bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of chemical interesterification on the physicochemical properties of complex fat systems. 3. Rheology and fractality of the crystal network
Authors: Marangoni Alejandro G. , Rousseau Dérick
Published: May 2007

Chemically interesterified and noninteresterified lard‐canola oil (LCO) and palm oil‐soybean oil blends ranging from 100% hardstock to 50%:50% hardstock/vegetable oil (w/w) were evaluated for hardness index (HI) using cone penetrometry and viscoelastic properties, such as shear storage modulus G′, using controlled‐stress rheometry. The HI and G′ of palm oil decreased upon addition of soybean oil, and chemical interesterification did not affect the HI or G′ of palm oil or palm oil‐soybean oil blends. The HI and G′ of lard decreased upon addition of canola oil, while chemical interesterification led to increases in both the HI and G′ of lard and LCO blends. All these effects were nonsolid fat content‐related, since solid fat content did not change substantially upon chemical interesterification. The microstructure of the fat crystal network in lard and palm oil was quantified rheologically using fractal analysis. Chemical interesterification did not affect the fractal dimension of the fat crystal networks in palm oil or lard (2.82 and 2.88, respectively). The rheological properties of the macroscopic systems were not affected by the spatial distribution of mass within their fat crystal networks. Moreover, our results suggest that the increases in G′ observed in lard upon chemical interesterification are potentially due to changes in the properties of the particles which make up the network (crystal habit).
The seed fatty acid composition and the distribution of Δ5‐olefinic acids in the triacylglycerols of some taxaceae (Taxus and Torreya)
Authors: Wolff Robert L. , Pédrono Frédérique , Marpeau Anne M. , Christie William W. , Gunstone Frank D.
Published: May 2007

The fatty acid compositions of the seeds from three Taxus (yew) species and one Torreya species belonging to the Taxaceae family [Taxus cuspidata (Japanese yew), T. chinensis (Chinese yew), T. baccata (English yew), and Torreya grandis (Chinese nutmeg yew)] have been established. These compositions were compared with those previously published for T. canadensis (Canadian yew) and Torreya nucifera. In Taxus species, as well as in Torreya species, Δ5‐olefinic acids are present in the seed lipids from all species analyzed. In Taxus, 5,9‐18:2 (taxoleic) acid is the prominent Δ5‐olefinic acid. It represents between 9.5 and 16.2% of total fatty acids. Other Δ5‐olefinic acids that occur in low amounts are 5,9,12‐18:3 (<3.5%), 5,11‐20:2 (<0.3%), 5,11,14‐20:3 (<2.2%), and 5,11,14,17‐20:4 (<0.3%) acids. In Torreya species, the major Δ5‐olefinic acid is 5,11,14‐20:3 (sciadonic) acid (between 6.7 and 11.2%). In contrast to Taxus species, the 5,9‐18:2 and 5,9,12‐18:3 acids are scarce in Torreya species: less than 0.1%. Also, the 9,12,15‐18:3 acid content is significantly lower in Torreya than in Taxus. The prominence of taxoleic acid among Δ5‐olefinic acids in the seed lipids is a unique characteristic of the genus Taxus that isolates it from all other Coniferophytes analyzed so far. However, this feature is not shared by other Taxaceae species, such as Torreya, and with regard to their seed fatty acid compositions, the family Taxaceae appears particularly heterogeneous. Our observations favor the hypothesis that in Gymnosperm seeds, there might exist two Δ5‐desaturases, one specific for unsaturated acids with a Δ9‐ethylenic bond (active in Taxus but not in Torreya), and the other specific for unsaturated acids with a Δ11‐ethylenic bond (active in Torreya but not in Taxus). Our data also highlight the importance of the elongase(s) in the metabolism of fatty acids in Gymnosperm seeds. 14‐Methylhexadecanoic acid, a habitual component of Pinaceae and Ginkgo biloba seed lipids, could not be detected in the Taxaceae studied here. 13C nuclear magnetic resonance spectroscopy of the oils from both genera has confirmed that Δ5‐olefinic acids are apparently excluded from the internal position of triacylglycerols, which is a characteristic common to all Gymnosperm species analyzed so far, and consequently of great antiquity in their life history.
Hydroxytyrosol and tyrosol as the main compounds found in the phenolic fraction of steam‐exploded olive stones
Authors: Fernández‐BolaɁos J. , Felizón B. , Brenes M. , Guillén R. , Heredia A.
Published: May 2007

The lignocellulosic by‐products, whole stones, and seed husks obtained from processing pitted table olives and oil olives were pretreated under various conditions of steam explosion, with and without previous acid impregnation. The various water‐soluble noncarbohydrate compounds generated during steam explosion, such as sugar degradation compounds (furfural and hydroxymethylfurfural), lignin degradation compounds (vanillic acid, syringic acid, vanillin, and syringaldehyde) and the simple phenolic compounds characteristic of olive fruit (tyrosol and hydroxytyrosol), were identified. The amount of hydroxytyrosol solubilized was higher than that of the other compounds, and increased with increasing steaming temperature and time. This suggests its presence as a structural component of the olive stone.
Identification of trans‐3,5‐dimethoxystilbene in commercial soy protein isolates
Authors: Boatright W. L. , St. Pyrek J. , Song J. , Crum A. D.
Published: May 2007

