bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipase PS‐catalyzed transesterification of citronellyl butyrate and geranyl caproate: Effect of reaction parameters
Authors: Yee Lisa N. , Akoh Casimir C. , Phillips Robert S.
Published: May 2007

Pseudomonas sp. lipase PS was immobilized by adsorption and tested for its ability to catalyze the synthesis of citronellyl butyrate and geranyl caproate by transesterification in n‐hexane. The reaction parameters investigated were: enzyme load, effect of substrate concentration, added water, temperature, time course, organic solvent, pH memory, and enzyme reuse. Yields as high as 96 and 99% were obtained for citronellyl butyrate and geranyl caproate, respectively, with 300 units (approx. 15% w/w of reactants) of lipase PS. Increasing amounts of terpene alcohol inhibited lipase activity, while excess acyl donor (triacylglycerol) concentration enhanced ester production. Optimal yields were obtained at temperatures from 30–50°C after 24‐h incubation time. Yields of 90 and 99% were obtained for citronellyl and geranyl esters, respectively, with 2% added water. Solvents with log P values ≥ 2.5 showed the highest conversion yields. pH 7 and 6–8 seemed to be ideal for citronellyl butyrate and geraniol caproate, respectively. The lipase remained active after reusing 12 times.
Enzymatic modification of triolein: Incorporation of caproic and butyric acids to produce reduced‐calorie structured lipids
Authors: Fomuso Lydia B. , Akoh Casimir C.
Published: May 2007

Lipase‐catalyzed acidolysis of triolein with caproic and butyric acids was performed to produce reduced‐calorie structured lipids (SL). The SL were obtained by incubating a 1:4:4 mole ratio of triolein, caproic acid, and butyric acid, respectively, with 10% of lipase (w/w of total substrates) in 1.5 mL hexane at 55°C for 24 h. Of nine commercially avaialble lipases screened, IM60, which contains the lipase from Rhizomucor miehei, was the most effective and produced 13 mol% unreacted triolein, 49% disubstituted, and 38% monosubstituted triacylglycerols that contained short‐chain fatty acids. The products were analyzed by reverse‐phase high performance liquid chromatography with an evaporative light‐scattering detector. Reaction parameters studied included time course, temperature, enzyme load, and substrate mole ratio. The yields obtained demonstrate that a structured lipid with long‐chain and short‐chain fatty acids can be synthesized by using IM60 lipase in organic medium.
Nondestructive single‐seed oil determination of meadowfoam by near‐infrared transmission spectroscopy
Authors: Patrick Brett E. , Jolliff Gary D.
Published: May 2007

Near‐infrared transmission spectroscopy (NITS) was explored for single‐seed oil determination of meadowfoam. Two calibration sets were determined by principle component analysis of recorded spectra. Nuclear magnetic resonance (NMR) spectroscopy was used for oil content determination. The calibrations had standard errors of cross‐validation of 3.6 and 4.4%, respectively, with an oil content ranging from 0.8 to 45.7%. This error is similar to that reported for NITS of single maize kernels, relative to the respective oil content ranges. Although not as accurate as NMR spectroscopy, NITS does provide a fast, efficient, and nondestructive method of predicting oil content of individual meadowfoam seeds.
Analysis of seed oil from ricinus communis and dimorphoteca pluvialis by gas and supercritical fluid chromatography
Authors: Borch‐Jensen Christina , Jensen Benny , Mathiasen Kim , Mollerup Jørgen
Published: May 2007

The seed oils from Dimorphoteca pluvialis and Ricinus communis contain hydroxy fatty acids. Dimorphoteca pluvialis contains Δ‐9‐hydroxy‐10t, 12t‐octadecadienoic acid (dimorphecolic acid) and R. communis contains Δ‐12‐hydroxy‐9c‐octadecenoic acid (ricinoleic acid). The oils were derivatized and analyzed to determine the content of hydroxy fatty acids. The trimethylsilyl fatty acid methyl ester (TMS‐FAME) derivatives were analyzed by capillary gas chromatography (GC), and the free fatty acid (FFA) derivatives and the oils were analyzed by capillary supercritical fluid chromatography (SFC). Further, mass spectroscopy of the TMS‐FAME derivatives was performed to check the purity of the derivatives. The results from the GC analyses of TMS‐FAME corresponded to the results found by SFC analysis of the FFA. The content of ricinoleic acid in the glycerolipids of R. communis was 87.7 wt%, and the content of dimorphecolic acid in D. pluvialis was 54.0 wt%. The methods were evaluated with respect to the cost, ease, and time needed for sample preparation and analysis.
A method for determining kernel moisture content and aflatoxin concentrations in peanuts
Authors: Dorner Joe W. , Cole Richard J.
Published: May 2007

A method was developed to determine kernel moisture content (KMC) and aflatoxin concentration in discrete peanut samples. Shelled peanuts were weighed to the nearest 0.01 g, and a water slurry was made by blending the peanuts for 2 min with 2.2 ml of water per g of peanuts. The slurry (10 g) was withdrawn and dried at 130°C for 3 h to determine KMC. Methanol was added to the remaining slurry and blended for an additional 1 min, and aflatoxins were quantitated with high‐performance liquid chromatography. Comparison of the slurry method with an official peanut moisture method showed good agreement between the two over a range of moisture levels. Recovery of aflatoxin B1 from spiked samples averaged 97% with an average coefficient of variation of 3.6%. The method enables determination of both KMC and aflatoxin content in peanut samples without degradation of aflatoxin that would occur when using the official moisture method.
Diffuse reflectance fourier transform infrared spectroscopy of triacylglycerol and oleic acid adsorption on synthetic magnesium silicate
Authors: Yates R. A. , Caldwell J. D. , Perkins E. G.
Published: May 2007

