bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence of 3‐oxo triterpenes in the unsaponifiable matter of some vegetable fats
Authors: Kolhe J. N. , Bhaskar Anil , Bringi N. V.
Published: November 2006

Fourteen vegetable oils were examined and 3‐oxo triterpenes are present in the unsaponifiable matter of shea (Butyrospermum parkii), illipe (Shorea stenoptera), mango kernel (Mangifera indica), kokum (Garcinia indica) and phulwara (Madhuca butyracea) fats but not in cocoa butter, dhupa fat (Vateria indica), soybean, peanut, mustard, corn, palm, coconut or mowrah (Madhuca latifolia) fats.Lipids.
Aspects of sterol metabolism in the yeastSaccharomyces cerevisiae and inPhytophthora
Authors: Parks L. W. , McLean‐Bowen C. , Bottema C. K. , Taylor F. R. , Gonzales R. , Jensen B. W. , Ramp J. R.
Published: November 2006

Using 5 wild‐type strains of yeast, nonequivalence in the isolation of sterol mutants was observed. Experiments are described on the effects of sterol modifications on growth, physical and enzymic properties ofSaccharomyces cerevisiae andPhytophthora cactorum. Although discontinuities in Arrhenius kinetics were observed by fluorescence anisotropy and enzymic measurements of mutants (but not wild‐types) of yeast, evidence based on membrane permeability and differential scanning calorimetry failed to support bulk lipid phase transitions as the cause for the discontinuities.
Interception of discrete oxygen species in aqueous media by cholesterol: Formation of cholesterol epoxides and secosterols
Authors: Gumulka Jerzy , Pyrek Jan St. , Smith Leland L.
Published: November 2006

The oxidation products of cholesterol oxidized by different dioxygen species, hydroxyl radical, or triatomic species ozone variously implicated in biological oxidtions are compared. Some products are unique to the oxygen species involved, whereas others, such as the isomeric cholesterol 5,6‐epoxides, are formed broadly by many oxygen species. The resolution of the isomeric cholesterol 5,6‐epoxides by capillary column gas chromatography on SE‐30 or SE‐54 has been achieved.
Utilization and metabolism of dietary sterols in the honey bee and the yellow fever mosquito
Authors: Svoboda James A. , Thompson Malcolm J. , Herbert Elton W. , Shortino Thomas J. , Szczepanik‐Vanleeuwen Patricia A.
Published: November 2006

The honey bee,Apis mellifera, does not convert C28 and C29 phytosterols to cholesterol as found in most previous studies of phytophagous or omnivorous insects, but instead the workers and queens selectively transfer 24‐methylenecholesterol, sitosterol and isofucosterol from their endogenous sterol pools to the brood larvae regardless of the sterol in the worker diet. Administering radiolabeled sterols by feeding and injection has made it possible to trace this selective transfer through a second generation of the honey bee. In further comparative sterol metabolism studies, the yellow fever mosquito,Aedes aegypti, was shown to be capable of dealkylating and converting a radiolabeled C29 dietary sterol ([14C] sitosterol) to cholesterol. Metabolic studies with several radiolabeled dietary sterols and an inhibitor of steroid metabolism in the yellow fever mosquito further verified this capability.
A new route to steroid ring C aromatization from readily available precursors
Authors: Anastasia Mario , Allevi Pietro , Fiecchi Alberto , Scala Antonio
Published: November 2006

3β‐Acetoxy‐8α,9α‐epoxy‐5α‐cholest‐14‐ene (1); 3β‐acetoxy‐14α,15α‐epoxy‐5α‐cholest‐8‐ene (2); 3β‐acetoxy‐5α‐cholest‐8(14)‐ene‐9α,15α‐diol (3); and 3β‐acetoxy‐5α‐cholesta‐8(14),9(11)‐dien‐15α‐ol (4) have been aromatized to a 9∶1 mixture of 3β‐hydroxy‐12‐methyl‐18‐nor‐5α,17β(H)‐cholesta‐8,11,13‐triene (5a) and 3β‐hydroxy‐12‐methyl‐18‐nor‐5α,17α(H)‐cholesta‐8,11,13‐triene (5b) in ethanol solution by using hydrochloric acid. The aromatization by action ofp‐toluenesulfonic acid gave mainly the epimer with the natural C‐17 configuration as the acetate 5c at the appropriatep‐toluenesulfonic acid concentration. 3β‐Acetoxy‐5α‐cholesta‐7,9(11),14‐triene (7a) and 3β‐hydroxy‐5α‐cholesta‐8,11,14‐triene (8a), 2 intermediary compounds in the aromatization, were isolated and characterized.
A1H NMR anomaly for steroidal alcohols? Reactions of a steroidal γ‐ketoacid
Authors: Piatak David M. , Ashline Kirk A. , Angelos George , Swenson Rebecca P. , Caspi Eliahu
Published: November 2006

The chemical and spectroscopic properties of several reaction products of 17β‐hydroxy‐1,3‐seco‐2‐nor‐5α‐estran‐1‐oic acid and 17β‐hydroxy‐1,3‐seco‐2‐nor‐4‐oxo‐5α‐estran‐1‐oic acid were examined and found to be atypical. For instance, the methyl ester of the first acid was resistant to basic hydrolysis conditions but partly hydrolyzed with 100% H2SO4. Reduction of the ester by LiA1H4 gave 1,3‐seco‐2‐nor‐5α‐estrane‐1,17β‐diol from which diacetate, ditosylate and 17‐monotosylate derivatives were prepared. The C‐1 methylene protons of each appeared as a singlet in 60, 100 and/or 270 MHz NMR spectra. The methyl ester and the diacetate of the diol were synthesized by alternate methods to verify the assigned structures. A 470‐MHz spectrum eventually resolved the C‐1 methylene protons of the monotysylate into the AB portion of an ABX pattern, further confirming the assigned structures. Also, 2,3‐seco‐1‐oxo‐5α‐estran‐17β‐ol 17‐nitrate was synthesized.
Constituents of human meconium: II. Identification of steroidal acids with 21 and 22 carbon atoms
Authors: Pyrek Jan St. , Sterzycki Roman , Lester Roger , Adcock Eugene
Published: November 2006

