共查询到20条相似文献,搜索用时 14 毫秒
1.
Trans-6-hexadecenoic acid was found in polar lipids, triglycerides, was esters and diacylglyceryl ethers of the sea anemoneMetridium dianthus from Passamaquoddy Bay. The corresponding alcomaquoddy Bay. The corresponding alcohol also apparently occurs in the wax esters
of this species. The long-chain (C20, C22) monoethylenic alcohols reported for other species of sea anemones from neighboring waters were absent and the major alcohol
and glyceryl ether chain both had 16∶0 structures. The isomers of C18 and C20 monoethylenic fatty acids in polar lipids and triglycerides were unusual in their high proportion of theω
7 isomer. These two lipids also contained higher proportion of the polyunsaturated fatty acids than the others. 相似文献
2.
Robert L. Wolff Dietz Precht Joachim Molkentin 《Journal of the American Oil Chemists' Society》1998,75(6):661-671
This study presents an in-depth, critical survey of the current knowledge about trans- 18:1 acid content and profile in human milk lipids. Emphasis is placed on the analytical methods employed to quantitate
trans- 18:1 acids, most of which lead to imprecise quantitative data. It is demonstrated that data obtained by single gas-liquid
chromatography (GLC) on polar capillary columns are underestimates by 25–40%. Several experiments indicate that the total
content of trans-18:1 acids in human milk is directly related to the quantities ingested the previous day(s), provided no gross weight loss
occurs during breast-milk feeding. Equations have been proposed to describe this relationship, and apparently the percentage
of trans-18:1 isomers, relative to total fatty acids, is approximately three-fourths the quantity (in g) ingested by lactating mothers.
That is, the determination of the trans-18:1 acid percentage in human milk is a convenient means to estimate trans-18:1 acid consumption by corresponding populations. Adapted methods (i.e., silver-ion thin-layer chromatography, coupled
with GLC on long polar capillary columns) allow accurate quantitation of most individual trans- 18:1 acids, more particularly of the trans-Δ16 isomer. This determination, along with a knowledge of the distribution of individual isomers in ruminant fats and partially
hydrogenated oils, is a convenient means to estimate the relative contribution of these two dietary sources to the distribution
of individual trans-18:1 isomers in human milk lipids. A comparison of human milk and infant formulas is made with regard to trans-18:1 acid content and profile. Important differences are noted between data from European countries and from North America. 相似文献
3.
The fatty acid composition, totaltrans content (i.e., sum of all the fatty acids which may have one or moretrans double bonds) and geometric and positional isomer distribution of unsaturated fatty acids of 198 human milk samples collected
in 1992 from nine provinces of Canada were determined using a combination of capillary gas-liquid chromatography and silver
nitrate thin-layer chromatography. The mean totaltrans fatty acid content was 7.19±3.03% of the total milk fatty acids and ranged from 0.10 to 17.15%. Twenty-five of the 198 samples
contained more than 10% totaltrans fatty acids, and thirteen samples contained less than 4%. Totaltrans isomers of linoleic acid were 0.89% of the total milk fatty acids with 18∶2Δ9c, 13t being the most prevalent isomer, followed by 18∶2Δ9c, 12t and 18∶2Δ9t, 12c. Using the totaltrans values in human milk determined in the present study, the intake of totaltrans fatty acids from various dietary sources by Canadian lactating women was estimated to be 10.6±3.7 g/person/d, and in some
individuals, the intake could be as high as 20.3 g/d. The 18∶1trans isomer distribution differed from that of cow's milk fat but was remarkably similar to that in partially hydrogenated soybean
and canola oils, suggesting that partially hydrogenated vegetable oils are the major source of thesetrans fatty acids. 相似文献
4.
