bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethyl esters from the single‐phase base‐catalyzed ethanolysis of vegetable oils
Authors: Zhou Weiyang , Konar Samir K. , Boocock David G. B. 
Published: November 2006

AbstractThe effects of alcohol/oil molar ratio, base concentration, and temperature on the single‐phase base‐catalyzed ethanolyses of sunflower and canola oils were determined. The use of tetrahydrofuran as co‐solvent, as well as higher than usual alcohol/substrate molar ratios, prevented glycerol separation. This allowed each reaction to reach equilibrium rather than just steady‐state conditions. High conversions of oil lowered the concentrations of MG and DG surfactants in the products, and thereby mitigated the formation of emulsions usually associated with ethanolysis reactions. An alcohol/oil molar ratio of 25∶1, together with the necessary amount of cosolvent, gave optimal results. At this molar ratio, despite equilibrium being achieved, ethanolysis, unlike methanolysis, did not quite produce biodiesel‐standard material, the MG content being approximately 1.5 mass%. For methanolysis and 1‐butanolysis, the corresponding values were 0.6 and 2.0 mass%, respectively. The use of 1.4 mass% KOH (equivalent to 1.0 mass% NaOH) led to ethanolysis equilibrium within 6–7 min at 23°C rather than 15 min when only 1.0 mass% was used. At 60°C, equilibrium was reached within only 2 min. Soybean and canola oils behaved the same.
Oil production from catfish viscera
Authors: Sathivel Subramaniam , Prinyawiwatkul Witoon , King Joan M. , Grimm Casey C. , Lloyd Steven 
Published: November 2006

AbstractOil was extracted from catfish viscera and purified (degummed, neutralized, bleached, and deodorized). The yield of catfish oil after purification was 65.7%. The major yield loss took place during the degumming process. The FA found in crude catfish visceral oil were 14∶0, 16∶0, 16∶1, 18∶0, 18∶1, 18∶2, 18∶3, 20∶0, 20∶1, 20∶2, 20∶3, 20∶4, and 22∶6, the predominant FA being 18∶1, 16∶0, 18∶2, and 18∶0. The total unsaturated FA in the purified catfish oil amounted to 67.7%. The combined n−3 FA content of the purified catfish oil was 4.6 mg/g of oil. The purified catfish oil contained 1.21 mg/g DHA. FFA, water activity, and some mineral contents decreased during purification. Bleaching removed pigments, thus resulting in oil with greater lightness and less yellowness.
Cyclic FA monomers in high‐oleic acid sunflower oil and extra virgin olive oil used in repeated frying of fresh potatoes
Authors: Romero A. , Cuesta C. , Sánchez‐Muniz F. J. 
Published: November 2006

AbstractThe measurement of FA profile, polar material, oligomers, oxidized triacylglycerols (OTG), total polyphenols, and cyclic FA monomers (CFAM) was used to evaluate the alteration of a high‐oleic sunflower oil (HOSO) and an extra virgin olive oil (EVOO) used in 75 domestic fryings of fresh potatoes with frequent replenishment (FR) of unused oil. CFAM were absent in the unused EVOO but appeared in small amounts in the unused HOSO. Although polar material, oligomers, OTG, and CTAM contents increased and linoleic acid and polyphenols content decreased in both oils during repeated frying, the changes produced should be considered small and related to the use of very stable oils and FR. Throughout the 75 fryings, the total CFAM concentration was higher in HOSO than in EVOO. OTG increased more quickly in EVOO, whereas oligomers increased more quickly in HOSO. Polar material and oligomer content appear significantly correlated (r=0.9678 and r=0.9739, respectively; for both, P<0.001) with the CFAM content. A 25% polar material and 12% oligomer content would correspond to about 1 mg·kg−1 oil of CFAM. Data suggest that both oils, particularly EVOO, perform very well in frying, with a low production of oligomers, polar materials, and CFAM.
Genetic diversity for lipid content and fatty acid profile in rice bran
Authors: Goffman Fernando D. , Pinson Shannon , Bergman Christine 
Published: November 2006

