bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of temperature on lipid classes and their fatty acid profiles inLipomyces starkeyi
Authors: Suutari M. , Rintamäki A. , Laakso S. 
Published: November 2006

AbstractThe effect of environmental temperature on fatty acid contents of major lipid classes was determined inLipomyces starkeyi at 30, 20, and 10°C. When the temperature was reduced from 30 to 20°C, the linolenic acid content increased in phosphatidylcholine but fell with further reduction to 10°C. The relative contribution of phosphatidylcholine and phosphatidylethanolamine that contained the next lowest‐melting fatty acids, palmitoleic and linoleic acids, increased on lowering the temperature from 20 to 10°C and, concomitantly, the combined phosphatidylinositol and phosphatidylserine fraction decreased, and triacylglycerols were accumulated.
Analysis ofcis‐ andtrans‐fatty acid isomers in hydrogenated and refined vegetable oils by capillary gas‐liquid chromatography
Authors: Duchateau G. S. M. J. E. , van Oosten H. J. , Vasconcellos M. A. 
Published: November 2006

AbstractFor quantitation ofcis‐ andtrans‐fatty acid isomers, infrared (IR) spectroscopy, gas‐liquid chromatography (GLC) on highly polar stationary phases or the combination (GLC‐IR) may be used. IR offers the advantage of simplicity and speed, but the lower determination limit of 5% and the lack of detailed information limit its use. Detailed fatty acid information, required for, e.g., food‐labeling purposes, can only be obtained with GLC methods. Most of the GLC methods are optimized for partially hydrogenated samples. AOCS Official Method Ce 1c‐89 prescribes a single, highly polar stationary phase, SP2340, but underestimates the amount oftrans isomers due to 18∶1 positional isomer overlap. The combined GLC‐IR method may circumvent this problem but at the cost of time, effort, and precision.Trans isomers in refined (deodorized or stripped) oils are different in type and levels from isomers in partially hydrogenated oils; theirtrans isomers are mono‐trans trienoic and dienoic isomers, occurring at levels up to about 1–3%. GLC conditions for hydrogenated samples are often not suitable for refined oils because of overlap problems, but this time in the 18∶3 region. Through careful selection of stationary phase and temperature program optimization (Drylab®GC), we have developed a single method that is suitable for hydrogenated, as well as refined, processed oils. The accuracy was checked withcis andtrans fatty acid fractions isolated by silverion exchange high‐performance liquid chromatography. Thetrans values obtained with the optimized method are in good agreement with the results obtained for the isolated fractions. We propose that recommended methods describe GLC conditions in terms of separation criteria rather than recommending only a fixed combination of stationary phase and temperature program.
N,N′‐ethylenediyl‐bis‐alkanamides: Differential scanning calorimetry studies
Authors: Pryce‐Jones R. H. , Eccleston G. M. , Abu‐Bakar B. B. , Grant K. M. 
Published: November 2006

AbstractSome longer‐chainbis‐alkanamides of ethylenediamine have been synthesized and crystallized for use as potential standards for the measurement of decomposition of aminophylline suppositories. The thermal properties of the compounds have been investigated by differential scanning calorimetry (DSC). Each of the compounds was found to give two endotherms. The endotherms at the higher temperature corresponded to the melting temperatures. However, over the homologous series, the upper endotherm demonstrated paradoxical behavior in that the temperature decreased as the length of the alkanoyl chain, and hence the relative molecular mass, increased. The endotherm at the lower temperature could not be attributed to any visible change in the physical or microscopic state of the crystals. It behaved more as expected from the thermal properties of other fatty acid derivatives, such as the esters, mono‐, di‐, and triglycerides, in that the temperature increased as the alkanoyl chainlength increased. Cooling the compounds to 25°C after this first DSC run and then reheating under the same conditions showed that the upper endotherm remained the same but that a number of new endotherms replaced the lower endotherm. The endotherms found during this repeat run had lower enthalpies per gram than were obtained from the freshly crystallized materials. A possible structure for the crystals is presented. A model is proposed with hydrogen bonding and van der Waals bonding between adjacent molecules where differential breaking of these bonds causes the two initial endotherms.
Effects of sucrose ester on the kinetics of polymorphic transition in hydrogenated sunflower oil
Authors: Herrera M. L. , Marquez Rocha F. J. 
Published: November 2006

