bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protection of α‐tocopherol in nonpurified and purified fish oil
Authors: Kul Elin , Ackman Robert G. 
Published: November 2006

AbstractMenhanden oil was purified by column chromatography to remove minor components. The effect of α‐tocopherol (α TOH) (50–500 ppm) on the rate of formation of hydroperoxides in the original menahaden oil and in the purified menhaden triacylglycerol (TAG) fraction was studied at 30°C in the dark. An increase in the initial rate of formation of hydroper‐oxides was observed at αTOH concentrations above 100 ppm in both substrates. The original menhaden oil oxidized more rapidly than the purified menhaden, TAG at all antioxidant levels tested, and the presence of minor components in the menhaden oil was found to contribute only to a limited extent to the peroxidizing effect of αTOH. The αTOH did not display any prooxidant activity at either of the concentrations tested when the control oil was the purified menhaden TAG. Addition of ascorbyl palmitate eliminated the initial peroxidizing effect of αTOH, and this emphasizes the participation of the α‐toco‐pheroxyl radical in the reactions causing an accumulation of hydroperoxides at high concentrations of αTOH.
Antioxidant capacity of extra‐virgin olive oils
Authors: Ninfali Paolino , Aluigi Gianfranca , Bacchiocca Mara , Magnani Mauro 
Published: November 2006

AbstractIn this study, the oxygen radical absorbance capacity (ORAC) of vegetable oils was investigated using a spectrofluorometric method, which measures the protection of the phenolic substances of the oil on the β‐phycoerythrin fluorescence decay in comparison with Trolox. More than 97% of the phenolic substances was extracted from the oil using methanol, and the methanolic extract was then used for the ORAC and the total phenolics assay. We found a significant correlation between ORAC values of different olive oils and the total amount of phenolics. For extra‐virgin olive oils, maximal ORAC values reached 6.20±0.31 μmol Trolox equivalent/g, while refined and seed oils showed values in the 1–1.5 μmol Trolox equivalent/g range. Our method is useful to assess the quality of olive oils and to predict, in combination with the rancidity tests, their stability against oxidation.
Reproducibility of the bromthymol blue standards used for color specification of virgin olive oil
Authors: Melgosa M. , Prez M. M. , Hita E. , Heredia F. J. , Alba J. , Moyano M. J. 
Published: November 2006

AbstractThree replicates were prepared for each of 60 BTB (bromthymol blue) standards, which are usually employed to determine the color of virgin olive and seed oils, and their colors were measured by spectrophotometric and spectroradiometric techniques on a monthly basis over a year. Although in principle both techniques are valid, their results are weakly correlated. The major color change of the BTB standards occurred soon after sample preparation; after 5 mon, the color stabilized at approximately 3.0 Commission Internationale de l’Éclairage 1976‐(L*a*b*) (CIELAB) units, with respect to the initial values. Therefore, after preparation, a certain waiting period would be advisable before using the BTB standards. The color of the BTB standards changes over time in the sense of becoming lighter, more saturated, and less greenish. In the monthly periods after the fifth month, the average color change of the BTB standards was negligible, being slightly lower than the average variability of the three replicates (which is around 1.5 CIELAB units).
Utilization of reaction medium‐dependent regiospecificity of Candida antarctica lipase (Novozym 435) for the synthesis of 1,3‐dicapryloyl‐2‐docosahexaenoyl (or eicosapentaenoyl) glycerol
Authors: Irimescu Roxana , Furihata Kiyomi , Hata Kazuhiko , Iwasaki Yugo , Yamane Tsuneo 
Published: November 2006

AbstractA highly efficient enzymatic method for the synthesis of regioisomerically pure 1,3‐dicapryloyl‐2‐docosahexaenoyl glycerol (CDC) in two steps was established. 2‐Monoglyceride (2‐MG) formation by ethanolysis of tridocosahexaenoylglycerol (DDD) with immobilized Candida antarctica lipase (Novozym 435) as catalyst was the key step of the synthesis. CDC was finally obtained by reesterification of 2‐MG with ethylcaprylate (EtC) catalyzed by Rhizomucor miehei lipase (Lipozyme IM). The regiospecificity of Novozym 435 depended on the type of reaction and the initial composition of the reaction medium. It displayed strict 1,3‐regiospecificity for ethanolysis at a high excess of ethanol in the reaction mixture although it displayed no regiospecificity in transesterification and esterification reactions. The highest yield of CDC (85.4%) was obtained by ethanolysis at a 4∶1 weight ratio of ethanol/DDD for 6 h followed by reesterification at a 20∶1 molar ratio of EtC/initial DDD for 1.5 h. The regioisomeric purity of CDC was 100%. Good results were obtained also for the synthesis of 1,3‐dicapryloyl‐eicosapentaenoylglycerol (CEC) by the same method: 84.2% yield and 99.8% regioisomeric purity at the same reactant ratios as above. The yield of the reesterification step and the regioisomeric purity of the product were influenced by the molar ratio of the reactants for both CDC and CEC syntheses: higher excess of EtC favored higher yields and regioisomeric purity of the products.
An electronic nose to classify Iberian pig fats with different fatty acid composition
Authors: Carrapiso Ana I. , Ventanas Jesús , Jurado Ángela , García Carmen 
Published: November 2006

