bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface tension of protein and insoluble lipids at the air‐aqueous phase interface
Authors: NiɁo Ma Rosario Rodríguez , Patino Juan M. Rodríguez 
Published: May 2007

AbstractThe surface activity of bovine serum albumin (BSA) in water and aqueous solutions of ethanol (0.5, 1.0, and 2.0 M) and sucrose (0.5 and 1.0 M) has been investigated over a range of protein concentrations (5–1.10−5, % w/w). The surface tension data were determined by the Wilhelmy plate method. Surface data at low protein concentrations indicate a low surface activity, which rises to a plateau as the monolayer is saturated at higher protein concentrations. The protein concentration and surface tension at the plateau depend on the aqueous phase composition. The effect of aqueous phase composition on BSA‐lipid interactions has been investigated by spreading an insoluble lipid (monostearin or monoolein) on a film of BSA previously adsorbed on the interface. The existence of protein‐lipid interactions depends on the protein/lipid ratio. The surface activity of mixed BSA‐lipid films is determined by the lipid because the surface pressure of the mixed film is the same as the lipid equilibrium spreading pressure, and the monolayer is not saturated by BSA. However, the surface activity of mixed BSA‐lipid films is determined by BSA as the monolayer is saturated by the protein.
Surface tension of bovine serum albumin and tween 20 at the air‐aqueous interface
Authors: NiɁo Ma Rosario Rodríguez , Patino J. M. Rodríguez 
Published: May 2007

AbstractInterfacial properties (surface tension, σ, and critical micelle concentration, CMC) of aqueous solutions of Tween 20 (polyoxyethylene sorbitan monolaurate) and/or bovine serum albumin (BSA) were evaluated. Temperature, Tween 20 concentration in the aqueous phase, BSA/Tween 20 ratio, and aqueous phase composition [water, ethanol (0.5, 1.0, and 2.5 M), and sucrose (0.5 M)] were the variables studied. The CMC of Tween 20 was determined by surface tension measurements (Wilhelmy plate method). The existence of BSA‐Tween 20 interactions was deduced from surface tension measurements. The results show that the effect of temperature on CMC depends on the aqueous phase composition, but the σ value at CMC, σCMC, does decrease as temperature is increased. The CMC and σCMC values also depend on the aqueous phase composition. In aqueous ethanol solutions, the CMC increases, but σCMC decreases. However, in sucrose aqueous solutions, the CMC decreases, but there is no significant effect on σCMC. The BSA‐Tween 20 interactions at the interface depend on both Tween 20 concentration (C) and solute in the bulk phase. In water and aqueous solutions of ethanol and sucrose, σ values decrease in the presence of protein at C<CMC but are practically independent of C at C>CMC. This is an indication that the interfacial characteristics of the mixed film are determined by either the protein or the lipid at the higher and lower protein/lipid ratio, respectively. In the intermediate region, the existence of BSA‐Tween 20 interactions dominates the interfacial characteristics of mixed films.
The influence of chemical interesterification on physicochemical properties of complex fat systems 1. Melting and crystallization
Authors: Marangoni Alejandro G. , Rousseau Dérick 
Published: May 2007

AbstractThe effects of blending palm oil (PO) with soybean oil (SBO) and lard with canola oil, and subsequent chemical interesterification (CIE), on their melting and crystallization behavior were investigated. Lard underwent larger CIE‐induced changes in triacylglycerol (TAG) composition than palm oil. Within 30 min to 1 h of CIE, changes in TAG profile appeared complete for both lard and PO. PO had a solid fat content (SFC) of ∼68% at 0°C, which diminished by ∼30% between 10 and 20°C. Dilution with SBO gradually lowered the initial SFC. CIE linearized the melting profile of all palm oil‐soybean oil (POSBO) blends between 5 and 40°C. Lard SFC followed an entirely different trend. The melting behavior of lard and lard‐canola oil (LCO) blends in the 0–40°C range was linear. CIE led to more abrupt melting for all LCO blends. Both systems displayed monotectic behavior. CIE increased the DP of POSBO blends with ≥80% PO in the blend and lowered that of blends with ≤70% PO. All CIE LCO blends had a slightly lower DP vis‐à‐vis their noninteresterified counterparts.
Isothermal crystallization of hydrogenated sunflower oil: I—Nucleation
Authors: Herrera M. L. , Falabella C. , Melgarejo M. , AɁón M. C. 
Published: May 2007

