bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of bile salts with gastrointestinal mucins
Authors: Wiedmann Timothy Scott , Liang Wei , Herrington Heather
Published: November 2006

The properties of three mucins were examined to identify the structural features responsible for their functional differences. Bovine submaxillary mucin (BSM), porcine gastric mucin (PGM), and rat intestinal mucin (RIM) were each characterized, and high carbohydrate contents were found for RIM and PGM. The amino acid compositions were typical of mucin glycoproteins, with over half comprising small, neutral amino acids. Thereafter, each mucin was equilibrated with three different series of concentrations of the bile salts sodium taurocholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate. Following multiple centrifugations, the supernatant and mucin pellet concentrations of the bile salts were measured. The bile salt pellet concentration was plotted as a function of supernatant concentration, and from the slopes, the excluded volumes were calculated as 25, 29–44, and 28–55 mL/g for BSM, RIM, and PGM, respectively. The intercepts were 8–10, 2–3, and 1–3 mM for BSM, RIM, and PGM, respectively, which represents an estimate of the bound concentration of bile salt. Differences among the bile salts were observed in the excluded volume and amount bound, but no trends were evident. The bile salts may interact as aggregates with the hydrophobic areas and carbohydrate side chains of the mucins, providing favorable sites for association. The binding at low concentrations with exclusion at high concentrations is significant for modulating the absorption of lipid aggregates from the intestine. Finally, the differences among the mucins reflect the unique structure‐function relationship of these gastrointestinal mucins.
Incorporation of 1‐chlorooctadecane into FA and β‐hydroxy acids of Marinobacter hydrocarbonoclasticus
Authors: Aubert Elisabeth , Metzger Pierre , Largeau Claude
Published: November 2006

The lipids of the gram‐negative marine bacterium Marinobacter hydrocarbonoclasticus, cultivated in synthetic seawater supplemented with 1‐chlorooctadecane as sole source of carbon, were isolated, purified, and their structures determined. Three pools of lipids were isolated according to the sequential procedure used: unbound lipids extracted by organic solvents, ester‐bound lipids released under alkaline conditions, and amide‐bound lipids released by acid hydrolysis. FA isolated from the unbound lipids included ω‐chlorinated (21%, w/w, of this fraction; C16 predominant) and nonchlorinated compounds (22%; w/w, C18 predominant). These acids were accompanied by a high proportion of ω‐chloro‐C18 alcohols (43%, w/w) and a lower amount of ω‐chloro‐β‐hydroxy‐C18,‐C16, and‐C14 acids (5%, w/w). These data, together with the isolation from the culture medium of γ‐butyrolactone, suggested a metabolism of 1‐chlorooctadecane through oxidation into ω‐chloro acid and then the classic β‐oxidation pathway. The analysis of the ester‐bound and amide‐bound lipids revealed that significant amounts of ω‐chloro‐β‐hydroxy C10–C12 acids were incorporated into the lipopolysaccharides of the bacterium. Incorporation of these ω‐chloro‐β‐hydroxy acids into the lipopolysaccharides represents a novel route for chloroalkane assimilation in hydrocarbonoclastic gram‐negative bacteria. The formation of chlorinated hydroxy acids, like the ω‐chloro FA in the cellular lipids, could account for an incomplete mineralization of chloroparaffins in the environment.
Effect of baicalein and acetone extract of Scutellaria baicalensis on canola oil oxidation
Authors: Chen Zhen‐Yu , Su Ya‐Lun , Bi Yu‐Rong , Tsang Suk Ying , Huang Yu
Published: November 2006

There is an increasing interest in natural antioxidants present in traditional Chinese herbal medicines. The present study examined the antioxidant activity of heane, acetone, and methanol extracts, as well as baicalein purified from the dry roots of Scutellaria baicalensis Georgi (common name: Huangqin), in heated canola oil. Oxygen consumption and decreases in linoleic acid linolenic acid content were monitored in canola oil held at 90–93°C. Among the three extracts, the acetone extract was most effective against oxidation of canola oil, followed by the methanol extract of the dry roots. The antioxidant activity of these three extracts correlated well with their content of baicalein, which provided strong protection to canola oil from oxidation. The antioxidant activity of Huangqin acetone extract was dose‐dependent. The acetone extract at 100 ppm or above was even more effective than butylated hydroxytoluene at 200 ppm in protecting canola oil from oxidation. The present results suggest that the acetone extract of these roots should be further explored as a potential source of natural antioxidants for use in the processed foods.
Effect of high‐oleic sunflower seed on the carotenoid stability of ground pepper
Authors: Pérez‐Gálvez A. , Garrido‐Fernández J. , Mínguez‐Mosquera M. I.
Published: November 2006

Mixtures of dehydrated pepper fruit (Capsicum annuum L.) with pepper seed (PS) and with high‐oleic sunflower seed (SFS) in proportions of 0, 20, 30, and 40% (w/w) were subjected to heat degradation to compare the effect of a polyunsaturated medium (PS mixtures) and a monounsaturated medium (SFS mixtures) on the carotenoid fraction. The kinetic study carried out indicates that the carotenoid degradation, in both types of mixture and for all the proportions, fits a first‐order mathematical model. The values of the kinetic constant k in each case and for the stage of commercial usefulness of the paprika, which ends when 50% of its initial coloring power has been lost, indicate that the presence of a higher percentage of seed, either pepper or high‐oleic sunflower, in the mixture means a greater stability of the carotenoid fraction. However the presence of a lipid medium less sensitive to oxidation (SFS mixtures) strengthens this effect, prolonging the stage of practical usefulness of the product, so manufacture of paprika by grinding dehydrated pepper fruit with high‐oleic SFS will provide a product with a longer shelf life. Also the improvement of the natural lipid substrate of the pepper fruit, to delay carotenoid degradation in the end product, is a possible line of investigation.
Synthesis of medium‐chain glycerides using lipase from Candida rugosa
Authors: Wong W. C. , Basri M. , Razak C. N. A. , Salleh A. B.
Published: November 2006

