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1.
A cell-free plant system was developed generating short-chain volatile hydrocarbons as markers of light-induced copper-mediated
peroxidation of fatty acids present either as endogenous constituents of photosynthetic membranes or added exogenously. Different
polyunsaturated fatty acids are present in the blue green algaeAnacystis nidulans, Anabaena variabilis andSpirulina platensis. The first species has no polyunsaturated acids. Thylakoids isolated from these algae produce different short-chain volatile
hydrocarbons. The location of the double bond of dienoic or higher polyunsaturated fatty acids most distant from the carboxyl
group determines the chain length of hydrocarbons evolved. Their number of C-atoms is the same as found beyond this double
bond of the fatty-acid molecule (ω-1). This pattern of volatile hydrocarbons produced is in contrast to thermolytic cleavage.
Malondialdehyde is formed only when at least 3 double bonds are present in the fatty acid. Peroxidation of endogenous thylakoidal
and added fatty acids is completed within 24 hr; a maximum of 1% of the carbon skeleton can be recovered as volatile hydrocarbons. 相似文献
2.
P. W. Parodi 《Journal of the American Oil Chemists' Society》1976,53(8):530-534
Samples of polyunsaturated margarines, table margarines, hard cube polyunsaturated vegetable oil, hard cube vegetable oil,
animal fat, and blends of vegetable oil and animal fat were analyzed for fatty acid composition, percentage ofcis,cis-methylene interrupted polyunsaturated fatty acids, percentage isolatedtrans-unsaturation, and percentage conjugated diene. Gas liquid chromatography was used to separate and measure the geometric isomers
of the octadecaenoic and octadecadienoic acids. Selected samples were analyzed for the content of positional isomers in theircis monoene andtrans monoene fractions, and for the percentage of fatty acid esterified in the 2-position of their triglycerides. 相似文献
3.
Results of analytical studies on the composition of 10 selected margarines representative of consumeravailable hard and soft
types are presented. Paired hard and soft products from the same manufacturer were chosen where possible. All of the margarines
were compared on the basis of total fatty acid composition, polyunsaturated to saturated fatty acid ratios, totaltrans and thetrans content of the monoene and diene fractions, location of the double bond in the monoene isomers, per cent conjugation, distribution
of the fatty acids at the 2 position of the triglycerides, tocopherol content, and the ratios of α-tocopherol to polyunsaturated
fatty acids. As expected the soft margarines contained more polyunsaturated fatty acids than their companion hard types, but
all soft margarines did not contain more polyunsaturated fatty acids than all of the hard margarines. The one margarine containing
safflower oil had the highest polyunsaturated to saturated ratio. Eight of the ten margarines contained more than 15%trans monoene and nine contained less than 5%trans diene. Positional isomers in the monoene fraction were Δ6 toΔ12 with thecis Δ9 isomer predominating. All of the margarines contained less than 1.9% conjugation. The percentage oftrans monoene at the 2 position was greater for some margarines than that in the total fatty acid. This was attributed to the preferential
placement of polyunsaturated fatty acids at the 2 position in the original vegetable oils. The forms of tocopherol found were
characteristic of the original vegetable oils. Ratios of α-tocopherol to PUFA varied from 0.1 to 0.5 mg/g. Determination of
the relationship of the amount of tocopherol content to either source or hardness is not possible on the basis of our data. 相似文献
4.
Menhaden oil (MO) and partially hydrogenated menhaden oil (PHMO) were dry-fractionated and solvent-fractionated from acetone.
