bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of phospholipids highly enriched with n‐3 polyunsaturated fatty acids by lipase
Authors: Haraldsson Gudmundur G. , Thorarensen Atli 
Published: May 2007

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

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

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

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

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

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

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

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

AbstractVegetable oils are often thermally polymerized to provide a vehicle for printing inks and paints. The formations of isomerization, and the intra‐ and intermolecular bonds involved in the thermal process are crucial in designing a product with the appropriate characteristics. It was found, with a differential scanning calorimeter, that the thermal polymerization of various vegetable oils could be activated at lower temperatures under a dry‐air purge and/or in the presence of metallic catalysts. The Diels‐Alder reaction and the formation of intermolecular bonds in alkali‐refined soybean oil under a dry‐air purge could be activated at 99 and 161°C in the presence of metallic catalysts, compared with 231 and over 300°C in the absence of metallic catalysts, respectively. The energies needed to activate the Diels‐Alder reaction and to form intermolecular bonds were calculated, and is in good agreement with available data. The hardness test of baked vegetable‐oil systems was also implemented to qualitatively determine the degree of cross‐linking.
Use of 13C nuclear magnetic resonance distortionless enhancement by polarization transfer pulse sequence and multivariate analysis to discriminate olive oil cultivars
Authors: Vlahov Giovanna , Shaw Adrian D. , Kell Douglas B. 
Published: May 2007

AbstractDistortionless enhancement by polarization transfer (DEPT) pulse sequence was used to set up a quantitative high‐resolution 13C nuclear magnetic resonance (NMR) method to discriminate olive oils by cultivars and geographical origin. DEPT pulse sequence enhances the intensity of NMR signals from nuclei of low magnetogyric ratio. The nuclear spin polarization is transferred from spins with large Boltzmann population differences (usually protons) to nuclear species characterized by low Boltzmann factors, e.g., 13C. The signal enhancement of 13C spectra ensures the accuracy of resonance integration, which is a major task when the resonance intensities of different spectra must be compared. The resonances of triglyceride acyl chains Cn:0, C18:1, C18:2, and C18:3, were also assigned. Multivariate analysis was carried out on the 35 carbon signals obtained. By using variable reduction techniques, coupled with standard statistical methods—partial least squares and principal components analysis—it was largely possible to separate the samples according to their variety and region of origin. With one problem variety removed, 100% prediction of the three remaining varieties was achieved. Similarly, by using the three regions with greatest representation in the data, all but one of a test set of 34 samples were correctly predicted. Thus, the composition of olive oils from different cultivars and of different geographical origin were compared and successfully studied by multivariate analysis. These considerations in conjunction with the structural elucidations of triglyceride molecules demonstrated that 13C NMR is among the most powerful techniques yet described for analysis of olive oils.
Temperature and cultivar effects on soybean seed oil and protein concentrations
Authors: Piper Ernest L. , Boote Kenneth I. 
Published: May 2007

AbstractThe soybean [Glycine max (L.) Merr.] industry is interested in cultivar and climate effects on seed composition. These factors may underlie the known geographic variation in seed protein and oil concentrations. Regression analyses were used to test hypotheses of the effect of temperature and cultivar on oil and protein concentrations of soybean seed using a large data set from the U.S.A. Soybean Uniform Tests. The data set included 20 cultivars representing 10 maturity groups across 60 locations (latitude 29.4 to 47.5° N) for a total of 1863 cultivar by location by year observations. Temperature was determined for each observation as the average daily mean temperature from predicted first pod (first pod at least 5 mm long), using the SOYGRO phenology model, to observed maturity. The mean temperature ranged from 14.6 to 28.7°C among the observations. Linear, quadratic, and linear plateau regression models of oil and protein concentrations vs. temperature were evaluated. The quadratic model gave the best‐adjusted R2 values for oil and protein with temperature, of 0.239 and 0.003, respectively. The analyses showed that the oil concentration increased with increasing temperature and approached a maximum at a mean temperature of 28°C. Unaccounted variation in the protein concentration may be from other factors such as photoperiod, water stress, or high temperatures during seed fill. Protein plus oil had a linear relationship with temperature (adjusted partial R2=0.183). These data document the contribution of climate and cultivar to geographic variability of oil and protein concentrations in the United States.
Deacidification of high‐acid rice bran oil by reesterification with monoglyceride
Authors: De B. K. , Bhattacharyya D. K. 
Published: May 2007

AbstractAutocatalytic esterification of free fatty acids (FFA) in rice bran oil (RBO) containing high FFA (9.5 to 35.0% w/w) was examined at a high temperature (210°C) and under low pressure (10 mm Hg). The study was conducted to determine the effectiveness of monoglyceride in esterifying the FFA of RBO. The study showed that monoglycerides can reduce the FFA level of degummed, dewaxed, and bleached RBO to an acceptable level (0.5±0.10 to 3.5±0.19% w/w) depending on the FFA content of the crude oil. This allows RBO to be alkali refined, bleached, and deodorized or simply deodorized after monoglyceride treatment to obtain a good quality oil. The color of the refined oil is dependent upon the color of the crude oil used.
Evaluation of surfactant‐aided degumming of vegetable oils by membrane technology
Authors: Subramanian R. , Nakajima M. , Yasui A. , Nabetani H. , Kimura T. , Maekawa T. 
Published: May 2007