Enzymatic synthesis of medium‐chain glycerides (MCG) from capric acid and glycerol was studied using lipase from Candida rugosa. The effects of various reaction parameters such as time, molar ratio of substrates (mmol capric acid/mmol glycerol), amount of lipase, type of organic solvents, and initial water activity (aw) were studied. The best conditions tested for MCG synthesis at 37°C were, respectively, time, 24 h; molar ratio of substrates, 2.5; and amount of lipase, 100.0 mg. The use of organic solvents greatly influenced the activity of lipase in the synthesis of MCG. Generally, activity of lipase was high in nonpolar solvents with log P values from 3.50 to 4.50, where P is the partition coefficient between water and 1‐octanol. The enzymatic synthesis of MCG was preferably carried out at an initial aw of 0.328, which resulted in maximal yield. Analysis of the products of reaction using gas chromatography showed that lipase from Candida rugosa seemed to produce more dicaprin and tricaprin than monocaprin.
Sunflower protein hydrolysates for dietary treatment of patients with liver failure
Authors: Bautista Juan , Corpas Raquel , Cremades Olga , Hernández‐Pinzón Inmaculada , Ramos Rosa , Villanueva Alvaro , Sánchez‐Vioque Raul , Clemente Alfonso , Pedroche Justo , Vioque Javier , Parrado Juan , Millán Francisco
Published: November 2006

A method is described to obtain hydrolysates with defined characteristics and a high Fischer ratio for patients with liver failure, using sunflower proteins (globulin fraction‐II) as starting material. Protein with a branched chain amino acid (BCAA) concentration of 29.7±1.7% is treated in a first step with immobilized chymotrypsin (raw hydrolysate‐1). Subsequent ultrafiltration (cut‐off 3 kDa) of the hydrolysate gives sunflower protein hydrolysate‐I (SFPH‐I). In a second step, SFPH‐I is treated with immobilized carboxypeptidase‐A at alkaline pH for quasi‐selective removal of aromatic amino acids (AAA). This sequential two‐step process, followed by size exclusion chromatography on a Sephadex G‐15 column, yields a product (SFPH‐II) with a BCAA concentration of 37.4±2.2% and an AAA concentration of 0.5±0.1%, which gives a very high Fischer ratio (≈75). The product, comprising mainly peptides with molecular weights in the range of 3500 to 750 Da and free amino acids, is hypoallergenic and shows no or only a trace of bitterness. Any bitterness can be completely removed by treatment with Flavozyme®, giving a hydrolysate that is composed mainly by tri‐ and dipeptides and free amino acids, and is termed highly hydrolyzed protein hydrolysate (HHPH). Both SFPH‐II and HHPH can be used in enteral, parenteral, and oral nutrition for the treatment of patients with liver failure. This product presents all the conditions required for use in the treatment of patients with liver failure: high content in BCAA and low content in AAA, below 2%, and consequently, a very high Fischer ratio, ≈75.
Enzymatic treatment of rice bran to improve processing
Authors: Hernandez N. , Rodriguez‐Alegría M. E. , Gonzalez F. , Lopez‐Munguia A.
Published: November 2006

A modification of the process of oil extraction from rice bran is proposed, introducing one or two enzymatic reactions previous to solvent extraction. Although a total aqueous enzymatic extraction process did not result in reasonable oil extraction yields, an interesting alternative results from enzymatic reactions previous to solvent extraction or pressing. A thermal treatment of rice bran is first applied to deactivate lipase, but also to gelatinize starch previous to reaction with α‐amylase. This is followed by a saccharifying step with glucoamylase to produce glucose (28 g/100 g of rice bran treated), while the residual paste, 66.7% of the original bran, may be subjected to a proteolytic process for protein extraction or directly treated with the solvent to obtain bran oil. Finally, under the defined extraction conditions using hexane, yields of oil are 5% higher when rice bran has been previously treated with α‐amylase.
Chloroacetoxylation of oleic acid—A kinetic study
Authors: Doulia Danae , Rigas Fotis , Gimouhopoulos Kostantinos
Published: November 2006

The kinetics of the addition reaction of chloroacetic acid to oleic acid (chloroacetoxylation) in the presence of sulfuric acid as a catalyst were investigated. The reactions were carried out at the same concentration of both reactants at various temperatures and catalyst content. The reaction time ranged from 30 min up to 12 h, and the reaction course was observed by determining mainly iodine value, and chlorine content of the oil samples at 30‐min intervals. The experimental data fitted the reversible second‐first order rate equation for bimolecular‐unimolecular type reactions. The reaction constants of the forward and reverse reactions were obtained at temperatures 70 and 80°C. The effect of sulfuric acid content on the reaction constant was investigated at 70 and 80°C.
Grease resistance and mechanical properties of isolated soy protein‐coated paper
Authors: Park Hyun J. , Kim Si H. , Lim Seung T. , Shin Dong H. , Choi Sang Y. , Hwang Keum T.
Published: November 2006