Elrobh MS Alanazi MS Khan W Abduljaleel Z Al-Amri A Bazzi MD 《International journal of molecular sciences》2011,12(7):4214-4236
Heat shock proteins are ubiquitous, induced under a number of environmental and metabolic stresses, with highly conserved DNA sequences among mammalian species. Camelus dromedaries (the Arabian camel) domesticated under semi-desert environments, is well adapted to tolerate and survive against severe drought and high temperatures for extended periods. This is the first report of molecular cloning and characterization of full length cDNA of encoding a putative stress-induced heat shock HSPA6 protein (also called HSP70B') from Arabian camel. A full-length cDNA (2417 bp) was obtained by rapid amplification of cDNA ends (RACE) and cloned in pET-b expression vector. The sequence analysis of HSPA6 gene showed 1932 bp-long open reading frame encoding 643 amino acids. The complete cDNA sequence of the Arabian camel HSPA6 gene was submitted to NCBI GeneBank (accession number HQ214118.1). The BLAST analysis indicated that C. dromedaries HSPA6 gene nucleotides shared high similarity (77-91%) with heat shock gene nucleotide of other mammals. The deduced 643 amino acid sequences (accession number ADO12067.1) showed that the predicted protein has an estimated molecular weight of 70.5 kDa with a predicted isoelectric point (pI) of 6.0. The comparative analyses of camel HSPA6 protein sequences with other mammalian heat shock proteins (HSPs) showed high identity (80-94%). Predicted camel HSPA6 protein structure using Protein 3D structural analysis high similarities with human and mouse HSPs. Taken together, this study indicates that the cDNA sequences of HSPA6 gene and its amino acid and protein structure from the Arabian camel are highly conserved and have similarities with other mammalian species. 相似文献
5.
David H. Buss 《Lipids》1969,4(2):152-154
The predominant fatty acids of mature baboon milk were shown by gas-liquid chromatography to be (by weight) palmitic (16%),
oleic (23%), and linoleic (38%) acids. The high proportion of linoleic acid was attributed to the corn oil in the diet. Less
myristic acid (1.3%), but more caprylic (5%) and capric (8%) acids, were present in baboon milk than in human milk. The proportions
of these short-chain fatty acids were highest during early lactation. 相似文献
6.
Milk from 6 species of monkeys contained 2.2–8.5% total lipids, and 11.5–16.5% total solids. The fatty acid composition of
the milks, as determined by an improved gas liquid chromatographic techniques, was generally similar among the six species.
The predominant fatty acids (by wt) were capric (7.5–14.6%), palmitic (19.4–23.3%), oleic (22.4–30.3%), and linoleic (13.6–15.2%).
Small amounts of butyric (0.1–1.2%) and caproic (0.5–0.8%) acids were present in all samples. The averaged data were compared
with the fatty acid compositions of primate and cow milks. Milks of the nonhuman primates contained less myristic, but more
caprylic and capric acids, than did human or cows' milk.
Data taken from thesis of S. Hardjo submitted in partial fulfillment of the requirements for the Masters' degree in food science. 相似文献
7.
The presence oftrans octadecenoic acid isomers was detected and analyzed in 24 hr pooled samples of human milk. Amounts of thetrans isomers of the C18 monoenes ranged from 2% to 4% of the total fatty acids. For purposes of comparison, three commonly used brands of infant
formula were also analyzed and found to contain 0.1% to 1.3% oftrans monoene isomers. Data indicate that breast-fed and bottle-fed infants are receiving minimal levels oftrans fatty acids via milk. 相似文献
8.
9.
Silicic acid column chromatography was used to separate the polar lipids of goats' milk into glycolipid, phosphatidylethanolamine,
phosphatidylserine plus phosphatidylinositol, phosphatidylcholine, and sphingomyelin fractions. Each fraction was purified
by column chromatography and its fatty acid profile determined by gas liquid chromatography and mass spectrometry. The glycerophospholipids
each contained 18∶1 as the predominant fatty acid (∼45%). The sphingolipids contained a high percentage of long-chain saturated
fatty acids (C22 to C24>45%); the glycolipid fraction also contained ca. 2% 2-hydroxy fatty acids. The data represent a comprehensive cross-sectional
study of the major polar lipids found in goats' milks. 相似文献
10.
