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1.
Analysis of soybean lecithins and beef phospholipids by HPLC with an evaporative light scattering detector 总被引:5,自引:0,他引:5
S. L. Melton 《Journal of the American Oil Chemists' Society》1992,69(8):784-788
Linear (r > 0.99) calibration curves were obtained for 10–150 μg of phosphatidylethanolamine (PE), 10–75 μg of phosphaditylinositol
(PI), phosphaditylserine (PS) and lysophosphatidylethanolamine, 10–100 μg of phosphatidic acid (PA) and 10–250 μg of phosphatidylcholine
(PC) by high-performance liquid chromatography analyses with an evaporative light scattering detector, a Zorbax 7-μm silica
column and gradient elution with two solvents. One solvent (A) contained 415 mL isooctane (IOCT), 5 mL tetrahydrofuran (THF),
446 mL isopropanol (IPA), 104 mL CHCl3 and 30 mL H2O; and the other solvent (B) contained 216 mL IOCT, 4 mL THF, 546 mL IPA, 154 mL CHCl3 and 80 mL H2O. The gradient in which 100% A linearly changed to 100% B in 20 min followed by 12 min of 100% B and then a linear change
to 100% A during 5 min separated PE, PS and PC in soybean lecithins and beef lipids, but failed to resolve PI and PA. In these
same samples, less polar lipids were separated from phospholipids (PL) by elution from Bond-Elut silica columns with diethyl
ether/hexane (20:80, vol/vol), and PL were recovered by elution with methanol. This procedure is useful for concentration
of minor lipid components. Levels of PE, PI-PA, PS and PC were higher in granular than in liquid lecithin, and PC was the
most abundant PL in soybean lecithins and beef lipids. 相似文献
2.
An improved method for the analysis of phospholipids by normal-phase HPLC is described. Addition of methanol and acetonitrile
to a gradient based on 2-propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids
(PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration
curves were linear within the range of 5–40 μg with detection limits below 1 μg for PE and PC, and CV ranged from 0.6 to 9.6%.
PL present in surfactant homogenates were separated by a solid-phase extraction (SPE) procedure before HPLC analysis. This
methodology gave a recovery of 95% and combined SPE-HPLC and quantification of biological PL within a 30-min run. The use
of ELSD detection of the eluted compounds was precise, linear, and sensitive. 相似文献
3.
The effect of N-ethyl-maleimide (NEM) on Δ5-and Δ6-desaturase activities and the incorporation of substrates and products into different
microsomal lipid classes and phospholipid (PL) subclasses were studied in human fetal liver microsomes, obtained after legally
approved therapeutic abortion. Desaturase activities were measured by a radiochemical method using reversed-phase high-performance
liquid chromatography (HPLC). After nonphospholipid (NPL) and PL separation on silica cartridges, the radioactivity in different
lipids of the NPL group was assessed by two-dimensional thin-layer chromatography, and their fatty acid (FA) composition by
gas-liquid chromatography. The PL subclasses were separated, and the distribution of radioactivity between products and substrates
was determined in PL subclasses. NEM inhibited the Δ5- and Δ6-desaturase activities in the n−6 series of FA but not the Δ6-desaturase
activity in the n−3 series, which suggests the existence of two distinct Δ6-desaturases, one for the n−6 series and another
for the n−3 series. Whether NEM was present or absent, most of the radioactivity was recovered in the free FA form (about
80%). The desaturation products, obtained in the presence or absence of NEM, were preferentially incorporated into PL, suggesting
a channeling of the newly synthesized FA toward microsomal PL. The comparison of the distribution of substrates and products
incorporated into the different PL classes showed that most of the labeled FA were incorporated into phosphatidylcholine and
to a lesser degree into phosphatidylethanolamine. 相似文献
4.
Constituent lipids of surface membranes (SM) isolated fromLeishmania donovani promastigotes were analyzed and compared with those obtained from whole cells and an isolated kinetoplast-mitochondrion fraction
(KM). On a dry weight basis, the total extractable lipids constituted ≈47%, 12% and 24% of the SM, cells and KM, respectively.
