bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of used frying oil quality and natural tocopherol content on oxidative stability of fried potatoes
Authors: Ruiz G. Márquez , Polvillo M. Martín , Jorge N. , Ruiz Méndez M. V. , Dobarganes M. C. 
Published: May 2007

AbstractSunflower oil (SO) and high‐oleic sunflower oil (HOSO) were used to prepare fried potatoes by either discontinuous or continuous laboratory frying. Fried potatoes that had been fried in oils of differing quality were stored at 60°C for up to 30 d and evaluated for polar compounds, polymers, peroxide value, oil stability index, and α‐tocopherol content. Results obtained through the various methods applied were consistent and indicated that the length of the induction period could not be explained only on the basis of the degree of unsaturation or polar compound levels in fried potatoes before storage. α‐Tocopherol content also had a significant influence as potatoes fried in HOSO, with 16% polar compounds and only 10 mg/kg α‐tocopherol at the starting point of storage, were oxidized more rapidly than potatoes fried in SO with a comparatively higher degradation level, 19% polar compounds, and 100 mg/kg α‐tocopherol.
Contribution of chemical components of cornicabra virgin olive oils to oxidative stability. A study of three successive crop seasons
Authors: Salvador M. D. , Aranda F. , Fregapane G. 
Published: May 2007

AbstractOxidation is the primary cause of virgin olive oil quality deterioration. This paper presents a correlation between oxidative stability, as determined by the Rancimat method, and some chemical components involved in the oxidation process of a set of 74 Cornicabra virgin olive oils obtained from three successive crop seasons (94/95 to 96/97). Results showed a clear influence of total polyphenols on virgin olive oil stability, with linear regression coefficients which were similar for the three seasons studied, and a much lower contribution of α‐tocopherol and unsaturated fatty acids, mainly linoleic acid. A significant effect dependent on the crop season was also observed.
Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances
Authors: Cai R. , Arntfield S. D. , Charlton J. L. 
Published: May 2007

AbstractStructural changes in sinapic acid during autoclaving were studied using spectral analysis, thin‐layer chromatography, high‐performance liquid chromatography, nuclear magnetic resonance (NMR), and mass spectroscopy. Color properties of sinapic acid and its derivatives were studied by determining the transmittance spectrum, calculating the Commission Internationale de l’Eclairage 1931 tristimulus values and converting to Hunter L a b values. It was found that the colorless sinapic acid aqueous solution (100 µg/mL) turned yellow after 15 min in an autoclave at 121°C and 0.1 MPa. Filtering the yellow aqueous solution through a 0.45‐µm filter removed a brown solid consisting of at least three undetermined colored substances and left a yellow liquid. A newly developed yellow substance, syringaldehyde, was identified in the liquid phase by comparing the NMR and mass spectra of the unknown with those of authentic syringaldehyde. Thomasidioic acid was also found in the liquid phase. Under the same autoclaving conditions, sinapine bisulfate showed no evidence of any structural or color changes.
Assessment of lipase‐ and chemically catalyzed lipid modification strategies for the production of structured lipids
Authors: Willis Wendy M. , Marangoni Alejandro G. 
Published: May 2007

AbstractThe purpose of the present study was to devise a two‐step reaction to produce partial glycerides, which would subsequently be used as substrates in both lipase‐catalyzed and chemically catalyzed esterification reactions with caprylic acid. The yields and kinetics of these two‐step reactions were compared to established lipase‐catalyzed acidolysis and transesterification as well as to chemical transesterification reactions. Acyl migration did not occur during the hydrolysis or short‐path distillation steps in the preparation of free fatty acid‐free partial glycerides for esterification reactions. No significant differences in final yields (59.9% to 82.8% w/w of total triacylglycerols) of new structured lipids were detected among lipase‐catalyzed (24 h) and chemically catalyzed (5 h) reactions; however, the yield of new structured triacylglycerols (TAG) after 2 h was lower for acidolysis than for the other lipase‐catalyzed reactions (P≤0.05). Since no differences in final yields were detected among the reactions, chemical esterification using hydrolyzed oil could represent the best synthetic option, since it offers the advantage of positional distribution control associated with lipase‐catalyzed reactions as well as rapid reaction times associated with chemically catalyzed reactions. Attempts to evaluate the positional distribution of caprylic acid using allyl magnesium bromide (Grignard reagent) were hampered by production of unknown species, which prevented accurate determination of the concentration of some key fatty acids.
Production of a very low saturate oil based on the specificity of Geotrichum candidum lipase
Authors: Diks R. M. M. , Lee M. J. 
Published: May 2007

