bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipid analyses of isolated surface membranes ofLeishmania Donovani promastigotes
Authors: Wassef Momtaz K. , Fioretti Thomas B. , Dwyer Dennis M.
Published: November 2006

Constituent lipids of surface membranes (SM) isolated fromLeishmania donovani promastigotes were analyzed and compared with those obtained from whole cells and an isolated kinetoplast‐mitochondrion fraction (KM). On a dry weight basis, the total extractable lipids constituted ≈47%, 12% and 24% of the SM, cells and KM, respectively. The total lipids of SM, cells and KM all were composed of ≈70% phospholipids (PL), 20–25% neutral lipids and 5–10% glycolipids. Sterols and diglycerides composed 60% and 30%, respectively, of the various neutral lipid fractions. Several mannose‐ and galactose‐containing glycolipids were fractionated but not identified. The glycolipid fractions from cells and SM had demonstrable antigenic activities with rabbit anti‐SM sera. Striking quantitative differences were apparent between the PL profiles of the 3 cellular components examined. The PL of SM, whole cells and KM, respectively, were composed of: 15%, 51% and 24% phosphatidylcholine; 37%, 13% and 11% phosphatidylethanolamine (PE); 18%, 10% and 14% phosphatidylinositol; 10%, 1% and 4% phosphatidylserine and traces of cardiolipin, phosphatidylglycerol and phosphatidic acid. An unknown PL containing sphingosine, choline and vicinal hydroxyl groups but no free amino moieties made up ≈19% of the PL of SM and whole cells, but it constituted ≈27% of the PL of KM. The PL side chain constituents of whole cells and SM were composed mainly of longchain fatty acids (C18–20). Further, over 50% of the PE of SM was in the alkyl and alK‐1‐enyl ether forms. These SM properties might contribute to the organism's resistance to digestion in the hydrolytic environs of both its insect vector and mammalian hosts.
Decrease in alkaline triglyceride lipase in primary cultured hepatocytes from mice with sarcoma 180
Authors: Masuno Hiroshi , Okuda Hiromichi
Published: November 2006

Primary cultured hepatocytes from normal mice and mice with Sarcoma 180 were characterized. The viability of freshly isolated heptocytes from both sources was over 90% and the cells had a relatively stable population of DNA for a minimum of three days. After incubation with (3H)leucine, the syntheses and secretions of (3H)labeled trichloracetic acid‐insoluble materials by hepatocytes from both normal and tumor‐bearing mice increased similarly. However, the alkaline triglyceride lipase activity of a homogenate of freshly isolated hepatocytes from tumor‐bearing mice was one‐third that of cells from normal mice. the activity of hepatocytes from tumor‐bearing mice inceeased less during culture than did the activity of cells isolated from normal mice.
Polyphosphoinositides and the shape of mammalian erythrocytes
Authors: Quist Eugene , Powell Patricia
Published: November 2006

The relationship between polyphosphoinositide and phosphatidic acid (PA) metabolism and Mg‐ATP dependent shape and viscosity changes in erythrocyte ghosts from four mammalian species was examined. Ghosts prepared from rabbit, dog, human and guinea pig erythrocytes were transformed from echinocytes to discocytes within 15 min in the presence of 1 mM Mg‐ATP at 25 C. In all species these Mg‐ATP shape transformations were associated with a 30–45% decrease in the specific viscosity of the ghost suspensions. Mg‐ATP induced a second transformation of discocytic ghosts to cup shape forms without a further decrease in viscosity. A considerable species variation in the rates of Mg‐ATP dependent viscosity and shape changes and incorporation of32P into phosphatidylinositol‐4′ phosphate (PIP), phosphatidylinositol‐4′5′bisphosphate (PIP2) and especially PA form MG‐[γ32P]‐ATP in ghosts was found. However, the rates of Mg‐ATP dependent synthesis of PIP and PIP2 and shape and viscosity changes in each species were of the same magnitude. Ca2+ or neomycin strongly inhibited PIP labeling and Mg‐ATP shape and viscosity changes in ghosts of the different species. Ca2+ or neomycin usually increased or had little effect on32P incorporation into PA and PIP2. The possibility that Mg‐ATP‐induced changes in erythrocyte membrane shape and deformability are dependent on increases in membrane PIP and PIP2 is discussed.
Chromogenic determination of lipid hydroperoxides by sesamol dimer
Authors: Kikugawa Kiyomi , Nakahara Takami , Taniguchi Yasumichi , Tanaka Masami
Published: November 2006

