bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of various emulsifiers on the partitioning and antioxidant activity of hydroxybenzoic acids and their derivatives in oil‐in‐water emulsions
Authors: Stöckmann Heiko , Schwarz Karin , Huynh‐Ba Tuong 
Published: November 2006

AbstractThe partitioning behavior of a series of hydroxybenzoic acids and their derivatives was determined in biphasic water‐oil systems, emulsifier solutions, and oil‐in‐water (O/W) emulsions. The effect of gradually decreasing polarity on partitioning behavior and antioxidant efficiency in O/W emulsions was investigated by using gallic acid and its esters as antioxidants. Sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), polyoxyethylene 20 cetyl ether (Brij 58), and partially hydrolyzed soybean lecithin (PHLC, Emultop®) were used to investigate the influence of different classes of emulsifiers on the partitioning behavior. The antioxidant activity of gallic acid and its methyl, ethyl, propyl, butyl, and octyl esters showed markedly different trends in O/W emulsions depending on the emulsifier used. The results are discussed with respect to the properties of the emulsifiers, such as hydrogen bond basicity, hydrophobic interactions, and structural properties.
Effects of microwave and conventional baking on the oxidative stability and fatty acid composition of puff pastry
Authors: Daglioglu Orhan , Tasan Murat , Tuncel Baris 
Published: November 2006

AbstractThe effects of microwave and conventional baking on the fatty acid and trans fatty acid compositions of puff pastries, which contain high amounts of hydrogenated fat, were investigated. In addition, free fatty acids, peroxide value, and induction time for oxidative stability by the Rancimat method have been compared for microwave‐ and conventionally baked puff pastries. The data indicate there were considerable changes in acidity, peroxide value, and Rancimat induction time in both microwave‐ and conventionally baked samples. Although the content of saturated fatty acid such as palmitic and stearic and the ratio of saturated to unsaturated fatty acids did not change significantly, an apparent increase was determined in trans oleic acid levels by both baking methods. In addition, a significant decrease in linoleic acid content of the samples was found by microwave baking.
Water‐hexane sorption in sunflower meals
Authors: Cardarelli D. A. , Mattea M. A. , Crapiste G. H. 
Published: November 2006

AbstractSorption equilibria of water and hexane in sunflower meals were determined at atmospheric pressure and temperatures from 50 to 95°C. Adsorption‐desorption experiments, for both individual vapors and water‐hexane mixtures, were carried out using a dynamic technique based on gravimetric measurements with a Cahn electrobalance. The isotherms were fitted to the Guggenheim‐Anderson‐deBoer sorption equation, and the heat of sorption was evaluated from experimental results. In the range of temperatures investigated, water sorption was several times higher than hexane sorption, the differences increasing with solvent activity. The net heat of sorption that resulted was significantly higher for hexane than for water. Water sorption isotherms were slightly affected by temperature, especially at water activities greater than 0.6. Some hysteresis was observed in water sorption at 50°C, but it was practically negligible at higher temperatures. Hexane previously adsorbed in the meal did not affect significantly the sorption of water. On the contrary, water previously adsorbed in the meal increased the amount of adsorbed hexane.
Quantitative structure‐capillary column gas chromatographic retention time relationships for natural sterols (trimethylsilyl ethers) from olive oil
Authors: Acuña‐Cueva Rocío , Hueso‐Ureña Francisco , Illán Cabeza Nuria A. , Jiménez‐Pulido Sonia B. , Moreno‐Carretero Miguel N. , Martínez Martos José M. 
Published: November 2006

AbstractA study of the relationship between the capillary column gas chromatographic retention times on two different columns (SE‐54 and SE‐52) for a group of trimethylsilyl ethers derived from 16 natural sterols found in olive oil and an initial set of 60 molecular descriptors was made. Three kinds of molecular descriptors were used: conventional, topological, and quantumchemical parameters. By using multivariable regression, two empirical functions for each column were obtained, which were selected on the basis of their respective statistical parameters. The first model relates the retention index with the quantum‐chemical descriptors and the second with both topological and conventional descriptors. In all cases, the correlation coefficients of the empirical functions were higher than 0.9880, and the mean relative errors range between 2.88 and 3.24%. In any case, both models could be used, although the second model could be more useful and preferable because it has higher R2 values and a lower standard error percentage, giving slightly more exact results.
Determination of trace amounts of fatty acids in edible oils by capillary gas‐liquid chromatography
Authors: Buchgraber M. , Ulberth F. , Anklam E. 
Published: November 2006

