bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipase‐mediated acidolysis of tristearin with CLA in a packed‐bed reactor: A kinetic study
Authors: Torres Carlos F. , Munir Farida , Lessard Louis P. , Hill Charles G.
Published: November 2006

Solvent‐free acidolysis of tristearin with CLA has been carried out in a packed‐bed reactor. An immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was employed as the biocatalyst. Elevated temperatures (75°C) were utilized to eliminate solid substrates. The reaction kinetics were modeled by using a rate equation of the general Michaelis‐Menten form. Both the extent of incorporation of CLA and the extent to which FFA were released were investigated. Positional analysis of the purified TAG obtained after a pseudo space time of 0.6 h indicated that CLA was preferentially incorporated at the sn‐1,3 positions of the glycerol backbone, although 10% of the sn‐2 positions were occupied by CLA residues. At a pseudo space time of 0.6 h, 38% of the initial CLA was incorporated in acylglycerols; the associated extent of hydrolysis was 8.3%.
Evaluation of fat‐derived aroma compounds in blue cheese by dynamic headspace GC/Olfactometry‐MS
Authors: Qian Michael , Nelson Cara , Bloomer Scott
Published: November 2006

The aroma compounds in Blue cheese were studied with a dynamic headspace‐GC/olfactometry (GC/O‐DH) technique and evaluated by both aroma extract dilution analysis (AEDA) and the Osme technique to identify and assign importance to aroma compounds. AEDA aroma dilution values were obtained by sequential reduction of sample size, and Osme values were obtained based on aroma intensity and duration. The most important compounds contributing to Blue cheese aroma were diacetyl, 2‐methylpropanal, 3‐methylbutanal, ethyl butanoate, ethyl hexanoate, methional, dimethyl trisulfide, 2‐heptanone, and 2‐nonanone. Compounds central to the characteristic Blue cheese aroma and typically derived from milkfat included 2‐heptanone, 2‐nonanone, butanoic acid, hexanoic acid, and ethyl esters. Since the methyl ketones contributed the characteristic Blue cheese aroma, a flavor concentrate enriched in methyl ketones to impart characteristic Blue cheese aroma was synthesized using Penicillium roqueforti spores in a model system. A fivefold enhancement in methyl ketone production was obtained by providing aerobic conditions. The addition of sucrose and serine, compounds known to affect mold spore metabolism, did not enhance methyl ketone production but caused generation of an uncharacteristic fruity, floral aroma.
Functional properties of extruded‐expelled soybean flours from value‐enhanced soybeans
Authors: Heywood A. A. , Myers D. J. , Bailey T. B. , Johnson L. A.
Published: November 2006

The functional properties (protein solubility, emulsification characteristics, foaming characteristics, water‐ and fatbinding capacities) of extruded‐expelled (EE) soy flours originating from six varieties of value‐enhanced soybeans (high‐sucrose, high‐cysteine, low‐linolenic, low‐saturated FA, high‐oleic, and lipoxygenase‐null) and two commodity soybeans were determined. The soy flours varied in protein disperisibility index (PDI) and residual oil (RO), with PDI values ranging from 32 to 50% and RO values ranging from 7.0 to 11.7%. Protein solubility was reduced at pH values near the isoelectric region and was higher at both low and high pH. There were no significant differences for water‐holding capacity, fat‐binding capacity, emulsification activity, or emulsification stability. Only the high‐oleic soy flour had significantly lower emulsification capacity. In general, the PDI and RO values of EE soy flours originating from value‐enhanced and commodity soybeans had the greatest influence on protein functionality. The genetic modifications largely did not affect functional properties.
Countercurrent approach to the enrichment of Δ9c,11t‐and Δ10t,12c‐18:2 isomers by urea complexation
Authors: Ma David W. L. , Field Catherine J. , Clandinin M. T.
Published: November 2006

