bluuebunny/crossref_metadata_2025 huggingface dataset:
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

For 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

Some 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

The 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

To 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

10,11‐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

Lysophospholipids 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

The 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

Variable 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

A 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

Separation 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

The 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

Critical 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

Palm‐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

New 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

An 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

A 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

Critical 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

This 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

Lipase 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

Lesquerolic 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.
Lipase‐catalyzed enrichment of long‐chain polyunsaturated fatty acids
Authors: McNeill Gerald P. , Ackman Robert G. , Moore Stephen R.
Published: November 2006

Lipase hydrolysis was evaluated as a means of selectively enriching long‐chain ω3 fatty acids in fish oil. Several lipases were screened for their ability to enrich total ω‐3 acids or selectively enrich either docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA). The effect of enzyme concentration, degree of hydrolysis, and fatty acid composition of the feed oil was studied. Because the materials that were enriched in long‐chain ω3 acids were either partial glycerides or free fatty acids, enzymatic reesterification of these materials to triglycerides by lipase catalysis was also investigated. Hydrolysis of fish oil by eitherCandida rugosa orGeotrichum candidum lipases resulted in an increase in the content of total ω3 acids from about 30% in the feed oil to 45% in the partial glycerides. The lipase fromC. rugosa was effective in selectively enriching either DHA or EPA, resulting in a change of either the DHA/EPA ratio or the EPA/DHA ratio from approximately 1:1 to 5:1. Nonselective reesterification of free fatty acids or partial glycerides that contained ω3 fatty acids could be achieved at high efficiency (approximately 95% triglycerides in the product) by using immobilizedRhizomucor miehei lipase with continuous removal of water.
Solvent polarity influences product selectivity of lipase‐mediated esterification reactions in microaqueous media
Authors: Kuo S. ‐J. , Parkin K. L.
Published: November 2006

Esterification reactions were evaluated by using lipases fromRhizomucor miehei (Lipozyme IM20) andPseudomonas cepacia (PS‐30) with equimolar levels (1.77 mmol) of undecanoic acid and glycerol or 1,3‐propanediol (1,3‐PD) or 1,2‐propanediol (1,2‐PD) in organic solvents of log P (partition coefficient between 1‐octanol/water) values of (−0.33–4.5. Reaction yields (percentage of esterified undercanoate) with glycerol ranged from 1.4 to 72%, with greatest yields observed in solvents of log P 4.0–4.5 for Lipozyme, whereas the PS‐30 lipase was similarly effective (27–38% yield) over the full range of solvent polarities. For both enzymes, as solvent apolarity increased, so did the extent of acylation of glycerol in the final product mixture. Reaction yields with 1,3‐PD ranged from 8.1 to 64% for Lipozyme and from 18 to 84% for PS‐30 lipase, with greatest yields observed for both enzymes in solvents of log P values in the range 1.2–5.0. For both lipases, the shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,3‐PD/monoacylated‐1,3‐PD in the product mixture. Reaction yields with 1,2‐PD ranged from 2.5 to 45% for Lipozyme and from 12 to 52% for PS‐30 lipase, with greatest yields observed in solvents of log P values in the ranges 1.4–1.9 and 1.4–4.5, respectively. The shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,2‐PD: monoacylated‐1,2‐PD in the product mixture, except for Lipozyme in the three most apolar solvents (log P of 3.5–4.5) in which there was a general attenuation of activity. These results suggest the existence of a solvent polarity influence on reaction product selectivity in multiproduct reactions, which can be partially explained on the basis of differential solvation and extraction properties of solvents.
Biocatalytical synthesis and monolayer studies of multiple hydroxylated wax esters
Authors: Lokotsch Wolfram , Lang Siegmund , Möbius Dietmar , Wagner Fritz
Published: November 2006

