共查询到20条相似文献,搜索用时 78 毫秒
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Jürgen Schiller Rosemarie Süß Marijana Petkovi Gran Hanke Alexander Vogel Klaus Arnold 《European Journal of Lipid Science and Technology》2002,104(8):496-505
It is well‐known that triacylglycerols in vegetable oils undergo slow oxidative modifications upon storage particularly at elevated temperatures. This has been shown primarily for oils with unsaturated fatty acid residues that are most sensitive towards oxidation. Saturated oils, however, were by far less investigated. In the present study saturated oils (coconut oil) as well as isolated triacylglycerols were exposed to defined thermal stressing and the resulting products were investigated in dependence on temperature and the heating period. Matrix‐assisted laser desorption and ionization spectrometry, 13C and 31P nuclear magnetic resonance spectroscopy and infrared spectroscopy were used for the characterization of the native as well as the thermally stressed oil samples. These methods were used since they provide both, fast and reliable information on oil composition and can be performed faster than other more established methods. We found that the degradation mechanism of saturated fatty acids is completely different from unsaturated fatty acids. Whereas unsaturated oils are primarily depleted under the cleavage of the double bonds, saturated oils undergo a conversion of one methylene group into a carbonyl group. This was independently demonstrated by all applied methods for the triacylglycerols as well as for the free fatty acids derived after saponification. 相似文献
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Ran Liu Yuan Peng Xiaobo Li Yi Wang Enchun Pan Wei Guo Yuepu Pu Lihong Yin 《International journal of molecular sciences》2013,14(5):8899-8911
Epidemiological studies indicated that esophageal squamous-cell carcinoma (ESCC) is still one of the most common causes of cancer incidence in the world. Searching for valuable markers including circulating endogenous metabolites associated with the risk of esophageal cancer, is extremely important A comparative metabolomics study was performed by using ultraperformance liquid chromatography-electrospray ionization-accurate mass time-of-flight mass spectrometry to analyze 53 pairs of plasma samples from ESCC patients and healthy controls recruited in Huaian, China. The result identified a metabolomic profiling of plasma including 25 upregulated metabolites and five downregulated metabolites, for early diagnosis of ESCC. With a database-based verification protocol, 11 molecules were identified, and six upregulated molecules of interest in ESCC were found to belong to phospholipids as follows: phosphatidylserine, phosphatidic acid, phosphatidyl choline, phosphatidylinositol, phosphatidyl ethanolamine, and sphinganine 1-phosphate. Clinical estimation of metabolic biomarkers through hierarchical cluster analysis in plasma samples from 17 ESCC patients and 29 healthy volunteers indicated that the present metabolite profile could distinguish ESCC patients from healthy individuals. The cluster of aberrant expression of these metabolites in ESCC indicates the critical role of phospholipid metabolism in the oncogenesis of ESCC and suggests its potential ability to assess the risk of ESCC development in addition to currently used risk factors. 相似文献
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In this study, Chinese gallotannins were characterized by MALDI‐TOF MS, and effects of cationization reagents on the quality of spectra were investigated. The trideca‐ and tetradeca‐galloyl glucoses were observed in Chinese gallotannins, which could not be detected in earlier studies. When Cs+ was used as the cationization reagent, Chinese gallotannins gave a relatively simple MALDI‐TOF spectrum, three series of quasimolecular ions [M + Cs]+, [M + 2Cs–H]+, and [M + 3Cs–2H]+ and a series of metastable ion peaks with minimum abundance were detected. Selection of Na+ as the cationization reagent, additional three series of ion peaks including two patterns from the fragmentation and complex 2M adducts [2M + Na]+ can be distinguished. In the case of no deionization or addition of cationization reagent to the analyte/matrix, naturally abundant