bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidant activity of minor amounts of γ‐tocopherol in natural triacylglycerols
Authors: Lampi Anna‐Maija , Hopia Anu , Piironen Vieno
Published: May 2007

The effects of minor amounts of γ‐tocopherol on the oxidation of natural triacylglycerols (TAG) of rapeseed (RO) and butter oils (BO) were studied. Four different TAG materials were blended from chromatographically purified TAG that contained 100–25% of RO TAG. The RO TAG contained from <1 to 43 µg γ‐tocopherol per gram of TAG, which corresponded to ≤6% of the total tocopherols in the original RO. The TAG were held at 40°C in the dark for 4 wk and followed at regular intervals by measurements of hydroperoxide formation by peroxide values and of secondary product formation by p‐anisidine values at regular intervals. In all TAG, minor amounts of γ‐tocopherol retarded oxidation. In RO TAG, concentrations as low as 11 µg/g of γ‐tocopherol (1.5% of the total tocopherols in the original RO) were enough to decrease hydroperoxide and secondary product formation to 46 and 39%, respectively. The effect was even more important in TAG mixtures that contained BO TAG. There were no significant differences between oxidation of the RO TAG at 24 µg/g, the 75% RO TAG mixture at 11 µg/g, and the 50% RO TAG mixture at 3 µg/g of γ‐tocopherol. Even at these minor levels, γ‐tocopherol was a significant antioxidant, which is important in oxidation studies of purified model systems.
Optimization of arachidonic acid production by Mortierella alpina Wuji‐H4 isolate
Authors: Chen H. C. , Chang C. C. , Chen C. X.
Published: May 2007

A fungal isolate Wuji‐H4 with a dense‐lobe rosette growth pattern on malt extract agar was identified as Mortierella alpina Peyronel. It was capable of producing 504 mg/L of arachidonic acid (AA) in the screening medium. Its AA content accounted for 42.4% of the total fatty acids. The AA yield was raised to 1,817 mg/L by a step‐by‐step approach, which uncovered that the preferred carbon source, nitrogen source, and temperature for fungal growth and lipid production were soluble starch, urea, and 24°C, respectively. Productivity was further optimized by exploiting the interactions between the constituents of the medium by the response surface method. A partial factorial design, followed by steepest ascent analysis, was carried out to locate the general vicinity of the optimal level of each nutrient. The response surface of AA production in this optimal region was then approximated with a full quadratic equation obtained from a three‐factor/five‐level central composite rotatable design. Maximum AA yield was predicted to occur in a medium that contained 99.7 g/L of soluble starch, 12.6 g/L of yeast extract, and 3.0 g/L of KH2PO4. Upon verification, the average experimental yield of AA (3,885 mg/L) was not significantly different from the predicted AA yield (3,940 mg/L), indicating that the response surface method had succeeded in exploiting the AA production potential of this new fungal isolate.
Analytical supercritical fluid extraction with lipase catalysis: Conversion of different lipids to methyl esters and effect of moisture
Authors: Snyder Janet M. , King Jerry W. , Jackson Michael A.
Published: May 2007

The fat content of lipid‐containing samples has been determined by extraction of the fat with supercritical carbon dioxide, followed by enzyme‐catalyzed methylation of the fat under supercritical conditions, prior to gas chromatography (GC) analysis. This study was initiated to determine the effect of moisture content on the extraction and conversion of lipids in oilseed and meat samples to their fatty acid methyl ester (FAME) derivatives. These samples were freeze‐dried or mixed with Hydromatrix and compared with untreated control samples by employing the above‐described supercritical fluid extraction‐reaction sequence. Particular attention was focused on minor constituents, such as phospholipids and cholesteryl esters, to see if they could be extracted and derivatized by the above technique. Recoveries and reaction conversions of the lipid species were determined with the aid of GC, high‐performance liquid chromatography, and supercritical fluid chromatography for analyses of the extracted lipids. Total fat values were higher from the freeze‐dried meat and oilseed samples than from samples mixed with Hydromatrix or left untreated. Extraction of cholesteryl esters was better than 90%, and conversion of the cholesteryl esters to FAME was 93% or higher. Extraction of phosphatidic acid was only 88% compared to more than 90% recoveries for the other phospholipid species. FAME conversion was better than 96% for all phospholipid samples in the study.
Enzymatic alcoholysis reaction of soy phospholipids
Authors: Ghosh M. , Bhattacharyya D. K.
Published: May 2007

