palm kernel oils gave the sterol fraction in a large quantity. Compositions of the sterol fractions were
determined by gas liquid chromatography. Identification of each sterol was carried out by gas liquid chromatography and combined
gas chromatograph-mass spectrometry. Campesterol, stigmasterol and β-sitosterol were present in all oils, and a minor amount
of cholesterol in majority of the oils. Brassicasterol occurrence was widespread but its content was extremely small in oils
other than rapeseed oil. Other sterols, presumably δ7-stigmastenol and δ5- and δ7-avenasterol were detected in most of the oils. 相似文献
6.
Claudia Guillaume Leandro Ravetti Debashree Lala Ray Joshua Johnson 《Journal of the American Oil Chemists' Society》2012,89(1):29-39
Sterols are important lipids related to the quality of olive oil and broadly used for checking its genuineness. Recent analyses
have identified that some Australian olive oils would not meet international standards for total content of sterols or for
certain individual components. Several research works indicate that there are some significant correlations between cultural
and processing practices and sterols content and composition. In this work the horticultural and processing practices that
may have an impact on the sterol content and profile of the most important Australian varieties were analysed. The information
generated with this study aims to solve a legislation problem as well as maximising the nutritional and health benefits of
Australian olive oils. The evaluation was undertaken using three different varieties and the processing practices evaluated
were: irrigation, fruit size, maturity, malaxing time, malaxing temperature and delays between harvest and process. The total
content of sterols and their composition in olive oil is strongly influenced by genetic factors and year. Processing practices
particularly affect triterpene dialcohols and stigmasterol while horticultural practices and fruit characteristics tend to
affect more significantly other sterols such as β-sitosterol, sitostanol, Δ5-avenasterol and Δ7-avenasterol. 相似文献
7.
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
8.
The triterpene alcohol fraction in several virgin olive oils and the corresponding oils refined by alkali and by physical
processes was analyzed by gas chromatography. A Δ7 compound was detected in all refined olive oils but not in virgin olive oils. This compound was tentatively identified by
gas chromatography-mass spectrometry as 24-methyl-5α-lanosta-7,24-dien-3β-ol, a 24-methylenecycloartanol isomer produced during
the refining process by the opening of the 9, 19 cyclopropane ring with formation of a double bond in the Δ7 position and the translocation of a double bond in the side chain from the 24–28 to the 24–25 position. 相似文献
9.
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
10.
Camelina oil and its unusual cholesterol content 总被引:1,自引:1,他引:1
V. K. S. Shukla P. C. Dutta W. E. Artz 《Journal of the American Oil Chemists' Society》2002,79(10):965-969
The oil in Camelina sativa L. Crantz has a combined linolenic and linoleic acid content that is greater than 50% and a relatively low saturated FA content
(∼10%). Although the FA composition has been reported, no information is available on the sterol composition of camelina oil.
The derivatized plant sterols were separated and quantified with capillary GC and their identity confirmed with GC-MS. The
refined camelina oil sample contained approximately 0.54 wt% unsaponifiables, and over 80% of the unsaponifiables were desmethylsterols.
Perhaps the most unusual characteristic of camelina oil is its relatively high content of cholesterol, particularly for a
vegetable oil, since it contains several times the cholesterol found in other “high-cholesterol” vegetable oils. Camelina
oil also contains relatively large amounts of another unusual sterol, brassicasterol. The major sterols identified in the
camelina oil included cholesterol (188 ppm), brassicasterol (133 ppm), campesterol (893 ppm), stigmasterol (103 ppm), sitosterol
(1,884 ppm), and Δ5-avenasterol (393 ppm). 相似文献
11.
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
12.
F. Dionisi J. Prodolliet E. Tagliaferri 《Journal of the American Oil Chemists' Society》1995,72(12):1505-1511
A method involving reversed-phase high-performance liquid chromatography with amperometric detection has been developed for
the analysis of tocopherols and tocotrienols in vegetable oils. The sample preparation avoids saponification. Recoveries of
α-tocotrienol and γ-tocotrienol in extra virgin olive oil were 97.0 and 102.0%, respectively. No tocotrienols were detected
in olive, hazelnut, sunflower, and soybean oils, whether virgin or refined. However, relatively high levels of tocotrienols
were found in palm and grapeseed oils. This method could detect small quantities (1–2%) of palm and grapeseed oils in olive
oil or in any tocotrienol-free vegetable oil and might, therefore, help assess authenticity of vegetable oils. 相似文献
13.
