bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic conversion of steryl esters to free sterols
Authors: Shimada Yuji , Nagao Toshihiro , Watanabe Youichi , Takagi Yoshiaki , Sugihara Akio 
Published: November 2006

AbstractConversion of oleic acid phytosteryl esters (OASE) to free phytosterols (referred to as sterols) by an enzymatic process was attempted. Enzymatic hydrolysis of OASE reached a steady state at 55–60% hydrolysis, but addition of methanol (MeOH) significantly accelerated the conversion of OASE to sterols. Screening of commercially available enzymes indicated that Pseudomonas aeruginosa lipase was most effective for the conversion. Based on the study of several factors affecting the reaction, the optimal conditions were determined as follows: ratio of OASE to MeOH, 1∶2 (mol/mol); water content, 10 wt%; lipase amount, 20 U/g by weight of reaction mixture; temperature, 30°C. When the reaction was conducted for 48 h with stirring, the conversion reached 98%. FAME accumulated in the reaction mixture, but FFA did not, indicating that the FAME was poorly recognized as a substrate in the reverse conversion of sterols to OASE but the FFA was easily recognized as a substrate. The high conversion of OASE to sterols was therefore due to elimination of FFA from the reaction system. After the enzymatic reaction, the oil layer was fractionated at −20°C with 5 vol parts of n‐hexane. Sterols were efficiently purified in the resulting precipitate (92% recovery, 99% purity).
Chromatic evolution of virgin olive oils submitted to an accelerated oxidation test
Authors: Ceballos Claudio , Moyano María José , Vicario Isabel M. , Alba José , Heredia Francisco J. 
Published: November 2006

AbstractSix samples of virgin olive oil obtained from several varieties of olive fruits (Picual, Manzanilla, Lechín, and Arbequina) were submitted to an accelerated oxidation process during a 63‐h period under the conditions of the oil stability index (OSI), as measured by a Rancimat (100°C) apparatus. Spectra were measured every 3 h, and chlorophyll and carotenoid indexes and CIFLAB color ordinates were calculated. As oxidation time increased, remarkable changes in the spectral characteristics and color ordinates were observed. Oxidation provoked less vivid colors (lower values for chroma, C*ab) in all the samples; however, only some varieties became darker (lower values for lightness, L*). The pigment loss calculated for oxidized oils was 67% for the carotenoid index and 58% for the chlorophyll index. Mathematical models are offered to predict color changes with time of storage at 20°C.
Continuous abrasive method for mechanically fractionating flaxseed
Authors: Wiesenborn Dennis , Tostenson Kristi , Kangas Nancy 
Published: November 2006

AbstractBoth the flaxseed hull, which is rich in the lignan secoisolariciresinol diglucoside (SDG), and the embryo, which is rich in oil with high α‐linolenic acid content, are of interest for functional food use. A mechanical process for preparing hull‐and embryo‐rich fractions was developed and characterized. The process consisted of three pearlers, a sifter that yielded fines, and a gravity table that yielded final hull and embryo fractions. The SDG contents of fractions correlated inversely with oil content, showing that oil content indicated purity of both embryo and hull fractions and that the fines were essentially hull particles. Process performance depended on seed variety, moisture content, and feed rate; the best yields were 285 g hull +fines/kg for low‐moisture Omega flaxseed, and 470 g embryo/kg seed for low‐moisture Neche. Corresponding oil contents of those fractions were 28.8 and 47.4%, respectively. This process appears to be commercially feasible, provided it can be scaled up. A single stage was used to identify features that should be incorporated into a scaled‐up unit, for example a 7‐mesh screen in the pearler chamber rather than 6‐ or 8‐mesh, and use of an overhead feed inlet to the chamber to direct seed into the disk‐plate gap.
Processing of tocopherol and FA systems using a nonporous denser polymeric membrane
Authors: Nagesha G. K. , Subramanian R. , Sankar K. Udaya 
Published: November 2006