AbstractFatty acid analysis is frequently performed in fat and other raw materials to classify them according to their fatty acid composition, but the need to carry out online determinations has generated a growing interest in more rapid options. This research was done to evaluate the ability of a polymer‐sensor based electronic nose to classify Iberian pig fat samples with different fatty acid compositions. Significant correlations were found between individual fatty acids and sensor responses, proving that sensor response data were not fortuitously sorted. Significant correlations also appeared between some sensors and water activity, which was considered during the sample classification. Two supervised pattern recognition techniques were attempted to process the sensor responses: 85.5% of the samples were correctly classified by discriminant analysis, but the percentage increased to 97.8% using a one‐hidden layer back‐propagation artificial neural network. The electronic nose (specifically, sensor responses analyzed by a neural network) achieved success similar to that obtained using the more usual fatty acid analysis by gas chromatography.
Polyunsaturated fatty acid concentrates from borage and linseed oil fatty acids
Authors: Chen Tor‐Chern , Ju Yi‐Hsu 
Published: November 2006

AbstractA modified low‐temperature solvent crystallization process was employed for the enrichment of polyunsaturated fatty acids (PUFA) in borage and linseed oil fatty acids. The effects of solvent, operation temperature, and solvent to free fatty acid (FFA) ratio on the concentration of PUFA were investigated. The best results were achieved when a mixture of 30% acetonitrile and 70% acetone was used as the solvent. With an operation temperature of −80°C and a solvent to FFA ratio of 30 mL/g, γ‐linolenic acid (GLA) in FFA of saponified borage oil can be raised from 23.4 to 88.9% with a yield of 62.0%. At a yield of 24.9%, α‐linolenic acid in linseed oil can be increased from 55.0 to 85.7%. The results of this work are comparable to the best results available in the literature.
Screening vegetable oil alcohol esters as fuel lubricity enhancers
Authors: Drown D. C. , Harper K. , Frame E. 
Published: November 2006

AbstractMethyl and ethyl monoalkyl esters of various vegetable oils were produced for determining the effects of type of alcohol and fatty acid profile of the vegetable oil on the lubricity of the ester. Four methyl esters and six ethyl esters were analyzed for wear properties using the American Society for Testing and Materials method D 6079, Evaluating Lubricity of Diesel Fuels by the High‐Frequency Reciprocating Rig. Ethyl esters showed noticeable improvement compared to methyl esters in the wear properties of each ester tested. No correlation was found between lubricity improvement and fatty acid profile of the ester, except that esters of castor oil had improved lubricity over other oils with similar carbon chain‐length (C18) fatty acids.
Antioxidant activities of major components of γ‐oryzanol from rice bran using a linoleic acid model
Authors: Xu Zhimin , Godber J. Samuel 
Published: November 2006

AbstractThe change in hydroperoxides of linoleic acid incubated with constant micro air flow at 37°C was used to evaluate the antioxidant activities of three major components of γ‐oryzanol from rice bran (cycloartenyl ferulate, 24‐methylene cycloartanyl ferulate, and campesteryl ferulate) compared with α‐tocopherol and ferulic acid. The four hydroperoxide isomers of linoleic acid, 9‐hydroperoxy‐10‐trans, 12‐cis‐octadecadienoic acid [9HPODE(t,c)], 9‐hydroperoxy‐10‐trans, 12‐trans‐octadecadienoic acid, 13‐hydroperoxy‐9‐cis, 11‐trans‐octadecadienoic acid [13HPODE(c,t)], and 13‐hydroperoxy‐9‐trans, 11‐trans‐octadecadienoic acid, were measured using normal‐phase high‐performance liquid chromatography with an ultraviolet detector. The three components of γ‐oryzanol evidenced significant antioxidant activity when they were mixed with linoleic acid in a molar ratio of 1∶100 and 1∶250 but not in a molar ratio of 1∶500 (P<0.05). α‐Tocopherol and ferulic acid also demonstrated significant antioxidant activity at all three molar ratios (P<0.05). The highest molar ratio (1∶100) of α‐tocopherol, however, caused greater levels of 9HPODE(t,c) and 13HPODE(c,t) than the other two less concentrated treatments.
Characterization of extruded‐expelled soybean flours
Authors: Crowe Troy W. , Johnson Lawrence A. , Wang Tong 
Published: November 2006