Diffuse reflectance fourier transform infrared (FTIR) was used to observe adsorption complexes of triacylglycerol and oleic acid on silica gel and synthetic magnesium silicate. The spectra provide evidence of the nature of the surface interaction. Triacylglycerol was shown to be physically adsorbed to both adsorbents. Oleic acid was physically adsorbed to the silica gel, but both physically and chemically adsorbed to the magnesium silicate. The FTIR spectrum of magnesium silicate that was used to treat a degraded frying oil was similar to that of oleic acid adsorbed on magnesium silicate.
Identification and function of antioxidants from oat groats and hulls
Authors: Xing Youmin , White Pamela J.
Published: May 2007

Antioxidant components of methanolic extracts of groats and hulls from Ogle oats were identified and quantified by using gas chromatography‐mass spectrometry (GC‐MS) and gas chromatography after N,O‐bis(trimethylsilyl)acetamide derivatization. Ferulic, p‐coumaric, vanillic, p‐hydroxybenzoic, 4‐hydroxyphenylacetic acids and vanillin and catechol were quantified in groat and hull extracts. Additionally, caffeic acid in groat extracts, and o‐coumaric, sinapic and slaicylic acids in hull extracts were quantified. Extracts from groats and hulls at levels of 0.05, 0.1, 0.2, and 0.3% w/w, based on total phenolic content, were added to soybean oil, and their antioxidant effectiveness was compared with that of 0.02% w/w tertiary butylhydroquinone (TBHQ) and a control (no additives) at 60°C in the dark by measuring peroxide values. Antioxidant activities of both extract sources increased with increased concentration. During 20 d of storage, the groat extract (0.3%) was not significantly different from TBHQ after day 16, and hull extracts (0.2 and 0.3%) were not significantly different from TBHQ on day 20. Oils containing pure phenolics at the same concentrations measured in the groat and hull extracts oxidized more quickly than did oils containing the extracts.
Determination of environmentally relevant physical‐chemical properties of some fatty acid esters
Authors: Krop Hildo B. , Velzen Martin J. M. v. , Parsons John R. , Govers Harrie A. J.
Published: May 2007

Fat models frequently use input parameters that are defined at environmental conditions. In a recently developed gas‐liquid chromatography method (GC‐VAP), vapor pressures, heats of vaporization, and heat capacity differences (gas‐liquid) of fatty acid esters are determined over a large temperature range that includes environmental temperatures. This method also allows an accurate determination of the normal boiling point temperature of a substance. Literature values of vapor pressure, boiling point temperature, and heat of vaporization at 298.15 K for the chosen esters are all in excellent agreement with those determined with the developed method. Correlations between carbon number and heat of vaporization are high.
Stability of furanoid fatty acids in soybean oil
Authors: Guth Helmut , Grosch Werner
Published: May 2007

Analysis of the positional distribution of the furanoid fatty acids, 10,13‐epoxy‐11,12‐dimethyloctadeca‐10, 12‐dienoic acid (F20) and 12,15‐epoxy‐13,14‐dimethyleicosa‐12,14‐dienoic acid (F22), in soybean oil (SBO) indicated that they were preferentially esterified with the primary‐OH groups of glycerol molecules. Hydrogenation of SBO reduced the concentrations of F20 and F22 somewhat. During exposure of SBO to daylight, F20 and F22 were completely degraded within two days, whereas linoleic acid and linolenic acid were not affected. β‐Carotene inhibited both the degradation of the furanoid fatty acids and their oxidation to the odorant 3‐methyl‐nonane‐2,4‐dione (MND), which contributes strongly to the light‐induced off‐flavor of SBO. A model experiment indicated that two days of light exposure of SBO, followed by filtration through silica gel and further refining, prevented the formation of MND during subsequent storage of the oil.
Comparison of rancimat evaluation modes to assess oxidative stability of fish oils
Authors: Méndez Eduardo , Sanhueza Julio , Speisky Hernán , Valenzuela Alfonso
Published: May 2007

Two Rancimat evaluation modes, the induction period (IP), and the time needed to achieve a selected difference in conductivity (tΔK) were compared for assessing relative stability of anchovy, sardine, and hake liver oils. Mean coefficients of variation were 2.5 and 2.4% for IP and tΔK values, respectively, for oils oxidized in the range 55–90°C. Natural logarithms of IP and tΔK values varied linearly with temperature (P<0.001). A linear relationship (r=0.999) was established between the IP and tΔK values (P<0.001). Relative oxidative stability of fish oils was determined with the same degree of confidence by either IP or tΔK values.
Isothermal crystallization of tripalmitin in sesame oil
Authors: Dibildox‐Alvarado Elena , Toro‐Vazquez Jorge F.
Published: May 2007

Crystallization of tripalmitin (TP) in sesame oil was investigated under isothermal conditions at a cooling rate similar to the one achieved in industrial crystallizers (1 K/min). The results obtained indicated that, at TP concentrations <0.98%, triacylglycerides of sesame oil developed mixed crystals with TP. However, at concentrations within the interval of 0.98 to 3.44%, tripalmitin crystallized independently from sesame oil. Within this concentration interval, discontinuities were observed in the behavior of the induction time of TP crystallization (Ti) in sesame oil as evidenced by differential scanning calorimetry, polarized microscopy studies, and determination of the Avrami index (n). In general, the discontinuities in Ti were associated with different polymorph states developed by TP in sesame oil as a function of its concentration and crystallization temperature. Thus, TP crystals obtained at temperatures above 296 K with 1.80 and 2.62% TP solutions had n values close to 3 and developed lamellar‐shaped crystals that are characteristic of β tripalmitin. In contrast, the crystals obtained at temperatures of 296 K and below with 1.80% and 2.62% TP solutions provided n values close to 3. Axialite‐shaped β′ TP crystals were obtained under these conditions. For the 0.98% TP solution, simultaneous production of α and β′ crystals occurred below 291 K. However, at temperatures above 291 K, a crystallization process with n=3 was obtained, and it developed a different polymorph state, i.e., β, with lamellar‐shaped TP crystals.
Synthesis of phosphatidylglycerol from soybean lecithin with immobilized phospholipase D
Authors: Wang XingGuo , Qiu AiYong , Tao WenYi , Shen PeiYing
Published: May 2007