AbstractNucleation kinetics of sunflower seed oil, which was hydrogenated under two different conditions, was studied by means of a polarized light microscope and an optical setup with a laser as the light source. When the laser was used, observed induction times were shorter than the ones measured by the microscope. The laser method was found to be more sensitive and accurate. Two different crystallization behaviors were found depending on the chemical composition of the samples. Samples with high content of trielaidin crystallized in the β form at temperatures close to the melting points. They exhibited both β′ and β forms depending on crystallization temperature, as happens in natural semisolid fats such as palm oil. Samples with high content of mixed oleic and elaidic triacylglycerols crystallized in the β′ form even at temperatures close to the melting points and they did not show β form under the conditions used in this study. Activation free energies of nucleation for hydrogenated sunflower seed oil were low for the two hydrogenation conditions. It can be concluded that nucleation of sunflower seed oil is a fast process and initially needs low supercooling. These results are also important from a practical point of view for processing design, especially in regards to processes in which fats should be completely crystallized by the end of the production line.
Determination of phospholipids in vegetable oil by fourier transform infrared spectroscopy
Authors: Nzai J. M. , Proctor A. 
Published: May 2007

AbstractA method was developed to determine the total phospholipid content in vegetable oil by Fourier transform infrared spectroscopy (FTIR). Calibration curves of I‐α‐phosphatidylcholine (PC), I‐α‐phosphatidylethanolamine (PE), and I‐α‐phosphatidylinositol (PI) in hexane were generated at different concentrations. The optimal phospholipid absorption bands between 1200–970 cm−1 were identified and used for quantitative determination. High R2≥0.968 were observed between band areas and phospholipid standard concentrations. Phospholipids from crude soybean oil were obtained by water degumming, and purification was performed on a silicic acid column. The phospholipid contents of purified phospholipid extract, degummed and crude soybean oil determined from calibration equations were >90, 0.0113, and 1.77%, respectively. High correlations of determination (R2≥0.933) were observed between the FTIR method and thin‐layer chromatography‐imaging densitometry method for the determination of phospholipid content. FTIR was found to be a useful analytical tool for simple and rapid quantitative determination of phospholipids in vegetable oil.
Total fatty acid analysis of vegetable oil soapstocks by supercritical fluid extraction/reaction
Authors: King Jerry W. , Taylor Scott L. , Snyder Janet M. , Holliday Russell L. 
Published: May 2007

AbstractSoapstock from vegetable oil refining operations is a value‐added by‐product that finds further industrial use based on its fatty acid content. Since the fatty acid content of soapstock can vary according to its vegetable oil source or method of refining, determination of its total fatty acid (TFA) by an accurate analytical method is of key importance to purchasers of this refinery by‐product. Traditionally, the TFA content of soapstock has been determined by the AOCS Official Method G3‐53 based on a gravimetric assay. Unfortunately, this gravimetric‐based assay requires considerable time and incorporates a considerable quantity of organic solvent per assay. In this study, the authors have applied supercritical fluid extraction (SFE) with an enzymatic‐based reaction (SFR), in the presence of supercritical carbon dioxide (SC‐CO2), to determine the TFA content of soapstocks. The SFE/SFR sequence was conducted using two commercially available extractors using an in situ supported lipase in the extraction cell to form fatty acid methyl esters (FAME). Gas chromatographic (GC) determination of the individual FAME, followed by quantitation based on the calculated sum of all the fatty acids from the GC analysis, allowed a precise determination to be made of the soapstock’s TFA content. The TFA contents of three different soapstocks determined by this method were slightly higher than the values derived from Official Method G3‐53. The reported method takes less than one‐half of the time of Official Method G3‐53 and reduces organic solvent use from 575 mL to under 2 mL of solvent by using SC‐CO2.
Characterization of fatty acid isomers in dehydrated castor oil by gas chromatography and gas chromatography‐mass spectrometry techniques
Authors: Ramamurthi Suresh , Manohar Venkat , Mani V. V. S. 
Published: May 2007

AbstractFatty acid isomers present in dehydrated castor oil were analyzed by gas chromatography and gas chromatography‐mass spectrometry (GC‐MS) of their dimethyl oxazoline derivatives. Conjugated linoleic acid 9,11 and 10,12 isomers were identified by GC based on equivalent chainlengths. Segmental peak analysis of GC‐MS total ion chromatogram mass fragmentation pattern revealed the presence of 7,9 and 8,10 conjugated linoleic acids along with 9,11 and 10,12 conjugated linoleic acids. Interestingly, a reverse elution of trans, trans‐conjugated linoleic acids was observed, viz. 10,12 was followed by 9,11, which was in turn followed by the 8,10 and 7,9 isomers. The observed reverse order of elution was in contrast to the conventional elution pattern of both nonconjugated and conjugated cis,cis‐, cis,trans‐ and trans,cis‐isomers.
Chemical composition of commercial cornicabra virgin olive oil from 1995/96 and 1996/97 crops
Authors: Salvador M. D. , Aranda F. , Fregapane G. 
Published: May 2007