AbstractTocopherols permeated preferentially over oleic acid in model systems and over oleic acid and other oil constituents during processing of soy deodorizer distillate (DOD) when using nonporous denser polymeric membranes (i.e., denser than reverse osmosis membranes). This observation was unexpected, since the separation in a denser membrane is generally based on a solution‐diffusion mechanism. That tocopherols are less polar than oleic acid appears to have facilitated the preferential permeation of tocopherols through the hydrophobic membrane. Selectivity of the membrane for tocopherols improved with esterified soy DOD. The presence of FAME decreased the viscosity of the feed and thereby increased convective flow, which in turn improved permeate flux. FAME appeared to have exerted positive coupling effects with tocopherols, having better selectivity in spite of the greater solubility of FAME in the membrane material. Membrane selectivity for tocopherols improved upon dilution of the feed material with hexane, perhaps owing to greater solubility of tocopherols in hexane (nonpolar) than other feed constituents.
A density functional theory study of structure‐activity relationships in caffeic and dihydrocaffeic acids and related monophenols
Authors: Bakalbassis Evangelos G. , Nenadis Nikolaos , Tsimidou Maria 
Published: November 2006

AbstractStructure‐activity relationships in the antioxidants caffeic acid and dihydrocaffeic acid as well as in the monophenols isoeugenol, eugenol, and dihydroeugenol were investigated by using the density functional theory (DFT). The higher antioxidant activity of caffeic acid, among the rest, could be attributed to its lower difference in the heat of formation (ΔHOF) value. Dihydrocaffeic acid exhibits less antioxidant activity than caffeic acid, owing to both its higher ΔHOF value and its limited spin delocalization. These two latter findings could also account for the lower antioxidant activity of both eugenol and dihydroeugenol as compared to isoeugenol. DFT calculations afford a good molecular descriptor, ΔHOF, that correlates well with the antioxidant activity in molecules exhibiting similar structural characteristics. The presence of a simple double bond in the side chain makes a difference in the antioxidant activity only if it leads to an extended conjugation. Calculated dipole moment values for both the parent molecules and the respective phenoxyl radicals correlate well with their antioxidant efficiency in some instances.
Antioxidant effects of protein hydrolysates in the reaction with glucose
Authors: Guérard Fabienne , Sumaya‐Martinez Maria‐Teresa 
Published: November 2006

AbstractMaillard reaction products (MRP) obtained by reaction between glucose and protein hydrolysates from casein and fish were investigated. The influence of parameters such as reaction time and glucose concentration was studied. The antioxidative activity of MRP was determined by using the β‐carotene/linoleate model and the 1,1‐diphenyl‐2‐pricrylhydrazyl method. All experiments showed that the antioxidative effect was improved by 20–30% when the hydrolysates were reached with glucose. A dramatic increase in antiradical efficiency of the MRP (up to 75%) was also observed. The study of the chromatographic profiles obtained before and after the Maillard reaction found changes in absorbance at 280 nm, indicating molecular rearrangements that could be involved in the improvement of the antioxidative and free radical‐scavenging activities.
Measurement of foaming of frying oil and effect of the composition of TG on foaming
Authors: Negishi Satoshi , Itakura Megumi , Arimoto Shin , Nagasawa Takeshi , Tsuchiya Kinya 
Published: November 2006

AbstractWe describe a method developed to quantify the amount of foam in frying oils. In this method the foam was quantified by digitizing photographic images that were taken continuously at 1‐s intervals; spots showing more than a certain luminance were considered as foam. The ratio of total foaming area to the whole oil surface was integrated to obtain the intergration of foam (IF) index as a parameter of the extent of foaming. There was a good correlation between this method and the visual evaluation done by a group of panelists. Furthermore, the foaming tendency correlated with the distribution of TG by M.W. when the IF was plotted against the foam index of TG (FIT), which reflects the M.W. distribution. A correlation was found between the FIT value of oil and foaming on frying, indicating that when the FIT value is small, the oil foams less. Based on the results of this investigation, we have designed a method to obtain edible oils consisting of medium‐chain FA that not only are nutritious but also have good cooking properties.
Trans FA content in Danish margarines and shortenings
Authors: Leth Torben , Bysted Anette , Hansen Kirsten , Ovesen Lars 
Published: November 2006

AbstractMargarines and shortenings have been major contributors to the intake by humans of the probably atherogenic trans FA (TFA). In 1999, all 73 brands of margarines and shortenings on the Danish market were analyzed by GLC on a 50‐m highly polar capillary column, and the results were compared with similar investigations in 1992 and 1995. A gradual decline of TFA in Danish margarines was observed. From 1992 to 1995, a reduction of TFA from 10.4 to 3.6% took place in margarines with 20–40% linoleic acid. In 1999, TFA was practically absent in all the margarines, but it remained unchanged in shortenings, averaging about 6–7%. Long‐chain TFA from hydrogenated fish oil, although present in 13 brands in 1995, were not found at all in the 1999 samples. Trans‐linoleic acids or CLA were not found. The reduction in TFA content in margarines has not resulted in a systematic change over the years in the content of saturated FA, monounsaturated FA, or PUFA. Calculated from sales figures, the intake of TFA decreased from 2.2 g per capita per year in 1992, to 1.5 g in 1995, and to 0.4 g in 1999.
Crystallization of sunflower oil waxes
Authors: Martini S. , Añón M. C. 
Published: November 2006