A specific chromogenic assay for lipid hydroperoxides was established. The principle of the assay was based on the reaction of sesamol dimer and lipid hydroperoxides in the presence of hemoglobin (methemoglobin, oxyhemoglobin or carbonmonoxyhemoglobin) which produced violet‐colored quinone or semiquinone dimer (IḬ) having an absorption maximum at 550 nm (SD method). By this method, 0.1 μmol methyl linoleate hydroperoxide could be determined with higher sensitivity than the conventional peroxide value (POV) method. This method requires 0.2–5 mg of the sample for determination of lipid hydroperoxides. The extent of oxidation of oleic acid, linoleic acid, methyl oleate, methyl linoleate, soybean oil, sesame oil, hog fat, beef fat, chicken fat and the fat‐fraction of processed foods could be determined, although the sensitivity varied with the samples and with the degree of autoxidation.
Intestinal cholesterol uptake: Comparison between mixed micelles containing lecithin or lysolecithin
Authors: Reynier M. O. , Lafont H. , Crotte C. , Sauve P. , Gerolami A.
Published: November 2006

The aim of our study was to define the mechanism by which cholesterol uptake is inhibited by lecithin but not by lysolecithin. The work compared the cholesterol uptake by everted rat jejunal sacs from bile salt‐lecithin‐cholesterol or bile salt‐lysolecithin‐cholesterol micelles. The micellar size and the cholesterol saturation were measured.

The size or molecular weight increases when the lecithin concentration rises, and the cholesterol uptake decreases and leads to zero when the micelles contain more than 30% lecithin. The size of bile salt‐lysolecithin‐cholesterol micelles is smaller than that of lecithin micelles in comparable molar ratios. Consistent with this result is the fact that, for a given phospholipid concentration, cholesterol uptake is greater in the presence of lysolecithin than in the presence of lecithin. The diffusion rate of the micelles through the unstirred water, layer decreases when micellar size increases. However, the comparison of uptakes from lecithin or lysolecithin micelles similar in size and in cholesterol saturation showed that the cholesterol uptake is still lower for lecithin micelles. This shows that with larger micelles some factor other than micellar size and cholesterol content of the micelles is important. We observe that lysolecithin absorption is 15‐fold greater, than lecithin absorption. We suggest that lysolecithin absorption results in a rapid supersaturation with cholesterol leading to cholesterol absorption.
The effect of penicillin on fatty acid synthesis and excretion inStreptococcus mutans BHT
Authors: Brissette Janice L. , Pieringer Ronald A.
Published: November 2006

Treatment of exponentially growing cultures ofStreptococcus mutans BHT with growth‐inhibitory concentrations (0.2 μg/ml) of benzylpenicillin stimulates the incorporation of [2‐14C] acetate into lipids excreted by the cells by as much as 69‐fold, but does not change the amount of14C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. The increase in the radioactive content of the extracellular lipids reflects an actual net increase in the total fatty acid content as determined by a chemical assay. During a 4‐hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration (per mg cell dry weight) increases 1.5 fold, even though there is no growth or cellular lysis. No change is observed in the intracellular fatty acid ester content.

An indication of the relative rate of fatty acid synthesis was most readily obtained by placingS. mutans BHT in a buffer containing14C‐acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of [14C]‐acetate into fatty acids. However, if cells are exposed to penicillin in a growth‐supporting medium and then are transferred to the nongrowing buffer system containing no penicillin, the previously exposed cells retain the ability to incorporate [14C]‐acetate into fatty acid at a higher rate than untreated cells over a prolonged period of time. The stimulation of [14C]‐acetate into fatty acids in this system parallels but is not dependent on the stimulation by penicillin of the incorporation of [14C]‐glycerol into glycerolipid and lipoteichoic acid synthesis previously demonstrated by our laboratory.
Adipocyte fatty acid mobilization in vivo: Effects of age and anatomical location
Authors: Hartman Arthur D.
Published: November 2006

The objectives of the present study were to determine if adipocyte trigly ceride fatty acid (TGFA) mobilization in vivo varied among the different adipose tissue depots and whether these rates were affected by age. In order to accomplish these objectives, two groups of rats were studied. The first group initially weighed 84±1 and the second group 333±2. Both groups were placed on a semisynthetic diet containing 6% corn oil (w/w) and 14% triundecanoin (w/w) for a period of 4 wk. Triundecanoin contains an 11‐carbon (C‐11) fatty acid (undecanoic acid) that was used to label the adipocyte TGFA. At the end of the 4‐wk feeding period, triundecanoin was removed from the diet and replaced with an equivalent amount of corn oil. At this time and at weekly intervals for the next 4 wk, 5 rats from each age group were killed for the determination of TGFA composition in isolated dipocytes from the epididymal (Epi), perirenal (PR), subcutaneous (SC) and mesenteric (M) adipose tissue depots. When the content of C‐11 was expressed as mole percent of the total fatty acids, mobilization was significantly more rapid from the PR and M depots than in the other two depots in the young rats. In the older rats mobilization was significantly slower in all depots compared to the younger group. The rates of mobilization were not different between the depots in the older animals. Since fat cell size continued to increase throughout the duration of the study, part of the decrease in C‐11 content can be accounted for by dilution by newly acquired TGFA. When data were compared on the basis of the actual pmoles of C‐11 per cell, rates of mobilization were not different between the depots nor was mobilization affected by age. These results emphasize again the impact the manner in which adipocyte metabolic data are expressed has on interpretation(s) when comparing adipocytes of different depots or from rats of different age.
Activities of liver mixed function oxidase system in rats fedtrans fat
Authors: Nishiyama Kikuko , Ide Takashi , Sugano Michihiro
Published: November 2006