AbstractThe effect of using different gas‐liquid chromatography (GLC) hardware to quantify low concentrations of fatty acids was studies. A fused‐silica capillary column was operated in two different chromatographs (A and B) that were interfaced to three different chromatographic data systems to process the flame‐ionization detector signals (systems A, B1, and B2). A test routine was developed that allowed the proper selection of peak processing parameters for the automatic recognition and integration of fatty acids occurring at trace levels. However, agreement of analytical results between the three analytical systems was not satisfactory; components at concentrations <0.10 g/100 g could not be quantified with high reliability, although the same capillary column and identical sample solutions were used (quasi‐repeatability conditions). Even for major fatty acids, deviations up to 1.0 g/100 g were noted, which could only be attributed to the use of different GLC hardware. Attention should be paid to these technical restrictions when formulating product specifications based on fatty acid profile parameters.
Characterization of farmed and wild salmon (Salmo salar) by a combined use of compositional and isotopic analyses
Authors: Aursand M. , Mabon F. , Martin G. J. 
Published: November 2006

AbstractGas chromatography, isotope ratio mass spectrometry, and high‐resolution 2H site‐specific natural isotope fractionation/nuclear magnetic resonance spectroscopy have been used to study the different kinds of fish oils and lipids extracted from muscle of wild and farmed salmon (Norway, Scotland). A statistical analysis of the fatty acid compositions, overall 2H and 13C isotope ratios, and molar fractions of the isotopomeric deuterium clusters was carried out to select the most efficient variables for distinguishing the different groups of salmons and fishes studied. A classification analysis based on four fatty acid compositions, three deuterium molar fractions, and the overall (D/H)tot isotope ratio of fish oils completely assings the oils to the right group.
Nuclear magnetic resonance spectroscopy and reversed‐phase high‐performance liquid chromatography of peracetylated digalactosyldiacylglycerols
Authors: Bergqvist Magnus , Holmbäck Jan 
Published: November 2006

AbstractA simple method for the peracetylation of digalactosyldiacylglycerols is described. The peracetylated compounds were isolated by thin‐layer chromatography and subjected to nuclear magnetic resonance spectroscopy for structure elucidation. The proton signals at acetylated sites are shifted downfield compared to the nonderivatized compounds, resulting in improved resolution. The peracetylated compounds were also subjected to molecular species analysis by reversed‐phase high‐performance liquid chromatography. The chromatography behavior of the peracetylated compounds was similar to that of triacylglycerols, displaying narrow and symmetrical peaks yielding a highly resolved molecular species profile.
Synthesis, purification, and characterization of structured lipids produced from chicken fat
Authors: Lee Ki‐Teak , Foglia Thomas A. 
Published: November 2006

AbstractA structured lipid (SL) was synthesized enzymatically from chicken fat by incorporating a medium‐chain length fatty acid (caprylic acid) into chicken fat triacylglycerols. Carica papaya latex was used as the biocatalyst. The optimal substrate mole ratio found was 1∶2 (chicken fat fatty acids/caprylic acid). At this ratio of reactants, the incorporation of caprylic acid (C8∶0) at 65°C was 23.4 mol%, whereas at 55°C the incorporation of caprylic acid was 17.6 mol%. A packed‐bed column bioreactor was designed for the synthesis of SL from chicken fat. In using ground crude C. papaya latex (aw<0.1), 7.1 mol% of caprylic acid was incorporated into the chicken fat triacylglycerols after 117 min of reactor residence time. After purification of the SL, the acyl positional distribution of fatty acids on the glycerol backbone was determined by 13C nuclear magnetic resonance (NMR) spectroscopy. From the NMR spectrum of the SL, it was determined that saturated fatty acyl residues at the 1,3‐positions of the SL triacylglycerols increased to 62% over that of the starting chicken fat triacylglycerols, suggesting that caprylic acid was preferentially incorporated at the 1,3‐positions. In addition, differential scanning calorimetry thermograms were obtained to compare the crystallization characteristics of the starting chicken fat with the SL prepared from it.
A new spectrophotometric method for the rapid assessment of deep frying oil quality
Authors: Xu Xin‐Qing 
Published: November 2006