AbstractThe effect of a commercial emulsifier, sucrose ester, on the crystallization kinetics of hydrogenated sunflowerseed oil was studied by means of an optical method. Induction times were measured for hydrogenated oil with the addition of 0.01, 0.05, and 0.1 wt% sucrose ester. This emulsifier delayed nucleation, thus affecting the formation of critical nuclei and prolonging induction times. Kinetics of the β’→β polymorphic transition was followed by X‐ray diffractometry. Addition of the emulsifier delayed the appearance of the signal at 4.6 Å. Moreover, longer times were needed to complete the transition. The kinetic model chosen to describe the transition process was based on the theory of Avrami. Avrami’s exponentn was approximately 1 in all cases. Then value was in agreement with the fact that only one β’ pattern was found. The β form could not be obtained directly from the melt, and it is unlikely that the β’→β transition occurred through a melt‐mediated mechanism. Transition was hindered by the rigidity of the sucrose ester structure.
Participation of thecis‐12 ethylenic bond tocis‐trans isomerization of thecis‐9 andcis‐15 ethylenic bonds in heated α‐linolenic acid
Authors: Wolff Robert L. , Nour Mohamed , Bayard Corinne C. 
Published: November 2006

AbstractTo understand thecis‐trans isomerization reaction of ethylenic bonds in heated octadecatrienoic acids (occurring during industrial deodorization of oils), we have prepared a mixture ofcis‐9,cis‐12,cis‐15, andcis‐9,cis‐15 18:2 acids by partial hydrazine reduction ofcis‐9,cis‐12,cis‐15 18:3 acid present in linseed oil. This mixture (as fatty acid methyl esters) was heated under vacuum at 270°C for 2.25 h. The two methylene‐interrupted acids isomerize at a similar rate under such conditions, but the nonmethylene‐interruptedcis‐9,cis‐15 18:2 acid remains unchanged. This means that the mechanism of isomerization does not involve a direct interaction between the two external ethylenic bonds as previously hypothesized. The centralcis‐12 ethylenic bond is apparently necessary for the isomerization of the two externalcis‐9 andcis‐15 ethylenic bonds. However, this bond is itself rather protected against isomerization in the originalcis‐9,cis‐12,cis‐15 18:3 acid which is mainly isomerized totrans‐9,cis‐12,trans‐15,cis‐9,cis‐12,trans‐15, andtrans‐9,cis‐12,cis‐15 18:3 acids. Thecis‐9,trans‐12,cis‐15 18:3 isomer is less than 10% of totaltrans isomers of α‐linolenic acid. As a general rule, only one of the two double bonds in a methylene‐interrupted diethylenic system can undergocis‐trans isomerization when submitted to heat treatment, at least for temperatures equal to or less than 270°C.
Synthesis of a palm‐based star‐shaped hydrocarbonvia oleate metathesis
Authors: Choo Yuen‐May , Ooi Kay‐Eng , Ooi Ing‐Hong , Tan Daniel D. H. 
Published: November 2006

Abstract10,11‐Dioctyleicosane, a star‐shaped hydrocarbon, has been successfully synthesized from 9‐octadecene (a product from metathesis of methyl oleate or ethyl oleate) through dimerization followed by hydrogenation. The product was determined by13C nuclear magnetic resonance spectroscopic and gas chromatography/mass spectrometric techniques. This hydrocarbon likely exhibits lubricating properties that can be used as high‐performance functional fluids in automotive lubrication. We also report the presence of a novel product, a trimer that was formed during the synthesis.
Phospholipase A2‐catalyzed hydrolysis of lecithin in a continuous reversed‐micellar membrane bioreactor
Authors: Morgado M.A.P. , Cabral J.M.S. , Prazeres D.M.F. 
Published: November 2006

AbstractLysophospholipids and free fatty acids produced by lecithin hydrolysis are important natural compounds with high potential for application in the food, chemical, and pharmaceutical industries. In this work, the enzymatic hydrolysis of lecithin (essentially phosphatidylcholine) catalyzed by porcine pancreatic phospholipase A2 (phosphatide 2‐acyl‐hydrolase, EC 3.1.1.4), encapsulated in mixed reversed micelles of lecithin andbis(2‐ethylhexyl) sodium sulfosuccinate (AOT) in isooctane, was carried out in a continuous reversed‐micellar membrane bioreactor. A tubular ceramic membrane with a 10,000 molecular weight (MW) cutoff was installed in an ultrafiltration module to retain the phospholipase A2 (MW 14,000) and to continuously separate the products from the reaction media. Water and co‐factor (Ca++)‐containing reversed micelles of lecithin/AOT in isooctane were supplemented to the reactor to compensate for the permeation of reversed micelles and to continuously supply the substrate. The influence of relevant parameters, such as substrate, AOT and enzyme concentrations, water content and fluid hydrodynamics, on the performance of the ultrafiltration membrane bioreactor was investigated. Fluid axial velocity and substrate concentration were the major factors that affected the transport processes through the membrane. Permeate flow rate increased significantly with fluid axial velocity and decreased with substrate concentration; on the other hand, water and enzyme concentrations were identified as critical parameters for the final conversion of lecithin. The relationship between productivity and normalized residence time was analyzed for each set of experimental parameters tested. Operational stability of the bioreactor was tested in a long‐term operation to confirm the high stability of this catalytic system.
Methanolysis of seed oils in flowing supercritical carbon dioxide
Authors: Jackson Michael A. , King Jerry W. 
Published: November 2006