The continuous production of aleuritic acid decyl ester has been investigated with LipozymeTM as biocatalyst in a fixed‐bed reactor. To avoid the limiting effects of mean substrate solubility, the direct synthesis without organic solvents was chosen, whereby a yield of 90% was obtained depending on the residence time. A comparison of different reaction paths to synthesize a centrally dihydroxylated decyl ester indicated a preference for transesterification of the methyl ester. Under external compression, the interfacial behavior of several enzymatically produced hydroxy wax esters was determined with a Langmuir film balance to find a structure/efficiency relationship. Brewster‐angle microscopy allowed direct visualization of a wax ester monolayer at the air/water interface.
Biotransformation of saturated monohydroxyl fatty acids to 2‐tetrahydrofuranyl acetic acid derivatives: Mechanism of formations and the biological activity of 5‐n‐hexyl‐tetrahydrofuran‐2‐acetic acid
Authors: Huang J. ‐K. , Dowd P. F. , Keudell K. C. , Klopfenstein W. E. , Wen L. , Bagby M. O. , Lanser A. C. , Norton R. A.
Published: November 2006

Transformation of 12‐hydroxyoctadecanoic acid (12‐HOA) to 5‐n‐hexyl‐tetrahydrofuran‐2‐acetic acid (5‐HTFA) byBacillus lentus NRRL B‐14864 (B‐14864) was carried out in the presence or absence of oligomycin, 2‐bromooctanoic acid (2‐BA), or sodium azide. In addition, several saturated and monounsaturated monohydroxyfatty acids, saturated monooxofatty acids, and monounsaturated fatty acid were used as substrates for transformation reactions by B‐14864 or corynebacterium FUI‐2. Methyl esters of the transformation products were analyzed by gas chromatography and gas chromatography/mass spectroscopy. Various γ‐lactones and tetrahydrofuran fatty acid derivatives were conversion products when saturated monohydroxyfatty acids were used as substrates; the production of 5‐HTFA from 12‐HOA by B‐14864 cells was completely inhibited in the presence of high concentration of oligomycin, 2‐BA, or sodium azide; and fatty acid β‐oxidation metabolic intermediates, 6‐hydroxydodecanoic, 4‐oxododecanoic, and 4‐oxodecanoic acids were products when 12‐HOA, 10‐oxo‐, and 12‐oxooctadecanoic acids were used as substrates. Our results suggest that the production of 5‐HTFA from 12‐HOA by B‐14864 was through the fatty acid β‐oxidation pathway. Three‐day‐old driedfruit beetle pupae were topically treated with 5‐HTFA to test for juvenile hormone activity, and 5‐HTFA was found to possess juvenile hormone‐like activity in pure form but not when it was diluted to 10%.
Glyceride synthesis in a solvent‐free system
Authors: Fureby Anna Millqvist , Adlercreutz Patrick , Mattiasson Bo
Published: November 2006

Synthesis of partial glycerides in a solvent‐free system has been investigated with various acyl donors and glycerol as substrates and a 1,3‐specific immobilized lipase to catalyze the reaction. Capric acid was the most efficient acyl donor, compared with ethyl caprate and tricaprin. However, to obtain a high yield of dicaprin and a low amount of tricaprin, ethyl caprate was the acyl donor of choice. The composition of the product mixture was determined by the ratio of ethyl caprate to glycerol; a molar ratio of 3∶1 was optimum for dicaprin synthesis. The water content in glycerol did not influence the final yield of dicaprin, but initial production of capric acid increased with increasing water content. The reaction was found to be controlled entirely by external mass transfer. The yield of diglyceride could be increased from 70 to 90% by lowering the reaction temperature, so that the diglyceride precipitated during the reaction.
Diesel fuel as a solvent for the lipase‐catalyzed alcoholysis of triglycerides and phosphatidylcholine
Authors: Haas Michael J. , Scott Karen M.
Published: November 2006

