bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of specific‐structured lipids by enzymatic interesterification in a pilot continuous enzyme bed reactor
Authors: Xu X. , Balchen S. , Høy C. E. , Adler‐Nissen J. 
Published: May 2007

AbstractProduction of specific‐structured lipids (interesterified lipids with a specific structure) by enzymatic interesterification was carried out in a continuous enzyme bed pilot scale reactor. Commercial immobilized lipase (Lipozyme IM) was used and investigations of acyl migration, pressure drop, water dependence, production efficiency, and other basic features of the process were performed. The extent of acyl migration (defined as a side reaction) occurring in the present enzyme bed reactor was compared to that in a pilot batch reactor. The continuous enzyme bed reactor was better than the batch reactor in minimizing acyl migration. Generally the former produced about one‐fourth the acyl migration produced by the latter at a similar extent of incorporation. Pressure drop and production efficiency were evaluated in order to obtain a suitable yield in one reaction step. High incorporation was favored by high substrate ratios between acyl donors and oils, requiring long reaction times on the enzyme bed. Under these conditions, the pressure drop of the reactor was modeled statistically and theoretically. Residence time, water content, and effects of mass transfers were also investigated. Incorporation of medium‐chain fatty acids increased with increased residence time. Approximately 40% of lipase activity was lost after a 4‐wk run. External mass transfer was not a major problem in the linear flow range, but internal mass transfer did impose some transfer limitations.
Effects of storage conditions on lipid oxidation in infant formulas based on several protein sources
Authors: Angulo A. J. , Romera J. M. , Ramírez M. , Gil A. 
Published: May 2007

AbstractThe time course of several lipid oxidation parameters in infant formulas was the main focus of this study. Infant formulas based on different protein sources (milk protein, isolated soy protein, and hydrolyzed milk protein) were stored at different temperatures (32 and 55°C) in sealed containers in air for 1 yr. Levels of thiobarbituric acid‐reactive substances and 7‐ketocholesterol, and losses of essential fatty acids and tocopherols were measured to monitor lipid oxidation. Tocopherol losses and 7‐ketocholesterol concentrations were better lipid oxidation parameters than the others. Their concentration and losses depended on type of infant formula, storage temperature, and time.
Rapid synthesis of fatty acid esters for use as potential food flavors
Authors: Kim Jungbae , Altreuter David H. , Clark Douglas S. , Dordick Jonathan S. 
Published: May 2007

AbstractLipase‐catalyzed esterification has been performed in hexane to generate novel mixtures of fatty acid esters from specially chosen combinations of fatty acids and alcohols. By varying the alcohol and enzyme compositions in the enzymatic reactions, different ester mixtures were produced, which were further purified and analyzed for ester composition by gas chromatography‐mass spectrometry. Depending on the combination of alcohols and enzymes used, the final ester mixture exhibited significant compositional variation. These mixtures could be manipulated at the synthesis step, thereby enabling a high degree of product control. Such manipulation over enzyme‐catalyzed ester synthesis in mixtures may be useful in the preparation of ester flavors for use in the food industry.
Hydrogen‐donating mechanism of rosmariquinone, an antioxidant found in rosemary
Authors: Hall Clifford A. , Cuppett Susan L. , Dussault Pat 
Published: May 2007

AbstractRosmariquinone (RQ), an ortho‐quinone diterpenoid found in rosemary, was shown to act as a hydrogen‐donating antioxidant. The proposed mechanism is based on the isolation of the catechol intermediate arucadiol (AD) in methyl oleate test systems. AD was also observed in a bulk soybean oil oxidation experiment, which supports the observation that RQ is converted to AD during oxidation of the oil. Because AD was found in both light‐induced oxidation and autoxidation test systems, the antioxidant mechanism proceeds in a similar manner. The antioxidant activities of RQ and AD were not significantly different in the autoxidation experiments, while AD was a significantly better (P<0.05) antioxidant than RQ in the light‐induced oxidation.
Solvent‐free glycerolysis catalyzed by acetone powder of Nigella sativa seed lipase
Authors: EI Naciye , Dandik Levent , Aksoy H. Ayşe 
Published: May 2007