AbstractIn recent years there has been widespread growth in extruding‐expelling (E‐E) facilities for small‐scale processing of soybeans. To compete in a highly competitive market, these E‐E operations are looking for ways to optimize production of their oil and meal products for values to their customers. The objective of this study was to determine the ranges of residual oil contents and protein dispersibility indices (PDI) possible with E‐E processing of soybeans. We also characterized the partially defatted meal for other factors important in food and feed applications. Residual oil and PDI values ranged from 4.7 to 12.7% and 12.5 to 69.1%, respectively. E‐E conditions significantly influenced residual lipase, lipoxygenase (L1–L3), and trypsin inhibitor activities. Chemical compositions were different for whole, dehulled, and reduced‐moisture soybeans, with dehulled soybeans tending to produce meals having higher residual oil contents at higher PDI values. It was possible to process soybeans with different characteristics (e.g., moisture content, whole, dehulled) to produce meals and flours with wide ranges of properties, providing E‐E operators with opportunities to market value‐added products.
Enzymatic process for extracting oil and protein from rice bran
Authors: Hanmoungjai P. , Pyle D. L. , Niranjan K. 
Published: November 2006

AbstractEnzymatic extraction of oil and protein from rice bran, using a commercial protease (Alcalase), was investigated and evaluated by response surface methodology. The effect of enzyme concentration was most significant on oil and protein extraction yields, whereas incubation time and temperature had no significant effect. The maximal extraction yields of oil and protein were 79 and 68%, respectively. Further, the quality of oil recovered from the process in terms of free fatty acid, iodine value, and saponification value was comparable with solvent‐extracted oil and commercial rice bran oil, but the peroxide value was higher.
Adsorption of chromium(VI) and nickel(II) ions on acid‐ and heat‐activated deoiled spent bleaching clay
Authors: Seng C. E. , Lee C. G. , Liew K. Y. 
Published: November 2006

AbstractDe‐oiled spent bleaching clay was activated either by acid treatment followed by heat activation or by heat activation alone at temperatures between 200 and 800°C. The surface area of the heat‐activated clay attained a maximal value of ≈120 m2 g−1 at temperatures between 400 and 500°C while the acid‐heat‐treated clay attained maximal surface area of ≈140 m2 g−1. The adsorption capacities of chromium [Cr(VI)] for both series studied increased as the activation temperature increased until 300°C and decreased again at higher temperatures. At lower pH, more than 95% of the Cr(VI) was absorbed in a solution with initial concentration of 1 mg L−1 per gram of adsorbent activated at 300°C. The adsorption patterns followed Freudlich's isotherms. Two maximal values of adsorption capacities of nickel [Ni(II)] were observed at activation temperatures of 200 and 500°C for acid‐treated samples, whereas these were at 200 and 700°C for the nonacid‐treated samples. The amount of Ni(II) adsorbed increased with the pH of the solution for all samples studied. The maximal adsorption capacities of the adsorbents in solution containing initial Ni(II) concentration of 5 mg L−1 per 0.5 g of adsorbent and at pH 6 were found to be 44 and 42%, respectively, for the acid‐treated sample activated at 500°C and for the nonacid‐treated sample activated at 700°C. They all obeyed both the Langmuir's and Freundlich's isotherms.
Analytical characteristics of virgin olive oil from young trees (arbequina cultivar) growing under linear irrigation strategies
Authors: Tovar M. Jesús , Motilva M. José , Luna M. , Girona J. , Romero M. Paz 
Published: November 2006