After conversion to fatty acid methyl esters, the compositional distribution of saturated, monounsaturated, trans, and n−3 polyunsaturated fatty acids (PUFA) in the isolated fractions was determined by gas chromatography. Acetone fractionation
of MO at −38°C significantly increased the n−3 PUFA content in the liquid fractions over that of starting MO (P<0.05). For PHMO, liquid fractions obtained by low-temperature crystallization (−38, −18, and 0°C) from acetone showed significant
increases (P<0.05) in monounsaturated fatty acid (MUFA) content over that of the starting PHMO. For selected MUFA-enriched fractions,
reversed-phase high-performance liquid chromatography (HPLC) was used to separate, isolate, and characterize the major triacylglycerol
(TAG) molecular species present. Thermal crystallization patterns for these fractions also were determined by differential
scanning calorimetry (DSC). The results demonstrated that under the appropriate conditions it is possible to dry-fractionate
or solvent-fractionate MO and PHMO into various solid and liquid fractions that are enriched in either saturated, monounsaturated,
polyunsaturated, or the n−3 classes of fatty acids. Moreover, characterization of these TAG fractions by reversed-phase HPLC
gives insight into the compositional nature of the TAG that are concentrated into the various fractions produced by these
fractionation processes. Finally, the DSC crystallization patterns for the fractions in conjunction with their fatty acid
compositional data allow for the optimization of the fractionation schemes developed in this study. This information allows
for the production of specific TAG fractions from MO and PHMO that are potentially useful as functional lipid products. 相似文献
5.
P. K. Pal D. K. Bhattacharyya S. Ghosh 《Journal of the American Oil Chemists' Society》2001,78(1):31-36
This work primarily aims to further modify the stearin fractions, obtained from anhydrous milk fat, after fractionation by
dry process and by solvent process using isopropanol, for extending their scope of utilization in edible fat products. Butter
stearin fractions, on blending with liquid oils like sunflower oil and soybean oil in different proportions, offer nutritionally
important fat products with enriched content of essential fatty acids like C18∶2 and C18∶3. The butter stearin fraction from isopropanol fractionation, when interesterified with individual liquid oils by Mucor miehei lipase as a catalyst, yields fat products having desirable properties in making melange spread fat products with reasonable
content of polyunsaturated fatty acids and almost zero trans fatty acid content. 相似文献
6.
Summary A scheme is described to separate the fatty acids of shortenings and margarines into four fractions, the final filtrate of
which contains most of the polyunsaturated acids. The nature of the unsaturated acids in these fractions is discussed. It
is observed that these fats contain 25–40% oftrans monoethenoic acids and 2–8% of linoleic acid and considerable proportions of both 9,12-cis, trans ortrans,cis and isolatedcis,trans isomers of linoleic acid.
This work was supported in part from funds granted by the Ohio State University Research Foundation to the university for
aid in fundamental research. 相似文献
7.
Lipid peroxidationin vivo 总被引:3,自引:0,他引:3
Lloyd A. Witting 《Journal of the American Oil Chemists' Society》1965,42(11):908-913
Under a rather rigidly defined set of empirical conditions, the kinetics of production of a specific tocopherol-deficiency
sign, creatinuria, in the rat were comparable to the kinetics of the autoxidation of pure polyunsaturated fatty acids in model
systemsin vitro. The tocopherol requirement of the rat under these conditions was clearly related to the kinetics of lipid peroxidation.
Dietary, biologically available selenium decreased the rate of production of creatinuria and the rate of disappearance of
tissue polyunsaturated fatty acids (PUFA) equally and, therefore, may have functioned as a lipid antioxidantin vivo. A hypothetical model of lipid peroxidation was prepared in an attempt to describe the interaction of PUFA, tocopherol, biologically
available selenium, and sulfur amino acids.
Presented in part at the AOCS meeting in Chicago, Ill., October, 1964. 相似文献
8.
The positional distribution of fatty acids has been determined for the milk triacylglycerols of the Antarctic fur seal,Arctocephalus gazella. Of particular interest was the positional distribution of the polyunsaturated n−3 fatty acids in milk triacylglycerols (TG).