Grease‐resistant paper has been produced by coating paper with isolated soy protein (ISP). Tensile strength (TS) of ISP‐coated paper is 28–30 MPa (between the TS of paper and of ISP film). TS of the ISP‐coated paper (2.3 kg/ream) was highest (36.0 MPa) among other ISP‐coated papers, but elongation (E) of the papers seemed to decrease (though not statistically significantly) as the thickness of the ISP coating increased. ISP‐coated papers were highly impermeable to grease penetration for the first 2 h of the test. The percent stained area of two commercially used polyethylene‐laminated papers was higher than those of ISP‐coated papers. As the amount of plasticizer (a mixture of glycerol and polyethylene glycol) was increased in ISP‐coated paper, the TS decreased and the E increased. When tested, the percent stained areas of the paper containing 0.6 and 1.0 g plasticizer/g protein were lower for the first 2 h than those of the papers containing 0.0 and 0.2 g plasticizer/g protein. Also, percent stained area increased with time. Grease resistance of papers coated with ISP at levels higher than 2.0 kg/ream was equal to or lower than that of polyethylene laminates used for quick‐service restaurant sandwich packaging.
A novel analytical method to detect adulteration of virgin olive oil by other oils
Authors: Mavromoustakos T. , Zervou M. , Bonas G. , Kolocouris A. , Petrakis P.
Published: November 2006

The present study focuses on the olefinic region of the 13C nuclear magnetic resonance (13C NMR) spectrum of virgin olive oil which shows 12 peaks resonating between 127.5 and 130 ppm. These peaks are assigned to the most abundant unsaturated fatty acid moieties of the olive oil, oleic and linoleic acids, which are present in α and β positions of the glycerol backbone. With the use of an internal reference pyrazine, the 12 peaks were integrated and their areas were expressed in mmol/g of virgin olive oil. The intensities of the 12 observed peaks were affected when an authentic virgin olive oil was mixed with a seed oil. This observation was used to develop a semiquantitative method to detect adulteration of virgin olive oil by other oils based on 13C NMR spectroscopy.
Saturated fatty acid adsorption by acidified rice hull ash
Authors: Farook Adam , Ravendran Supramaniam
Published: November 2006

Rice hull ash (RHA) was treated with 1.0 M HNO3 (RHA‐A1) and another batch was treated with 14.0 M HNO3 (RHA‐A14). RHA‐A1 and RHA‐A14 had a pH of 6.58 and 6.13, respectively. Adsorption of saturated fatty acids (C8, C10, C12, C14, C16, and C18) was carried out on RHA‐A1 and RHA‐A14 at 32±1°C. The adsorption data conformed to the Langmuir isotherm. The specific surface area of RHA‐A1 was 183.84 m2 g−1 while that of RHA‐A14 was 174.67 m2 g−1. The specific pore volume of RHA‐A1 was 0.216 cm3 g−1 while that of RHA‐A14 was 0.234 cm3 g−1. The acid‐treated ash, RHA‐A14 (qm=0.43±0.03 mmol g−1 where qm is the amount of adsorbate adsorbed to form a monolayer coverage on the ash particles) showed a twofold increase in the adsorption of fatty acid per gram ash compared to RHA‐A1 (qm=0.25±0.03 mmol g−1). The free energy of adsorption, ΔG°ads, was determined to be −7.06±0.10 and −6.75±0.11 kcal mol−1 for RHA‐A1 and RHA‐A14, respectively. The reduced ΔG°ads values observed for RHA‐A14 were attributed to the electrostatic repulsion of the hydrophobic chain of the fatty acid adsorbed on adjacent sites and brought into close proximity of each other. The ΔG°ads values showed that the process of adsorption took place through physisorption on both RHA.
The effects of roasting temperatures on the formation of headspace volatile compounds in perilla seed oil
Authors: Kim Suk Ju , Yoon Hee Nam , Rhee Joon Shick
Published: November 2006

Volatile compounds of perilla seed oils roasted at different temperatures (150–190°C) were analyzed by dynamic headspace gas chromatography‐mass spectrometry. The headspace volatiles in roasted perilla seed oils (RPSO) were composed of thermally produced flavors and compounds originating from the raw perilla seeds. The roasting temperatures significantly affected the production of thermal reaction flavors. Oils from parilla seeds roasted below 170°C had relatively high concentrations of aldehydes, whereas pyrazines and furans were the predominant volatiles above 170°C. In all of the RPSO, the contents of both perilla aldehyde and perilla ketone remained almost constant and might be used to discriminate perilla seed oils from other roasted vegetable seed oils.
Isoflavone content among maturity group 0 to II soybeans
Authors: Wang Chunyang , Sherrard Marci , Pagadala Sudhakar , Wixon Regina , Scott Roy A.
Published: November 2006

This study reports the isoflavone contents of 210 soybean cultivars grown in South Dakota and explores possible relations between isoflavone contents and agronomic characteristics. Total isoflavone contents (normalized) ranged from 1161 to 2743 μg/g. A number of agronomic characteristics were documented for each variety including maturity group, hilum color, disease resistance, seed weight, yield, maturity (in days), and plant height. Varieties in maturity group I had significantly higher total isoflavones when compared to maturity group 0. Hilum color was related to differences in genistin, daidzein, and genistein content. No differences in isoflavone content were observed based on disease resistance profiles. Genistein content was found to be negatively correlated with yield, days of maturity, and plant height. Weak but significant correlations also existed between these agronomic characteristics and other isoflavones.
Enzymatic esterification of dihydroxystearic acid
Authors: Awang R. , Basri M. , Ahmad S. , Salleh A. B.
Published: November 2006