Monohydroxylated acid fraction isolated from human meconium was found to contain, in addition to C20 and C24 acids identified previously, three C22 bile acids‐(20S)‐3α‐hydroxy‐23,24‐bisnor‐5β‐cholan‐22‐oic, (20S)‐ and (20R)‐3β‐hydroxy‐23,24‐bisnor‐chol‐5‐en‐22‐oic, and one C21 acid‐3β‐hydroxypregn‐5‐en‐21‐oic. These compounds were identified by capillary gas chromatography‐mass spectrometry and by comparison with standards. It is postulated that these C22 acids, as well as the two monohydroxylated C24 bile acids (lithocholic and 3β‐hydroxychol‐5‐enoic) are produced in the maternal intestine by microbial flora and transferred to the fetus through the placenta.
Unusual urinary cholesterol metabolites following intracerebral injection of [4‐14C]cholesterol into rats: I. The minor14C‐metabolite
Authors: Ramsey R. B. , Nicholas H. J.
Published: November 2006

[4‐14C] Cholesterol injected intracerebrally into 10–12‐day‐old rats becomes localized largely in central nervous system myelin. If sufficient14C is injected, myelin cholesterol remains labeled for the rest of the rats' lives. In the course of the slow myelin cholesterol turnover that ensues, a unique series of cholesterol metabolites is excreted exclusively in the rats' urine. There is reason to believe that the metabolites are formed in the cental nervous system before entering the urine. This manuscript describes separation of the 2 urinary14C‐labeled metabolic types and isolation and identification of the minor14C‐labeled material which consists of cholesterol and 2 other sterols bound covalently to short‐chain peptides. The minor sterols have been tentatively identified as 24‐ and 26‐hydroxycholesterol. The sterol‐peptide combinations have been isolated from human male urine, also.
Modulation of prostaglandin synthesis in rat peritoneal macrophages with ω‐3 fatty acids,
Authors: Magrum Linda J. , Johnston Patricia V.
Published: November 2006

In view of the findings that ω3 fatty acids inhibit the synthesis of prostaglandins (PG) from arachidonic acid (20∶4ω6) and that among immunologically active cells, the macrophage, is a major producer of PG, we undertook a study of the effect of dietary α‐linolenic acid (18∶3ω3) on PG synthesis in the macrophage. Rats were fed purified diets containing either 10% corn oil (CO) or linseed oil (LO), providing either a low (1/32) or high (3.5/1) ratio of 18∶3ω3 to 18∶2ω6, respectively, for 6 weeks. Fatty acid analysis of macrophage phospholipids showed that there was an appreciable increase in the percentage of ω3 fatty acids and a decrease in the ω6 fatty acids in macrophages from rats fed the LO diet. The changes in fatty acid composition were associated with a significant decrease in the synthesis of prostaglandin E (PGE) by macrophages from rats fed the LO diet. Macrophages from rats fed the 2 dietary, oils did not differ in their ability to degrade PG, thus the difference in PG production appeared to be a consequence of decreased synthesis only. The dietarily induced changes in PGE synthesis were readily overcome in vitro by culturing macrophages with complexes of fat‐free bovine serum albumin and either 20∶4ω6 or 20∶5ω3.
Metabolism of platelet‐activating factor by blood platelets and plasma
Authors: Alam Iftekhar , Smith J. Bryan , Silver Melvin J.
Published: November 2006

High performance liquid chromatography in combination with a radioactivity detector was used to study the metabolism of platelet‐activating factor (1‐0‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine) by washed platelets, platelet‐free plasma and platelet‐rich plasma obtained from rabbits and humans. Degradation of platelet‐activating factor in plasma was completely inhibited by diisopropylfluorophosphate and was partially inhibited by ethylenediamine tetraacetic acid. Washed platelets metabolized platelet‐activating factor not only to the 2‐lyso compound but also, by reacylation of this lyso intermediate, to an analogue of platelet‐activating factor probably containing a long‐chain acyl group at thesn‐2 position. These transformations occurred, but to a lesser extent, in platelet‐rich plasma.
The effect of AY‐9944 on yeast sterol and sterol ester metabolism
Authors: Pereira Ravi , Holmlund Chester E. , Whittaker Noel
Published: November 2006