AbstractA new and quick spectrophotometric method was developed to assess deep‐frying oil quality. The scanned spectrophotometric curves of the frying oil samples from 350 and 650 nm wavelength changed systematically with the duration of deep frying. The absorbances of the frying oil samples, especially those measured at 490 nm, increased significantly during frying and were significantly correlated to frying time (r ≥0.95, P<0.001). There was a strong correlation between the absorbances of a set of oil samples taken from 0 to 80 h of deep frying and total polar compound contents in the same set of oil samples analyzed using the American Oil Chemists' Society official method (r=0.974, P<0.001). The equation for conversion of the absorbances to total polar compound contents is y=−2.7865x2 +23.782x+1.0309. The absorbances of 10 different types of frying oils with samples taken from 0 to 80 h of deep frying in duplicate were also strongly correlated to total polar compounds in the same oil samples (r=0.953, P<0.001, n=220). The results show that this method is fast, simple, convenient, and reliable.
Precision and accuracy in the color specification of virgin olive oils from the bromthymol blue method
Authors: Melgosa M. , Prez M. M. , Hita E. , Moyano M. J. , Alba J. , Heredia F. J. 
Published: November 2006

AbstractTwenty experienced observers with nondefective color vision judged 27 virgin olive oil samples within an acceptable color range, using the bromthymol blue (BTB) method, under controlled observation conditions (daylight source with a correlated color temperature of 6500 K, and standard gray back‐ground). On the average, 44.8% of the observers agreed in their selections of the BTB standard solution matching a given oil sample, and this percentage increased to 88.2% considering ±one step in the two dimensions (pH and concentration) of the BTB scale. On the average, the lowest color difference between oil samples and available BTB solutions was 6.6 Commission Internationale de l'Éclairage 1976‐(L*a*b*) (CIELAB) units, but this color difference was approximately two times greater for the color difference between oil samples and BTB solutions selected by our observers. The colors of the BTB standard solutions in the CIELAB space are not uniformly distributed, and thus one step in pH or concentration is equivalent to CIELAB color differences varying in a wide range (1.7–13.5 and 1.7–26.3 CIELAB units, respectively). From these values, indicating low precision, accuracy, and uniformity, some suggestions are made for future improvements of the current BTB method.
Effects of β‐carotene and lycopene thermal degradation products on the oxidative stability of soybean oil
Authors: Steenson Donald F. , Min David B. 
Published: November 2006

AbstractThe relative oxidative stability of soybean oil samples containing either thermally degraded β‐carotene or lycopene was determined by measuring peroxide value (PV) and headspace oxygen depletion (HOD) every 4 h for 24 h. Sobyean oil samples containing 50 ppm degraded β‐carotene that were stored in the dark at 60°C displayed significantly (P<0.01) higher HOD values compared with controls. Lycopene degradation products (50 ppm) in soybean oil significantly (P<0.05) decreased HOD of samples when stored in the dark. PV and HOD values for samples containing 50 ppm of either β‐carotene or lycopene degradation products stored under lighted conditions did not differ significantly from controls (P<0.05). However, soybean oil samples containing 50 ppm of unheated, all‐trans β‐carotene or lycopene stored under light showed significantly lower PV and HOD values than controls (P<0.01). These results indicated that during autoxidation of soybean oil held in the dark, β‐carotene thermal degradation products acted as a prooxidant, while thermally degraded lycopene displayed antioxidant activity in similar soybean oil systems. In addition, β‐carotene and lycopene degradation products exposed to singlet oxygen oxidation under light did not increase or decrease the oxidative stability of their respective soybean oil samples.
Oil stability index correlated with sensory determination of oxidative stability in light‐exposed soybean oil
Authors: Coppin Elizabeth A. , Pike Oscar A. 
Published: November 2006