Dihydroxystearic acid (DHSA) ester was synthesized enzymatically to overcome the problems associated with chemical processes. Immobilized enzyme, Lipozyme IM and Novozym 435, were employed as catalysts in the esterification reaction between DHSA and monohydric alcohol. Various factors that may affect the esterification reaction were studied, such as initial water content (aw), organic solvent, substrate concentration and the influence of alcohol chain length. It was found that the percent conversion was higher in organic solvents with log P (the logarithm of the partition coefficient of solvent in octanol/water system) from 2.0 to 4.0. The reaction was not affected by aw from 0.09 to 0.96. Increasing the mole ratio of alcohol to acid above 2.0 did not increase the percent converions of ester. The ester was identified by Fourier transform infrared and 13C nuclear magnetic resonance spectroscopy.
Nucleation kinetics of emulsified triglyceride mixtures
Authors: Kloek William , Walstra Pieter , van Vliet Ton
Published: November 2006

The purpose of this study is to determine character istic nucleation parameters such as the surface free energy for nucleus formation in mixtures of fully hydrogenated palm oil (HP) in sunflower oil (SF). These parameters will be used to model the bulk crystallization kinetics of the same mixtures. This was achieved by determining the crystallization kinetics in emulsified triglyceride mixtures using differential scanning calorimetry, proton nuclear magnetic resonance, and ultrasound velocity measurements. The latter technique appeared to be very sensitive for monitoring the crystallization kinetics of fat dispersions containing triglycerides with a simple phase behavior. Isothermal crystallization of emulsified HP stabilized by sodium caseinate started at 7 K below the α clear point, and the kinetics were best fitted assuming heterogeneous nucleation. Isothermal crystallization of emulsified 10% HP in SF stabilized by caseinate started at 14 K below the α melting point, and the kinetics were best fitted assuming homogeneous nucleation. If the same dispersion was stabilized by Tween 20, crystallization started at 11 K below the α melting point, and the kinetics were fitted best using heterogeneous nucleation. Analysis of the temperature dependency of the fit parameters yielded a surface free energy of a nucleus of about 4 mJ.m−2 in the case of homogeneous nucleation. Pre‐exponential nucleation frequencies indicated that a large proportion of the triglyceride molecule should be in the right conformation to be incorporated in a nucleus.
Trans fatty acid composition and tocopherol content in vegetable oils produced in Mexico
Authors: Medina‐Juárez L. A. , Gámez‐Meza N. , Ortega‐García J. , Noriega‐Rodriguez J. A. , Angulo‐Guerrero O.
Published: November 2006

The purpose of this study was to evaluate the trans fatty acid (TFA) composition and the tocopherol content in vegetable oils produced in Mexico. Sample oils were obtained from 18 different oil refining factories, which represent 72% of the total refineries in Mexico. Fatty acids and TFA isomers were determined by gas chromatography using a 100‐m fused‐silica capillary column (SP‐2560). Tocopherol content was quantified by normal‐phase high‐performance liquid chromatography using an ultraviolet detector and a LiChrosorb Si60 column (25 cm). Results showed that 83% of the samples corresponded to soybean oil. Seventy‐two percent of the oils analyzed showed TFA content higher than 1%. Upon comparing the tocopherol contents in some crude oils to their corresponding deodorized samples, a loss of 40–56% was found. The processing conditions should be carefully evaluated in order to reduce the loss of tocopherols and the formation of TFA during refining.
Acid‐treated soy hull carbon structure and adsorption performance
Authors: Hong Yan , Proctor Andrew , Shultz John
Published: November 2006

The objective of this study was to evaluate the effect of 14 N phosphoric acid and 12 N hydrochloric acid treatments on soy hull carbon structure and adsorption performance. Scanning electron micrographs showed that acid treatments disrupted the carbon structure whereas X‐ray diffraction data indicated that hydrochloric acid had a greater effect than phosphoric acid in creating a more amorphous carbon structure. Both acids significantly reduced carbon pH from 9.8, but hydrochloric acid reduced the pH to a much greater degree (pH 2.77) than phosphoric acid (pH 5.95). Both acids increased the carbon titratable surface charge. The greatest increase was in surface lactone and phenol groups, but increases were also seen in noncarboxylic carbonyls and the generation of carboxyls. Acidified carbon was most effective as a phospholipid adsorbent, and its lower affinity for other oil components may be due to competitive adsorption. Nonacidified carbon and hydrochloric acid‐treated carbon adsorbed most free fatty acids, whereas the nonacidified control and commercial carbon control were most effective at adsorbing peroxides. However, vacuum adsorption conditions alone increased the contents of saturated carbonyls that were probably formed by peroxide cleavage.
Enzymatic resolution of racemic secondary alcohols by lipase B from Candida antarctica
Authors: Patel Ramesh N. , Banerjee Amit , Nanduri Venkata , Goswami Animesh , Comezoglu F. T.
Published: November 2006

Chiral intermediates S‐(+)‐2‐pentanol and S‐(+)‐2‐heptanol were prepared by a lipase‐catalyzed enzymatic resolution proces. Among various lipases evaluated for the stereoselective acylation of racemic alcohols, lipase B from Candida antarctica catalyzed the acylation of the undesired enantiomer of racemic alcohols leaving the desired S‐(+)‐alcohols unreacted. A reaction yield of 43–45% and an enantiomeric excess (e.e.) of >99% were obtained for S‐(+)‐2‐pentanol or S‐(+)‐2‐heptanol when the reaction was carried out using vinyl acetate or succnic anhydride as acylating agent. In an alternative process, an enantioselective hydrolysis of 2‐pentyl acetate was demonstrated using lipase B giving S‐(+)‐2‐pentyl acetate and R‐(−)‐2‐pentanol. A reaction yield of 45% and an e.e. of 98.6% were obtained for S‐(+)‐2‐pentyl acetate.
Site‐directed mutagenesis of a highly active Staphylococcus epidermidis lipase fragment identifies residues essential for catalysis
Authors: Chang Rey‐Chang , Chou Shu‐Jen , Shaw Jei‐Fu
Published: November 2006

