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1.
Although medium-chain FA (MCFA) are mainly absorbed via the portal venous system, they are also incorporated into chylomicron TAG; therefore, the positional distribution of MCFA
in TAG is likely to affect their metabolic fate. We studied chylomicron and VLDL TAG structures, as well as the magnitude
of postprandial lipemia, after two oral fat loads containing decanoic acid (10∶0) predominantly at the sn-1(3),2 (MML) or at the sn-1,3 positions (MLM) of TAG in a randomized, double-blind, crossover clinical trial with 10 healthy, normal-weight volunteers.
An MS-MS method was used to analyze TAG regioisomers. The position of decanoic acid in chylomicron TAG reflected its position
in the TAG ingested, and TAG with none, one, two, or three decanoic acid residues were detected after ingestion of both fats.
More (P<0.05) 30∶0 and 38∶1 TAG (acyl carbons:double bonds) and fewer 46∶5, 54∶5 and 54∶4 TAG were found in chylomicrons after ingestion
of MML than after MLM. The VLDL TAG composition did not differ between the fat loads but did change (P<0.05) 2 to 6 h after ingestion of both fats. No statistical differences were seen between the fat loads in areas under the
plasma, chylomicron, or VLDL TAG response curves or in FFA concentrations. Thus, the positional distribution of MCFA in TAG
affects their metabolic, fate, but the magnitude of postprandial lipemia does not seem to be dependent on the positional distribution
of MCFA in the ingested fat. 相似文献
2.
Alterations in chylomicron and VLDL TAG and the magnitude of postprandial lipemia were studied in healthy volunteers after
two meals of equal FA composition but different TAG-FA positional distribution. Molecular level information of individual
lipoprotein TAG regioisomers was obtained with a tandem MS method. The incremental area under the response curve of VLDL TAG
was large (P=0.021) after modified lard than after lard. In plasma TAG, the difference did not quite reach statistical significance (P=0.086). In general, there were less TAG with palmitic acid in the sn-2 position and more TAG with oleic acid in the sn-2 position in chylomicrons than in fat ingested. From 1.5 to 8 h postprandially, the proportion of individual chylomicron
TAG was constant or influenced by TAG M.W. VLDL TAG regioisomerism was similar regardless of the positional distribution of
fat ingested. Significant alterations were seen in VLDL TAG FA, in M.W. fractions, and in individual regioisomers with respect
to time. The TAG sn-14∶0-18∶1-18∶1+sn-18∶1-18∶1-14∶0, sn-16∶0-16∶1-18∶1+sn-18∶1-16∶1-16∶0, and sn-16∶1-18∶1-18∶1+sn-18∶1-18∶1-16∶1 decreased (P<0.05); and sn-16∶0-16∶0-18∶2+sn-18∶2-16∶0-16∶0, sn-16∶0-16∶0-18∶1+sn-18∶1-16∶0-16∶0, sn-16∶0-18∶1-16∶0, and sn-16∶0-18∶1-18∶2+sn-18∶2-18∶1-16∶0 increased (P<0.05) after both meals. In conclusion, positional distribution of TAG FA was found to affect postprandial lipid metabolism
in healthy normolipidemic subjects. 相似文献
3.
Effects of dietary triacylglycerol structure on triacylglycerols of resultant chylomicrons from fish oil- and seal oil-fed rats 总被引:3,自引:0,他引:3
We investigated the influence of the intramolecular fatty acid distribution of dietary triacyl-sn-glycerols (TAG) rich in n-3 polyunsaturated fatty acids (PUFA) on the structure of chylomicron TAG. Fish oil and seal oil,
comparable in fatty acid compositions but with different contents of major n-3 PUFA esterified at thesn-2 position (20:5n-3, 46.6%, and 5.3%; 22:6n-3, 75.5%, and 3.8%, respectively), were fed to rats. Mesenteric lymph was collected
and the chylomicrons were isolated by ultracentrifugation. The fatty acid composition of chylomicrons largely reflected the
fatty acid composition of the oils administered. The intramolecular fatty acid distributions of the TAG fed were reflected
in the chylomicron TAG as the fraction of the total contents observed in thesn-2 position of 20:5n-3 were 23.6 and 13.3%, and of 22:6n-3 were 30.6 and 5.4% for resultant chylomicrons following fish oil
and seal oil administration, respectively. Thus, after seal oil administration, significant higher load of n-3 PUFA was esterified
in thesn-1,3 positions of chylomicron TAG compared with fish oil administration (P<0.05). 相似文献
4.