The abilities of three commercially available lipases—Lipozyme IM 20, Amano PS‐30, and Amano CE—to synthesize fatty acid ethyl esters via the alcoholysis of soy triglycerides (TG) and phosphatidylcholine (PC) in grade No. 2 diesel fuel were investigated. All three enzyme preparations were active in water‐saturated diesel fuel, synthesizing fatty acid esters from both TG and PC. Response surface methodology, based on a Modified Central Composite design, was employed to examine the coordinate effects of lipid, water, and ethanol concentrations on enzyme activities and to identify conditions yielding maximum alcoholysis. For all three enzymes, optimal activities toward TG occurred at added water concentrations of less than 0.3 M. With PC as substrate, optimal enzyme activities occurred at added water concentrations as much as tenfold greater than this, and the amount of water required for maximum activity was proportional to the substrate concentration. For both substrates the enzyme activities were generally reduced as ethanol concentrations rose. The exceptions to this were the Lipozyme‐TG combination, where activity increased with increasing ethanol concentrations, and the PS‐30‐PC combination, where activity was roughly constant across the range of water and ethanol concentrations examined. Hydrolytic activities of the enzymes in aqueous reactions were poor predictors of transesterification activity in organic solvent: the aqueous hydrolytic activities of CE and PS‐30 toward TG were roughly comparable, and 25 to 50 times greater than that of IM 20. However, in the alcoholysis of TG in diesel fuel the order of activities was PS‐30>IM 20>CE. The activities of Lipozyme and CE toward PC were similar to one another, and PS‐30 was considerably less active on this substrate. CE lipase was more active toward PC than toward TG. Lipozyme displayed comparable activity toward the two substrates. PS‐30 was considerably more active on TG than on PC. Degrees of conversion were consistent with the transesterification of only one fatty acid of TG, and slightly greater than one fatty acid for PC. Preliminary studies indicated that for CE and PS‐30, but not for Lipozyme IM 20, the degree of conversion of TG, but not PC, could be significantly increased by the further provision of ethanol. Expansion of this work could lead to a method for the production of simple fatty acid esters, which are suitable as diesel fuels, from multicomponent agricultural materials containing TG and PC.
Selection of surfactant‐modified lipases for interesterification of triglyceride and fatty acid
Authors: Mogi Ken‐ichi , Nakajima Mitsutoshi
Published: November 2006

Interesterification of tripalmitin and stearic acid inn‐hexane was investigated with surfactant‐modified lipases. Various kinds of lipases and surfactants were screened for high interesterification activity of the modified lipases. The modified‐lipase hydrophile‐lipophile balance value and fatty acid group of the surfactants. The modified lipase obtained fromRhizopus japonicus with sorbitan monostearate as surfactant had the highest activity in then‐hexane system. The interesterification activity of the selected modified lipase in molten substrates at 75°C without solvents was the same as that in then‐hexane system at 40°C.
Enzymatic esterification of glycerol III. Lipase‐catalyzed synthesis of regioisomerically pure 1,3‐sn‐diacylglycerols and 1 (3)‐rac‐monoacylglycerols derived from unsaturated fatty acids
Authors: Waldinger Claudia , Schneider Manfred
Published: November 2006

Lipases that display high regioselectivities and broad substrate tolerance were used as catalysts for the efficient esterification of glycerol under the conditions of irreversible acyl transfer. A variety of unsaturated fatty acids, such as oleic, linoleic, erucic, ricinolic, hydroxystearic and coriolic acid, were used for this purpose in the form of their vinyl esters. Suitable biocatalysts were chosen on the basis of systematic screening experiments regarding their regioselectivities (RE) and substrate tolerances. Distinct differences were found and expressed in numerical RE values as a measure for differences of these biocatalysts as being specific, selective, and nonspecific. Based on these experiments, a variety of molecules were synthesized on a preparative scale (>150 mmol) in good yield (ca.85%) and with high regioisomerical purities (>95% RE).
Synchrotron radiation X‐ray diffraction study on phase behavior of PPP‐POP binary mixtures
Authors: Minato A. , Ueno S. , Yano J. , Wang Z. H. , Seto H. , Amemiya Y. , Sato K.
Published: November 2006