A fragment of Staphylococcus epidermidis lipase gene (Lys‐303 to Lys‐688) was inserted into plasmid pET‐20b(+). The resulting C‐terminal His‐tagged recombinant protein (43 kDa) was overexpressed in Escherichia coli BL21(DE3) as a highly active lipase and was purified with nickel‐coupled resin. Putative catalytic sites were determined by site‐directed mutagenesis. Mutant enzymes (S418C and H648K) lost enzyme activities, which strongly suggests that the proposed residues of Ser‐418 and His‐648 are involved in catalysis. Site‐directed mutagenesis showed that in comparison with wild‐type enzyme, the M419A and V649l enzymes showed a 2.0‐ and 4.0‐fold increase in the kcat/Km′ respectively, but the M419l, M419Q, V649A, and V649L variants lost enzyme activities. The wild‐type enzyme and the V649l mutant favored the hydrolysis of p‐nitrophenyl esters of butyrate, but the M419A favored decanoate. The results suggested that the amino acid residues (Met‐419 and Val‐649), following the catalytic triad, could affect the substrate specificity and/or catalytic efficiency.
Identification of diacylglycerols and triacylglycerols in a structured lipid sample by atmospheric pressure chemical ionization liquid chromatography/mass spectrometry
Authors: Mu Huiling , Sillen Henrik , Hiy Carl‐Erik
Published: November 2006

Atmospheric pressure chemical ionization liquid chromatography/mass spectrometry was used in the identification of diacylglycerol and triacylglycerol (TAG) molecular species in a sample of a structured lipid. In the study of acylglycerol standards, the most distinctive differences between the diacylglycerol and TAG molecules were found to be the molecular ion and the relative intensity of monoacylglycerol fragment ions. All saturated TAG ranging from tricaproin to tristearin, and unsaturated TAG including triolein, trilinolein, and trilinolenin, had ammonium adduct molecular ions [M+NH4]+. Protonated molecular ions were also produced for TAG containing unsaturated fatty acids and the intensity increased with increasing unsaturation. Diacylglycerol fragment ions were also formed for TAG. The ammonium adduct molecular ion was the base peak for TAG containing polyunsaturated fatty acids, whereas the diacylglycerol fragment ion was the base peak for TAG containing saturated and monounsaturated medium‐ and long‐chain fatty acids; the relative intensities of the ammonium adduct molecular ions were between 14 and 58%. The most abundant ion for diacylglycerols, however, was the molecular ion [M−17]+, and the relative intensity of the monoacylglycerol fragment ion was also higher than that for TAG. These distinctive differences between the diacylglycerol and TAG spectra were utilized for rapid identification of the acylglycerols in the sample of a structured lipid.
Trans determination of edible oils by fourier transform near‐infrared spectroscopy
Authors: Li Hui , van de Voort F. R. , Ismail A. A. , Sedman J. , Cox R.
Published: November 2006

A generalized partial‐least‐squares calibration for determination of the trans content of edible fats and oils by Fourier transform near‐infrared (FT‐NIR) spectroscopy using 8‐mm disposable glass vials for sample handling and measurement was developed. The trans contents of a broad range of oils were determined using the American Oil Chemists' Society single‐bounce horizontal attenuated total reflectance (SB‐HATR) mid‐infrared spectroscopic procedure, these trans reference data were used in the development of the generalized FT‐NIR calibration. Additional refined and product‐specific calibrations were also developed, and all the calibrations were assessed for their predictive capabilities using two sets of validation samples, one comprising a broad range of oil types and the other restricted to oils with specific characteristics. The FT‐NIR trans predictions obtained using the generalized calibration were in good agreement with the SB‐HATR results; the values were accurate and reproducible to within ±1.1 and ±0.5% trans, respectively, compared to a reproducibility of ±0.40% trans obtained for the SB‐HATR method. The accuracy of the predictions obtained from the generalized FT‐NIR calibration for particular oil types was not significantly improved by supplementing the base training set with samples of these specific types. Calibrating only these oil types did, however, produce a substantial improvement in predictive accuracy, aproaching that of the SB‐HATR method. These product specific calibrations produced serious predictive errors when nonrepresentative samples were analyzed. The incorporation of a supplementary discriminate analysis routine was found to be a powerful safeguard in flagging nonrepresentative samples as outliers and could also be used to select the calibration most appropriate for the characteristics of the sample being analyzed. Overall, it was concluded that FT‐NIR spectroscopy provides a viable alternative to the SB‐HATR/mid‐Fourier transform infrared method for trans determination, making use of more industrially robust instrumentation and equipped with a simpler sample handling system.
Optimization and validation of high‐performance liquid chromatographic method for the determination of dowtherm ATM in edible oils and oleochemicals
Authors: Moh M. H. , Tang T. S. , Tan G. H.
Published: November 2006

A method using high‐performance liquid chromatography and fluorescence detection is optimized and validated for the determination of Dowtherm ATM in spiked oleochemicals and edible oils. The samples are directly injected into a reversed‐phase C18 column, and Dowtherm A is detected using a fluorescence detector set at 247 nm excitation and 310 nm emission wavelengths. The simple isocratic mobile phase used is a mixture of methanol and water (90∶10, vol/vol) at a flow rate of 1 mL/min. The limits of quantitation are from 0.1 to 0.2 μg/g. Mean recoveries ranged from 93.0 to 116% with reproducibilities of 1.29–3.84%. The procedure provides a simple, reliable and sensitive method for determining Dowtherm A residue in oleochemicals and edible oils without prior sample cleanup or extraction.
Enzymatic acidolysis of tristearin with lauric and oleic acids to produce coating lipids
Authors: Sellappan Subramani , Akoh Casimir C.
Published: November 2006