Lipase‐catalyzed alcoholysis of soy phospholipids was investigated to simultaneously make lysophospholipids and fatty acid esters of individual alcohols. Alcoholysis was carried out by stirring a mixture of soy phospholipids and individual alcohols in equimolar proportions with 10% (by weight of reactants) Mucor miehei lipase at 55°C for 24 h. The products were isolated by column chromatography after removal of the lipase. Lysophospholipids (in 69–78% molar yield) were obtained from soy phospholipids, and the yield of esters of various alcohols also conformed nearly with theoretical yields.
Biotransformation of 12‐hydroxyoctadecanoic acid to 12‐hydroxyoctadecanamide by Bacillus cereus 50
Authors: Huang J K , Keudell K. C. , Klopfenstein W. E. , Wen L. , Bagby M. O. , Vesonder R. F. , Norton R. A. , Weisleder D.
Published: May 2007

A new microbial isolate (Bacillus cereus 50) transformed 12‐hydroxyoctadecanoic acid to 12‐hydroxyoctadecanamide when grown aerobically in 1% yeast extract medium at 30°C, shaken at 250 rpm for 2 to 5 d. The compound was purified by thin‐layer chromatography and characterized by infrared, gas chromatography, mass spectrometry, and nuclear magnetic resonance. The yields of 12‐hydroxyoctadecanamide were 9.1 and 21.5% after 2 and 5 d, respectively.
Lipase‐catalyzed randomization of fats and oils in flowing supercritical carbon dioxide
Authors: Jackson M. A. , King J. W. , List G. R. , Neff W. E.
Published: May 2007

Enzymes can frequently impart more selectivity to a reaction than chemical catalysts. In addition, the use of enzymes can reduce side reactions and simplify post‐reaction separation problems. In combination with an environmentally benign and safe medium, such as supercritical carbon dioxide (SC‐CO2), enzymatic catalysis makes supercritical fluids extremely attractive to the food industry. In this study, randomization of fats and oils was accomplished with an immobilized lipase in flowing SC‐CO2. Triglycerides, adsorbed onto Celite, are solubilized in CO2 and carried over 1–10 g immobilized lipase derived from Candida antarctica. The degree of randomization and rate of triglyceride throughput could be controlled by CO2 pressure and flow rate and quantity of enzyme used. The dropping points and solid fat indices of the resulting randomized oils were compared to oils that were randomized by conventional methods with sodium methoxide. Reversed‐phase high‐performance chromatography with flame‐ionization detection was used to quantitate changes in triglyceride composition of various substrates, such as palm olein and high‐stearate soybean oil. The resultant randomized oil mixtures have properties, e.g., solid fat index, that make them potential candidates for incorporation into traditional margarine formulations.
Chemoenzymatic production of (+)‐coriolic acid from trilinolein: Coupled synthesis and extraction
Authors: Gargouri Mohamed , Legoy Marie Dominique
Published: May 2007

Chemoenzymatic conversion of trilinolein to (+)‐coriolic acid was investigated in this work. Lipase‐catalyzed hydrolysis of trilinolein and lipoxygenation of liberated linoleic acid were coupled in a two‐phase medium that consisted of a pH 9 borate buffer and a water‐immiscible organic solvent (octane). High concentrations of trilinolein could be dissolved in the organic phase (up to 340 mM). Linoleic acid, liberated after hydrolysis, transferred to the aqueous phase and was enzymatically converted to the preferred 13(S)‐hydroperoxy‐9Z,11E‐octadecadienoic acid with soybean lipoxygenase‐1. This product, which remained in the aqueous phase, could be recovered by centrifugation and then chemically reduced to (+)‐coriolic acid (purity >95%). Recovery of this compound by liquid‐liquid extraction was easy. The structure of (+)‐coriolic acid has been confirmed by 1H nuclear magnetic resonance spectroscopy, mass spectrometry, and infrared spectroscopy. High yields were obtained with pure trilinolein or sunflower oil as initial substrates.
Studies on phytosterol oxides. I: Effect of storage on the content in potato chips prepared in different vegetable oils
Authors: Dutta Paresh Chandra , Appelqvist Lars‐Åke
Published: May 2007