In adipocytes of pinnipeds, TG are synthesized with the n−3 fatty acids primarily in thesn-1,3 positions. To determine the positional distribution, extracts of enzymatically digested lipids were separated by thin-layer
chromatography, and the constituent fatty acids were separated and quantified by gas-liquid chromatography. Monoenoic and
saturated fatty acids comprised over 75% of the total, the ratio of monoenoic to saturated fatty acids being 2∶1. The percent
content of the long-chain n−3 fatty acids, 20∶5, 22∶5 and 22∶6, ranged between 15–20%. The positional analyses revealed that
at thesn-2 position of milk TG, saturated fatty acids were in excess (57%), and the content of n−3 fatty acids was less than 5%. More
than 80% of the n−3 fatty acids in milk were located in thesn-1,3 positions. The data indicate that in pinnipeds TG are synthesized in the mammary gland and adipose tissue with fatty
acids having similar positional distributions. 相似文献
9.
J. W. Farquhar 《Journal of the American Oil Chemists' Society》1965,42(7):615-616
Lecithins (separated on basic silicic acid columns) were obtained from humans fed three different diets: eitherad-libitum or diets containing 40% of calories from linoleic acid (as corn oil) or from oleic acid (as triolein). Four lecithin subfractions
were studied from each dietary group. Lecithin fractions eluting earliest (and apparently the least polar) contained the highest
molar ratios of unsaturated fatty acids and the highest proportion of C-20 to C-22 polyunsaturated fatty acids. A slight increase
in proportions of diunsaturated molecules occurred in corn oil and triolein groups. However, over 90% of lecithins of each
dietary group were maintained as themonosaturated - monounsaturated type. Therefore, in contrast to human adipose tissue triglycerides, the saturated/unsaturated fatty acid ratio of lecithins
of the erythrocyte membrane is largely unaffected by immense increases in dietary unsaturated fatty acid. Major shifts of
oleic and linoleic acid occurred but proportions were unaltered of longer chain length (>C-18) polyunsaturated fatty acids.
The relevance of these findings to membrane structure and function and to glycerophosphatide biosynthesis is discussed. 相似文献
10.
Fatty acids of Ophiuroidea (brittle star) Ophiura sarsi have been investigated by gas-liquid chromatography (GLC). About 2–13% of four unidentified fatty acids were found in total
fatty acids from a sample caught at a depth of 1,100 m. Structural analyses were undertaken after partial hydrogenation of
their concentrates with hydrazine hydrate and subsequent isolation of the monoenoate products by argentation thin-layer chromatography.
The structures of the unidentified fatty acids were determined as 7E,13E-eicosadienoic (20∶2), 7E,13E,17Z-eicosatrienoic (20∶3), 9E,15E,19Z-docosatrienoic (22∶3), and 4Z,9E,15E,19Z-docosatetraenoic (22∶4) acids by gas chromatography-mass spectrometry of dimethyl disulfide adducts and GLC of the monoenoates
on a polar column. These fatty acids belong to a family of nonmethylene-interrupted (NMI) polyunsaturated fatty acids frequently
observed in marine invertebrates and conifer seeds. As far as the authors know, however, these NMI fatty acid types with mixed
geometry of ethylenic bonds have not been reported previously. 相似文献
11.
Supercritical fluid extraction of lipids from broccoli leaves 总被引:1,自引:0,他引:1
Esther Arnáiz José Bernal María Teresa Martín Cristina García‐Viguera José Luis Bernal Laura Toribio 《European Journal of Lipid Science and Technology》2011,113(4):479-486
The supercritical fluid extraction (SFE) and fractionation of lipids from broccoli leaves is presented in this work. For this purpose the effect of the different variables on the extraction was studied, obtaining the best results at 60°C, 300 bar and 3 mL/min. Two different fractions were obtained: First, the samples were extracted with pure CO2, and afterward the residual material was extracted using CO2 modified with 15% of methanol. The total fatty acid content of the extracts was determined by GC‐MS and compared with those results obtained by Soxhlet extraction with hexane and a chloroform/methanol (2:1) mixture. The SFE extracts presented a higher percentage of unsaturated fatty acids, especially the polyunsaturated 18:3 n ? 3. The methodology was successfully applied to the analysis of the fatty acid composition of the leaves from five different cultivars of broccoli. In all the samples the main fatty acids were α‐linolenic (18:3 n ? 3), linoleic (18:2 n ? 6), and palmitic (16:0). Among the different cultivars analyzed, Naxos variety presented the highest levels in fatty acids, while Parthenon and Viola the lowest. Practical applications: The proposed method allows the fractionation of lipids from broccoli leaves using a small volume of organic solvent and mild conditions. This is advantageous compared to conventional methods where large volumes or organic solvents are used, and the cost and time for the removal of these solvents, along with the possibility of degradation and toxicity, are the major disadvantages. The results obtained contribute to a better compositional characterization and a possible revaluation of this by‐product as a source of biologically active compounds. 相似文献
12.