The effects of the hypocholesterolemic drug AY‐9944 (trans‐1,4‐bis(2‐chlorobenzylaminoethyl)cyclohexane dihydrochloride) at two concentrations (10−4M and 5×10−4M), on the synthesis of sterols and sterol esters bySaccharomyces cerevisiae were investigated. Although growth was not markedly affected by the drug, there was a decrease in the free sterol to sterol ester ratio with increased drug concentration. A concomitant increase in the saturated fatty acids esterified to sterol relative to the unsaturated fatty acids was also noted in response to increased drug concentration. Ergosterol accounted for 94.7% of the free sterol in the control culture and for 87.8% of the 5×10−4M drug‐treated culture, respectively. However, in the sterol ester fraction, the ergosterol content decreased from a value of 45.1% in the control culture to 2.4% in the 5×10−4M AY‐9944 treated culture. The sterol ester fraction simultaneously showed increased levels of the Δ8 sterol, fecosterol, in response to increased drug concentration from a 7.4% control value to 57.4% in the 5×10−4M drug‐treated culture. The accumulation of the Δ8 sterol suggests that the site of action of the drug is probably at the Δ8 to Δ7 isomerase step in the biosynthesis of ergosterol. The fact that ergosterol is retained as the major free sterol suggests a biological advantage to the retention of this particular sterol. In addition, the near normal growth in the presence of the drug, in spite of the occurrence of an altered sterol ester profile, indicates that the composition of the sterol ester fraction is not as critical as the free sterol fraction.
Human low density lipoprotein structure: Correlations with serum lipoprotein concentrations
Authors: Nelson Charles A. , Morris Manford D.
Published: November 2006

Human low density lipoproteins (LDL) were isolated and purified from individuals having widely differing serum lipid concentrations. Very low density lipoproteins (VLDL) and high density lipoproteins (HDL) were also isolated and quantitated. HDL2 and HDL3 were separated by flotation velocity in the analytical ultracentrifuge and their relative weight percent determined. The mean density of LDL from 41 individuals was determined by flotation velocity at two different solvent densities. The mean density of LDL was directly proportional to the triglyceride (r=0.65) and VLDL (r=0.50) concentrations and inversely proportional to the HDL (r=−0.55) and HDL2 (r=−0.74) concentrations (all significant at P<0.001). The mean molecular weight of LDL from 42 individuals was determined by flotation equilibrium centrifugation. The mean molecular weight of LDL was directly proportional to the HDL (r=0.49) and HDL2 (r=0.48) concentrations and inversely proportional to the serum triglyceride (r=−0.60) and VLDL (r=−0.48) concentrations (all significant at P<0.005 except triglyceride—P<0.001). The molecular weight of LDL was inversely proportional to its density, and thus inversely proportional to its protein/lipid ratio which was confirmed by composition measurements. The density and molecular weight of LDL had no relationship to the concentration of LDL (r=0.04 and 0.03).
How do polyunsaturated fatty acids lower plasma cholesterol levels?
Authors: Horrobin David F. , Manku Mehar S.
Published: November 2006

For 30 years it has been known that linoleic acid can lower elevated cholesterol levels. Large increases in linoleic acid have been widely recommended as a way of reducing the risk of cardiovascular disease. Such recommendations have resulted in major dietary shifts in some countries, including the USA. Yet the precise characteristics of the linoleic acid molecule which confer on it cholesterol‐lowering properties are unknown. γ‐Linolenic acid, the first essential fatty acid metabolite of linoleic acid, has been found to have cholesterol‐lowering actions ca. 170 times greater than the parent molecule, suggesting that linoleic acid must be converted to γ‐linolenic acid to exert its desirable effects on cholesterol metabolism. Aging, sex, diabetes mellitus, alchol, catecholamines andtrans fatty acids and saturated fats can all modulate the Δ‐6‐desaturase enzyme which converts linoleic acid to γ‐linolenic acid. This provides a possible unifying explanation for the actions of these known risk factors for cardiovascular disease.
The effect of developing solvents on lipid class quantification in chromarod thin layer chromatography/flame ionization detection
Authors: Parrish C. C. , Ackman R. G.
Published: November 2006

Undeveloped lipids on Chromarods give peaks of variable shape and of variable area when scanned through the flame ionization detector (FID). With a brief exposure to developing solvents of suitable polarity, it is possible to produce sharp peaks of less variable area without appreciably moving peak axes. Longer developments or developments in more polar solvent systems result in broader‐based peaks of lower area. These observations, based on many analyses of a triglyceride and of a ketone, suggest that the FID response of lipids can be modified according to their distribution around or along Chromarods.
Multiscale modeling and simulation of nanotube-based torsional oscillators
Authors: Xiao Shaoping , Hou Wenyi
Published: November 2006

In this paper, we propose the first numerical study of nanotube-based torsional oscillators via developing a new multiscale model. The edge-to-edge technique was employed in this multiscale method to couple the molecular model, i.e., nanotubes, and the continuum model, i.e., the metal paddle. Without losing accuracy, the metal paddle was treated as the rigid body in the continuum model. Torsional oscillators containing (10,0) nanotubes were mainly studied. We considered various initial angles of twist to depict linear/nonlinear characteristics of torsional oscillators. Furthermore, effects of vacancy defects and temperature on mechanisms of nanotube-based torsional oscillators were discussed.
Stabilizing polymorphic transitions of tristearin using diacylglycerols and sucrose polyesters
Authors: Oh Jun‐Hyun , McCurdy Alan R. , Clark Stephanie , Swanson Barry G.
Published: November 2006

The polymorphic transitions of synthesized tristearin in the presence of selected DAG or commercial sucrose polyesters (SPE) were investigated using DSC and X‐ray diffractiometry. The stabilizing effects of DAG and SPE on α to β transitions of tristearin were dependent on the chemical structures of additives such as FA chain length, saturation of FA, positions and number of FA on backbones. The addition of 1,2‐distearin (DS) or SPE containing 70% stearic acid with a hydrophile‐lipophile balance value of 1 (S‐170) to tristearin resulted in a significant stabilizing effect on the α to β transition during constant heating and storage of α forms at 53°C. The addition of 1,2‐DS or S‐170 also stabilized the β′ to β transitions of tristearin during constant heating and storage at 59°C. The addition of S‐170 exhibited greater stabilizing effects than the addition of 1,2‐DS during early stages of storage of α or β′ forms of tristearin. This study provides evidence of potential uses for SPE as additives to improve the quality and shelf life of foods containing fats by stabilizing the desirable α or β′ forms of fats.
Performance of two color scales for virgin olive oils: Influence of ripeness, variety, and harvest season
Authors: Melgosa M. , Huertas R. , Hita E. , Roa J. M. , Heredia F. J. , Alba J. , Moyano M. J.
Published: November 2006

