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1.
Karin Weber E. Schulte H.-P. Thier 《European Journal of Lipid Science and Technology》1988,90(9):341-344
HPLC Separation of Triglycerides in Bovine and Human Milk and GLC Analysis of the Isolated Fractions Reversed-phase HPLC using acetonitrile-propionitrile mixtures and a very simple temperature programming device (temperature rising from 10–15°C up to 60°C) yielded optimum separation of the triglycerides in bovine milk (winter and summer) and mature human milk. The components in the isolated fractions were analysed by GLC for triglycerides and fatty acid methyl esters. 相似文献
2.
L. Brühl E. Schulte H.-P. Thier 《European Journal of Lipid Science and Technology》1994,96(4):147-154
Composition and Structures of Triglycerides of Human Milk and Some Base Components for Infant Milk Formulas Following HPLC separation of human milk triglycerides with a silver-loaded ion exchange and an RP-18-phase column, the 50 substantial fractions obtained were characterized by gas chromatography of triglycerides and fatty acid methyl esters as well as by the analysis of intramolecular distribution on a reduced scale using ethyl magnesium bromide. Exploitation of all data available resulted in the detailed structures of 106 triglycerides, representing 81 g/100 g human milk fat. A substitute for producing infant milk formulas should be adapted to the composition and fatty acid distribution of those 14 substantial triglycerides which are present in human milk fat with more than 1 g/100 g, amounting to a total of 42 g/100 g. Among several fats and oils analyzed, only lard and a recent product were found to contain palmitic acid also predominantly in the 2-position. Therefore, other base components would require a directed fractionation and/or interesterification to be best adapted to human milk fat. 相似文献
3.
Karin Weber E. Schulte H. P. Thier 《European Journal of Lipid Science and Technology》1989,91(3):113-115
Comparison between the triglyceride Patterns of Human Milk and Infant Milk Formulae Human milk contains less triglycerides with saturated fatty acids than the three infant milk formulae analysed but has a higher content of triglycerides with two unsaturated fatty acids. The patterns of the major triglycerides are compared. In human milk, palmitic acid is preferably located in position 2 favourable to digestability, whereas in the infant milk formulae it is mostly distributed over positions 1 and 3. 相似文献
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The Composition of Lipids of Animal Organ and Depot Fats in Relation to Feed II: Gas-chromatographic Analysis of Fatty Acids of Calves and Cattle Fats In the milk as well as in the fats of calves and cattle 81 fatty acids were found. The composition of fatty acids of the depot and organ fats of cattle — in winter with stall-feeding and in summer with pasture-feeding — were compared with the winter and summer milk fats. The differences between the fats from the same parts of calves and cattle are discussed. 相似文献
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A. Seher 《European Journal of Lipid Science and Technology》1971,73(8):481-486
Determination of Melting and Solidification Temperatures of Fats Considerable fluctuations in results are observed when solidification temperatures, and, especially melting temperatures are determined by customary methods. In an apparatus developed by Walisch and Eberle, the sample is heated in an oven under linear increase in temperature, during which the temperature within the sample is measured. In pure glycerides and various fats, the resulting temperature-time curve enables detection of the polymorphic crystalline transformations and determination of the entire temperature region at which melting occurs. Reproducibility of the results was very good. In parallel studies using NMR-spectrometry, the amount of liquid part as a function of temperature was measured. The results agreed with melting diagrams. The cooling curve served for determining solidification point in a most reproducible manner and for detecting polymorphic transformations. 相似文献
8.
In the reaction of AsCl2F3 with graphite, intercalation compounds of stage n = 3 are produced with an identity period of Ic = 1.49 nm. The stoichiometry of the compounds varies in consequence of the dissociation and dismutation reactions of AsCl2F3. The exfoliation of the crystals and the release of chlorine have been observed during heat treatment. The maximum thermal deintercalation is between 350 and 440°C. Only chlorine and arsenic trihalides, no pentahalides, have been detected by mass spectrometric analysis of the pyrolysis gases. Thermogravimetric investigations of SbClmF5-m graphite intercalation compounds as well as mass spectrometric analyses of the pyrolysis gases show that in the deintercalation of the original intercalated pentahalides, their thermal dissociation as well as dismutation by halogen exchange overlap in the course of thermal decomposition. The conversion of stage 1 SbCl4F graphite to stage 2 and the formation of dilute stage 2 SbCl5 graphite as well as SbCl4F graphite take place at 80–110°C. A high concentration of the pentahalides SbCl5 and SbCl4F respectively and a low concentration of trihalides have been found by mass spectrometry in the gas phase at 80–110°C. This low-temperature deintercalation is assumed to be a complete or partial emptying of galleries without a structural modification of the graphite layers. The structural conversions of stages n > 2 into stages n + 1 at higher temperatures of about 200 and 300°C are explained by a Daumas-Hérold domain model. Powdered natural graphite and synthetic graphite exhibit a preferred deintercalation of halides at 80–110°C. This may be explained by a higher density of diffusion paths and a lower ratio of crystallite sizes to domain sizes with respect to graphite flakes. The thermal dissociation of the pentahalides beginning at 190–200°C overlaps with the conversion of stage 2 to stage 3. At the same time chlorine is explosively released, leading to the exfoliation of the graphite flakes. The conversions of higher stages open intercalate islands in the crystal bulk and, consequently, the concentrations of the pentahalides and their dissociation products in the gas phase increase. The conversion of stage 3 to stage 4 occurs in the temperature range of 300–350°C; stages n > 4 degrade between 400 and 430°C. SbCl2F3 graphite as well as AsCl2F3 graphite evolves only the dissociation and dismutation products of the pentahalides. With an increase of temperature, the relative concentrations of SbF3 and AsF3 increase with respect to those of the Cl-containing trihalides; this is a consequence of dismutation with halogen exchange. The formation of polymeric neutral or anionic Sb halide species with fluorine bridges is presumably the reason for the dismutation reactions. 相似文献
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Ulla Brimberg 《European Journal of Lipid Science and Technology》1985,87(8):295-301
The Kinetics of Melting and Crystallization of Cocoa Butter Melting is kinetically the reverse of crystallization. It was shown in a previous publication that the kinetics of fat crystallization is the same as that of precipitation from colloids. It is shown in the present paper that the kinetics of melting of solid fat is the same as that of the dispersion of gels. The kinetics of the melting of cocoa butter was investigated by linearization of experimental data from the literature. The linearization shows that the melting is accompanied by crystal transformations, and that the various crystal forms melt in succession. 相似文献
11.