Under peroxidative conditions (i.e., illumination in the presence of Cu2+ or ap-nitro diphenylether herbicide), the xanthophycean microalga,Bumilleriopsis filiformis, evolves C2 and C5 hydrocarbons besides substantial amounts of propane and propene. Fatty acids were separated as methyl esters by argentation
and reversed-phase thin layer chromatography and the fractions subsequently peroxidized by illuminated and copper-supplementedAnacystis thylakoids. These membranes do not contain polyunsaturated fatty acids and are, therefore, unable to evolve volatile hydrocarbons
by itself. The C2 and C5 hydrocarbons formed by the fractions added match with their content of ω-3 and ω-6 fattyacid species having 2–4 double bonds.
The fractions yielding C3 hydrocarbons contain a fatty acid hitherto unknown forBumilleriopsis, which was isolated and identified as 16∶3ω4. 相似文献
13.
Very long chain polyunsaturated fatty acids such as arachidonic acid (ARA, 20:4n-6), eicosapentaenoic acid (EPA, 20:5n-3),
docosapentaenoic acid (DPA, 22:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are essential components of cell membranes, and
are precursors for a group of hormone-like bioactive compounds (eicosanoids and docosanoids) involved in regulation of various
physiological activities in animals and humans. The biosynthesis of these fatty acids involves an alternating process of fatty
acid desaturation and elongation. The desaturation is catalyzed by a unique class of oxygenases called front-end desaturases
that introduce double bonds between the pre-existing double bond and the carboxyl end of polyunsaturated fatty acids. The
first gene encoding a front-end desaturase was cloned in 1993 from cyanobacteria. Since then, front-end desaturases have been
identified and characterized from a wide range of eukaryotic species including algae, protozoa, fungi, plants and animals
including humans. Unlike front-end desaturases from bacteria, those from eukaryotes are structurally characterized by the
presence of an N-terminal cytochrome b
5-like domain fused to the main desaturation domain. Understanding the structure, function and evolution of front-end desaturases,
as well as their roles in the biosynthesis of very long chain polyunsaturated fatty acids offers the opportunity to engineer
production of these fatty acids in transgenic oilseed plants for nutraceutical markets. 相似文献
14.
Afaf Kamal‐Eldin Nedyalka V. Yanishlieva 《European Journal of Lipid Science and Technology》2002,104(12):825-836
Currently there is great interest in dietary n‐3 fatty acids to promote health. The food industry aims to produce food products enriched in α‐linolenic acid (Ln), eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) to reduce some of the physiological effects of linoleic acid (L), the major polyunsaturated fatty acid in our diet. However, the goal is hampered by the susceptibility of the n‐3 fatty acids to oxidation. As a result the sensory and nutritional quality of such foods deteriorates. Lipid scientists therefore have to find a way to stabilise these fatty acids. Innovative technologies to protect n‐3 polyunsaturates using antioxidants, adequate preparation, refining and packaging of the oil are needed. In this paper we review the inherent stability and the stabilisation of these nutritionally valuable polyunsaturated fatty acids. 相似文献
15.