The purpose of this investigation was to compare the performance of the bromthymol blue (BTB) method and the Uniform Oil Color Scale (UOCS) method with different sets of virgin olive oil samples from Andalusia (Spain), namely, 1213 samples from olives at three stages of ripeness, 1008 samples from eight olive varieties, and 1700 samples from olives harvested in four different crop seasons. All oils were extracted in the laboratory by the same procedure. The performance of the two color scales was compared using CIELAB color differences between the oil samples and the nearest standard from each scale. The UOCS performed at least 2.0 times better than the BTB for each of the three stages of olive ripeness, and the difference between the two color scales was statistically significant (P<0.001). The UOCS performed at least 1.3 times better than the BTB for each of the eight olive varieties studied, and the differences between the two color scales were statistically significant (P<0.02). The UOCS also performed at least 1.6 times better than the BTB for each of the four harvests analyzed, and the differences between the two color scales were statistically significant (P<0.001). Using the current oil samples, we could discern no substantial improvements to the UOCS standards.
Effect of storage on the original pigment profile of spanish virgin olive oil
Authors: Gallardo‐Guerrero Lourdes , Gandul‐Rojas Beatriz , Roca María , Mínguez‐Mosquera Ma Isabel
Published: November 2006

The present study was carried out on 12 virgin olive oils to determine whether one year's storage under mild conditions of 15°C and darkness affected the initial pigment composition of recently extracted virgin olive oil. Although the total pigment content remained constant, the individual contribution of each pigment changed. The acid compounds liberated from the fruits during the oil extraction process promote the beginning of chlorophyll pheophytinization and the isomerization of the 5,6‐epoxide groups of the minor xanthophylls. During the first 3 mon of storage, there was a generalized increase in pheophytinization that was different for each oil (P<0.01, Duncan test) but was not correlated with the free acidity measured in them. At the same time, isomerized xanthophylls and allomerized pheophytins increased slightly. Following this stage, pyropheophytin a (a pigment not present in the initial oils), was detected; its concentration increased during storage. There were no significant differences in the final percentages of pyropheophytin a among the 12 oils, and the concentration of this new compound represented around 3% of the chlorophyll fraction. The pheophytin a/pyropheophytin a ratio always exceeded 20. All these small pigment transformations were signs that the oil had been stored. The content and class of pigments present in virgin olive oil are authentic indicators of its history prior to marketing.
Interprovenance variation in the composition of Moringa oleifera oilseeds from Pakistan
Authors: Anwar Farooq , Ashraf Muhammad , Bhanger Muhammad Iqbal
Published: November 2006

Interprovenance variation was examined in the composition of Moringa oleifera oilseeds from Pakistan. The hexane‐extracted oil content of M. oleifera seeds harvested in the vicinity of the University of Agriculture, Faisalabad (Punjab, Pakistan), Bahauddin Zakariya University (Multan, Pakistan), and the University of Sindh, Jamshoro (Sindh, Pakistan), ranged from 33.23 to 40.90%. Protein, fiber, moisture, and ash contents were found to be 28.52–34.00, 6.52–7.50, 5.90–7.00, and 6.52–7.50%, respectively. The physical and chemical parameters of the extracted M. oleifera oils were as follows: iodine value, 67.20–71.00; refractive index (40°C), 1.4570–1.4637; density (24°C), 0.9012–0.9052 mg/mL; saponification value, 177.29–184.10; unsaponifiable matter, 0.60–0.83%; color (1‐in. cell), 1.00–1.50 R+20.00–30.00Y; smoke point, 198–202°C; and acidity (% as oleic acid), 0.50–0.74. Tocopherols (α, γ, and δ) accounted for 114.50–140.42, 58.05–86.70, and 54.20–75.16 mg/kg, respectively, of the oils. The induction periods (Rancimat, 20 L/h, 120°C) of the crude oils were 9.64–10.66 h and were reduced to 8.29–9.10 h after degumming. Specific extinctions at 232 and 270 nm were 1.80–2.50 and 0.54–1.00, respectively. The major sterol fractions of the oils were campesterol (14.13–17.00%), stigmasterol (15.88–19.00%), β‐sitosterol (45.30–53.20%), and Δ5‐avenasterol (8.84, 11.05%). The Moringa oils were found to contain high levels of oleic acid (up to 76.00%), followed by palmitic, stearic, behenic, and arachidic acids up to levels of 6.54, 6.00, 7.00, and 4.00%, respectively. Most of the parameters of M. oleifera oils indigenous to different agroclimatic regions of Pakistan were comparable to those of typical Moringa seed oils reported in the literature. The results of the present analytical study, compared with those for different vegetable oils, showed M. oleifera to be a potentially valuable oilseed crop.
A process for the preparation of food‐grade rice bran wax and the determination of its composition
Authors: Vali Shaik Ramjan , Ju Yi‐Hsu , Kaimal Thengumpillil Narayana Balagopala , Chern Yaw‐Terng
Published: November 2006