Phosphatidylglycerol (PG) was synthesized from soybean lecithin with the help of phospholipase D (PLD) that was immobilized with calcium alginate gel‐enveloped polyethyleneimine‐glutarald ehyde. The immobilization conditions were optimized with response surface analysis: Ca‐alginate 1.39%, polyethyleneimine 7.78%, glutaraldehyde 1.22%. The conversion of phosphatidylglycerol was 87%. The properties of the immobilized PLD were: optimal temperature 25–30°C, optimal pH 8.2, ratio of ether phase and water phase 1.5–2.5:1 (vol/vol), repeated 15 batches operating with stabilizing conversion percentage of phosphatidylglycerol.
Alteration of steryl ester content and positional distribution of fatty acids in triacylglycerols by chemical and enzymatic interesterification of plant oils
Authors: Ferrari R. Ap. , Esteves W. , Mukherjee K. D.
Published: May 2007

Steryl ester content of refined and interesterified corn, soybean, and rapeseed oils has been measured via clean‐up on a short silica gel column, followed by high performance liquid chromatography with evaporative light‐scattering mass detector. Chemical interesterification, catalyzed by sodium methoxide, led to random positional distribution of fatty acids in triacylglycerols and some increase in the steryl ester content of all three oils. Enzymatic interesterification, catalyzed by the immobilized lipase from Rhizomucor miehei (Lipozyme), resulted in a distinct reduction in steryl ester content, but essentially no alteration in positional distribution of fatty acids in triacylglycerols occurred. Formation of steryl esters during chemical and enzymatic interesterification was also examined by radioactive tracer technique with [4‐14C]β‐sitosterol added as marker to refined rapeseed oil and measurement of the radioactive steryl esters formed. Chemical interesterification of rapeseed oil resulted in moderate formation (10% of total radioactivity) of radioactive β‐sitosteryl esters. Enzymatic interesterification of the oil, catalyzed by Lipozyme, led to little formation of radioactive β‐sitosteryl esters, whereas with the lipase from Candida cylindracea high proportions (>90% of total radioactivity) of 14C‐labeled β‐sitosteryl esters were formed.
Lipase‐catalyzed glycerolysis of soybean oil in supercritical carbon dioxide
Authors: Jackson Michael A. , King Jerry W.
Published: May 2007

The transesterification of soybean oil with glycerol, 1,2‐propanediol, and methanol by an immobilized lipase in flowing supercritical carbon dioxide for the synthesis of monoglycerides is described. A lipase from Candida antarctica was used to catalyze the reaction of soybean oil with glycerol, 1,2‐propanediol, ethylene glycol, and methanol. Reactions were performed in supercritical carbon dioxide at a density of 0.72 g/L and at a flow rate of 6 µL/min (expanded gas). The substrates were added at flows ranging from 2.5 to 100 µL/min. Monoglycerides were obtained at up to 87 wt%, and fatty acid methyl esters at nearly 100 wt%. The reactivity of the alcohols paralleled the solubility of the substrate in liquid carbon dioxide. Glycerol has the slowest reaction rate, only 2% of that of methanol.
Immobilization of lipases on porous polypropylene: Reduction in esterification efficiency at low loading
Authors: Bosley John A. , Peilow Alan D.
Published: May 2007

Rhizomucor miehei, Humicola sp., Rhizopus niveus, and Candida antarctica B lipases were immobilized by physical adsorption onto a macroporous polypropylene support. In an esterification reaction, the enzyme efficiency, and therefore cost‐effectiveness, is greatly affected by enzyme loading, with an apparent suppression of efficiency at low lipase loadings for both R. miehei and Humicola sp. lipases. This results in the appearance of a pronounced maximum in the efficiency‐loading relationship at approximately 100,000 lipase units (LU)/g for R. miehei lipase (10% of its saturation loading) and at approximately 200,000 LU/g for Humicola sp. lipase (50% of its saturation loading). The other lipases studied do not show similar trends. At low loadings, only a small portion of the surface area is occupied and gives the lipase the opportunity to spread; it is hypothesized that the reduction in efficiency at low loadings is due to a distortion of the active molecular conformation caused by the lipase maximizing its contact with the support as a result of its high affinityfor the support surface. The relationship between efficiency and loading was different for each of the lipases studied, which may reflect both differences in the strength of the affinity of the lipase for the support and in the ease at which the molecular conformation of the lipase can be distorted.
Alcoholysis of palm oil mid‐fraction by lipase from Rhizopus rhizopodiformis
Authors: Basri M. , Heng A. C. , Razak C. N. A. , Wan Yunus W. M. Z. , Ahmad M. , Rahman R. N. A. , Ampon K. , Salleh A. B.
Published: May 2007