Na+ and K+ as the cationization reagent, [M + Na]+ and [M + K]+ molecular ions both appeared in the complicated spectrum. Therefore, we conclude that cationization reagents affect the MALDI‐TOF MS spectrum of Chinese gallotannins significantly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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The polymer additives are key factor materials in the Cu electroplating process, essential for controlled acceleration and inhibition of Cu deposition. In this study, the degradation behavior of a polymer additive—poly(ethylene glycol) (PEG)—during the Cu electroplating was investigated by MALDI‐TOF MS technique. The PEG was completely degraded after 4 h at a constant electric current density of 13 mA/cm2, whereas it showed no degradation without an electric field even at a very low pH (pH < 1). The pathways and energetics of PEG degradation by electrolysis in aqueous chloride medium was investigated using density functional theory calculations at the same time. It demonstrated how facile the decomposition of PEG internal radical is, which is generated via the hydrogen abstraction from PEG by hydroxyl radical formed at the anode in aqueous chloride medium under an electric field. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Masahiro Hasegawa Hideki Hakamata Io Matsunaga Fumiyo Kusu 《European Journal of Lipid Science and Technology》2011,113(4):423-429
A simple method for the detection of oxysterols in oxidatively modified LDL (Ox‐LDL) has been developed using MALDI‐TOF MS. To identify the ion peaks of oxysterols, seven major oxysterols in Ox‐LDL (7α‐hydroxycholesterol, 7β‐hydroxycholesterol, 7‐ketocholesterol, 5α,6α‐epoxycholesterol, 5β,6β‐epoxycholesterol, 25‐hydroxychokesterol, (25R)‐26‐hydroxycholesterol), and cholesta‐3,5‐dien‐7‐one were analyzed by MALDI‐TOF MS. Among these oxysterols, 7‐ketocholesterol, a very abundant oxysterol in Ox‐LDL, was found to show a characteristic peak of [M + H]+ at m/z 401. Cholesta‐3,5‐dien‐7‐one, which is known as a degradation product of 7‐ketocholesterol upon saponification of Ox‐LDL, gave a major peak of [M + H]+ at m/z 383. In contrast, other oxysterols showed similar peak patterns at m/z 367 and 385. These results were applied to the analysis of Ox‐LDL by MALDI‐TOF MS after saponification and hexane‐extraction, detecting ion peaks at m/z 367, 383, 385, and 401. This MALDI‐TOF MS method has a potential as a simple tool to show the presence of oxysterols in Ox‐LDL without derivatization and chromatographic separation. 相似文献
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Sabine Krist Gerald Stuebiger Stefanie Bail Heidrun Unterweger 《European Journal of Lipid Science and Technology》2008,110(2):127-140
Some typical original Indian edible and non‐edible fatty plant oils were subject of our investigations. Fundamental research was done on analyzing volatile compounds using HS‐SPME‐GC‐MS. In addition, a sensorial evaluation was applied to receive data on the smell of the samples. Furthermore, the typical and prevailing triacylglycerols (TAG) were investigated by MALDI‐TOF‐MS. Mass spectra reflect the TAG profiles of the whole oil samples based on the detection of [M+Na]+ ions. Oil samples exhibit quite unique TAG profiles, which are suitable for rapid characterization of the original plant oils. The fatty acid composition of the corresponding TAG structures was calculated using lipid analysis software based on the known fatty acid composition. Relative quantification of TAG components was in good agreement with the literature, in case appropriate data are available so far. 相似文献
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Stefanie Bail Gerald Stuebiger Heidrun Unterweger Gerhard Buchbauer Sabine Krist 《European Journal of Lipid Science and Technology》2009,111(2):170-182