AbstractLipase B (GCB) produced by the fungus Geotrichum candidum CMICC 335426 is known for its high specificity towards cis‐Δ9 unsaturated fatty acids. The wild‐type lipase (not genetically modified) as well as the lipase obtained by heterologous expression of the corresponding gene in Pichia pastoris (genetically modified) were studied in a process aiming to produce an oil containing very little saturated fatty acids (SAFA). The approach described in this paper is based on the selective hydrolysis of sunflower oil (12% SAFA) using the G. candidum type B (GCB) lipases. Depending on the lipase input, up to 60% w/w degree of hydrolysis was obtained within 6–8 h. Because of the high specificity of the GCB lipases (specificity factor ∼30), the level of unsaturates in the free fatty acid fraction was >99% w/w. In contrast with literature data, no loss of specificity was observed, even at the highest degree of hydrolysis obtained. Though both GCB lipases are stable at 30°C, the rate of hydrolysis decreased considerably during the process. Product inhibition as well as time‐dependent deactivation (half‐life ≈2 h) were shown to be involved. After separation of the oil phase, the unsaturated free fatty acids were recovered from the mixture by evaporation and reconverted to triglycerides by enzymatic esterification with glycerol. Because the GCB lipases have a very low efficiency for esterification, this reaction was carried out with immobilized Rhizomucor miehei lipase. Under continuous removal of the water generated during the process, >95% triglycerides were obtained in less than 24 h. Standard deodorization resulted in an odorless, colorless, and tasteless oil with less than 1% SAFA.
Effect of genetic modification on the distribution of minor constituents in canola oil
Authors: Abidi S. L. , List G. R. , Rennick K. A. 
Published: May 2007

AbstractOil derived from different lines of genetically modified canola varieties was analyzed for phospholipids, tocopherols, and phytosterols by various chromatographic techniques. As observed previously in genetically modified soybean oils, there was a decrease in the content and composition of phosphatidic acid in three of the modified canola oils derived from the 12 varieties investigated. Normal‐phase high‐performance liquid chromatographic (HPLC) analyses showed small variations in the phospholipid content of major classes, despite few differences in their composition. Reversed‐phase HPLC data indicated that the molecular species distribution of phosphatidylethanolamine was significantly altered by genetic modification when compared to phosphatidylcholine. Impact of oilseed modification on the tocopherol content was variable, with greater variation in the concentration of α‐ and γ‐tocopherols than δ‐tocopherol. Phytosterol composition was markedly affected by genetic modification. Brassicasterol, campesterol, and β‐sitosterol levels were consistently lowered in one genotype, whereas increased brassicasterol content was observed in the other variety. In general, genetic modification of canola seeds led to changes in the distribution of phospholipids, tocopherols, and phytosterols.
The seed fatty acid composition and the distribution of Δ5‐olefinic acids in the triacylglycerols of some taxares (Cephalotaxus and Podocarpus)
Authors: Wolff Robert L. , Pédrono Frédérique , Marpeau Anne M. , Gunstone Frank D. 
Published: May 2007