A mycelial lipase from Rhizopus rhizopodiformis was prepared in fragment form. The lipase was examined to catalyze the alcoholysis of palm oil mid‐fraction (PMF) in organic solvents. High percentage conversions of PMF to alkyl esters were achieved when methanol or propanol was used as acyl acceptor. Of the two most prevalent fatty acids in PMF, palmitic acid seemed to be preferred over oleic acid in the formation of methyl and propyl esters. The optimal ratio of oil to methanol in the alcoholysis reaction is 1 to 2 moles. The lipase exhibited high alcoholysis activities in nonpolar solvents (log P>2), such as hexane, benzene, toluene, and heptane. The enzyme showed exceptionally high thermostability.
Microwave roasting and phospholipids in soybeans (Glycine max. L.) at different moisture contents
Authors: Yoshida Hiromi , Takagi Sachiko , Kajimoto Goro , Yamaguchi Maki
Published: May 2007

The effects of microwave roasting on phospholipids in soybeans were investigated in relation to moisture. Whole soybeans at different moistures (9.6, 38.2, and 51.9%) were roasted by exposure to microwaves at a frequency of 2,450 MHz. During microwave treatments, the lower the moisture content, the higher was the internal temperature in soybeans at the end of microwave roasting. Total lipids were extracted from the beans after microwave treatment, and the phospholipids were separated with thin‐layer chromatography. Phosphatidylcholine was the principal phospholipid in the extracted lipids from all unroasted and roasted bean samples. After microwave roasting, phospholipids containing an amino group, especially phosphatidylethanolamine, decreased substantially (P<0.05) in lower‐moisture soybeans. However, increasing the moisture content depressed a rise in the internal temperature of soybeans and prevented a reduction in phospholipids and/or polyunsaturated fatty acids in the phospholipids. Based on the changes in the composition and fatty acid distribution of phospholipids in soybeans during microwave roasting, it is necessary to consider the moisture content in soybeans when roasting in a microwave oven.
Spectral confirmation of trans monounsaturated C18 fatty acid positional isomers
Authors: Mossoba M. M. , McDonald R. E. , Roach J. A. G. , Fingerhut D. D. , Yurawecz M. P. , Sehat N.
Published: May 2007

The trans octadecenoic acid methyl ester isomers were obtained from a partially hydrogenated soybean oil sample and isolated by silver‐ion high‐performance liquid chromatography. The double bond configuration was confirmed to be trans by using gas chromatography‐direct deposition‐Fourier transform infrared spectroscopy. The double bond positions for nine individual trans octadecenoic acid positional isomers were confirmed by gas chromatography‐electron ionization mass spectrometry after derivatization to 2‐alkenyl‐4,4‐dimethyloxazoline. These nine trans positional isomers were resolved on either one of the two polar 100% cyanopropylpolysiloxane 100‐m capillary columns, SP 2560 and Cp‐Sil 88, at an isothermal temperature of 140°C. These nine isomers were confirmed to have double bonds at carbons C‐8 through C‐16. The pair of trans octadecenoic acid positional isomers with double bonds at C‐13 and C‐14 are reported for the first time to be resolved by gas chromatography.
Simplified gravimetric determination of total fat in food composites after chloroform‐methanol extraction
Authors: Phillips Katherine M. , Tarragó‐Trani Maria Teresa , Grove Tina M. , Grün Ingolf , Lugogo Rita , Harris Robert F. , Stewart Kent K.
Published: May 2007

A modification of Association of Official Analytical Chemists (AOAC) method 983.23 for the quantitative determination of total lipid in food composites was evaluated for the measurement of total fat. The procedure is based on the Bligh and Dyer chloroform/methanol total lipid extraction. Relative to AOAC 983.23, the proposed method is less labor‐intensive and is applicable to batch analysis of a larger number of samples, thus reducing the cost of analysis and increasing sample throughput. Total lipid values from the proposed method are comparable to those from AOAC 983.23 and slightly higher than total fat determined by acid hydrolysis (AOAC 954.02, 945.44, or 922.06). Recoveries of standard additions of different food‐grade oils from a mixed food composite were essentially quantitative, ranging from 96 to 101%. Total lipid measured in Total Diet Standard Reference Material 1548 (SRM 1548, National Institute of Standards and Technology) was 101% of the certified mean total fat content and within the certified range. The method is to be suitable for analysis of food composites with between 0.15 and 1.5 g total fat (3 to 30% by weight). More than 600 samples of a variety of total diet composites were collected and assayed as diet quality control samples for two National Heart, Lung and Blood Institute‐sponsored multicenter clinical feeding trials: DELTA (Dietary Effects on Lipoproteins and Thrombogenic Activity) and DASH (Dietary Approaches to Stop Hypertension). The mean coefficient of variation was 1.2% for duplicate assays of these samples over the course of two years and multiple analysts. In addition, total lipid values for more than 200 samples of a diet composite quality control material, used in this laboratory over a two‐year period, had a 3.99% coefficient of variation. Although the accuracy of all gravimetric total fat methods with respect to the U.S. Food and Drug Administration’s Nutritional Labeling and Education Act (NLEA) definition of total fat as the sum of triglycerides remains to be determined, the reported modification of AOAC 983.23 yields a total fat content of acceptable accuracy relative to other gravimetric methods, and with proper quality control the method has excellent precision.
Endogenous antioxidants and stability of sesame oil as affected by processing and storage
Authors: Shahidi F. , Amarowicz R. , Abou‐Gharbia H. A. , Shehata A. Adel Y.
Published: May 2007