Triacylglycerols with potential for coating application were prepared by acidolysis of tristearin with lauric and oleic acids using Lipozyme IM60 lipase in n‐hexane. The effects of reaction parameters such as time, temperature, substrate mole ratio, water content, enzyme load, and enzyme reuse were studied. Five‐gram scale synthesis was carried out to obtain the melting profile of products by differential scanning calorimetry (DSC). An acceptable melting profile was obtained for the product obtained with a 1∶4∶1 (tristearin/lauric acid/oleic acid) mole ratio of reactants. The DSC melting peak for this product was 31.4°C. Synthesis of 1200 g of this product was carried out at a 1∶4∶1 substrate ratio in a stirred tank batch reactor under optimal conditions. The reaction product, purified by short‐path distillation, was coated onto crackers and studied for its moisture inhibition ability, under water vapor‐saturated atmosphere, in a desiccator over different time intervals. The effectiveness of the synthesized lipid as a coating material was compared against uncoated crackers as a control and with cocoa butter‐coated crackers. The synthesized lipid was better in preventing moisture absorption than cocoa butter.
Optimization of physicochemical changes of palm olein with phytochemical antioxidants during deep‐fat frying
Authors: Jaswir Irwandi , Che Man Yaakob B. , Kitts David D.
Published: November 2006

Response surface methodology (RSM) was used to optimize the amounts of rosemary and sage extracts together with citric acid as synergist antioxidants in stabilizing refined, bleached, and deodorized palm olein during repeated deep‐fat frying of potato chips. For all physicochemical properties studied, these phytochemical antioxidant treatments significantly (P<0.05) reduced the oxidation rate of the oil. During 5 d of frying, anisidine value, peroxide value, free fatty acid, polymer content, color units, viscosity, and absorbances at 232 and 268 nm gradually increased, whereas iodine value and ratio of 18∶2/16∶0 decreased. Further statistical analyses, including coefficient of determination (R2) and probability of F values, indicated that mathematical models for each physicochemical parameter could be developed confidently in this study, with R2 for all parameters greater than 0.90. These results suggested that an optimal mixture of phytochemical antioxidants derived from rosemary and sage together with citric acid could be produced using RSM for stabilizing thermally processed oil. For many physicochemical parameters examined, the use of moderate levels of antioxidants could result in optimal responses.
Use of high‐resolution 13C nuclear magnetic resonance spectroscopy for the screening of virgin olive oils
Authors: Zamora Rosario , Alba Virginia , Hidalgo Francisco J.
Published: November 2006

13C Nuclear magnetic resonance (NMR) spectra of 104 oil samples were obtained and analyzed in order to study the use of this technique for routine screening of virgin olive oils. The oils studied included the following: virgin olive oils from different cultivars and regions of Europe and north Africa, and refined olive, “lampante” olive, refined olive pomace, high‐oleic sunflower, hazelnut, sunflower, corn, soybean, rapeseed, grapeseed, and peanut oils, as well as mixtures of virgin olive oils from different geographical origins and mixtures of 5–50% hazelnut oil in virgin olive oil. The analysis of the spectra allowed us to distinguish among virgin olive oils, oils with a high content of oleic acid, and oils with a high content of linoleic acid, by using stepwise discriminant analysis. This parametric method gave 97.1% correct validated classifications for the oils. In addition, it classified correctly all the hazelnut oil samples and the mixtures of hazelnut oil in virgin olive oil assayed. All of these results suggested that 13C NMR may be used satisfactorily for discriminating some specific groups of oils, but to obtain 100% correct classifications for the different oils and mixtures, more information than that obtained from the direct spectra of the oils is needed.
Thermal gradient deacidification of crude rice bran oil utilizing supercritical carbon dioxide
Authors: Dunford Nurhan Turgut , King Jerry W.
Published: November 2006

The effect of isothermal and temperature gradient operation of a supercritical fluid fractionation column on the composition of rice brain oil (RBO) fractions has been studied. Application of a temperature gradient along the column was found to be beneficial in reducing the triacylglycerol (TAG) lost in the extract fraction. Utilization of higher temperature in the stripping section improved free fatty acid (FFA) removal from crude RBO. FFA acid content of the extract increased, and TAG content decreased with respect to time during the fractionation runs. Increasing the CO2 flow rate from 1.2 to 2 L/min did not affect the extract composition significantly. By using the above approach, it is possible to obtain RBO fractions with similar total sterol ester content [∼23 high‐performance liquid chromatographic area (HPLC) %, ferulic plus fatty acid esters] to that of the commercially available sterol ester‐enriched (ca. 21 HPLC area % fatty acid esters) margarines/spreads.
Change in the natural ratio between chlorophylls and carotenoids in olive fruit during processing for virgin olive oil
Authors: Roca Mar a , nguez‐Mosquera M». Isabel M
Published: November 2006