AbstractThe chemical composition of commercial Cornicabra virgin olive oils (n=65) was studied, as was its relationship with oil quality and the influence of the extraction method and production year. The main characteristics of these olive oils were: oxidative stability 53 ± 24 h, mean polyphenol content 162 ± 57 mg/kg (as gallic acid), oleic acid 80.8 ± 0.9%, linoleic acid 4.6 ± 0.6%, and campesterol 4.3 ± 0.1%, which is peculiar to this variety. No clear differences in composition were observed with respect to the different extraction systems (dual‐phase/triple‐phase decanters and pressure), although oils produced by the dual‐phase decanter showed higher oxidative stability and polyphenol content. There were significant differences in major fatty acids and sterols according to the production year.
Autoxidation of the furan fatty acid ester, methyl 9,12‐epoxyoctadeca‐9,11‐dienoate
Authors: Sehat N. , Yurawecz M. P. , Roach J. A. G. , Mossoba M. M. , Eulitz K. , Mazzola E. P. , Ku Y. 
Published: May 2007

AbstractThe objective of this study was to identify autoxidation products of methyl 9,12‐epoxyoctadeca‐9,11‐dienoate (F9,12). Previous work has shown that F9,12 is a product both of autoxidation and singlet oxygen oxidation of the methyl ester derivative of conjugated linoleic acid (CLA). F9,12, 95% pure, was synthesized from methyl ricinoleate. The synthetic F9,12 was heated at 50°C in sealed tubes containing air. Each tube contained 6 mg F9,12 and 1 mg methyl stearate as an internal standard. Samples were taken at 4.5, 7, 23, 46.5, 69.5, and 93 h. The oxidized F9,12 was dissolved in isooctane and analyzed by gas chromatography (GC), GC‐direct deposition‐Fourier transform infrared spectroscopy, and GC‐electron ionization mass spectrometry. CLA methyl ester was oxidized in a similar manner. Under these conditions, the half‐lives of CLA and F9,12 were 40 and 35 h, respectively. Oxidation products of F9,12 that were identified included: 5‐hexyl‐2‐furaldehyde (I), methyl 8‐oxooctanoate (II), methyl 13‐oxo‐9,12‐epoxytrideca‐9,11‐dienoate (III), methyl 8‐oxo‐9,12‐epoxy‐9,11‐octadecadienoate (IV), and methyl 13‐oxo‐9,12‐epoxy‐9,11‐octadecadienoate (V).
Concerns for the determination of free fatty acid in cottonseed
Authors: Wan P. J. , Pakarinen D. R. , Wakelyn P. J. 
Published: May 2007

AbstractThe official AOCS method for the determination of free fatty acid (FFA) in cottonseed requires dehulling the seed, grinding the meats with a 12‐blade food processor, and extracting the ground meats in a butt tube with three portions of room‐temperature petroleum ether. The extracted oil, after desolventization, is then titrated with NaOH to the end point of phenolphthalein in a mixed solvent of isopropanol and hexane. Our study showed that this procedure tends to underestimate the amount of FFA present in the oil of cottonseed by as much as 11.5%. It was also found that to obtain consistent and accurate FFA content, a desirable particle size is smaller than 10 mesh (preferably <14 mesh), minimum extraction temperature should be no less than 40°C (preferably greater than 50°C), and the extraction time should be longer than 2 h in a Soxhlet extractor.
Synthesis of polyunsaturated fatty acid‐enriched triglycerides by lipase‐catalyzed esterification
Authors: Cerdán L. Esteban , Medina A. Robles , Giménez A. Giménez , González M. J. IbáɁez , Grima E. Molina 
Published: May 2007