K. K. Carroll 《Journal of the American Oil Chemists' Society》1965,42(6):516-528
Some characteristics of the fatty acid composition of animal tissue lipids are described and the origins of tissue fatty acids
are discussed briefly. The effect of dietary fat on composition of tissue lipids is discussed. Types of dietary fatty acids
for which experimental work is described include polyunsaturated fatty acids, short-chain fatty acids, fatty acids with chain
length greater than C18,trans unsaturated fatty acids, fatty acids with conjugated double bonds, acetylenic fatty acids, branched-chain fatty acids and
oxygenated fatty acids. The individuality of fatty acids is discussed in relation to their roles as components of tissue lipids. 相似文献
16.
Isomeric fatty acids: Evaluating status and implications for maternal and child health 总被引:2,自引:0,他引:2
Margaret C. Craig-Schmidt 《Lipids》2001,36(9):997-1006
“Isomeric fatty acids” is a term that refers to the trans- and positional isomers formed during hydrogenation of naturally occurring oils. The purposes of this paper are as follows:
(i) to summarize potential exposure of infants to isomeric fatty acids by reviewing estimates of isomeric fatty acids in the
maternal diet, in human milk, and in infant formula/infant foods, and (ii) to evaluate the evidence for adverse effects of
isomeric fatty acids on infant development with respect to growth and essential fatty acid status. Estimates of the intake
of trans-fatty acids vary widely both within and across populations. Current estimates of trans-fatty acids in the North American population are 4–11% of total fatty acids or 3–13 g/(person·d), whereas in Mediterranean
countries in which olive oil is the primary fat and in Far Eastern countries in which little commercially hydrogenated fat
is consumed, per capita consumption of trans-fatty acids is <1–2 g/d. The trans-fatty acid content of human milk reflects the cross-cultural variation in the maternal diet, with trans-fatty acids in human milk samples ranging from 6 to 7% in North America to <0.5% in Hong Kong. Trans-fatty acids are transferred from the maternal diet through the placenta to the developing fetus or through milk to the breast-fed
infant. In some studies, plasma trans-fatty acids are inversely related to birth weight and head circumference. The hypothesis that dietary trans-fatty acids could inhibit biosynthesis of long-chain polyunsaturated fatty acids with 20 and 22 carbon atoms and thus affect
infant development is supported by studies demonstrating an inverse correlation of plasma trans-fatty acids with n−3 and n−6 long-chain polyunsaturated fatty acids in infants. However, no such relationship has been observed
in human milk. A definitive answer concerning a potentially adverse effect of dietary trans-fatty acids on infant development awaits future studies. 相似文献
17.
Roberta Claro da Silva Fabiana Andreia Schaffer De Martini Soares Thaís Gonzaga Fernandes Anna Laura Donadi Castells Kelly Caroline Guimarães da Silva Maria Inês Almeida Gonçalves Chiu Chih Ming Lireny Aparecida Guaraldo Gonçalves Luiz Antonio Gioielli 《Journal of the American Oil Chemists' Society》2011,88(12):1925-1933
Structured lipids (SL), formulated by blends of lard and soybean oil in different ratios, were subjected to continuous enzymatic
interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) in a continuous packed bed reactor. The original and interesterified blends were examined for fatty acid
and triacylglycerol composition, regiospecific distribution, and solid fat content. Blends of lard and soybean oil in the
proportions 80:20 and 70:30 (w/w), respectively, demonstrated a fatty acid composition, and proportions of polyunsaturated/saturated
fatty acids (PUFA/SFA) and monounsaturated/polyunsaturated fatty acids (MUFA/PUFA), that are appropriate for the formulation
of pediatric products. These same blends were suited for this purpose after interesterification because their sn-2 positions were occupied by saturated fatty acids (52.5 and 45.4%, respectively), while unsaturated fatty acids predominantly
occupied sn-1,3 positions, akin to human milk fat. Interesterification caused rearrangement of triacylglycerol species. 相似文献
18.