The effect of dietary TAG structure and fatty acid acyl TAG position on palmitic and linoleic acid metabolism was investigated
in four middle-aged male subjects. The study design consisted of feeding diets containing 61 g/d of native lard (NL) or randomized
lard (RL) for 28 d. Subjects then received an oral dose of either 1,3-tetradeuteriopalmitoyl-2-dideuteriolinoleoyl-rac-glycerol or a mixture of 1,3-dideuteriolinoleoyl-2-tetradeuteriopalmitoyl-rac-glycerol and 1,3-hexadeuteriopalmitoyl-2-tetradeuteriolinoleoyl-rac-glycerol. Methyl esters of plasma lipids isolated from blood samples drawn over a 2-d period were analyzed by GC-MS. Results
showed that absorption of the 2H-fatty acids (2H-FA) was not influenced by TAG position. The 2H-FA at the 2-acyl TAG position were 85±4.6% retained after absorption. Substantial migration of 2H-16∶0 (31.2±8.6%) from the sn-2 TAG position to the sn-1,3 position and 2H-18∶2n−6 (52.8±6.4%) from the sn-1,3 position to the sn-2 position of chylomicron TAG occurred after initial absorption and indicates the presence of a previously unrecognized isomerization
mechanism. Incorporation and turnover of the 2H-FA in chylomicron TAG, plasma TAG, and plasma cholesterol esters were not influenced by TAG acyl position. Accretion of
2H-16∶0 from the sn-2 TAG position in 1-acylphosphatidylcholine was 1.7 times higher than 2H-16∶0 from the sn-1,3 TAG positions. Acyl TAG position did not influence 2H-18∶2n−6 incorporation in PC. The concentration of 2H-18∶2n−6-derived 2H-20∶4n−6 in plasma PC from subjects fed, the RL diet was 1.5 times higher than for subjects fed the NL diet, and this result
suggests that diets containing 16∶0 located at the sn-2 TAG position may inhibit 20∶4n−6 synthesis. The overall conclusion is that selective rearrangement of chylomicron TAG structures
diminishes but does not totally eliminate the metabolic and physiological effects of dietary TAG structure. 相似文献
5.
S. Kermasha S. Kubow M. Safari A. Reid 《Journal of the American Oil Chemists' Society》1993,70(2):169-173
Triacylglycerol (TAG) standards were separated by analytical high-performance liquid chromatography (HPLC) with laser light-scattering
detection (LLSD). A high sensitivity for TAGs was observed with LLSD whereas poor sensitivity was observed with ultraviolet
detection. The HPLC-LLSD analytical separation of butterfat TAGs showed that the TAGs were eluted according to increasing
carbon number. Preparative HPLC-LLSD was used to characterize butterfat TAGs that contained hypercholesterolemic fatty acids
(laurate, myristate, palmitate) with carbon chainlengths of 12 or greater. These TAG fractions accounted for 29.2% of the
total butterfat TAGs. Analysis of the positional distribution of fatty acids of selected butterfat TAGs containing hypercholesterolemic
fatty acids showed the presence of positional isomers in each of these fractions. These butterfat TAGs also showed the predominant
presence of hypercholesterolemic fatty acids at thesn-2 position. The characterization of the positional distribution of hypercholesterolemic fatty acids in butterfat TAGs is
the first step for the determination of the metabolic role of the positional distribution in the hypercholesterolemic effects
of butter. 相似文献
6.