The total lipids of SM, cells and KM all were composed of ≈70% phospholipids (PL), 20–25% neutral lipids and 5–10% glycolipids.
Sterols and diglycerides composed 60% and 30%, respectively, of the various neutral lipid fractions. Several mannose- and
galactose-containing glycolipids were fractionated but not identified. The glycolipid fractions from cells and SM had demonstrable
antigenic activities with rabbit anti-SM sera. Striking quantitative differences were apparent between the PL profiles of
the 3 cellular components examined. The PL of SM, whole cells and KM, respectively, were composed of: 15%, 51% and 24% phosphatidylcholine;
37%, 13% and 11% phosphatidylethanolamine (PE); 18%, 10% and 14% phosphatidylinositol; 10%, 1% and 4% phosphatidylserine and
traces of cardiolipin, phosphatidylglycerol and phosphatidic acid. An unknown PL containing sphingosine, choline and vicinal
hydroxyl groups but no free amino moieties made up ≈19% of the PL of SM and whole cells, but it constituted ≈27% of the PL
of KM. The PL side chain constituents of whole cells and SM were composed mainly of longchain fatty acids (C18–20). Further,
over 50% of the PE of SM was in the alkyl and alK-1-enyl ether forms. These SM properties might contribute to the organism's
resistance to digestion in the hydrolytic environs of both its insect vector and mammalian hosts. 相似文献
5.
The carbon and energy source for aerobically grown cultures ofCandida guilliermondii profoundly influenced the neutral lipid content and the fatty acid composition of the individual lipid components. Methanol
(0.80%, w/v) grown cells cultivated at 30 C in presence of 0.025% ammonium sulfate contained 12% total lipids, 67% of which
was neutral lipids. Glucose (0.74%, w/v) or ethanol (0.53%, w/v) grown cells contained 21–22% total lipids, 80% of which was
neutral lipids, under the same conditions. Methanol-grown cells contained a decreased 18∶1 acid (52–54% of total fatty acids)
and an increased 18∶2 acid (23–25%), as compared with glucose- or ethanol-grown cells which contained 57–66% 18∶1 acid and
8–14% 18∶2 acid, in both neutral and polar lipid fractions. The relationship between methanol metabolism and desaturation
of fatty acid in yeast was discussed. 相似文献
6.
Afaf Kamal-Eldin Lars Åke Appelqvist 《Journal of the American Oil Chemists' Society》1994,71(2):135-139
Seeds from different collections of cultivatedSesamum indicum Linn. and three related wild species [specifically,S. alatum Thonn.,S. radiatum Schum and Thonn. andS. angustifolium (Oliv.) Engl.] were studied for their oil content and fatty acid composition of the total lipids. The wild seeds contained
less oil (ca. 30%) than the cultivated seeds (ca. 50%). Lipids from all four species were comparable in their total fatty acid composition, with palmitic (8.2–12.7%), stearic
(5.6–9.1%), oleic (33.4–46.9%) and linoleic acid (33.2–48.4%) as the major acids. The total lipids from selected samples were
fractionated by thin-layer chromatography into five fractions: triacylglycerols (TAG; 80.3–88.9%), diacylglycerols (DAG; 6.5–10.4%),
free fatty acids (FFA; 1.2–5.1%), polar lipids (PL; 2.3–3.5%) and steryl esters (SE; 0.3–0.6%). Compared to the TAG, the four
other fractions (viz, DAG, FFA, PL and SE) were generally characterized by higher percentages of saturated acids, notably palmitic and stearic
acids, and lower percentages of linoleic and oleic acids in all species. Slightly higher percentages of long-chain fatty acids
(20∶0, 20∶1, 22∶0 and 24∶0) were observed for lipid classes other than TAG in all four species. Based on the fatty acid composition
of the total lipids and of the different acyl lipid classes, it seems thatS. radiatum andS. angustifolium are more related to each other than they are to the other two species. 相似文献
7.
