bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphatidylcholine as the choline donor in sphingomyelin synthesis
Authors: Eppler C. Mark , Malewicz Barbara , Jenkin Howard M. , Baumann Wolfgang J.
Published: November 2006

Sphingomyelin synthesis was studied in cultured Novikoff rat hepatoma cells by following transfer of [14C]choline label into sphingomyelin (SPH). The study was facilitated by the fact that prelabeling of the cells with [Methyl‐14C]choline resulted in rapid accumulation of essentially all the label (≈95%) in phosphatidylcholine (PC). The redistribution of PC label during a 15‐hr chase was dependent upon the extracellular choline concentration. Under conditions of free choline diffusion (500 μM choline), loss of lable from PC was most pronounced, and the percentage of total radioactivity that became trapped in the extracellular water‐soluble choline pool was an order of magnitude greater than in low choline medium (27 μM choline). Despite the significant loss of water‐soluble label from the cells in high choline medium, SPH labeling proceeded at essentially the same rate at either choline concentration. During the label chase in 500 μM choline, the specific radioactivity of PC decreased, but the specific radioactivity of SPH continued to increase for 9–12 hr until it reached the specific radioactivity of PC. In the presence of 300 μM neophenoxine (NPO), transfer of label from PC into SPH was stimulated. NPO also decreased the specific radioactivity of PC to about the same extent as that of SPH was increased. Because transfer of choline label from PC to SPH was not affected by loss or dilution of water‐soluble precursors, and because the specific radioactivity of PC and SPH, in the absence or presence of NPO, responded in a characteristic precursor product fashion, we conclude that sphingomyelin synthesis in Novikoff cells circumvents the water‐soluble choline pool and that phosphatidylcholine serves as the immediate choline source. All our data support the phosphatidylcholine:ceramide cholinephosphotransferase pathway of sphingomyelin synthesis.
Characteristics of phospholipids in human lung carcinoma
Authors: Nakamura Mitsushige , Onodera Tsugutami , Akino Toyoaki
Published: November 2006

Human lung carcinoma tissues with histological types of adenocarcinoma, squamous cell and small cell carcinoma were investigated for phospholipids. There were marked differences in the phospholipids between these lung carcinoma and normal lung tissue. A marked decrease in saturated phosphatidylcholine (PC), predominantly the dipalmitoyl species, was noted in the carcinoma, although they still contained 17–20% of the saturated classes. The lung carcinoma contained less phosphatidylglycerol (PG) and lyso‐bis‐phosphatidic acid and more cardiolipin and phosphatidylinositol (PI) than the normal lung tissue. These alterations observed in the lung carcinoma apppeared to show that they lose the characteristic feature of phospholipids in the lung tissue. The differences in the lipid composition among different cell types of lung carcinoma were also noted. The squamous cell and small cell carcinoma contained more triacylglycerol and relatively higher dienes I (monoenoic‐monoenoic) and lower dienes II (saturated‐dienoic) of PG, respectively, as compared to adenocarcinoma.
Comparative studies on composition of cardiac phospholipids in rats fed different vegetable oils
Authors: Kramer J. K. G.
Published: November 2006

Male Sprague‐Dawley rats were fed diets for 1 or 16 weeks, containing 20% by weight vegetable oils differing widely in their oleic, linoleic and linolenic acid content. No significant changes were observed in the level of the cardiac lipid classes. The fatty acid composition of the 2 major phospholipids, phosphatidylcholine and phosphatidylethanolamine, showed a remarkable similarity between diets in the concentration of total saturated, C22 polyunsaturated and arachidonic acids. Monounsaturated acids were incorporated depending on their dietary concentration, but the increases were moderate. Dietary linolenic acid rapidly substituted C22 polyunsaturated fatty acids of the linoleic acid family (n−6) with those from the linolenic acid family (n−3). The results suggest that dietary linolenic acid of less than 15% does not inhibit the conversion of linoleic to arachidonic acid but the subsequent conversion of arachidonic acid to the C22 polyunsaturates was greatly reduced. Significant amounts of dietary monounsaturated fatty acids were incorporated into cardiac cardiolipin accompanied by increases in polyunsaturated fatty acids, apparently to maintain an average of 2 double bonds/molecule. The cardiac sphingomyelins also accumulated monounsaturated fatty acids depending on the dietary concentration. It is quite evident from the results of this study that the incorporation of oleic acid and the substitution of linolenic for linoleic acid‐derived C22 polyunsaturated fatty acids into cardiac phospholipids was related to the dietary concentration of these fatty acids and was not peculiar to any specific oil. Even though it is impossible to estimate the effect of such changes in cardiac phospholipids on membrane structure and function, results are discussed which suggest that the resultant membrane in the Sprague‐Dawley male rat is more fragile, leading to greater cellular breakdown and focal necrosis.
Dinosterol in model membranes: Fluorescence polarization studies
Authors: Harel Zvi , Djerassi Carl
Published: November 2006

The interaction between the phospholipids ofCrypthecodinium cohnii, a heterotropic marine dinoflagellate, and its major sterol dinosterol was studied using a fluorescence polarization technique. Compared to cholesterol, dinosterol is less soluble in model membranes and as effective in increasing the microviscosity. These results indicate that the unique side chain of dinosterol does not play a special role in terms of complementary interaction with the phospholipids of this organism.
Selective reactions in the analysis and characterization of steroids by gas chromatography‐mass spectrometry
Authors: Brooks C. J. W. , Cole W. J. , McIntyre H. B. , Smith A. G.
Published: November 2006