AbstractThe fatty acid compositions of the seeds from four Cephalotaxus species or varieties (plum yews; Cephalotaxaceae) and two Podocarpus species (podocarps; Podocarpaceae) have been established. These compositions were compared with those previously published for some Taxaceae species (Taxus and Torreya). Cephalotaxaceae, Podocarpaceae, and Taxaceae belong to the Taxares suborder. Δ5‐Olefinic acids are present in the seed lipids from all species analyzed. In Cephalotaxus, Podocarpus, and Torreya, the prominent Δ5‐olefinic acid that occurs is the trienoic acid 5,11,14–20:3 (sciadonic) acid, comprising from 6.7 to 26.4% of total fatty acids. In these species, the Δ5,11 structure is largely favored over the Δ5,9 structure: the 5,9–18:2 (taxoleic) and 5,9,12–18:3 (pinolenic) acids are at the limit of detection, in contrast to Taxus and most Pinaceae species, where these two Δ5‐olefinic acids generally predominate. 14‐Methylhexadecanoic acid, an habitual though minor component of Pinaceae and Ginkgo biloba seed lipids, could not be detected in Cephalotaxus species studied here and was tentatively identified in trace amounts only in one Podocarpus species. In addition to sciadonic acid, Cephalotaxus and Podocarpus seeds are characterized by unusually high amounts of 11,14–20:2 acid, in the range of 3.1–12.0%. This contrasts with most of the 170 species of conifers analyzed so far (from the families Pinaceae, Cupressaceae, Taxodiaceae, Taxaceae, and Sciadopityaceae, which belong to the Pinares suborder), where this acid is generally ≤2%. A close resemblance between Torreya grandis and three of the Cephalotaxus species analyzed might be indicative of some phyletic relationship between the families Cephalotaxaceae and Taxaceae. 13C nuclear magnetic resonance spectroscopy of the seed oils from C. drupaceae and P. andinus has shown that Δ5‐olefinic acids are apparently excluded from the internal position of triacylglycerols, which is a characteristic common to all Coniferales species analyzed so far, and consequently of great antiquity.
Composition of muscle tissue lipids of silver carp and bighead carp
Authors: Vujković Gordana , Karlović Đerđ , Vujković Ivan , Vörösbaranyi István , Jovanović Branislava 
Published: May 2007

AbstractLipids have a complex role in the nutritional value of food. Some polyunsaturated fatty acids, characterized as essential, are extremely important for human health. This is primarily related to α‐linolenic acid (18:3n‐3), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3). Content of polyunsaturated n‐3 fatty acids is usually much higher in lipids of marine fish than in freshwater fish. Previous investigations have shown that muscle tissue of silver carp and bighead carp from fish farms may be a rich source of essential fatty acids. Because of that, the objective of this work was to examine contents and composition of fatty acids and total lipids in the muscle tissue of silver and bighead carp, with the aim to find out whether there are significant differences in this respect between the two species and to what extent the harvest season can influence the composition of lipids in these freshwater fish. This study showed that there is no significant difference either in the content of polyunsaturated n‐3 and n‐6 fatty acids, or in the n‐6/n‐3 fatty acid ratio in these two fish species. The lipids of both the silver and bighead carp from the spring harvest have significantly higher contents of the n‐3 acids and a significantly lower n‐6/n‐3 ratio than fish from the autumn harvest.
A simple method for regiospecific analysis of triacylglycerols by gas chromatography
Authors: Angers Paul , Arul Joseph 
Published: May 2007

AbstractA simple method for regiospecific analysis of triglycerides was developed. It consists of partial deacylation of triglycerides by ethylmagnesium bromide followed by derivatization of monoglycerides with n‐butyryl chloride, and direct analysis of dibutyrate derivatives of monoglycerides by gas chromatography. The chromatographic conditions were carried out with monoglycerides of C12 to C20 fatty acids and resulted in separation of dibutyrate derivatives between those bearing the medium‐ or long‐chain fatty acid in the sn‐1(3) and sn‐2 positions of glycerol. Beef tallow and grapeseed and cotton seed oils were analyzed using this new method, and their regiospecific distributions were compared with literature data. The method does not require separation of products by thin‐layer chromatography or special analytical equipment other than a standard gas chromatograph, and it can thus be used for routine regiospecific analysis of triglycerides.
Determination of free fatty acids in crude palm oil and refined‐bleached‐deodorized palm olein using fourier transform infrared spectroscopy
Authors: Che Man Y. B. , Moh M. H. , van de Voort F. R. 
Published: May 2007

AbstractA rapid direct Fourier transform infrared (FTIR) spectroscopic method using a 100 µ BaF2 transmission cell was developed for the determination of free fatty acid (FFA) in crude palm oil (CPO) and refined‐bleached‐deodorized (RBD) palm olein, covering an analytical range of 3.0–6.5% and 0.07–0.6% FFA, respectively. The samples were prepared by hydrolyzing oil with enzyme in an incubator. The optimal calibration models were constructed based on partial least squares (PLS) analysis using the FTIR carboxyl region (C=O) from 1722 to 1690 cm−1. The resulting PLS calibrations were linear over the range tested. The standard errors of calibration (SEC) obtained were 0.08% FFA for CPO with correlation coefficient (R2) of 0.992 and 0.01% FFA for RBD palm olein with R2 of 0.994. The standard errors of performance (SEP) were 0.04% FFA for CPO with R2 of 0.998 and 0.006% FFA for RBD palm olein with R2 of 0.998, respectively. In terms of reproducibility (r) and accuracy (a), both FTIR and chemical methods showed comparable results. Because of its simpler and more rapid analysis, which is less than 2 min per sample, as well as the minimum use of solvents and labor, FTIR has an advantage over the wet chemical method.
Rapid determination of cis and trans content, iodine value, and saponification number of edible oils by fourier transform near‐infrared spectroscopy
Authors: Li H. , van de Voort F. R. , Sedman J. , Ismail A. A. 
Published: May 2007