Rats were fed diets containing either camellia oil or partially hydrogenated corn oil, as a source ofcis ortrans octadecenoate, respectively, in the presence of adequate linoleic acid. After 35 days of feeding the diets, activities of several hepatic drug metabolizing enzymes as well as the content of hepatic microsomal cytochrome P‐450 were determined. Geometrical difference in the dietary fat did not affect the amount of microsomal protein nor the content of cytochrome P‐450. Also, activities of NADPH cytochrome C reductase, aminopyrine N‐demethylase and biphenyl hydroxylase were approximately the same between two groups of rats. Aniline hydroxylase was slightly elevated in the rats fedtrans fat. It was concluded that the difference in the geometry of dietary fatty acids had little effect in modulating the hepatic mixed function oxidase system.
Lipids and lipid antioxidant systems in developing eggs of salmon (Salmo salar)
Authors: Cowey C. B. , Bell J. G. , Knox D. , Fraser A. , Youngson A.
Published: November 2006

Lipid class and fatty acid analyses were carried out on developing salmon eggs at four clearly defined pre‐feeding stages, namely, fertilization, eyed egg stage (50 days), hatching (yolk sac fry, 98 days) and swim up fry (138 days).

Measurements of components of the system considered to be involved in defense of cells against lipid peroxidation (glutathione peroxidase, EC 1.11.1.9, glutathione S‐transferase, EC 2.5.1.18, reduced glutathione [GSH], α‐tocopherol and ascorbic acid) were made at the same time. Levels of triacylglycerol decreased markedly during development, but there were few changes in fatty acid composition, indicating a non‐selective utilization of fatty acids. Phosphatidylcholine was the dominant polar lipid (>94% by weight) in fertilized eggs. It was used preferentially during development so that in swim up fry the ratio phosphatidylcholine: phosphatidylethanolamine approached that found in fish muscle. Amounts of docosahexaenoic acid and arachidonic acid in polar lipids were significantly greater (p<0.01) in swim up fry than in fertilized eggs.

Activities of the two enzymes were very low in the fertilized egg and remained low until hatching, when there was a concerted increase in their activity and in the concentration of GSH. Egg tocopherol concentrations decreased significantly during development, but whole body concentrations in swim up fry were not dissimilar from those in normal juvenile fish. Ascorbic acid, on the other hand, declined to very low levels in swim up fry; the restoration of this vitamin during first feeding seems vital to the well being of the fish.
Characterization of gangliosides of porcine erythrocyte membranes: Occurrence of ganglioside GD3 as major ganglioside
Authors: Suzuki Yasuo , Suzuki Naoto , Michi Hiroyasu , Matsumoto Makoto
Published: November 2006

Four major ganglioside species were isolated from porcine erythrocyte membranes by DEAE‐Sephadex and Iatrobeads column chromatography. Treatment of the lipids with graded neuraminidase and β‐galactosidase, gas chromatographic analysis of their carboyhydrates, sphingosine bases and molecular species of sialic acid revealed that the structure of these gangliosides were GM3(NeuAc), GM3(NeuGc), GD3(NeuAc) and GD3(NeuGc), each of which was 16±2 μg, 304±42 μg, 30±3 μg and 240±26 μg, respectively, per gram of the dry erythrocyte stroma. The amount of GM3 and GD3 accounted for more than 95% of total gangliosides of the erythrocytes. Porcine erythrocytes may provide a good source for large scale preparation of ganglioside GD3 which recently was identified as a human melanoma‐associated antigen.
The effect of fatty acid chain length and unsaturation on the chromatographic behavior of triglycerides on latroscan chromarods
Authors: Kramer J. K. G. , Fouchard R. C. , Farnworth E. R.
Published: November 2006

The chromatographic behavior of lipid classes on Chromarods with common developing solvents used for the Iatroscan system was influenced by the esterified fatty acids present in the lipid class. The Rf value of the lipid class increased with increasing chain length and increasing unsaturation of the fatty acids; the increase in Rf value per methylene carbon was about twice that per double bond. The effect was evident in both triglycerides and phosphatidylcholines. This partial separation of molecular species within a lipid class caused widening of the lipid class band on the Chromarods and can result in poorer resolution, particularly in biological samples.
Lipid peroxidation and oxidation of several compounds by H2O2 activated metmyoglobin
Authors: Kanner Joseph , Harel Stella
Published: November 2006

Activated metmyoglobin (MetMb) by H2O2 initiates oxidation of microsomal unsaturated fatty acids, β‐carotene and methional but not formate. Lipid peroxidation by activated MetMb was not inhibited by catalase. The activated species which initiaes lipid peroxidation appears to be a porphyrin cation radical, P∸+FeIV=O, and not a hydroxyl radical.
Unusual predominance of even‐carbon hydrocarbons in an antarctic food chain
Authors: Nachman Ronald J.
Published: November 2006