The fatty acid (FA) composition and distribution in a variety of phospholipids (PL) and neutral lipids (NL) at two discrete
stages during the embryonic rat brain development were investigated. Over 96% of the FA were acylated into fetal brain PL
at embryonic day 17 after the peak of neuronal proliferation and at embryonic day 20, one day prior to delivery. Phosphatidylcholine
constituted approximately 60% of the total PL pool, phosphatidylethanolamine (PE) 30%, phosphatidylserine (PS) 6%, and phosphatidylinositol
(PI) 4%. The diacylglycerols and triacylglycerols constituted 1–2% of the fetal brain lipids. α-Linolenic acid (18∶3n−3) and
linoleic acid (18∶2n−6) were found in very low amounts in all fetal brain PL and NL. The percentage of the n−6 polyunsaturated
FA, consisting of arachidonic acid (AA), 22∶4n−6 and 22∶5n−6, remained unchanged in all the fractions, except in Pl, in which
the proportion of AA increased. The concentration of docosahexaenoic acid (DHA) increased with age in all the fractions, with
the bulk of accumulation accounted for by its increase in PE and, to a lesser extent, in PS. This finding suggests a “DHA
accretion spurt” during the last three days of pregnancy. 相似文献
8.
Lipid and fatty acid composition and energy partitioning during embryo development in the shrimp Macrobrachium borellii 总被引:2,自引:0,他引:2
Energy partitioning, composition of lipids and fatty acids, and their utilization by embryos were determined in the lecithotrophic
shrimp Macrobrachium borellii during seven development stages. The biochemical composition at stage I is represented by lipids, proteins, and carbohydrates,
with 29.3, 28.7, and 0.2% dry weight, respectively. The former two were identified as the major energy-providing components,
contributing 131 and 60 cal/100 mg egg, dry weight, respectively. The overall conversion efficiency (CE) was 45.0% (calculated
as percentage of vitelline energy transformed into embryonic tissues). Lipids were the most important energy reserve (CE 39.3%),
followed by proteins (CE 57.1%), both being simultaneously utilized during development while carbohydrates were synthesized
de novo (CE 587.5%). Variation in the lipid class composition of embryos and vitellus showed an accumulation of triacylglycerols
(TAG) and phospholipids (PL) up to stage IV, a more active accumulation and selective utilization phase (stages V and VI),
and a consumption and de novo synthesis period until hatching. Structural lipids (PL and cholesterol) and pigment astaxanthin were selectively conserved
in embryos, but TAG, hydrocarbons, and esterified sterols were preferentially depleted. Monounsaturated fatty acids (FA) were
the major group in TAG, whereas polyunsaturated FA (PUFA) were the major group in PL after organogenesis. Certain PUFA such
as 22∶6n−3 and 20∶5n−3 were selectively accumulated in PL. 相似文献
9.
Hiromi Yoshida Yuka Tomiyama Masayuki Saiki Yoshiyuki Mizushina 《Journal of the American Oil Chemists' Society》2007,84(11):1031-1038
The positional distribution of fatty acids (FA) of triacylglycerols (TAG) and major phospholipids (PL) prepared from four
cultivars of peas (Pisum sativum L.) were investigated as well as their tocopherol contents. The lipids extracted from these peas were separated by thin-layer
chromatography (TLC) into seven fractions. The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while the
other components were also present in minor proportions (5.6–9.2%). γ-Tocopherol was present in the highest concentration,
and α- and δ-tocopherols were very small amounts. The main PL components isolated from the four cultivars were phosphatidylcholine
(42.3–49.2%), followed by phosphatidylinositol (23.3–25.2%) and then phosphatidylethanolamine (17.7–20.5%). Small but significant
differences (P < 0.05) in FA distribution existed when different pea cultivars were determined. However, the principal characteristics of
the FA distribution in the TAG and the three PL were evident among the four cultivars; unsaturated FA were predominantly located
in the sn-2 position, and saturated FA primary occupied the sn-1 or sn-3 position in the oils of the peas. These results suggest that the regional distribution of tocopherols and fatty acids in
peas is not dependent on the climatic conditions and the soil characteristics of the cultivation areas during the growing
season. 相似文献
10.