AbstractThe solvent‐free glycerolysis of used sunflower oil catalyzed by acetone powder of Nigella sativa seeds was investigated. The highest partial acylglycerols yield was obtained at 60°C. The glycerolysis reactions, conducted at molar ratios of 1:1, 2:1, and 3:1 of oil to glycerol keeping the acetone powder content at 30% based on oil weight and the temperature at 60°C, approached equilibrium after 2 h. The highest partial acylglycerol content of the products was 66% (1:1 molar ratio) and 60% (2:1 molar ratio).
Antioxidant properties of desferrioxamine E, a new hydroxamate antioxidant
Authors: Shimoni E. , Ampel M. , Zähner H. , Neeman I. 
Published: May 2007

AbstractAntioxidant properties of desferrioxamine E, a cyclic trihydroxamate produced by microorganisms, were tested and compared to those of desferrioxamine B and butylated hydroxyanisole (BHA). Desferrioxamine E exhibited significant antioxidant effects in linoleic acid emulsions as well as in emulsions of linoleic acid and β‐carotene. In concentrations of 100 ppm, the effect of both desferrioxamines in linoleic acid emulsion was equal to that of BHA. The antioxidant activity of the desferrioxamines in emulsions of β‐carotene and linoleic acid was significantly higher than that of BHA. In addition, the initial rate of β‐carotene destruction was significantly lower when desferrioxamines were added to the emulsion.
Triterpene alcohols and fatty acids in lipids and nonsaponifiable matter of Lapsana communis L. subspecies communis (Asteraceae)
Authors: Fontanel Didier , Kargol Michael , Gueiffier Alain , Viel Claude 
Published: May 2007

AbstractThe oil content of samples of aerial parts of Lampsana communis L. subsp. communis, harvested in Indre et Loire (France) at different periods, varies from 1.1 to 2.1%. Nonsaponifiable matter in these samples represents 36.0 to 65.7% of the oil. Yields of triterpene alcohols of nonsaponifiable matter (25.9 to 81.8%) were determined by preparative thin‐layer chromatography after saponification. Seven of them were identified by gas chromatography‐mass spectrometry (GC‐MS). Six of the fatty acids in the aerial parts have also been identified by GC‐MS. The seeds of L. communis contain 2.6% oil.
Trans‐18:1 acid content and profile in human milk lipids. Critical survey of data in connection with analytical methods
Authors: Wolff Robert L. , Precht Dietz , Molkentin Joachim 
Published: May 2007

AbstractThis study presents an in‐depth, critical survey of the current knowledge about trans‐ 18:1 acid content and profile in human milk lipids. Emphasis is placed on the analytical methods employed to quantitate trans‐ 18:1 acids, most of which lead to imprecise quantitative data. It is demonstrated that data obtained by single gas‐liquid chromatography (GLC) on polar capillary columns are underestimates by 25–40%. Several experiments indicate that the total content of trans‐18:1 acids in human milk is directly related to the quantities ingested the previous day(s), provided no gross weight loss occurs during breast‐milk feeding. Equations have been proposed to describe this relationship, and apparently the percentage of trans‐18:1 isomers, relative to total fatty acids, is approximately three‐fourths the quantity (in g) ingested by lactating mothers. That is, the determination of the trans‐18:1 acid percentage in human milk is a convenient means to estimate trans‐18:1 acid consumption by corresponding populations. Adapted methods (i.e., silver‐ion thin‐layer chromatography, coupled with GLC on long polar capillary columns) allow accurate quantitation of most individual trans‐ 18:1 acids, more particularly of the trans‐Δ16 isomer. This determination, along with a knowledge of the distribution of individual isomers in ruminant fats and partially hydrogenated oils, is a convenient means to estimate the relative contribution of these two dietary sources to the distribution of individual trans‐18:1 isomers in human milk lipids. A comparison of human milk and infant formulas is made with regard to trans‐18:1 acid content and profile. Important differences are noted between data from European countries and from North America.
Cold stability of red palm oleins
Authors: NorAini I. , Hanirah H. , Siew W. L. , Yusoff M. S. A. 
Published: May 2007

AbstractCold stability of crude and refined red palm oleins was investigated. Single‐ and double‐fractionated crude as well as refined single‐ and double‐fractionated red palm oleins were stable against crystallization for more than 1 h but less than 2 h, whereas commercial red palm oleins remained stable for more than 5 h at 5°C. At 20°C, refined red palm oleins had better resistance to crystallization than crude palm oleins. Red palm oleins with lower amounts of saturated fatty acids (C16:0 and C18:0), lower levels of POP and POS triacylglycerols, and lower cloud points have increased resistance to crystallization and result in better cold stability.
Determination of copper, lead, and nickel in edible oils by plasma and furnace atomic spectroscopies
Authors: Allen Lori B. , Siitonen Paul H. , Thompson Harold C. 
Published: May 2007