CLA refers to a group of geometrical and positional isomers of linoleic acid. CLA has been shown to have potentially beneficial effects on cancer, atherosclerosis, and body metabolism in animals. Mixtures containing equal amounts of these isomers are commonly used in many research studies because of their greater availability and lower cost relative to pure isomers. This has hindered progress in elucidating the biological properties of specific isomers and their relevance in animal and human biology. A method was developed that offers a compromise between cost and utility to make available enriched mixtures of either the Δ9c,11t‐ or Δ10t,12c‐18:2 isomers for use in a wide range of experimental applications. A countercurrent approach was developed to separate the Δ9c,11t‐ and Δ10t,12c‐18:2 isomers from an equal mixture of these two isomers by urea complexation. After three successive rounds of complexation using an equal amount of CLA and urea, a fraction enriched in Δ9c,11t‐18:2 containing 42.5 and 17.4% of Δ9c,11t‐and Δ10t,12c‐18:2, respectively, was recovered. After a single round of complexation using 2.5 g urea/g CLA, a fraction enriched in Δ10t,12c‐18:2 was recovered containing 29.7 and 69.1% of Δ9c,11t‐ and Δ10t,12c‐18:2, respectively.
Wax composition of sunflower seed oils
Authors: Carelli Amalia A. , Frizzera Lorna M. , Forbito Pedro R. , Crapiste Guillermo H.
Published: November 2006

Waxes are natural components of sunflower oils, consisting mainly of esters of FA with fatty alcohols, that are partially removed in the winterization process during oil refining. The wax composition of sunflower seed as well as the influence of processing on the oil wax concentration was studied using capillary GLC. Sunflower oils obtained by solvent extraction from whole seed, dehulled seed, and seed hulls were analyzed and compared with commercial crude and refined oils. The main components of crude sunflower oil waxes were esters having carbon atom numbers between 36 and 48, with a high concentration in the C40−C42 fraction. Extracted oils showed higher concentrations of waxes than those obtained by pressing, especially in the higher M.W. fraction, but the wax content was not affected significantly by water degumming. The hull contribution to the sunflower oil wax content was higher than 40 wt%, resulting in 75 wt % in the crystallized fraction. The oil wax content could be reduced appreciably by hexane washing or partial dehulling of the seed. Waxes in dewaxed and refined sunflower oils were mainly constituted by esters containing fewer than 42 carbon atoms, indicating that these were mostly soluble and remained in the oil after processing.
Combustion characteristics of candles made from hydrogenated soybean oil
Authors: Rezaei Karamatollah , Wang Tong , Johnson Lawrence A.
Published: November 2006

Hydrogenated soybean oil, referred to as soywax by candle makers, is a renewable and biodegradable alternative to paraffin wax in candle manufacturing. Soywax was investigated for its tendency to produce soot as well as potentially harmful organic volatiles (acrolein, formaldehyde, and acetaldehyde) during combustion. Beeswax and paraffin candles were used as references. A considerable amount of soot was produced from the combustion of paraffin candles, but little or none was observed from soywax candles. Compared to paraffin candles, soywax candles burned at a significantly slower rate and required less air. Small amounts of formaldehyde were detected and quantified in the fumes of burning paraffin candles. However, formaldehyde, peaks found in the chromatograms of soy‐ and beeswax candles were similar to or slightly higher than that of the blank. Since soywax candles exhibited burning properties similar to those of beeswax candles, soywax shows promise in candle applications.
Rheological properties of cholesterol‐reduced, yolk‐stabilized mayonnaise
Authors: Moros J. E. , Franco J. M. , Gallegos C.
Published: November 2006

The effects of cholesterol on droplet size distribution and rheological properties of cholesterol‐reduced egg yolk‐stabilized emulsions were determined. Oil‐in‐water emulsions were prepared by using spray‐dried eggs submitted to different levels of cholesterol reduction (14–81 wt% of cholesterol removed). Cholesterol was extracted in a modified Jennings apparatus with subcritical CO2 (9°C and 4.66·106 Pa). Oscillatory and steady flow tests, as well as droplet size distribution measurements, were carried out on the cholesterol‐reduced egg yolk‐stabilized emulsions. The rheological parameters increased with the level of cholesterol reduction up to 40–80 wt% for emulsions having the same total amount of egg yolk. Opposite results, however, were obtined with some emulsions stabilized by a highly cholesterol‐reduced (≈80 wt%) egg yolk. These results were explained by taking into account two opposite phenomena: an increase in the concentration of surface‐active agents as cholesterol content decreased, and a lipoprotein structural rearrangement induced by cholesterol removal.
Production of structured TAG rich in 1,3‐dicapryloyl‐2‐γ‐linolenoyl glycerol from borage oil
Authors: Kawashima Akiko , Shimada Yuji , Nagao Toshihiro , Ohara Akihiro , Matsuhisa Tsugio , Sugihara Akio , Tominaga Yoshio
Published: November 2006