Fourteen healthy male volunteers were given two separate high-saturated-fat meals with and without the addition of 4 g highly
purified ethyl esters of either eicosapentaenoic acid (EPA) (95% pure, n=7) or docosahexaenoic acid (DHA) (90% pure, n=7) supplied as 1-g capsules each containing 3.4 mg vitamin F. The chylomicrons were isolated 6 h after the meals, at peak concentrations
of n−3 fatty acids (FA). Addition of n−3 FA with the meal caused a 10.4-fold increase in the concentration of n−3 FA in chylomicrons
compared to the saturated fat meal without addition of n−3 FA. After the saturated-fat meal, the concentration of thiobarbituric
acid-reactive substances (TBARS) was 327.6±34.6 nmol/mmol triacylglycerol (TAG), which increased to 1015.8±212.0 nmol/mmol
TAG (P<0.0001, n=14) after EPA and DHA were added to the meal. There was no significant correlation between the concentrations of TBARS and
vitamin E in the chylomicrons collected 6 h after the test meal. The present findings demonstrate an immediate increase in
chylomicron peroxidation ex vivo provided by intake of highly purified n−3 FA. The capsular content of vitamin E was absorbed into chylomicrons, but the amount
of vitamin E was apparently not sufficient to protect chylomicrons against lipid peroxidation ex vivo. Daily intake of 4 g n−3 FA either as EPA or DHA for 5 wk did not change the plasma concentration of TBARS. Although not
significantly different between groups, DHA supplementation decreased total glutathione in plasma (P<0.05) and EPA supplementation increased plasma concentration of vitamin E (P<0.05). The other lipid-soluble and polar antioxidants in plasma remained unchanged during 5 wk of intervention with highly
purified n−3 FA. 相似文献
7.
Heikki Kallio Kati Korkiasaari Olli Sjövall Jukka-Pekka Suomela Kaisa Linderborg 《Journal of the American Oil Chemists' Society》2006,83(5):407-413
TAG of butterfat were fractionated according to the type and degree of unsaturation into six fractions by silver-ion HPLC.
The fractions containing TAG with either cis-or trans-monoenoic FA were collected and fractionated further by reversed-phase HPLC to obtain fractions containing cis TAG of ACN:DB (acyl carbon number:double bonds) 48∶1, 50∶1, and 52∶1 as well as trans 48∶1, 50∶1, and 52∶1. The FA compositions of these fractions were elucidated by GC. The MW distribution of each fraction
was determined by ammonia negative-ion CI-MS. Each of the [M-H]− parent ions was fractionated further by collision-induced dissociation with argon, which gave information on the location
of cis-and trans-FA between the primary and secondary positions of TAG. The results suggest that the sn-positions of the monoenoic cis-and trans-FA depend on the two other FA present in the molecule. With 14∶0 FA in the TAG molecule, the 18∶1 FA in the sn-2 position are mostly present as cis-isomers. When there is no 14∶0 in the TAG molecule, the trans-18∶1 isomers seem to be more common in the sn-2 position. Also when other long-chain FA are present, the trans-isomers are more likely to be located in the secondary (sn-2) position. 相似文献
8.
This study uses normal-phase HPLC with on-line positive ion electrospray mass spectrometry (ESI-MS) to obtain quantitative
compositional data on both synthetic and butterfat short-chain TAG. The product ion tandem MS of standards averaged 11.1 times
lower in abundance of the ion formed by cleavage of FA from the sn-2-position for the pairs of regioisomers in the TAG classes: L/L/S-L/S/L and L/S/S-S/L/S, where L denotes long and S short
acyl chain (C2−C6). The molar correction factors, determined for 42 regioisomeric pairs of short-chain TAG of 20 randomized mixture of standards,
differed by 1.4–80% as the ratios varied between 0.217 and 5.847. Butterfat TAG were resolved into four fractions on short
flash chromatography grade silica gel columns. Pairs of regioisomers in the TAG classes L/S/S-S/L/S with predominance of L/S/S
isomers and the sole regioisomers in the TAG classes L/L(M)/S were identified by tandem MS, where M denotes either 8∶0 or
10∶0 acyl chain. The total proportion of L/L(M)/S isomers was estimated at 34.7 and that of L/S/S-S/L/S at 1.0 mol%, including
a small proportion of S/S/S. In contrast to previous work, the present data indicate the presence of a small proportion of
butyric and caproic acids in the sn-1-position. The overall distribution of the FA in the short-chain TAG of butterfat, calculated from direct MS measurements,
was consistent with the results of indirect determinations based on stereospecific analyses of total butterfat. 相似文献
9.