Thetrans 16∶1, 18∶1 and 18∶2 fatty acid composition of various human organ lipids was studied to determine if isomers accumulated
in specific tissues. “Trans” isomers are defined as those fatty acids containing one or moretrans double bonds. Adipose, kidney, brain, heart and liver tissue lipids were analyzed. Gas chromatography with a 100-SP2560 capillary
column was used to characterize the various positional and/or geometrical isomers. The distribution ofrans 16∶1 and 18∶1 isomers ranged from 0.3% in the brain to 4.0% in adipose tissue, whiletrans 18∶2 isomers ranged from 0.0% in the brain to 0.4% in adipose tissue. Notrans 18∶3 isomers were detected. Positional isomer ratios forcis 16∶1 (Δ9 vs Δ7) andcis 18∶1 (Δ11 vs Δ9) were also determined. Since these ratios are reproducible from one individual to the next, they might be
useful for diagnosis of human metabolic disorders. 相似文献
11.
A. K. Lough 《Lipids》1977,12(1):115-119
In three steers which were given grass silage for six months, the content of phytanic acid (i.e. 3,7,11,15-tetramethylhexadecanoic
acid) in plasma lipid increased to about 8% of the total fatty acids, whereas after this time the proportion in the total
fatty acids of liver and heart lipids was about 1%, and only 0.1% in those of kidney lipids; the acid was present in trace
amounts in adipose-tissue triglycerides and was apparently absent from brain lipids. In eight lactating cows which were given
grass silage for about 3 months, the content of phytanic acid in the total long chain fatty acids of milk and of plasma was
0.7% and 13%, respectively. In the plasma lipids of both steers and lactating cows, phytanic acid constituted a substantial
proportion of the total fatty acids of the triglycerides and phospholipids; the acid was present in lowest proportion in the
cholesteryl esters. 相似文献
12.
Maike Timm‐Heinrich Xuebing Xu Nina Skall Nielsen Charlotte Jacobsen 《European Journal of Lipid Science and Technology》2003,105(8):459-470
Milk drinks containing 5% traditional sunflower oil (SO), randomized lipid (RL) or specific structured lipid (SL) (both produced from SO and tricaprylin/caprylic acid) were compared with respect to their particle size, viscosity and oxidative stability during storage. Furthermore, the effect of adding potential antioxidants EDTA or gallic acid to the milk drink based on SL was investigated. The lipid type significantly affected the oxidative stability of the milk drinks: Milk drink based on SL oxidized faster than milk drink based on RL or SO. The reduced oxidative stability in the SL milk drink could not be ascribed to a single factor, but was most likely influenced by the structure of the lipid and differences in the process applied to produce and purify the lipids. EDTA was a strong antioxidant, while gallic acid did not exert a distinct antioxidative effect in the milk drink based on SL. 相似文献
13.
Mixtures of deuterium-labeledtrans-8-,cis-8- andcis-9-octadecenoic acids (8t–18∶1, 8c–18∶1, 9c–18∶1) were fed as triglycerides (TG) to two adult male subjects. Blood samples
were collected sequentially over a 48-hour period. Plasma and lipoprotein lipids were separated by thin layer chromatography
and analyzed by gas chromatography-mass spectroscopy. Results indicate (i) absorption of the 8t- and 8c–18∶1 isomers were
similar to 9c–18∶1; (ii) the 8t–18∶1 isomer was cleared approximately 30% faster than 9c–18∶1 from plasma TG; (iii) cholesterol
ester samples contained 8.4 times less 8t–18∶1 than 9c–18∶1; (iv) incorporation at the 1-acyl phosphatidylcholine (PC) position
was higher for 8t–18∶1 and 8c–18∶1 (2.2 and 1.7 times) than for 9c–18∶1; and (v) discrimination at the 2-acyl PC position
was 4.6-fold against 8t–18∶1 and 1.3-fold against 8c–18∶1 compared with 9c–18∶1. Discrimination against uptake of the Δ-8
isomers in both neutral and phospholipid classes suggests that both 8t- and 8c–18∶1 may be preferentially oxidized relative
to 9c–18∶1. Except for triglycerides, data for each of the lipid classes from total plasma and individual lipoprotein samples
were similar. These data indicate that differences for incorporation and turnover of the 8t- and 8c–18∶1 isomers relative
to 9c–18∶1 are not substantially influenced by the lipoprotein classes. The maximum isotopic enrichment detected in the chylomicron
triglycerides fractions was 60%, which indicates that a substantial amount of endogenous triglycerides was mobilized during
absorption of the deuterated fats. 相似文献
14.