A comparative study of lipids was conducted inEuphausia crystallorophias, Pleuragramma antarcticum andDissostichus mawsoni, representing three trophic levels of an Antarctic food chain. Very large concentrations of triglycerides were found inP. antarcticum andD. mawsoni, but the nature of the free fatty acids and triglyceride fatty acid distributions of all three species was unremarkable. The larger amounts of free fatty acids obtained inEuphausia crystallorophias, when compared to a previous analysis, may have been due to enzymatic hydrolyses of lipid esters during cold storage. In contrast, the hydrocarbon distributions in the three organisms were found to contain an unusual predominance of even‐carbonn‐alkane constituents. A different biochemical pathway to hydrocarbons may be operating in members of this food chain that is so well adapted to the low temperatures of Antarctic waters.
The effects of ethanol content and emulsifying agent concentration on the stability of vegetable oil‐ethanol emulsions
Authors: Xu Qingyi , Nakajima Mitsutoshi , Nabetani Hiroshi , Iwamoto Satoshi , Liu Xinqi
Published: November 2006

In vegetable oil‐ethanol emulsions ethanol is the polar phase and vegetable oil is the nonpolar phase. The primary advantage of vegetable oil‐ethanol emulsions over conventional water‐oil emulsions is that they enable the incorporation of water‐and oil‐insoluble or poorly soluble functional compounds and/or drugs into emulsions. A number of nonionic surfactants were used to select appropriate stabilizers for stable vegetable oil‐ethanol emulsions. We found decaglycerol mono‐oleate (MO750) to be the best stabilizer for ethanol‐in‐oil (E/O) emulsions. The effects of ethanol content and of emulsifying agent concentration on the stability of vegetable oil‐ethanol emulsions were examined with MO750. After emulsification, two turbid layers formed simultaneously when ethanol content exceeded 20 wt%. The top layers (oil‐in‐ethanol emulsions; O/E emulsions) were very unstable, whereas the stability of the bottom layers (E/O emulsions) depended on the ethanol content. The stability of E/O emulsions is closely related to the effective concentration of MO750 aggregates, which play an important role in the film thickness stability of interfacial films formed by surfactant aggregates. Instability of E/O emulsion at 5 wt% MO750 is probably due to the polydispersity (i.e., nonuniform size and shape) of MO750 aggregates at high MO750 concentration. E/O emulsions prepared with 0.1, 0.5, and 1 wt% MO750 were stable, suggesting that the interfacial films formed were effective in protecting the droplets against coalescence and Ostwald ripening.
Comparison of lipase‐transesterified blend with some commercial solid frying shortenings in Malaysia
Authors: Chu B. S. , Ghazali H. M. , Lai O. M. , Che Man Y. B. , Yusof S. , Tee S. B. , Yusoff M. S. A.
Published: November 2006

A transesterified experimental solid frying shortening was prepared from a palm stearin/palm kernel olein blend at 1∶1 ratio (by weight) by using Rhizomucor miehei lipase at 60°C for 6 h. The fatty acid (FA) and triacylglycerol compositions, polymorphic forms, melting and cooling characteristics, slip melting point (SMP), and solid fat content (SFC) of the transesterified blend were then compared with five commercial solid frying shortenings (three domestic and two imported) found in Malaysia. All the domestic shortenings contained nonhydrogenated palm oil or palm olein and palm stearin as the hard stock, whereas the imported frying shortenings were formulated from soybean oil and cottonseed oil and contained high level of β′ crystals. Trans FA were also found in these samples. The lipase‐transesterified blend was found to be more β′‐tending than the domestic samples. The SMP of the transesterified blend (47.0°C) fell within the range of the domestic samples (37.8–49.7°C) but was higher than the imported ones (42.3–43.0°C). All samples exhibited similar differential scanning calorimetry cooling profiles, with a narrow peak at the higher temperatures and a broad peak at the lower temperatures, even though their heating thermograms were quite different. Imported samples had flatter SFC curves than both the experimental and domestic samples. The domestic samples were found to have better workability or plasticity at higher temperatures than the imported ones, probably because they were formulated for a tropical climate.
Definition of a model fat for crystallization‐in‐emulsion studies
Authors: Lopez C. , Riaublanc A. , Lesieur P. , Bourgaux C. , Keller G. , Ollivon M.
Published: November 2006