AbstractThe direct methanolysis of triglycerides in flowing supercritical carbon dioxide by an immobilized lipase is described. The reaction system consists of two syringe pumps for substrate addition and another two syringe pumps for delivering CO2 at 24.1 MPa. Corn oil is pumped into the carbon dioxide stream at a rate of 4 μL/min, and methanol is pumped at 5 μL/min to yield fatty acid methyl esters (FAME) at >98% conversion. Direct methanolysis of soy flakes gives FAME at similar yields. This combined extraction/reaction is performed at 17.2 MPa and 50°C. The fatty acid profiles obtained for these seed oils matches those obtained by classical chemical synthesis.
Effect of mixing leaves with olives on organoleptic quality of oil obtained by centrifugation
Authors: Di Giovacchino L. , Angerosa F. , Di Giacinto L. 
Published: November 2006

AbstractVariable quantities of leaves were added to ripe olives prior to extraction to determine their effect on the quality of the resulting olive oil. The addition of 1–3% w/w leaves improved the organoleptic quality. An increase intrans‐2‐hexenal aldehyde content occurred, giving the pleasant flavor of “freshly cut grass.” This compound was produced by the enzymatic breakdown of 13‐L‐hydroperoxide of linolenic acid in leaf homogenates.
A simple and rapid polarimetric method for quantitative determination of castor oil
Authors: Babu S. , Sudershan R. V. , Sharma R. K. , Bhat Ramesh V. 
Published: November 2006

AbstractA simple and rapid polarimetric method is developed for quantitation of adulteration of castor oil in edible oils such as cottonseed, coconut, mustard, olive, palm, peanut, rice bran, safflower, soybean, and sunflower. The method is based on the optical activity of ricinoleic acid (12‐hydroxy octadecenoic acid), a major constituent of castor oil. There is a good correlation between optical rotation and castor oil content in admixtures above 5%. Highly colored and viscous oils interfere in the measurement of optical activity. The method is highly specific and cost‐effective. No solvents and chemicals are required for the analysis because no sample processing is involved in the present method.
Separation of fatty acids/triacylglycerol by membranes
Authors: Krishna Kumar N. S. , Bhowmick D. N. 
Published: November 2006

AbstractSeparation of fatty acids from triacylglycerol by membrane separation technique has been studied. Mixtures of triacylglycerols and fatty acids were extracted with alcohol, and the alcohol extracts were treated for recovery of oil by membrane separation technique. The membranes used were of both cellulosic and noncellulosic types. Polyamide membranes showed better selectivity toward fatty acid separation as compared to cellulose acetate and polysulfone membranes. For groundnut oil/fatty acid/alcohol mixture and a polyamide membrane, the free fatty acid (FFA) concentration in the permeate was 86.82% at 0.7 MPa pressure when the feed had 61.71% FFA. A reasonable permeate flux of 67.36 Im−2h−1 was obtained. Results obtained have been useful in selecting membrane material suitable for such applications.
Correlation between spray cleaning detergency and dynamic surface tension of nonionic surfactants
Authors: Prieto N. E. , Lilienthal W. , Tortorici P. L. 
Published: November 2006

AbstractThe role of temperature and dynamic surface tension (DST) in spray‐cleaning processes in industrial applications was investigated with nonionic surfactants. Relative performance data for various ethoxylates (derived from primary alcohols or nonylphenol) were obtained by a spray‐cleaning method. The spray‐cleaning method was developed to screen and identify optimum surfactants, formulations, and conditions for spray‐cleaning applications. It is introduced here as a means to mimic spray‐cleaning processes by (timed) spraying of a cleaner solution under pressure onto a soiled substrate. Results of this investigation indicated that temperature and DST play major roles in the soil‐removal process. Observed temperature trends are typical of nonionic surfactants’ clouding phenomena. Optimum cleaning was observed at specific temperatures. Also, nonionics with shorter hydrophobes exhibited the best detergency. Spray‐cleaning detergency was compared to the DST because spray cleaning involves a dynamic interfacial process. New interfaces are constantly being created. Results showed that the surfactants with the lowest DST exhibited the best soil removal. This correlation can allow for a fast, cost‐effective means for screening potential candidates and reducing development time for industrial spray‐cleaning applications.
Mixed‐surfactant system of dodecylbenzene sulfonate and alpha‐olefin sulfonate: Micellar and volumetric studies
Authors: Bharadwaj Satish , Ahluwalia J. C. 
Published: November 2006