AbstractActivation free energies of nucleation (ΔGc) were calculated using induction times of crystallization measurements. Results showed that ΔGc decreased exponentially as wax concentration increased at a constant crystallization temperature (Tc). In contrast, for a constant supersaturation, ΔGc increased from 12 to 22°C but decreased between 22 and 35°C. Melting behavior of purified waxes and solutions of purified waxes in sunflower oil were studied by DSC after crystallization at fast and slow cooling rates (20 and 1°C/min, respectively). Low supercooling temperatures (Tc>65°C) showed an increase in the onset temperature (T0) as Tc increased for both fast and slow cooling rates. Broader peaks were obtained for samples crystallized at a slow cooling rate at the same Tc. Regarding the solutions of waxes in sunflower oil, the wax concentration (supersaturation of the system) controlled crystallization as well as Tc. As Tc increased, the enthalpy (ΔH) decreased at a constant wax concentration. When wax concentration decreased, ΔH decreased at a constant Tc. For a low driving force, a small shoulder was obtained in the DSC diagrams owing to some type of fractionation. These results showed that wax crystallization is affected by different experimental parameters, such as Tc and cooling rate, depending on the wax concentration of the sample.
Variability in soy flour composition
Authors: Porter Michael A. , Jones Alison M. 
Published: November 2006

AbstractSoy flour is commonly used as a protein source in industrial fermentations. As an essentially natural product, the composition of soy flour can vary from year to year as a result of changes in growing conditions. The composition of soy flour from a single manufacturing plant was determined over an 8‐yr period. Protein concentration varied from 51.2% in the 1997 crop to 53.2% in the 1998 crop, but overal amino acid composition was relatively constant. The concentrations of valine, isoleucine, tyrosine, and alanine showed significant variation between years. Crude fat levels were steady, but the fat by acid hydrolysis (FAH) levels varied, suggesting changes in the level of phospholipids. The difference between the crude fat and FAH analyses (a proxy for phospholipids) had a strong positive correlation (P<0.001) with the total phosphorus concentration, consistent with this interpretation. FA distribution varied year to year with linoleic acid providing the most dramatic effect. Fe and P concentrations showed significant variation, but Al, Ca, Cu, K, Mg, Mn, Mo, Ni, and Zn did not vary significantly. Although P concentration had a significant correlation with proxy phospholipid levels, there was not a significant correlation between P concentration and phytic acid concentrations
Lipid hydrolysis and oxidation on the surface of milled rice
Authors: Lam Henry S. , Proctor Andrew 
Published: November 2006

AbstractThe changes in milled rice FFA content and composition and in conjugated diene (CD) content and bacterial, yeast, and mold counts were determined at 24, 37, and 50°C and 70% RH over 50 d. There was a rapid rate of FFA formation during the first few days of storage, which was optimal at 37°C, but that slowed after 2, 4, and 5 d at 37, 24, and 50°C, respectively. There was a second increase in FFA after about day 12 that increased with increasing temperature, indicating nonlipase hydrolysis. Linoleic and oleic acids were the main components of the total FFA produced on the surface of milled rice. The pattern of CD development followed that of FFA increase. Bacterial growth correlated with increased FFA levels after 12 d of storage, suggesting that bacterial lipase rather than bran lipase may be responsible for rice lipid hydrolysis
Oxidative stability of walnut oils extracted with supercritical carbon dioxide
Authors: Crowe Tammy D. , White Pamela J. 
Published: November 2006

AbstractSupercritical carbon dioxide (SC‐CO2) was used to partially defat walnuts, and the oxidative stability of the extracted walnut oils was assessed. The SC‐CO2‐extracted oils were less stable during accelerated storage in the dark than was pressed walnut oil, as determined by PV, headspace analysis by solid‐phase microextraction, and sensory methods. The SC‐CO2‐extracted oils, however, exhibited greater photo‐oxidative stability than did pressed walnut oil by all of these methods, possibly because of the presence of chlorophyll in the pressed oil. Oxidative stability indices and tocopherol contents were significantly lower in the SC‐CO2‐extracted oils than in pressed oil.
Tocol levels in milling fractions of some cereal grains and soybean
Authors: Ko Soon‐Nam , Kim Chul‐Jin , Kim Hakryul , Kim Chong‐Tai , Chung Soo‐Hyun , Tae Beom‐Seok , Kim In‐Hwan 
Published: November 2006