Interesterification or the randomization reaction changes fatty acid positional distribution and solid fat content of fats, which may consequently affect fat absorption and metabolism. It is well established that saturated fatty acids in the sn‐2 position of triacylglycerols (TAG) have better digestibility and lower postprandial chylomicron clearance compared to those in the sn‐1,3 positions in animal experiments. TAG structure is also shown to affect fasting lipid level and atherosclerosis in animals, but fat interesterification it has been shown to not affect fasting lipid level in human adults. However, its effect on postprandial responses is controversial. In this review, the complex results of studies of interesterification and lipemia were briefly discussed. More importantly, the confounding of two factors that are both changed by interesterification, TAG structure and solid fat content as the main limitation on understanding how interesterification affects lipemia is emphasized. Separation of the two factors is possible using paired fats as demonstrated. This paper also discusses some intriguing effects of fats having saturated fatty acids in the sn‐2 position and the need for future research. 相似文献
10.
Chylomicrons transport absorbed fat from the intestine to the circulation. During dietary fat absorption, the chylomicrons
become larger in diameter, and in some studies an increase in chylomicron number has been observed as well. In the present
study, we compared particle size and number in rat lymph following administration of four different oils. We administered
fish oil, medium-chain TAG (MCT), and two structured oils differing in intramolecular structure, with either medium-chain
FA in the outer positions of the TAG and long-chain n−3 PUFA in the sn-2 position (MLM oil) or with the reverse structure (LML oil), to lymph-cannulated rats and collected lymph in fractions for
the following 8 h. Chylomicron size was measured by a particle size analyzer immediately after collection, and from these
data the number of chylomicrons present was estimated. The number of particles in lymph increased during the absorption of
oils containing long-chain PUFA (MLM, LML, and fish oil), whereas it was not affected by administration of MCT. The FA from
MCT were probably absorbed via the portal vein; therefore, only a small number of particles were measured in lymph. When comparing the two structured oils,
we observed a tendency toward a higher number of particles after LML administration, although the difference was not statistically
significant. The highest number of particles after administration of all oils was observed in the size intervals 53–80 and
80–121 nm and probably represented small chylomicrons. Thus, the FA composition influenced the number of particles in lymph
during absorption, whereas TAG structure had only a minor influence. 相似文献
11.
The FA composition in the sn-2 position of TAG is routinely determined after porcine pancreatic lipase hydrolysis. However, the content of saturated FA
increased when a pancreatic lipase preparation with higher specific activity was used. Lipase from Rhizopus delemar was selected as a potential replacement lipase for the following reasons: (i) The FA specificity is nearly equivalent in
hydrolysis activity toward FA such as lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic, and α-linolenic acids;
and (ii) lipase from R. delemar hydrolyzes fatty acyl residues at the sn-1,3 positions of TAG. Acyl migration products were present at less than 0.8% in lipase hydrolysates containing 6–14% of sn-2 MAG. A reproducibility CV of less than 5% was obtained in a collaborative study in which the compositions of the main FA
at the sn-2 position in olive oil were determined using lipase from R. delemar.
This article was presented in part at the Biocatalysis Symposium, 94th AOCS Annual Meeting & Expo, Kansas City, Missouri,
May 2003. 相似文献
12.
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
13.