Carbon nuclear magnetic resonance (13C NMR) methods for determining the composition of cis-/trans- and positional isomers in hydrogenated vegetable oils were developed to reduce analytical time. By selecting appropriate
olefinic carbon peaks and by measuring individual peak areas subsequent to the identification of isomeric peaks on the NMR
spectrum, compositional results of the isomers coincided well with those obtained by conventional gas chromatography (GC).
Therefore, it is highly beneficial to choose the 13C NMR method when analysis time is limited. Though the proposed 13C NMR method is promising, further development is needed. For the time being, combination with the traditional GC method is
still encouraged for precise compositional analysis of cis-/trans- and positional isomers. 相似文献
15.
16.
A representative number of different milk fats based on a wide range of feeding and lactation conditions as well as 123 German margarines, shortenings, cooking and dietetic fats were analyzed for a variety of trans-C18:2 isomers (exhibiting at least one trans double bond) by means of gas chromatography on a 100m Sil 88 capillary column. In milk fats contents of trans Δ9,trans Δ12,cis Δ9,trans Δ13 (+ trans Δ8,cis Δ12),trans Δ8,cis Δ13,cis Δ9,trans Δ12,trans Δ9,cis Δ12 and trans Δ11,cis Δ15 amounted to 0.09%, 0.11%, 0.11%, 0.10%, 0.07% and 0.33% on average and the content of total trans-C18:2 isomers (without cis Δ9, trans Δ11) was 0.99% in the mean. The content of conjugated linoleic acid cis Δ9,trans Δ11 amounted to 0.81% on average in 238 milk fats. In margarine among others the isomers trans Δ9,trans Δ12,cis Δ9,trans Δ13 (+ trans Δ8,cis Δ12), cis Δ9,trans Δ12 and trans Δ9,cis Δ12 were determined and quantified to 0.03%, 0.04%, 0.29% and 0.23% on average. The mean total content of trans-C18:2 isomers in margarines was 0.61%. Moreover, for all trans-C18:2 isomers the frequency distributions as well as the correlation coefficients towards the trans-C18:1 isomers trans Δ6 to trans Δ16 were derived. 相似文献
17.
Nanna Philipson Brandorff 《Lipids》1980,15(4):276-278
During pregnancy and lactation, female rats were fed diets containing either 28% partially hydrogenated marine oil (28MO),
2% arachis oil (2AO), or no fat (FF). Milk lipid composition was examined by gas chromatographic analysis of the gastric content
of 10-day-old suckling pups. An increase to 45% in the milk content of long chain monoenoic acids, 18∶1, 20∶1 and 22∶1, reflects
the fatty acid composition of the marine oil. Milk fatty acids of medium chain length comprised 6%, 31% and 24% of total fatty
acids in the (28MO), (2AO) and (FF) groups, respectively, suggesting that a high-fat diet (28MO) inhibits the lipid synthetic
activity of mammary glands. The amount of dienoic C18-acids (6%) in the group fed (28MO) containing no essential fatty acids (EFA) was similar to the amount of 18∶2 in the group
receiving a low-fat, EFA-rich diet (2AO). However, only half the dienoic acid from the milk of the (28MO)-fed animals was
linoleic acid, which was most likely mobilized from fat depots. 相似文献
18.