γ‐Linolenic acid (GLA) has the physiological functions of modulating immune and inflammatory responses. We produced structured TAG rich in 1,3‐dicapryloyl‐2‐γ‐linolenoyl glycerol (CGC) from GLA‐rich oil (GLA45 oil; GLA content, 45.4 wt%), which was prepared by hydrolysis of borage oil with Candida rugosa lipase having weak activity on GLA. A mixture of GLA45 oil/caprylic acid (CA) (1∶2, w/w) was continuously fed into a fixed‐bed bioreactor (18×180 mm) packed with 15 g immobilized Rhizopus oryzae lipase at 30°C, and a flow rate of 4 g/h. The acidolysis proceeded efficiently, and a significant decrease of lipase activity was not observed in full‐time operation for 1 mon. GLA45 oil contained 10.2 mol% MAG and 27.2 mol% DAG. However, the reaction converted the partial acylglycerols to structured TAG and tricaprylin and produced 44.5 mol% CGC based on the content of total acylglycerols. Not only FFA in the reaction mixture but also part of the tricaprylin and partial acylglycerols were removed by molecular distillation. The distillation resulted in an increase of the CGC content in the purified product to 52.6 mol%. The results showed that CGC‐rich structured TAG can efficiently be produced by a two‐step process comprising selective hydrolysis of borage oil using C. rugosa lipase (first step) and acidolysis of the resulting GLA‐rich oil with CA using immobilized R. oryzae lipase (second step).
Enzymatic acidolysis in hexane to produce n−3 or n−6 FA‐enriched structured lipids from coconut oil: Optimization of reactions by response surface methodology
Authors: Rao Reena , Manohar Balaraman , Sambaiah Kari , Lokesh Belur R.
Published: November 2006

Response surface methodology is a statistical design that helps one to determine optimal conditions for an enzyme‐catalyzed reaction by performing a minimal number of experiments. This methodology was adapted for modifying coconut oil TAG by using lipase‐catalyzed acidolysis in hexane to incorporate n−3 or n−6 PUFA. FFA obtained after hydrolysis of cod liver oil and safflower oil were used as acyl donors. Immobilized lipase, Lipozyme IM60, from Rhizomucor miehei was used for catalyzing the reaction. The reaction conditions—substrate molar ratio, incubation time, and temperature—were optimized. The experimental data were fitted to a response function based on the central composite rotatable design. The optimal conditions generated from models indicated that maximal incorporation of n−3 PUFA occurred at a 1∶4 molar ratio of TAG/FFA when incubation was carried out for 34 h at 54°C. Similarly, maximal incorporation of n−6 FA was predicted at a 1∶3 molar ratio of TAG/FFA when incubated for 48.5 h at 39°C. Experiments conducted at optimized conditions predicted by the equation obtained from response surface methodology yielded structured lipids with 13.65 and 45.5% of n−3 and n−6 FA, respectively. These values agreed well with that predicted by the model. The reactions were also scaled up to 100 g levels in batch reactors with the incorporation level of n−3 and n−6 fatty acids agreeing closely with that observed when the reactions were carried out at lab scale (100 mg). These studies indicated that response surface methodology is a useful tool in predicting the conditions for incorporating desired levels of specific FA during the synthesis of structured lipids.
Synthesis of MAG of CLA with Penicillium camembertii lipase
Authors: Watanabe Yomi , Shimada Yuji , Yamauchi‐Sato Yoshie , Kasai Masaaki , Yamamoto Takaya , Tsutsumi Kentaro , Tominaga Yoshio , Sugihara Akio
Published: November 2006

CLA has various physiological activities, and a FFA mixture containing almost equal amounts of cis‐9,trans‐11 and trans‐10,cis‐12 CLA (named FFA‐CLA) has been commercialized. We attempted to produce MAG of CLA by a two‐step successive reaction. The first step was esterification of FFA‐CLA with glycerol. A mixture of FFA‐CLA/glycerol (1∶5, mol/mol), 2 wt% water, and 200 units/g of Penicillium camembertii mono‐and diacylglycerol lipase was agitated at 30°C to form a homogeneous emulsion. The esterification degree reached 84% after 10 h. To further increase the degree, the reaction was continued with dehydration at 5 mm Hg. The esterification degree reached 95% after 24 h (34 h in total), and the reaction mixture contained 50 wt% MAG and 44 wt% DAG. The second step was glycerolysis of the resulting DAG. The reaction mixture in the first‐step esterification was transferred from the reactor to a beaker and was solidified by vigorous agitation on ice. When the solidified mixture was allowed to stand at 5°C for 15 d, glycerolysis of DAG proceeded successfully, and MAG content in the reaction mixture increased to 88.6 wt%. Hydrolysis of the acylglycerols was not observed during the second reaction. FA composition in the synthesized MAG was completely the same as that in the original FFA‐CLA, showing that Penicillium lipase does not have selectivity toward FA in the FFA‐CLA preparation.
Effect of oxidation under accelerated conditions on fuel properties of methyl soyate (biodiesel)
Authors: Dunn Robert O.
Published: November 2006