The phase behavior of thesn‐1,3‐dipalmitoyl‐2‐oleoylglycerol (PPP‐POP) binary mixture system was studied by powder X‐ray diffraction with synchrotron radiation and by differential scanning calorimetry. The results showed that the immiscible phases were observed in metastable and in the most stable forms. In particular, synchrotron X‐ray diffraction enabled us to reveal the monotectic nature of α as a kinetic phase behavior. The equilibrium phase diagram of the PPP‐POP mixture is divided into two regions. In POP concentration ratios below 40%, solid‐state transformation from α to β was observed, indicating that the α‐β transition of PPP was promoted in the presence of POP. By contrast, the polymorphic transition proceeds from α to β through the occurrence of the intermediate β′ form at POP concentration ratios above 50%.
Supercritical fluid extraction of sunflower seed oil with CO2‐ethanol mixtures
Authors: Cocero María José , Calvo Lourdes
Published: November 2006

The effect of ethanol addition to supercritical carbon dioxide (SC‐CO2), up to 20%, on sunflower seed oil extraction over the range of 150 to 350 bars and 42 to 80°C was studied. A nonrecirculating home‐made bench‐scale system was used as extraction equipment. The oil‐SC‐CO2‐ethanol mixture was reduced to atmospheric pressure in a test tube, where two phases, oil and ethanol, were obtained and ethanol‐saturated CO2 was liberated to the atmosphere. Results show that sunflower oil solubility in SC‐CO2 greatly increases with addition of ethanol as entrainer over the whole range of pressure and temperature conditions. Some phospholipids are co‐extracted at levels directly proportional to the added ethanol. Moreover, a large amount of phospholipids was recovered in the ethanolic phase. Acidity of the extracted oil with ethanol as entrainer was lower than that without alcohol. Part of the free fatty acids was found in the ethanolic phase.
Direct measurement of thermal fat crystal properties for milk‐fat fractionation
Authors: Breitschuh Birgit , Windhab Erich J.
Published: November 2006

The temperature dependency of the solid‐fat content of a fat is important for predicting the consistency of the final product and for process control. Two direct analytical methods for determining the solid‐fat content and the melting characteristics of milk‐fat fractions have been developed. The fractions are analyzed during crystallization, and the results give reproducible information about the thermal behavior of the fractions and the actual crystal amount in the suspensions. The results are obtained within minutes, and no separation of the fractions before the measurement is necessary. New ways of reducing process time are proposed. It is possible to adapt crystallization time to seasonal variations of the initial milk fat and to the required properties of the final product. Partially crystallized milk fat was directly measured in a calorimeter and a pulsed nuclear magnetic resonance spectrometer. The data showed good correlations and even more accurate results than the conventional methods. The calorimetric method makes it possible to detect polymorphic changes and co‐crystallization in the crystals so that the influence of processing parameters, such as energy input, on crystallization behavior can be investigated.
Conifer seed oils: Distribution of Δ5 acids between α and β chains by13C nuclear magnetic resonance spectroscopy
Authors: Gunstone Frank D. , Wolff Robert L.
Published: November 2006

Nine seed oils from three different conifer families, already examined by gas chromatography and known to contain diene, triene, and tetraene C18 and C20Δ5 acids, have been reexamined by high‐resolution13C nuclear magnetic resonance spectroscopy. The Δ5 acids are apparent only in the α‐chains. This location is independent of chainlength, double‐bond number, and the species considered and is probably a general factor of conifer seed oils. The spectra confirm the presence of oleic, linoleic, α‐linolenic, and of Δ5 acids and give quantitative information about (total) n‐6, n‐3, and Δ5 acids that is in accord with that obtained by gas chromatography.
Characterization of oleoyl‐12‐hydroxylase in castor microsomes using the putative substrate, 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine
Authors: Lin Jiann‐Tsyh , McKeon Thomas A. , Goodrich‐Tanrikulu Marta , Stafford Allan E.
Published: November 2006