A previously unidentified component of the lipid extracts from commercial soy protein isolates (SPI) was analyzed by gas chromatography‐mass spectrometry (GC‐MS), high resolution mass spectrometry (HRMS), ultraviolet‐visible spectroscopy, and GC‐Fourier transform infrared spectrometry (FTIR). All these data, together with mass spectra of derivatives obtained by hydrogenation, indicated the structure of an unsymmetrical dimethoxystilbene. Subsequently, standard trans‐3,5‐dimethoxystilbene, synthesized according to established procedures, was found to have identical retention times and spectra by GC‐MS and GC‐FTIR with the compound isolated from commercial SPI. Laboratory SPI prepared from Probst, Stressland, and Burlison variety soybeans contained no detectable amounts of either trans‐3,5‐dimethoxystilbene or dehydroabietinal.
Studies on lipid and fatty acid compositions of puffer livers from Indian coastal waters with seasonal variation
Authors: Hazra Alok K. , Ghosh Somiranjan , Banerjee Shivaji , Mukherjee Biswapati
Published: May 2007

The puffer fishes Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris, and L. inermis of Indian coastal waters are wasted in huge quantity. The livers of these fishes were investigated for their lipid contents and fatty acid compositions in different seasons. It was found that monsoon season is the suitable time to obtain the maximal lipids (40.1–48.8%) from their livers, an amount similar to cod liver lipid content (39.5–55.0%). The fatty acids were mostly saturates and monoenes (60–70%). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations (7–12%) were high during monsoon season. Neutral lipids were the predominant lipid class (>80%) and comprised triglycerides (277–674 mg/g) and cholesterol (0.6–3.1 mg/g). Quality indices of puffer liver lipids, e.g., specific gravity, refractive index, acid value, iodine value, saponification value and unsaponifiable matter, were evaluated. Puffer liver lipids were quantitatively and qualitatively comparable to other commercially important marine fish oils. The overall study suggests the possibility of future commercial utilization of liver lipids from puffer, an unconventional, cheap, and easily available source.
5α,8α‐Epidioxycholest‐6‐en‐3‐β‐ol from three cone snails of the Indian ocean
Authors: Aknin M. , Viracaoundin I. , Faure R. , Gaydou E. M.
Published: May 2007

Three cone snail species (Conus ebraeus, C. leopardus, C. tessulatus, family Conidae) have been investigated for their sterolic fraction. Besides cholesterol, 5α,8α‐epidioxycholest‐6‐en‐3‐β‐ol has been isolated from each species and the structure determined using two‐dimensional nuclear magnetic resonance. The occurrence of 5α,8α‐epidioxycholest‐6‐en‐3‐β‐ol in high amounts in the crude extract (0.5%), constitutes an interesting source of this compound.
Physical refining of rice bran oil in relation to degumming and dewaxing
Authors: De B. K. , Bhattacharyya D. K.
Published: May 2007

Physical refining of rice bran oil (RBO) with acidity between 4.0 and 12.4% has been investigated in relation to degumming and dewaxing pretretments. It appears that physical refining after combined low‐temperature (10°C) degumming‐dewaxing produces good‐quality RBO with respect to color, free fatty acid, oryzanol, and tocopherol content.
Differential extraction of eleostearic acid‐rich lipid‐protein complexes in tung seeds
Authors: Dyer John M. , Tang Fuqiang , Chapital Dorselyn C. , Lax Alan R. , Shepherd Hurley S. , Shih Ding S. , Pepperman Armand B.
Published: May 2007

Lipid‐protein complexes were identified in the 104,000×g supernatant fraction of developing tung seeds. Incubation of this fraction with linoleoyl‐CoA promoted an increase of chloroform‐extractable lipids in a time‐dependent manner. High‐performance liquid chromatography analysis indicated that the extracted lipids were similar to mature tung oil triglycerides. Differential extraction using chloroform or chloroform/methanol indicated that linoleoyl‐CoA promoted extraction of pre‐existing lipids rather than de novo synthesis. An increase in extractable lipids was also observed after incubation with proteinase K. Isolation of lipid‐protein complexes by sucrose density centrifugation and analysis of proteins by gel electrophoresis revealed several proteins specifically associated with this lipid fraction.
Effect of fatty acid positional distribution and triacylglycerol composition on lipid by‐products formation during heat treatment: I. Polymer formation
Authors: Martin J. C. , Dobarganes M. C. , Nour M. , Marquez‐Ruiz G. , Christie W. W. , Lavillonnière F. , Sébédio J.L
Published: May 2007

Effects of the fatty acid positional distribution and of the triacylglycerol (TG) composition on polymerization of TG during heat treatment were studied. Diacid TG molecules, acylated only with linoleic acid or linolenic acid along with palmitic acid, and positioned either in the central position (PLP and PLnP, respectively) or in one of the two outer positions (PPL and PPLn, respectively) were synthesized. Monoacid TG, i.e., trilinolein and trilinolenin, were also synthesized and mixed with tripalmitin in a 1:2 ratio. These model TG were also compared to TG models that consisted of a canola oil and its randomized counterpart, whose fatty acid positional distribution and TG composition were determined by means of high‐performance liquid chromatography (HPLC). After heating, the polymer content and composition were evaluated by HPLC‐size exclusion chromatography. Both pure TG and the canola oil models showed that acylation of polyunsaturated acids in the central position was protective against polymerization, although the effect was mainly observed with linolenic acid. The synthetic‐TG study showed that the monoacid TG species exhibited higher sensitivity toward polymerization than the diacid species. The slight differences in the TG species between both canola oils did not allow observation of such a relationship with regard to TG composition.
Effect of fatty acid positional distribution and triacylglycerol composition on lipid by‐products formation during heat treatment: II. Trans isomers
Authors: Martin J. C. , Nour M. , Lavillonnière F. , Sébédio J.L
Published: May 2007