AbstractValidity of the oil stability index (OSI) as an accelerated test of oxidative stability has been questioned because of its high holding temperature, 110°C, which may cause reactions that would not occur at lower temperatures. The purpose of this study was to characterize the usefulness of OSI as an accelerated oxidative stability test for oil of varying metal catalyst content by correlating OSI with the sensory induction period of light‐exposed soybean oil. Five 400‐g aliquots of soybean oil were placed in Erlenmeyer flasks and treated with increasing levels of a metal pro‐oxidant, Cu2+ 2‐ethylhexanoate. Pro‐oxidant concentration ranged from 0 to 3.13×10−5 M. Five‐gram aliquots were taken from duplicate flasks and immediately tested using the Oxidative Stability Instrument. Heating block temperature was 110°C. Sample flasks were then exposed to 800 footcandles of light and held at ambient temperature for 3 wk. One‐gram aliquots were regularly withdrawn and evaluated for rancidity by 10 trained panelists to determine the sensory induction period of each sample. Aliquots were also taken to determine OSI of light‐exposed oil samples. Sensory induction periods were correlated with OSI, resulting in a squared partial correlation coefficient (r2) of 0.920. The r2 for OSI of light‐exposed oil samples ranged from 0.897 to 0.979. OSI appears to be an acceptable accelerated method for measuring the oxidative stability of light‐exposed soybean oil that varies in metal catalyst content.
Production of margarine fats by enzymatic interesterification with silica‐granulated Thermomyces lanuginosa lipase in a large‐scale study
Authors: Zhang Hong , Xu Xuebing , Nilsson Jörgen , Mu Huiling , Adler‐Nissen Jens , Høy Carl‐Erik 
Published: November 2006

AbstractInteresterification of a blend of palm stearin and coconut oil (75∶25, w/w), catalyzed by an immobilized Thermomyces lanuginosa lipase by silica granulation, Lipozyme TL IM, was studied for production of margarine fats in a 1‐ or 300‐kg pilot‐scale batch‐stirred tank reactor. Parameters and reusability were investigated. The comparison was carried out between enzymatic and chemical interesterified products. Experimentally, Lipozyme TL IM had similar activity to Lipozyme IM for the interesterification of the blend. Within the range of 55–80°C, temperature had little influence on the degree of interesterification for 6‐h reaction, but it had slight impact on the content of free fatty acids (FFA). Drying of Lipozyme TL IM from water content 6 to 3% did not affect its activity, whereas it greatly reduced FFA and diacylglycerol contents in the products. Lipozyme TL IM was stable in the 1‐kg scale reactor at least for 11 batches and the 300‐kg pilot‐scale reactor at least for nine batches. Due to regiospecificity of the lipase (sn‐1,3 specific), enzymatically interesterified products had different fatty acid distribution at sn‐2 position from the chemically randomized products, implying the potential nutritional benefits of the new technology.
Effect of alleles governing 16:0 concentration on glycerolipid composition in developing soybeans
Authors: Wilson R. F. , Marquardt T. C. , Novitzky W. P. , Burton J. W. , Wilcox J. R. , Dewey R. E. 
Published: November 2006

AbstractSoybean [Glycine max (L.) Merr.] oil typically contains 11% palmitic acid, but germplasm with recessive alleles at Fap gene loci exhibit from less than 4% to about 35% 16:0, Although these alleles are used to develop new cultivars, little is known about how they influence palmitic acid concentration. One theory suggests that fap alleles may mediate differences in triacylglycerol composition through genetic effects on the activity or substrate specificity of acyltransferases, such as diacylglycerol acyltransferase (EC 2.3.1.20). Based on logistic function analysis of developing seed, differences in fag allele expression are evident in the rate of palmitic acid accumulation in triacylglycerol, with peak deposition near mid‐seed fill. Acetate saturation kinetics also reveal a strong positive relation between the relative amount of de novo palmitic acid synthesis and the indigenous palmitic acid concentration in triacylglycerol among fap genotypes. However, no differences appear in the kinetics of palmitoyl‐CoA metabolism in developing seed of these genotypes. Therefore, the fap alleles apparently do not encode or regulate the activities of glycerolipid acyltransferase enzymes. Rather, major genetic effects on triacylglycerol composition accrue through regulation of palmitic acid production in the plastids of developing soybean cotyledons.
Melting behavior of blends of milk fat with hydrogenated coconut and cottonseed oils
Authors: Shen Z. , Birkett A. , Augustin M. A. , Dungey S. , Versteeg C. 
Published: November 2006