Potato chips fried in palm oil, sunflower oil, and high‐oleic sunflower oil were studied for the content of different phytosterol oxides during 0 to 25 weeks of storage in the dark. Oxidation products of sitosterol (24α‐ethyl‐5‐cholesten‐3β‐ol) and campesterol (24α‐methyl‐t‐cholesten‐3β‐ol) were synthesized to help identify the phytosterol oxides. The oxides of phytosterols were analyzed by preparative thin‐layer chromatography, solid‐phase extraction, capillary column gas chromatography (GC), and GC‐mass spectrometry. Epimers of 7‐hydroxysitosterol and 7‐hydroxycampesterol; 7‐ketositosterol and 7‐ketocampesterol; epimers of 5,6‐epoxy‐sitosterol and 5,6‐epoxy‐campesterol; 24α‐ethylcholestane‐3β,5,6β‐triol (dihydroxysitosterol) and 24α‐methylcholestane‐3β,5,6β‐triol (dihydroxycampesterol) were detected and quantitated in the samples of chips fried in different vegetable oils. Potato chips fried in palm oil had the lowest level of total sterol oxides, ranging from 5 to ca. 9 ppm in the lipids from time 0 to 25 wk of storage. The level of total sterol oxides in chip samples fried in sunflower oil ranged from 46 to 47 ppm, and the lipids in samples fried in high‐oleic sunflower oil ranged from 35 to 58 ppm from 0 time to 25 wk of storage. During 25 wk of storage no considerable increase in sterol oxides was observed in the samples of chips fried in palm oil and sunflower oil. The chip samples fried in high‐oleic sunflower oil had slightly higher levels of sterol oxides after 10 and 25 weeks of storage. In addition to the levels of individual sterol oxides, a new method for enrichment of phytosterol oxides from the unsaponifiables and full‐scan mass spectra of various oxidation products of sitosterol and campesterol are reported in this paper.
Studies on phytosterol oxides. II: Content in some vegetable oils and in French fries prepared in these oils
Authors: Dutta Paresh Chandra
Published: May 2007

Hydrogenated rapeseed oil/palm oil blend, sunflower oil and high‐oleic sunflower oil, and French fries fried in these oils were assessed for contents of sterol oxidation products. Different oxidation products of phytosterols (7α‐ and 7β‐hydroxy‐sito‐and campesterol, 7‐ketosito‐ and 7‐ketocampesterol, 5α,6α‐epoxy‐sito‐ and campesterol, 5β,6β‐epoxy‐sito‐and campesterol, dihydroxysitosterol and dihydroxycampesterol) were identified and quantiated by gas chromatography (GC) and GC‐mass spectroscopy. Rapeseed oil/palm oil blend contained 41 ppm total sterol oxides before frying operations. After two days of frying, this level was increased to 60 ppm. Sunflower oil and high‐oleic sunflower oil had 40 and 46 ppm sterol oxides, respectively, before frying operations. After two days of frying operations, these levels increased to 57 and 56 ppm, respectively. In addition to campesterol and sitosterol oxidation products, small amounts of 7α‐ and 7β‐hydroxystigmasterol were detected in the oil samples. Total sterol oxides in the lipids of French fries fried at 200°C in rapeseed oil/palm oil blend, sunflower oil, and high‐oleic sunflower oil were 32, 37, and 54 ppm, respectively. The levels of total oxidized sterols, calculated per g sample, ranged from 2.4 to 4.0 ppm. In addition to the content of phytosterol oxides, full scan mass spectra of several oxidation products of stigmasterol are reported for the first time.
Effect of processing on flavor precursor amino acids and volatiles of sesame paste (tehina)
Authors: Shahidi F. , Aishima T. , Abou‐Gharbia H. A. , Youssef M. , Shehata A. Adel Y.
Published: May 2007