This study examined the effect of the fatty acid positional distribution and of the triacylglycerol (TG) composition on heat‐induced trans isomerization of linoleic and linolenic acids. For this, we synthesized diacid TG molecules that were acylated only with linoleic acid (L) or with linolenic acid (Ln) along with palmitic acid (P). The fatty acid of interest was positioned either in the central position (PLP and PLnP, respectively) or in one of the two outer positions (PPL and PPLn, respectively). Monoacid TG, i.e., trilinolein and trilinolenin, were also synthesized and mixed with tripalmitin in a 1:2 ratio. This model TG was also compared to another TG model, which consisted of a canola oil and its randomized counterpart whose fatty acid positional distribution and TG composition were determined by means of high‐performance liquid chromatography. After heating, the content of trans isomers was determined by gas‐liquid chromatography with a polar capillary column. In model TG, polyunsaturated fatty acids in monoacid TG (LLL and LnLnLn) exhibited the highest degree of isomerization, compared to diacid TG, and this effect was greatest at 220°C. At this temperature, an effect of the TG structure was observed only with linolenic acid. In that situation, 18:3n‐3 acylated in the central position of the TG molecule (PLnP) displayed the highest sensitivity to trans geometrical isomerization. Although to a lesser extent, the same trends as for the pure TG model were observed with the canola oil model with regard to the influence of the fatty acid positional distribution and TG molecular species.
Fatty acid composition and contents of trans monounsaturated fatty acids in frying fats, and in margarines and shortenings marketed in Denmark
Authors: Ovesen Lars , Leth Torben , Hansen Kirsten
Published: May 2007

This study examined trans monounsaturated fatty acid contents in all margarines and shortenings marketed in Denmark, and in frying fats used by the fast‐food restaurants Burger King and McDonald's. Trans C18:1 content was 4.1±3.8% (g per 100 g fatty acids) in hard margarines, significantly higher than the content in soft margarines of 0.4±0.8%. Shortenings had an even higher content of trans C18:1, 6.7±2.3%, than the hard margarines. Margarines and shortenings with high contents of long‐chain fatty acids had about 20% total trans monoenoic of which close to 50% were made up of trans long‐chain fatty acids. Both fast‐food frying fats contained large amounts of trans C18:1, 21.9±2.9% in Burger King and 16.6±0.4% in McDonald's. In Denmark the per capita supply of trans C18:1 from margarines and shortenings and frying fats has decreased steadily during recent years. The supply of trans C18:1 from margarines and shortenings in the Danish diet is now 1.1 g per day.
Effects of oilseed storage proteins on aflatoxin production by aspergillus flavus
Authors: Mellon Jay E. , Cotty Peter J.
Published: May 2007

Potential involvement of seed storage proteins in susceptibility to aflatoxin contamination was assessed with in vitro tests. Initially, two oilseed storage proteins [cottonseed storage protein (CSP) and zein] were compared with bovine serum albumin (BSA) and collagen. Supplementation of a complete defined medium with either oilseed storage protein resulted in significantly more aflatoxin production by Aspergillus flavus than supplementation with either BSA or collagen. Little or no aflatoxin was produced when either BSA, CSP, or zein was employed (at 0.5%) as both the sole carbon and the sole nitrogen source. Media with collagen (0.5%) as the sole nitrogen and carbon source supported aflatoxin production similar to the complete defined medium. Although lower than levels observed with defined medium, aflatoxin production increased with both increasing CSP concentration (0 to 2.0%) and increasing zein concentration (0 to 6.0%) when these proteins served as both the sole carbon and sole nitrogen source. Denaturing polyacrylamide gel electrophoresis and protease activity assays indicated that fungal acquisition of protein carbon was probably via hydrolysis mediated by the 35 kD metalloprotease of A. flavus. Media lacking nitrogen but containing sucrose (5.0%) and supplemented with either zein (1.7%) or CSP (2.0%) supported three‐ to eightfold more aflatoxin production than the complete defined medium. The results suggest seed storage proteins, when present with an accessible carbon source, may predispose oilseed crops to support production of high levels of aflatoxins by A. flavus during seed infection.
Determination of unsaturated fatty acid composition by high‐resolution nuclear magnetic resonance spectroscopy
Authors: Miyake Yuko , Yokomizo Kazuhisa , Matsuzaki Narihide
Published: May 2007

High‐resolution nuclear magnetic resonance (NMR) spectroscopy provides useful data for analyzing fatty acid compositions of edible vegetable oils. Quantitation of each fatty acid was carried out by evaluation of particular peaks. According to the 1H NMR method, terminal methyl protons, divinyl protons, and allyl protons are useful to calculate linolenic acid, linoleic acid, and oleic acid, respectively. The ω‐2 carbon, divinyl carbon, and allylic carbons were used for calculation of these acids by the 13C NMR method. Compositional results obtained by NMR coincided well with those of the conventional gas chromatography (GC) method. Results from 13C NMR were in better agreement with those from GC than were the results obtained by the 1H NMR method.
Quantitative determination of hydroperoxides by fourier transform infrared spectroscopy with a disposable infrared card
Authors: Ma K. , van de Voort F. R. , Ismail A. A. , Sedman J.
Published: May 2007