AbstractFourier transform near‐infrared (FT‐NIR) spectroscopy was evaluated as a means of simultaneously determining the cis and trans content, iodine value (IV), and saponification number of neat fats and oils. Reference values for these parameters were obtained from oils using a previously developed mid‐FTIR Edible Oil Analysis Package. Two partial least squares calibrations were developed for a 5‐mm heated flow cell, the first a process calibration based on hydrogenated soybean samples and the second a more generalized calibration based on an oil samplematrix containing many oil types and designed to remove any correlations among the parameters measured. Each calibration performed well with its own validation samples; however, only the noncorrelated calibration was able to analyze oil samples accurately from a variety of sources. It was found that NIR analysis maintained the internal consistency between cis/trans and IV, and the accuracy and reproducibility of the predictions were on the order of ±1.5 and ±1.0 units, respectively, for all parameters evaluated. FT‐NIR is shown to be a very workable means of determining cis/trans/IV values and saponification number for edible fats and oils, and it provides a rapid alternative to the commonly used chemical and physical methods presently employed in the industry.
Modulated temperature differential scanning calorimetry for examination of tristearin polymorphism: I. Effect of operational parameters
Authors: Singh Satish K. , Jalali Ali Fathe , Aldén Maggie 
Published: May 2007

AbstractThe transformations of tristearin were examined by modulated temperature differential scanning calorimetry (MTDSC) in order to study the effect of operational parameters on the nature of information obtained from this technique. Tristearin has been used as a model polymorphic system showing metastable phases and complicated transformation routes occurring at relatively slow rates. The parameters examined were underlying heating/cooling rates and the amplitude of modulation. The first conclusion is that MTDSC enables overlapping α‐melting and β‐crystallization events to be separated, thus increasing the information obtained compared to normal thermal analysis. Other general conclusions are that observation of reversible processes is strongly influenced by the underlying heating rate; low to moderate heating rates are recommended. Amplitude of modulation has a complicated effect on the phenomenon being studied; when studying systems that exhibit metastable or polymorphic transitions, it is recommended that a range of amplitudes be tested to enable confirmation of whether an observed ‘recrystallization’ effect is a new phase or the same phase as the one melting. Cooling with modulation disturbs the crystallization process, possibly leading to smaller or imperfect crystals; however, the phases obtained are not different compared to normal DSC. The usefulness of MTDSC in analyzing these types of complicated systems is primarily qualitative at the moment. Some recommendations have been made as to the combinations of parameters for studying such systems.
Optimizing production of ethyl esters of grease using 95% ethanol by response surface methodology
Authors: Wu W. H. , Foglia T. A. , Marmer W. N. , Phillips J. G. 
Published: May 2007

AbstractPrevious research suggested that ethyl esters derived from recycled restaurant grease might be a potential source of biodiesel. Accordingly, response surface methodology (RSM) was employed to optimize reaction parameters—temperature, time, level of lipase, mole ratio of reactants—in the PS‐30 lipase‐catalyzed transesterification reaction of grease to ethyl esters using 95% ethanol. The regression equation obtained by a modified central composite design of RSM predicted optimal reaction conditions of 38.4°C, 2.47 h, 13.7 wt% lipase (PS‐30), and a mole ratio of grease to ethanol of 1:6.6. Under these conditions the predicted optimal percentage ethyl ester yield was 85.4%. Subsequent experiments using the predicted parameter combinations indicated a trend where experimental percentage yields of ethyl ester were consistently lower than predicted values. In an effort to improve the experimental yield of esters, a second portion of PS‐30 lipase was added without success; however, the addition of 5% SP435 one hour after the start of the initial reaction increased the yield of esters to >96%. Neither lipase PS‐30 nor lipase SP435 alone, however, gave the RSM‐predicted yield of ethyl esters.
In‐line and off‐line trapping of lipids extracted from chicken liver by supercritical carbon dioxide
Authors: Li Shufen , Maxwell Robert J. , Lightfield Alan R. 
Published: May 2007