AbstractThe first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low‐grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant‐aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.
Storage stability of potato chips fried in genetically modified canola oils
Authors: Petukhov I. , Malcolmson L. J. , Przybylski R. , Armstrong L. 
Published: May 2007

AbstractThe storage stability of potato chips fried in regular (RCO), hydrogenated (HYCO), low‐linolenic (LLCO), and high‐oleic (HOCO) canola oils was compared. Potato chips were fried in each oil over a 5‐d period for a total of 40 h of frying. Chips from frying day 1 and 5 were packaged and stored at 60°C for 0, 1, 2, 4, 8, and 16 d. Lipids were extracted from the stored chips and analyzed for peroxide values, free fatty acids (FFA), conjugated dienoic acids (CDA), and polar components. A trained sensory panel evaluated the stored chips for odors characteristic of oxidation. Chips were also analyzed for volatile components. Potato chips fried in RCO, LLCO and HOCO developed an intense painty odor, whereas chips fried in HYCO developed an intense stale/musty odor by the end of the 16 d of storage. Chips fried in RCO had greater rates of accumulation of peroxides, FFA, CDA, and polar components and developed higher levels of total volatiles over the 16 d of storage than chips fried in the other three oils. Chips fried in HYCO had lower rates of accumulation of peroxides and CDA than chips fried in LLCO and HOCO, and lower rates of FFA accumulation than chips fried in LLCO. Chips fried in HYCO and HOCO had the lowest amounts of total volatiles during storage. The effect of oil degradation products on potato chip storage stability was not shown in this study since only the chips fried in HYCO from frying day 5 exhibited a significantly greater rate of off‐odor development than chips from frying day 1, and only the chips fried in LLCO from frying day 5 had a greater rate of accumulation of volatiles than chips from frying day 1.
Kinetic model for autoxidation of β‐carotene in organic solutions
Authors: Takahashi Atsushi , Shibasaki‐Kitakawa Naomi , Yonemoto Toshikuni 
Published: May 2007

AbstractAutoxidation of β‐carotene was studied experimentally using n‐decane as a solvent under various reaction conditions of temperature and dissolved oxygen concentration A novel kinetic model was proposed on the basis of an autocatalytic free‐radical chain reaction mechanism. A secondary initiation reaction by decomposition of hydroperoxide and reactions concerned with a β‐carotene‐derived C‐centered radical in propagation and termination processes were taken into consideration in the model. There were four unknown kinetic constants, and the constants were estimated by fitting the model with the experimental data. The fitted results are in good agreement with the experimental data in all stages of the kinetics of autoxidation and over a wide range of oxygen concentrations. The model described not only the appearance of the induction stage but also the effect of the oxygen concentration on the autoxidation rate. In addition, the model predicted the behavior of autoxidation in another solvent at low temperature that had been reported by other researchers.
Antioxidant synergy of α‐tocopherol and phospholipids
Authors: Bandarra Narcisa M. , Campos Regina M. , Batista Irineu , Nunes M. Leonor , Empis José M. 
Published: May 2007

AbstractThe prevention of oxidation of a refined sardine oil by α‐tocopherol at 0.04%, by several phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cardiolipin (CL)] at 0.5%, as well as by combinations of α‐tocopherol with each phospholipid, was investigated. The evolution of the oxidation process during 1 mon at 40±2°C was followed by a series of methods, measuring peroxide value (PV), diene, triene, and polyene index, and absorbance at 430 nm, while α‐tocopherol and phospholipid content were being monitoried. Among these indices, PV was found to be the most adequate to follow the process. PC was the most effective individual antioxidant as shown by the PV values obtained at the end of the storage period, which were 54.0, 83.4, 87.9, and 97.7 meq O2/kg for PC, CL, PE, and α‐tocopherol, respectively. The highest synergistic effect was obtained with a mixture of α‐tocopherol and PE, and the second and third best by mixtures made with PC and CL, respectively. The corresponding PV values recorded at the end of the period were 27.0, 35.0, and 58.0 meq O2/kg. The high degree of synergy between PE and tocopherol is probably due to the occurrence of a simultaneous antioxidant mechanism involving Maillard compounds.
Tocopherol distribution and oxidative stability of oils prepared from the hypocotyl of soybeans roasted in a microwave oven
Authors: Yoshida Hiromi , Takagi Sachiko , Mitsuhashi Sayaka 
Published: May 2007

AbstractWhole soybeans (Glycin max L.) were roasted by exposure to microwaves at a frequency of 2,450 MHz, and their hypocotyls were separated from other tissues (seed coat and cotyledons). The quality characteristics and composition in the hypocotyl oils were studied in relation to their tocopherol distributions and were evaluated as compared to an unroasted oil sample. Only minor increases (P<0.05) in chemical and physical changes of the oils, such as carbonyl value, anisidine value and color development, occurred with increased roasting time. Significant decreases (P<0.05) were observed in the amounts of phospholipids in the oils after microwave roasting. Nevertheless, compared to the original level, more than 80% tocopherols still remained after 20 min of roasting. These results suggest that the exposure of soybeans to microwaves for 6 to 8 min caused no significant loss or changes in the content of tocopherols and polyunsaturated fatty acids in the hypocotyls. Therefore, a domestic microwave oven would be useful as a simple and quick means for preparing hypocotyl oil of good quality.