The effect of processing of coated and dehulled sesame seeds on the content of endogenous antioxidants, namely sesamin, sesamolin, and γ‐tocopherol in hexane‐extracted oils, was studied over 35 d of storage under Schaal oven test conditions at 65°C. Seeds examined were Egyptian coated (EC) and dehulled (ED) and Sudanese coated (SC) varieties. Processing conditions of raw (RW) seeds included roasting at 200°C for 20 min (R), steaming at 100°C for 20 min (S), roasting at 200°C for 15 min plus steaming for 7 min (RS) and microwaving at 2450 MHz for 15 min (M). The sesamin content in fresh oils from EC, ED, and SC raw seeds was 649, 610, and 580 mg/100 g oil, respectively. Corresponding values for the content of sesamolin in oils tested were 183, 168 and 349 mg/100 g oil, respectively. Meanwhile, the content of γ‐tocopherol, the only tocopherol present in the oils, ranged from 330 to 387 mg/kg sample. The effect of processing on changes in the sesamin content in oils from coated seeds was low and generally did not exceed 20% of the original values. On the other hand, oils from dehulled seeds underwent a more pronounced decrease in their sesamin content than the oil from coated seeds after 35 d of storage at 65°C. The corresponding changes in sesamolin and γ‐tocopherol contents were more drastic. The RS treatment, which would be the optimal to prepare sesame oil with better quality, was found to retain 86, 80 and 60% of the sesamin, sesamolin and γ‐tocopherol, respectively, originally present in the seeds after the storage period. The loss in the content of endogenous antioxidants present in the oils paralleled an increase in their hexanal content.
Soybean‐lecithin supplementation of practical diets for juvenile goldfish (Carassius auratus)
Authors: Lochmann Rebecca , Brown Ramone
Published: May 2007

Soybean lecithin, alone or in combination with cod liver or soybean oil, was tested as a supplemental lipid in practical diets for juvenile (0.3 g) goldfish (Carassius auratus). Goldfish were fed one of five diets containing: (i) 4% cod liver oil (CLO); (ii) 2% CLO+2% lecithin (LEC); (iii) 4% soybean oil (SBO); (iv) 2% SBO+2% LEC; (v) 4% LEC. After 6 wk, weight gain and feed efficiency of fish fed diets with 4% LEC were significantly higher than those of fish fed diets with 4% CLO or SBO. Gain and feed efficiency of fish fed diets with combinations of LEC and CLO or SBO were intermediate. Survival and whole‐body lipid were unaffected by diet. Possible mechanisms of performance enhancement in goldfish fed LEC include provision of myoinositol or phosphatidylcholine to support rapid membrane proliferation, enhanced absorption of dietary lipid, and facilitation of lipid transport.
A highly regioselective synthesis of δ‐lactones from meadowfoam fatty acids
Authors: Isbell Terry A. , Plattner Beth A.
Published: May 2007

Meadowfoam fatty acids, when treated with mineral acid catalysts in the presence of polar nonparticipating solvents, undergo a facile ring closure to form δ‐lactones. Perchloric and sulfuric acids catalyze the cyclization at concentrations of 0.6–13 mole equivalents, both neat and in the presence of solvent. Under constant acid concentrations, methylene chloride was found to increase the rate of reaction, the regioselectivity for the formation of δ‐lactone, and the overall yield. In the absence of solvent, increased acid concentration improved the yield of lactone but reduced regioselectivity for the δ‐isomer. Solvent polarity plays a significant role in the regioselectivity of the cyclization for δ‐lactone, with solvents of higher dielectric strength providing larger δ/γ ratios (38:1) and higher yields up to 92%.
Genetic regulation of linolenic acid concentration in wild soybean Glycine soja accessions
Authors: Pantalone V. R. , Rebetzke G. J. , Burton J. W. , Wilson R. F.
Published: May 2007

Soybean [Glycine max (L.) Merr.] oil from current commercial cultivars typically contains ca. 8% linolenic acid. Inheritance studies have shown that linolenic acid concentration in soybean seed is determined by at least two genes which govern activity of the predominant ω‐6 and ω‐3 desaturases. Selection of germplasm exhibiting homozygous recessive alleles that encode these desaturases has enabled development of soybeans having less than 3.0% linolenic acid. However, accessions of the wild ancestor of modern soybean cultivars, Glycine soja (Sieb. and Zucc.), have oils containing twice the highest linolenic acid concentration found in normal G. max cultivars. Although little is known about inheritance of linolenic acid in wild soybean, it would appear that additional or alternative forms of genes may govern its synthesis. To test this hypothesis, cultivated soybean germplasm was hybridized with wild soybean genotypes having significant differences in linolenic acid concentration. Seed of F3 progeny from these G. max x G. soja populations exhibited distinct segregation patterns for relative estimates of ω‐6 and ω‐3 desaturase activity. Frequency class distribution analyses of the segregation patterns, and linear relations between median ω‐6 or ω‐3 desaturation estimates and corresponding linolenic acid concentration among allelic classes from these populations suggested the high‐linolenic acid trait in wild soybean genotypes was determined by a set of desaturase alleles that were different from corresponding alleles in G. max. Introgression of these alternative alleles in G. max germplasm opens a new avenue of research on the genitic regulation of linolenic acid, and may lead to the production of highly polyunsaturated soybean oils for various industrial applications.
Positional distribution of Δ5‐acids in triacylglycerols from conifer seeds as determined by partial chemical cleavage
Authors: Blaise Pierre , Tropini Veronique , Farines Marie , Wolff Robert L.
Published: May 2007