Marine lipid-based liposomes increase <Emphasis Type="Italic">in vivo</Emphasis> FA bioavailability 总被引:1,自引:0,他引:1
Liposomes made from an extract of natural marine lipids and containing a high n-3 PUFA lipid ratio were envisaged as oral
route vectors for FA supplements in order to increase PUFA bioavailability. The absorption of FA in thoracic lymph duct-cannulated
rats, after intragastric feeding of dietary fats in the form of liposomes or fish oil, was compared. Lipid and FA analyses
were also performed on feces. Five mole percent α-tocopherol was added to fish oil and incorporated into the liposome membrane.
The influence of α-tocopherol on FA lymph recovery was also investigated. In vivo, FA absorption in rats was favored by liposomes (98±1%) compared to fish oil (73±6%). In the same way, the DHA proportion
in lymph was higher after liposome ingestion (78%) than after fish oil ingestion (47%). However, phospholipid (PL) concentration
in lymph was not affected by the kind of dietary fat ingested, suggesting a PL regulation due to de novo TAG synthesis. The influence of the intramolecular distribution of n-3 PUFA in dietary lipids (TAG and PL) on the intramolecular
FA distribution in TAG of chylomicrons was also investigated. The results obtained showed that the distribution of n-3 PUFA
esterified on the sn-2 of chylomicron TAG depended on the lipid source administered. All these results correlated, at least partly, with in vitro liposome behavior under conditions that mimic those of the gastrointestinal tract. As a whole, this study pointed out that
marine PL may constitute an attractive material for the development of liposomes as oral PUFA supplements. 相似文献
14.
Cam‐Chi Ngo‐Duy Frédéric Destaillats Marjo Keskitalo Joseph Arul Paul Angers 《European Journal of Lipid Science and Technology》2009,111(2):164-169
Oils from the seeds of caraway (Carum carvi), carrot (Daucus carota), celery (Apium graveolens) and parsley (Petroselinum crispum), all from the Apiaceae family, were analyzed by gas chromatography for their triacylglycerol (TAG) composition and fatty acid (FA) distribution between the sn‐1(3) and sn‐2 positions of TAG. Twenty‐two TAG species were quantified. Glyceryl tripetroselinate was the major TAG species in seed oils of carrot, celery and parsley, with levels ranging from 38.7 to 55.3%. In caraway seed oil, dipetroselinoyllinoleoylglycerol was the major TAG species at 21.2%, while the glyceryl tripetroselinate content was 11.4%. Other TAG species were linoleoyloleoylpetroselinoylglycerol and dipetroselinoyloleoylglycerol. Predominantly, TAG were triunsaturated (72.2–84.0%) with diunsaturates at 14.4–25.9%, and small amounts of monounsaturated TAG. Results for regiospecific analysis showed a non‐random FA distribution in Apiaceae for palmitic, petroselinic, linoleic and oleic acids. Petroselinic acid was predominantly located at the sn‐1(3) position in carrot, celery and parsley seed oils, while it was mainly at the sn‐2 position in caraway seed oil. The distribution of linoleic acid was opposite to that of petroselinic acid. Oleic acid was mostly located at the sn‐2 position, except for caraway, where it was evenly distributed between the sn‐1(3) and sn‐2 positions. Both the saturated FA, palmitic and stearic acid, were located mainly at the sn‐1(3) position. The presence of a high level of tripetroselinin in parsley seed oil (55.3%) makes it a potential source for the production of petroselinic acid. 相似文献
15.
Roman A. Sidorov Vasily P. Pchelkin Anatoly V. Zhukov Andrei G. Vereshchagin Vladimir D. Tsydendambaev 《Journal of the American Oil Chemists' Society》2014,91(12):2053-2063
Positional‐species composition (PSC) of 1,2,3‐triacyl‐sn‐glycerols (TAG) from the arils of mature fruits of 13 species of Euonymus L. genus was established. The residues of six major fatty acids (FA), palmitic, stearic, hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic, were present in the TAG. PSC of TAG was determined by their partial lipase hydrolysis. By using hierarchical cluster and principal component analyses, it was definitely demonstrated that separate taxonomic units forming this genus were significantly distinguished as regards PSC of TAG. In particular, the Euonymus subgenus greatly exceeded the Kalonymus subgenus in both total content of L in TAG and in the rate of its incorporation into their mid‐position, while TAG of Kalonymus were marked by a prevalence of O‐TAG and sn‐2‐O isomers. Thus, these subgenera were significantly distinct in the rate of incorporation of O and L residues in the sn‐2 position of TAG molecules. Meanwhile, the TAG from the Euonymus section species were marked by an enhanced concentration of H and the incorporation of H in UUU TAG was much more active than in other TAG types. As for positional‐type composition of TAG, saturated FA were always virtually absent in the sn‐2 position of Euonymus aril TAG. 相似文献
16.