A two‐step method was developed for the preparation of food‐grade wax. The first step involved the solventdefatting of crude wax, which gave a dark brown, dry, powdered wax with a m.p. of 75–79°C. The major impurity in the defatted wax was the dark brown resinous matter. In the second step, the resinous matter was removed by bleaching with sodium borohydride in isopropanol. This step yielded a pale yellow, odorless wax with purity higher than 99% and with a m.p. of 80–83°C. The resinous matter was a mixture of aliphatic aldehydes, fatty alcohols, and FA. High‐temperature GC analysis of the purified rice bran wax indicated that it contained 11 major and 9 minor types of saturated wax esters. The major and minor peaks contained C44–C64 and C45–C59 wax esters, respectively. Rice bran wax was mainly a mixture of saturated esters of C22 and C24 FA and C24 to C40 aliphatic alcohols, with C24 and C30 being the predominant FA and fatty alcohol, respectively. The alcohol portion of the wax esters also contained small amounts of branched and odd carbon number fatty alcohols.
Preparation of monodisperse water‐in‐oil‐in‐water emulsions using microfluidization and straight‐through microchannel emulsification
Authors: Kobayashi Isao , Lou Xuefang , Mukataka Sukekuni , Nakajima Mitsutoshi
Published: November 2006

Water‐in‐soybean oil‐in‐water (W/O/W) emulsions with an internal water phase content of 10–30% (vol/vol) were prepared by a two‐step emulsification method using microfluidization and straight‐through microchannel (MC) emulsification. A straight‐through MC is a silicon array of micrometer‐sized through‐holes running through the plate. Microfluidization produced water‐in‐oil (W/O) emulsions with submicron water droplets of 0.15–0.26 μm in average diameter (dav,w/o) and 42–53% in CV (CVw/o) using tetraglycerin monolaurate condensed ricinoleic acid esters (TGCR) and polyglycerin polycondensed ricinoleic acid esters (PGPR) as surfactants dissolved in the oil phase. Thedav,w/oand viscosity of the W/O emulsions increased with an increase in internal water phase content. Straight‐through MC emulsification was performed using the W/O emulsions as the to‐be‐dispersed phase and polyoxyethylene (20) sorbitan monooleate (Tween®80) as a surfactant dissolved in the external water phase. Monodisperse W/O/W emulsions withdav,w/o/wof 39.0–41.0 μm and CVw/o/wbelow 5% were successfully formed from a straight‐through MC with an oblong section (42.8×13.3 μm), using the TGCR‐containing systems. Thedav,w/o/wof the monodisperse W/O/W emulsions decreased as the internal water phase content increased because of the increase in viscosity of the to‐be‐dispersed phase. Little leakage of the internal water droplets and no droplet coalescence or droplet break‐down were observed during straight‐through MC emulsification.
New technologies to determine solid fat content on‐line
Authors: Martini Silvana , Herrera Maria Lidia , Marangoni Alejandro
Published: November 2006

The determination of solid fat content (SFC) is an important analytical procedure in the food industry. The most common way to determine SFC is by low‐resolution pulsed NMR (p‐NMR). Although this technique is very sensitive and easy to use, it has the disadvantage that it cannot be used for on‐line measurements. The present work compares new technologies to determine SFC on‐line. On‐line ultrasonic spectroscopy and NMR‐MOUSE (NMR mobile universal surface explorer) techniques were compared with off‐line p‐NMR measurements and there was a good correlation between the values obtained. Ultrasonic measurements accurately described the SFC variation, whereas NMR‐MOUSE determinations need to be improved to some extent owing to a strong temperature and motion dependence. These two techniques can be used as on‐line methodologies to determine SFC during the crystallization of fats.
Diacylglycerol synthesis by enzymatic glycerolysis: Screening of commercially available lipases
Authors: Kristensen Janni Brogaard , Xu Xuebing , Mu Huiling
Published: November 2006

Seven lipases were screened for their ability to synthesize DAG in the glycerolysis of rapeseed oil. In batch reactions with free glycerol, the lipase carrier was of great importance for catalysis. Catalysis did not take place in reactions with lipases having hydrophilic carriers. The best DAG yield (approx. 60 wt%) was achieved with Novozym 435 and Lipase PS‐D after 7 h, and an equilibrium was obtained. Stepwise addition of glycerol allowed catalysis with Novozym CALB L (immobilized) to take place in spite of the hydrophilic carrier; however, the DAG yield was only 19 wt%. This result suggests that glycerol forms a layer around the hydrophilic lipase particles, limiting contact between the lipases and the hydrophobic oil phase. With glycerol absorbed on silica gel, all lipases catalyzed the glycerolysis reaction. Faster conversion of TAG was obtained with Lipase PS‐D, Lipase AK, and Lipase F‐AP15 than in reactions with free glycerol, but the DAG yield remained approximately 60–65 wt%. Nonspecific lipases yielded more 1,3‐DAG early in the reaction.
Enzymatic production of alkyl esters through alcoholysis: A critical evaluation of lipases and alcohols
Authors: Deng Li , Xu Xuebing , Haraldsson Gudmundur G. , Tan Tianwei , Wang Fang
Published: November 2006