Gas chromatography‐mass spectrometry (GC‐MS) is a technique especially suitable for the analysis and characterization of steroids, and its power has been extensively demonstrated. The efficacy of GC‐MS is limited, nevertheless, by the fact that steroid mixtures—whether of natural origin only, or augmented by synthetic analogs—often contain similar components that are poorly distinguished. The fortuitous overlap of gas chromatographic peaks from disparate compounds also impairs the definition of retention data. Controlled modification of the sample by means of selective reactions is therefore a valuable adjunct to the application of GC‐MS. Two examples are discussed: (a) the enzyme cholesterol oxidase, isolated from various microorganisms, catalyzes the oxidation of many 3β‐hydroxy‐5‐enes (with concomitant isomerization) to 4‐en‐3‐ones; 3β‐hydroxy‐5α‐steroids are also oxidized to the corresponding 3‐ones, but other steroids (3α‐hydroxy‐ or 5β‐isomers, etc.) are unaffected. The mild conditions required (pH 7, 30 C) are advantageous for the analysis of sensitive steroids, and the retention index increments, as well as the mass spectra of the ketones, are characteristic. The enzyme accepts as substrates a wide range of 3β‐hydroxysteroids, tolerating oxygenation in ring B and even catalyzing the oxidation of 2‐oxacholesterol to the expected lactone; and (b) steroids possessing 1,2‐diol or 1,3‐diol groupings include estriols, 2‐hydroxyestrone, 20,22‐dihydroxycholesterols, ecdysones, brassinolide and many corticosteroids. The selective formation of cyclic derivatives can provide several analytically useful features, such as convenient retention times, moderate mass increments (24 amu for a methaneboronate), distinctive mass spectra and usually abundant molecular ions. These are exemplified for 5‐pregnene‐3β‐20,21‐triols and for 20,22‐dihydroxycholesterol as well as its enzymic oxidation product.
Abnormal suppression of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase activity in cultured human fibroblasts by hypertriglyceridemic very low density lipoprotein subclasses
Authors: Gianturco Sandra H. , Packard Christopher J. , Shepherd James , Smith Louis C. , Catapano Alberico L. , Sybers Harley D. , Gotto Antonio M.
Published: November 2006

Our previous studies showed that hypertriglyceridemic very low density lipoproteins (HTG VLDL) are functionally abnormal. HTG VLDL, but not normal VLDL, suppress HMG‐CoA reductase in cultured normal human fibroblasts. To determine if the suppression by HTG VLDL resulted from a subpopulation of smaller suppressive particles, more homogeneous subclasses of VLDL‐VLDL1 (Sf 100–400), VLDL2 (Sf 60–100), and VLDL3 (Sf 20–60) were obtained from the d<1.006 (g°ml−1) fraction of normal and hypertriglyceridemic plasma by flotation through a discontinuous salt gradient and tested for suppression in normal human fibroblasts. VLDL1 and VLDL2 from each of the 12 normolipemic subjects tested failed to suppress HMG‐CoA reductase activity in normal fibroblasts. Eleven out of 12 preparations of normal VLDL3 suppressed HMG‐CoA reductase, but only one‐third as effectively as LDL. By contrast, the VLDL1, VLDL2 and VLDL3 from 15 out of 17 hypertriglyceridemic patients (hyperlipoproteinemia Types IIb, III, IV and V) were highly effective in suppression, with half‐maximal suppression at 0.1–2.0 μg VLDL protein/ml. The VLDL abnormality is apparently associated with hypertriglyceridemia and not hypercholesterolemia, since VLDL from a homozygous familial hypercholesterolemia patient with a Type IIa pattern did not suppress whereas each of the VLDL subclasses from a Type IIb patient suppressed. Suppression by HTG VLDL in normal cells is apparently a consequence of interaction of the protein portion of the VLDL with the specific LDL cell surface receptor since HTG VLDL1 treated with 0.1 M 1,2‐cyclohexanedione to block arginyl residues failed to suppress the enzyme. Moreover, hypertriglyceridemic Sf 60–400 VLDL failed to suppress HMG‐CoA reductase activity in LDL receptor‐negative fibroblasts. There were no consistent major compositional differences between comparable normal and hypertriglyceridemic VLDL subclasses which could account for differences in suppression. All VLDL subclasses from Type III subjects were enriched in cholesteryl esters and depleted in triglyceride, relative to the corresponding normal VLDL subclasses. However, Type IV and Type V VLDL subclasses were normal in this repect. We conclude from these studies that small particle diameter is not required for suppression, since HTG VLDL1 and VLDL2 which contained few, if any, small particles were effective in suppression.
Formation of 12‐[18O]Oxo‐cis‐10,cis‐15‐phytodienoic acid from 13‐[18O]hydroperoxylinolenic acid by hydroperoxide cyclase
Authors: Vick Brady A. , Feng Paul , Zimmerman Don C.
Published: November 2006

13‐[18O] Hydroperoxylinolenic acid was permitted to react with an extract of flaxseed acetone powder containing hydroperoxide cyclase activity. The resulting product, 12‐oxo‐cis‐10,cis‐15‐phytodienoic acid (12‐oxo‐PDA), contained18O in the carbonyl oxygen at carbon 12, suggesting that an epoxide was an intermediate in the hyderoperoxide cyclase reaction. A substrate specificity study showed that acis double bond β,γ to the conjugated hydroperoxide group was essential for the substrate to be converted to a cyclic product by hydroperoxide cyclase.
A simple chromatographic method for purification of egg lecithin
Authors: Riis Nielsen Jørn
Published: November 2006