Stereospecific analysis was carried out to establish positional distribution of FA in the TAG of DHA, EPA, and (EPA+DHA)-enriched
oils. In this study, TAG of enzymatically modified oils were purified using a silicic acid column. The TAG were then subjected
to positional distribution analysis using a modified procedure involving reductive cleavage with Grignard reagent. The results
showed that in DHA-enriched borage oil (BO), DHA was randomly distributed over the three positions of TAG, whereas γ-linolenic
acid (GLA) was mainly esterified at the sn-2 and-3 positions. In DHA-enriched evening primrose oil (EPO), however, DHA and GLA were concentrated in the sn-2 position. In EPA-enriched BO, EPA was randomly distributed over the three positions of TAG, similar to that observed for
DHA. In EPA-enriched EPO, however, this FA was mainly located at the primary positions (sn-1 and sn-3) of TAG. In both oils, GLA was preferentially esterified at the sn-2 position. In (EPA+DHA)-enriched BO, EPA and DHA were mainly esterified at the sn-1 and -3 positions of TAG, whereas GLA was mainly located at the sn-2 position. In (EPA+DHA)-enriched EPO, GLA was mainly located at the sn-2 and-3 positions; EPA was preferentially esterified at the sn-1 and-3 positions, and DHA was found mainly at the sn-3 position. 相似文献
17.
Ratios of Regioisomers of the Molecular Species of Triacylglycerols in Lesquerella (Physaria fendleri) Oil Estimated by Mass Spectrometry 下载免费PDF全文
Jiann-Tsyh Lin Clifton K. Fagerquist Grace Q. Chen 《Journal of the American Oil Chemists' Society》2016,93(2):183-191
The ratios of regioisomers of 72 molecular species of triacylglycerols (TAG) in lesquerella oil were estimated using the electrospray ionization mass spectrometry of the lithium adducts of TAG in the HPLC fractions of lesquerella oil. The ratios of ion signal intensities (or relative abundances) of the fragment ions from the neutral losses of fatty acids (FA) as α‐lactones at the sn‐2 position (MS3) of the molecular species of TAG were used as the ratios of the regioisomers. The order of the preference of FA incorporation at the sn‐2 position of the molecular species of TAG in lesquerella was as: normal FA > OH18 (monohydroxy FA with 18 carbon atoms) > diOH18 > OH20 > diOH20, while in castor was as: normal FA > OH18 > OH20 > diOH18 > triOH18. Elongation (from C18 to C20) was more effective than hydroxylation in lesquerella to incorporate hydroxy FA at the sn‐1/3 positions. The block of elongation in lesquerella may be used to increase the content of hydroxy FA, e.g., ricinoleate, at the sn‐2 position of TAG and to produce triricinolein (or castor oil) for industrial uses. The content of normal FA at the sn‐2 position was about 95 %, mainly oleate (38 %), linolenate (31 %) and linoleate (23 %). This high normal FA content (95 %) at the sn‐2 position was a big space for the replacement of ricinoleate to increase the hydroxy FA content in lesquerella oil. The content of hydroxy FA at the sn‐1/3 positions was 91 % mainly lesquerolic acid (85 %) and the content of normal FA was 6.7 % at the sn‐1/3 position in lesquerella oil. 相似文献
18.