This paper focuses on a detailed evaluation of commercially available immobilized lipases and simple monohydric alcohols for the production of alkyl esters from sunflower oil by enzymatic alcoholysis. Six lipases were tested with seven alcohols, including straight and branched‐chain primary and secondary alcohols. The reactions were conducted in a batch stirred reaction vessel using stoichiometric amounts of substrates under solvent‐free conditions. Dramatic differences in alcoholysis performance were observed among the different lipases. For most of the alcohols, Novozym 435 produced the highest yield of FA alkyl esters, with yields well over 90% for methanol, absolute ethanol, and 1‐propanol. Overall, 96% ethanol was the preferred alcohol for all lipases except Novozym 435, and ethanolysis reactions reached the maximal conversion efficiency. Increasing the water content in the system resulted in an increased degree of conversion for all lipases except Novozym 435. The secondary alcohol 2‐propanol significantly reduced the alcoholysis reaction with all lipases; however, the branch‐chain isobutanol was more advantageous than linear 1‐butanol for Novozym 435, Lipozyme RMIM, and Lipase PS‐C. Many commercial immobilized lipases are highly efficient and promising for the production of alkyl esters, offering high reaction yields and a simple operation process.
Polyurethane networks from formiated soy polyols: Synthesis and mechanical characterization
Authors: Monteavaro Luciane L. , da Silva Eduardo O. , Costa Ana Paula O. , Samios Dimitrios , Gerbase Annelise E. , Petzhold Cesar L.
Published: November 2006

Polyurethanes can be prepared using polyols obtained from vegetable oils in natura, such as castor oil, or from functionalized vegetable oils, such as hydroxylated soybean oil. These polyurethanes have different valuable properties, determined by their chemical composition and cross‐linking density. In this study, soy epoxy polyols with different OH contents were prepared through a one‐step reaction using the method of in situ performic acid generation. Polyols with OH functionalities from 1.9 to 3.2 were reacted in bulk with different diisocyanates at a NCO/OH molar ratio of 0.8 and 60°C for 24 h. Mechanical properties of the polyurethanes were determined by dynamic mechanical thermal analysis, hardness (Shore A), and swelling measurements. Polymer networks with glass‐transition temperatures (Tg) from −13 to 48°C were obtained. We observed that the higher the OH functionality of the polyols, the higher the Tg and cross‐linking density of the polyurethane network. The influence of diisocyanate structure (rigid or flexible chain), curing temperature, and curing reaction time on mechanical properties was also investigated.
Retardation effect of jojoba chain length on the chemical reactivity of the liquid wax
Authors: Gorodetsky Aleksandra , Zeltser Inna , Shani Arnon
Published: November 2006

Jojoba wax and its derivatives are slow‐reacting compounds. To elucidate the reasons for this phenomenon, we reacted jojoba mono‐ and bis‐epoxide and trans‐jojoba bis‐epoxide (C38–C44 long‐chain esters), as well as side chain esters of three steroid skeleton mono‐epoxide derivatives with NaI under acidic conditions to yield the corresponding iodohydrins, which then formed the respective bis‐keto (or mono‐ketone) derivatives. The kinetics, activation energies, and thermodynamic parameters of activation of nucleophilic epoxide opening and pinacol rearrangement were determined for all these compounds. The reaction rates of the jojoba derivatives were similar to those of two of the epoxides derived from the steroid skeleton compounds, and in the third case the steroid derivative reacted somewhat faster than all the rest. This pattern of rate retardation could stem either from folding of the long jojoba chain, resulting in steric hindrance around the reaction centers, or from repeated unproductive collisions along the long hydrocarbon chain of the jojoba wax (statistical effect). Our results appear to suggest that the multiple unsuccessful collisions were the dominant factor, although steric hindrance cannot be ruled out.
Oxidative stability of soybean oil fatty acid methyl esters by oil stability index (OSI)
Authors: Dunn Robert O.
Published: November 2006

Biodiesel, an alternative diesel fuel derived from transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long‐chain FA alkyl esters. During long‐term storage, oxidation caused by contact with air (autoxidation) presents a legitimate concern with respect to monitoring and maintaining fuel quality. Extensive oxidative degradation may compromise quality by adversely affecting kinematic viscosity, acid value, or PV. This work examines the oil stability index (OSI) as a parameter for monitoring the oxidative stability of soybean oil FAME (SME). SME samples from five separate sources and with varying storage and handling histories were analyzed for OSI at 60°C using an oxidative stability instrument. Results showed that OSI may be used to measure relative oxidative stability of SME samples as well as to differentiate between samples from different producers. Although addition of α‐tocopherol or TBHQ increased OSI, responses to these antioxidants varied with respect to SME sample. Variations in response to added antioxidant were attributed to aging and other effects that may have caused oxidative degradation in samples prior to acquisition for this study. Results showed that OSI was more sensitive than iodine value in detecting the effects of oxidative degradation in its early stages when monitoring SME during storage.
Oxidation kinetics of linoleic acid in the presence of saturated acyl l‐ascorbate
Authors: Watanabe Yoshiyuki , Ishido Eiichiro , Fang Xu , Adachi Shuji , Matsuno Ryuichi
Published: November 2006

The oxidation processes of linoleic acid (LA) in the presence of l‐ascorbic acid or saturated acyl l‐ascorbate additives were measured at various temperatures and molar ratios of the additive to LA. Higher oxidative stability of LA was observed at higher additive levels for all additives. The addition of the ascorbates lengthened the induction period for the oxidation of LA. An autocatalytic kinetic rate equation was used to model the oxidation processes of LA mixed with the ascorbates, and the dependence of the rate constant, k, on acyl‐chain carbon number was determined. At any temperature, the use of ascorbate additives decreased the k value for LA, and there was a slight tendency for k values to decrease with increasing acyl‐chain length. The apparent activation energy, Ea, and the frequency factor, k0, for the rate constant were determined from Arrhenius plots. The calculated Ea and k0 values also decreased with increasing ascorbate acyl‐chain length.
Influence of formulation on the thermal behavior of ice cream mix and ice cream
Authors: Granger C. , Schöppe A. , Leger A. , Barey P. , Cansell M.
Published: November 2006

