bluuebunny/crossref_metadata_2025 huggingface dataset:
Acetone‐stable nanofiltration membranes in deacidifying vegetable oil
Authors: Zwijnenberg H. J. , Krosse A. M. , Ebert K. , Peinemann K. V. , Cuperus F. P.
Published: May 2007

The separation of different vegetable oil/solvent mixtures with two types of nanofiltration membranes was studied. One type had a PEBAX [poly(amide‐b‐ether) copolymer] top layer, and the other had a cellulose‐type top layer. These membranes were stable in acetone, ethanol, 2‐propanol, and hexane, all important to the oleochemical industry. Permeabilities were highest for acetone, ±140 L/m2 · h · MPa, and lowest for hexane, which had negligible flux at 2 MPa. Permeabilities decreased with increasing triglyceride or free fatty acid (FFA) concentration. Rejection of triglycerides was constant over the concentration range tested, about 80–95%±5%, depending on the type of membrane used. These properties make membranes applicable for separating triglycerides from acetone by enhancing acetone recovery. Deacidification of triglycerides and FFA mixtures was possible (e.g., fatty acids were retained less than triglycerides). The permeate consisted almost entirely of fatty acids in acetone, and only small traces of triglycerides were found. This makes it feasible to selectively remove the fatty acids and reduce loss of triglycerides normally associated with deacidification.
Model for a cascade continuous epoxidation process
Authors: Hang Xiaomin , Yang Hong
Published: May 2007

A steady‐state mathematical model was developed to analyze the performance of a cascade continuous epoxidation process that was applied to the epoxidation of unsaturated compounds with in‐situ‐formed performic acid. The model equations were nonlinear, and the model prediction was calculated by solving the model equations using a numerical solution procedure. The experimental results supported the model prediction in that good agreement between the model predictions and experimental results was achieved. The model is necessary for precise operation control, process estimation, and operating parameter optimization and regulation, and will provide a theoretical foundation and research method for automatic control and engineering scale‐up.
Ruthenium‐catalyzed metathesis of vegetable oils
Authors: Refvik M. D. , Larock R. C. , Tian Q.
Published: May 2007

A new process for the acyclic diene metathesis of vegetable oils utilizing Grubbs’ ruthenium catalyst (Cy3P)2Cl2Ru = CHPh has been developed. The higher molecular weight oligomers obtained can be separated from the unreacted oil and the lower molecular weight alkene by‐products easily. The reaction proceeds in the absence of solvent, with very low catalyst concentrations (0.1 mole %) under moderate temperatures and low pressures. This process does not require the stringent exclusion of water and oxygen that the previous method (Me4Sn plus WCl6) required. Low pressures appear to favor polymerization by removing the alkene by‐products. The metathesis reaction has been shown to be effective for many unsaturated vegetable oils, although some cases require oil pretreatment with silica gel. This process is effective on a 2–200 g scale. Chromatographic separation and characterization of metathesized soybean oil indicate that the process involves intermolecular and intramolecular carbon‐carbon double‐bond formation.
The chemistry of metathesized soybean oil
Authors: Refvik M. D. , Larock R. C.
Published: May 2007

New materials derived from metathesized soybean oil have been prepared and characterized. Thermal polymerization of metathesized soybean oil in the presence of air results in yellow, brittle gels. These materials display a curious tendency to produce audible popping sounds when exposed to chlorinated organic solvents, such as chloroform or dichloromethane. Complete hydrogenation of metathesized soybean oil has been accomplished in excellent yields utilizing 10% palladium on carbon in dichloromethane. A new, very mild, effective epoxidation procedure for soybean oil, utilizing methyltrioxorhenium (VII) (MTO) and pyridine as the catalyst system and hydrogen peroxide as the oxidant, has been developed. This epoxidation reaction affords excellent yields of epoxidized soybean oil with some control of the degree of epoxidation at very low MTO concentrations (< 0.5 mol%). This reaction is also very effective for the epoxidation of metathesized soybean oil to higher molecular weight epoxidized soybean oil materials.
Synthesis of tetrahydrofuran ring containing oligoethylene glycol ethers from the seed oil of Vernonia anthelmintica
Authors: Singh Sukhprit , Mahajan Sonia , Kaur Harpal
Published: May 2007

A tetrahydrofuran ring containing oligoethylene glycol ethers has been synthesized from the seed oil of Vernonia anthelmintica. The seed oil was reacted with mono‐, di‐, and triethylene glycols in the presence of boron trifluoride etherate, followed by saponification and esterification (MeOH/H+). The oligoethylene glycol ethers thus obtained were epoxidized with perbenzoic acid. The 9,10‐epoxy oligoethylene glycol ethers so formed were intramolecularly cyclized in dry benzene using boron trifluoride etherate as a catalyst to yield the tetrahydrofuran ring containing oligoethylene glycol ethers; methyl 9,12‐epoxy, 10‐hydroxy‐13‐[2‐hydroxyethyl‐1‐oxy]; methyl 9,12‐epoxy,10‐hydroxy‐13‐[2‐hydroxy‐3‐oxapentyl‐1‐oxy] and methyl 9,12‐epoxy,10‐hydroxy‐13‐[8‐hydroxy‐3,6‐dioxaoctyl‐1‐oxy]octadecanoates, respectively.
Thermal analysis of alternative diesel fuels from vegetable oils
Authors: Dunn Robert O.
Published: May 2007