Several nut oil varieties mainly used as culinary and overall healthy food ingredients were subject of the present study. Headspace solid‐phase microextraction combined with gas chromatography‐mass spectrometry was employed in order to determine the qualitative composition of volatile compounds. Furthermore, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used in order to assess the profiles and relative composition of the prevalent triacylglycerols (TAG) within the oils. The headspace of the majority of oil samples was dominated by high contents of acetic acid (up to 42%) and hexanal (up to 32%). As nut oils are typically gained by cold‐pressing from previously roasted nuts, characteristic pyrazine derivatives as well as degradation products of long‐chain fatty acids were detected. TAG analysis of these oils revealed a quite homogeneous composition dominated by components of the C52 and C54 group composed mainly of oleic (18:1), linoleic (18:2), stearic (18:0) and palmitic (16:0) acid residues representing together between 65 and 95% of the investigated nut oils. The TAG profiles showed characteristic patterns which can be used as ‘fingerprints’ of the genuine oils. Nut oils exhibiting quite similar fatty acid composition (e.g. hazelnut, pistachio and beech oil) could be clearly discriminated based on TAG showing significant differences between the oils. 相似文献
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A series of macrocyclic(arylene sulfide) oligomers were synthesized by reaction of 4,4′‐oxybis(benzenethiol) with a number of difluoro compounds in dimethylformamide (DMF) in the presence of anhydrous K2CO3 under high dilution conditions. The difluoro compound can be 4,4′‐difluorobenzophenone, bis(4‐fluorophenyl)sulfone or 1,3‐bis(4‐fluorobenzoyl)benzene. Detailed structural characterization of these oligomers by matrix‐assisted laser desorption and ionization‐time of flight‐mass spectroscopy (MALDI‐TOF‐MS) demonstrated their cyclic nature. The MALDI‐TOF‐MS technique has proved to be a powerful tool to analyze these cyclics. These cyclic oligomers are amorphous and highly soluble in DMF and N,N′‐dimethyl acetamide. Moreover, these cyclic(arylene sulfide) oligomers readily underwent ring‐opening polymerization in the melt at 285 °C in the presence of 2,2′‐dibenzothiazole disulfide, affording linear, high molecular weigh poly(aromatic sulfide)s. These polymers are insoluble in most common solvents. Copyright © 2004 Society of Chemical Industry 相似文献
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The Phospholipid Composition of Kangaroo Spermatozoa Verified by Mass Spectrometric Lipid Analysis 下载免费PDF全文
Cryopreservation of kangaroo sperm has not been successful so far, and yet there is no promising cryopreservation protocol for these cells available. However, conservation of gametes is extremely important, particularly in the context of preserving endangered species. As spermatozoa are comprised of different membrane systems, the composition of these membranes might account for difficulties in cryopreservation. Lipids, as the main components, affect the physical properties of biological membranes and play a major role in sperm maturation. Therefore, knowledge of the lipid composition is crucial for any further step toward the preservation of the species. We used MALDI‐TOF, ESI‐IT, tandem mass spectrometry, and thin layer chromatography to investigate the lipid composition of epididymal spermatozoa of four different kangaroo species. Spectra of these species were very similar with respect to the identified lipid species. Tremendous changes in the lipid composition during the transit of sperm from caput to cauda epididymis could be seen, specifically an increase in poly‐unsaturated fatty acids, ether lipids, and plasmalogens, as well as a reduction in mono‐ and di‐unsaturated fatty acids. Additionally, phosphatidylcholines containing docosatrienoic acid (22:3), a heretofore unknown fatty acid for sperm membranes, showed the highest abundance in kangaroo sperm. 相似文献
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Rosaria Cozzolino Beatrice De Giulio 《European Journal of Lipid Science and Technology》2011,113(2):160-167