Disposable polyethylene infrared cards (3M IR cards) were investigated for their suitability for the quantitative determination of peroxide value (PV) in edible oils relative to a conventional transmission flow cell. The analysis is based on the stoichiometric reaction of triphenylphosphine (TPP) with hydroperoxides to produce triphenylphosphine oxide (TPPO). Preliminary work indicated that the cards, although relatively consistent in their pathlength (±1%), had an overall effective pathlength variation of ±∼5%, caused by variability in loading of the oil onto the cards. This loading variability was reduced to <0.5% by developing a normalization protocol that is based on the peak height of the ester linkage carbonyl overtone band at 3475 cm−1, which allowed one to obtain consistent and reproducible spectra. The standard PV calibration approach, based on the TPPO peak height at 542 cm−1, failed because of unanticipated card fringing in the region where the measurements were being made. However, the development of a partial‐least‐squares (PLS) calibration provided a means of eliminating the interfering effect of the fringes and allowed the TPPO band to be measured accurately. An alternate approach to the standardized addition of TPP reagent to the oil was also investigated by impregnating the 3M IR cards with TPP, thus allowing the reaction to take place in situ. The spectral analysis protocols developed (normalization/calibration) were programmed to automate the PV analysis completely. The 3M card‐based Fourier transform infrared PV methods developed were validated by analyzing oxidized oils and comparing the PV predictions obtained to those obtained in a 100‐µm KCI flow cell. Both card methods performed well in their ability to predict PV. The TPP‐impregnated 3M card method reproduced the flow cell PV data to within ±1.12 PV, whereas the method with an unimpregnated card was accurate to ±0.92 PV over the calibrated range (0–25 PV). Our results indicate that, with spectral normalization and the use of a PLS calibration, quantitative PV data, comparable to those obtained with a flow cell, can be provided by the 3M IR card. With the analytical protocol preprogrammed, the disposable 3M card provides a simple, rapid and convenient means of carrying out PV analyses, suitable for quality control laboratories, taking about 2–3 min per analysis.
Thermal degradation of single methyl oleate hydroperoxides obtained by photosensitized oxidation
Authors: Lercker Giovanni , Bortolomeazzi Renzo , Pizzale Lorena
Published: May 2007

A peroxidation mixture containing methyl 9‐ and 10‐hydroperoxy‐trans‐octadecenoates (MOHP) was obtained by singlet oxygen oxidation of methyl oleate. The two hydroperoxides were collected by solid phase extraction and purified separately by high‐performance liquid chromatography. Identification and single‐isomer purity evaluations were carried out by comparing the chromatographic and gas chromatography‐mass spectrometry parameters of the corresponding reduced hydroxy derivatives. Each purified MOHP was thermally degraded and new reaction mechanisms were proposed from the identification of the degradation products. Thermal rearrangement of each hydroperoxide isomer involved an allylic 3‐carbon intermediate before further degradation steps. The two MOHP isomers obtained from singlet oxygen oxidation produced all eight hydroperoxide isomers by thermal degradation in the condensed phase at high temperature (200°C). This result supports the assumption of singlet oxygen as a promoter of the first steps of oxidation of food lipids and also reconsiders the Khan mechanism.
Oxidative and flavor stability of oil from lipoxygenase‐free soybeans
Authors: King J. M. , Svendsen L. K. , Fehr W. R. , Narvel J. M. , White P. J.
Published: May 2007

Soybeans that lack or contain three lipoxygenase (LOX) isozymes, LOX‐1, LOX‐2, and LOX‐3, were evaluated for oxidative and flavor stability at 60°C in the dark and at 35°C in the light. Although the two types of soybeans had a similar genetic background, there were significant differences (P ≤ 0.01) in fatty acid percentages between the lipoxygenase‐free and normal oils before and after storage at both temperatures. The linolenic acid content of oil from LOX‐free germplasm before storage averaged 7.2%, while normal lines averaged 6.6%. The linoleic acid content after storage averaged 6.9% for LOX‐free and 6.6% for normal oils. LOX‐free oil was not significantly different from normal oil in flavor, as judged by a sensory panel, or in concentrations of volatiles during storage at either storage condition. LOX‐free oil had less hexanal than normal oil before storage, but had significantly greater (P ≤ 0.05) levels after storage for two weeks at 35°C. Peroxide values of oil from LOX‐free soybeans were significantly greater (P ≤ 0.01) than oil from the normal soybean after storage at 60 and 35°C. LOX‐free oil had significantly greater (P ≤ 0.01) levels of α‐, β‐, and γ‐tocopherols. In general, oil from LOX‐free soybeans did not have improved flavor or oxidative stability. Differences between the two oil types in peroxide value and in production of a few volatiles were probably a result of the differences in initial fatty acid composition.
Effect of initial slight oxidation on stability of polyunsaturated fatty acid/protein mixtures under controlled atmospheres
Authors: Alaiz Manuel , Hidalgo Francisco J. , Zamora Rosario
Published: May 2007