AbstractTocol levels in the milling fractions of rice, barley, corn, wheat, and soybeans were analyzed by HPLC with a fluorescence detector. Among all milling fractions tested in this study, rice germ had the highest total tocol levels. In the four milling fractions of barley, except pearling flour, all eight tocol isomers were detected, and they were more uniformly distributed than in any other cereal grains measured in this study. The total tocol and α‐tocopherol levels of wheat germ were significantly (P<0.05) higher than the other wheat milling fractions. A significantly (P<0.05) higher proportion of γ‐tocopherol was obtained from corn germ (71.5%) and endosperm (50.3%) than from corn hulls. Only four tocol isomers (α‐, β‐, γ‐, and δ‐tocopherol) were detected in soybean milling fractions; no tocotrienol isomers were detected. The δ‐tocopherol level of soybean endosperm, although minor, was significantly higher than those in milling fractions of other cereal grains in this study.
Determination of hexane residues in vegetable oils with FTIR spectroscopy
Authors: Mirghani M. E. S. , Che Man Y. B. 
Published: November 2006

AbstractThe FTIR spectroscopy method was developed for the determination of hexane residues in palm and groundnut (peanut) oils. The method was based on horizontal attenuated total reflectance with a ZnSe crystal at 45° at room temperature, and partial least squares (PLS) statistics were used to derive calibration models. The accuracy of the method was comparable to that of the AOCS Method Ca 3b‐87, with coefficients of determination (R2) of 0.9866 and 0.9810 for palm and groundnut oils, respectively, and SE of calibration of 3.83 and 4.91, respectively. The calibration models were validated, and the R2 of validation and the SE of prediction computed. The SD of the difference for repeatability for the method was comparable to that for the standard AOCS method when used for palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy has an advantage over present chemical methods, which require preparation of the oil using toxic solvents before GC.
Inhibitive effect of FA derivatives on mild steel corrosion in the presence of formic acid
Authors: Quraishi M. A. , Ansari Farhat A. 
Published: November 2006

AbstractThe influence of selected long‐chain FA hydrazides and thiosemicarbazides on the corrosion inhibition of mild steel in the presence of 20% formic acid was studied. The inhibition efficiency of these compounds varied with concentration, temperature, and immersion time. All the FA derivatives in the formic acid solution followed Temkin's adsorption isotherm. The activation energies and free energies of adsorption of all the hydrazides and thiosemicarbazides also were calculated. Potentiodynamic polarization studies indicated that all the tested compounds were of mixed type. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition.
Preparation of fatty 3,5‐disubstituted isoxazole compounds from FA esters
Authors: Kenar James A. , Wetzel Amanda R. 
Published: November 2006

AbstractLong‐chain fatty compounds containing an isoxazole heterocyclic ring system substituted at the 3‐ and 5‐ring positions were prepared in moderate to good yields (40–64%) in one pot by condensing FA esters such as methyl palmitate, stearate, oleate, or linoleate with the lithiated anion of N‐(isopropylidene)isopropylamine followed by dehydrative cyclization. This approach allows readily available FA esters to be utilized and incorporated into the construction of the isoxazole ring system. These novel products were isolated then characterized by NMR, IR spectroscopy, GC‐MS, and m.p. Mass spectra of the fatty isoxazole compounds, derived utilizing EI ionization, showed distinctive cleavage patterns that occurred uniformly along the fatty alkyl chain allowing the position of double bonds to be readily located. Two prominent ions at m/z 97 and 110 were common to all the fatty isoxazole compounds examined and were presumably from a McLafferty rearrangement and a cyclization displacement reaction, respectively.
An efficient method for the purification of arachidonic acid from fungal single‐cell oil (ARASCO)
Authors: Vali Shaik Ramjan , Sheng Huei Ya , Ju Yi‐Hsu 
Published: November 2006