The quantitative distribution of 23 acyl lipid classes and unsaponifiable matter in kernels of amylomaize, LG-11 hybrid maize
and waxy maize is described. LG-11 and waxy maize were normal (oil content) varieties, containing 4.9% and 5.1% lipid, respectively,
while amylomaize (9.3% lipid) was a high oil variety. The distribution of kernel lipids was 76–83% in germ, 1–2% in pericarp,
1% in tip cap, 1–11% in starch, and 13–15% in aleurone plus the nonstarch fraction of the starchy endosperm. Germ contained
39–47% lipid, which was nostly triglyceride (TG), with some steryl esters (SE) and diglycerides (DG), and small amounts of
glycolipids (GL) and phospholipids (PL). Aleurone lipids appeared to be TG with some free fatty acids (FFA) and SE. The other
nonstarch lipids in starchy endosperm were FFA with very small amounts of SE, DG, GL and PL. The starches had a little surface
lipid (FFA) and true (internal) starch lipid (FFA, lyso-PL) in quantities roughly related to amylose content (amylomaize =ca.
73% amylose, 1.0% lipid; LG-11=23% amylose, 0.7% lipid; waxy maize =<5% amylose, 0.2% lipid). Pericarp lipids (0.8–2.5%) were
mainly unsaponifiable matter, the acyl lipids being TG, SE, DG and FFA. Tip cap lipids (2.5–2.9%) had more TG, GL and PL than
pericarp lipids, but were otherwise similar. Pericarp lipids and endosperm nonstarch lipids appeared to have suffered extensive
degradation at some time during kernel development or after harvesting, while lipids in starch, germ and tip cap were evidently
unaffected. FFA and lyso-PL are regarded as normal components of maize starch (rather than degradation products) and may occur
as amylose inclusion complexes. 相似文献
11.
Roy R. Chao Steven J. Mulvaney Hsimin Huang 《Journal of the American Oil Chemists' Society》1993,70(2):139-143
Edible beef tallow was extracted by supercritical CO2 in a dynamic mode at pressures from 138 to 345 bars and temperatures of 40 and 50°C. The lipid fractions were collected at
34.5 bar/40°C. A retrograde behavior of lipid solubility was observed around 170–175 bar. The ranges of the cholesterol concentration
[chol.], were 300–450 mg/100 g and 50–200 mg/100 g lipid for the fractions extracted at 138 bar and 345 bar, respectively.
Beef tallow was also extracted with sequentially varied pressures of 138, 345 and 138 bars at 40°C and collected at 34.5 bar/40°C.
The results showed that after 20 kg CO2 was used for extracting 100 g of loaded beef tallow the weight of the residual beef tallow remaining in the extractor was
23 g with [chol.] of 49 mg/100 g lipid. The lower [chol.] of the residual beef tallow represents a 60–70% reduction in cholesterol
content, when compared with untreated beef tallow where [chol.] ranges from 130 to 160 mg/100 g lipid. To isolate lipid fractions
containing higher [chol.], beef tallow was extracted at 345 bar/40°C and then fractionated into three separators connected
in series with decreasing pressures of 173 bar, 117 bar, and 34.5 bar at 40°C, respectively. The results showed that the fractions
collected from the third separator (34.5 bar) contained concentrated [chol.] ranging from 272 to 433 mg/100 g lipid. The fatty
acid analysis revealed that the fractions containing high [chol.] generally consisted of high concentrations of myristic and
palmitoleic acids but low concentrations of stearic and oleic acids. 相似文献
12.
Masaki Kaneniwa Song Miao Chunhong Yuan Haruka Lida Yutaka Fukuda 《Journal of the American Oil Chemists' Society》2000,77(8):825-831
The lipid and fatty acid composition of muscle of 10 species of freshwater fish obtained from a market of Shanghai City was
examined. Total lipids (TL) ranged over 0.9–4.7% of muscle for all samples. The content of triacylglycerol (TG) in muscle
ranged over 0.2–3.4% and that of polar lipids (PL) was 0.5–1.3%. Differences of TL content were dependent on TG contents.