The positional distribution of various Δ5‐acids in the seed triacylglycerols from several conifer species has been established after partial chemical degradation with Grignard reagent. The species studied were representative of four conifer families and were specially selected for their particularly high Δ5‐acid contents. These species were Taxus baccata (Taxaceae; 5,9‐18:2 acid, 11.9%), Larix decidua (Pinaceae; 5,9,12‐18:3 acid, 28.5%), Sciadopytis verticillata (Taxodiaceae; 5,11,14‐20:3 acid, 16.7%), and Juniperus communis (Cupressaceae; 5,11,14,17‐20:4 acid, 19.8%). Calculations from the fatty acid compositions of triacylglycerols and of the mixture of 1,2‐ and 2,3‐diacylglycerols generated by the Grignard reagent indicated that, for the four species, there was a considerable enrichment of Δ5‐acids (generally more than ten times) in the 1,3‐positions as compared to the 2‐position, where Δ5‐acids represented always less than 2% of total fatty acids esterified to triacylglycerols. This distribution was practically independent from the species (four families studied), the chainlength (18 or 20 carbon atoms), and the number of ethylenic bonds (two to four) in the Δ5‐acids. Similar distributions were established for triacylglycerols from the seeds of three pine species that are available on a ton‐scale: Pinus pinea, P. koraiensis, and P. pinaster. These observations confirm and extend previous studies conducted with other conifer species by similar techniques or by 13C‐nuclear magnetic resonance spectroscopy. Consequently, the almost exclusive location of Δ5‐acids in the external positions of triacylglycerols is now well established and appears to be a general feature of conifer seed oils.
The effect of partial glycerides on trilaurin crystallization
Authors: Smith Paul R. , Povey Malcolm J. W.
Published: May 2007

The effects of partial glycerides of fatty acid chainlength from C10 to C18 on trilaurin crystal growth rate were investigated. Glycerides of particular form were found to have similar effects. Free fatty acids or monoglycerides either had little effect or slightly increased growth rates, whereas diglycerides, especially 1,3‐diglycerides reduced them. If a particular glyceride has shorter chainlengths than trilaurin, the inhibition of crystallization is extremely small. For slightly longer chainlengths, a significant reduction of crystallization rate is seen, although smaller than with the addition of partial laurates. Maximum inhibition occurs with chainlength matching, and the magnitude decreases with increasing difference between host and guest chainlength.
Lipase‐catalyzed incorporation of oleic acid into melon seed oil
Authors: Moussata Charment O. , Akoh Casimir C.
Published: May 2007

The ability of lipase PS30 (Pseudomonas sp.) to modify the fatty acid profile of melon seed oil by incorporation of oleic acid (18:1n‐9) was investigated. The transesterification was carried out in hexane in an orbital shaking water bath at 55°C for 24 h with methyl oleate (70% pure) as acyl donor. Oleic acid content increased from 13.5% to 53%, and linoleic acid (18:2n‐6) content decreased from 65% to 33%. The incorporation of oleic acid into melon seed oil by Pseudomonas sp. lipase helped balance the fatty acid profile of the oil in terms of monounsaturated (18:1n‐9) and essential fatty acids (18:2n‐6).
Photoautotrophic cultivation of the green alga Chlamydomonas reinhardtii as a method for carbon dioxide fixation and α‐linolenic acid production
Authors: Akimoto Masamichi , Yamada Hidenao , Ohtaguchi Kazuhisa , Koide Kozo
Published: May 2007

Focusing on CO2 fixation and α‐linolenic acid (ALA) production, photoautotrophic cultivation of the green alga Chlamydomonas reinhardtii was investigated by using a culture medium of pH 6.8 under a 5 vol% CO2‐enriched atmosphere. The optimum cultivation temperature and light intensity for growth were 25°C and 12 klux, respectively. The cellular ALA content nearly doubled to 11.9 mg/g of dry cells when the concentration of culture medium was doubled. Simulation of chemostat cultivation showed that the rate of CO2 fixation and ALA productivity per unit volume of culture medium could reach 1.01 kg CO2/(m3 · d) and 7.46 g ALA/(m3 · d), respectively, at a cell concentration of 0.57 kg cells/m3.
Peroxisomal changes during hiberation of jerboa (Jaculus orientalis)
Authors: Kabine M. , Cherkaoui‐Malki M , Clémencet C. ‐C. , El Kebbaj M. S. , Latruffe N.
Published: May 2007

As a member of the order of Rodentia, jerboa (Jaculus orientalis) is a natural deep hibernator and lives in subdesert highland in many parts of the world, including Morocco. Its small size (adult body weight ∼100 g), availability in the wild, tolerance to laboratory conditions, and some unique peroxisomal properties make it a suitable research subject for exploring peroxisome biogenesis under prehibernating and hibernating states. During 3 w, animals referred to as the prehibernator group were exposed to cold temperature (5 to 7°C) with food ad libitum. Part of the prehibernator group entered deep hibernation 24 to 48 h after starvation. Animals were sacrificed 4 and 6 d after starting hibernation. As a control, a third group, consisting of active animals, was maintained at 22°C. Concerning hibernation, results from plasma analysis showed an increased level for both ketonemia and ureamia, while triglyceredemia was decreased. Liver acyl‐CoA oxidase activity, a peroxisomal b‐oxidation enzyme, increased during hibernation. Liver peroxisomal urate oxidase was induced only during the prehibernating state and remained at an increased level until the fourth day of hibernation. The variations were concomitant to a decrease in peroxisomal protein yield and a differential change in peroxisomal protein pattern in sodium dodecyl sulfate‐polyacrylamide gel electrophoresis during prehibernating or hibernating states. These preliminary results show that cold exposure and hibernation affect biogenesis of liver peroxisomes in jerboa.
Analysis of sn‐1(3)‐ and sn‐2‐short‐chain acyl isomers of triacylglycerols in butteroil by gas‐liquid chromatography
Authors: Kemppinen Asmo , Kalo Paavo
Published: May 2007