AbstractRice (Oryza sativa L.) bran contains valuable nutritional constituents, which include lipids with health benefits. A germplasm collection consisting of 204 genetically diverse rice accessions was grown under field conditions and evaluated for total oil content and fatty acid (FA) composition. Genotype effects were highly statistically significant for lipid content and FA profile (P<0.001). Environment (year) significantly affected oil content (P<0.05), as well as stearic, oleic, linoleic, and linolenic acids (all with P<0.01 or lower), but not palmitic acid. The oil content in rice bran varied relatively strongly, ranging from 17.3 to 27.4% (w/w). The major FA in bran oil were palmitic, oleic, and linoleic acids, which were in the ranges of 13.9–22.1, 35.9–49.2, and 27.3–41.0%, respectively. The ratio of saturated to unsaturated FA (S/U ratio) was highly related to the palmitic acid content (r2=0.97). Japonica lines were characterized by a low palmitic acid content and S/U ratio, whereas Indica lines showed a high palmitic acid content and a high S/U ratio. The variation found suggests it is possible to select for both oil content and FA profile in rice bran.
Contribution of FA profile obtained by high‐resolution GC/chemometric techniques to the authenticity of green and roasted coffee varieties
Authors: Rui Alves M. , Casal S. , Oliveira M. B. P. P. , Ferreira M. A. 
Published: November 2006

AbstractTwenty‐four coffee samples of different botanical and geographical origins were analyzed for their FA composition, including trans isomers. The analysis used high‐resolution GC/FID/CP Sil 88 capillary column to separate FAME obtained by esterification with BF3/methanol. The purpose of this work was to verify whether this parameter could be applied in the discrimination of arabica and robusta coffees, either in green or in roasted stage. Statistical approaches were applied to check the efficiecies of some univariate and multivariate procedures, and the results permitted the conclusion that the FA profile can be used as a coffee variety marker and may inform on the historical background, mainly in terms of heat‐processing conditions.
Enzymatic kinetic resolution of secondary alcohols by esterification with FA under vacuum
Authors: Irimescu Roxana , Saito Takao , Kato Katsuya 
Published: November 2006

AbstractKinetic resolution of some chiral secondary alcohols [2‐octanol, 1‐phenylethanol, and 1‐(2‐naphthyl)ethanol] with high enantioselectivity (E>300) was achieved by direct esterification with FFA catalyzed by immobilized Candida antarctica B lipase. The reaction equilibrium was shifted toward the synthetic side by the removal of the water formed under vacuum. Esterification of rac‐2‐octanol at an alcohol/FFA molar ratio of 2∶1 was used as a model reaction. The chain length of FFA and their structure influenced the reaction rate but did not have a measureable effect on E. The best acyl donor was decanoic acid: >47% conversion at 4 h with virtually perfect E. Temperature did not affect E in the range studied (15–45°C), but temperatures at the higher end afforded improved reaction rates. The reaction rates and E were compared for three different acyl donors. The initial reaction rate increased in the following order: ethyl laurate < lauric acid < vinyl acetate. E was high (E>300) for all acyl donors. Racemic 1‐phenylethanol and 1‐(2‐naphthyl)ethanol were also resolved by direct esterification with decanoic acid in short times (3 and 4 h, respectively) with E>300 and excellent conversions. Preparative‐scale kinetic resolution of 2‐octanol was also performed.
The influence of antioxidants on the oxidation stability of biodiesel
Authors: Mittelbach Martin , Schober Sigurd 
Published: November 2006

AbstractOxidation stability of bodiesel is an important issue because FA derivatives are more sensitive to oxidative degradation than mineral fuel. Therefore, in the most recent European Specifications for biodiesel, a minimum value of 6 h for the induction period at 110°C, measured with a Rancimat instrument, is specified. To guarantee this value at the filling station, the use of additional antioxidants will be necessary. In this paper we show the influence of different synthetic and natural antioxidants on the oxidation stability, using the specified test method. Biodiesel produced from rapeseed oil, sunflower oil, used frying oil, and beef tallow, both undistilled and distilled, was investigated. The four synthetic antioxidants pyrogallol (PY), propylgallate (PG), TBHQ, and BHA produced the greatest enhancement of the induction period. These four compounds and the widely used BHT were selected for further studies at concentrations from 100 to 1000 mg/kg. The induction periods of methyl esters from rapeseed, oil, used frying oil, and tallow could be improved significantly with PY, PG, and TBHQ, whereas BHT was not very effective. A good correlation was found between the improvement of the oxidation stability and the FA composition.
Lipase‐catalyzed interesterification reaction between menhaden oil and the ethyl ester of CLA: Uniresponse kinetics
Authors: Torres Carlos F. , Lin Betty , Lessard Louis P. , Hill Charles G. 
Published: November 2006

