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Electrochemical impedance spectroscopy was used for the study of two-component lipid membranes. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were to be investigated, because of their presence in biological membranes. Capacitance values of pure components are 0.62 and 0.32 μF cm−2, respectively. The 1:1 complex was formed during formation of the PC-PE lipid membrane. Formation of the complex can explain the deviation from the additivity rule. This equilibrium was described by mathematical equations and was further verified experimentally. Adequate equations let us calculate such parameters as: capacitance of the complex molecule, area occupied by the complex molecule as well as the stability constant of the complex. 相似文献
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《Food Control》2015
The effects of deep-fat frying performed using different culinary fats (extra virgin olive oil, conventional sunflower oil and high-oleic sunflower oil) and different frying temperatures (160 and 180 °C) on the composition of the preponderant fish phospholipid classes, phosphatidylethanolamine (PE) and phosphatidylcholine (PC), were investigated on Sardina pilchardus. The total fish lipid fraction was injected into the HPLC system coupled on line with a second order mass spectrometer (MS–MS) by means of electronebulization interface (ESI), without a prior clean-up of the phospholipid fraction.The deep-fat frying process caused significant changes on PE and PC molecular species composition of the fish fillet.In all cases, the deep-fat frying process caused a significant (P < 0.05) increase in the relative proportions of the PE and PC species constituted by the combination of palmitic and docosahexaenoic acids. At the same time, a depletion of the percentage of the PE and PC species formed by two docosahexaenoic acid residues in fried fillets was registered. Anyway, this depletion was statistically significant for PC, but not for PE.Both PE and PC compositions were not influenced by the frying temperature, whereas the nature of the culinary fat had an effect on the PC composition. Particularly, the frying tests with conventional sunflower oil produced a statistically significant increase of PC species containing saturated/polyunsaturated fatty acids and a significant decrease of PC species formed by the combination of two polyunsaturated fatty acids. 相似文献
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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
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Purification of Soybean Phosphatidylcholine Using D113-III Ion Exchange Macroporous Resin Packed Column Chromatography 总被引:1,自引:0,他引:1
Yuanfa Liu Liang Shan Xingguo Wang 《Journal of the American Oil Chemists' Society》2009,86(2):183-188
Ten ion-exchange resins were compared for their abilities to separate soybean phosphatidylcholine (PC). D113-III resin was
selected for PC purification among ten resins tested. The optimum PC adsorption conditions were: concentration of PC solution,
3 mg/mL; pH of PC solution, 7.5; and adsorption flow rate, 1 mL/min. The optimum PC desorption conditions were: eluent, 95%
ethanol aqueous solution; and elution flow rate, 1 mL/min. Under these conditions, the PC content in the product and the amount
of product were 94 and 80% (wt.%), respectively, and the D113-III resin was able to be used at least six times for purifying
PC. The adsorption and desorption characteristics were also studied. 相似文献
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Han Xiao Deli Hong Tongyang Zhu Shanli Liu Genxi Li 《Journal of Applied Electrochemistry》2009,39(8):1163-1167
The ion-channel formation of outer membrane protein F (OmpF) can be achieved in phosphatidylcholine bilayer membrane modified
on a pyrolytic graphite electrode, which makes it possible to sense the porin functionality conveniently with an electrochemical
technique through the change in the redox peaks currents of an electroactive marker. The effect of ionic strength, pH on the
ion permeability of OmpF and the effect of the protein concentration on the ion-channel formation have been thus examined.
This study may provide a simple and rapid way to probe other similar biological processes within natural cellular membranes. 相似文献
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以磷脂酰胆碱(PC)富集物和二十二碳六烯酸(DHA)浓缩液为底物,正己烷为反应介质,在固定化磷脂酶A1(PLA1)的催化作用下,制备DHA型磷脂(PL-DHA)。研究了底物摩尔比、加酶量、溶剂用量、反应温度、水活度、反应时间对PL-DHA制备的影响。通过条件优化,确定最佳条件为:DHA浓缩液和PC的摩尔比为4∶1,加酶量为2种底物总质量的20%,溶剂用量为4 m L,反应温度为40℃,反应时间为2 h。经气相色谱定量分析,得到的磷脂中DHA的含量为17.7 mg/g PL,并用棒状薄层色谱火焰离子检测器(TLC-FID)分析了PC含量随反应的变化。 相似文献
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Julie Le Grandois Eric Marchioni Saïd Ennahar Francesca Giuffrida Françoise Bindler 《Food chemistry》2010
Heat-induced oxidative modifications of two phosphatidylcholine molecular species as potential functional food components were evaluated. 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) and 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (SLPC) were chosen as models. The optimal temperature for hydroperoxide formation was determined by MS for each standard: 125 °C for SLPC and 150 °C for SOPC. Oxidation was performed at these temperatures and degradation products were identified using LC–ESI-MS combined to an acid treatment. Kinetics of formation of oxidation products from SOPC and SLPC were monitored over 120 min and curves were drawn for each identified structure. Results showed that native phospholipids rapidly decreased with heat and that oxidation products showed functions, such as hydroxyl, oxo or epoxy groups. Kinetics pointed out that some of these quite stable oxidation products are likely to be found in sizable amounts in processed foods containing phospholipids. 相似文献
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Didier Dupont Giuseppina Mandalari Daniel Molle Julien Jardin Joëlle Léonil Richard M. Faulks Martin S. J. Wickham E. N. Clare Mills Alan R. Mackie 《Molecular nutrition & food research》2010,54(6):767-780
IgE‐mediated allergy to milk and egg is widespread in industrialised countries and mainly affects infants and young children. It may be connected to an incomplete digestion of dietary proteins causing an inappropriate immune response in the gut. In order to study this, a biochemical model of infant gastroduodenal digestion has been developed, which has reduced levels of protease (eightfold for pepsin and tenfold for trypsin and chymotrypsin), phosphatidylcholine and bile salts, compared with the adult model. This model has been used to study the behaviour of three characterised food‐relevant proteins (bovine β‐lactoglobulin (β‐Lg), β‐casein (β‐CN) and hen's egg ovalbumin), all of which are relevant cows' milk and hens' egg allergens. Digestion products were characterised using electrophoresis, immunochemical techniques and MS. These showed that ovalbumin and β‐CN were digested more slowly using the infant model compared with the adult conditions. Resistant fragments of β‐CN were found in the infant model, which correspond to previously identified IgE epitopes. Surprisingly, β‐Lg was more extensively degraded in the infant model compared with the adult one. This difference was attributed to the tenfold reduction in phosphatidylcholine concentration in the infant model limiting the protective effect of this phospholipid on β‐Lg digestion. 相似文献