Triacylglycerols (TAG) are the most important group of compounds present in vegetable oils. These biomolecules, determining the physical, chemical and nutritional properties of the oils, are considered to be good fingerprints for quality and authenticity control. Therefore, TAGs characterization is a very important task in edible oil field, which has been undertaken by different analytical methods. The analysis of vegetable oils is still dominated by classic determinations, which are however laborious and time‐consuming and cannot be used routinely. More recently, advances in MS instrumentations coupled with online separation techniques and data processing have contributed to great expansion of MS in oil study, allowing the development of innovative analytical approaches that exhibit higher sensitivity, accuracy and rapidity in vegetable oils investigations. In the present contribution, a review of the most relevant applications of novel mass spectrometric techniques, such as ESI and MALDI, both alone and hyphenated with HPLC, used for analysis of the complex TAGs mixture of edible oils is illustrated. 相似文献
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Influence of deodorization temperature on formation of tocopherol esters and fatty acids polymers in vegetable oil 下载免费PDF全文
František Kreps Jan Kyselka Zuzana Burčová Štefan Schmidt Aleš Rajchl Vladimír Filip Aleš Ház Michal Jablonský Alexandra Sládková Igor Šurina 《European Journal of Lipid Science and Technology》2017,119(3)
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Daniela Antunes Montani Thaís Regiani Amanda Begati Victorino Jacqueline Camillo Eduardo Jorge Pilau Fábio Cesar Gozzo Daniel Suslik Zylbersztejn Christina Ramires Ferreira Edson Guimarães Lo Turco 《Lipids》2014,49(9):957-962
This research aimed to study the changes in lipid composition in cumulus cells using hyaluronidase according to the intracytoplasmic sperm injection protocol commonly used in human reproduction clinics. The lipid extraction was performed by the Blight‐Dyer protocol and the lipid profiles were obtained by MALDI‐TOF MS in positive and negative modes. The mass spectra data were processed with MassLynx and the statistical analysis was performed using MetaboAnalyst 2.0. Fifteen ions were selected for each mode as potential markers for differences between the groups. These ions were identified in the human metabolome database as phosphatidylserine with and without treatment, phosphatidylethanolamine in the after treatment group and phosphatidylinositol in the before treatment group, which are lipids that may be involved in cell apoptosis and signaling. We concluded that MALDI‐TOF MS coupled with multivariate analysis can be utilized as a strategy to obtain and study the lipid profiles of cumulus cells and as a tool to study the metabolic state of cumulus cells. 相似文献
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Freeze‐dried leaf, stem bark, and root bark powders of Aegiceras corniculatum were extracted with three different types of polar solvents: methanol, ethyl acetate, and water. The methanol extracts had the highest concentrations in total phenolics and extractable condensed tannins, followed by water and ethyl acetate extracts. Analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) suggested that condensed tannins from leaf, stem bark, and root bark contained prodelphinidins and procyanidins, with the predominance of prodelphinidins and high level of galloylation. Acid‐catalyzed degradation in the presence of benzyl mercaptan indicated that gallocatechin, epigallocatechin, epigallocatechin‐3‐O‐gallate, and epicatechin‐3‐O‐gallate occurred as the terminal units and (epi)gallocatechin, (epi)gallocatechin‐3‐O‐gallate, (epi)catechin, and (epi)catechin‐3‐O‐gallate occurred as the extension units. The mean degrees of polymerization (mDP) of condensed tannins from leaf, stem bark, and root bark were 13.5, 7.4, and 12.3, respectively. The condensed tannins from leaf and stem bark exhibited a higher DPPH radical scavenging activity and ferric reducing/antioxidant power compared to that of synthetic antioxidant butylated hydroxyanisole (BHA). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Ana-Marija Jergović Željka Peršurić Lara Saftić Sandra Kraljević Pavelić 《Journal of the American Oil Chemists' Society》2017,94(6):749-757