AbstractAn atmospheric pressure microwave digestion procedure is described for the determination of copper, lead, and nickel in edible oils. The digestion procedure is compatible with either inductively coupled plasma atomic emission spectrometry (ICP‐AES) or graphite furnace atomic absorption spectrometry (GFAAS). Instrument conditions are specified to allow the simultaneous determination of all three metals for each sample introduction. Method detection limits were element‐specific but equal to or less than 50 ng/g with ICP‐AES and 30 ng/g with GFAAS. Results from spike and recovery experiments at levels of 50, 100, and 200 ng/g are reported for corn and soybean oil. For soybean oil, recoveries at 100 ng/g were 90, 100, and 106%, respectively, for copper, lead, and nickel with ICP‐AES, and 89, 106, and 96%, respectively, with GFAAS. Recoveries for corn oil spiked at 100 ng/g were 93, 95, and 103%, respectively, for copper, lead, and nickel with ICP‐AES, and 90, 117, and 100%, respectively, with GFAAS. Day‐to‐day reproducibility was demonstrated by similar method recoveries and reproducibilities in independent analysis of two canola oil sample sets that were spiked at 100 ng/g.
Physical and chemical properties of trans‐free fats produced by chemical interesterification of vegetable oil blends
Authors: Petrauskaite V. , De Greyt W. , Kellens M. , Huyghebaert A. 
Published: May 2007

AbstractFat blends, formulated by mixing a highly saturated fat (palm stearin or fully hydrogenated soybean oil) with a native vegetable oil (soybean oil) in different ratios from 10:90 to 75:25 (wt%), were subjected to chemical interesterification reactions on laboratory scale (0.2% sodium methoxide catalyst, time=90 min, temperature=90°C). Starting and interesterified blends were investigated for triglyceride composition, solid fat content, free fatty acid content, and trans fatty acid (TFA) levels. Obtained values were compared to those of low‐ and high‐trans commercial food fats. The interesterified blends with 30–50% of hard stock had plasticity curves in the range of commercial shortenings and stick‐type margarines, while interesterified blends with 20% hard stock were suitable for use in soft tubtype margarines. Confectionery fat basestocks could be prepared from interesterified fat blends with 40% palm stearin or 25% fully hydrogenated soybean oil. TFA levels of interesterified blends were low (0.1%) compared to 1.3–12.1% in commercial food fats.
Separation of stigmasta‐3,5‐diene, squalene lsomers, and wax esters from olive oils by single high‐performance liquid chromatography run
Authors: Amelio Mauro , Rizzo Renzo , Varazini Flavio 
Published: May 2007

AbstractTo ascertain the authenticity of olive oils, the European Community Regulation requires the stigmasta‐3,5‐diene and wax ester contents to be determined. The official methods are time‐consuming and not suitable for many daily analyses, as quality‐control laboratories need. A method is presented here that allows single high‐performance liquid chromatography separation of stigmasta‐3,5‐diene and wax esters, as well as of the squalene isomers, which give further information on the oil’s authenticity. For stigmasta‐3,5‐diene, the comparison with results obtained with the official method is good. Also for wax esters, the agreement was good, even if they were compared with results obtained from a quicker method as reliable as the official one. The possibility of separating the squalene isomers also at the same time makes the proposed method more advantageous. On the whole, the method, which is suggested for routine and quick screening but not for the exact evaluation of the analyte contents, seems to be a convenient choice for ascertaining on a daily basis the samples’ legal compliance (i.e., whether the analyte content is or is not below the legal value).
Bleaching kinetics of sunflowerseed oil
Authors: Topallar Hüseyin 
Published: May 2007

AbstractThe bleaching process for sunflowerseed oil follows a rate formula, log (A/A0)=−κ, according to absorbance measurements. The dark color of crude oil converts to a light color as the absorbance value decreases. The activation energy Ea was calculated from the Arrhenius equation as 3 kJ, and other activation thermodynamic parameters were determined as ΔS⊄=−4.4 J K−1, ΔH⊄=−31.2 J mol−1, and ΔG⊄=1.6 kJ mol−1. The study showed that the bleaching process was exothermic, presented a decrease of entropy, and was a nonspontaneous process during activation.
Fluorometric detection of interaction between lipase and glyceride
Authors: Tsuzuki Wakako , Kobayashi Shoichi , Suzuki Tateo 
Published: May 2007