AbstractThis paper reports on the synthesis of triglycerides by enzymatic esterification of polyunsaturated fatty acids (PUFA) with glycerol. A PUFA concentrate obtained from cod liver oil was used to optimize the reaction to favor triglyceride synthesis with lipases. The type and amount of lipase and organic solvent, glycerol content, temperature, water content, and amount and time of addition of molecular sieves were studied. The optimal reaction mixture and conditions were: 9 mL hexane, 60°C, 0.5% (vol/vol) water, 1 g molecular sieves added after 24 h of reaction, glycerol/fatty acid molar ratio 1:3 and 100 mg of Novozym 435 (Novo Nordisk A/S) lipase. Under these conditions, an enriched triglyceride yiedl of 84.7% containing 27.4% eicosapentaenoic acid and 45.1% docosahexaenoic acid was obtained from a cod liver oil PUFA concentrate.
Enzymatic interesterification of lard and high‐oleic sunflower oil with Candida antarctica lipase to produce plastic fats
Authors: Seriburi Vimon , Akoh Casimir C. 
Published: May 2007

AbstractLard and high‐oleic sunflower oil (Trisun® Extra) were interesterified at 55°C for 24 h with SP435 lipase from Candida antarctica to produce plastic fats. As the amount of trisun increased, percentage free fatty acid, unsaturated fatty acid/saturated fatty acid value, oxidizability, and the amount of 18:1 found at the sn‐2 position of triglyceride products increased. Differential scanning calorimetry showed that the low‐melting components in the product contained more 18:1 than the high‐melting components. A 60:40 (w/w) ratio of lard to trisun had the widest plastic range (3–26°C). The scaled‐up reaction to produce this blend resulted in a product that had 60.1% 18:1 at the sn‐2 position compared to 44.9% for the physical blend. The solid fat content of the 60:40 interesterified mixture resembled soft‐type margarine oil.
Modification of butterfat by selective hydrolysis and interesterification by lipase: Process and product characterization
Authors: Balcão Victor M. , Kemppinen Asmo , Malcata F. Xavier , Kalo Paavo J. 
Published: May 2007

AbstractButterfat was chemically modified via combined hydrolysis and interesterification, catalyzed by a commercial lipase immobilized onto a bundle of hydrophobic hollow fibers. The main goal of this research effort was to engineer butterfat with improved nutritional properties by taking advantage of the sn‐1,3 specificity and fatty acid specificity of a lipase in hydrolysis and ester interchange reactions, and concomitantly decrease its level of long‐chain saturated fatty acid residues (viz., lauric, myristic, and palmitic acids) and change its melting properties. All reactions were carried out at 40°C in a solvent‐free system under controlled water activity, and their extent was monitored via chromatographic assays for free fatty acids, esterified fatty acid moieties, and triacylglycerols; the thermal behavior of the modified butterfat was also assessed via calorimetry. Lipase‐modified butterfat possesses a wider melting temperature range than regular butterfat. The total saturated triacylglycerols decreased by 2.2%, whereas triacylglycerols with 28–46 acyl carbons (which contained two or three lauric, myristic, or palmitic acid moieties) decreased by 13%. The total monoene triacylglycerols increased by 5.4%, whereas polyene triacylglycerols decreased by 2.9%. The triacylglycerols of interesterified butterfat had ca. 10.9% less lauric, 10.7% less myristic, and 13.6% less palmitic acid residues than those of the original butterfat.
Enzymatic glycerolysis of soybean oil
Authors: Noureddini H. , Harmeier S. E. 
Published: May 2007

AbstractEnzymatic glycerolysis of soybean oil was studied. Of the nine lipases that were tested in the initial screening, Pseudomonas sp. resulted in the highest yield of monoglycerides. Lipase from Pseudomonas sp. was further studied for the influence of temperature, thermal stability, enzyme/oil ratio, and glycerol/oil ratio. A full factorial optimization approach was performed. The following conditions were tested over the specified ranges: temperature (30–70°C), thermal stability (30–70°C), enzyme/oil ratio (0.05–0.2 g enzyme/10 g oil), glycerol/oil ratio (1:1–3:1 glycerol/oil molar ratio) and 1 h reaction time. The stability of the enzyme at the reaction temperature was also incorporated as a separate variable. At temperatures above 40°C enzyme denaturation offset the higher activity. The optimal conditions were selected to be the basis for a continuous process: 40°C, a glycerol/oil molar ratio of 2:1, and an enzyme/oil ratio of 0.1 g enzyme/10 g oil. A definition for glycerolysis activity was adopted. The glycerolysis activity (1 GU) was defined as the amount of enzyme necessary to consume 1 µmol of substrate (glycerol and oil) per minute. This research is intended to explore the reaction parameters that are important in a continuous enzymatic glycerolysis process.
γ‐Linolenic acid in zygomycetous fungi: Syzygites megalocarpus
Authors: Weete J. D. , Shewmaker F. , Gandhi S. R. 
Published: May 2007