Biodiesel derived from transesterification of soybean oil and methanol is an attractive alternative fuel for combustion in direct‐injection compression ignition (diesel) engines. During long‐term storage, oxidation due to contact with air (autoxidation) presents a legitimate concern with respect to maintaining fuel quality of biodiesel. This work examines the effects of oxidation under controlled accelerated conditions on fuel properties of methyl soyate (SME). SME samples from four separate sources with varying storage histories were oxidized at elevated temperature under a 0.5 standard cm3/min air purge and with continuous stirring. Results showed that reaction time significantly affects kinematic viscosity (ν). With respect to increasing reaction temperature, ν, acid value (AV), PV, and specific gravity (SG) increased significantly, whereas cold flow properties were minimally affected for temperatures up to 150°C. Antioxidants TBHQ and α‐tocopherol showed beneficial effects on retarding oxidative degradation of SME under conditions of this study. Results indicated that ν and AV have the best potential as parameters for timely and easy monitoring of biodiesel fuel quality during storage.
Effect of scraped‐surface tube cooler temperatures on the physical properties of palm oil margarine
Authors: Miskandar M. S. , Che Man Y. B. , Yusoff M. S. A. , Abdul Rahman R.
Published: November 2006

The effects of scraped‐surface tube cooler temperatures on the isothermal solid fat content (SFC) of palm oil margarine during processing and on margarine consistency (yield value, g/cm2), SFC, and polymorphic changes in storage were studied. SFC was measured in the mixing tank after leaving the tube cooler and the pin worker. The SFC at the tube cooler exit was proportional to the amount of cooling; a higher SFC was produced by more extreme cooling treatment. The SFC of all margarines were reduced in the pin worker, and the reduction was related to the initial SFC profile of palm oil. Margarine samples were stored at 28°C for 28 d and tested daily. Margarine processed at 25°C in the tube cooler had the highest consistency and the least change in SFC, but by the second week crystals had transformed into the β form. Uniform product consistency and SFC were observed in margarines processed at 20 and 15°C. These margarines retained the β′ crystal form for 3 and 4 wk, respectively. The best palm oil margarine was obtained with a tube cooler temperature of 15°C and a residence time of 1.8 min.
Immersion vs. percolation in the extraction of oil from oleaginous seeds
Authors: Pramparo M. , Gregory S. , Mattea M.
Published: November 2006

The influence of the two contact modes, percolation and immersion, during the extraction of oilseeds by means of a solvent are presented. Experiments were performed in lab‐scale equipment with soybean flakes, arranged in beds that reproduce these two contact modes. The extractions were carried out with hexane at constant temperature. To simulate the performance of shallow‐and deep‐bed extractors, two different bed height/diameter ratios were used. The experimental results are explained in terms of the basic transfer phenomena that occur during extraction. These phenomena are addressed to develop a mathematical model, which is used to simulate extraction under both contact modes. The immersion scheme yielded greater efficiency than the percolation mode to extract soybean flakes for the two bed height/diameter ratios studied. The mathematical model predicts very well the experimental findings. It also predicts the solvent retained by the solid mass after extracting the oil.
Rheological characterization of yellow grease and poultry fat
Authors: Goodrum John W. , Geller Daniel P. , Adams Thomas T.
Published: November 2006

The rheological properties of yellow grease and poultry fat and their liquid density at 25.0°C were experimentally determined. Dynamic viscosities of these industrial recycled fat products were measured for shear rates of 0.65 to 32.34 s−1 at temperatures of 15.6 to 71.1°C. The resulting measurements were fitted to a power law model to obtain values for the consistency coefficient and the flow behavior index. The data was also fit to Andrade's equation to relate viscosity to temperature. These results indicated pseudoplastic flow behavior for both products, with increasing non‐Newtonian behavior at higher temperatures and shear rates.
GC determination of synthetic hydrocarbon‐based thermal heating fluid in vegetable oils
Authors: Mon M. H. , Tang T. S. , Tan G. H.
Published: November 2006