Numerous food products are dispersed in droplet emulsions in which fat is partially crystallized. A model fat allowing the study of crystallization in emulsion, obtained by the mixing of two fats (one solid and one liquid at room temperature) with simple triacylglycerol (TG) composition, is defined and characterized. Cocoa butter (CB), a vegetable fat mainly composed of monounsaturated long‐chain fatty acids (POP, POST, StOSt, where P=palmitic, O=oleic, St=stearic), and miglyol, a synthetic oil made from capric and caprylic fatty acids, were chosen, respectively. The thermal behaviors of CB, miglyol, and their mixtures are studied using high‐sensitivity differential scanning calorimetry (DSC). The CB/miglyol ratio was optimized (i) in order to make stable emulsions as a function of time, (ii) so that the mixture displays several solid phases on cooling that result from CB polymorphism, and (iii) in order to keep, even at low temperature, a liquid moiety facilitating the phase transitions. The CB 75%/miglyol 25% composition is defined as the model mixture. This mixture is characterized on cooling at 0.5°C/min by coupled X‐ray diffraction as a function of temperature and DSC experiments. First and α 2L (49.3 Å) variety is formed. Then, co‐crystallization of both CB and miglyol TG shows the simultaneous formation of longitudinal stackings of 44.5 and 34.5 Å with a lateral organization of β′ form. An unusual TG packing corresponding to compound formation is proposed to explain the observation of a 34.5 Å long‐spacing. The crystallization behavior of the model fat mixture dispersed in emulsion droplets is also monitored in order to validate its use.
Photometric assay for polyphenol oxidase activity in olives, olive pastes, and virgin olive oils
Authors: Valgimigli Luca , Sanjust Enrico , Curreli Nicoletta , Rinaldi Augusto , Pedulli Gian F. , Rescigno Antonio
Published: November 2006

A photometric method is proposed that allows the determination of phenolase activity in olive fruits, olive pastes, and virgin olive oil. The method can also be used to quantify partially purified phenolase from olives, and is based on the coupling between 4‐methyl‐o‐benzoquinone, the reaction product of phenolase toward its substrate 4‐methylcatechol, and the aromatic amine 4‐amino‐N,N‐diethylaniline. The deep‐blue adduct arising from this reaction has been characterized by means of nuclear magnetic resonance and mass spectrometric techniques and identified as 4‐(4′‐diethylaminophenylimino)‐2‐hydroxy‐5‐methyl‐cyclohexa‐2,5‐dienone. This compound shows an absorption band, centered (in dichloromethane) at 617 nm, with an ε of 11,080 M−1cm−1. The main advantage of the proposed method resides in the high absorption coefficient of the adduct and its ultraviolet/visible absorption pattern, with a λmax in a spectral region void of significant interferences by the pigments that ultimately will probably be present in the extracts to be tested by this proposed method. The method has proven to be sensitive, specific, and reliable.
Off‐line coupling of high‐performance liquid chromatography and 1H nuclear magnetic resonance for the identification of filbertone in hazelnut oil
Authors: Ruiz del Castillo M. L. , Herraiz M. , Molero M. D. , Herrera A.
Published: November 2006

A new procedure is presented for off‐line coupling of high‐performance liquid chromatography and proton nuclear magnetic resonance spectroscopy (1H NMR) in hazelnut oil analysis. The optimization of some parameters affecting both the liquid chromatography preseparation step and the effective multiple‐solvent suppression required for the NMR study enabled us to determine the presence in a hazelnut oil of (E)‐5‐methyl‐hept‐2‐en‐4‐one (filbertone), a marker previously proposed to detect the adulteration of olive oil with hazelnut oil. The described procedure requires the filtration of the oil prior to its introduction into the chromatographic system and combines the advantages of providing sufficient sensitivity and selectivity with simple methodology and reduced sample handling.
Free fatty acid formation and lipid oxidation on milled rice
Authors: Lam Henry S. , Proctor Andrew , Meullenet Jean‐François
Published: November 2006

Milled rice was stored at 37°C and 70% humidity and sampled regularly for 50 d. Rice surface lipid was extracted with isopropanol and analyzed for free fatty acids (FFA) and conjugated diene (CD) contents. Diffuse reflectance Fourier transform infrared (DRIFTS) spectra of the rice samples were also obtained. FFA and CD levels increased together during rice storage and exhibited three distinct phases. DRIFTS identified a decrease in intensity at 1746 cm−1 (ester, −C=O) and increases in intensity at 1731 cm−1 (aldehyde, −CO) and 1714 cm−1 (fatty acid, −C=O) during storage, which correlated well with the chemical analysis data. DRIFTS spectral data were analyzed by a partial least squares regression method to identify spectral regions that correlate strongly with measured FFA and construct prediction models. Overall, the mid‐infrared region (4000–400 cm1) gave the best model (R=0.98, root mean square error of cross‐validation=0.05) and also predcted the FFA content of milled rice well. The DRIFTS technique has potential for use in studying qualitative chemical changes on the milled rice surface lipids and for predicting FFA on milled rice.
Hepatic lipid characteristics and histopathology of laying hens fed CLA or n−3 fatty acids
Authors: Cherian Gita , Goeger Mary P.
Published: November 2006