The predominant important fatty acids (>10% of the total fatty acids in TL) were 16∶0 and 18∶1n−9 with some 16∶1n−7, 18∶2n−6,
and 22∶6n−3. The polyunsaturated fatty acids (PUFA) content was 10.2–43.4%, and especially Chinese sea bass contained above
20% of 22∶6n−3 in the total fatty acids. There were higher levels of PUFA such as 20∶5n−3 and 22∶6n−3 in PL than in neutral
lipids. Muscle of the silver carp was stored at 20°C, and changes of lipid classes during storage were examined. Free fatty
acids increased, and PL decreased during storage. This phenomenon was inhibited by heating the muscle, suggesting that lipid
hydrolysis by phospholipase occurred in silver carp muscle. 相似文献
13.
Isolation of Pure Phospholipid Fraction from Egg Yolk 总被引:1,自引:0,他引:1
Witold Gładkowski Anna Chojnacka Grzegorz Kiełbowicz Tadeusz Trziszka Czesław Wawrzeńczyk 《Journal of the American Oil Chemists' Society》2012,89(1):179-182
The phospholipid (PL) fraction from egg yolk was isolated and purified. In the procedure applied (method 2) the egg yolk was
extracted with ethanol, precipitated using acetone chilled to −20 °C and washed using acetone. The purity of the samples was
checked by HPLC analysis using a Charged Aerosol Detector (CAD). The results were compared with those obtained for the phospholipid
fraction isolated and purified by deoiling yolk before extraction and the precipitation of PL with acetone chilled to 4 °C
(method 1). The use of acetone chilled to −20 °C to precipitate and wash the phospholipids yielded the phospholipid fraction
with 100% purity (78.7 ± 0.2 of phosphatidylcholine and 21.3 ± 0.2 of phosphatidylethanolamine). When deoiling and the 4 °C
purification process was used (method 1) 0.4 ± 0.1% cholesterol and some traces of triacylglycerols remained in the PL fraction. 相似文献
14.
Hiromi Yoshida Yuka Tomiyama Naoko Yoshida Masayuki Saiki Yoshiyuki Mizushina 《Journal of the American Oil Chemists' Society》2008,85(6):535-541
Seed oils from four legume cultivars of Vicia faba, grown in Japan, were extracted and classified by thin-layer chromatography (TLC) into eight fractions. The major lipid components
were triacylglycerols (TAG: 48.8–50.1%) and phospholipids (PL: 47.5–50.5%), while hydrocarbons (HC), steryl esters (SE), free
fatty acids (FFA), diacylglycerols (1,3- and 1,2-DAG) and monoacylglycerols (MAG) were present in minor proportions (1.8–2.4%).
All lipid samples had high amounts of total unsaturated FA, representing 79.7–82.8% and 77.6–79.7% for TAG and PL, respectively.
Molecular species and FA distributions of TAG, isolated from the total lipids in the broad beans, were analyzed by a combination
of argentation-TLC and GC. Fourteen different molecular species were detected. With a few exceptions, the main TAG components
were S2D (6.1–8.9%), SD2 (7.8–10.5%), SMT (6.3–8.5%), M2D (4.5–6.2%), MD2 (18.9–21.8%), D3 (21.0–23.9%) and MDT (8.1–10.2%) (where S, M, D, and T denote a saturated fatty acid, a monoene, a diene, and a triene, respectively).
These results suggest that the lipid classes, FA distributions and TAG molecular species of broad beans are not dependent
on the cultivation areas during the growing season. 相似文献
15.
Data on FA contents in the human placenta are limited. Different methods have been used for the FA analysis, and only percentage
results have been presented. We developed and evaluated a method for the determination of FA concentrations in placental tissue.
Lipids were extracted from placental tissue with a chloroform/methanol mixture; and phospholipids (PL), nonesterified FA (NEFA),
TG, and cholesterol esters (CE) were isolated by TLC. Individual lipid fractions were derivatized with methanolic hydrochloric
acid, and the FAME, were quantified by GC with FID. The CV of intra-assay (n=8) of absolute concentrations were evaluated for FA showing a, tissue content >0.01 mg/g. CV ranges were 4.6–11.0% for PL,
6.4–9.3% for NEFA, 6.1–8.9% for TG, and 11.4–16.3% for CE. The relative FA composition across a term placenta indicated no
differences between samples of central and peripheral locations of maternal and fetal site (CV 0.5–9.9%), whereas the absolute
FA concentrations were only reproducible in the PL fraction (CV 7.0–12.8%). The method shows a reasonably high precision that
is well suited for physiological and nutritional studies. 相似文献
16.