The relatively poor cold‐flow properties of monoalkyl esters of vegetable oils and animal fats (biodiesel) present a major obstacle to their development as alternative fuels and extenders for combustion in direct injection compressionignition (diesel) engines. In this work, differential scanning calorimetry (DSC) heating and cooling curves of methyl soyate (SME), methyl tallowate (TME), SME/TME admixtures, and winterized SME were analyzed. Completion of melt, crystallization onset (Onset), and other temperatures corresponding to melting and freezing peaks were correlated to predict cloud point (CP), pour point (PP), cold filter plugging point (CFPP), and low‐temperature flow test (LTFT) data. Effects of treating methyl esters with cold‐flow improvers were examined. Low‐temperature flow properties of biodiesel may be accurately inferred from subambient DSC analyses of high‐melting or freezing (β‐form) peaks. The temperature of maximal heat flow for freezing peaks gave the best accuracy for predicting CP, PP, and CFPP, while freezing point gave the best accuracy for predicting LTFT. Onset also gave good correlations with respect to predicting PP, CFPP, and LTFT. Cooling scan parameters were more reliable than heating scan parameters.
Plastic performance of soybean protein components
Authors: Sun Xiuzhi Susan , Kim Hak‐Ryang , Mo Xiaoqun
Published: May 2007

Soybean proteins recently have been considered as petroleum polymer alternatives in the manufacture of adhesives, plastics, and various binders. The objective of this work was to characterize the plastic performance of soybean protein components during molding processes. Two major soybean protein fractions, 7S‐rich globulin (7S‐RG) and 11S‐rich globulin (11S‐RG) were separated from defatted soybean flour, and their purity was examined by sodium dodecyl sulfate‐polyacrylamide gel eletrophoresis and high‐performance liquid chromatography. The thermal transition properties of the two fractions at 10% moisture content were 137.6°C for 7S and 163°C for 11S, as analyzed using differential scanning calorimetry (DSC). Plastics were prepared using a hot press at various molding temperatures that were selected based on the proteins’ thermal transition temperatures obtained by DSC. The plastics were evaluated for mechanical properties, water absorption, and microstructure. The plastics prepared with temperatures at or close to the thermal transition temperature showed a smooth, uniform, and complex structure. Results showed that the plastics made from 11S‐RG at its thermal transition temperature were stronger (35 MPa) and had lower water absorption than those made from 7S‐RG at 145°C (26 MPa). The plastics made from the 7S‐ and 11S‐RG mixture had the highest tensile strength (39 MPa) and medium water absorption compared to those made from 7S‐ and 11S‐RG alone. These mechanical properties and water absorption behaviors were significantly affected by molding temperatures. The results obtained from this research indicated that interaction between 7S‐ and 11S‐RG could occur during molding and that thermal transition temperature played an important role in thermal processing of soybean proteins.
Hydrocarbons as markers for identifying postirradiated peanuts
Authors: Park J. Y. , Hwang K. T.
Published: May 2007

Hydrocarbons produced by γ‐radiation of peanuts were analyzed to determine the relationship between irradiation and production of hydrocarbons, and the use of hydrocarbons as markers for identifying postirradiated peanuts. Hydrocarbons in peanuts were determined by a sequential procedure of lipid extraction by hexane, Florisil column chromatography, and gas chromatography. Hydrocarbons C17:1, C16:2, C17:2, and C16:3 were easily detected in peanuts irradiated at 0.5 kGy or higher, but not in unirradiated ones. The hydrocarbons were minimally changed by roasting the irradiated peanuts and were not detected in unirradiated roasted peanuts.
Oxidation of linoleic acid in emulsions: Effect of substrate, emulsifier, and sugar concentration
Authors: Ponginebbi L. , Nawar W. W. , Chinachoti P.
Published: May 2007

Linoleic acid oxidation in oil‐in‐water emulsions stabilized by a nonionic surfactant (Tween‐20) was studied. The emulsion composition was varied at a constant oil droplet size. Lipid oxidation was measured as a function of time in the presence of a catalyst (FeSO4 corbic acid) by two methods: gas chromatographic determination of residual substrate and ultraviolet‐visible spectrophotometric determination of conjugated dienes. Rate of oxidation was influenced by the emulsion composition (relative concentrations of substrate and emulsifier) and especially by the partition of the emulsifier between the interface and water phase. Concentrations of emulsifier exceeding the critical micelle concentration protected the fatty acid against oxidation. Excess surfactant formed micelles and mixed micelles with linoleic acid, which retarded oxidation by diluting the substrate or perhaps by replacing linoleic acid at the interface, making it less accessible to radical attack. The addition of sucrose also had a protective effect, but only up to a certain concentration, indicating the effect may involve factors other than viscosity.
Antioxidant activity of flavonol aglycones and their glycosides in methyl linoleate
Authors: Hopia Anu , Heinonen Marina
Published: May 2007

The antioxidant activities of the flavonol aglycones, quercetin and myricetin, and their selected glycosides were compared in bulk methyl linoleate oxidized at 40°C. Methyl linoleate hydroperoxide formation, hydroperoxide isomer distribution, and ketodiene formation were followed by using high‐performance liquid chromatography (HPLC) analysis. The aglycones, quercetin and myricetin, were consistently more active in bulk methyl linoleate than their glycosides and more active than α‐tocopherol at 500 and 1000 µM. At 50 µM, the order of activity was myricetin > α‐tocopherol > quercetin, and the order of activity of quercetin and its derivatives was quercetin > quercitrin > isoquercitrin > rutin. Myricitrin was slightly less active than myricetin. The sugar moiety was shown to have a marked effect on the antioxidant activity of flavonols. The rhamnoside derivatives, quercitrin and myricitrin, both possessed activity close to that of their corresponding aglycones. The different activities of glycosides could be partly explained by different solubilities and by differences in oxidizability of glycosides containing a monosaccharide or disaccharide at the C3 position. The effect on hydroperoxide isomer distribution indicates that α‐tocopherol was a more effective hydrogen donor than flavonoids, although flavonoids were more effective in inhibiting oxidation of methyl linoleate.
Immobilization of porcine pancreatic lipase on celite for application in the synthesis of butyl butyrate in a nonaqueous system
Authors: de Castro Heizir F. , de Oliveira Pedro C. , Soares Cleide M. F. , Zanin Gisella M.
Published: May 2007