Egg lecithin was purified from the CdCl2‐lecithin complex by column chromatography on Alumina. The yield from 5 eggs was 2.8 g. The purified lecithin had correct chemical values for pure lecithin and a fatty acid composition similar to lecithin prepared by other methods. The method probably can be adapted for purification of other lipids containing the phosphocholine moiety and for purification of synthetic lecithin.
Improved separation of phospholipids in thin layer chromatography
Authors: Touchstone Joseph C. , Chen John C. , Beaver Kathleen M.
Published: November 2006

The mobile phases described permit separation of the six major phospholipids of amniotic fluid in one dimension with either conventional or high performance thin layer chromatography. An example of this separation with an extract of amniotic fluid is given.
Sterol and fatty acid composition of the clam,Codakia orbicularis, with chemoautotrophic symbionts
Authors: Berg Carl J. , Krzynowek Judith , Alatalo Philip , Wiggin Kate
Published: November 2006

Codakia orbicularis may obtain nutrients from chemoautolithotrophic bacteria. The chemical composition of theC. orbicularis was investigated because of this unusual source of nutrition, and because it is a human food source in the Caribbean. The lipid fraction of these molluscs is discussed in detail. Polyunsaturated fatty acids account for only 11–15% of the total fatty acids, and non‐methylene interrupted dienes are present as high as 9.5%. Cholesterol represents about 45% of the total sterols present.
Tocopherol‐phospholipid liposomes: Maximum content and stability to serum proteins
Authors: Halks‐Miller Meredith , Guo Luke S. S. , Hamilton Robert L.
Published: November 2006

This study addresses two questions: 1) what is the maximum amount of tocopherol that can be contained in egg phosphatidylcholine liposomes, and 2) what is the stability of these vesicles in the presence of serum proteins? These liposomes, made with a French pressure cell, can contain no more than 33 mol % of tocopherol. Tocopherol changes liposomes in a manner similar to cholesterol, making them larger, less permeable to aqueous dyes and highly resistant to protein‐induced disruption. The suppression of protein‐induced disruption is more pronounced with tocopherol than with cholesterol, even at lower molar ratios. Thus, liposomes containing alpha tocopherol (15 to 30 mol%) may be useful for delivering physiological quantities of this vitamin to cells in culture or to tissues in vivo.
High performance liquid chromatographic separation of diacylglycerol acetates to quantitate disaturated species of lung phosphatidylcholine
Authors: Itoh Kiyoharu , Suzuki Akira , Kuroki Yoshio , Akino Toyoaki
Published: November 2006

A high‐performance liquid chromatographic (HPLC) separation of diacylglycerol acetates to quantitatite disaturated species of lung phosphatidylcholine (PC) was studied. The diacylglycerol acetates were applied on a reversed phase column, eluted by an isocratic solvent, acetonitrile/isopropanol/water (35:15:1, v/v/v) at a flow rate of 1 ml/min, and detected by differential refractometry (RI). This isocratic HPLC method was useful to separate disaturated species from the others of lung PC.

The quantitative analysis of the molecular species separated by HPLC was studied by RI detection. Chroamtograms obtained by RI detection and radioactivity determination of diacylglycerol [3H]acetates prepared by [3H]acetic anhydride were almost identical. The RI detector responsed in the same degree for different, authentic standards of diacylglycerol acetates. The detection limit with RI detection was about 30 nmoles. Molecular species of PCs from human lung and carcinoma tissues were analyzed by this HPLC method. The contents of disaturated species were very similar to those reported previously. These results indicate that RI detection is very useful in the nmole range for the quantitative analysis among the molecular species containing disaturated species.
Modification of epoxidized soybean oil for lubricant formulations with improved oxidative stability and low pour point
Authors: Hwang Hong‐Sik , Erhan Sevim Z.
Published: November 2006

To produce soybean oil‐based lubricants with good oxidative stability and low pour point, epoxidized soybean oil (SBO) was chemically modified. Epoxidized SBO was reacted with various alcohols in the presence of sulfuric acid as a catalyst to give a ring‐opened intermediate product. In this step, the epoxy group was transformed to the functional group of‐CH(OR1)CH(OH)‐(where the R1=methyl, 1‐butyl, 2‐butyl, 1‐hexyl, cyclohexyl, 2,2‐dimethyl‐1‐propyl, or 1‐decyl). The 1H nuclear magnetic resonance spectra of the products indicated that transesterification was accompanied by the ringopening reaction except when the bulky 2,2‐dimethyl‐1‐propanol was used. Acid anhydride was used to esterify the hydroxy groups in the ring‐opened product. This resulted in a fluid that is a lubricant candidate with the functional group of −CH(OR1)CH(OCOR2)−. Pour point studies of the resulting products showed that the pour points varied with the substituents, R1 and R2. Products with R1=CH3(CH2)5− and R2=CH3(CH2)2−, (CH3)2CH−, or CH3(CH2)4‐showed the lowest pour points (−39, −39, and −45°C, respectively) when 1% of pour point depressant was added. For the oxidative stability test, two products, in which R1, R2=CH3(CH2)5−, (CH3)2CH− and R1, R2=CH3(CH2)5−, CH3(CH2)4−, were chosen for a modified Penn State micro‐oxidation test. In the oxidative stability test, the products gave 69–71% of oxidative evaporation and 10–17% of tetrahydrofuran‐insoluble deposits in 3 h at 175°C. The amounts of deposits were much lower than those of soybean oil (96%) and epoxidized SBO (83%) and even less than those of most petroleum‐based lubricant basestocks (3–93%).
Characterization of dihydroxystearic acid from palm oleic acid
Authors: Awang R. , Ahmad S. , Kang Y. B. , Ismail R.
Published: November 2006