AbstractPreviously, we devised the efficient modification of lipase, which can be dissolved and still maintain its activity in organic solvents. In this work, the fluorescence of the modified lipase could be detected in chloroform. When glycerides were added to the modified lipase solution, the intrinsic tryptophan fluorescence of the modified lipase decreased, which suggests that the environment of the tryptophan residue was affected by the substrate. The interaction between the modified lipase and glyceride was studied kinetically in terms of fluorescence intensity of the tryptophan residue. Because glyceride is not subject to hydrolysis in nonaqueous solution, the dissociation constant of the enzyme‐substrate complex could be determined. Thus, insight into the direct interaction between enzyme and substrate provided some structural information regarding the active site of lipase.
Separation of tripalmitin from its hydrolysis products by simple isocratic reversed‐phase high‐performance liquid chromatography
Authors: Hampson J. W. , Foglia T. A. 
Published: May 2007

AbstractAn isocratic reversed‐phase high‐performance liquid‐chromatographic method was developed for monitoring the lipase‐catalyzed hydrolysis of solid triglycerides in supercritical carbon dioxide. The reaction products obtained consist of free fatty acids, monoglycerides, diglycerides, and unreacted triglycerides. For the method, developed with tripalmitin, a mobile phase of acetonitrile/chloroform/acetic acid (50:50:1, vol/vol/vol), a C18 column, and refractive index detection were used. Analysis time is 7 min. Response factors were determined for each neutral lipid class, which permitted quantitation of the hydrolysis product mixture.
Trans‐free vanaspati containing ternary blends of palm oil‐palm stearin‐palm olein and palm oil‐palm stearin‐palm kernel olein
Authors: Nor Aini I. , Che Maimon C. H. , Hanirah H. , Zawiah S. , Che Man Y. B. 
Published: May 2007

AbstractFour samples of trans‐free vanaspati were made using palm oil‐palm stearin‐palm olein (PO‐POs‐POo) blends (set A) and another four samples (set B) using palm oil‐palm stearin‐palm kernel olein (PO‐POs‐PKOo). Palm stearin iodine value [iodine value (IV), 30] and soft palm stearin (IV, 44) were used in this study. The products were evaluated for their physical and chemical properties. It was observed that most of the vanaspati were granular (grainy) and had a shiny appearance. Chemical analyses indicated that vanaspati consisting of PO‐POs‐POo had higher IV (47.7–52.4) than the PO‐POs‐PKOo vanaspati (37.5–47.3). The higher IV demonstrated by set A samples was due to their higher content of unsaturated fatty acids, 46.0–50.0% compared to 36.6–45.0% in set B. Decreasing the amount of palm oil while increasing palm stearin in the formulations resulted in higher slip melting points and higher yield values. Eutectic interaction was observed in PO‐POs‐PKOo blends. The β′ crystalline form was predominent in PO‐POs‐POo samples (set A). One formulation in set B exhibited β crystallinity. From the differential scanning calorimetry thermograms, samples in set B showed a high peak at the low‐melting region as well as a high peak at the high‐melting region. In set A, the peak at the low‐melting region was relatively lower.
Enzymatic synthesis of fatty alcohol esters by alcoholysis
Authors: De B. K. , Bhattacharyya D. K. , Bandhu C. 
Published: May 2007

AbstractLipase‐catalyzed conversions of some minor oils and fats like mowrah (Madhuca latifolia), mango (Mangifera indica) kernel, and sal (Shorea robusta) fats into low, medium, and high molecular weight alcohol esters have been investigated. In solvent‐free medium, alcoholysis of the above‐mentioned fats with 10% (w/w) Mucor miehei lipase produced alcohol esters in good yield. The percentage molar conversions of C4, C8, C10, C12, C14, C16, C18, and C18:1 alcohols into corresponding alcohol esters ranged from 86.8 to 99.2, while the percentage molar conversions on the basis of oil were in the range of 108.0 to 123.5.
Modulated temperature differential scanning calorimetry for examination of tristearin polymorphism: 2. Isothermal crystallization of metastable forms
Authors: Singh Satish K. , Jalali Ali Fathe , Aldén Maggie 
Published: May 2007