A combination of alumina column chromatography and GC procedures was developed for the determination of synthetic hydrocarbon‐based thermal heating fluid (trademarked as Therminol 55™) in vegetable oils. In each run, 3 g of sample solution was loaded onto the alumina (50 g) column and was eluted with 200 mL hexane. The eluate was then concentrated to 1 mL with the aid of a nitrogen stream prior to GC analysis. The GC chromatogram of the thermal heating fluid was characterized by the presence of a bell‐shaped hump that could not be resolved into individual peaks. The lowest detection limit based on various spiked palm olein samples was 20 μg/g. The CV obtained were 6.5–8.9% for the intra‐day study and 8.1–9.7% for the inter‐day study. Overall recoveries of these samples ranged from 68.0 to 85.7% and the method was found to be good enough for quality control purposes.
Effect of processing conditions on microstructure of milk fat fraction/sunflower oil blends
Authors: Martini S. , Herrera M. L. , Hartel R. W.
Published: November 2006

The effect of processing conditions on the crystallization of blends of a high‐melting milk fat fraction and sunflower oil was investigated. Two cooling rates were selected for all studies: 0.1°C/min (slow rate) and 5.5°C/min (fast rate). Blends were crystallized in two conditions: (i) with agitation in an 80‐mL crystallizer (dynamic), and (ii) on a microscope slide without agitation (static). The selected crystallization temperatures were 25, 30, and 35°C for both cooling rates. Photographs of the development of crystals with time were taken in both static and dynamic conditions, and the crystal size distribution was determined at the moment that the laser signal reached its peak. Photographs showed that when samples were cooled slowly, crystals had a more regular boundary, appeared to be more densely arranged, and were larger. In dynamic conditions, crystal sizes were smaller and the background contained numerous small crystals, which were not found in statically crystallized samples. All images showed that crystals were not single crystals, but grew by accretion.
Monitoring PV in corn and soybean oils by NIR spectroscopy
Authors: Yildiz Gülgün , Wehling Randy L. , Cuppett Susan L.
Published: November 2006

NIR spectroscopy was used successfully in our laboratory to monitor oxidation levels in vegetable oils. Calibration models were developed to measure PV in both soy and corn oils, using partial least squares (PLS) regression and forward stepwise multiple linear regression, from NIR transmission spectra. PV can be measured successfully in both corn and soy oils using a single calibration. The most successful calibration was based on PLS regression of first derivative spectra. When this calibration was applied to validation sample sets containing equal numbers of corn and soy oil samples, with PV ranging from 0 to 20 meq/kg, a correlation coefficient of 0.99 between titration and NIR values was obtained, with a standard error of prediction equal to 0.72 meq/kg. For both types of oil, changes occurred in the 2068 nm region of the NIR spectra as oxidation levels increased. These changes appear to be associated with the formation of hydroperoxides during oxidation of the oils.
FA composition and regiospecific analysis of Acer saccharum (sugar maple tree) and Acer saccharinum (silver maple tree) seed oils
Authors: Destaillats Frédéric , Jean‐Denis Jean B. , Arul Joseph , Wolff Robert L. , Angers Paul
Published: November 2006

GC analysis was performed to determine regiospecific distribution and FA composition in seed oils of the Aceraceae species, Acer saccharum and A. saccharinum. The oil content in the seeds was low at 5.0% in A. saccharum and 5.8% in A. saccharinum, and the main FA were linoleic (30.8 and 29.4%), oleic (21.3 and 27.6%), palmitic (10.1 and 10.5%), and cis‐vaccenic (9.4 and 7.9%) acids, respectively. In addition, both oils contained long‐chain monoenes of the n−9 and n−7 groups, including 11‐eicosenoic, 13‐docosenoic, 15‐tetracosenoic, 13‐eicosenoic, and 15‐docosenoic acids, whereas γ‐linolenic acid accounted for 0.8% of total FA in A. saccharum, and 0.5% in A. saccharinum. Regiospecific analysis, performed using the methodology of dibutyroyl derivatives of MAG, indicated that linoleic, oleic, and linolenic acids were mainly esterified at the internal position of TAG in both seed oils, whereas long‐chain monoenes of the n−7 group were almost exclusively esterified on the external positions.
Effect of oil degradation during frying on the color of fried, battered squid rings
Authors: Baixauli R. , Salvador A. , Fiszman S. M. , Calvo C.
Published: November 2006