AbstractCritical micelle concentrations of sodium salts of dodecylbenzene sulfonate, alpha‐olefin (C16) sulfonate, and their mixtures have been evaluated by measuring the surface tensions of solutions at 298.15 K. Interaction parameters for mixed monolayer formation (βσ) and mixed‐micelle formation (βM) have been calculated from the critical micelle concentration data. Densities of solutions of surfactants and their mixtures were measured with a vibrating‐tube densimeter at 298.15 K. Apparent and partial molar volumes have been evaluated from solution density data. Results of the micellar properties have been eplained on the basis of a nonideal multicomponent mixed‐micelle model. The mixed‐surfactant system exhibits synergism in all aspects when the mole fraction of alpha‐olefin sulfonate in the mixture is 0.2. Volumetric properties correlate well, as the partial molar volumes also show a minimum at the same composition of the mixture. Formation of a compact mixed micelle at this composition has been envisaged.
Properties of palm‐oil‐in‐water emulsions: Effect of mixed emulsifiers
Authors: Chow M. C. , Ho C. C. 
Published: November 2006

AbstractPalm‐oil‐in‐water emulsions were prepared with mixtures of Tween 40 and Span 40 in various proportions. Stability and droplet‐size distribution of the emulsions were monitored. Interfacial tensions of the palm oil/water interface were also determined in the presence of these emulsifier mixtures. Emulsifying efficiency of the emulsifier mixtures was assessed. No synergistic effect of Tween 40 (sorbitan monopalmitate with 18–22 moles of ethylene oxide) and Span 40 (sorbitan monopalmitate) was found on interfacial tension. Tween 40 alone (hydrophilic‐lipophilic balance value 15.6) at 1.0% w/w gave palm oil emulsions that were stable for more than 30 d at 60°C. Emulsifier mixtures of Tween 40 and Span 40 with hydrophilic‐lipophilic balance values in the range of 8.0–8.6 produced stable emulsions only at much higher emulsifier‐mixture concentrations. The inherent nature of the oil and the accompanying natural surface‐active materials present in the oil can influence the prevailing conditions at the oil/water interface and alter composition of the interfacial film and hence its stability.
Nonionic amphiphilic compounds from lysine as molecular mimics of lecithins
Authors: Seguer J. , Selve C. , Allouch M. , Infante M. R. 
Published: November 2006

AbstractNew monodisperse nonionic surfactant molecules, based on lysine with two fatty acid chains in the hydrophobic part and one or two polyoxyethylene methoxycapped chains (EOn−Me) in the hydrophilic headgroup, are synthesized as mimics of natural lecithins. Their surface‐activity properties indicate that these compounds have surfactant behavior whose global hydrophobic contribution is comparable to that of one fatty chain.
Synthesis and aggregation behavior of an amphiphilic cobalt (III) complex that coordinates higher diacylglyceryldiamine ligands
Authors: Osanai Shuichi , Konishi Takeshi , Yoshikawa Sadao 
Published: November 2006

AbstractAn amphiphilic cobalt complex that coordinates a higher diacylglycerylethylenediamino group was prepared. They extensively aggregated in aqueous solution upon ultrasonication. Electron microscopy indicated formation of stable bilayer structures, which further formed vesicles and fibrous aggregates. We observed an intermediate state that led to a network morphology in the fusion process of small unilamellar vesicles. Differential scanning calorimetry experiments establiched the presence of the phase transition from gel to liquid crystal for all probes in which a C14 to C18 acyl group was bound. The phase‐transition temperature was elevated with increasing carbon numbers of the acyl group.
Analysis of the dark‐colored impurities in sulfonated fatty acid methyl ester
Authors: Yamada Kaoru , Matsutani Shigeaki 
Published: November 2006