AbstractThe kinetics of the interesterification reaction between menhaden oil and the ethyl ester of CLA (CLAEE) in the presence of an immobilized lipase from Rhizomucor miehei was investigated. A 23 factorial design with a central point was used to define the experimental region. The factors considered were the molar ratio of reactants, the enzyme loading, and the temperature. Optimal results were obtained when the reaction was carried out at 55°C with an enzyme loading of 0.65 g per 12 g mixture and a mole ratio of CLAEE to menhaden oil equal to 0.13. A uniresponse kinetic model of the Michaelis‐Menten type was developed to characterize the rate of consumption of CLAEE and the rate of release of FA ethyl esters from menhaden oil. The best fit of the data with a uniresponse model was obtained using a form based on reversible reactions and inhibition by the ethyl esters of the FA residues released by the reaction.
Chemical and sensory properties of gas‐purged, minimum‐refined, extruded‐expelled soybean oil
Authors: Wang Xi , Wang Tong , Johnson Lawrence A. 
Published: November 2006

AbstractDeveloping low‐cost oil refining methods is critical to business that use low‐cost extrusion‐expelling (E‐E) to crush soybeans so they can capture the full value‐added potential by marketing finished oils. Normal commodity (CO) and high‐oleic (HO) E‐E soybean oils were minimum‐refined, gas‐purged, and evaluated in frying applications. Degummed commodity oil (DCO) and minimum‐refined (degummed and deacidified by Magnesol® adsorption) CO and HO oils were gas‐purged with N2 for 1 h at 150°C. For DCO, gas purging did not affect PV, oxidative stability index (OSI), FFA, color, and total tocopherol content, but p‐anisidine value (AV) increased. For CO, the minimum‐refined, gas‐purged oil did not differ from degummed, gas‐purged oil in terms of p‐AV, OSI, tocopherol content, and color. PV and FFA were lower in minimum‐refined, gas‐purged oil. Minimum‐refined, gas‐purged HO had much higher OSI, tocopherol, and FFA levels than did minimum‐refined, gas‐purged CO. The oils were used to fry bread cubes at 185°C. Fried bread cubes were stored under various conditions and evaluated for flavor attributes. These oils were different in toasty/nutty, beany/grassy, and oxidized flavors, as well as overall flavor intensity and desirability. Minimum‐refined, gas‐purged oils produced fried bread cubes having initial flavor profiles similar to those fried in commercial oil; however, when fresh oils were used they were less stable to oxidation. Longer heating times of the minimum‐refined, gas‐purged oils produced bread cubes with better oxidative stabilities than those produced with commercial oil.
Ozonation of sunflower oil: Spectroscopic monitoring of the degree of unsaturation
Authors: Soriano Nestor U. , Migo Veronica P. , Matsumura Masatoshi 
Published: November 2006

AbstractConsumption of ozone by unsaturated FA moieties of sunflower oil (SFO) was monitored by 1H NMR and FTIR spectroscopy. Degradation of linoleate was found to be 1.5 and 1.8 times higher than oleate when SFO was ozonized in the absence and presence of water, respectively. Products of ozonation in both cases include aldehydes and ozonides with 1,2,4‐trioxolane ring. Hydroxyl‐containing compounds, which could be carboxylic acids and/or hydroperoxides, were also detected in samples ozonized in the presence of water. The extent of ozonation had very little effect on the aldehyde/ozonide ratio obtained from NMR spectra, especially in the ozonation of neast SFO. The aldehyde/ozonide ratios obtained regardless of the extent of ozonation were 10.5:89.5 and 46.6:53.4 for SFO ozonized in the absence and presence of water, respectively.
Preparation of long‐chain β‐enaminones and β‐diketones from long‐chain 3,5‐disubstituted isoxazole compounds
Authors: Kenar James A. 
Published: November 2006

AbstractA series of long‐chain compounds containing the β‐enaminone functionality were prepared in yields ranging from 71 to 88% from their corresponding long‐chain 3,5‐disubstituted isoxazole precursors utilizing a Raney nickel‐catalyzed reductive ring‐opening procedure. These newly prepared multifunctional compounds were subsequently hydrolyzed under mild acidic conditions (pH 4–5) to give their corresponding long‐chain β‐diketones in yields ranging from 79 to 98%. Both the β‐enaminone and β‐diketone functionalized compounds were characterized by NMR, IR spectroscopy, GC‐MS, and m.p. The mass spectra for these two classes of compounds, derived by utilizing electron impact ionization, gave distinctive McLafferty rearrangement fragmentation ions that clearly established the newly introduced functionality to reside at the C‐2 and C‐4 positions of the lipid’s alkyl chain. 1H NMR spectra of the pure β‐diketone compounds were complex owing to the keto enol tautomerism displayed by the β‐diketone moiety. In solution the β‐diketone compounds were shown to exist mainly in the enolic tautomeric form. Long‐chain β‐diketone compounds are known to be relatively common constituents of some plant waxes, and the overall procedure starting from soybean methyl esters provides a complementary approach to prepare these types of compounds.
Determination of nonvolatile components in polar fractions of rice bran oils
Authors: Abidi S. L. , Rennick K. A. 
Published: November 2006