The content of flavor precursor free amino acids in dehulled sesame seeds, subjected to roasting (R), steaming (S), roasting plus steaming (RS) and microwaving (M), was determined and compared with those of the raw (RW) seeds. R, RS, and S had major effects in reducing the content of free amino acids from 2360 µg/g to 582, 795 and 884 µg/g, respectively; M had no effect on the content of free amino acids. Meanwhile, flavor volatiles of the raw and processed seeds were compared by means of a dynamic headspace analyzer/gas chromatograph‐mass spectrometer. Volatiles of RW seeds contained 85 compounds, whereas under the analytical conditions employed, seeds subjected to R, RS, S, and M had 117, 97, 93 and 87 compounds, respectively. Among volatiles identified in the RW seeds were 36 hydrocarbons, 8 aldehydes, 4 ketones, 8 alcohols, 2 acids, 2 esters, and 1 pyrazine. The only pyrazine identified in the RW seeds was 2,5‐dimethylpyrazine. Pyrazines, generally recognized as contributors to the roasted aroma of foods, were more numerous (10 in R, 6 in RS, 2 in S, and 2 in M) and prevalent (8.71% in R, 2.97% in RS, 2.04% in S, 0.53% in M, and 0.25% in RW) in the volatiles of processed sesame seeds. The chemical nature of pyrazines also depended on the process employed. Multivariant analysis indicated a highly negative correlation between the loss of free amino acids and production of volatile flavor compounds in the R and RS samples, while the M sample remained unchanged. Furthermore, both R and RS seeds contained dimethyl sulfide and dimethyl disulfide, whereas no sulfur‐containing compounds were present in other samples. Of the processed seeds, the flavors of R and RS samples were considered as acceptable, and the flavor intensity of the former was deemed stronger than that of the latter by the experimenters.
Soy hull as an adsorbent source in processing soy oil
Authors: Gnanasambandam R. , Proctor A.
Published: May 2007

Soy hull, a co‐product of the soybean industry, was evaluated as an adsorbent source for processing soy oil. Ground soy hull (<100 mesh), boiled soy hull, and soy hull carbon were each added to crude soy oil at various levels in the laboratory under commercial bleaching conditions. The free fatty acid (FFA), peroxide value (PV), pigments, and total phospholipid contents (PL) of treated samples were measured. The microstructure (scanning electron microscopy, SEM), X‐ray diffraction patterns (XRD), and Fourier transform infrared (FTIR) spectra of the soy hull adsorbents were also examined. The soy hull carbon was more efficient as an adsorbent relative to the ground or boiled soy hulls. The differences between ground and boiled soy hulls in the reduction of FFA were not significant. The effectiveness of adsorbents to reduce PV was: soy hull carbon > boiled soy hull = untreated soy hull; and for PL adsorption: soy hull carbon = ground soy hull > boiled soy hull. Boiling resulted in an open, porous structure, as evident from the SEM data, but carbonization did not affect the particle size. The XRD patterns of ground and boiled soy hulls were similar to those of powdered amorphous cellulose, but the carbon was more amorphous and had a random structure, as well as a more polar surface, as revealed by the FTIR spectra.
Statistical evaluation of biodegradation of news ink vehicles and ink formulations
Authors: Erhan S. Z. , Bagby M. O. , Nelsen T. C.
Published: May 2007