A mixture of unsaturated fatty acids (FA), mainly linolenic acid, and bovine serum albumin (BSA) was incubated under several different atmospheres to study the effect of these atmospheres on the stability of FA to oxidation. Four experiments were carried out simultaneously, which consisted of the incubation of the FA/BSA mixture under air, nitrogen, air in the presence of 200 ppm of butylated hydroxytoluene, and air for 6 h and then under nitrogen. The four experiments were tested for lipid oxidation and color changes by measuring absorbances at 234 and 270 nm, formation of thiobarbituric acid‐reactive substances, and color differences and yellowness index. The samples that were oxidized with air before storage under nitrogen were the most stable against lipid peroxidation and exhibited the smallest color changes. These results suggest that a slight and controlled lipid oxidation improved the oxidative stability of FA/BSA mixtures.
Isolation of an active peptide fragment from human serum albumin and its synergism with α‐tocopherol
Authors: Hatate Hideo
Published: May 2007

An active peptide was isolated from hydrolysates of human serum albumin. This peptide was initially isolated by gel permeation chromatography and subsequent reversed‐phase high‐performance liquid chromatography. This active peptide, composed of 10 amino acid residues, was further hydrolyzed with a lysyl endopeptidase to give two peptide fragments. Only one fragment, identified as the tetrapeptide Leu‐Gln‐His‐Lys, was found to have activity comparable to the original peptide and corresponded to the amino acid residues 103–106 of human serum albumin. Among these four amino acid residues, the His‐Lys sequence seemed to be important in the occurrence of potent activity by comparison of the structural similarity with another active tetrapeptide, Asp‐Thr‐His‐Lys, which had been previously isolated from bovine serum albumin hydrolysates. In addition, the active fragment showed potent synergism by preventing consumption of α‐tocopherol during the autoxidation of linoleic acid.
Antioxidative activity of green tea catechin extract compared with that of rosemary extract
Authors: Chen Zhen‐Yu , Wang Li‐Ya , Chan Ping Tim , Zhang Zesheng , Chung Hau Yin , Liang Chao
Published: May 2007

This study compared the antioxidative activity of green tea catechin (GTC) extract with that of rosemary extract in canola oil, pork lard, and chicken fat. The GTC extract was obtained from jasmine and longjing green teas and mainly consisted of four epicatechin isomers including (−)epigallocatechin gallate (EGCG), (−)epigallocatechin (EGC), (−)epicatechin (EC), and (−)epicatechin gallate (ECG). The oxidation was conducted at 100 ± 2°C by monitoring oxygen uptake. The oxygen consumption test demonstrated that GTC extract was much more effective than the rosemary extract against lipid oxidation in canola oil, pork lard, and chicken fat under the conditions of the present study. Together with our previous study which showed that GTC extract was more protective than butylated hydroxytoluene as an antioxidant, these results suggest that GTC as a mixture of EGCG, EGC, EC, and ECG may serve as an antioxidant in processed foods.
Influence of lipase‐catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols
Authors: Moussata Charment O. , Akoh Casimir C.
Published: May 2007

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n‐6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n‐9) acid contents increased at the sn‐2 position of triacylglycerols, whereas 18:2n‐6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase‐interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n‐9 in the blends. The ratio of 18:1n‐9/18:2n‐6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.
Efficient intraliposomal entrapment of hydrophilic platinum oligonuclear complexes
Authors: Ogawa Yoshikatsu , Yamazaki Yoshimitsu , Kodaka Masato , Okuno Hiroaki
Published: May 2007

A simple method for intraliposomal entrapment of platinum complexes is presented, where hydrophilic platinum oligonuclear complexes, 1‐methyluracil green (MeUG), uridine green (UdG) and uridine blue (UdB), are included inside liposomes and allowed to react with bilayer lipids. The liposomes prepared in this method exhibit higher entrapment efficiency and higher distribution to organs (liver, kidney, spleen, lung) and blood (but not B16 cancer cells) than those prepared from mononuclear Pt complexes [cis‐diamminedichloroplatinum, cis‐diammine‐1,1′‐dicarboxylatocyclobutaneplatinum, and cis‐dichloro‐cis‐dihydroxy‐trans‐bis(isopropylamine)platinum)].
Fast formation of high‐purity methyl esters from vegetable oils
Authors: Boocock David G. B. , Konar Samir K. , Mao V. , Lee C. , Buligan Sonia
Published: May 2007

Experiments have confirmed that the base‐catalyzed methanolysis of vegetable oils occurs much slower than butanolysis because of the two liquid phases initially present in the former reaction. For the same reason, second‐order kinetics are not followed. The use of a cosolvent such as tetrahydrofuran or methyl tertiary butyl ether speeds up methanolysis considerably. However, like one‐phase butanolysis, one‐phase methanolysis initially exhibits a rapid formation of ester, but then slows drastically. Experiments show that the half‐life of the hydroxide catalyst is too long to explain the sudden slowing of the reaction. Similarly, lower rate constants for the methylation of the mono‐ and diglycerides are not a reasonable explanation. Instead the cause has been identified as the fall in polarity which results from the mixing of the nonpolar oil with the methanol. This lowers the effectiveness of both hydroxide and alkoxide catalysts. Increasing the methanol/oil molar ratio to 27 in the one‐phase system raises the polarity such that the methyl ester content of the ester product exceeds 99.4 wt% in 7 min. This has obvious implications for the size of new methyl ester plants as well as the capacity of existing facilities.
Low‐temperature property and engine performance evaluation of ethyl and isopropyl esters of tallow and grease
Authors: Wu Wen‐Hsin , Foglia Thomas A. , Marmer William N. , Dunn Robert O. , Goering Carroll E. , Briggs Thomas E.
Published: May 2007