We have characterized the oleoyl‐12‐hydroxylase in the microsomal fraction of immature castor bean using the putative substrate, 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (2‐oleoyl‐PC). Previous characterizations of this enzyme used oleoyl‐CoA as substrate and relied on the enzyme transferring oleate from oleoyl‐CoA to lysophosphatidylcholine to form 2‐oleoyl‐PC (acyl‐CoA:lysophosphatidylcholine acyltransferase) in addition to oleoyl‐12‐hydroxylase. The present assay system and characterization use 2‐oleoyl‐PC as substrate (oleoyl‐12‐hydroxylase alone). Use of the actual substrate for assay purposes is important for the eventual purification of the oleoyl‐12‐hydroxylase. Ricinoleate (product of oleoyl‐12‐hydroxylase) and linoleate (product of oleoyl‐12‐desaturase) were identified as metabolites of oleate of 2‐oleoyl‐PC by high‐performance liquid chromatography and gas chromatography/mass spectrometry. The activity of oleoyl‐12‐hydroxylase in the microsomal fraction reached a peak about 44 d after anthesis of castor, while the activity of oleoyl‐12‐desaturase reached a peak about 23 d after anthesis. The optimal temperature for the oleoyl‐12‐hydroxylase was about 22.5°C, and the optimal pH was 6.3. Catalase stimulated oleoyl‐12‐hydroxylase while bovine serum albumin and CoA did not activate oleoyl‐12‐hydroxylase. The phosphatidylcholine analogue, oleoyloxyethyl phosphocholine, inhibited the activity of oleoyl‐12‐hydroxylase. These results further support the hypothesis that the actual subtrate of oleoyl‐12‐hydroxylase is 2‐oleoyl‐PC.
Effects of β‐lactam antibiotics on intestinal microflora and bile acid metabolism in rats
Authors: Hashimoto Shigeru , Igimi Hirotsune , Uchida Kiyohisa , Satoh Takashi , Benno Yoshimi , Takeuchi Nozomu
Published: November 2006

Wistar male rats were treated for six days with broad spectrum β‐lactam antibiotics, latamoxef, and cefotaxime. On the seventh day, the number of fecal anaerobic microbes decreased, total fecal bile acids decreased, and bile acid pools increased. Secondary bile acids such as β‐hyocholic, hyodeoxycholic, lithocholic, and deoxycholic acids decreased in the feces while the primary bile acids, cholic, β‐muricholic, and chenodeoxycholic acids, became predominant. Coprostanol, a microbial metabolite of cholesterol, also disappeared from the feces during the treatment. The cecum enlarged to almost twice the size of that in control rats, whereas the liver weight was not significantly changed. After treatment was stopped, the number of fecal microbes returned to the initial counts within a week, but restoration of bile acid and cholesterol metabolism required at least three weeks.
Blood lipid docosahexaenoic and arachidonic acid in term gestation infants fed formulas with high docosahexaenoic acid, low eicosapentaenoic acid fish oil
Authors: Innis Sheila M. , Auestad Nancy , Siegman Joel S.
Published: November 2006

The effect of fish oil high in docosahexaenoic acid (22∶6n−3) and low in eicosapentaenoic acid (20∶5n−3) in formula on blood lipids and growth of full‐term infants was studied. Infants were fed formula with about 15% oleic acid (18∶1), 32% linoleic acid (18∶2n−6), 4.9% linolenic acid (18∶3n−3) and 0, 0.10 or 0.22% 22∶6n−3, or 35% 18∶1, 20% 18∶2n−6, 2.1% 18∶3n−3 and 0, 0.11 or 0.24% 22∶6n−3 from 3 d to 16 wk of age (n=16, 18, 17, 21, 17, 16, respectively). The formulae had <0.1% 20∶5n−3 and no arachidonic acid (20∶4n−6). Breast‐fed infants (n=26) were also studied. Plasma phospholipid and red blood cell (RBC) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) fatty acids were determined at 3 d and 4, 8, and 16 wk of age. These longitudinal analyses showed differences in blood lipid 22∶6n−3 between breast‐fed and formula‐fed infants depending on the feeding duration. At 16 wk, infants fed formula with 0.10, 0.11% 22∶6n−3, or 0.22% 22∶6n−3 had similar 22∶6n−3 levels in the plasma phospholipid and RBC PC and PE compared with breast‐fed infants and higher 22∶6n−3 than infants fed formula without 22∶6n−3. Formula with 0.24% 22∶6n−3, however, resulted in higher plasma phospholipid 22∶6n−3 than in breast‐fed infants at 16, but not 4 or 8 wk of age. Plasma and RBC phospholipid 20∶4n−6 was lower in formula‐fed than breast‐fed infants, but no differences in growth were found. Higher blood lipid C20 and C22 n−6 and n−3 fatty acids in infants fed formula with 20% 18∶2n−6 and 2.4% 18∶3n−3 compared with 32% 18∶2n−6 and 4.9% 18∶3n−3 show the increase in blood lipid 22∶6n−3 in response to dietary 22∶6n−3 depending on other fatty acids in the formula.
Diversity of the polar lipids of the food‐borne pathogenListeria monocytogenes
Authors: Mastronicolis Sofia K. , German J. Bruce , Smith Gary M.
Published: November 2006