Oil degradation caused by the number of fryings performed and the effect of oil degradation on the color of fried battered squid rings were studied. Spectrophotometric techniques with absorbance in the UV and visible ranges, and iodine, peroxide, and acid values were used to determine oil degradation. Determination of various CIELAB parameters in order to study the external color of the fried battered squid rings revealed no differences in color due to the number of fryings. A study of the color of the battered squid rings at various frying times and temperatures showed significant differences for both variables. Although there was some degradation in the oil after 20 fryings, appearing as a slight darkening, it did not affect the final color of the fried, battered squid rings.
Correlation of viscosities of vegetable oil blends with selected esters and hydrocarbons
Authors: Erhan S. Z. , Asadauskas S. , Adhvaryu A.
Published: November 2006

Blending is often used to reduce the viscosity of vegetable oil lubricants. Experimental rheological results were compared with traditional blending charts and calculation methods. Kinematic viscosities of 90% oleic sunflower, canola, and soybean oils blended with adipates, oleates, polyalphaolefins, and mineral oil were determined at 40°C using capillary viscometers. Blending charts related the viscosities to blend composition with 5% inaccuracy compared with more than 10% deviation made by the cubic equation of Kendall and Monroe. Even more accurate and simpler correlations could be derived. A semilog relationship between viscosities and composition was more accurate than a cubic model. Higher accuracy was also achieved when relating viscosities to volume fractions rather than to weight or mole fractions. Mineral oil blends did not follow the observed rules.
Observations on the estimation of scavenging activity of phenolic compounds using rapid 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH•) tests
Authors: Nenadis Nikolaos , Tsimidou Maria
Published: November 2006

Rapid 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH•) tests are often applied to classify the scavenging activity of phenolic compounds (AH). Published analytical protocols differ in more than one experimental condition, and results for the relative order or magnitude of activity are often contradictory. In this work, parameters such as duration of test, [AH]/[DPPH•] molar ratio, and solvent effects were examined and discussed. The test duration and the value of the [AH]/[DPPH•] ratio did not influence the order of activity among tested antioxidants. Ethanol, commonly used as solvent in such tests, was compared with acetonitrile and tert‐butyl alcohol. Solvent properties such as the ability to form hydrogen bonds with the AH seem to influence the level of the relative activity (%RSA). Higher %RSA values were observed in ethanol. The activity of the most polar compounds was affected the most, and in some cases (caffeic, dihydrocaffeic, and rosmarinic acids) the order of activity was changed owing to different kinetics. Standardization of the analytical protocol should include a 20‐min reaction period and a molar ratio that permits attainment of a 60–80% RSA value for the most potent antioxidant. Solvent choice is critical for classifying activity. Safe classification can be based only on results from kinetic studies.
Synthesis of triglyceride estolides from lesquerella and castor oils
Authors: Isbell Terry A. , Cermak Steven C.
Published: November 2006

Triglyceride (TG) estolides were synthesized from the hydroxy moieties of lesquerella and castor oils with oleic acid. Complete esterification of the hydroxy oils was possible when a slight excess of oleic acid was employed (1 to 1.5 mole equivalents). The estolides could be formed in the absence of catalyst at 175 to 250°C under vacuum or a nitrogen atmosphere. The optimal reaction conditions were found to be under vacuum at 200°C for 12 h for lesquerella and 24 h for castor oil. The lesquerella esterification reaction was completed in half the time of the for castor and with lower equivalents of oleic acid due to the difunctional hydroxy nature of lesquerella TG compared to the trifunctional nature of castor TG. Interesterification or dehydration of the resulting estolides to conjugated FA was not a significant side reaction, with only a slight amount of dehydration occurring at the highest temperature studied, 250°C. Use of a mineral‐or Lewis‐acid catalyst increased the rate of TG‐estolide formation at 75°C but resulted in the formation of a dark oil, and the reaction did not go to completion in 24 h. Estolide numbers (i.e., degree of estolide formation) for the reaction and characterization of the products were made by 1H NMR and 13C NMR. The decrease in the hydroxy methine signal at 3.55 ppm was used to quantify the degree of esterification by comparing this integral to the integral of the alpha methylene protons on the glycerine at 4.28 and 4.13 ppm.
Concentration of sterols and tocopherols from olive oil with supercritical carbon dioxide
Authors: Ibáñez Elena , Hurtado Benavides Andrés M. , Señoráns Francisco J. , Reglero Guillermo
Published: November 2006