A time study of the metabolism of 6,7-14C-retinoic acid after intraperitoneal injection of physiological levels (17 μg, 0.39 μc) into vitamin A deficient rats, which
had been repleted with retinoic acid for two weeks up to two days before injection, resulted in a rapid metabolism to more
polar compounds in the small intestine and its contents and a slower metabolism to primarily different materials in the liver
and kidney. The major route of metabolism resulted in the urinary excretion of 60% of the injected dose in 24 to 27 hr. Urinary
metabolites of 15-14C-retinoic acid were eluted from silicic acid at a similar concentration of solvents as the ring labeled metabolites although
only 32% of the injected dose was recovered in 24 hr. Compounds chromatographically similar to the urinary metabolites were
observed at various times in the liver, kidney and small intestine plus contents in addition to retinoic acid and other metabolites.
The relative amounts of the metabolites in the different tissues studied varied as a function of the tissue and the time of
analysis after injection. Most of the radioactivity from all tissues was extractable into methanol. A liver subcellular distribution
of the radioactivity derived from the intraperitoneal injection of 650 μg of 6,7-14C-retinoic acid (25.9 μc) after 3 hr indicated a minimal level of association of radioactivity (150–250 dpm/mg protein) with
all fractions and a greater association of radioactivity with the lysosomal-microsomal fraction (300–350 dpm/mg protein) and
the 60–100% ammonium sulfate precipitable (750–800 dpm/mg protein) and 100% ammonium sulfate soluble fractions (422 dpm/mg
protein) of the soluble supernatant. 相似文献
17.
Ana C. Lo Prete Clederson H. Dina Carolina H. Azevedo Camila G. Puk Neuza H. M. Lopes Whady A. Hueb Raul Cavalcante Maranhão 《Lipids》2009,44(10):917-924
The exchange of lipids with cells and other lipoproteins is a crucial process in HDL metabolism and for HDL antiatherogenic
function. Here, we tested a practical method to quantify the simultaneous transfer to HDL of phospholipids, free-cholesterol,
esterified cholesterol and triacylglycerols and to verify the lipid transfer in patients with coronary artery disease (CAD)
or undergoing statin treatment. Twenty-eight control subjects without CAD, 27 with CAD and 25 CAD patients under simvastatin
treatment were studied. Plasma samples were incubated with a donor nanoemulsion prepared by ultrasonication of the constituent
lipids and labeled with radioactive lipids; % lipids transferred to HDL were quantified in the HDL-containing supernatant
after chemical precipitation of non-HDL fractions and the nanoemulsion. The assay was precise and reproducible. Increase of
temperature (4–37 °C), of incubation period (5 min to 2 h), of HDL-cholesterol concentration (33–244 mg/dL) and of mass of
nanoemulsion lipids (0.075–0.3 mg/μL) resulted in increased lipid transfer from the nanoemulsion to HDL. In contrast, increasing
pH (6.5–8.5) and albumin concentration (3.5–7.0 g/dL) did not affect lipid transfer. There was no difference between CAD and
control non-CAD with regard to the lipid transfer, but statin treatment reduced the transfer to HDL of all four lipids. The
test herein described is a valid and practical tool for exploring an important aspect of HDL metabolism. 相似文献
18.
Isomeric CLA exhibit several significant biological activities in animals and humans and are easily isomerized to their corresponding
t,t-CLA isomers during methylation with various acid-catalyzed reagents. To minimize such isomerization and provide a valid quantification
of human plasma CLA content, several methylation methods were tested. Plasma neutral lipid, nonesterified FA (NEFA), and polar
lipid classes were separated into the following fractions: (i) cholesteryl ester (CE, 1.2 mg/12 mL, 37.5% lipids), (ii) TAG
(0.8 mg/12 mL, 25% lipids), (iii) NFFA (0.2 mg/12 mL, 6.2% lipids), (iv) MAG/DAG/cholesterol (0.3 mg/12 mL, 9.4% lipids),
and (v) phospholipid (PL, 0.5 mg/20 mL, 15.6% lipids). Data showed that c9,t11-CLA found in TAG, MAG/DAG/cholesterol, and PL fractions were converted to methyl esters with sodium methoxide within 2
h at 55°C. However, the c9,t11-CLA in the CE fraction could not be completely converted to methyl esters by sodium methoxide/acetylchloride in methanol
or methanolic KOH; instead, CE was treated with sodium methoxide and methyl acetate in diethyl ether for 1 h. NEFA were converted
to methyl esters with trimethylsilyldiazomethane (TMSDAM). All reaction mixtures were monitored by TLC prior to GLC analysis.