Dihydroxystearic acid (DHSA) was prepared from palm oleic acid and characterized by chromatographic and spectroscopic methods (gas chromatography, thin‐layer chromatography, Fourier transform infrared and nuclear magnetic resonance spectroscopy) as well as wet chemistry. The crude product has a melting point of 62°C, acid value of 179, saponification value of 178, and hydroxyl value of 196. The yield was about 90% based on unsaturation. The product obtained was found to contain DHSA, saturated fatty acids, and unknown products. DHSA is soluble in alcohol, and its solubility decreased by increasing the alcohol chain length. An irritancy test of DHSA indicated that purified DHSA is nonirritating.
Simultaneous determination of lipophilic aldehydes by high‐performance liquid chromatography in vegetable oil
Authors: Seppanen C. M. , Csallany A. Saari
Published: November 2006

A very sensitive high‐performance liquid chromatography (HPLC) method was developed for the simultaneous separation and measurement of nonpolar and polar lipophilic secondary lipid peroxidation products in vegetable oil. Seventeen nonpolar and 13 polar lipophilic aldehydes and related carbonyl compounds, derived from thermally oxidized soybean oil as 2,4‐dinitrophenyl hydrazones, were separated simultaneously by reversed‐phase HPLC. Detection limit for the individual compounds is 1 ng. Thirteen of the nonpolar carbonyl compounds were identified as: butanal, 2‐butanone, pentanal, 2‐pentanone, hexenal, hexanal, 2,4‐heptadienal, 2‐heptenal, octanal, 2‐nonenal, 2,4‐decadienal, decanal, and undecanal. Three of the polar carbonyl compounds were identified as: 4‐hydroxy‐2‐hexenal, 4‐hydroxy‐2‐octenal, and 4‐hydroxy‐2‐nonenal. The detection of the toxic 4‐hydroxy‐2‐nonenal, a major compound, and 4‐hydroxy‐2‐hexenal, a minor compound, in heated soybean oil is of particular importance because these toxic compounds have been shown to be absorbed from the diet.
Trans, saturated, and unsaturated fat in foods in the united states prior to mandatory trans‐fat labeling
Authors: Satchithanandam Subramaniam , Oles Carolyn J. , Spease Carol J. , Brandt Mary M. , Yurawecz Martin P. , Rader Jeanne I.
Published: November 2006

On July 11, 2003, the U.S. Food and Drug Administration published a final rule amending its food‐labeling regulations to require that trans FA be declared in the nutrition label of conventional foods and dietary supplements. The effective date of this final rule is January 1, 2006. This places some urgency on increasing the number and types of currently available foods for which there are trans‐fat data. Compositional databases on trans fat content of food are currently limited. The purpose of this study was to determine the trans‐fat content of a wide range of foods prior to the effective date of the new regulation. AOAC Official Method of Analysis 996.01 was modified for the analysis of trans fat in noncereal products. Food products for analysis were selected on the basis of market share and data from the USDA's 1994–1996 Continuing Survey of Food Intake by Individuals. Foods were purchased from local supermarkets, weighed, hydrolyzed, converted to FAME, and analyzed by GC. The results showed that trans fat (g/100 g fat) ranged from 0.0 to 48.8 in bread, cake, and related products; from 14.9 to 27.7 in margarines; from 7.7 to 35.3 in cookies and crackers; from 24.7 to 38.2 in frozen potatoes; from 0.0 to 17.1 in salty snacks; from 0.0 to 13.2 in vegetable oils and shortenings; from 0.0 to 2.2 in salad dressings and mayonnaises; and from 0.0 to 2.0 in dry breakfast cereals. Serving sizes for the foods included in this survey ranged from 12 to 161 g, and trans‐fat levels ranged from 0.0 to 7.2 g/serving. The significant differences in trans‐fat content in products within each food category are due to differences in the type of fats and oils used in the manufacturing processes.
Validation of a single‐isotope‐labeled cholesterol tracer approach for measuring human cholesterol absorption
Authors: Wang Yanwen , Vanstone Catherine A. , Parsons William D. , Jones Peter J. H.
Published: November 2006

Cholesterol absorption is frequently determined using the plasma dual stable‐isotope ratio method (PDSIRM). However, this method involves intravenous injection of stableisotope‐labeled cholesterol with simultaneous oral administration of differently labeled cholesterol, which results in high study costs and involves additional ethical considerations. The objective of the present study was to validate a simpler singleisotope method for determining cholesterol absorption against PDSIRM by using data from two previous studies. Enrichments of carbon‐13 (13C) and deuterium in red blood cells were analyzed by using differential isotope ratio MS. The area under the curve of 13C‐enrichment in the plasma free‐cholesterol pool was found to be significantly correlated with cholesterol absorption measured by using PDSIRM for study 1 (r=0.85, P<0.0001) and study 2 (r=0.81, P<0.0001). Average 13C‐enrichment correlated with the area under the curve of 13C‐enrichment in the plasma free cholesterol for both study 1 (r=0.98, P<0.0001) and study 2 (r=1.00, P<0.0001). Study 1 examined the efficacy and mechanisms of unesterified plant sterols and stanols on lipid profiles in hypercholesterolemic men and women, while study 2 investigated the effects of phytosterol vs. phytostanol esters on plasma lipid levels and cholesterol kinetics in hyperlipidemic men. Experimental approaches to determine cholesterol absorption were identical between the two studies. Consequently, in both studies, correlations (r=0.88, P<0.0001 for study 1, and r=0.82, P<0.0001 for study 2) were found between the average 13C‐enrichment of plasma free cholesterol and cholesterol absorption measured by PDSIRM. These results suggest that a single‐isotope‐labeled cholesterol tracer approach can be used as a reliable noninvasive method to replace PDSIRM for examining changes in cholesterol absorption.
Stability determination of soy lecithin‐based emulsions by Fourier transform infrared spectroscopy
Authors: Whittinghill J. M. , Norton J. , Proctor A.
Published: November 2006