A process based on the use of a semicontinuous countercurrent supercritical fluid extraction has been developed to isolate and concentrate minor compounds, such as sterols and tocopherols, from olive oil. In the present work, an evaluation of the efficiency of different random packing materials (Raschig rings, Dixon rings, Fenske rings, and glass beads) to selectively separate sterols and tocopherols from olive oil has been performed. Parameters such as recovery, enrichment, and selectivity vs. TG are discussed. Considering the importance of supercritical fluid extraction as a clean processing technology and the interest in minor compounds with nutraceutical properties from olive oil, the process studied represents an alternative to the reuse of low‐quality olive oil to extract high added‐value products.
Microwave‐assisted catfish liver oil extraction and FA analysis
Authors: Sathivel Subramaniam , Prinyawiwatkul Witoon , King Joan M. , Grimm Casey C. , Lloyd Steven
Published: November 2006

FA profiles of catfish liver oils were analyzed after microwave‐assisted (without solvent extraction) and/or conventional (with solvent extraction) preparation methods. Microwave heating of the smaples was performed at 100, 80, 60, or 40% power at 1,000 W and 2,450 MHz, each for 80, 60, 40, or 20 s. Significant differences in the content of recovered FA were observed among the microwave‐heated samples, except for C20∶0 and C20∶4. Recovery of C16∶0, C20∶0, and C20∶4 from the samples analyzed by the microwave‐assisted method was lower than that of the samples analyzed by the conventional method. Much greater recovery was observed for C18∶1, C18∶2, and C22∶6; however, the recovery was not different from or was only slightly lower than that of the conventional method when microwave heating was set at 40% power for 20 s. This was also observed for the total unsaturated or saturated FA. Compared to other microwave treatments, heating at 100% power for 80 s yielded the greatest recovery of C14∶0, C18∶0, C18∶1, C18∶2, C18∶3, C20∶1, C20∶2, and C22∶6.
Characterization of a double emulsion system (oil‐in‐water‐in‐oil emulsion) with low solid fats: Microstructure
Authors: Jahaniaval Firouz , Kakuda Yukio , Abraham Varghese
Published: November 2006

A double emulsion system [oil‐in‐water‐in‐oil (O/W/O)] with 16.3% (w/w) water and 83% (w/w) oil was prepared and stabilized using a novel method of mixing two oil‐in‐water (O/W) emulsions together. The first emulsion consisted of 85% (w/w) liquid canola oil, 14.4%(w/w) water, 0.5% (w/w) sodium caseinate, and 0.1% (w/w) lecithin and the second emulsion contained 73% (w/w) canola oil, 8% (w/w) palm‐cotton stearin (50∶50), 0.2% (w/w) lecithin, 18.2% (w/w) water, and 0.6% (w/w) sodium caseinate. Mixing the two emulsions (50∶50) by weight produced a product with 79% (w/w) liquid canola oil and 4% (w/w) palm‐cotton stearin. The two O/W emulsions were prepared separately at 50°C, mixed together at 45°C for 2–5 min, and then supercooled in a −5°C ice/salt bath while mixing at low shear rates (2,000–3,000 rpm). Under supercooling conditions the fat globules in the second emulsion (containing liquid oil and stearin) began to break down as a result of fat crystal growth and shearing action and release plastic fat. During this stage, the continuous aqueous phase underwent a phase transition and the emulsion viscosity dropped from 37,000–50,000 to 250 cP. The released plastic fat continued to harden as the temperature dropped and stabilized the first O/W emulsion (containing only liquid oil). The low shear rate mixing was stopped when the temperature dropped below 15°C and before the O/W/O emulsion hardens. Microstructural analysis of the first emulsion before and after supercooling showed essentially intact fat globules. The microstructure of the second emulsion before supercooling showed the same intact globules as the first emulsion, but after supercooling, an amorphous mass with only a few intact globules was seen. By mixing the two emulsions together and supercooling, a stable O/W/O emulsion was formed with plastic fat as the continuous phase and the first O/W emulsion as the dispersed phase.
Enzymatic fractionation and enrichment of n−9 PUFA
Authors: Shimada Yuji , Watanabe Yomi , Kawashima Akiko , Akimoto Kengo , Fujikawa Shigeaki , Tominaga Yoshio , Sugihara Akio
Published: November 2006