AbstractHigh‐oryzanol rice brain oil (HORBO), rice bran oil (RBO), and partially hydrogenated soybean oil (PHSBO) were used to prepare french fries. Polar fractions of the three oils were analyzed for nonvolatile components by high‐performance size‐exclusion chromatography (HPSEC) with ELSD. In all frying experiments, both HORBO and RBO yielded predominantly dimeric and monomeric materials. The concentrations of polymeric species in HORBO and RBO were greater than in PHSBO. The major degradation products from HORBO, RBO, and PHSBO were dimers (8.93 mg/100 mg oil), monomers (10.5 mg/100 mg oil), and DG (22.4 mg/100 mg oil), respectively. Thermal degradation via hydrolysis was much greater in PHSBO than in HORBO or RBO. Distribution data indicated that the extent of polymer formation from frying was in the order RBO>HORBO >PHSBO, consistent with the degree of lipid unsaturation and the oryzanol content in these oils. HPSEC‐ELSD results from the two RBO showed that the amounts of various polymeric species, including trimers and higher polymers, were lower in HORBO than in RBO. The percentage of polar materials and the percentage of polymerized TG, which were used as indicators of oil quality and stability, decreased with increasing tocopherol and oryzanol contents in the order PHSBO>HORBO>RBO.
Immobilization of Candida rugosa lipase by sol‐gel entrapment and its application in the hydrolysis of soybean oil
Authors: Noureddini H. , Gao X. , Joshi S. 
Published: November 2006

AbstractImmobilization of lipase AY from Candida rugosa by entrapment within a chemically inert hydrophobic sol‐gel support was studied. The gel‐entrapped lipase was prepared by polycondensation of hydrolyzed tetramethoxysilane and isobutyltrimethoxysilane. Certain modifications were incorporated into the conventional immobilization procedure, including the use of glucose as additive and the application of vacuum during the drying and aging stages. The activity and thermostability of immobilized enzyme were subsequently determined in hydrolyzing soybean oil. Hydrolysis results showed more than 95 mol% of the theoretical yield for the formation of FF after 1 h of reaction at 40°C. The level of FFA was 3.3 times greater than that seen when an immobilized enzyme was prepared by the conventional sol‐gel process. The immobilized enzyme retained most of its hydrolytic activity compared to the free enzyme and kept more than 95% activity after 120 h of incubation at 40°C, whereas the free enzyme lost 67% of its activity after 24 h of incubation and almost all of its activity after 96 h of incubation at 40°C. The immobilized enzyme also proved to be very stable, as it retained more than 90% of the initial activity after 16 one‐hour reactions. Surface characterization studies suggested that the enzyme‐containing sol‐gel particles have amorphous morphology and are void of micro/meso pores.
Bioconversion of n−3 and n−6 PUFA by Clavibacter sp. ALA2
Authors: Hosokawa Masashi , Hou Ching T. , Weisleder Dave 
Published: November 2006

AbstractClavibacter sp. ALA2 oxidized n−3 and n−6 PUFA into a variety of oxylipins. Structures of products converted from EPA and DHA were determined as 15,18‐dihydroxy‐14,17‐epoxy‐5(Z),8(Z),11(Z)‐eicosatrienoic acid and 17,20‐dihydroxy‐16,19‐epoxy‐4(Z),7(Z),10(Z),13(Z)‐docosatetraenoic acid by GC‐MS and NMR analyses. In contrast, γ‐linolenic acid and arachidonic acid were converted to diepoxy bicyclic FA, tetrahydrofuranyl monohydroxy FA, and trihydroxy FA. Thus, the structures of bioconversion products were different between n−3 and n−6 PUFA. Furthermore, strain ALA2 placed hydroxy groups and cyclic structures at the same position from the ω‐terminal despite the number of carbons in the chain and the double bonds in the PUFA.
Oleic acid content in ground corn by NIR spectroscopy with an indirect calibration method
Authors: Wright Steve , Hagen Lisa 
Published: November 2006