Soybean oil, commercial news ink vehicles—consisting of either soy or mineral oil and petroleum resins—and United States Department of Agriculture’s (USDA) 100% modified soy oil‐based vehicles were subjected to biodegradation. Soybean oil and each vehicle were inoculated with monocultures and a mixed culture of Aspergillus fumigatus, Penicillium citrinum, and Mucor racemosus. Fermentations were allowed to proceed for 5, 12, and 25 d. Results show that, in 25 d, soy oil was degraded the most, followed by the USDA’s ink vehicles (USDA I–III), Newspaper Association of America’s (NAA) hybrid soy oil‐based and commercial mineral oil‐based vehicles. Some differences were found in the abilities of the cultures to degrade the different inks. Color did not appear to affect the degradation rate in soy oil, the USDA inks, or the NAA ink but was a factor in the commercial ink.
Pseudohalogenation of methyl 9‐hydroxy‐cis‐12‐and 12‐hydroxy‐cis‐9‐octadecenoate
Authors: Naqvi Fehmida , Rauf Abdul , Siddiqui M. M. , Ahmad M. S. , Osman S. M.
Published: May 2007

Pseudohalogenation of methyl 9‐hydroxy‐cis‐12‐octadecenoate (I) and methyl 12‐hydroxy‐cis‐9‐octadecenoate (II) has been carried out with N,N‐dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, respectively. The interesting feature of these reactions was the formation of 1,4‐epoxy compounds. The structures of individual compounds were established with the help of elemental and spectral analysis.
Lipid composition and oxidative stability of oils in hazelnuts (Corylus avellana L.) grown in New Zealand
Authors: Savage G. P. , McNeil D. L. , Dutta P. C.
Published: May 2007

Hazelnut (Corylus avellana L.) samples were collected from six different cultivars of trees grown in an experimental orchard at Lincoln University. Three U.S. commercial cultivars (Butler, Ennis, and Barcelona), two European commerical cultivars (Tonda di Giffoni and Campanica), and one New Zealand selection (Whiteheart) were evaluated. The total oil, stability to oxidation of the oil, and fatty acid, tocopherol, and sterol composition were determined on samples of freshly extracted hazelnut oil. The total oil content of the seeds ranged from 54.6 to 63.2% while the stability of the oil, as measured by the Rancimat test ranged from 15.6 to 25.3 h. The content of the monounsaturated oleic acid in the oils ranged from 73.8 to 80.1% of the total fatty acids, while the tocopherol content ranged from 225.8 to 552.0 mg/g freshly extracted oil. The major desmethylsterols were sitosterol, ranging from 1416 to 1693 µg/g, campesterol, ranging from 78 to 114 µg/g, and Δ5‐avenasterol, ranging from 110 to 170 µg/g. The oil extracted from the cultivar Whiteheart was more stable (measured by Rancimat) than the oil from all other cultivars grown at the same location and under the same conditions. Whiteheart contained higher levels of total and γ‐tocopherol when compared to the other cultivars. The higher levels of tocopherol in Whiteheart help to explain the greater stability of the oil during the oxidative stress test. These results suggest that nuts from the cultivar Whiteheart could be stored longer than the other nuts tested.
Content of trans‐fatty acids in edible margarines
Authors: Tsanev R. , Russeva A. , Rizov T. , Dontcheva Iv.
Published: May 2007

Fatty acid composition, including trans‐isomers, was determined for four types of imported margarines consumed by the Bulgarian population. The results were compared with data obtained from a Bulgarian edible margarine produced under German license. Fatty acid composition and trans‐isomer content were determined by gas chromatography of fatty acid methyl esters on a packed and capillary column, respectively. The total contents of trans‐isomers of oleic and linoleic acid were within the ranges of 1.9–8.0% and 0.4–1.4%, respectively. The Bulgarian margarine contained similar quantities of trans‐isomers.
Influence of moderate amounts of trans fatty acids on the formation of polyunsaturated fatty acids
Authors: Bysted Anette , Hølmer Gunhild , Lund Pia
Published: May 2007