AbstractThe fatty acids of over 150 species and isolates of zygomycetous fungi were analyzed, and it was found that γ‐linolenic acid (GLA) composed 35 to 62% of the total fatty acids in several species, i.e., Circenella simplex, Mucor indicus, Syzygites megalocarpus (ATCC 18025), and Zygorhynchus moellierie A (UAMH 1556). Further study of S. megalocarpus showed that the total lipid content of the mycelium could be increased from 9.8% of the dry biomass to 20 to 25% when grown in a medium with a high carbon/nitrogen ratio. Under these conditions, the GLA content of the triacyglycerols increased during culture development, even during the stationary phase, but remained relatively constant in the phospholipid fraction. Nonsaponifiable lipid represented 4% of the total lipid, and the major sterol among 14 others detected was ergosterol at 52% of the total. Phospholipids composed 7% of the total lipid with phosphatidylethanol‐amine and phosphatidylcholine representing 53 and 39% of the total, respectively.
Effect of pro‐oxidants on the occurrence of 2‐pentyl pyridine in soy protein isolate
Authors: Boatright W. L. , Crum A. D. , Lei Q. 
Published: May 2007

AbstractLevels of 2‐pentyl pyridine in hexane‐defatted soybean flours prepared from Burlison, Stressland, and Probst varieties and a variety null for lipoxygenase 1, 2, and 3 were determined using an internal standard of deuterium‐labeled 2‐pentyl pyridine. These defatted flours contained from 0.06 to 0.51 ppm 2‐pentyl pyridine. The flours from lipoxygenase‐null and Stressland varieties of soybeans contained the lowest levels. Control freeze‐dried soy protein isolates (SPI) prepared from defatted‐flours all contained from 0.16 to 0.18 ppm 2‐pentyl pyridine.Adding pro‐oxidants (FeCl3, CuCl2) or exposing the protein slurries to ultraviolet light during SPI processing increased the level of 2‐pentyl pyridine in the protein isolates by up to 1256 percent above the control Burlison, Stressland, and Probst SPI. The CuCl2 and/or UV treatment contributed the largest increase in each case. The same pro‐oxidant and UV treatments contributed no significant increases in the level of 2‐pentyl pyridine in the protein isolates from the lipoxygenase null SPI.
Key odorants of french fries
Authors: Wagner Robert K. , Grosch Werner 
Published: May 2007

AbstractTwenty‐one compounds, which had been screened in preceding experiments as potent odorants of french fries prepared in palm oil (PO), were quantified by stable isotope dilution assays. Nineteen odorants were dissolved in sun‐flower oil in concentrations equal to those in PO. The flavor profile of the model obtained was close to that of a real sample of PO. A comparison of the complete model with models lacking one or more compounds indicated the following key odorants of PO: 2‐ethyl‐3,5‐dimethylpyrazine, 3‐ethyl‐2,5‐dimethylpyrazine, 2,3‐diethyl‐5‐methylpyrazine, 3‐isobutyl‐2‐methoxypyrazine, (E,Z)‐ and (E,E)‐2,4‐decadienal, trans‐4,5‐epoxy‐(E)‐2‐decenal, 4‐hydroxy‐2,5‐dimethyl‐3(2H)‐furanone, methylpropanal, 2‐ and 3‐methylbutanal, and methanethiol. Replacement of palm oil by coconut fat led to a coconut note in the profile of french fries. γ‐Octalactone was identified as a major contributor to this note.
Effect of vacuum frying on the oxidative stability of oils
Authors: Shyu Shyi‐Liang , Hau Lung‐Bin , Hwang Lucy Sun 
Published: May 2007

AbstractThe purpose of this study was to evaluate frying oil quality with different assessment methods during vacuum frying of carrot slices. In six consecutive days, palm oil, lard, and soybean oil were fried under vacuum at 105°C for 20 min each hour in an 8‐h shift. Peroxide value, acid value, carbonyl value, total polar components, dielectric constant (Food Oil Sensor reading), viscosity, and fatty acid composition were used to evaluate the quality of these oils. Results showed that palm oil and lard possess greater thermal stability than soybean oil. The decrease in C18:2/C16:0 ratio was greater for soybean oil than the other two oils. Of the assessment methods used, peroxide value, carbonyl value, total polar components, and dielectric constant all showed good correlation with frying time and between each other. Viscosity was suitable to assess vacuum‐fried lard and soybean oil, but not palm oil. The measurement of dielectric constant, on the other hand, appeared to be unsuitable to assess vacuum‐fried soybean oil.