AbstractThis supercritical fluid extraction study determined the retentive properties of neutral alumina sorbent as an in‐line trap for lipids in the dynamic state over a pressure range of 490–680 bar and temperatures of 40 and 80°C. Lipids were extracted from a chicken liver matrix using supercritical carbon dioxide over a 40‐min period at a flow rate of 3 L/min (expanded gas), then were quantified by high‐performance liquid chromatography using an evaporative light‐scattering detector. Approximately 30 and 18%, respectively, of the total extracted lipids were trapped on the in‐line alumina sorbent bed at 40°C as the operating pressure increased from 490 to 680 bar, while the remaining lipids were trapped off‐line after CO2 decompression. The major lipid classes trapped in‐line were fatty acids and cholesterol, whereas only minor amounts of the less polar lipid classes such as sterol esters and triacylglycerols were retained. At 80°C and 680 bar, less than 1.5% of the extracted total lipids was trapped in‐line, indicating the lack of adsorptive selectivity for lipids by alumina under these conditions.
Isothermal crystallization of hydrogenated sunflower oil: II. growth and solid fat content
Authors: Herrera M. L. , Falabella C. , Melgarejo M. , AɁón M. C. 
Published: May 2007

AbstractIsothermal crystallization of sunflower seed oil hydrogenated under two different conditions was studied by means of pulse nuclear magnetic resonance (pNMR) and optical microscopy. Solid fat content (SFC) curves showed two different shapes depending on supercooling. When supercooling was high, hyperbolic curves were found, whereas with low supercooling sigmoidal curves were obtained. Curves were interpreted with the modified Avrami equation. Photographs of the crystals were taken from the beginning of crystallization, every 15 s until 15 min and every 5 min until 60 min. Samples which exhibited hyperbolic curves showed a slight increase in crystal number, and crystals were needle‐shaped in all cases. Samples which had sigmoidal crystallization curves showed a marked increase in crystal number with time, and crystals were spherical in shape. Crystallization behavior was also in agreement with the chemical composition of the samples. Samples which had the highest content of high‐melting triacylglycerols (especially trielaidin) showed only hyperbolic curves. Supercooling is a very important parameter that defines the way nucleation occurs. Depending on the initial number of nuclei, two different growth mechanisms were found: a uniform linear growth of the nuclei for a small initial number (sigmoidal curves) and an aggregate of the nuclei for a high initial number (hyperbolic curves).
The difference between cocoa butter and salatrim® lies in the microstructure of the fat crystal network
Authors: Narine Suresh S. , Marangoni Alejandro G. 
Published: May 2007

AbstractThe solid fat content of Salatrim® at 22°C is 9% higher than that of cocoa butter; however, its storage modulus, G′ (1 Hz), or solid‐like character, is one order of magnitude lower (2.5 MPa vs. 52 MPa). This difference may be explained by structural differences in the microstructure of the fat crystal network of the respective fat systems. Polarized light micrographs of these two confectionery fats show that cocoa butter forms a fat crystal network characterized by discrete crystalline particles which aggregate to large microstructures which then form a three‐dimensional network, while Salatrim®’s network is composed of randomly arranged noncrystalline, translucent platelets. Rheological measurements on both fat networks yielded fractal dimensions of 2.37 for cocoa butter and 2.90 for Salatrim®. Image analysis of the microstructure of cocoa butter yielded a fractal dimension of 2.31; however, the microstructure of Salatrim® does not lend itself to fractal analysis via image analysis. It was observed that the microstructure of Salatrim® is random instead of fractal. The proposition is made that the macroscopic mechanical properties of Salatrim® are related to the mechanical properties of the platelets that make up the network and the nature of the links between the platelets. Furthermore, the random spatial distribution of the platelets does not provide an indication of the strength of the network. For cocoa butter, the macroscopic mechanical properties are integrally related to the fractal spatial distribution of the solid mass in the network, the nature of the links between the microstructures, and the strength of the microstructures.