The aim of the study was to determine major triacylglycerols (TG), and sn‐1(3) and sn‐2 isomers of butyryl and caproyl TG in butteroil (BO) and interesterified butteroil (IBO) by gas‐liquid chromatography (GLC) and silver ion column chromatography. Altogether, 112 molecular species of TG were synthesized by interesterification and their retention indices were determined. Molar empirical correction factors for TG were determined using linear calibration. Retention indices showed that sn‐1(3) and sn‐2 isomers of the TG containing one short‐chain acyl (butyrate, caproate) and two long‐chain acyls (lauroate, myristate, palmitate, stearate, and oleate) were separated on a phenyl (65%) methylsilicone column. The difference between retention indices of 1(3)‐ and 2‐short‐chain acyl isomers ranged from 14 to 19, and from 9 to 16 for butyrates and caproates, respectively. The proportion of sn‐2 isomers of butyrates averaged 1.4%, but only traces of sn‐2 isomers of caproates were detected in butteroil. The ratio of sn‐1(3)‐ to sn‐2‐butyrates and caproates in interesterified butteroil averaged 2.0:1. The most abundant molecular species of mono‐short‐chain TG in butteroil were BPP + BMS (5.6 mol%), BPO + BSPo (4.8 mol%), BMP + BLaS (3.4 mol%), BMO + BPPo (2.7 mol%), BPS (2.5 mol%), and CoPP + CoMS (2.3 mol%).
Gas chromatography‐fourier transform infrared spectrometry of fatty acids: New applications with a direct deposition interface
Authors: Sémon E. , Ferary S. , Auger J. , Le Quéré J. L.
Published: May 2007

Infrared spectroscopy is a suitable spectroscopic method to differentiate geometric Z and E isomers of unsaturated compounds. A direct‐deposition Fourier transform infrared spectrometer (FTIR), coupled to a gas chromatograph, was used successfully to analyze with a high sensitivity traces of C18:1 fatty acid methyl ester (FAME) isomers. It could also conclusively distinguish between isomers of conjugated diunsaturated FAME. The achievable sensitivity of this direct‐deposition device makes possible accurate FAME mixture analyses that are not currently attainable with the more conventional light‐pipe interface.
Determination of sterols, oxysterols, and fatty acids of phospholipids in cells and lipoproteins: A one‐sample method
Authors: Blache D. , Durand P. , Girodon F. , Gesquière L. , Loreau N.
Published: May 2007

In addition to fatty acids, especially polyunsaturated species, cholesterol oxidizes and leads to various oxygenated derivatives, named oxysterols. They display a wide range of adverse biological properties. Monitoring oxysterols is important in the evaluation of the potential risks associated with lipid oxidation. In the present study, a quick and reliable method was developed for analysis of oxysterols, sterols, and fatty acid composition of phospholipids in the same biological sample. Total lipid extraction was determined after addition of several internal standards (epicoprostanol for sterols, 19‐hydroxy‐cholesterol for oxysterol and di‐heptadecanoyl‐phosphatidylcholine for phospholipid fatty acids). Cold acetone‐mediated precipitation was then used to fractionate sterols from phospholipids. The phospholipid‐containing precipitate was transmethylated for fatty acid analysis by gas chromatography. The sterol‐ and oxysterol‐containing phase was saponified under mild conditions to avoid artificial oxysterol generation and was analyzed by gas chromatography after derivatization into trimethylsilyl ethers. The overall procedure was found to be specific with good recovery and reproducibility for sterols, oxysterols [mean coefficient of variation in percent (CV), 11.3%] as well as phospholipid fatty acids (CV, 5.6%). This procedure has been used to document in vitro free radical treated‐human low‐density lipoproteins and erythrocytes. Results demonstrated that this method is a useful tool in assessing qualitative and quantitative differences in oxysterols and phospholipid fatty acid patterns attributed to lipid oxidation.
Determination of low trans levels in refined oils by fourier transform infrared spectroscopy
Authors: De Greyt W. , Kint A. , Kellens M. , Huyghebaert A.
Published: May 2007

A Nicolet 410 Fourier (FTIR) spectrophotometer, equipped with a DGTS detector and a sample cell with NaCl windows (nominal pathlength=50 μm), was used for the development of an FTIR method for routine analysis of low trans levels in physically refined oils. The approach of the study differed from those previously described in that a separate calibration curve was established for each type of oil. Quantitation was established by use of Basic Quant Software® and by measuring the peak height at 967 cm−1 relative to a baseline drawn between 1002 and 932 cm−1. The slope of the different calibration curves established in six vegetable oils (soybean, corn, sunflower, high‐oleic sunflower, low‐erucic rapeseed, and high‐erucic rapeseed) was close to 1 (0.9942–1.0041), and correlation coefficients (r2) were rather good (0.9990–0.9999). FTIR spectra of 20 soybean oil samples were collected and quantitated with the different calibrations. Compared to previous reported literature data, increased accuracy (mean difference=0.05%; standard deviation of difference=0.11%) and reproducibility (r2=0.09–0.12%) were obtained when the FTIR spectra were quantitated with a calibration curve based on 10 physically refined soybean oil samples.
Applications of chromatographic techniques to evaluate enzymatic hydrolysis of oxidized and polymeric triglycerides by pancreatic lipase in vitro
Authors: Márquez‐Ruiz G. , Guevel G. , Dobarganes M. C.
Published: May 2007

With the aim of studying the susceptibility to enzymatic hydrolysis of oxidized and polymeric triglycerides (TG) that are formed during frying, various chromatographic techniques were applied in combination, i.e., adsorption chromatography, high‐performance size‐exclusion chromatography (HPSEC), and thin‐layer chromatography‐flame ionization detection (TLC‐FID). Polar fractions, isolated by adsorption chromatography from thermoxidized trilinolein as model system, and real used frying fats and oils, were analyzed by HPSEC before and after incubation with pancreatic lipase in vitro. Also, the influence of degradation level of used frying oils on hydrolysis of intact TG was investigated with the additional aid of TLC‐FID. Results showed the high hydrolysis rate of oxidized TG monomers in contrast to the significant discrimination of pancreatic lipase against TG dimers and, particularly, TG polymers. On the other hand, hydrolysis of intact TG can be affected by the presence of dimers and polymers in abused frying oils.
Application of headspace analysis to the study of aroma compounds‐lipids interactions
Authors: Druaux C. , Le Thanh M. , Seuvre A. ‐M. , Voilley A.
Published: May 2007