For immobilization of lipase, the use of a porous support material is recommended so that suitable amounts of lipase can be spread on a surface area without conformational changes. In this work, porcine pancreatic lipase was deposited on Celite, either by direct binding from aqueous solution or by deposition from aqueous solution by the addition of organic solvent. The influence of the immobilization procedure on the activities of the derivatives has been studied regarding their ability to synthesize butyl butyrate. The reaction rates were compared with the rate of esterification with free lipase. Better properties were displayed when the immobilized lipase form was prepared in an apolar solvent such as hexane. Under suitable reaction conditions, esterification yields as high as 90% were attained. Batch operational stability tests indicated that no enzyme deactivation occurs after 15 consecutive batches of 24 h each.
Selective binding of docosahexaenoic acid ethyl ester to a silver‐ion‐loaded porous hollow‐fiber membrane
Authors: Shibasaki Akio , Irimoto Yasumitsu , Kim Min , Saito Kyoichi , Sugita Kazuyuki , Baba Takashi , Honjyo Isao , Moriyama Shigeru , Sugo Takanobu
Published: May 2007

Silver ions were loaded at a density of 1 mmol/g onto a sulfonic acid group‐containing porous hollow‐fiber membrane prepared by radiation‐induced graft polymerization of an epoxy group‐containing monomer with subsequent modification by reaction with sodium sulfite. The permeability (i.e., permeation flow rate per inside surface area of the hollow fiber) of 4.6% wt/vol bonito oil ethyl ester solution in water/ethanol (7.5:92.5, vol/vol) was 1.7 m/h at a permeation pressure of 0.1 MPa. Breakthrough curves (i.e., concentration changes of the effluent with increasing effluent volume) obtained with docosahexaenoic acid ethyl ester (DHA‐Et) overlapped, irrespective of the permeation flow rate. This indicates that a higher rate of DHA‐Et adsorption onto the silver ions on the membrane was attained with increasing permeation flow rate. DHA‐Et, which was selectively bound to the membrane, was quantitatively eluted with acetonitrile as an eluent. The adsorption characteristics (i.e., binding rate, selectivity and durability for repeated use) of DHA‐Et using the silver ion loaded porous hollow‐fiber membrane were demonstrated. Feasibility studies will enable comparison of the purification cost of DHA‐Et among the other purification techniques.
Effect of moisture content on immobilized lipase‐catalyzed triacylglycerol hydrolysis under supercritical carbon dioxide flow in a tubular fixed‐bed reactor
Authors: Hampson J. W. , Foglia T. A.
Published: May 2007

Surplus fats and oils were reacted with several lipases under supercritical fluid conditions for the purpose of obtaining value‐added products. Lipases, however, require sufficient moisture content to act as effective biocatalysts. An immobilized lipase from Candida antarctica was chosen to examine the rate of enzyme moisture loss under laboratory ambient conditions and also under supercritical fluid conditions. A more important aspect was to determine the effect of lipase moisture content on the hydrolysis of triacylglycerols under the same supercritical fluid conditions. Under ambient conditions at constant air flow, the immobilized lipase lost water at the rate of 4 to 5%/h, from 48.3% moisture to a final moisture content of 0.2%. Water is known not to be very soluble in supercritical carbon dioxide (SC‐CO2). Nevertheless, under supercritical fluid conditions of 60°C, 4000 psi, and carbon dioxide flow rates of 0.5 or 1 L/min measured as expanded gas, the enzyme moisture loss was approximately 2 to 6%/h. To determine the effect of moisture loss on enzymatic hydrolysis, lipase beds in a tubular reactor with moisture contents of 1.5 to 23.5% were reacted with tripalmitin under supercritical conditions. A lipase with an initial moisture content of 1.5% gave little evidence of hydrolysis whereas those containing 5.4 to 23.5% moisture content resulted in products that contained only palmitic acid and unreacted tripalmitin. Thus, optimal parameters for continuous lipase hydrolysis of tripalmitin require: enough enzyme moisture to compensate for complete substrate hydrolysis; sufficient enzyme moisture for losses due to water solubility in SC‐CO2; temperature and pressure sufficient to solubilize the tripalmitin; high carbon dioxide total flow to solubilize all the tripalmitin; and a relatively large enzyme bed volume to increase the solubilized substrate contact time with the enzyme.
Monitoring chemical interesterification
Authors: Liu Linsen , Lampert Dan
Published: May 2007

Chemical interesterification has long been used to modify oils and fats into functional products. Many chemical compounds can be used as the catalysts, such as sodium metal and sodium methoxide. With addition of the catalyst, the oil turns a well documented distinctive reddish brown. Many believe that this color compound may be the real catalyst in interesterification. The spectral changes of an oil undergoing interesterification were examined in the visible and ultraviolet wavelength ranges. An absorbance peak was found from 320–450 nm. Because this range is the wavelength of blue light, this absorption gives the oil a reddish brown color, the compensated color of blue light. The peak increases as the amount of sodium methoxide increases. To initiate and complete interesterification, the oil absorbance must reach levels of 0.4 and 1.0 at 374 nm, respectively. Controlled partial interesterification is now also possible by controlling the absorbance between 0.4 and 1.0. A novel patent‐pending technology, based on this observation, was developed to monitor the progress of interesterification on‐line using fiber optic technology. The reaction time and the dosage of sodium methoxide used for randomization have been significantly reduced on bench‐scale when using this new tool. Furthermore, the oils interesterified with monitoring have higher oxidative stability and tocopherol contents compared to those by conventional randomization.
Conversion of vegetable oil to biodiesel using immobilized Candida antarctica lipase
Authors: Shimada Yuji , Watanabe Yomi , Samukawa Taichi , Sugihara Akio , Noda Hideo , Fukuda Hideki , Tominaga Yoshio
Published: May 2007