A single‐cell oil from a Mortierella alpina mutant (TGM17 oil) contains n−9 PUFA: 14.3 wt% 6,9‐octadecadienoic acid (18∶2n−9; n−9 LnA) and 17.1 wt% Mead acid (20∶3n−9; MA). Lipase screening indicated that Pseudomonas aeruginosa lipase acted strongly on n−9 LnA and weakly on MA, and Candida rugosa lipase acted weakly on the two PUFA. Hence, fractionation and enrichment of the two FA were conducted with the lipases. The first step was selective hydrolysis of IGM17 oil with P. aeruginosa lipase. The hydrolysis fractionated the oil into FFA containing 20.4 wt% n−9 LnA and 6.3 wt% MA, and acylglycerols containing 10.7 wt% n−9 LnA and 23.7 wt% MA. The FFA fraction was used for preparation of n−9 LnA‐rich FFA. After removal of saturated FA, the FFA were esterified with lauryl alcohol (LauOH) using C. rugosa lipase. Two selective esterifications increased the n−9 LnA content to 54.0 wt% with 38.2% recovery of the initial content of TGM17 oil. The acylglycerol fraction obtained in the hydrolysis with P. aeruginosa lipase was used for preparation of MA‐rich FFA. The acylglycerol fraction was hydrolyzed under alkaline conditions, and saturated FA were eliminated by urea adduct fractionation. Two selective esterifications of the FFA with LauOH increased the MA content to 60.2 wt% with 53.5% recovery. Thus, the two‐step enzymatic process was effective for fractionation and enrichment of n−9 LnA and MA.
Protein solubility characteristics of commercial soy protein products
Authors: Lee K. H. , Ryu H. S. , Rhee K. C.
Published: November 2006

Solubility characteristics of commerical soy protein products (flours, concentrates, and isolates) were determined under various conditions. From the solubility profiles at various pH values and NaCl concentrations, soy protein isolates can be divided into three groups. One group had high solubility near the pl. Another group had low solubility near the pl, but high solubility at pH 11. The third group had low solubility even at pH 11. Except for the hydrolyzed products, the protein solubilities of the soy protein products at various salt concentrations were very low. Temperature did not significantly affect the protein solubility, although a few products showed more than a 20% increase at temperatures >50°C. Soy protein concentrates and soy protein isolates showed similar solubility profiles. The proteins in all commercial products (except flours) tested were denatured, as evident from the solubility profiles in the presence of salt and the enthalpy values from DSC.
Monitoring milk fat fractionation: Filtration properties and crystallization kinetics
Authors: Vanhoutte Bert , Dewettinck Koen , Vanlerberghe Brecht , Huyghebaert André
Published: November 2006

The effect of fractionation temperature, residence time, and agitation rate on the chemical composition of the stearin and olein milk fat fractions was studied. During fractionation, filtration properties of the crystal suspension were monitored; crystallization kinetics was determined by 1H NMR. Higher fractionation temperatures result in a lower stearin yield, more oil entrapment, and a lower final solid fat content of the crystal suspension. On the other hand, the chemical composition of the resulting fractions is not influenced. Longer residence times lead to longer filtration times and lower oil entrapment, whereas the yield is not affected. Longer residence times induced lower growth rates, but chemical composition is not influenced. Agitation rates varying from 10 to 15 rpm have no influence on the chemical composition of stearin and olein milk fat fractions. Higher agitation rates decrease the filtration quality and increase stearin yield, causing a softer stearin. In designing and monitoring milk fat fractionation, filtration experiments and the assessment of crystallization kinetics are valuable techniques, but compositional chemical analysis is not favorable.
Identification and quantification of neuroactive N‐acylethanolamines in cottonseed processing fractions
Authors: Chapman Kent D. , Venables Barney J. , Dian Emese E. , Gross Guenter W.
Published: November 2006

N‐Acylethanolamines (NAE) include lipid species that have been identified as potent endocannabinoid mediators in mammalian physiology. Here we have isolated, identified, and quantified the NAE naturally present in cottonseed refining fractions. Among the fractions examined, NAE were most prevalent in finished meal, totaling approximately 8.5 μg/g fresh weight. These NAE were identified by GC‐MS as ethanolamides of myristic (14∶0), palmitic (16∶0), stearic (18∶0), oleic (18∶1), and linoleic (18∶2) acids, with NAE18∶2 and NAE16∶0 being the most abundant. NAE were not detected in refined, bleached, and deodorized oil, although they were present in less‐purified oil fractions. At micromolar concentrations, both NAE18∶2 and NAE16∶0 exhibited neuromodulatory activities in murine neuronal networks cultured and evaluated on microelectrode arrays. It follows that oilseed processing fractions may represent a novel, natural source of bioactive NAE.
Enzymatic conversion of steryl esters to free sterols
Authors: Shimada Yuji , Nagao Toshihiro , Watanabe Youichi , Takagi Yoshiaki , Sugihara Akio
Published: November 2006

Conversion 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

Six 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

Both 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

Tocopherols 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

Structure‐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

Maillard 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

We 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

Margarines 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.