Different varieties of olives from different sources, harvested in a similar ripeness state, have been characterized by their chlorophyll and carotenoid pigment profile and content. Pigment richness is inherent to the variety and enables great differences or similarities to be established between them. In all the fruits, ripening involves pigment loss, with the disappearance of chlorophylls always being slightly greater than that of carotenoids. However, independently of variety and the different pitment content of the fruits, the ratio between chlorophylls and carotenoids tends to remain more or less constant, within a range of 2.5 to 3.7 mg total chlorophyll/mg total carotenoid. Pigment loss caused by the extraction process is more marked for the chlorophyll fraction than for the carotenoids, changing the ratio in the oil to around one unit, whatever the variety of soruce fruit.
Calcium carbonate catalyzed alcoholysis of fats and oils
Authors: Suppes G. J. , Bockwinkel K. , Lucas S. , Botts J. B. , Mason M. H. , Heppert J. A.
Published: November 2006

Several alcoholysis catalysts, known to be effective for reactions between simple alcohols and soybean oil, were evaluated and found to be ineffective toward alcoholysis of ethylene glycol with soybean oil under traditional reaction conditions. An initial survey of alternative catalysts revealed that organometallic tin complexes were effective but unsatisfactory due to toxicity and difficulty in recovering the catalyst. Satisfactory performance for several alcoholysis reactions was achieved with calcium carbonate catalysts even though at higher temperatures, typically greater than 200°C. Higher reaction temperatures are not considered to be a problem for flow reactors where heat exchangers can be readily used to minimize energy costs. Free fatty acids were esterified by the calcium carbonate and did not appear to inhibit the catalyst. Reaction times of 18 min provided essentially complete conversion. No decrease in the activity of calcium carbonate was observed after weeks of utilization. The robust structure is suitable for use in packed‐bed reactors. The catalyst used for the flow reactors was pulverized limestone. Limestone from two locations was tested and found to be effective. Catalyst removal requires only a screening process at the reactor discharge.
Production of sugar fatty acid estrs by enzymatic esterification in a stirred‐tank membrane reactor: Optimization of parameters by response surface methodology
Authors: Yan Youchun , Bornscheuer Uwe T. , Stadler Gerhard , Lutz‐Wahl Sabine , Reuss Matthias , Schmid Rolf D.
Published: November 2006

6‐O‐β‐D(+)‐Glucose stearate serving as a model product of glucose fatty acid monoesters was synthesized using lipase B from Candiada antarctica (Chirazyme® L‐2) in a mainly solid‐phase system in a stirred‐tank membrane reactor. Esterification was performed in the presence of a small amount of ethyl methylketone (EMK), maintaining a catalytic liquid phase as well as forming an azeotrope with the reaction water. The azeotrope was evaporated and broken by membrane vapor permeation, then the dried EMK was returned to the reaction medium. The process was optimized by response surface methodology based on five major reaction parameters [time (T), substrate ratio (acyl donor to glucose, Sr, temperature (Rt), amount of solvent [solvent to substrates, [w/w], Sa), and enzyme load (El)] varied at three levels, resulting in higher yields. Thus, under optimized conditions [Tr=58 h; Sr=2.7; El=8.9% (w/w); Rt=78°C; Sa=1.9], up to 93% yields of glucose stearate were achieved.
Relationship between characteristics of oil droplets and solidification of thermally treated creams
Authors: Mutoh Taka‐Aki , Nakagawa Shinsuke , Noda Masayuki , Shiinoki Yasuhiko , Matsumura Yasuki
Published: November 2006

The relationship between the characteristics of oil droplets and the change in appearance of cream was investigated. The model creams (40 wt% oil‐in‐water emulsion), similar to commerical products, were prepared with vegetable fat, milk protein, and emulsifier. The thermal treatment, in which the cream was exposed to a certain temperature and subsequently recooled, was performed on the assumption that the temperature was temporarily elevated during transportation and storage of commercial products. Solidification of the cream was observed when it was exposed to a temperature where there was a small percentage in solid fat content (SFC) of fat in oil droplets and recooled, whereas the cream remained in the liquid state when it was exposed to the temperature where SFC was zero and recooled. When the SFC of oil droplets was 0% at the treated temperature, greater supercooling prior to fat crystallization occurred and the crystallization rate after the initial formation of crystals was much higher. On the other hand, the polymorphism of fat in the droplets was not directly affected by the thermal treatment. These results indicate that the crystallization in oil droplets at the heating temperature may be closely connected with the destablization of oil droplets via a partial coalescence mechanism, which will cause the solidification of cream.
Highly selective asymmetric synthesis of 2‐hydroxy fatty acid methyl esters through chiral oxazolidinone carboximides
Authors: Hwang Hong‐Sik , Erhan Sevim Z.
Published: November 2006

Highly selective asymmetric synthesis of 2‐hydroxy fatty acid methyl esters has been accomplioshed through chiral imide enolates. Five chiral oleic acid imides were prepared by reaction of oleioc acid with pivaloyl chloride followed by reaction with five different lithiated chiral oxazolidinones including (R)‐(+)‐4‐benzyl‐2‐, (S)‐(‐)‐4‐benzyl‐2‐, (4R,5S)‐(+)‐4‐methyl‐5‐phenyl‐2‐, (4S,5R)‐(‐)‐4‐methyl‐5‐phenyl‐2‐, and (R)‐(+)‐4‐isopropyl‐2‐oxazolidinones in 88–92% yileds. The chiral imides were reacted with NaN(Me3Si)2 at −78°C to give enolates, which subsequently reacted with 2‐(phenylsulfonyl)‐3‐phenyloxaziridine to give hydroxylated products in 78–83% yields. Methanolysis of the hydroxylated products with magnesium methoxide gave methyl 2‐hydroxyoleate. Enantiomeric excesses (ee) of the products were determined to be very high (98–99% ee) by 1H nuclear magnetic resonance study after esterification of the hydroxy group with (S)‐(+)‐O‐acetylmandelic acid. Enantioselective hydroxylation of other fatty acids including elaidic, petroselinic, vaccenic, and linoleic was evaluated under the similar conditions using (4R, 5S)‐(+)‐4‐methyl‐5‐phenyl‐2‐oxazolidinone as a chiral auxiliary to give 98% ee values for all cases.
Palm oil quality in different packaging materials sensory and physicochemical parameters
Authors: Narasimhan Shanthi , Rajalakshmi D. , Chand Nagin , Mahadeviah B. , Indiramma A. R.
Published: November 2006