K. Strnský M. Streibl K. Ubik J. Kahautov L. Novotný 《European Journal of Lipid Science and Technology》1981,83(9):347-354
The Hydrocarbon Composition of Camomile (Matricaria chamomilla L.) The group separation of camomile (Matricaria chamomilla L.) extracts obtained by petroleum ether is described, By column chromatography hydrocarbons, esters, triglycerides, acetylene compounds, free fatty acids, free fatty alcohols and hydroxyesters were separated in n-alkanes, branched alkanes, several types of monoalkenes, terpenoic hydrocarbons. Single components were identified by means of GLC, GLC-MS, IR-and mas-spectrometry. 相似文献
12.
K. D. Haase A. J. Heynen N. L. M. Laane 《European Journal of Lipid Science and Technology》1989,91(9):350-353
Composition and Application of Isostearic Acid The clay catalysed oligomerisation of unsaturated fatty acids yields C36 dimer fatty acids, C54 trimer fatty acids and C18 monomer fatty acids. Monomer fatty acids, which consists mainly of straight, branched, saturated and unsaturated fatty acids, can be distilled from the higher molecular weight products and after hydrogenation separated into solid stearic acid are mono- and polybranched C18 fatty acids whose branching points are mainly concentrated in the center of the molecule. Depending on the nature of the used raw materials and the degree of refinery, straight chain fatty acids, cyclic fatty acids, γ-lactones, unsaponifiable and even rosin acids are found as impurities. The low cloudpoint, comparable with oleic acid, as well as the excellent temperature- and oxidation stability gives isostearic acid and their derivatives excellent opportunities in applications as cosmetics, lubricants and plastics. 相似文献
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K. Aitzetmüller H. Wessels G. Werner 《European Journal of Lipid Science and Technology》1988,90(11):442-447
Analytical Characterisation of Palm Oil Fractions by HPLC of Triglycerides The increasing importance of palm oils and palm oil fractions in international trade makes it necessary to develop analytical criteria for the characterisation of these products. One problem is the correct identification of palm oleins, which are often difficult to distinguish from palm oils. These products frequently exhibit similar fatty acid by GLC and similar iodine values. The correct identification of palm stearins by GLC is comparatively more easy. Palm oleins and palm oils can be characterized by HPLC using conditions that permit not only the separation of triolein from less unsaturated triglycerides of the same carbon number, but also, at the same time, a separation of tripalmitin from triglycerides containing oleic acid. By establishing the peak area ratios for a number of selected triglycerides a clear differentiation between palm oils and palm oleins, as well as various other palm oil fractions and their mixtures is obtained. 相似文献
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The Decisive Cooperation of Metal and Oxygen Ions of Nickel Oxide During the Oxidation of o-Xylene As can be concluded from the experimental results at 450°C in the reaction mixtures consisting of N2 O2-o-Xylene, both nickel oxide pure and doped with Li2O or In2O3 is unsuited as catalyst for the oxidation of o-xylene to phthalic anhydride. In contrast to NiO which ionosorbs both oxygen and o-xylene, NiO Li2O, a strong ionosorbent for o-xylene, prevents the ionosorption of oxygen because of the large concentration of holes. Since gaseous oxygen does not react with ionosorbed o-xylene but a reduction of nickel oxide to metallic nickel has been observed in spite of the fact of enough oxygen in the gas phase it can be assumed that o-xylene is forced to remove oxygen ions from the NiO lattice under generation of oxygen-ion vacanxies and nickel atoms. The predominant portions of the reaction products are H2O and CO2. With undoped nickel oxide and NiO In2O3 which were not reduced under the same experimental conditions, the reaction products had roughly the same composition. The reduction of NiO Li2O however will be prevented in a gas mixture with a high oxygen pressure which oxidizes the formed nickel atoms on the surface of NiO Li2O to nickel oxide making possible the entrance of oxygen from the gas phase and, therefore, the oxidation of o-xylene. A turbulent motion of a 2-component catalyst powder from NiO-1mole% Li2O covered with ionosorbed o-xylene and ZnO-1mole% In2O3 covered with ionosorbed oxygen in the same gas mixture resulted in the same reaction products as in the presence of sole NiO Li2O under simultaneous reduction of nickel oxide. From that we can conclude that the oxidation of o-xylene by oxygen ions of NiO occurs more easily than the reaction with ionosorbed oxygen on ZnO In2O3 which obviously seems to be bounded too strongly. This result is also confirmed by the prevention of the oxidation of gaseous o-xylene in the presence of only ZnO In2O3. Finally, the operation of the carrier catalyst V2O5/TiO2 which is employed for the oxidation of o-xylene to phthalic anhydride will be prevented to a large extent in simultaneous presence of nickel oxide either pure or doped with Li2O and In2O3 in roughly the same amount. This result can be mentioned as a proof for the interaction of a 2-component catalyst the mechanism of which is at present not satisfactorily understood. 相似文献
15.