AbstractThe effect of a linear (vs. effective crop coefficient, Kc), irrigation strategy applied to young olive trees (Arbequina cv.) on the qualitative and quantitative parameters of virgin olive oil quality was studied. Although linear irrigation strategy did not affect the quality indexes used to classify olive oil by commercial grades, it did influence other important parameters such as total phenol content, bitter index oxidative stability, and the sensorial appraisal. All of these of olive oil qualities were negatively associated with the amount of applied irrigation water. Pigment content of oils determined by carotenoid and chlorophylls also was negatively associated with the amount of water supplied. No consistent relation was found for α‐tocopherol and fatty acid content of olive oil in relation to these treatments.
Protein and lipid films at equilibrium at air‐water interface
Authors: Niño M. Rosario Rodríguez , Sánchez Cecilio Carrera , Fernández Marta Cejudo , Patino Juan M. Rodríguez 
Published: November 2006

AbstractThe surface activity of β‐casein, caseinate, and a whey protein isolate in aqueous solutions has been investigated over a range of protein concentrations (1·10−5to 5% w/w) at pH 5 and 7. The surface pressure data were determined by the Wilhelmy plate method. Surface pressure data at low protein concentration indicate a low surface activity that rises to a plateau as the monolayer is saturated at higher protein concentrations. The protein concentration and the surface pressure at the plateau depend on the pH and the type of protein in the aqueous phase. Protein‐monoglyceride interactions were investigated by spreading an insoluble monoglyceride (monopalmitin, monoolein, or monolaurin) on a film of protein previously adsorbed on the interface at equilibrium. The existence of protein‐monoglyceride interactions depends on the interfacial composition and on the protein/monoglyceride ratio. The surface activity of mixed protein‐monopalmitin and protein‐monoolein films is determined by the lipid as the surface pressure of the mixed film is the same as the monoglyceride equilibrium spreading pressure, and the monolayer is not saturated by the protein. However, the protein determines the surface activity of mixed protein‐monopalmitin and protein‐monoolein films as the protein saturates the monolayer. For protein and monolaurin mixed films, protein determines the surface activity over the range of protein‐monolaurin compositions due to monolaurin dissolution in the bulk aqueous phase.
Relationship of electronic nose analyses and sensory evaluation of vegetable oils during storage
Authors: Shen N. , Moizuddin S. , Wilson L. , Duvick S. , White P. , Pollak L. 
Published: November 2006

AbstractOff‐flavors associated with oxidized oils make it difficult to recruit sensory panelists to evaluate the oils. Using an instrument called the “electronic nose” to monitor the formation of volatile compounds associated with off‐flavors could help to interpret oil oxidation studies in part to supplement human sensory panels. No published studies evaluate the correlation of oil oxidation sensory data and “electronic nose” analyses. Therefore, this project was designed to determine the correlation between sensory evaluation and “electronic nose” analyses. Canola, corn, and soybean oils were stored at 60°C in the dark until sufficiently oxidized. On days 0, 3, 6, 9, and 12, oils were evaluated for peroxide value, for volatile compounds by “electronic nose,” and for off‐flavor by sensory evaluation. The results suggest that the “electronic nose” is capable of measuring changes in volatile compounds associated with oil oxidation and could be used to supplement data obtained from sensory evaluations.
Oxidation of phytosterols in a test food system
Authors: Oehrl Lisa L. , Hansen Arthur P. , Rohrer Cynthia A. , Fenner Gregory P. , Boyd Leon C. 
Published: November 2006

AbstractThe oxidative stability of phytosterols in canola, coconut, peanut, and soybean oils was examined under simulated frying conditions of 100, 150, and 180°C for 20 h. The degree of oxidative decomposition was assessed by the loss of phytosterols, accumulation of phytosterol oxides, and the change in fatty acid profiles. The phytosterol oxides produced in the oils were identified using mass spectroscopy. Oils with higher levels of polyunsaturated fatty acids showed greater amounts of sterol loss; however, the sterol loss was less complete than in the more saturated oils. A greater variety of sterol oxides was observed at the lower temperatures of 100 and 150°C compared to 180°C. This study demonstrates that under conditions similar to frying, there is a loss of phytosterols and polyunsaturated fatty acids. The accumulation of phytosterol oxides may be temperature‐limited because of further break‐down into products not measurable by typical gas chromatography‐mass spectrometry techniques.
Effect of nitrogen and zinc fertilization and plant growth retardants on cottonseed, protein, oil yields, and oil properties
Authors: Sawan Zakaria M. , Hafez Saeb A. , Basyony Ahmed E. 
Published: November 2006