AbstractThe melting behavior of milk fat, hydrogenated coconut and cottonseed oils, and blends of these oils was examined by nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). Solid fat profiles showed that the solid fat contents (SFC) of all blends were close to the weighted averages of the oil components at temperatures below 15°C. However, from 15 to 25°C, blends of milk fat with hydrogenated coconut oils exhibited SFC lower than those of the weighted averages of the oil components by up to 10% less solid fat. Also from 25 to 35°C, in blends of milk fat with hydrogenated cottonseed oils, the SFC were lower than the weighted averages of the original fats. DSC measurements gave higher SFC values than those by NMR. DSC analysis showed that the temperatures of crystallization peaks were lower than those of melting peaks for milk fat, hydrogenated coconut oil, and their blends, indicating that there was considerable hysteresis between the melting and cooling curves. The absence of strong eutectic effects in these blends suggested that blends of milk fat with these hydrogenated vegetable oils had compatible polymorphs in their solid phases. This allowed prediction of melting behavior of milk‐fat blends with the above oils by simple arithmetic when the SFC of the individual oils and their interaction effects were considered.
Synthesis of δ‐eicosanolactone and δ‐docosanolactone directly from meadowfoam oil
Authors: Isbell Terry A. , Cermak Steven C. 
Published: November 2006

Abstractδ‐Eicosanolactone and δ‐docosanolactone were synthesized directly from the triacylglycerides of meadowfoam (Limnanthes) oil. Perchloric and sulfuric acids were used in stoichiometric quantities (0.5–4.0 mol equiv) to cyclize triglyceride to δ‐lactone. When the reactions were run in the absence of solvent at 40°C, δ‐lactone yields ranged from 17–75% where δ/γ ratios ranged from 6∶1 to 10.4.∶1. Sulfuric and perchloric acids gave similar yields for their individually optimized reactions. Perchloric acid‐catalyzed reactions required less acid to produce similar amounts of δ‐lactone (HClO4 at 2.0 mol equiv gave 73% yield vs. H2SO4, which gave 75% yield at 2.5 mol equiv). The use of polar nonparticipating solvents during the reaction had little impact on δ‐lactone formation or δ/γ ratio. Higher perchoric acid concentrations provided higher δ‐lactone yields with δ/γ ratios remaining nearly constant. The effect of sulfuric acid on δ‐lactone yield and δ/γ ratio was more direct; higher acid concentration improved, both. Both crystallization and short path distillation improved δ‐lactone quality but short path distillation gave, higher recovered yields. The δ‐lactones were converted to their corresponding 5‐hydroxy acids in the same reaction vessel, separated, and cyclized back to δ‐lactones upon heating under vacuum. This provided a convenient method for δ‐lactone purification.
Optimizing reaction parameters for the enzymatic synthesis of epoxidized oleic acid with oat seed peroxygenase
Authors: Piazza George J. , Foglia Thomas A. , Nuñez Alberto 
Published: November 2006

AbstractPeroxygenase is a plant enzyme that catalyzes the oxidation of a double bond to an epoxide in a stereospecific and enantiofacially selective manner. A microsomal fraction containing peroxygenase was prepared from oat (Avena sativa) seeds and the enzyme immobilized onto a hydrophobic membrane. The enzymatic activity of the immobilized preparation was assayed in 1 h by measuring epoxidation of sodium oleate (5 mg) in buffer‐surfactant mixtures. The pH optimum of the reaction was 7.5 when t‐butyl hydroperoxide was the oxidant and 5.5 when hydrogen peroxide was the oxidant. With t‐butyl hydroperoxide as oxidant the immobilized enzyme showed increasing activity to 65°C. The temperature profile with hydrogen peroxide was flatter, although activity was also retained to 65°C. In 1 h reactions at 25°C at their respective optimal pH values, t‐butyl hydroperoxide and hydrogen peroxide promoted epoxide formation at the same rate. Larger‐scale reactions were conducted using a 20‐fold increase in sodium oleate (to 100 mg). Reaction time was lengthened to 24 h. At optimized levels of t‐butyl hydroperoxide 80% conversion to epoxide was achieved. With hydrogen peroxide only a 33% yield of epoxide was obtained, which indicates that hydrogen peroxide may deactivate peroxygenase.