Listeria monocytogenes is a Gram‐positive bacterium that can adapt to high salinity and cold. Because the membrane lipids may play a role in its survival and adaptation, we have examined the polar lipids ofL. monocytogenes. Extraction of total lipids fromL. monocytogenes yielded 7±1 mg/mL wet cells. Polar lipids represented 64% of total lipids and contained 9% lipid‐phosphorus. Polar lipids were separated into 14 components by two‐dimensional thin‐layer chromatography. Eight components (88% of polar lipids) contained lipid‐phosphorus; among these was one major component (34% of polar lipids). Two other phospholipids were ninhydrin‐positive components and accounted for 15% of the polar lipids. Orcinol staining revealed two glyco‐ or sulfo‐lipids accounting for 9% of polar lipids. Five components (4% of polar lipids) were amino components free of phosphorus. The major component contained 46% of its fatty acids as 15:0anteiso, 24% as 17:0anteiso, and 11% as 15:0iso. The fatty acid profile of the remaining polar lipids was variable, consisting primarily of 16:0, 18:0, 15:0anteiso, and 17:0anteiso. Their unsaturation level was ≤20%; however, the major phosphoaminolipid component was 46% unsaturated. The ratios of 15:0anteiso/17:0anteiso and 15:0anteiso/15:0iso were similar in all classes, averaging 1.5 and 4.5, respectively. Since the adaptation process to stressful environments involves activation of a membrane transport system for the protectant glycine betaine, the membrane lipids may play a role in enabling transport.
An improved ultracentrifugation method for the separation of cholesterol carriers in bile
Authors: Ayyad Nariman , Cohen Bertram I. , Ohshima Akira , Mosbach Erwin H.
Published: November 2006

Vesicles and micelles, the major carriers of cholesterol in bile, play a role in the formation of cholesterol gallstones. A simple and rapid ultracentrifugation method was developed to isolate these biliary cholesterol carriers when only microliter amounts of bile were available. The proposed method employs a 46 to 0% sucrose density gradient, a NVT90 near‐vertical rotor, and a centrifugation time of one hour. As little as 25 μL of bile can be used with no disruption of the carriers. The method was validated by comparison with gel filtration column chromatography using 6 mM taurocholate in the elution buffer. The sucrose linear density gradient ultracentrifugation procedure described here is simple, fast, and compares favorably with the gel filtration chromatography method for the separation of cholesterol carriers from bile.
Effect of degree of unsaturation in dietary fatty acids on arachidonic acid mobilization by peritoneal macrophages
Authors: Mitjavila María T. , Rodríguez María C. , Sáiz María P. , Lloret Sergio , Moreno Juan J.
Published: November 2006

Cells from rats fed with a tripalmitin diet showed a depletion of phospholipid arachidonate and n‐3 fatty acids such as eicosapentaenoic and docosahexaenoic acids (EPA and DHA). In rats fed fish oil diet, a significant reduction in archidonic acid (AA) content was observed whereas EPA and DHA were incorporated into membranes lipids. These changes in lipid composition of membranes did not affect cellular adherence, phagocytic capability, or [3H]AA incorporation. However, both tripalmitin and fish oil diets induced a decrease in [3H]AA mobilization stimulated by 4β‐phorbol‐12‐myristate 13‐acetate, A23187, or opsonized‐zymosan in rat peritoneal macrophages. These results demonstrate that the antiinflammatory effects of essential fatty acids deficiency or n‐3 enrichment diets may be associated with a decreased AA mobilization in resident rat peritoneal macrophages treated with proinflammatory agents.