Taking into account interactions between aroma compounds and food components is necessary to better manage the flavoring of food products. These interactions occur at a molecular level and reflect changes, at a macroscopic level, in thermodynamic equilibria, such as solubility or volatility. The rate of transfer of an aroma compound from the liquid to the vapor phase can be affected as well. The behavior of aroma compounds in water and lipid solutions was studied in two complementary ways, a thermodynamic and a kinetic approach (head‐space analysis). The transfer rate of volatiles at the liquid‐water interface does not only depend on the hydrophobicity of the aroma compounds. Vapor‐liquid partition and activity coefficients show the presence of solute‐solvent interactions. The Gibbs free energy values indicate their physicochemical nature.
Interference of 7‐dehydrocholesterol in α‐tocopherol determination by high‐performance liquid chromatography: A possible screening test for the smith‐lemli‐opitz syndrome
Authors: Michel F. , Cristol J. P. , Vernet M. H. , Feillet C. , Carbonneau M. ‐A. , Léger C. L. , Castel J. , Descomps B.
Published: May 2007

7‐Dehydrocholesterol (7‐DHC), a normal cholesterol precursor, accumulates in plasma and tissues of patients affected by the Smith‐Lemli‐Opitz (SLO) syndrome, a recessive autosomic disease characterized by mental retardation and physical malformations. In these patients, we suspected that 7‐DHC interfered with α‐tocopherol (α‐T) determination because this steroid could be coeluted with α‐tocopherol acetate (α‐TA), an internal standard commonly used for α‐T determination, and because the conjugated dienic structure of 7‐DHC strongly absorbs at 292 nm. The aim of this work was (i) to characterize the interfering material and (ii) to evaluate the possibility of a rapid screening test for SLO syndrome identification from 7‐DHC determination by reverse‐phase chromatography high‐performance liquid chromatography (HPLC). Human plasmas (control and SLO syndrome) were extracted with hexane after ethanol protein precipitation and addition of ascorbic acid as protective agent plus α‐TA or δ‐tocopherol (δ‐T) as internal standards. The dry hexane extract was used for HPLC, and trimethylsilyl ethers derivatives of the extracts were submitted to gas chromatography (GC) and gas chromatography‐mass spectrometry (GC‐MS). The material interfering in the α‐T determination was unambiguously identified to 7‐DHC by retention time (RT) relative to standard, RT relative to δ‐T, and analysis of the eluted material by GC and by GC‐MS. In α‐T determination, the interference can be eliminated by using δ‐T as internal standard instead of α‐TA. Rapid detection and evaluation of 7‐DHC in plasma appear to be possible by HPLC under the conditions described; comparison with the GC reference method suggests that the rapid HPLC determination of 7‐DHC in plasma can be used within the 1–40 mg/dL range, values commonly found in SLO syndrome.
Identification of conjugated fatty acids by gas chromatography‐mass spectrometry of 4‐methyl‐1,2,4‐triazoline‐3,5‐dione adducts
Authors: Dobson Gary
Published: May 2007

4‐Methyl‐1,2,4‐triazoline‐3,5‐dione was reacted with conjugated fatty acid methyl esters to form Diels‐Alder cycloaddition products. The electron impact mass spectra of conjugated octadecadienoates and 9,11,13‐octadecatrienoate were simple and informative and allowed the positions of the double bonds to be determined. The dienes gave single adducts whereas the triene formed four products that corresponded to two stereoisomers of the adducts of the 9,11‐diene system and two of the 11,13‐diene system. The method can be used to complement other methods for identifying conjugated fatty acids.
Oxidation in fish lipids during thermal stress as studied by 13C nuclear magnetic resonance spectroscopy
Authors: Medina Isabel , Sacchi Raffaele , Giudicianni Italo , Aubourg Santiago
Published: May 2007

13C Nuclear magnetic resonance spectroscopy has been applied to elucidate the mechanism of lipid oxidation occurring during thermal treatment of fish. Effects of temperature and time of processing have been studied by means of a model system of lipids, extracted from salmon (Salmo salar) muscle, to simulate industrial conditions of canning. Unsaturated fatty acids located at the sn‐2 position of the glycerol moiety were the most prone to oxidative damage. Regarding the mechanism of the reaction, results inferred from olefinic and methylenic resonances indicated a higher susceptibility of the allylic sites closest to the carbonyl group, followed by those placed near the methyl terminal group. Unsaturations located in the middle of the carbon chain did not show much damage. The glyceryl region provided an unusual resonance at 53.4 ppm, which could be assigned to a hydroxylic compound formed during process.
The presence of oxidizing enzyme activities in virgin olive oil
Authors: Georgalaki M. D. , Sotiroudis T. G. , Xenakis A.
Published: May 2007

Samples of Greek virgin olive oils were examined for the presence of proteins and oxidative enzyme activities. All oil samples tested contained detectable amounts of protein, as well as lipoxygenase and polyphenol oxidase activities. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and size‐exclusion chromatography of olive oil extracts revealed the presence of low‐molecular‐mass (10–40 kDa) silver‐staining and ultraviolet‐absorbing components, respectively. Both lipoxygenase and polyphenol oxidase catalytic activities were heat‐ and protease‐sensitive, and they expressed Michaelis‐Menten kinetics.