Biodiesel derived from vegetable oils has drawn considerable attention with increasing environmental consciousness. We attempted continuous methanolysis of vegetable oil by an enzymatic process. Immobilized Candida antarctica lipase was found to be the most effective for the methanolysis among lipases tested. The enzyme was inactivated by shaking in a mixture containing more than 1.5 molar equivalents of methanol against the oil. To fully convert the oil to its corresponding methyl esters, at least 3 molar equivalents of methanol are needed. Thus, the reaction was conducted by adding methanol stepwise to avoid lipase inactivation. The first step of the reaction was conducted at 30°C for 10 h in a mixture of oil/methanol (1:1, mol/mol) and 4% immobilized lipase with shaking at 130 oscillations/min. After more than 95% methanol was consumed in ester formation, a second molar equivalent of methanol was added and the reaction continued for 14 h. The third molar equivalent of methanol was finally added and the reaction continued for 24 h (total reaction time, 48 h). This three‐step process converted 98.4% of the oil to its corresponding methyl esters. To investigate the stability of the lipase, the three‐step methanolysis process was repeated by transferring the immobilized lipase to a fresh substrate mixture. As a result, more than 95% of the ester conversion was maintained even after 50 cycles of the reaction (100 d).
Rapid monitoring of transesterification and assessing biodiesel fuel quality by near‐infrared spectroscopy using a fiber‐optic probe
Authors: Knothe Gerhard
Published: May 2007

Vegetable oil esters, particularly methyl esters, are being explored and used as alternative diesel fuel (biodiesel). The transesterification reaction which yields the methyl esters can be monitored for completion by near‐infrared (NIR) spectroscopy using a fiber‐optic probe. Although the NIR method is less sensitive than gas chromatography (GC) for quantifying minor components, by correlation with existing GC or other analytical data, biodiesel fuel quality can be assessed through the NIR method. The NIR method is easier and faster to use than GC.
Preparation of ω‐hydroxynonanoic acid and its ester derivatives
Authors: Kula Jozef , Smigielski Krzysztof , Quang Thuat B. , Grzelak Iwona , Sikora Magdalena
Published: May 2007

Methyl ricinoleate was ozonized in methanol or in acetic acid and the intermediate hydroperoxides were reduced electrochemically on Pb‐cathode to give 9‐hydroxynonanoic acid 1 in high yields. The acid 1 was also prepared by direct castor oil ozonolysis in methanol followed by sodium borohydride reduction of the intermediate hydroperoxides. The cost of the electricity for the electroreduction was at least 30 times lower as compared with sodium borohydride consumption. 9‐Hydroxynonanoic acid was then transformed to alkyl 9‐acetoxynonanoates 3a–3d, for which 1H nuclear magnetic reasonance, mass, and infrared spectra are given. Esterification of the hydroxy acid 1 with boric acid and pyrolysis of the resultant orthoborates produced 8‐nonenoic acid 4 in a 45% yield. Reaction of 4 with lower aliphatic alcohols in presence of Amberlyst 15 produced alkyl 8‐noneates 5a–5d along with some amounts of a cis/trans mixture of alkyl 7‐noneates.
Production and characterization of an extensive rapeseed protein hydrolysate
Authors: Vioque Javier , Sánchez‐Vioque Raul , Clemente Alfonso , Pedroche Justo , Bautista Juan , Millan Francisco
Published: May 2007

Rapeseed protein isolate has been used as starting material for the generation of an extensive protein hydrolysate. Protein hydrolysis was produced by using sequentially an endopeptidase (Alcalase) and an exopeptidase (Flavourzyme). The final hydrolysate has a 60% degree of hydrolysis and was completely soluble between pH values 2.5 and 7. Molecular weight profile of the protein hydrolysate was characterized by gel filtration chromatography. A reduction in protein size was observed during the hydrolysis process with accumulation of small peptides and free amino acids after Flavourzyme digestion. Amino acid composition of fractions with different molecular weights of the final hydrolysate was analyzed. Some of these fractions, enriched or poor in certain amino acids, could be used for supplementation or treatment of determined clinical syndromes.
γ‐Linolenic acid‐rich triacylglycerols derived from borage oil via lipase‐catalyzed reactions
Authors: Huang Fang‐Cheng , Ju Yi‐Hsu , Chiang Jen‐Chung
Published: May 2007

γ‐Linolenic acid (GLA), a precursor of arachidonic acid, possesses physiological functions of modulating immune and inflammatory response. Highly purified GLA is desired both as a medicine and as an ingredient of cosmetics. In this work, urea fractionation and lipase‐catalyzed reactions were employed for the enrichment of GLA in borage oil. GLA content in free fatty acids from saponified borage oil can be increased from 23.6 to 94% by the method of urea fractionation. Partial hydrolysis of borage oil catalyzed by immobilized Candida rugosa lipase raises GLA content in the unhydrolyzed acylglycerols from 23.6 to 52.1%. The IM‐60 catalyzed acidolysis reaction between the GLA‐rich free fatty acid and the unhydrolyzed acylglycerols increases the GLA content in the acylglycerols from 52.1 to 75%. The acylglycerols in the reaction product contains ca. 90% triacylglycerol. The effects of temperature, water content, substrate weight ratio, and organic solvents on the GLA content in the acylglycerols were examined.
Enzymatic synthesis of symmetrical 1,3‐diacylglycerols by direct esterification of glycerol in solvent‐free system
Authors: Rosu Roxana , Yasui Mamoru , Iwasaki Yugo , Yamane Tsuneo
Published: May 2007