The effect of dietary CLA and n−3 PUFA on hepatic TAG accumulation, histopathology, and FA incorporation in lipid classes by laying chickens was investigated. One hundred twenty 30‐wk‐old single‐comb white leghorn laying hens were distributed randomly to four treatments (3 replications of 10 birds) and were fed diets containing CLA and animal fat (Diet I), 18∶3n−3 (Diet II), or long‐chain n−3 FA (Diet III). A sunflower oil (n−6 FA)‐based diet was the control. Feeding Diet I resulted in an increase in hepatic total lipids (P<0.05). The liver TAG content was 32.2, 18.9, 29.4, and 18.7 mg/g for hens fed Diet I, Diet II, Diet III, and the control diet, respectively (P<0.05). The serum TAG was lowest in bilds fed Diet II (P<0.05). Diet I resulted in an increase in the total number of fat vacuoles and lipid infiltration in hepatocytes (P<0.05). The number of cells with 75% or higher lipid vacuolation was observed only in birds fed Diet I. Feeding diets containing CLA resulted in an increase in the content of the c9,t11 CLA isomer in liver TAG and PC (P<0.05). No difference was observed in the CLA concentration of hepatic PE fractions. The content of DHA (22∶6n−3) was higher in the TAG, PC, and PE of hens fed Diet II and Diet III than Diet I and the control (P<0.05). Feeding CLA resulted in an increase in total saturated FA in the TAG and PC fractions (P<0.05). Long‐term feeding of CLA in laying birds leads to an increase in liver TAG and may predispose birds to fatty liver hemorrhagic syndrome.
Alterations of fatty acid metabolism and membrane fluidity in peroxisome‐defective mutant ZP102 cells
Authors: Nagura Michiaki , Saito Makiko , Iwamori Masao , Sakakihara Yoichi , Igarashi Takashi
Published: November 2006

We investigated lipid composition and FA metabolism in Chinese hamster ovary (CHO‐K1) cells and Pex5‐mutated CHO‐K1 (ZP102) cells to clarify the biochemical bases of peroxisome biogenesis disorders (PBD). ZP102 cells have defective peroxisomes and exhibit impairments of peroxisomal β‐oxidation of FA and plasmalogen biosynthesis. In addition, we identified FA metabolic alterations in the synthesis of several classes of lipids in ZP102 cells. The concentration of FFA in ZP102 cells was twice that in CHO‐K1 cells, but methyl esters and TAG were decreased in ZP102 cells in comparison with control cells. Also, ceramide monohexoside (CMH) concentration with ZP102 cells was significantly increased compared with the control cells. The FA molecular species, particularly the saturated to unsaturated ratios, of individual lipids also differed between the two cell types. The rate of incorporation of [14C]‐labeled saturated acids into sphingomyelin (SM) and CMH in ZP102 cells was lugher than that in CHO‐K1 cells. Lignoceric acid incorporated into cells was predominantly utilized for the synthesis of SM at 24 h after removal of [14C] lignoceric acid from the culture medium. ZP102 cells showed higher fluorescence anisotropy of 1,3,5‐diphenylhexatriene, corresponding to lower membrane mobility than in CHO‐K1 cells. In particular, alteration of lipid metabolism by a Pex5 mutation enhanced metabolism of saturated FA and sphingolipids. This may be related to the reduced membrane fluidity of ZP102 cells, which has been implicated in the dysfunction of membrane‐linked processes in PBD.
Fatty acids of serine, ethanolamine, and choline plasmalogens in some marine bivalves
Authors: Kraffe Edouard , Soudant Philippe , Marty Yanic
Published: November 2006

The FA composition of glycerophospholipid (GPL) classes and subclasses was investigated in whole animals of three marine bivalve mollusks: the Japanese oyster Crassostrea gigas, the blue mussel Mytilus edulis, and the Manila clam Ruditapes philippinarum. Individual organs (gills, mantle, foot, siphon, and muscle) of the Manila clam also were examined. The PS plasmalogen (PSplsm), PE plasmalogen (PEplsm), and PC plasmalogen (PCplsm) subclasses were isolated by HPLC, and their individual FA compositions were examined using GC. Plasmalogen forms of PS and PE, when compared to their respective diacyl forms, were found to be specifically enriched with non‐methylene‐interrupted (NMI) FA (7,15–22∶2, 7, 13–22∶2, and their precursors) and 20∶1n−11 FA. Such a clear specific association was not found for PCplsm. Interestingly, this trend was most apparent in PSplsm, and the above FA were found to be, respectively, the predominant PUFA and monounsaturated FA in the PSplsm isolated from the three species. This specificity was maintained in all the analyzed organs of the Manila clam but varied in proportions: The highest level of plasmalogens, NMI FA, and 20∶1n−11 was measured in gills and the lowest was in muscle. These results represent the first comprehensive report on a FA composition of the PSplsm subclass isolated from mollusks. The fact that NMI FA and 20∶1n−11, which are thought to be biosynthesized FA, were mainly associated with aminophospholipid plasmalogens (PE and PS) is likely to have a functional significance in bivalve membranes.
Steam‐explosion pretreatment of olive cake
Authors: Felizón B. , Fernández‐Bolaños J. , Heredia A. , Guillén R.
Published: November 2006