The stability of soy lecithin‐stabilized emulsions was determined by Fourier transform infrared spectroscopy. Oilin‐water (o/w) emulsions were prepared with 6% (vol/vol) medium‐chain triglycerides (MCT), 94% (vol/vol) water, and 4% (wt/vol) Lecigran and Lecimulthin soy lecithin. There were little or no differences between the 4% Lecigran and 4% Lecimulthin emulsions for all vibrational regions studied (OH at 3348 cm−1, C=O at 1741 cm−1, PO and C−O−C at 1157 cm−1, and P−O−C at 1101 cm−1), but the control emulsion, without emulsifier, had increased vibrations as the emulsion separated. The weaker vibrations of the more stable emulsions were probably due to reduced molecular interaction at the interface. However, added magnesium or calcium chloride enhanced the vibration of these groups, probably by disrupting the lecithin interaction at the emulsion interface.
Phytosterol accumulation in canola, sunflower, and soybean oils: Effects of genetics, planting location, and temperature
Authors: Vlahakis Chris , Hazebroek Jan
Published: November 2006

To assess the potential of traditional selection breeding to develop varieties with increased phytosterol content, we determined concentrations of those sterols in canola, sunflower, and soybean seed oils produced from breeding lines of diverse genetic backgrounds. Seed oils were extracted and saponified, and the nonsaponifiable fractions were subjected to silylation. The major phytosterols brassicasterol, campesterol, stigmasterol and β‐sitosterol, were quantified by capillary gas chromatography with flame‐ionization detection. Canola contained approximately twice the amount of total phytosterols (4590–8070 μg g−1) as sunflower (2100–4540 μg g−1) or soybean (2340–4660 μg g−1) oils. Phytosterol composition varied among crops as expected, as well as within a crop. Both genetic background and planting location significantly affected total phytosterol concentrations. Soybean plants were maintained from flower initiation to seed maturity under three temperature regimes in growth chambers to determine the effect of temperature during this period on seed oil phytosterol levels. A 2.5‐fold variability in total phytosterol content was measured in these oils (3210–7920 μg g−1). Total phytosterol levels increased with higher temperatures. Composition also changed, with greater percent campesterol and lower percent stigmasterol and β‐sitosterol at higher temperatures. In these soybean oils, total phytosterol accumulation was correlated inversely with total tocopherol levels. Owing to the relatively limited variability in phytosterol levels in seed oils produced under field conditions, it is unlikely that a traditional breeding approach would lead to a dramatic increase in phytosterol content or modified phytosterol composition.
Rheology of vegetable oil analogs and triglycerides
Authors: Geller Daniel P. , Goodrum John W.
Published: November 2006

The rheological properties of two complex mixtures of short‐chain triglycerides were experimentally determined. Dynamic or absolute viscosities of the mixtures were measured for shear rates of 0.32 to 64.69 s−1 at temperatures between 25 and 80°C. The compositions of the mixtures were based on the oil of the plant species Cuphea viscosissima VS‐320, a natural source of short‐chain triglycerides. The dynamic viscosities of these mixtures were compared to those of a traditional vegetable oil (peanut oil) and diesel fuel. The results of this comparison were used to make estimates of the performance of such triglyceride mixtures as diesel fuel substitutes, since viscosity can be a key indicator of fuel performance for possible substitute diesel fuels. The crystallization temperatures of these two mixtures were also determined experimentally, and the effects of crystallization on fuel performance were projected. Additionally, the dynamic viscosities of pure triglycerides from C6∶0 to C18∶0 at 75°C were plotted vs. chain length. These viscosities were measured at high shear rates (>6 s−1) where dynamic viscosity is shear‐independent. An obvious trend in the relationship between triglyceride chain length and viscosity was observed. A second‐order regression was used to obtain an equation for this relationship. This equation was used as a model for composition dependence of viscosity. This model was applied to the viscosities of the triglyceride mixtures examined here. There was good agreement between the model and the actual, measured viscosity values determined in this study.
The specific gravity of biodiesel and its blends with diesel fuel
Authors: Tat Mustafa E. , Van Gerpen Jon H.
Published: November 2006

The specific gravities of biodiesel and 75, 50, and 20% blends with No. 1 and No. 2 diesel fuels were measured as a function of temperature from the onset of crystallization to 100°C. The results indicate that biodiesel and its blends demonstrate temperature‐dependent behavior that is qualitively similar to the diesel fuels. The temperature dependence of the specific gravity for biodiesel and its blends was compared with the ASTM D 1250‐80 procedure for the temperature correction of hydrocarbon fuels, and the procedure was found to provide accurate corrections. A blending equation was developed that allows the specific gravity of blends to be calculated from the specific gravities of the biodiesel and diesel fuels.
Synthesis of δ‐stearolactone from oleic acid
Authors: Cermak Steven C. , Isbell Terry A.
Published: November 2006