Three monoalkyl fatty acid esters derived from tallow and grease were prepared by lipase‐catalyzed transesterification and evaluated as prospective diesel engine fuels. The low‐temperature properties of the esters, both neat and as 20% blends in No. 2 diesel fuel, were evaluated. Those properties included cloud point, pour point, cold filter plugging point, low‐temperature flow test, and crystallization onset temperature. Other properties of the esters, such as kinematic viscosity, heating value, and calculated cetane number, also were determined. All three esters had acceptable physical and low‐temperature properties, as well as acceptable fuel properties at the 20% level in diesel blends. Engine performance and emissions for the ester blends were determined in a direct‐injection, matched two‐cylinder diesel engine. Among the monoalkyl esters studied, ethyl greasate had better properties and engine performance characteristics than the two tallow esters. For the latter esters, isopropyl tallowate had better properties than ethyl tallowate.
Production of specific‐structured lipids by enzymatic interesterification: Elucidation of acyl migration by response surface design
Authors: Xu X. , Skands A. R. H. , Høy C. ‐E. , Mu H. , Balchen S. , Adler‐Nissen J.
Published: May 2007

Production of specific‐structured lipids (SSL) by lipase‐catalyzed interesterification has been attracting more and more attention recently. However, it was found that acyl migration occurs during the reaction and causes the production of byproducts. In this paper, the elucidation of acyl migration by response surface design was carried out in the Lipozyme IM (Rhizomucor miehei)‐catalyzed interesterification between rapeseed oil and capric acid in solvent‐free media. A five‐factor response surface design was used to evaluate the influence of five major factors and their relationships. The five factors, water content, reaction temperature, enzyme load, reaction time and substrate ratio, were varied at three levels together with two star points. All parameters besides substrate ratio had strong positive influences on acyl migration, and reaction temperature was most significant. The contour plots clearly show the interactions between the parameters. The migration rates of different fatty acids were also compared from three different sets of experiments during the lipase‐catalyzed reaction. The best‐fitting quadratic response surface model was determined by regression and backward elimination. The coefficients of determination (R2) of the model were 0.996 and 0.981 for Q2 value. The results show that the fitted quadratic model satisfactorily expresses acyl migration for the enzymatic interesterification in the batch reactor used.
Production of specific‐structured triacylglycerols by lipase‐catalyzed interesterification in a laboratory‐scale continuous reactor
Authors: Mu H. , Xu X. , Høy C. ‐E.
Published: May 2007

A laboratory‐scale continuous reactor was constructed for production of specific structured triacylglycerols containing essential fatty acids and medium‐chain fatty acids (MCFA) in the sn‐2 and sn‐1,3 positions, respectively. Different parameters in the lipase‐catalyzed interesterification were elucidated. The reaction time was the most critical factor. Longer reaction time resulted in higher yield, but was accompanied by increased acyl migration. The concentration of the desired triacylglycerol (TAG) in the interesterification product increased significantly with reaction time, even though there was only a slight increase in the incorporation of MCFA. Increased reactor temperature and content of MCFA in the initial reaction substrate improved the incorporation of MCFA and the yield of the desired TAG in the products. Little increase of acyl migration was observed. Increasing the water content from 0.03 to 0.11% (w/w substrate) in the reaction substrate had almost no effect on either the incorporation or the migration of MCFA, or on the resulting composition of TAG products and their free fatty acid content. Therefore, we conclude that the water in the original reaction substrate is sufficient to maintain the enzyme activity in this continuous reactor. Since the substrates were contacted with a large amount of lipase, the reaction time was shorter compared with a batch reactor, resulting in reduced acyl migration. Consequently, the purity of the specific structured TAG produced was improved. Interesterification of various vegetable oils and caprylic acid also demonstrated that the incorporation was affected by the reaction media. Reaction conditions for lipase‐catalyzed synthesis of specific structured TAG should be optimized according to the oil in use.
Increasing short‐chain fatty acid yield during lipase hydrolysis of a butterfat fraction with periodic aqueous extraction
Authors: Lencki Robert W. , Smink Natasja , Snelting Heleen , Arul Joseph
Published: May 2007

Factors affecting the release of short‐chain fatty acids during hydrolysis of a butterfat fraction with a 1,3‐positional and short‐chain‐specific Penicillium roqueforti lipase were investigated. When a short‐chain triglyceride fraction was used as substrate, as opposed to whole butterfat, the ratio of desirable flavor short‐chain free fatty acids (FFA) to undesirable medium‐chain FFA in the FFA fraction increased from 0.75 to 1.80. However, with both substrates, FFA accumulation eventually led to lipase inhibition and limited the total amount of triglyceride hydrolysis. This inhibition phenomenon was principally due to product inhibition. Periodically extracting the FFA with a buffer solution minimized this inhibition phenomenon, thereby significantly increasing lipase activity and the degree of triglyceride hydrolysis. Thus, on‐line extraction of FFA in lipase reactors has the potential of greatly increasing system productivity.
Parameters affecting the synthesis of geranyl butyrate by esterase 30,000 from Mucor miehei
Authors: Karra‐Chaabouni Maha , Pulvin Sylviane , Touraud Didier , Thomas Daniel
Published: May 2007