The influence of fat and emulsifier types on particle size and thermal behavior of aged mixes and the corresponding ice creams was investigated. Mixes and ice creams based on partially unsaturated monodiglycerides (MDG) were characterized by an increased percentage of agglomerated fat globules compared with saturated MDG‐based system. DSC thermograms obtained for refined coconut oil in mix showed a displacement of the main crystallization event toward lower crystallization teperatures compared with fat in the bulk phase. This supercooling effect was more or less pronounced for the three other fats used (hydrogenated coconut oil, refined palm oil, and anhydrous milk fat). In emulsified systems, an additional exotherm was observed that was interpreted in terms of MDG crystallization. The fact that this peak appeared at different temperatures ranging from 32 to 41°C as a function of the fat selection suggested that different fat‐emulsifier interactions would occur. In the case of ice creams, although the water peak interfered with the fat peak, melting DSC curves allowed the discrimination between the fat types used in the formulation
Linalyl oleate as a frying oil autoxidation inhibitor
Authors: Onal‐Ulusoy Baran , Hammond Earl , White Pamela
Published: November 2006

Linalyl oleate (LO), an interesterification product of linalyl acetate (LA) and methyl oleate catalyzed with sodium methoxide, was studied to determine its effectiveness in retarding oxidative changes in soybean oil heated continuously at 180±5°C for 32 h. The identity of LO was established by GC‐MS and NMR. LO was tested at levels of 0.05 and 0.1% and compared with the more commonly used synthetic autoxidation inhibitor methyl silicone (MS) at levels of 5 and 10 ppm. FA changes and conjugated dienoic acid formation were monitored. First‐order kinetic equations were used to model the decreases in linoleate (18∶2)/palmitate and linolenate (18∶3)/palmitate ratios. Plots of the data show an inflection point at ∼11 h. Oils with either level of MS and LO had lower reaction rate constants before the inflection points, and lower conjugated diene values and higher 18∶2 and 18∶3 percentages at the end of the 32‐h heating period than did oil without additives and with LA. LO could replace methyl silicone in soybean oil during deep‐fat frying but at levels about 100 times greater. [We propose to use the term “autoxidation inhibitor” for substances that inhibit autoxidation when added to fats and oils at low concentrations and whose mechanism of action may be unknown. Some may wish to call such substances “antioxidants” but others wish to reserve this term for substances that end free radical chains by hydrogen radical donation. Some refer to methyl silicone as a “polymerization inhibitor”, but this term suggests more about its mechanism of action than seems warranted.]
Phytosterols in cereal by‐products
Authors: Jiang Yongzhi , Wang Tong
Published: November 2006

Phytosterols are hypocholesterolemic. Like corn fiber oil, the lipid extracts of certain cereal by‐products may be rich sources of these health‐promoting compounds. The objective of this research was to examine the phytosterol content and composition of various cereal by‐products. Total lipids in rice bran, wheat bran, wheat germ, durum wheat (bran and germ mixture), oat bran, oat hull, and corn fine fiber were extracted, and the sterol profiles of the extracted lipids were analyzed by GC. Rice bran contained the most lipids (22.2%), followed by wheat germ, durum wheat, oat bran, wheat bran, and oat hull; corn fine fiber contained the least amount of lipids (1.7%). Sitosterol, campesterol, and stigmasterol were the major phytosterols in these lipid extracts, whereas brassicasterol was detected only in wheat samples. Rice bran oil contained considerable amounts of cycloartenol and 24‐methylenecycloartanol, which were unique to these samples. Total sterol concentrations in extracted lipids were similar for rice bran, wheat bran, wheat germ, and durum wheat (21.3–15.1 mg/g), but they were very low in oat bran lipids and oat hull lipids (3.4 and 8.2 mg/g, respectively). Corn fine fiber lipids contained the highest amount of sterols (48.3 mg/g). Rice bran appears to be the best source of phytosterols, with the highest oil content and high concentration of sterols.
Effect of alkali on the refunctionalization of soy protein by hydrothermal cooking
Authors: Wang H. , Wang T. , Johnson L. A.
Published: November 2006

The effects of hydrothermal cooking (HTC) at alkaline conditions on refunctionalization of heat‐denatured protein of extruded‐expelled (EE) soy meals and on preparation of soy protein isolate (SPI) from EE soy meal were determined. Two HTC setups, flashing‐out HTC (without holding period) and HTC with holding for 42 s at 154°C, were evaluated. Alkali (NaOH) addition dramatically enhanced the refunctionalization of EE meal having an initial protein dispersibility index of 35. The more alkali added, the more refunctionalization occurred. Extensive refunctionalization was achieved at 0.6 mmol alkali/g EE meal, and additional improvement was small with more alkali. For both HTC setups, the solids and protein yields of SPI from alkali‐HTC‐treated EE meals were significantly higher than those from HTC without alkali addition. The yield of protein as SPI increased from 40 to 82% after HTC treatment at 0.6 mmol alkali/g EE meal compared with no alkali addition. The emulsification capacities of SPI after alkali‐HTC were similar to those from HTC without alkali. SPI from holding‐tube HTC‐treated EE meals had higher emulsification capacities than those prepared by flashing‐out HTC.
Surface roughness during storage of chocolate: Fractal analysis and possible mechanisms
Authors: Quevedo Roberto , Brown Christopher , Bouchon Pedro , Aguilera José M.
Published: November 2006