Olive cake was processed by steam‐explosion under different steam conditions, followed by fractionation to separate the main components. In the water‐soluble fraction, the main compounds were carbohydrates. Glucose represented a significant part of the total monosaccharide content, especially under conditions of mild severity, followed by arabinose, but the solubilization of sugars occurred predominantly in the oligomeric fraction. Mannitol was also found in significant amounts (1.5%), similar to that in the initial material. In the ethyl acetate extract, low molecular weight phenols were identified, the most aboundant being hydroxytyrosol, which is present in the olive pulp. Hydroxytyrosol is abundant and has great antioxidant activity, reaching 149 mg/100 g of dry olive cake. The procedure used in this study obtained all the hydroxytyrosol residual present in the by‐product. The constitutive polymers were quantified in the insoluble fraction, and the sugar composition showed that cellulose was associated with a high proportion of xylans and other polysaccharides rich in arabinose and galactose. This cellulose was nearly amorphous, as it was highly susceptible to hydrolytic enzymes. The extractables in dilute alkali (not true lignins) increased as steaming became more severe; the residual “lignin” in this fraction decreased. Enzymatic hydrolysis of the insoluble fraction using a cellulolytic complex was also studied. The slight increase in the extent of saccharification was not proportional to the high alkaline delignification. However, when the residues were efficiently delignified with chlorite treatment, the susceptibility to enzymatic hydrolysis greatly increased.
Rheological study of dispersions prepared with modified soybean protein isolates
Authors: Puppo M. C. , Sorgentini D. A. , Añón M. C.
Published: November 2006

Structural modifications of modified soy protein isolates (SPI) were distinguished by rheological behavior. SPI were prepared by acidic (pH 2.5) and thermal‐acidic treatment without (pH 1.6) and with neutralization (pH 8.0). Dynamic properties of dispersions were determined through the variation of storage and loss moduli with frequency, and loss tangent behavior was analyzed. Changes in viscoelastic parameters with protein concentration (10–12% wt/vol) and time of heating (15–60 min) were also determined. Flow properties of dispersions were estimated through apparent viscosity and flow and consistency index measurements. Rheological behavior of dispersions was compared with those found by experiment with commercial mayonnaise, mustard, and salad dressing. The analysis of rheological parameters showed that thermally treated isolates formed dispersions with high elastic modulus and consistency index with a structure mainly stabilized by hydrophobic interactions, although no gelation process after cooling was observed. From the rheological point of view, it was deduced that thermally treated isolates could be used as ingredients in the formulation of salad dressings. The alkaline sample would be more versatile because, depending on protein concentration and thermal treatment, the consistency of its dispersions was like that in salad dressing, or similar to those of mustard and mayonnaise.
10(S)‐Hydroxy‐8(E)‐octadecenoic acid, an intermediate in the conversion of oleic acid to 7,10‐dihydroxy‐8(E)‐octadecenoic acid
Authors: Kim Hakryul , Gardner Harold W. , Hou Ching T.
Published: November 2006

The new microbial isolate Pseudomonas aeruginosa (PR3) has been reported to produce from oleic acid a new compound, 7,10‐dihydroxy‐8(E)‐octadecenoic acid (DOD), with 10‐hydroxy‐8‐octadecenoic acid (HOD) being a probable intermediate. The production of DOD involves the introduction of two hydroxyl groups at carbon numbers 7 and 10, and a rearrangement of the double bond from carbons 9–10 to 8–9. It has been shown that the 8–9 unsaturation of HOD was possibly in the cis configuration. Now we report that the rearranged double bond of HOD is trans rather than cis, as determined by spectral data. Also, it was found that the 10‐hydroxyl was in the S‐configuration as determined by gas chromatographic separation of R‐ and S‐isomers after preparation of the (−)‐menthoxycarbonyl derivative of the hydroxyl group followed by oxidative cleavage of the double bond and methyl esterification. This latter result coincides with our recent finding that the main final product, DOD, is in the 7(S),10(S)‐dihydroxy configuration. In addition, a minor isomer of HOD (about 3%) with the 10(R)‐hydroxyl configuration was also detected. From the data obtained herein, we concluded that 10(S)‐hydroxy‐8(E)‐octadecenoic acid is the probable intermediate in the bioconversion of oleic acid to 7(S),10(S)‐dihydroxy‐8(E)‐octadecenoic acid by PR3.
Determination of trans fatty acids and fatty acid profiles in margarines marketed in spain
Authors: Alonso L. , Fraga M. J. , Juárez M.
Published: November 2006