The factors affecting the synthesis of geranyl butyrate by esterase 30,000 of Mucor miehei were studied in a solvent‐free system. The effects of substrate molar ratio, temperature, agitation speed, and initial addition of water were investigated. The equimolar ratio was most interesting for ester production in batch. There were no diffusion limitations, and the reaction could be realized at low agitation. The catalytic activity of the enzyme was irreversibly deactivated at 60°C, and the initial addition of water decreased the rate of conversion after 75 h of reaction. The enzyme activity increased with increased linear chainlength of the acid and was also affected by the alcohol structure. Esterase 30,000 gave the highest conversion of butyric acid with hexanol and terpenic alcohols (citronellol, nerol) and the lowest with the secondary alcohol (2‐hexanol). Finally, five other industrial enzymatic preparations were investigated for their ability to synthesize geranyl butyrate and to hydrolyze olive oil. We observed, for the lipase from Rhizopus javanicua, that there is no relationship between hydrolytic and synthetic activities; this example shows that the hydrolytic lipase activity data cannot predict the capability of lipases in esterification reactions.
Enzymatic enrichment of arachidonic acid from Mortierella single‐cell oil
Authors: Shimada Yuji , Sugihara Akio , Minamigawa Yumi , Higashiyama Kenichi , Akimoto Kengo , Fujikawa Shigeaki , Komemushi Sadao , Tominaga Yoshio
Published: May 2007

An attempt was made to enrich arachidonic acid (AA) from Mortierella single‐cell oil, which had an AA content of 25%. The first step involved the hydrolysis of the oil with Pseudomonas sp. lipase. A mixture of 2.5 g oil, 2.5 g water, and 4000 units (U) Pseudomonas lipase was incubated at 40°C for 40 h with stirring at 500 rpm. The hydrolysis was 90% complete after 40 h, and the resulting free fatty acids (FFA) were extracted with n‐hexane (AA content, 25%; recovery of AA, 91%). The second step involved the selective esterification of the fatty acids with lauryl alcohol and Candida rugosa lipase. A mixture of 3.5 g fatty acids/lauryl alcohol (1:1, mol/mol), 1.5 g water, and 1000 U Candida lipase was incubated at 30°C for 16 h with stirring at 500 rpm. Under these conditions, 55% of the fatty acids were esterified, and the AA content in the FFA fraction was raised to 51% with a 92% yield. The long‐chain saturated fatty acids in the FFA fraction were eliminated as urea adducts. This procedure raised the AA content to 63%. To further elevate the AA content, the fatty acids were esterified again in the same manner with Candida lipase. The repeated esterification raised the AA content to 75% with a recovery of 71% of its initial content.
Chloramine T with iodine: A new reagent to determine the iodine value fo edible oils
Authors: Nagendrappa Giddappa , Urs S. Subramanya Raj , Rajalakshmi S.
Published: May 2007

Chloramine T (N‐chloro‐p‐toluenesulfonamide sodium salt) and iodine (2:1, w/w) in carbon tetrachloride and acetic acid (1:1, vol/vol), referred to as reagent (I) was found to be effective for the determination of Iodine value of edible oils. Reagent (I) reacted quantitatively with the double bonds of oils of known weight. The reagent left unreacted after 20–25 min was titrated against standard sodium thiosulfate solution (0.04 M) in presence of potassium iodide (10%, 5 mL). The difference in volume of sodium thiosulfate solution consumed by reagent (I) without and with oil was a basis to calculate the iodine value of oils used. The iodine values of different oils were also determined separately following the standard procedure of Wijs, and calculated iodine value was obtained from the gas chromatographic profile of fatty acids. The iodine value obtained by the new method was in agreement with the results of the standard methods. The results obtained indicate that the method could be a complementary or an alternative to the Wijs method.
Anomalous high iodine value of squalene and the impact on iodine values of shark liver oils
Authors: Ackman R. G. , Macpherson E. , Timmins A.
Published: May 2007

Squalene has six ethylenic bonds, but the experimental iodine values in two different solvent systems—chloroform and cyclohexane/acetic acid—were 25% higher than the theoretical values. We propose that this results from an additional halogen adding at each of the two terminal ethylenic bonds carrying two methyl groups. In the solvent system of cyclohexane alone, the excess is only 3–4% greater than the theoretical. Mixtures of squalene in seal oil confirmed the additivity of the experimental squalene high iodine value and the seal oil fatty acid iodine value with reasonable accuracy but depended on the skill of the operator in obtaining the titration end point for cyclohexane/acetic acid. This observation has particular relevance for shark liver oils and olive oils.
Surface tension of protein and insoluble lipids at the air‐aqueous phase interface
Authors: NiɁo Ma Rosario Rodríguez , Patino Juan M. Rodríguez
Published: May 2007

The surface activity of bovine serum albumin (BSA) in water and aqueous solutions of ethanol (0.5, 1.0, and 2.0 M) and sucrose (0.5 and 1.0 M) has been investigated over a range of protein concentrations (5–1.10−5, % w/w). The surface tension data were determined by the Wilhelmy plate method. Surface data at low protein concentrations indicate a low surface activity, which rises to a plateau as the monolayer is saturated at higher protein concentrations. The protein concentration and surface tension at the plateau depend on the aqueous phase composition. The effect of aqueous phase composition on BSA‐lipid interactions has been investigated by spreading an insoluble lipid (monostearin or monoolein) on a film of BSA previously adsorbed on the interface. The existence of protein‐lipid interactions depends on the protein/lipid ratio. The surface activity of mixed BSA‐lipid films is determined by the lipid because the surface pressure of the mixed film is the same as the lipid equilibrium spreading pressure, and the monolayer is not saturated by BSA. However, the surface activity of mixed BSA‐lipid films is determined by BSA as the monolayer is saturated by the protein.
Surface tension of bovine serum albumin and tween 20 at the air‐aqueous interface
Authors: NiɁo Ma Rosario Rodríguez , Patino J. M. Rodríguez
Published: May 2007