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
14.
R. E. Worthington H. L. Hitchcock 《Journal of the American Oil Chemists' Society》1984,61(6):1085-1088
A method for separating and quantitating seed oil steryl esters and free sterols was developed using a combination of preparative
column, thin layer (TLC), and gas liquid chromatography (GLC). Cholesteryl heneicosanoate and cholesterol served as internal
standards. The method was applied to corn-oil samples (Mazola, Kroger) obtained from the local market and peanut-oil samples
prepared in the laboratory from commercial varieties of peanuts (Florunner, Starr). Concentration (mg/100 g oil; mean ± SD)
of steryl esters and free sterols in the 4 oils were: Mazola, 1420±40 and 370±8; Kroger, 950±40 and 320±4; Florunner, 74±0.5
and 150±3; and Starr, 51±0.5 and 130±2. Sitosterol was the major sterol in both the free sterol and steryl ester fractions
of all oils and together with campesterol, stigmasterol and Δ5-avenasterol made up 90–95% of all sterols. Steryl esters of peanut oil contained higher proportions of linoleic acid and
long-chain acids (C20–C24) than did whole oil. Corn-oil steryl esters also contained a higher proportion of linoleic acid than did whole oil. Squalene
was the major hydrocarbon of all oils with the remaining hydrocarbon fraction consisting of a mixture of compounds.
Presented at the AOCS meeting, Toronto, May 1982. 相似文献
15.
Use of high-resolution 13C nuclear magnetic resonance spectroscopy for the screening of virgin olive oils 总被引:2,自引:0,他引:2
Rosario Zamora Virginia Alba Francisco J. Hidalgo 《Journal of the American Oil Chemists' Society》2001,78(1):89-94
13C Nuclear magnetic resonance (NMR) spectra of 104 oil samples were obtained and analyzed in order to study the use of this
technique for routine screening of virgin olive oils. The oils studied included the following: virgin olive oils from different
cultivars and regions of Europe and north Africa, and refined olive, “lampante” olive, refined olive pomace, high-oleic sunflower,
hazelnut, sunflower, corn, soybean, rapeseed, grapeseed, and peanut oils, as well as mixtures of virgin olive oils from different
geographical origins and mixtures of 5–50% hazelnut oil in virgin olive oil. The analysis of the spectra allowed us to distinguish
among virgin olive oils, oils with a high content of oleic acid, and oils with a high content of linoleic acid, by using stepwise
discriminant analysis. This parametric method gave 97.1% correct validated classifications for the oils. In addition, it classified
correctly all the hazelnut oil samples and the mixtures of hazelnut oil in virgin olive oil assayed. All of these results
suggested that 13C NMR may be used satisfactorily for discriminating some specific groups of oils, but to obtain 100% correct classifications
for the different oils and mixtures, more information than that obtained from the direct spectra of the oils is needed. 相似文献
16.
Rosario Zamora Gemma Gómez M. Carmen Dobarganes Francisco J. Hidalgo 《Journal of the American Oil Chemists' Society》2002,79(3):261-266
One hundred nine oil samples were separated chromatographically to obtain oil fractions with a decreased TAG content but with
enhanced levels of the minor components that define oil genuineness and quality. The oils, which included virgin olive oils
from different cultivars and regions of Europe and north Africa and refined olive, “lampante” olive, refined olive pomace,
hazelnut, rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils, were fractionated on a silica gel
column with hexane/diethyl ether as the mobile phase eluent. The method was highly reproducible, and the fraction obtained
contained about 15% unmodified TAG and 85% polar compounds, which included polymeric TAG, oxidized TAG, DAG, MAG, and FFA,
in addition to other minor polar components of the oils. The presence of these compounds, in an enriched fraction, should
provide information about the thermal, oxidative, and hydrolytic alterations of the oils, as well as many compounds of interest
in determining oil genuineness. The results indicate that these fractions can provide more information than the original oils
for NMR or other spectroscopic studies used in the determination of oil quality. 相似文献
17.