The effect of trans fatty acids from partially hydrogenated soybean oil and butterfat on the formation of polyunsaturated fatty acids was investigated. Five groups of rats were fed diets that contained 20 wt% fat. The content of linoleic acid was adjusted to 10 wt% of the dietary fats in all diets, whereas the amount of trans fatty acids from partially hydrogenated soybean oil (PHSBO) was varied from 4.5 to 15 wt% in three of the five diets. The fourth group received trans fatty acids from butterfat (BF), while the control group was fed palm oil without trans fatty acids. Trans fatty acids in the diet were portionally reflected in rat liver and heart phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylinositol, and phosphatidylserine. Incorporation in the sn‐1 position was compensated by a decrease in saturated fatty acids. Trans fatty acids were not detected in diphosphatidylglycerol. Compared to the presence in the dietary fats, 8t‐ and 10t‐18:1 were discriminated against in the incorporation in PE and PC from liver and heart, whereas 9t‐ and 12t‐18:1 were preferred. The formation of 20:4n‐6 was not influenced by 4.5 wt% trans fatty acids (from PHSBO) but apparently was by 10 wt% in liver. In contrast, even a content of 2.5 wt% trans fatty acids from BF reduced the formation of 20:4n‐6. The inhibitory effect of trans isomers on linoleic acid conversion was reflected less in heart than in liver and less for PE than for PC. Groups with trans fatty acids showed increased 22:6n‐3 and 22:5n‐3 deposition in liver and heart PE and PC.
Effects of steeping conditions during wet‐milling on the retentions of tocopherols and tocotrienols in corn
Authors: Wang Chunyang , Ning Jing , Krishnan Padmanaban G. , Matthees Duane P.
Published: May 2007

Vitamin E is a natural antioxidant that plays significant roles in food preservation and disease prevention. There are eight naturally occurring vitamin E isomers (tocols): α‐, β‐, γ‐, and δ‐tocopherols and α‐, β‐, γ‐, and δ‐tocotrienols. Corn oil is a major source of vitamin E. Most of the corn oil produced in the United States is a co‐product of corn wet‐milling. There is limited knowledge about the effects of corn wet‐milling on the retention of these vitamin E isomers. A high‐performance liquid chromatography method was developed for simultaneous determinations of tocols in steeped corn samples. Effects of steeping conditions (steeping time and SO2 concentration) on retention of tocols in corn were investigated. α‐Tocopherol, γ‐tocopherol, α‐tocotrienol, and γ‐tocotrienol are the predominant vitamin E isomers in the corn variety used in the study. Steeping conditions had little effect on the concentration of α‐tocopherol and α‐tocotrienol. However, a higher concentration of SO2 and a shorter steeping time gave a slightly higher γ‐tocotrienol content and lower γ‐tocopherol content. Corn kernels steeped in a vitamin C solution had a much higher concentration of the tocols than those steeped in SO2 solution.
Synthesis of polyfunctional glycerol esters: Lipase‐Catalyzed esterification of glycerol with diesters
Authors: Villeneuve P. , Foglia T. A. , Mangos T. J. , NuɁez A.
Published: May 2007

The enzymatic esterification of glycerol with dicarboxylic acids or esters was studied to produce mono‐ and/or diesterified glycerol adducts. Such materials are useful synthons in the synthesis of biodegradable polymers and surfactants. In this work two strategies were studied for preparing these prepolymeric glycerol derivatives: the lipase‐catalyzed esterification of free glycerol with diacids or esters and the reaction of supported or protected glycerol with diesters. For example, reaction of isopropylidene glycerol with dimethyl sebacate gave a >95% yield of isopropylidene glycerol‐monomethyl sebacate ester. Reaction of glycerol supported on silica with dimethyl adipate gave a 40% yield of glycerol‐monomethyl adipate ester. Best yields of glycerol‐mono‐ and diesters (70% and 10%, respectively) were obtained by direct esterification of free glycerol with a diester in a solvent‐free system containing small amounts of water (<4%).
Production of specific‐structured lipids by enzymatic interesterification in a pilot continuous enzyme bed reactor
Authors: Xu X. , Balchen S. , Høy C. E. , Adler‐Nissen J.
Published: May 2007

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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