AbstractPUFA, such as arachidonic acid (AA), have several pharmaceutical applications. An efficient method was developed to obtain high‐purity arachidonic acid (AA) from ARASCO, a single‐cell oil from Martek (Columbia, MD). The method comprises three steps. In the first step, AA was enriched from saponified ARASCO oil by low‐temperature solvent crystallization using a polar, aprotic solvent, which gave a FA fraction containing 75.7% AA with 97.3% yield. The second step involved enriching AA content via lipase‐catalyzed selective esterification of FA with lauryl alcohol. When a mixture of 1 g FA/lauryl alcohol (2∶1 mol/mol), 50 mg Candida rugosa lipase, and 0.33 g water was incubated at 50°C for 24 h with stirring at 400 rpm, the AA content in the unesterified FA fraction was as much as 89.3%, with ca. 90% yield. Finally, a solvent extraction procedure, in which acetonitrile was the extracting solvent, was used to enrich AA from FA fraction dissolved in n‐hexane. The best results were obtained when 2 g FA was dissolved in 80 mL hexane and extracted twice, each time with 20 mL acetonitrile at −20°C, by allowing 2 h storage. This step gave a FA fraction containing 95.3% AA with 81.2% yield. By using this three‐step process the AA content in the saponified single‐cell oil (ARASCO) was increased from 38.8 to 95.3% with a total yield of ca. 71%.
Oxidative instability of CLA concentrate and its avoidance with antioxidants
Authors: Lee Junsoo , Lee Seon‐Mi , Kim In‐Hwan , Jeong Jae‐Hong , Rhee Chul , Lee Kwang‐Won 
Published: November 2006

AbstractThis study evaluated the effectiveness of antioxidants, such as BHA, BHT, TBHQ, propyl gallate (PG), α‐tocopherol (α‐1), green tea extract (GTE), and rosemary extract (RE) on oxidative stability of CLA concentrate. Stability of CLA concentrate stored in air at 45°C up to 44 d was assessed by PV. During the storage period, the PV of the control CLA concentrate sample increased from 0.20 (fresh oil) to 1654 meq/kg (oxidized oil). On the other hand, the PV for CLA concentrates treated with 200 ppm of the single synthetic antioxidants, BHA, BHT, TBHQ, and PG, increased from 0.20 to 81, 107, 78, and 101 meq/kg, respectively. Also, the PV of CLA concentrate with the addition of 200 ppm single natural antioxidants α‐T, GTE, and RE lowered the final PV to 122, 140, and 110 meq/kg, respectively. Under our experimental conditions, the protective effect of 200 ppm antioxidant was in the order of TBHQ>BHA>PG>BHT>RE>α‐T> GTE. These results suggest that the appropriate use of antioxidants prolongs the oxidative stability of CLA concentrate.
Preparation and properties of lubricant basestocks from epoxidized soybean oil and 2‐ethylhexanol
Authors: Hwang Hong‐Sik , Adhvaryu Atanu , Erhan Sevim Z. 
Published: November 2006

AbstractSynthetic lubricant basestocks were prepared from epoxidized soybean oil (ESO) and 2‐ethylhexanol (2‐EH) to be used alone or with polyalphaolefin (PAO). Sulfuric acid‐catalyzed reaction of ESO with 2‐EH involves a ring‐opening reaction at the epoxy group followed by transesterification at the ester group. Reaction with other catalysts including p‐toluenesulfonic acid, Dowex 50W‐8X, boron trifluoride, and sodium methoxide was also examined. Pour points of the products were observed as lows as −21 and −30°C without and with 1% of pour point depressant, respectively. When the hydroxy groups in the products were esterified with an acid anhydride, lower pour points were observed. Pour point depression of the product by adding PAO has been tested. Oxidative stability of the product was examined using pressurized DSC and compared with those of synthetic lubricant basestocks, PAO, and a synthetic ester.
Hydrolysis of mono‐ and diepoxyoctadecanoates by alumina
Authors: Piazza George J. , Nuñez Alberto , Foglia Thomas A. 
Published: November 2006

AbstractIn this study it is shown that the epoxide derivative of oleic acid, methyl 9,10‐epoxyoctadecanoate, is readily hydrolyzed to a diol when exposed to a commercial preparation of neutral alumina. Comparison of 1H and 13C NMR spectra of the diol with those of standards showed that the product was the threo isomer. When methyl 9, 10–12,13‐diepoxyocta‐decanoate was treated with alumina, a mixture of dihydroxy‐tetrahydrofuran regioisomers, methyl 9,12‐epoxy‐10,13‐dihydroxystearate and methyl 10,13‐epoxy‐9,12‐dihydroxystearate, was obtained. These results show that alumina is an unsuitable support for epoxidation catalysts. However, alumina‐catalyzed hydrolysis of fatty epoxides is an efficient way to synthesize polyhydroxy materials, and these materials are suitable for several industrial applications.