Composition of the Sterol Fraction of Refined Vegetable Oils The changes in the sitosterol and its derivatives under the influence of bleaching earth were studied. Further, the composition of the sterol fraction of rapeseed oil in different stages of refining was examined. 相似文献
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H. P. Nissen G. Ortel K. Macke H. W. Kreysel 《European Journal of Lipid Science and Technology》1983,85(1):39-42
The Skin-Surface Lipids in Psoriasis vulgaris (Ps) - Cholesterol Esters, Wax Esters, Triglycerides and Fatty Alcohols The composition of waxes and cholesterol esters, triglycerides and alcohols of hair lipids from subjects with psoriasis vulgaris and control group was determined by gas liquid chromatography. The amount of palmitoleic acid was lower in the lipid group of the waxes and cholesterol esters in psoriasis vulgaris. Triglycerides show two different changes in the fatty acid pattern by psoriasis: 1) the composition of shorter chain fatty acids was distinct lower but 2) patients with a heavy psoriasis show an increase of the shorter chain fatty acids especially lauric acid and a decrease of the longer chain fatty acids. The analysis of the alcohols indicates that psoriatic patients possess a higher content of alcohols with 12,13 and 14 carbonatoms than normal subjects. 相似文献
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M. Streibl J. Jirouov K. Strnský 《European Journal of Lipid Science and Technology》1971,73(5):301-305
Natural Waxes XVII: Composition of Sperm Oil Two samples of sperm oil were separated by preparative gas chromatography into five fractions corresponding to the major peaks. Exact composition of the component acid and alcohol could be determined by micro-interesterification of the above fractions. Cetyl ester of lauric acid is the main component (> 80%) in the group of isomeric C28-esters; the major components of C30-esters and C32-esters are cetyl myristate (~ 80%) and cetyl palmitate (~ 75%) respectively. Stearyl palmitate (55%) dominates in the group of C34-esters and stearyl stearate (~ 60%) is the major component in the group of C36-esters. Experiments were also carried out to determine compositions of isomeric esters in the five gas chromatographic fractions from their mass spectra. 相似文献
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O-Methylation of tert-Alkylpyrocatecholes. Analytical Method for Determination of the Content of Product Mixtures and Way for Preparation of 4-tert-Alkylveratroles The O-methylation of tert-alkylpyrocatecholes with dimethylsulfate leads to a mixture of substituted guaiacoles 6/7 , 9/10 and veratroles 5 , 6 which are separated by gas/liquied-chromatography for analytical purposes. It is also possible to prepare 4-tert-alkylsubstituted veratroles 5 with good yields in this way. On the other hand, the alkylation of veratrole was only successful with lower tert-alkanols or alkenes. Long-chained tert-alkanols fail in this reaction. The analytical and spectroscopical data of some new 4-tert-alkylveratroles 5a—g are given. 相似文献
19.
The process of incorporating 6-caprolactam and 8-capryllactam into polymer chains was studied during the hydrolytic, cationic, and anionic copolymerization in the case of equimolar ratio of the above mentioned monomers. At the beginning of the hydrolytic copolymerization at temperatures between 200 and 260°C, 6-caprolactam was more rapidly incorporated into the chains. Decreasing temperature led to a decrease in the total rate of polymerization with increasing difference between rates of incorporating the two components. Contrary to this, at the initial stage of the cationic copolymerization, the incorporation of 8-capryllactam was faster by orders of magnitude than that of 6-caprolactam, the changes of the copolymer composition being independent of temperature. Under the conditions of interest, in the course of the anionic copolymerization the two monomers were characterized with the same rates of incorporation into the polymer chains. Different melting points of products separated at various stages of the copolymerization process corresponded to the above mentioned differences in rates of incorporating individual monomers into polymer chains when different reaction mechanisms were employed. 相似文献
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