Laser scanning microscopy and fractal analysis were used to determine roughness in the surface of chocolate samples stored under cycling temperature conditions (16 to 26°C) for 24 d. The four samples varied in the source of fat: 100% cocoa butter (CB), lauric and nonlauric fat replacers, and CB with 2% of nonlauric fat replacer. The response variable was the area‐scale fractal complexity (Asfc), equivalent to a fractal dimension. Asfc increased with time to an asymptotic value (AV) in much the same way as whiteness index, both being accepted proxies of surface bloom. Images produced from topographical data revealed clearly the increase in roughness. Chocolate samples prepared with CB replacers exhibited an induction period and a slower rate of change in surface roughness than chocolate containing only CB. A linear relationship between a normalized roughness and the square root of time was followed by CB chocolate samples for the period before reaching AV. This result suggests that either diffusion or capillary flow may be the mechanism involved in fat migration to the surface.
Rubber seed oil quality assessment and authentication
Authors: Aigbodion A. I. , Bakare I. O.
Published: November 2006

Physicochemical and instrumental characterization of rubber (Hevea brasiliensis Müll. Arg.) seed oil (RSO) was carried out for the purposes of quality assessment, identification, and authentication. Properties such as color (Lovibond), specific gravity, percent FFA (as oleic acid), acid value, saponification value, iodine value, and viscosity were determined. FA composition and M.W. averages of RSO were determined using GLC and gel permeation chromatography (GPC), respectively. Structural features of RSO were also determined using FTIR, 1H NMR, and 13C NMR spectroscopy. The natural form of RSO is highly acidic (acid value≈43.6 mg KOH/g). The saturated FA are palmitic (17.50%) and stearic (4.82%), and the main unsaturated FA are oleic (25.33%), linoleic (37.50%), and linolenic (14.21%). The oil can be classified as semidrying. GPC shows an unusual peak that is due to a very high M.W. (≈38,800) fraction that is not found in the chromatogram of known vegetable oils and is therefore unique to RSO. FTIR, 1H NMR, and 13C NMR analyses confirmed that RSO is composed mainly of TAG of saturated and unsaturated FA. Functional groups such as carbonyl, olefinic unsaturation, esters, glyceryl, methylene, and terminal methyl that are present in vegetable oils are also present in RSO.
Preparation of fatty amide polyols via epoxidation of vegetable oil amides by oat seed peroxygenase
Authors: Piazza George J. , Foglia Thomas A.
Published: November 2006

Prior work has shown that oat (Avena sativa) seeds are a rich source of peroxygenase, an enzyme that promotes the oxidation of carbon‐carbon double bonds to form epoxides. Ground and defatted oat seeds were used as a low‐cost source of peroxygenase. A systematic study of the epoxidation of i‐butyl amides from linseed oil was conducted. Hexane was used as the primary component of the reaction media to eliminate the need for extraction. We found that the addition of a small amount of buffered water containing Tween 20 enhanced the epoxidation activity when using t‐butyl hydroperoxide and cumene hydroperoxide as oxidants. This activity could be further enhanced by the addition of isopropyl ether. Conditions for larger‐scale reactions were developed and applied to amides prepared from linseed, soybean, and canola oils. Because of enzymatic selectivity, the epoxidation of adjacent double bonds was low, and monoepoxides from the amides of oleate and linoleate predominated; the diepoxide, N‐i‐butyl‐9,10–15,16‐diepoxy‐12(Z)‐octadecenamide, was obtained from the amide of linolenate. The enzymatically epoxidized amides from the oils were hydrolyzed in dilute acid, and the distribution of the various classes of polyols was determined. Reflecting the high proportion of starting monoepoxides, saturated diols and diols with one double bond were the major polyols obtained from soybean and canola oils. Because linseed oil contains a high proportion of linolenate, polyols obtained from the epoxides of this oil had a major amount of the tetrol, N‐i‐butyl‐9,10,15,16‐tetrahydroxy‐12(Z)‐octadecenamide. In contrast, the components of polyols obtained from the hydrolysis of commercial epoxide preparations of soybean and linseed methyl esters followed by amide formation were primarily saturated diols and furan derivatives resulting from the presence of adjacent epoxide groups in these preparations.
Feed batch addition of saccharide during saccharide‐fatty acid esterification catalyzed by immobilized lipase: Time course, water activity, and kinetic model
Authors: Dang Hung T. , Obiri Oriana , Hayes Douglas G.
Published: November 2006

A conversion of 80–93% was achieved for esterification of oleic acid and fructose (or sucrose) catalyzed by immobilized Rhizomucor miehei lipase (Lipozyme IM; Novozymes, Franklinton, NC) at 65°C using near‐stoichiometric amounts of substrates. The product consisted of mono‐ and diester at a ratio of 9∶1 gg−1. The main obstacle for achieving a high rate of reaction, the poor miscibility of the substrates, was overcome by taking advantage of the greatly increased solubility of fructose as the proportion of ester increased. A phase diagram demonstrated that the solubility of fructose increased linearly from 0.002 to 0.07 to 0.13 gg−1 as the ester mass fraction increased from 0.00 to 0.47 to 0.80, respectively. Solvent (tert‐butanol) was present only during the first phase of the time course of the reaction to enhance fructose solubility and was allowed to evaporate away completely on reaching 25% conversion. A conversion higher than 80–93% could not be achieved by reducing the bioreactor's water content through use of vacuum pressure or water activity control. Water adsorption isotherms demonstrate the significant increase of equilibrium liquid phase water content as the reaction progressed, which was due to higher water adsorption by the monoester relative to oleic acid. Increased removal of liquid phase water may result in the loss of water from the lipase, resulting in a reduction of its biocatalytic activity. Initial rate experiments were used to derive a Ping‐Pong Bi Bi kinetic model that strongly agreed with measured data for the time course of the reaction. Lipozyme IM did not lose activity when employed for three successive fructose‐oleate esterification batch reactions or, equivalently, for a 24‐d reaction period.