δ‐Stearolactone was prepared from oleic acid using concentrated sulfuric acid under various conditions in the presence of polar, nonparticipating solvents. δ‐Stearolactone was formed in as high as 15∶1 ratios over the thermodynamic product, ψ‐lactone, in the presence of methylene chloride, 100% wt/vol, at room temperature with two equivalents of sulfuric acid for 24 h. This procedure is applicable to other olefinic fatty acids such as estolides and fatty acid methyl esters. Temperature plays a role in the regioselectivity of the cyclization for δ‐lactone, as lower temperatures (20°C) gave higher σ/ψ ratios. At higher temperatures (50°C) in the presence of sulfuric acid and methylene chloride the yield of lactone was 75% but with a σ/ψ ratio of only 0.3∶1. Cyclization of oleic acid to lactone also occurred with other acids. Oleic acid underwent reaction with perchloric acid, one equivalent, in the absence of solvent at 50°C, which yielded σ‐lactone in a modest yield with a 3.1 σ/ψ ratio. The same temperature effect was observed with perchloric acid that was observed in the case of sulfiric acid. Because σ‐stearolactone is much more reactive than the corresponding fatty acid, fatty acid ester, or ψ‐lactone, we believe that it will be a useful synthon for many new industrial products including new biodegradable detergents.
Purification of polyunsaturated fatty acid esters from tuna oil with supercritical fluid chromatography
Authors: Alkio M. , Gonzalez C. , Jäntti M. , Aaltonen O.
Published: November 2006

The technical and economic feasibility of producing docosahexaenoic acid (DHA)‐ and eicosapentaenoic acid (EPA)‐ethyl ester concentrates from transesterified tuna oil using supercritical fluid chromatography (SFC) was studied. A systematic experimental procedure was used to find the optimal values for process parameters and the maximal production rate. DHA ester concentrates up to 95 wt% purity were obtained in one chromatographic step with SFC, using CO2 as the mobile phase at 65°C and 145 bar and octadecyl silane‐type reversed‐phase silica as the stationary phase. DHA ester, 0.85 g/(kg stationary phase · h) and 0.23 g EPA ester/(kg stationary phase · h) can be simutaneously produced at the respective purities of 90 and 50 wt%. The process for producing 1,000 kg DHA concentrate and 410 kg EPA concentrate per year requires 160 kg stationary phase and 2.6 tons/h carbon dioxide eluant recycle. The SFC operating cost is U.S. $550/kg DHA and EPA ethyl ester concentrate.
Characterization of lipoxygenase extracts from Penicillum sp.
Authors: Perraud Xavier , Kermasha Selim
Published: November 2006

Biomasses of Penicillium camemberti and P. roqueforti strains were grown and harvested after 10 d of incubation, a period that corresponded to the maximal dry weight of mycelium as well as to lipoxygenase (LOX) activity. Partially purified LOX extracts were obtained by ammonium sulfate precipitation of the crude enzymatic extracts that had been recovered from the biomasses. The partially purified LOX extracts exhibited a preferential specificity toward free fatty acids, including linoleic, linolenic, and arachidonic acids, rather than fatty acid acylglycerols, including mono‐, di‐, and trilinolein. The Km and Vmax values of LOX activity were investigated. Normal‐phase high‐performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry analyses showed that the LOX activity of the microbial extracts converted linoleic acid mainly into the corresponding 9‐ and 13‐hydroperoxides (HPOD). However, the production of a significant proportion of 10‐HPOD, ranging from 4 to 9% of the total HPOD, was also demonstrated. In addition, the enantiomeric ratios of the 9‐ and 13‐HPOD produced were determined at both pH optima by chiral‐phase HPLC. The results indicated that an almost racemic mixture had been obtained which can be related to either low enantioselectivity of LOX or the presence of isozymes showing complementary enantioselectivity.
Continuous production of biodiesel fuel from vegetable oil using immobilized Candida antarctica lipase
Authors: Watanabe Yomi , Shimada Yuji , Sugihara Akio , Noda Hideo , Fukuda Hideki , Tominaga Yoshio
Published: November 2006

Candida antarctica lipase is inactivated in a mixture of vegetable oil and more than 1∶2 molar equivalent of methanol against the total fatty acids. We have revealed that the inactivation was eliminated by three successive additions of 1∶3 molar equivalent of methanol and have developed a three‐step methanolysis by which over 95% of the oil triacylglycerols (TAG) were converted to their corresponding methyl esters (ME). In this study, the lipase was not inactivated even though 2∶3 molar equivalent of methanol was present in a mixture of acylglycerols (AG) and 33% ME (AG/ME33). This finding led to a two‐step methanolysis of the oil TAG: The first‐step was conducted at 30°C for 12 h with shaking in a mixture of the oil, 1∶3 molar equivalent of methanol, and 4% immobilized lipase; the second‐step reaction was done for 24 h after adding 2∶3 molar equivalent of methanol (36 h in total). The two‐step methanolysis achieved more than 95% of conversion. When two‐step reaction was repeated by transferring the immobilized lipase to a fresh substrate mixture, the enzyme could be used 70 cycles (105 d) without any decrease in the conversion. From the viewpoint of the industrial production of biodiesel fuel production, the two‐step reaction was conducted using a reactor with impeller. However, the enzyme carrier was easily destroyed, and the lipase could be used only several times. Thus, we attempted flow reaction using a column packed with immobilized Candida lipase. Because the lipase packed in the column was drastically inactivated by feeding a mixture of AG/ME33 and 2∶3 molar equivalent of methanol, three‐step flow reaction was performed using three columns packed with 3.0 g immobilized lipase. A mixture of vegetable oil and 1∶3 molar equivalent of methanol was fed into the first column at a constant flow rate of 6.0 mL/h. The eluate and 1∶3 molar equivalent of methanol were mixed and then fed into the second column at the same flow rate. The final step reaction was done by feeding a mixture of eluate from the second column and 1∶3 molar equivalent of methanol at the same flow rate. The ME content in the final‐step eluate reached 93%, and the lipase could be used for 100 d without any decrease in the conversion.
Alkali‐catalyzed alcoholysis of crambe oil and camelina oil for the preparation of long‐chain esters
Authors: Steinke Georg , Schönwiese Stefanie , Mukherjee Kumar D.
Published: November 2006