Structured TAG (STAG) containing medium-chain FA (MCFA) in the sn-1,3 positions and essential FA in the sn-2 position were synthesized by lipase-catalyzed acidolysis. In our previous studies we found that part of the MCFA from STAG
could be absorbed in the small intestine; however, it was unclear how they were absorbed. In order to get a better understanding
of the metabolism of STAG to improve future design and application of STAG, in the present study lymph lipids collected after
feeding STAG were fractionated into different classes and the FA composition of each lipid class was studied by GC after methylation
to FAME. Caprylic acid was detected in the fraction of TAG only after administration of 1,3-dioctanoyl-2-linoleyl-sn-glycerol (8∶0/18∶2/8∶0), whereas lauric acid was detected in TAG, DAG, and FFA as well as phospholipids after administration
of 1,3-didodecanoyl-2-linoleyl-sn-glycerol (12∶0/18∶2/12∶0). We conclude that the enterocyte has the ability to reacylate the MCFA into TAG and that the intestinal
absorption of MCFA from STAG mainly occurs by resynthesis of TAG. Caprylic acid from STAG is not incorporated into phospholipids,
whereas lauric acid from STAG can be incorporated into phospholipids. 相似文献
19.
Here, we report the identification and quantification of the molecular species of long-, medium-, and short-chain triacylglycerols
(TAG) in butterfat (BF), including TAG with an odd number of acyl carbons (ACN) and TAG with unidentified molecular species.
In the present study, in addition to auto-MS2, a large number of methods, each recording MS2 for 1–4 ions, were used for identification of TAG species. For the quantification of long-chain, odd ACN TAG, and TAG with
unidentified molecular species, molar correction factors (MCF) were calculated from the uncorrected mol% (area mol%) of each
ACN:DB (number of double bonds) class in randomized butterfat (RBF), and the respective mol% in the calculated random composition
of RBF. The butyrate, caproate, and medium-chain (C8, C10) TAG were quantified using regio- or acyl-chain-specific MCF calculated from their area mol% in RBF and mol% in the calculated
random composition. These methods enabled us to identify ca. 450 TAG species in 184 quantified peaks of 88 ACN:DB classes.
The proportions of saturated, monoene, diene, triene, tetraene, pentaene, and hexaene TAG were 40.0, 38.4, 16.2, 4.5, 0.6,
0.1, and 0.03 mol%, respectively. The proportions of TAG with not identified molecular species and odd ACN TAG were 11.8 and
5.7 mol%, respectively. The most abundant short-chain TAG species were butyroyldipalmitoylglycerol + butyroylmyristoylstearoylglycerol
(5.25 mol%) and butyroylpalmitoyloleoylglycerol (4.08 mol%). 相似文献
20.
Information obtained in recent years regarding the enzymes involved in FA synthesis can now be applied to develop novel sunflower
lines by incorporating enzymes with specific characteristics into lines with a defined background. We have generated three
highly saturated mutant lines in this way and characterized their FA content. The new high-palmitic, low-palmitoleic lines
CAS-18 and CAS-25, the latter on a high-oleic background, have been selected from the high-stearic mutant CAS-3 by introducing
a deficient stearic acid desaturase in a high-palmitic background from the previously developed mutant lines CAS-5 and CAS-12,
respectively. As such, the desaturation of palmitic acid and the synthesis of palmitoleic acid and its derivatives (asclepic
and palmitolinoleic acids) were reduced in these high-palmitic lines, increasing the stearic acid content. Likewise, introducing
a FA thioesterase from a high-palmitic line (e.g., CAS-5) into the high-stearic CAS-3 increased the stearic acid content from
27 to 32% in the new high-stearic line CAS-31. As previously described in high-palmitic lines, high growth temperatures did
not reduce the linoleic acid content of the oil. Furthermore, the FA composition of TAG, DAG, and phospholipids was modified
in these lines. Besides a high degree of saturation, the TAG from these new vegetable oils have a low content of saturated
FA in the sn-2 position. The α asymmetric coefficient obtained also indicates that the saturated FA are asymmetrically distributed within
the TAG molecules. Indeed, the disaturated TAG content rose from 31.8 to 48.2%. These values of disaturated TAG are the highest
to date in a temperate oilseed. 相似文献