The highest enrichment of c9,t11-18∶2 (% FA) was in TAG (0.31%), followed by CE (0.14%) and PL (0.13%). The above methylation methods were then applied
to a small subset (n=10) of nonfasting plasma lipid fractions to confirm the applicability of these data. Results from this subset of samples
also indicated that the greatest enrichment of c9,t11-CLA was present in the TAG fraction (0.39%), followed by CE (0.27%) and PL (0.22%). These data indicate that different
plasma fractions have different c9,t11-CLA contents. 相似文献
19.
To identify a stable resource of 20∶4 n−6 (arachidonic acid, AA) in marine fish tissues, the lipid profiles of Siganus fuscescens organs (muscle, liver, and other viscera) and stomach contents were examined throughout the year. Crude total lipid (TL)
contents in respective organs showed seasonal variations and were high in winter and low in summer. The main FA in TL were
16∶0, 18∶0, 16∶1n−7, 18∶1n−9, AA, and 22∶6n−3 (DHA). These FA were those generally observed in marine fish lipids, except
for comparatively high levels of AA. In TL of muscle and liver, AA showed relatively high values during the period from late
May to August (muscle, 4.6–13.1%; liver, 4.5–9.1%), compared with other seasons (muscle, 4.3–9.5%; liver, 3.6–8.4%). The AA
levels in TL of other viscera and stomach contents fluctuated (other viscera, 2.0–10.7%; stomach contents, 7.6–26.7%). Regardless
of the fishing season, each organ contained a higher level of AA in polar lipids (PL) than in neutral lipids. It was concluded
that the fish contain comparatively high levels of AA in their TL throughout the year, and they accumulate AA characteristically
in their tissue PL, probably from dietary food sources. Moreover, it was suggested that S. fuscescens has potential utility as a natural marine source of nutritional lipids, because the fish contain comparatively high levels
of DHA and AA. 相似文献
20.
Guangqi Zheng Changmo Li Lili Guo Wenliang Ruo Shuo Wang 《Journal of the American Oil Chemists' Society》2012,89(4):561-566
The fatty acid (FA) analysis of microalgae Spirulina was studied by applying accelerated solvent extraction (ASE) and followed by purification using solid-phase extraction (SPE).
The objective was to develop a sensitive and reliable purification procedure to remove pigment in lipids co-extracted from
Spirulina. Four extraction solvents were used for the ASE lipids extraction. The extraction efficiency was ranked in the following
order: chloroform:methanol > dichloromethane:methanol > ethanol > hexane. The major composition of fatty acids were examined.
Hexane and chloroform:methanol were compared for the purification step. The amounts of sorbent (Silica gel H), sample, and
the volume of eluent were optimized during SPE procedure. This purification step can successfully remove the pigments from
extracted lipids. For 0.1 g algae sample, chloroform:methanol (2:1, v/v) was the optimal extraction solvent, 0.3 g silica
gel was the optimal amount of sorbent, with 7 mL for the volume of eluent. For hexane as the extraction solvent, 0.5 g algae
sample, 0.3 g silica gel was the optimal amount of sorbent, 5 mL was the optimal volume of eluent. The calibration curve was
produced comprised from five samples that contained FAME concentrations which was ranged from 0.1 to 10 mg/L (R
2 > 0.99). The recoveries of fatty acids were 67.97–134.37%, 74.20–99.13% and 98.34–115.42%, with standard deviations (SD)
of three replicate detections ranged from 1.09 to 8.41%. 相似文献