The alcoholysis of crambe and camelina oils was carried out with oleyl alcohol, alcohols derived from crambe and camelina oils, and n‐octanol using potassium hydroxide as catalyst to prepare alkyl esters. Conversions to alkyl esters were about 0% with oleyl alcohol, 20–45% with crambe and camelina alcohols, and 60% with n‐octanol. The conversion to esters for crambe and camelina oil with oleyl alcohol and n‐octanol increased with increasing molar excess of alcohol. Composition of the alkyl esters formed was as expected from the composition of the reaction partners.
Antigenicity in soybean hypocotyls and its reduction by twin‐screw extrusion
Authors: Saitoh Sanshiroh , Urushibata Masumi , Ikuta Kazuya , Fujimaki Atsuko , Harada Hiroshi
Published: November 2006

The purpose of the present study was to develop a simple method to make a low‐antigenicity food and/or feed rich in isoflavones from soybean hypocotyls. The antigenicity of soybean hypocotyls for bovine antisoybean sera was assessed by enzyme‐linked immunosorbent assay. Immunoblotting demonstrated that the antigenicity was derived from storage proteins, which were present in hypocotyls as glycinin and β‐conglycinin, and from unknown proteins. Ground soybean hypocotyls (32‐mesh sieve size) were passed through a twin‐screw extruder to reduce the antigenicity to 1% of the original activity. The degradation of antigen proteins in soybean products was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Trypsin inhibitor and urease activity were also greatly reduced. The concentrations of isoflavones were unaffected.
Functionality of dialyzed soybean extract
Authors: Kitabatake Naofumi , Fujita Yuki
Published: November 2006

The soybean extract that was dialyzed against distilled and deionized water and adjusted to pH 7.5 (dialyzed soybean extract; d‐SE) gave a transparent liquid after heating. The heated d‐SE had less beany flavor and formed a translucent gel by heating again with 0.2 M NaCl. Gelation occurred at a lower protein concentration with NaCl than that of the original soybean extract. The dynamic viscoelasticity showed that the translucent gel from the heated d‐SE was melted and gelled by the repetition of heating and cooling, indicating reversible gelsol transition. Cryoprecipitation could be avoided by the heating of d‐SE. A gel was formed at 30°C by incubation of d‐SE with NaCl. These properties of soybean extract may offer new applications as a food ingredient.
Comparison of supercritical fluid and solvent extraction methods in extracting γ‐oryzanol from rice bran
Authors: Xu Zhimin , Godber J. Samuel
Published: November 2006

Organic solvents were compared with supercritical CO2 relative to efficiency for extracting lipid and γ‐oryzanol from rice bran. A solvent mixture with 50% hexane and 50% isopropanol (vol/vol) at a temperature of 60°C for 45–60 min produced the highest yield (1.68 mg/g of rice bran) of γ‐oryzanol among organic solvents tested. The yield of γ‐oryzanol without saponification was approximately two times higher (P<0.05) than that with saponification during solvent extraction. However, the yield (5.39 mg/g of rice bran) of γ‐oryzanol in supercritical fluid extraction under a temperature of 50°C, pressure of 68,901 kPa (680 atm), and time of 25 min was approximately four times higher than the highest yield of solvent extraction. Also, a high concentration of γ‐oryzanol in extract (50–80%) was obtained by collecting the extract after 15–20 min of extraction under optimized conditions.
Continuous production of fatty acids from palm olein by immobilized lipase in a two‐phase system
Authors: H‐Kittikun Aran , Prasertsan Poonsuk , Sungpud Chatchai
Published: November 2006

Commercial lipases were tested for the ability to hydrolyze palm olein in isooctane in a two‐phase system. Lipase OF (from Candida rugosa) showed the highest specific activity of 209 U/mg protein where 1 U is the amount of lipase enzyme required to produce 1 μmol of fatty acid (as palmitic acid) per minute. The enzyme was adsorbed completely on Accurel EP 100 (particle size <200 μm) with 20.5% activity retained. The soluble and the immobilized lipase OF showed optimal activity at the same pH and temperature (pH 6.5–7.5 and 35°C). However, the immobilized lipase had a wider range of pH and higher temperature stability. Continuous hydrolysis of palm olein was performed in a packed‐bed reactor with 656 U of immobilized enzyme. The substrate (20% palm olein in isooctane) and Tris/maleate buffer were fed concurrently at the flow rates of 0.08 and 0.04 mL/min, respectively. The system gave a degree of hydrolysis (DH) of 90–100% for up to 250 h. A more stable system allowing for more than 300 h operation at DH>95% was achieved by mixing the immobilized enzyme with 1000–1500 μm Accurel EP100 to increase the system porosity and continuous feeding of the aqueous phase recycling from the product mixture. A similar result was also obtained using 1007 U of the immobilized enzyme and 60% palm olein in isooctane fed at 0.06 mL/min.
Rapid method for determining moisture content in crude palm oil by Fourier transform infrared spectroscopy
Authors: Che Man Y. B. , Mirghani M. E. S.
Published: November 2006