Milk lipids, often referred to as “milk fat,” have been of interest to man for centuries. Milk fat is a major component of
bovine milk and most dairy foods and has the highest economic value of any of the milk constituents. In 1970, over 4 billion
pounds of milk fat were produced by 12 million cows in the U.S. Practically all this fat was used in food products and provided
ca. 16% of the total visible and invisible fat consumed by Americans. Although milk fat has been the subject of many investigations
in the past, there is continuing interest in its complex composition and its chemical, physical and nutritional properties.
The purpose of this symposium is to review contemporary knowledge of milk lipids and to focus attention on recent developments
of interest to individuals associated with the field of edible fats and oils.
One of eight papers presented in the symposium “Milk Lipids,” AOCS Meeting, Ottawa, September 1972. 相似文献
19.
Bertschi I Collomb M Rist L Eberhard P Sieber R Bütikofer U Wechsler D Folkers G von Mandach U 《Lipids》2005,40(6):581-587
Consumption of CLA by lactating women affects the composition of their milk, but the pattern of the different CLA isomers
is still unknown. We determined the effects of short maternal supplementation with CLA-rich Alpine butter on the occurrence
of FA and CLA isomers in human milk. In an open randomized controlled study with a two-period cross-over design, milk FA and
CLA isomer concentrations were measured on postpartum days >-20 in two parallel groups of lactating women before, during,
and after consumption of defined quantities of Alpine butter or margarine with comparable fat content (10 d of butter followed
by 10 d of margarine for one group, and vice versa in the other). In the 16 women who completed the study (8/group), Alpine
butter supplementation, increased the C16 and C18 FA, the sum of saturated FA, the 18∶1 trans FA, and the trans FA with CLA. The CLA isomer 18∶2 c9, t11 increased by 19.7%. Significant increases were also found for the isomers t9,t111, t7,c9,t11,c13, and t8,c10 18∶2. The remaining nine of the total 14 detectable isomers showed no changes, and concentrations were <5 mg/100g fat.
A breastfeeding mother can therefore modulate the FA/CLA supply of her child by consuming Alpine butter. Further studies will
show whether human milk containing this FA and CLA isomer pattern acts as a functional food for newborns. 相似文献
20.
The fatty acids of liver lipids from rats raised on a fat free diet from the 30th to the 90th day after birth were analyzed
with special regard to the detection of positional isomers of mono-, di-, tri-, and tetraenoic fatty acids. The methyl esters
obtained after transesterification of total lipids were separated by argentation chromatography into five fractions: I saturated,
II monoenoic, III dienoic, IV dienoic nonmethylene interrupted, V triand tetraenoic fatty acid esters. After hydroxylation
of the double bonds with osmium tetroxide, the analysis of the poly-O-trimethylsilyl derivatives by gas liquid chromatography
on S.C.O.T. columns combined with mass spectrometry revealed the presence of 19 monoenoic, 15 dienoic, and 9 trienoic as well
as 3 tetraenoic fatty acid isomers including the normally occurring representatives of the (n−3), (n−6), (n−7), and (n−9)
fatty acid families. The majority of the identified isomers can be coordinated to one of these families like 7–16∶1; 11–20∶1;
6,9–18∶2; 8,11–20∶2; 5,11–20∶2; 5,8,11–20∶3; 7,10,13–22∶3 to the (n−9) family, 11–18∶1; 13–20∶1; 5,11–18∶2; 7,13–20∶2; 6,11–18∶2;
6,9–16∶2; 8, 11–18∶2; 10,13–20∶2; 5,8,11–18∶3; 7,10,13–20∶3; 4,7,10,13–20∶4 to the (n−7) family and 11,14–20∶2; 5,11,14–20∶3;
6,9,12–18∶3; 8,11,14–20∶3; 5,8,11,14–20∶4; 7,10,13,16–22∶4 to the (n−6) family. All these naturally occuring isomers can be
placed into a network of desaturation and chain elongation steps which allows certain conclusions about the substrate specificity
of the Δ6-, Δ5-and Δ4-desaturase systems. The great number of isomers found in the (n−7) family indicates that the members
of this family are actively metabolized in partial essential fatty acid deficiency. 相似文献