1,3‐Diacylglycerols were synthesized by direct esterification of glycerol with free fatty acids in a solvent‐free system. Free fatty acids with relatively low melting points (<45°C) such as unsaturated and medium‐chain saturated fatty acids were used. With stoichiometric ratios of the reactants and water removal by evaporation at 3 mm Hg vacuum applied at 1 h and thereafter, the maximal 1,3‐diacylglycerol content in the reaction mixture was: 84.6% for 1,3‐dicaprylin, 84.4% for 1,3‐dicaprin, 74.3% for 1,3‐dilinolein, 71.7% for 1,3‐dieicosapentaenoin, 67.4% for 1,3‐dilaurin, and 61.1% for 1,3‐diolein. Some of the system's parameters (temperature, water removal, and molar ratio of the reactants) were optimized for the production of 1,3‐dicaprylin, and the maximal yield reached 98%. The product was used for the chemical synthesis of 1,3‐dicapryloyl‐2‐eicosapentaenoylglycerol. The yield after purification was 42%, and the purity of the triacylglycerol was 98% (both 1,3‐dicapryloyl‐2‐eicosapentaenoylglycerol and 1,2‐dicapryloyl‐3‐eicosapentaenoylglycerol included) by gas chromatographic analysis, of which 90% was the desired structured triacylglycerol (1,3‐dicapryloyl‐2‐eicosapentaenoylglycerol) as determined by silver ion high‐performance liquid chromatographic analysis.
Kinetics of enzymatic synthesis of isopropylidene glycerol esters by goat pregastric lipase
Authors: Lai Douglas T. , Hattori Norikatsu , O’Connor Charmian J.
Published: May 2007

The goat pregastric lipase‐catalyzed esterification of isopropylidene glycerol with caproic acid, to form isopropylidene glycerol caproate, followed a ping pong bi bi mechanism incorporating an acyl‐enzyme intermediate. The maximum rate was estimated to be 96 µmol min−1 mg−1 in isooctane at 35°C, and the Michaelis‐Menten constants for isopropylidene glycerol and caproic acid were 0.23 and 0.32 M, respectively. The catalyzed rate also correlated well with the partition coefficient of caproic acid between the organic and aqueous phases. The results suggest that the desolvation energy of the substrate from the bulk medium to the active site of the enzyme dominates the reaction rate for the enzyme‐catalyzed reaction in organic media.
Two‐dimensional surface properties of 2‐methoxy ethyl oleate at the air/water interface
Authors: Baskar Geetha , Venkatesan S. , Dhathathreyan Aruna , Mandal A. B.
Published: May 2007

Methoxy ethyl oleate, a nonionic surfactant, has been investigated at the air/water interface for various surface properties by employing the Langmuir film balance technique. The ester forms an expanded isotherm at the air/water interface. The minimum area of packing (A0), initial area of increase of surface pressure (Ai), collapse pressure (πc), and area/molecule at collapse pressure (Ac) have been estimated from the isotherm curve. The higher compressibility coefficient (K) suggests that the ester forms a more expanded liquid film than the parent oleic acid. Besides, the ester film is fairly stable as suggested by only about 30% loss in area over a period of 20 min. The relaxation rates of the ester film at different surface pressures of 10, 15, and 20 mN·m−1 have been estimated from changes in the surface area/molecule with time. Interestingly, the surface area (54.2 Å2/molecule) that corresponds to a minimized structure projected for the ester, calculated theoretically, agrees reasonably well with the experimental value (57.2 Å2/molecule).
Practical nuclear magnetic resonance analysis of liquid oil in oilseeds: I factors affecting peak width
Authors: Reaney Martin J. T. , Tyler Nancy J. , Brown Keith
Published: May 2007

If proton nuclear magnetic resonance (NMR) spectra of single seeds can be improved, a rapid, low‐cost method of screening seeds for oil composition could be developed for use as a selection tool in plant breeding. NMR spectroscopy was performed on single seeds of borage, flax, and canola to evaluate methods for improving spectra quality (narrowing peak widths and increasing signal‐to‐noise ratio) to a degree necessary to measure differences among seeds in a breeding program. Immersion of seeds in a variety of solvents, including deuterated chloroform, deuterated acetone, deuterated dimethyl sulfoxide (DMSO) and completely fluorinated hydrocarbons (FC‐77), narrowed peaks obtained from seeds when compared with spectra from seeds analyzed in the absence of a solvent. Deuterated chloroform and FC‐77 were free of interfering solvent proton peaks while deuterated acetone and deuterated DMSO contributed interfering peaks. The spectra of dehulled seeds had narrower peak widths than did seeds with hulls. Treatments that decreased seed oil viscosity failed to substantially narrow spectra peak widths of seeds. High magnetic field strength did not improve the spectral quality of seeds, as peak widths increased with field strength. Conversely, low field strength limited resolution of oil spectra. Although the 300 MHz spectrum of vegetable oil had greater resolution (narrower peaks) than the 60 MHz spectrum, spectra of seeds produced at 60 MHz had superior resolution to 300 MHz spectra.
Rapid analysis of oxidized cholesterol derivatives by high‐performance liquid chromatography combined with diode‐array ultraviolet and evaporative laser light‐scattering detection
Authors: Osada Kyoichi , Ravandi Amir , Kuksis Arnis
Published: May 2007