A simple, rapid, and direct Fourier transform infrared (FTIR) spectroscopic method was developed for the determination of moisture content of crude palm oil (CPO). The calibration set was prepared by adding double‐distilled water to dried CPO in ratios (w/w) between 0 and 13% moisture. A partial least squares (PLS) regression technique was employed to construct a calibration model followed by cross‐validation step. The accuracy of this method was comparable to the accuracy of the American Oil Chemists' Society's vacuum oven method, which is used for determination of moisture and volatile matter, with mean difference (MDa) of 0.0105, a coefficient of determination (R2) and a standard error of calibration (SEC) of 0.9781 and 0.91, respectively. It is also comparable to the accuracy of the International Union of Pure and Applied Chemistry's distillation method with MDa, R2, and SEC of 0.0695, 0.9701, and 0.65, respectively. The study showed that midband FTIR spectroscopy combined with the PLS regression calibration technique is rapid and accurate for determination of moisture content of CPO samples with a total analysis time of less than 2 min and less than 2 mL of sample.
Analysis of the induction period of oxidation of edible oils by differential scanning calorimetry
Authors: Šimon P. , Kolman Ĺ. , Niklová I. , Schmidt Š.
Published: November 2006

Oxidation of rapeseed and sunflower oils has been studied by differential scanning calorimetry under non‐isothermal conditions and by Oxidograph under isothermal conditions for various temperatures. The parameters of an Arrhenius‐like equation describing the temperature dependence of induction period have been obtained. A new method for evaluation of the parameters from nonisothermal diffential scanning calorimetry measurements, based on the dependence of onset temperature of the oxidation peak on heating rate, is presented. It has been shown that the method gives parameters not affected by systematic errors. These can be used in modeling the oxidation process where the effects of oxygen diffusion, heat transfer, and evolution of reaction heat are explicity involved. The results obtained by differential scanning calorimetry are compared with the Oxidograph measurements. The discrepancies between the results obtained by the two methods are accounted for by oxygen diffusion within the samples.
Effects of frying and storage on cholesterol oxidation in minced meat products
Authors: Larkeson B. , Dutta P. C. , Hansson I.
Published: November 2006

The presence of cholesterol oxidation products (COP) in the diet is a health concern for their various known adverse effects. It is important that the generation of COP be assessed during different stages of production, handling, and storage of meats and meat products so that relevant measures can be taken to minimize the production of COP. In a preliminary study, we investigated the content of COP in the lipids of raw meatballs (50% prok+50% beef), prefried meatballs (50% pork +50% beef), raw hamburger (100% beef), and prefried burger (50% pork+50% beef). Six of the common COP, viz 7α‐ and 7β‐hydroxycholesterol, 7‐ketocholesterol, 5α,6α‐epoxycholestanol, 5β,6β‐epoxycholestanol, and cholestanetriol, were analyzed by gas chromatography (GC) and GC‐mass spectroscopy. The total content of these COP was in the range of 7 to 10 μg/g lipids in raw meatballs, prefried meat balls, and raw hamburger, after frying these samples for consumption. The prefried hamburger had ca. 8μg/g lipids of the total COP before frying, and this amount increased to 29 μg/g lipids after frying. During the storage of this fried sample, the total COP increased to 42 and 50 μg/g lipids, after 1 and 2 wk of storage, respectively. The results of this study show that freshly prepared meat products are a minor source of COP in the diet. However, if semiprepared frozen meat products are fried once and then stored for future consumption, the levels of COP can increase considerably, and this may be of concern for certain groups of consumers.
Pinoresinol and 1‐acetoxypinoresinol, two new phenolic compounds identified in olive oil
Authors: Brenes Manuel , Hidalgo Francisco J. , García Aranzazu , Rios José J. , García Pedro , Zamora Rosario , Garrido Antonio
Published: November 2006

Polyphenols of olive oil show autoprotective, sensory, and nutritional‐therapeutic effects. Two new phenolic compounds have been isolated from virgin olive oils by preparative high‐performance liquid chromatography and their structures established on the basis of their mass spectra and nuclear magnetic resonance spectral data. The compounds identified are the lignans pinoresinol and 1‐acetoxypinoresinol. Both have been found in all the commercial virgin olive oils analyzed. Pinoresinol concentration was rather similar in all the oils. In contrast, 1‐acetoxypinoresinol concentration was higher in oils of the Arbequina and Empeltre cultivars than in Picual or Picudo cultivars. Pinoresinol and 1‐acetoxypinoresinol may represent the major phenolic compounds in some Arbequina and Empeltre oils. Lignans possess biological and pharmacological properties and, therefore, the two new compounds identified in olive oils may contribute to the reported beneficial effects which are attributed to polyphenols on human health of a diet rich in olive oil.
Production of structured lipids by lipase‐catalyzed interesterification in a flat membrane reactor
Authors: Xu X. , Balchen S. , Jonsson G. , Adler‐Nissen J.
Published: November 2006

The application of membrane technology to the enzymatic production of specific structured lipids has been investigated in this work. Membrane screening was carried out in a membrane diffusion cell. Twenty‐six flat membranes of different materials were tested using rapeseed oil and capric acid. The suitable membranes were selected in terms of higher fatty acid and lower rapeseed oil permeation rates. The stability of membranes and the effect of fatly acid chain length on effluent fluxes were also investigated. Reaction experiments were carried out in a membrane reactor between medium‐chain triacylglycerols and n−3 polyunsaturated fatty acids (PUFA) from fish oil. Lipozyme IM was used as the biocatalyst. The incorporation of PUFA into medium‐chain triacylglycerols was increased by about 15% in a PUFA 90‐h reaction by simultaneous separation of the released medium‐chain fatty acids, compared to no separation under the same reaction conditions. It has thus clearly been demonstrated that membrane‐assisted separation improved the incorporation of acyl donors into oils beyond the reaction equilibrium defined by the original substrate concentration.