Uptake and incorporation of long-chain fatty acids were studied in a human colorectal cancer cell line (HT29/219) grown in
culture medium supplemented with either fetal calf serum (FSC) or horse serum (HS). The cells were grown for 120 h with no
change of medium; the two major cellular lipid classes, the phospholipids and the triacylglycerols, were analyzed at regular
time-points. We observed significant changes in the concentration of most fatty acids throughout culture, and differences
in their composition when different sera were used to supplement the medium. Minimal levels of free fatty acids were found
in the cells, indicating a very small “free fatty acid pool”. A major difference between the cells grown in media supplemented
with different sera was the changes observed in concentrations of cellular polyunsaturated fatty acids during growth. In cells
grown with FCS (in which 20∶4n−6 is present), the levels of this acid in the phsopholipid and triacylglycerol fractions declined
rapidly during cell growth, suggesting further metabolism. In cells grown in medium supplemented with HS, 18∶2n−6 was the
major polyunsaturated acid present. There was clear evidence that this acid accumulated in the cellular triacylglycerol and
phospholipid fractions. Furthermore, its concentration did not decline during growth in culture, suggesting minimal conversion
to other polyunsaturated n−6 acids. Our results suggest that fatty acids from additional sources in the medium, for example
triacylglycerols and phospholipids associated with the lipoproteins, are taken up by the cells. There is also indication of
cellular fatty acid synthesis, particularly of monounsaturated and saturated acids during the culture period. HT29/219 cells
were shown to take up and incorporate radioactivity when trace amounts of [1-14C]-labeled arachidonic, linoleic or oleic acids were added to the culture medium. Most (80%) of the label was detected in
cellular phospholipids and triacylglycerols, although the specific activities of these various fatty acids were different
in the two lipid fractions. 相似文献
19.
Bjørnar Myrnes Harald Barstad Ragnar L. Olsen Edel O. Elvevoll 《Journal of the American Oil Chemists' Society》1995,72(11):1339-1344
Marine triglyceride oils (cod liver oil and oils from blubber of harp seal and minke whale) were reacted with glycerol using
lipase as a catalyst at low temperature. A solvent-free batch system with magnetic stirring was used. Solidification of the
reaction mixture occurred, and a mixture of mono-, di-, and triglycerides was obtained in all cases. The recovered glyceride
mixtures were solid at room temperature. The yield of monoglyceride (MG) and the fatty acid profile of the MG fractions were
dependent on oil and the type of lipase used as a catalyst. Of the commercially-available lipases investigated, lipase AK
fromPseudomonas sp. synthesized the highest yield of MG (42–53%) at 5°C. These MG fractions were low in saturated fatty acids (4–11%) and
high in long-chain monounsaturated fatty acids (52–69%). The concentration of n-3 polyunsaturated fatty acids was 12–20%. 相似文献
20.
Manju Bala T. N. Nag Sandeep Kumar Manmohan Vyas Arun Kumar N. S. Bhogal 《Journal of the American Oil Chemists' Society》2011,88(4):559-562
The chemical characteristics of Pongamia pinnata seeds, focussing on proximate composition and the fatty acid profile of its oil, are presented. The proximate composition
of P. pinnata seeds was: 3.8% ash, 9.7% sugar, 7.07% protein, 24% oil, 10.7% free amino acids, and 0.24% free fatty acids. The oil was
extracted from seeds by use of different solvents and the highest yield (29%) was obtained by use of n-hexane. Monounsaturated and polyunsaturated fatty acids accounted for 63.3 and 22.9%, respectively, of the seed oil. Oleic
acid was the major fatty acid but a substantial amount of erucic acid was also detected; this was not reported in previous
studies. The level of erucic acid and the presence of toxic flavonoids, for example karanjin, pongapin, and pongaglabrin,
render the oil inedible according to WHO recommendations. However, low levels of saturated and polyunsaturated fatty acids
with desirable cetane number and iodine value suggest potential for application as a biodiesel fuel. 相似文献