Extensive evidence of the deleterious biological effects of oxidized 5‐cholesten‐3β‐ol (cholesterol) derivatives has led to great interest in their detection. We observed that known oxidized cholesterol derivatives can be rapidly quantitated by combining reversed‐phase high‐performance liquid chromatography (HPLC) with ultraviolet (UV) absorption and evaporative laser light‐scattering (ELSD) detection. Using a 20 × 0.46 cm C18 HPLC column and methanol/acetonitrile (60:40, vol/vol) as the mobile phase at 1.0 mL/min, 10 species of oxidized cholesterol derivative were measured by UV (205, 234, and 280 nm) while 5‐cholestan‐5α,6α‐epoxy‐3β‐ol (5α‐epoxycholesterol), 5‐cholestan‐5β,6β‐epoxy‐3β‐ol (5β‐epoxycholesterol), and 5‐cholestan‐3β,5α,6β‐triol (cholestanetriol) were detected by only ELSD. The minimal limits of detection ranged from 100 to 500 ng depending on sterol and detector. The response was linear in the range 0–1000 or 0–2000 ng depending on detector. These oxidized cholesterol derivatives were also identified by HPLC/mass spectrometry analysis combined with UV detector. Heated tallow contained cholestanetriol, 5‐cholesten‐3β,7α‐diol (7α‐hydroxycholesterol), 5‐cholesten‐3β,7β‐diol (7β‐hydroxycholesterol), 5‐cholesten‐3β‐ol‐7‐one (7‐ketocholesterol), 5α‐ and 5β‐epoxycholesterols under the developed analysis condition. Photooxidized cholesterol had cholestanetriol, 7α‐ and 7β‐hydroxycholesterols and 3,5‐cholestadien‐7‐one. On the other hand, 7α‐ and 7β‐hydroxycholesterols, 7‐ketocholesterol, 5α‐ and 5β‐epoxycholesterols and 3,5‐cholestadien‐7‐one were observed in copper‐oxidized low‐density lipoprotein. Thus, this developed HPLC analysis method could be applied to identification of oxidized cholesterol derivatives in food and biological specimen.
High‐performance liquid chromatography evaluation of phenols in olive fruit, virgin olive oil, vegetation waters, and pomace and 1D‐ and 2D‐nuclear magnetic resonance characterization
Authors: Servili Maurizio , Baldioli Maura , Selvaggini Roberto , Miniati Enrico , Macchioni Alceo , Montedoro Gianfrancesco
Published: May 2007

Phenolic compounds are the most important antioxidants of virgin olive oil. This paper reports on the application of solid phase extraction (SPE) in the separation of phenolic compounds from olive fruit, olive oil, and by‐products of the mechanical extraction of the oil and the complete spectroscopic characterization by nuclear magnetic resonance of demethyloleuropein and verbascoside extracted from olive fruit. SPE led to a higher recovery of phenolic compounds from olives than did liquid/liquid extraction. SPE also was used to separate phenolic compounds from pomaces and vegetation waters. Phenylacid and phenyl‐alcohol concentrations in extracts obtained from SPE and liquid/liquid extraction were not significantly different (P<0.05). The recovery of the dialdehydic form of elenolic acid linked to 3,4‐(dihydroxyphenyl)ethanol and an isomer of oleuropein aglycon, however, was low.
Enzymatic modification of triacylglycerols of high eicosapentaenoic and docosahexaenoic acids content to produce structured lipids
Authors: Jennings Brenda H. , Akoh Casimir C.
Published: May 2007

Immobilized lipase, IM60, from Rhizomucor miehei was used as a biocatalyst for the incorporation of capric acid (C10:0) into fish oil originally containing 40.9 mol% eicosapentaenoic (20:5n‐3) and 33.0 mol% docosahexaenoic (22:6n‐3) acid. Acidolysis was performed with and without organic solvent. Pancreatic lipase‐catalyzed sn‐2 positional analysis was performed after enzymatic modification. Tocopherol analysis was performed before and after enzymatic modification. Products were analyzed by gas‐liquid chromatography. After a 24‐h incubation in hexane, there was an average of 43.0±1.6 mol% incorporation of C10:0 into fish oil, while 20:5 and 22:6 decreased to 27.8±2.2 and 23.5±1.3 mol%, respectively. The solvent‐free reaction produced an average of 31.8±8.5 mol% C10:0 incorporation, while 20:5 and 22:6 decreased to 33.2±3.3 and 28.3±3.9 mol%, respectively. The effect of incubation time, substrate molar ratio, enzyme load, and added water were also studied. In general, as the enzyme load, molar ratio, and incubation time increased, mol% C10:0 incorporation also increased. The optimal mol% C10:0 incorporation was 41.2% at 48 h for the reaction in hexane and 46.4% at 72 h for the solvent‐free reaction. The highest C10:0 incorporation (65.4 mol%) occurred at a molar ratio of 1:8 (fish oil triacylglycerols/capric acid) in hexane. For the solvent‐free reaction, the optimal mol% C10:0 incorporation (56.1 mol%) occurred at a molar ratio of 1:6. An enzyme load of 10% gave the highest mol% C10:0 incorporation (41.4 mol%) in hexane; the highest incorporation (38.3 mol%) for the solvent‐free reaction occurred at 15% enzyme load. Mol% incorporation of C10:0 declined with increasing amounts of added water. The optimal mol% C10:0 incorporation occurred at 1% added water (47.9 mol%) for the reaction in hexane, and at zero added water for the solvent‐free reaction (21.8 mol%). Fish oil containing capric acid was successfully produced and may be nutritionally more beneficial than unmodified oil.
Enzymatic synthesis of l‐menthyl esters in organic solvent‐free system
Authors: Shimada Yuji , Hirota Yoshinori , Baba Takashi , Kato Shinichiro , Sugihara Akio , Moriyama Shigeru , Tominaga Yoshio , Terai Tadamasa
Published: May 2007

l‐Menthol has been widely used as a food additive and an ingredient of cosmetics, and it is esterified to moderate the strong flavor. We attempted esterification of l‐menthol with long‐chain unsaturated fatty acid in an organic solvent‐free enzymatic system. Commercially available lipases were screened, and Candida rugosa lipase was selected as a catalyst. Several factors affecting the esterification were investigated, and the reaction conditions were determined as follows: A reaction mixture of l‐menthol/fatty acid (1:3, mol/mol), 30% water, and 700 units of the lipase per gram of reaction mixture was incubated at 30°C with stirring. After 24 h under these conditions, the esterification extents of l‐menthol with oleic, linoleic, and α‐linolenic acids reached 96, 88, and 95%, respectively. The structure of the esterified product was confirmed by mass, infrared, and nuclear magnetic resonance spectroscopies. Bacause Candida lipase acted strongly on l‐menthol and very weakly on d‐menthol, dl‐menthol was esterified with oleic acid under the same conditions. The reaction showed high enantioselectivity; the enantiomeric ratio (E) was 31, and enantiomeric excess (ee) of l‐menthyl oleate reached 88% after 32 h.
Preparation of phospholipids highly enriched with n‐3 polyunsaturated fatty acids by lipase
Authors: Haraldsson Gudmundur G. , Thorarensen Atli
Published: May 2007