AbstractA fractionally distilled C14−C16 fatty acid methyl ester, derived from palm oil, was sulfonated with gaseous SO3 in a falling film reactor to form an α‐sulfo fatty acid methyl ester (α‐SF; unbleached and unneutralized form). The included dark‐colored impurities were then separated from α‐SF as a diethyl ether‐insoluble matter. After purification by thin‐layer chromatography, the colored species were analyzed by ion‐exchange chromatography, gel‐permeation chromatography, and nuclear magnetic resonance spectrometry. These data suggested that the colored species were polysulfonated compounds with conjugated double bonds. Minor components in the raw fatty acid methyl ester, found by gas chromatography/mass spectrometry, were spiked into the purified methyl palmitate and then sulfonated. The unsaturated methyl ester and hydroxy ester showed the worst color results. The methyl oleate and methyl 12‐hydroxystearate were then sulfonated and analyzed. Deep black products were obtained, which showed the same properties as the colored species in α‐SF. It was concluded that low levels of unsaturated fatty acid methyl esters and hydroxy esters in the fatty acid methyl ester are the main causes of the coloring.
Conductometric and spectrophotometric studies on chromium soap solutions in benzene‐dimethyl formamide
Authors: Mehrotra K. N. , Jain Mamta 
Published: November 2006

AbstractCritical micelle concentrations, degrees of dissociation, and dissociation constants of chromium soaps (laurate, myristate, palmitate, and stearate) in a mixture of benzene and dimethyl formamide (7:3, vol/vol) were determined from conductivity measurements. The soaps behave as simple moderate electrolytes in dilute solutions. Critical micelle concentration, limiting molar conductance and dissociation constants decreased with increasing numbers of carbon atoms in the soap molecules. Spectrophotometric results show that metal‐to‐oxygen bonds in chromium soaps are not purely ionic but have some covalent character.
Lipoxygenase as a versatile biocatalyst
Authors: Gardner Harold W. 
Published: November 2006

AbstractThis review of lipoxygenase and lipoxygenase pathway enzymes focuses on the potential for the efficient production of useful compounds. Although the existence of lipoxygenase has been inown for many years, only recently has there been progress toward understanding the conditions required to improve yields and immobilize its activity. Maintaining a high O2 tension is necessary to obtain good yeilds of hydroperoxides; whereas, partial anaerobic conditions can lead to hydroperoxide decomposition. Fatty hydroperoxides, obtained from lipoxygenase action, can serve as precursors for further transformation by either enzymes or chemical reactions. Well over one‐hundred products from lipoxygenase‐generated hydroperoxides of linoleic acid alone have been described. Examples will be given of the formation of fatty acids with epoxide, hydroxy, ketone, cyclic, and multiple functional groups. The cleavage of fatty hydroperoxides into short‐chain aldehydes and alcohols also will be described. Many of the products have biological activity, suggesting a significant physiological function for lipoxygenase.
Application of immobilized lipase in production of camptosar (CPT‐11)
Authors: Sih John C. 
Published: November 2006

AbstractLipase fromPseudomonas cepaica (Amano, PS‐30) was immobilized on celite and used in organic solvent for the selective acylation of a key alcohol intermediate. The compound was transformed in the synthesis to the anticancer drug Camptosar (CPT‐11). Catalyst activity was influenced by the water content and method used to dry the catalyst. This resolution has been conducted on production scale with equal weight of recyclable catalyst.
Lipase‐catalyzed synthesis of lesquerolic acid wax and diol esters and their properties
Authors: Hayes Douglas G. , Kleiman Robert 
Published: November 2006

AbstractLesquerolic acid was and α,Ω‐diol esters were synthesized via immobilizedRhizomucor miehei lipase‐(Lipozyme) catalyzed esterification of lesquerolic acid and alcoholysis of lesquerella oil. For each wax ester synthesis, when alcohol substrate was present at a slight (ca. 20%) stoichiometric excess and water content was kept low, over 94% of the hydroxy acyl groups were esterified. The extent of reaction and the ratio of monoester to diester produced for α,Ω‐diol reactions was controlled by the solubility of diol in the medium. This latter quantity increased as alcoholysis proceeded due to the formation of partial glycerides and monoesters, which increased the polarity of the medium. Alcoholysis reactions were significantly slower when the medium diol content was above saturation. As the diol chainlength increased, diol solubilization decreased, the ratio of monoester to diester decreased, and the extent of hydrolysis increased. Alcoholysis reactions involving either fatty alcohols or diols suffered from acyl migration, which lowered the purity of lesquerolic acid esters. Several lesquerolic acid esters, synthesized on a preparative scale and purified via column chromatography, were evaluated for their properties: density, viscosity, and melting point. Potential applications for lesquerolic acid esters are discussed.