AbstractThe transformations of tristearin were examined by modulated temperature differential scanning calorimetry (MTDSC) in order to examine the utility of this technique. Tristearin has been used as a model polymorphic system, showing metastable phases and complicated transformation routes occuring at relatively slow rates. The β′‐forms generated by thermal treatment under modulation do not differ significantly from those generated by the corresponding treatment without modulation. While the total heat flow thermograms are similar, the deconvoluted reversing component shows that annealing, especially at 63°C, has a significant effect on the crystal size and perfection of the solid phases formed. MTDSC also enables the melting of β′ to be separated from the simultaneous crystallization of the β form as evidenced in the cp component. Quantitative interpretations about such systems cannot be drawn from MTDSC at this point in time.
Argan oil‐in‐water emulsions: Preparation and stabilization
Authors: Yaghmur A. , Aserin A. , Mizrahi Y. , Nerd A. , Garti N. 
Published: May 2007

AbstractWe prepared stable oil‐in‐water emulsions of argan oil with two different types of mixtures of nonionic emulsifiers. Three different types of oil (Israeli argan oil, Moroccan argan oil, and soybean oil) were emulsified with mixtures of Span 80 and Tween 80. The optimum HLB value for argon oil was 11.0 (±1.0). The argan oil‐in‐water emulsions were stable for more than 5 mon at 25°C. Synergistic effects were found in enhancing stability of emulsions prepared with sucrose monostearate. The origin of the oil and the internal content of natural emulsifiers, such as monoglycerides and phospholipids, have a profound influence on its interfacial properties and on the stability of the argan oil‐in‐water emulsions.
Raffinose content may influence cottonseed susceptibility to aflatoxin contamination
Authors: Mellon Jay E. , Cotty Peter J. 
Published: May 2007

AbstractThe effect of the cotton storage trisaccharide raffinose and cottonseed storage protein (CSP) in combination on aflatoxin production by Aspergillus flavus was investigated. The ability of ground whole cottonseed and water‐extracted cottonseed meal to support fungal biosynthesis of aflatoxin also was assessed in vitro. Dose response data showed that utilization of raffinose as a sole carbon source supported growth and aflatoxin production by A. flavus. When raffinose was a carbon source and CSP was the sole nitrogen source, aflatoxin levels were stimulated up to fourfold above those in raffinose reference media. Results with ground whole cottonseed as a sole carbon/nitrogen source demonstrated the capacity for aflatoxin production in A. flavus cultures. Lipid extraction of ground whole seed severely reduced aflatoxigenesis potential; however, lipid extraction followed by water extraction of ground whole seed restored much of the aflatoxin biosynthetic potential, suggesting the presence of a water soluble inhibitory factor. Accessible carbon appeared to be the limiting resource in water‐extracted meal, as a raffinose supplement stimulated aflatoxin production. Either cottonseed storage lipid or raffinose was capable of providing accessible carbon to A. flavus. Raffinose and CSP in developing and mature cottonseed may predispose seed to potentially high levels of aflatoxin contamination by A. flavus upon seed infection.
C‐terminal His‐tagging results in substrate specificity changes of the thioesterase I from Escherichia coli
Authors: Lee Ya‐Lin , Su May‐Shyuan , Huang Tai‐Huang , Shaw Jei‐Fu 
Published: May 2007

AbstractThe biochemical properties of Escherichia coli thioesterase I, His‐tagged (HT) on the C‐terminal, were systematically analyzed and compared with that without the His‐tag (WT). These two types of enzymes exhibit similar optimal temperature and pH dependence, but subtle differences were detected. Kinetic studies revealed that the kcar/JKm values of the HT enzyme for the substrates palmitoyl‐CoA and p‐nitrophenyl dodecanoate were 36‐ and 10‐fold lower than those of the WT, respectively. In contrast, HT had a fivefold increased catalytic efficiency for p‐nitrophenyl acetate, and up to fourfold increases toward phenylalanine‐ and tyrosine‐derived ester substrates, l‐NBPNPE (N‐carbobenzoxy‐l‐phenylalanine p‐nitrophenyl ester) and l‐NBTNPE (N‐carbobenzoxyl‐l‐tyrosine p‐nitrophenyl ester), respectively. For l‐NBPNPE and l‐NBTNPE, the increases were attributed to the higher kcat values with little changes in Km, whereas the increase for p‐nitrophenyl acetate was mainly attributed to the lower Km value. It is concluded that addition of six hydrophilic histidine residues on the C‐terminus resulted in a change in substrate specificity of E. coli thioesterase I toward more hydrophilic substrates.