The immobilized 1,3‐regiospecific Rhizomucor miehei lipase (Lipozyme™) was employed to catalyze the transesterification reaction (acidolysis) of 1,2‐diacyl‐sn‐glycero‐3‐phosphatidylcholine with n‐3 polyunsaturated fatty acids under nonaqueous solvent‐free conditions. With a concentrate of 55% eicosapentaenoic acid (EPA) and 30% docosahexaenoic acid (DHA) and pure phosphatidylcholine from egg yolk, phospholipids of 32% EPA and 16% DHA content were obtained, presumably as a mixture of phosphatidylcholine and lysophosphatidylcholine. 31P nuclear magnetic resonance (NMR) analysis turned out to be a valuable technique to study the details of the reactions involved. It revealed that when 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphatidylcholine was transesterified with 98% pure EPA, a substantial amount of hydrolysis side reaction took place (39%), leading to a product mixture of 39% phosphatidylcholine, 44% lysophosphatidylcholine, and 17% sn‐glycerol‐3‐phosphatidylcholine. The lysophosphatidylcholine constituent comprised 70% EPA, whereas the phosphatidylcholine component contained 58% EPA. The 31P NMR technique provided valid information about the mechanism of the reaction. It became evident that a high dosage of lipase containing 5% water afforded optimal conditions for the optimal extent of EPA incorporation into the phospholipids, under which the extent of hydrolysis side reaction remained relatively high.
All (S) stereoconfiguration of 7,10‐dihydroxy‐8(E)‐octadecenoic acid from bioconversion of oleic acid by Pseudomonas aeruginosa
Authors: Gardner Harold W. , Hou Ching T.
Published: May 2007

A previously established method was utilized to determine the stereoconfiguration of 7,10‐dihydroxy‐8(E)‐octadecenoic acid (DHOE) from bioconversion of oleic acid by Pseudomonas aeruginosa NRRL strain B‐18602 (PR3). The method involved formation of the (−)‐menthoxycarbonyl (MCO) derivative of the two hydroxyls, oxidative cleavage of the double bond, and gas chromatography (GC) analysis of the two methyl‐esterified diastereomeric fragments, methyl 2‐MCO‐decanoate and dimethyl 2‐MCO‐octanedioate. As described by previous workers, the 2(S)‐MCO derivatives elute at earlier times by GC than the 2(R)‐MCO derivatives. By comparing the GC analysis of the 2‐MCO derivatives obtained from DHOE with that obtained from a partially racemized sample, DHOE was determined to be 7(S),10(S)‐dihydroxy‐8(E)‐octadecenoic acid.
Partial purification and characterization of acylester hydrolase from Lupinus mutabilis
Authors: Anduaga Walter , Svensson Ingemar , Adlercreutz Patrick , Mattiasson Bo
Published: May 2007

An alkaline acylester hydrolase was partially purified from germinated seeds of Lupinus mutabilis. Hydrolytic activity was absent in the crude extract of ungerminated lupine seed, but it increased and peaked at the fourth day in the germinating seedling. The purification scheme involved homogenization, centrifugation, acetone precipitation, anion exchange chromatography, pH precipitation, and hydrophobic interaction chromatography. The acylester hydrolase was purified 126‐fold, and the overall activity yield was 10%. The molecular weight estimated by sodium dodecylsulfate‐polyacrylamide gel electrophoresis was 60 kDa. The enzyme had an isoelectric point of 6.2 and showed maximal activity at pH 8.0. The enzyme showed good stability between pH 5.0 and 9.0. In the pH range 7.0–7.5, enzyme precipitation was observed. The enzyme was stable from 0 to 25°C for 5 h and at 45°C lost 50% of its activity in the same period of time. At higher temperatures, the enzyme showed low thermal stability. However, the highest initial activity was found to be at 45°C. Nonionic surfactants and cholic acid enhanced the activity of the enzyme. The activity was reduced by the addition of toluene and isooctane and increased by the addition of diethyl ether, acetonitrile, methanol, and pyridine. The activity was reduced by 37% in the presence of 1 mM Cu2+ ions. The enzyme‐hydrolyzed triolein showing no positional specificity.
Lipoxygenase activity in olive (Olea europaea) fruit
Authors: Salas Joaquín J. , Willams Mark , Harwood John L. , Sánchez Juan
Published: May 2007

The present work was designed to characterize lipoxygenase activity in olive fruit pulp, in order to determine its significance in the biosynthesis of virgin olive oil aroma. Lipoxygenase activity has been detected in particulate fractions of enzyme extracts from olive pulp subjected to differential centrifugation. The activity in different membrane fractions showed similar properties, with optimal pH in the range of 5.0–5.5 and a clear specificity for linolenic acid, which was oxidized at a rate double that of linoleic acid under the same reaction conditions. The enzyme preparations displayed very low activity with dilinoleoyl phosphatidylcholine, suggesting that olive lipoxygenase acts on nonesterified fatty acids. The enzyme showed regiospecificity for the Δ‐13‐position of both linoleic and linolenic acid, yielding 75–90% of Δ‐13‐fatty acid hydroperoxides. Olives showed the highest lipoxygenase activity about 15 wk after anthesis, with a steady decrease during the developmental and ripening periods. Olive lipoxygenase displayed properties that support its involvement in the biogenesis of six‐carbon volatile aldehydes, which are major constituents of the aroma of virgin olive oil, during the process of oil extraction.
Thermoxidative stability of triacylglycerols from mutant sunflower seeds
Authors: Márquez‐Ruiz Gloria , Garcés Rafael , León‐Camacho Manuel , Mancha Manuel
Published: May 2007