AbstractThe increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture. It is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Field experiments were conducted in two successive seasons at the Agricultural Research Center (Giza, Egypt) on cotton (Gossypium barbadense L. cv. Giza 75) to determine the effect of nitrogen (N) fertilizer rate (107 and 161 kg of N/ha applied as ammonium nitrate containing 33.5% N in two equal doses at 6 and 8 wk after sowing), together with foliar applications of plant growth retardants (mepiquat chloride “Pix”, chloromequat chloride “Cycocel”, and daminozide “Alar”, each applied once at 288 g active ingredient/ha, after 75 d from sowing) and zinc (Zn) (applied in chelated form after 80 and 95 d from sowing at 48 g of Zn/ha) on seed, protein and oil yields and oil properties of cotton. The higher N‐rate, as well as the application of all growth retardants and Zn, resulted in an increase in cottonseed yield, seed protein content, oil and protein yields/ha, seed oil refractive index, unsaponifiable matter, and total unsaturated fatty acids (oleic and linoleic). These treatments tended to decrease oil acid value, saponification value, and total saturated fatty acids. The seed oil content tended to decrease as N‐rate increased and increased with the application of all growth retardants and Zn. There were some differences between Pix, Cycocel, and Alar regarding their effects on the studied characters. The highest increase in seed, oil, and protein yields/ha was found with Pix, followed by Cycocel. The Cycocel treatment gave the lowest total saturated fatty acids oil content, followed by Alar.
Esterification of glycerol with conjugated linoleic acid and long‐chain fatty acids from fish oil
Authors: Torres Carlos F. , Garcia Hugo S. , Ries Jason J. , Hill Charles G. 
Published: November 2006

AbstractFree fatty acids from fish oil were prepared by saponification of menhaden oil. The resulting mixture of fatty acids contained ca. 15% eicosapentaenoic acid (EPA) and 10% docosahexaenoic acid (DHA), together with other saturated and monounsaturated fatty acids. Four commercial lipases (PS from Pseudomonas cepacia, G from Penicillium camemberti, L2 from Candida antarctica fraction B, and L9 from Mucor miehei) were tested for their ability to catalyze the esterification of glycerol with a mixture of free fatty acids derived from saponified menhaden oil, to which 20% (w/w) conjugated linoleic acid had been added. The mixtures were incubated at 40°C for 48h. The ultimate extent of the esterification reaction (60%) was similar for three of the four lipases studied. Lipase PS produced triacylglycerols at the fastest rate. Lipase G differed from the other three lipases in terms of effecting a much slower reaction rate. In addition, the rate of incorporation of omega‐3 fatty acids when mediated by lipase G was slower than the rates of incorporation of other fatty acids present in the reaction mixture. With respect to fatty acid specificities, lipases PS and L9 showed appreciable discrimination against esterification of EPA and DHA, respectively, while lipase L2 exhibited similar activity for all fatty acids present in the reaction mixture. The positional distribution of the various fatty acids between the sn‐1,3 and sn‐2 positions on the glycerol backbone was also determined.
Virgin olive oil: Free radical production studied with spin‐trapping electron paramagnetic resonance spectroscopy
Authors: Skoutas D. , Haralabopoulos D. , Avramiotis S. , Sotiroudis T. G. , Xenakis A. 
Published: November 2006

AbstractSpin trapping using 5,5‐dimethyl‐1‐pyrroline N‐oxide (DMPO) has been used to detect and distinguish free radicals in samples of Greek extra virgin olive oils. A number of the samples examined immediately after the addition of the spin trap showed a spontaneous complex electron paramagnetic resonance (EPR) signal. The majority of DMPO‐radical adducts formed (80–90%) represented peroxyl and alkoxyl radical adducts. Similar spectra were recorded when DMPO was added in oxidized triolein and then treated with Fe2+, Fe3+, or Cu2+ or when EPR‐silent olive oil samples were treated with these metallic ions. Metal ion‐catalyzed decomposition of triolein hydroperoxides, as recorded by EPR signal intensity, increased with increasing metal ion concentration in the micromolar range. The relative concentration of alkoxyl‐DMPO adducts increased with increasing Fe2+ or Fe3+ concentration, whereas that of peroxyl‐DMPO species decreased. In contrast, the relative concentrations of alkoxyl and peroxyl species produced by Cu2+ were similar over the whole metal concentration range examined. Exposure of EPR‐silent virgin olive oil or oxidized triolein to ultraviolet light in the presence of DMPO resulted in the detection of a three‐line spectrum characterized by wide line widths.