Adulteration of extra virgin olive oil (EVOO) by addition of other vegetable oils or lower-grade olive oils is a common problem of the oil market worldwide. Therefore, we developed a fast protocol for detection of EVOO adulteration by mass spectrometry fingerprinting of triacylglycerol (TAG) profiles based on MALDI-TOF/MS. For that purpose, EVOO TAG profiles were compared with those of edible sunflower oil and olive oil composed of refined olive oil and virgin olive oils. Adulteration of EVOO was simulated by addition of sunflower and mixture of refined olive oil and virgin olive oils at 1, 10 and 20% w/w. Results of mass spectrometry TAG profiling were compared with routinely assessed K values for identification of adulteration. MALDI-TOF/MS technology coupled with statistical analysis was proven as useful for detection of adulteration in EVOO at a rate down to 1%. In contrast, standard spectrophotometric methods failed to identify minor adulterations. In addition, the ability of MALDI-TOF/MS in detection of adulteration was tested on EVOO samples from different geographical regions. Results demonstrated that MALDI-TOF/MS technology coupled with statistical analysis is able to distinguish adulterated oils from other EVOO. 相似文献
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Mono‐Estolide Synthesis from trans‐8‐Hydroxy‐Fatty Acids by Lipases in Solvent‐Free Media and Their Physical Properties 下载免费PDF全文
Ignacio Martin‐Arjol Terry A. Isbell Angels Manresa 《Journal of the American Oil Chemists' Society》2015,92(8):1125-1141
Pseudomonas aeruginosa 42A2 is known to produce two hydroxy‐fatty acids, 10(S)‐hydroxy‐8(E)‐octadecenoic and 7,10(S,S)‐dihydroxy‐8(E)‐octadecenoic acids, when cultivated in a mineral medium using oleic acid as a single carbon source. These compounds were purified, 91 and 96 % respectively, to produce two new families of estolides: trans‐8‐estolides and saturated estolides from the monohydroxylated monomer. trans‐8‐estolides were produced by three different lipases (Novozym 435, Lipozyme RM IM and Lipozyme TL IM) with reaction yields between 68.4 ± 2.1 and 94.7 ± 2.4 % in a solvent‐free medium at 80 °C in 168 h under vacuum. Novozym 435 was found to be the most efficient biocatalyst for both hydroxy‐fatty acids with reaction yields of 71.7 ± 2.3 and 94.7 ± 2.4 %, respectively. Moreover, saturated estolides were also produced from a saturated 10(S)‐hydroxy‐8(E)‐octadecenoic. These estolides were chemically and enzymatically synthesized with Novozym 435, under the previous described reaction conditions with yields of 60.7 ± 2.1 and 71.2 ± 2.3 % respectively. Finally, viscosity, glass transition temperature, decomposition temperatures and enthalpies were determined to characterize both types of estolides. Thermal applications for both types of polyesters were improved since glass transition temperatures were lowered and decomposition temperatures were increased, with respect to their corresponding substrates. 相似文献
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Shan-Shan Jiang Xiao-Na Liang Xin Li Shun-Li Wang Dong-Wen Lv Chao-Ying Ma Xiao-Hui Li Wu-Jun Ma Yue-Ming Yan 《International journal of molecular sciences》2012,13(12):16065-16083
A comparative proteomic analysis of drought-responsive proteins during grain development of two wheat varieties Kauz (strong resistance to drought stress) and Janz (sensitive to drought stress) was performed by using linear and nonlinear 2-DE and MALDI-TOF mass spectrometry technologies. Results revealed that the nonlinear 2-DE had much higher resolution than the linear 2-DE. A total of 153 differentially expressed protein spots were detected by both 2-DE maps, of which 122 protein spots were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified differential proteins were mainly involved in carbohydrate metabolism (26%), detoxification and defense (23%), and storage proteins (17%). Some key proteins demonstrated significantly different expression patterns between the two varieties. In particular, catalase isozyme 1, WD40 repeat protein, LEA and alpha-amylase inhibitors displayed an upregulated expression pattern in Kauz, whereas they were downregulated or unchanged in Janz. Small and large subunit ADP glucose pyrophosphorylase, ascorbate peroxidase and G beta-like protein were all downregulated under drought stress in Janz, but had no expression changes in Kauz. Sucrose synthase and triticin precursor showed an upregulated expression pattern under water deficits in both varieties, but their upregulation levels were much higher in Kauz than in Janz. These differentially expressed proteins could be related to the biochemical pathways for stronger drought resistance of Kauz. 相似文献