Effect of extraction system, stage of ripeness, and kneading temperature on the sterol composition of virgin olive oils 总被引:3,自引:2,他引:1
A. Koutsaftakis F. Kotsifaki E. Stefanoudaki 《Journal of the American Oil Chemists' Society》1999,76(12):1477-1481
Comparative extraction trials were carried out among a classical pressing, a dual-, and a three-phase centrifugation system
using olive crops of Koroneiki variety. Two different kneading temperatures, 30 and 45°C, were tested at three stages of ripeness
for two consecutive years of harvest, 1995–1996 and 1996–1997. Composition of the sterol fraction was determined in the resulting
olive oil samples (n=72). Stigmasterol was found to be affected by the extraction system; it was obtained in the highest amount in the pressing
system. The ratio campesterol/stigmasterol was significantly higher in oils extracted by dual- and three-phase centrifugation.
Sterols were significantly affected by the ripening stage of the fruit. During December, the ratio campesterol/stigmasterol
reached the maximal and β-sitosterol the minimal values; this appears to be the optimal period for harvesting the olives.
Comparison of the different kneading temperatures showed that at 30°C, Δ5-avenasterol and campesterol/stigmasterol ratio reached higher values than at 45°C. 相似文献
18.
Francisco J. Hidalgo Manuel Alaiz Rosario Zamora 《Journal of the American Oil Chemists' Society》2002,79(7):685-689
Twenty-eight virgin olive oils—from different regions of Spain and prepared from olive drupes of different varieties—and six
refined olive oils were analyzed to determine the presence of proteins in these oils. All oils studied showed the presence
of proteins in the range of 7–51 μ/100 g of oil. There were no significant differences in protein content in oils from different
varieties or between virgin or refined oils. In addition, all oils exhibited analogous amino acid patterns, suggesting a similarity
among protein fractions obtained from different oils. A polypeptide with an apparent M.W. of 4600 Da was common to the isolated
protein fractions. These results suggest that this polypeptide is a previously unknown minor component in olive oils. No clear
influence of this component on oil stability was observed when oil stabilities were estimated as a function of phenol, tocopherol,
phosphorus, and protein contents of the oils. 相似文献
19.
A laboratory study of the bleaching process in stigmasta-3,5-diene concentration in olive oils 总被引:1,自引:0,他引:1
J. Serra Bonveh M. Solvia Torrent F. Ventura Coll 《Journal of the American Oil Chemists' Society》2001,78(3):305-310
The bleaching effect was simulated in pilot plant by measuring the influence of temperature (40, 50, 60, 70, 80, and 90°C),
time (5, 10, 15, 20, 25, and 30 min), and concentration of solid adsorbent [1.5 and 8% (w/w) of Tonsil supreme NFF] on stigmasta-3,5-diene
(STIG) obtained by dehydration of steroidal compounds. Conditions were chosen to simulate those used in industrial operations.
The presence of refined oils in extra virgin olive oil can be detected by these newly formed steroid hydrocarbons. Experimental
results indicated that STIG did not exceed an imposed limit of 0.15 mg/kg in extra virgin olive oil, when oils were bleached
with 1.5% earth at temperatures ≤80°C for 30 min in admixed to oils sold as virgin. A large proportion of the adulterations
were not detectable by the official methods. Color determinations (CIE-1931) chromatic coordinates) were replicated on a refined
oil and in admixed extra virgin olive oil. Color of olive oil was not significantly affected by mixing with refined oil (≤20%). 相似文献
20.
The composition of the free sterols and the sterol esters of freshly harvested seeds of rape, sunflower and poppy was compared
to that of stored seeds. The sterol composition of rapeseed was not changed during storage, whereas in sunflower seed the
free sterols had less of Δ5-avenasterol and Δ7-stigmastenol in ten-month-old seeds compared to fresh seeds. The greatest relative
changes were observed for esterified sterols in poppy seed, with a drop in the percentage of Δ5-avenasterol from 25.3% in
freshly harvested to 16.9% in seeds stored for 10 months. 相似文献