Interfacial properties (surface tension, σ, and critical micelle concentration, CMC) of aqueous solutions of Tween 20 (polyoxyethylene sorbitan monolaurate) and/or bovine serum albumin (BSA) were evaluated. Temperature, Tween 20 concentration in the aqueous phase, BSA/Tween 20 ratio, and aqueous phase composition [water, ethanol (0.5, 1.0, and 2.5 M), and sucrose (0.5 M)] were the variables studied. The CMC of Tween 20 was determined by surface tension measurements (Wilhelmy plate method). The existence of BSA‐Tween 20 interactions was deduced from surface tension measurements. The results show that the effect of temperature on CMC depends on the aqueous phase composition, but the σ value at CMC, σCMC, does decrease as temperature is increased. The CMC and σCMC values also depend on the aqueous phase composition. In aqueous ethanol solutions, the CMC increases, but σCMC decreases. However, in sucrose aqueous solutions, the CMC decreases, but there is no significant effect on σCMC. The BSA‐Tween 20 interactions at the interface depend on both Tween 20 concentration (C) and solute in the bulk phase. In water and aqueous solutions of ethanol and sucrose, σ values decrease in the presence of protein at CCMC. This is an indication that the interfacial characteristics of the mixed film are determined by either the protein or the lipid at the higher and lower protein/lipid ratio, respectively. In the intermediate region, the existence of BSA‐Tween 20 interactions dominates the interfacial characteristics of mixed films.
The influence of chemical interesterification on physicochemical properties of complex fat systems 1. Melting and crystallization
Authors: Marangoni Alejandro G. , Rousseau Dérick
Published: May 2007

The effects of blending palm oil (PO) with soybean oil (SBO) and lard with canola oil, and subsequent chemical interesterification (CIE), on their melting and crystallization behavior were investigated. Lard underwent larger CIE‐induced changes in triacylglycerol (TAG) composition than palm oil. Within 30 min to 1 h of CIE, changes in TAG profile appeared complete for both lard and PO. PO had a solid fat content (SFC) of ∼68% at 0°C, which diminished by ∼30% between 10 and 20°C. Dilution with SBO gradually lowered the initial SFC. CIE linearized the melting profile of all palm oil‐soybean oil (POSBO) blends between 5 and 40°C. Lard SFC followed an entirely different trend. The melting behavior of lard and lard‐canola oil (LCO) blends in the 0–40°C range was linear. CIE led to more abrupt melting for all LCO blends. Both systems displayed monotectic behavior. CIE increased the DP of POSBO blends with ≥80% PO in the blend and lowered that of blends with ≤70% PO. All CIE LCO blends had a slightly lower DP vis‐à‐vis their noninteresterified counterparts.
Isothermal crystallization of hydrogenated sunflower oil: I—Nucleation
Authors: Herrera M. L. , Falabella C. , Melgarejo M. , AɁón M. C.
Published: May 2007

Nucleation kinetics of sunflower seed oil, which was hydrogenated under two different conditions, was studied by means of a polarized light microscope and an optical setup with a laser as the light source. When the laser was used, observed induction times were shorter than the ones measured by the microscope. The laser method was found to be more sensitive and accurate. Two different crystallization behaviors were found depending on the chemical composition of the samples. Samples with high content of trielaidin crystallized in the β form at temperatures close to the melting points. They exhibited both β′ and β forms depending on crystallization temperature, as happens in natural semisolid fats such as palm oil. Samples with high content of mixed oleic and elaidic triacylglycerols crystallized in the β′ form even at temperatures close to the melting points and they did not show β form under the conditions used in this study. Activation free energies of nucleation for hydrogenated sunflower seed oil were low for the two hydrogenation conditions. It can be concluded that nucleation of sunflower seed oil is a fast process and initially needs low supercooling. These results are also important from a practical point of view for processing design, especially in regards to processes in which fats should be completely crystallized by the end of the production line.
Determination of phospholipids in vegetable oil by fourier transform infrared spectroscopy
Authors: Nzai J. M. , Proctor A.
Published: May 2007

A method was developed to determine the total phospholipid content in vegetable oil by Fourier transform infrared spectroscopy (FTIR). Calibration curves of I‐α‐phosphatidylcholine (PC), I‐α‐phosphatidylethanolamine (PE), and I‐α‐phosphatidylinositol (PI) in hexane were generated at different concentrations. The optimal phospholipid absorption bands between 1200–970 cm−1 were identified and used for quantitative determination. High R2≥0.968 were observed between band areas and phospholipid standard concentrations. Phospholipids from crude soybean oil were obtained by water degumming, and purification was performed on a silicic acid column. The phospholipid contents of purified phospholipid extract, degummed and crude soybean oil determined from calibration equations were >90, 0.0113, and 1.77%, respectively. High correlations of determination (R2≥0.933) were observed between the FTIR method and thin‐layer chromatography‐imaging densitometry method for the determination of phospholipid content. FTIR was found to be a useful analytical tool for simple and rapid quantitative determination of phospholipids in vegetable oil.