AbstractDeveloping corn hybrids with improved FA profiles is important in providing products with enhanced nutritional characteristics. To support this effort, rapid screening methods are needed to track the various traits of interest. In using NIR methods, calibrations are based on an assumed linear relationship between the concentration of the analyte of interest and the absorbance of the sample. Although this point seems obvious, this linear relationship does not exist when using GC analysis as a reference method for oleic acid content in ground corn kernels. In this case, the GC data provide a relative oleic acid content of the oil and not of the grain from which the NIR spectrum is measured. A method of removing this nonlinearity by modeling the absolute oleic acid content in the grain has been developed. The relative oleic acid content of the oil is then calculated from this predicted absolute oleic acid value, and the total oil content of the grain is predicted from another calibration model. Significant improvement in the model's predictive ability is demonstrated using this two‐calibration model.
Comparison of kjeldahl and dumas methods for determining protein contents of soybean products
Authors: Jung S. , Rickert D. A. , Deak N. A. , Aldin E. D. , Recknor J. , Johnson L. A. , Murphy P. A. 
Published: November 2006

AbstractThe Kjeldahl and Dumas methods for quantifying nitrogen content were compared using nine soybean products having protein contents ranging from 0.5 to 90%. In addition to comparing day‐to‐day variability of the Dumas method, differences between and variabilities of two Kjeldahl systems and Kjeldahl operators were also evaluated. The Kjeldahl method gave slightly, but significantly, lower values than did the Dumas method. Both the Kjeldahl and Dumas methods had equivalent variabilities (same SD about the means). The ratios between the means for the Kjeldahl and Dumas (K/D) protein values ranged from 0.66 to 1.03. The conversion equation y=−0.00536+0.97188x (R2=0.9997) was developed and validated to convert from Dumas to kjeldahl protein concentrations.
Relative FFA formation and lipid oxidation of commercially milled unseparated, head, and broken rice
Authors: Monsoor Mamun A. , Proctor Andrew 
Published: November 2006

AbstractThis study was conducted to determine the relative rate of FFA formation and lipid oxidation of unseparated (head and broken), head, and broken rice and the effect of water washing on the lipid quality of broken rice. A regression model was developed with surface FFA or conjugated diene (CD) content vs. incubation time to determine the rates of FFA formation and lipid oxidation. The surface lipid contents of unseparated, head, and broken rice were 0.40, 0.38, and 0.50% of rice, respectively. FFA formation during storage showed three phases: an initial rapid formation, followed by a period of very little or no formation, and finally a phase of gradual formation. In contrast, CD formation initially showed a slow increase but later increased gradually with storage time. The relative rates of FFA and CD formation of unseparated, head, and broken rice were 0.0028, 0.0027, and 0.0036 and 0.192, 0.188, and 0.377, respectively. Water washing reduced the rates of FFA formation and lipid oxidation of broken rice to 0.0015 and 0.2192 from initial values of 0.0031 and 0.369, respectively. Water washing appears to be a simple and practical means of lowering the rates of FFA formation and lipid oxidation in broken rice.
Pigment parameters determining spanish virgin olive oil authenticity: Stability during storage
Authors: Roca María , Gandul‐Rojas Beatriz , Gallardo‐Guerrero Lourdes , Mínguez‐Mosquera M. Isabel 
Published: November 2006

AbstractThe chlorophyll and carotenoid pigment composition in 12 mono‐variety virgin olive oils was examined every 30 d during 1 yr of storage at 15°C in darkness. The oil authenticity parameters, as defined by the ratio of chlorophylls/carotenoids and the ratio of minor carotenoids/lutein, remained stable throughout storage, irrespective of the variety and degree of ripeness of the source fruit. The percent of violaxanthin, percent of lutein, and total pigment content, the classifying variables chosen as the best possible discriminators among olive varieties, also remained stable during storage. The prediction model for olive variety, which was based on a discriminant multivariate analysis of the observed values of these variables, gave a correct classification in 99.6% of the oils analyzed. The discriminant criterion established remained valid after 1 yr of oil storage. The detection of chlorophyll derivatives other than those associated with the physical extraction process was seen as a quality index, as small, analytically detectable transformations in the structure of pigments were indicative of oil storage.
A rigorous kinetic model for β‐carotene oxidation in the presence of an antioxidant, α‐tocopherol
Authors: Takahashi Atsushi , Shibasaki‐Kitakawa Naomi , Yonemoto Toshikuni 
Published: November 2006

AbstractOxidation of β‐carotene in an inert solvent, n‐decane, in the presence of various concentrations of the antioxidant α‐tocopherol was studied. The progress of carotene oxidation was suppressed as long as the tocopherol remained in the system. A rigorous kinetic model for carotene oxidation in the presence of an antioxidant was proposed based on a reaction mechanism in which not only the antioxidation but also the co‐oxidation and radical‐exchange reaction of tocopherol with carotene were incorporated. The model quantitatively described the oxidation behavior of carotene over a wide range of temperatures, oxygen compositions, and initial antioxidant concentrations.