Changes in stored palm oil were studied under three conditions in seven different structured film packages. Six chemical parameters including moisture, free fatty acids (FFA), peroxide values (PV), Kreis tintometric and absorbance/transmittance values, and sensory profiling were examined on a set of 13 odor notes at periodic intervals until the end of the shelf life of the oil or the end of 180 d. Correlation among all the parameters was determined. PV showed high correlations with Kreis test values (as absorbance at 547 nm), while Kreis test values correlated with heated oil and rancid and musty odors. The sensory attributes showed poor correlation among themselves indicating their independent identity and justifying their inclusion in the odor profile descriptors. FFA development positively correlated to harsh odor note. Among the sensory attributes of odor, distinct segregation of desirable notes from defective notes was used to classify different quality grades. Correlation between physicochemical and odor profiles of palm oil suggests that the Kreis test as optical density had the potential to predict deterioration in oil quality. Principal component analysis was carried out on 6 chemical parameters, 13 sensory attributes, and 2 physical properties of the films. The total dimensionality was reduced to 16 variables, and the pathway of quality change during oil storage was traced. Damage to oils was more pronounced when they were stored under 30–40% relative humidity (RH) and 45°C, showing a combined effect of moisture and temperature greater than high RH alone (92%), even at lower temperatures of 27°C. The quality deterioration was comparatively less in films containing polyamide as one of the layers, and leakage rates were minimal in films containing ethylene acrylic acid as the sealant layer.
Cocoa butter extender from Simarouba glauca fat
Authors: Jeyarani T. , Reddy S. Yella
Published: November 2006

Simarouba glauca is a rich source of fat, having a melting point of about 29°C and consisting of palmitic (12.5%), stearic (27%) and oleic (56%) as major fatty acids. It consists of about 30% of symmetrical monounsaturated‐type triacylglycerols and appears to be a good source of fat for preparation of cocoa butter (CB) extender. The stearin fraction (35% yield) obtained by solvent fractionation showed an increased supercooling property and a sudden rise in temperature during solidification compared to native fat as shown by cooling curves. The fraction had a narrow melting range and consisted of a high content (66%) of symmetrical monounsaturated‐type triacylglycerols like CB. The fraction was compatible with CB even at 50% substitution. In addition, the fraction did not affect the formation of stable or other polymorphic forms of CB at different tempering conditions. The fraction obtained by dry fractionation also had properties similar to that obtained by solvent fractionation. The conditions of the fractionation determine the yield of stearin, which in turn alters the melting characteristics of the fractions. The stearin obtained after removal of about 60–65% olein was found to be suitable as a CB extender to replace up to 25% of CB in chocolate products.
Effect of tocopherols on the frying stability of regular and modified canola oils
Authors: Normand L. , Eskin N. A. M. , Przybylski R.
Published: November 2006

A study was conducted to compare the relationship between frying stability and levels and degradation rates of tocopherols in regular and three modified canola oils. Oils were heated at 175 ± 2°C for a total of 72 h, with french fries fried intermittently. Frying stability was compared based on the rates of formation of free fatty acids (FFA) and total polar compounds (TPC). Significant differences (P<0.05) were identified between oils using analysis of covariance and t‐tests for multiple comparisons. No significant differences were observed in the rates of FFA formation among the canola oils during frying. Nevertheless, regular canola (RCO) and high‐oleic, low‐linolenic acid canola (HOLLCO) oils produced less FFA compared to higholeic LLCO and HOCO both had significantly (P<0.05) faster rates of TPC formation compared to HOLLCO or RCO. HOLLCO with the highest level of tocopherols (893 mg/kg) exhibited a slow rate of degradation which accounted for a halflife of 48–60 h of frying. RCO, with a lower level of tocopherols (565 mg/kg), however, had the slowest degradation rate with a half‐liofe of >72 h. In contrast, HOCO and LLCO with 601 and 468 mg/kg tocopherols, respectively, both exhibited a half‐life for tocopherols of 3–6 h of frying. An inverse relatioship was observed between TPC formation and the reduction of tocopherol. Thus, the greater frying stability of RCO and HOLLCO appears to be affected far more by the rate of tocopherol degradation than by any changes in fatty acid composition.
Evaluation of cold‐test methods for screening cloudy canola oils
Authors: Botha Ingrid , Mailer Rodney J.
Published: November 2006

Cloudiness in canola (Brassica napus) oil is currently tested using methods that involve cooling the oil samples and observing them for the development of cloudiness. Alternative methods include the use of solvents to increase sensitivity or speed. We compared traditional temperature‐only cold tests and solvent cold tests for canola oils which sediment at room temperature, only while refrigerated, or not at all. All oils tested passed the American Oil Chemists’ Society cold test, and all but one heavily sedimenting oil passed a commercial refiner's cold test. The efficiency of the commercial refiner's test was improved by lowering the temperature from 15 to 7°C. Of the four solvents tested, acetone was the most effective in detecting cloudy oils. The most effective combination was a cold test using 70% cold acetone, observed after 6 h storage in an ice‐water bath.