Thermoxidative stability was evaluated in triaclyglycerols (TAG) from the oils of the mutant sunflower lines CAS‐3, CAS‐4, and CAS‐8 (with a high percentage of stearic acid), CAS‐5 (with a high percentage of palmitic acid), all from standard highlinoleic genetic backgrounds, and the mutant sunflower line CAS‐12 (with a high percentage of palmitic acid), from a high‐oleic genetic background. These oils contained unusually high contents of TAG molecular species with one or two saturated fatty acids at the sn‐1,3 positions. Purified total TAG devoid of tocopherols were subjected to controlled thermoxidative treatment at 180°C. Polymerized TAG were determined at 2‐h intervals for 10 h. After this time, total polar compounds, oxidized TAG monomers, TAG dimers, and TAG oligomers were determined. TAG from highly saturated sunflower oils with levels of linoleic acid similar to those found in conventional sunflower oils (40–50%) showed enhanced thermal stability. In these TAG, the amount of polar compounds formed during the thermoxidative treatment was similar to that formed in the high oleic acid line. Excellent results were obtained for the TAG of the CAS‐12 oil, which had the highest thermal stability, producing half the amount of polar compounds as the conventional line and less than two‐thirds that of the high‐oleic line.
Trans‐free margarine from highly saturated soybean oil
Authors: Kok Li Lee , Fehr Walter R. , Hammond Earl G. , White Pamela J.
Published: May 2007

Highly saturated (HS) soybean oil (SBO), which contained 23.3% palmitic acid (C16:0) and 20.0% stearic acid (C18:0), was interesterified at 70°C in preparation for the processing of a trans‐free margarine. High‐performance liquid chromatography analysis of the triacylglycerides and analysis of the sn‐2 fatty acid composition showed no further change after 10 min of interesterification. The interesterified HS SBO had a slip melting point of 34.5°C, compared with 9.5°C in the non‐interesterified HS SBO, and increased melting and crystallization temperatures were found using differential scanning calorimetry. Analysis of solid‐fat content by nuclear magnetic resonance revealed the presence of only a small amount of solids above 33°C. A 50:50 blend of interesterified HS SBO and SBO with a typical fatty acid composition was used to make the margarine. Compared to commercial soft‐tub margarine, the maximal peak force on the texture analyzer of this blended margarine was about 2.3 times greater, the hardness about 2.6 times greater, and adhesiveness about 1.5 times greater. There were small but statistically significant differences (α=0.05) in the sensory properties of spreadability, graininess, and waxiness between the commercial and blended margarines at 4.5°C and, except for graininess, at 11.5°C. These very small differences suggest a potential use for HS SBO in margarine products.
Hydrocarbons detected in irradiated shell eggs during storage
Authors: Hwang Keum Taek
Published: May 2007

Hydrocarbons produced by γ‐radiation of shell eggs were analyzed to determine how irradiation affects their production. Shell eggs were nonirradiated or irradiated at 0.5, 1, and 3 kGy and the stored at 5°C for 8 wk or at 30°C for 10 d. Hydrocarbons were determined by a sequential procedure of lipid extraction by hexane, Florisil column chromatography, and gas chromatography. Hydrocarbons C15:0, C14:1, C17:0, C16:1, C17:1, C16:2, C17:2, and C16:3 were detected in shell eggs irradiated at 0.5 kGy or higher, but not in nonirradiated ones except C15:0 and C17:0. Storage of nonirradiated or irradiated eggs had little effect on detection levels of hydrocarbons. The detection levels in all the samples irradiated at 1 and 3 kGy were in the order of C16:2+C17:1, C15:0+C14:1, C17:2+C16:3, and C17:0+C16:1 from the highest to the lowest.
Physical and mechanical properties of soy protein‐based plastic foams
Authors: Park Sang K. , Hettiarachchy N. S.
Published: May 2007

Flexible plastic foams using soy protein isolate (SPI), soy protein concentrate (SPC), and defatted soy flour (DFS) were produced by interacting proteins with glycerol‐propylene oxide polyether triol (polyol), surfactant, triethanolamine (crosslinking agents), tertiary amine (catalyst), and water (blowing agent). The density, compressive stress, resilience, and dimensional stability of foams with SPI, SPC, and DFS increased as the initial concentration of soy protein increased. The foam density increased with increasing weight percentage of SPI, SPC, and DFS. The resilience values of SPI containing foam increased with the increasing addition of SPI up to a maximum 30% SPI addition. An increase in SPI up to 20% caused an increase in the compressive stress (225 kPa) in comparison to control polyurethane foam (187 kPa). The control foam and foam containing 20% DFS had a similar load‐deformation relationship. The foam containing 20% SPI and SPC also exhibited a similar shape, but with a higher compressive stress. The compressive stress of all foams was steeply increased after 55% strain, since the foams completely collapsed upon compression.
Studies of thermal polymerization of vegetable oils with a differential scanning calorimeter
Authors: Wang Chaohua , Erhan Sevim
Published: May 2007

Vegetable oils are often thermally polymerized to provide a vehicle for printing inks and paints. The formations of isomerization, and the intra‐ and intermolecular bonds involved in the thermal process are crucial in designing a product with the appropriate characteristics. It was found, with a differential scanning calorimeter, that the thermal polymerization of various vegetable oils could be activated at lower temperatures under a dry‐air purge and/or in the presence of metallic catalysts. The Diels‐Alder reaction and the formation of intermolecular bonds in alkali‐refined soybean oil under a dry‐air purge could be activated at 99 and 161°C in the presence of metallic catalysts, compared with 231 and over 300°C in the absence of metallic catalysts, respectively. The energies needed to activate the Diels‐Alder reaction and to form intermolecular bonds were calculated, and is in good agreement with available data. The hardness test of baked vegetable‐oil systems was also implemented to qualitatively determine the degree of cross‐linking.