Two gas chromatography (GC) procedures were compared for routine analysis of trans fatty acids (TFA) of vegetable margarines, one direct with a 100‐m high‐polarity column and the other using argentation thin‐layer chromatography and GC. There was no difference (P>0.05) in the total trans 18∶1 percentage of margarines with a medium level of TFA (∼18%) made using either of the procedures. Both methods offer good repeatability for determination of total trans 18∶1 percentage. The recoveries of total trans isomers of 18∶1 were not influenced (P>0.1) by the method used. Fatty acid composition of 12 Spanish margarines was determined by the direct GC method. The total contents of trans isomers of oleic, linoleic, and linolenic acids ranged from 0.15 to 20.21, from 0.24 to 0.99, and from 0 to 0.47%, respectively, and the mean values were 8.18, 0.49, and 0.21%. The mean values for the ratios [cis‐polyunsaturated/(saturated +TFA)] and [(cis‐polyunsaturated + cis‐monounsaturated)/(saturated +TFA)] were 1.25±0.39 and 1.92±0.43, respectively. Taking into account the annual per capita consumption of vegetable margarine, the mean fat content of the margarines (63.5%), and the mean total TFA content (8.87%), the daily per capita consumption of TFA from vegetable margarines by Spaniards was estimated at about 0.2 g/person/d.
Differential scanning calorimetric analysis of edible oils: Comparison of thermal properties and chemical composition
Authors: Tan C. P. , Che Man Y. B.
Published: November 2006

The thermal profiles of 17 edible oil samples from different plant origins were examined by differential scanning calorimetry (DSC). Two other confirmatory analytical techniques, namely gas‐liquid chromatography (GLC) and high‐performance liquid chromatography (HPLC), were used to determine fatty acid (FA) and triacylglycerol (TAG) compositions. The FA and TAG compositions were used to complement the DSC data. Iodine value (IV) analysis was carried out to measure the degree of unsaturation in these oil samples. The DSC melting and crystallization curves of the oil samples are reported. The contrasting DSC thermal curves provide a way of distinguishing among these oil samples. Generally, the oil samples with a high degree of saturation (IV<65) showed DSC melting and crystallization profiles at higher temperature regions than the oil samples with high degree of unsaturation (IV>65). Each thermal curve was used to determine three DSC parameters, namely, onset temperature (To), offset temperature (Tf) and temperature range (difference between To and Tf). Reproducibility of DSC curves was evaluated based on these parameters. Satisfactory reproducibility was achieved for quantitation of these DSC parameters. The results show that To of the crystallization curve and Tf of the melting curve differed significantly (P<0.01) in all oil samples. Our observations strengthen the premise that DSC is an efficient and accurate method for characterizing edible oils.
Effect of Alcalase™ on olive pomace protein extraction
Authors: Vioque J. , Clemente A. , Sánchez‐Vioque R. , Pedroche J. , Millán F.
Published: November 2006

The effect of Alcalase™ treatment on olive pomace protein extraction has been studied. Alcalase improves protein extraction from 5 to 30% of total protein. This improvement is not accompained by an increase in degree of protein hydrolysis, probably because protease activity is inhibited by secondary metabolites and the substrate is highly denatured and resistant to hydrolysis. The increase in protein extraction is attributed to fiber solubilization as a result of secondary activities of Alcalase. Protein extracts with a high content of soluble fiber have improved functional properties, with respect to olive pomace, such as water and oil absorption. Emulsifying and foaming activities were inappreciable. The products obtained represent a suitable source of soluble fiber and protein and may contribute to the improvement of the economic status of olive pomace by‐product.
Isolation and separation of tocopherols from olive by‐products with supercritical fluids
Authors: Ibáñez E. , Palacios J. , Señoráns F. J. , Santa‐María G. , Tabera J. , Reglero G.
Published: November 2006

Supercritical fluid extraction of olive pomace, the semisolid residue obtained using two‐phase olive oil production systems, and supercritical fluid chromatographic separation of the extracts were performed to study the content of tocopherols, a group of compounds of interest for the food industry owing to their antioxidant activity. The developed method consists of supercritical CO2 extraction at pilot plant scale and subsequent fractionation by two successive depressurizations. Enrichment of α‐, β‐, and γ‐tocopherol was achieved in separator 2 when working at low densities in the first separator. Fractions obtained using high densities in separator 1 contained major proportions of triglycerides, waxes, and sterols. Tocopherols from olive by‐products were separated and quantified in an environmentally friendly way by using supercritical fluid chromatography with packed capillary columns coated with polyethylene glycol and neat CO2 according to a method previously optimized in our laboratory. The studied olive by‐products can be considered a natural source of antioxidants because substantial concentration of tocopherols have been obtained in the extracts. The isolation and separation of tocopherols from olive pomace by applying supercritical fluid technology provides an interesting approach to exploit such by‐products in an environmentally friendly way.
The effect of the refining process on the interfacial properties of palm oil
Authors: Ho C. C. , Chow M. C.
Published: November 2006

The interfacial tension of palm oil against water at 60°C was determined in the presence of monoglycerides with (i) different acyl chain lengths, (ii) the same acyl chain length but with different unsaturation, and (iii) different phospholipids. The interfacial tensions of the oil/water interface were depressed, albeit to different extents, by the presence of these substances, depending on the acyl chain length, unsaturation, and the chemical structure of the species adsorbed. The adsorption of the saturated monoglycerides C12∶0, C14∶0, C16∶0, C18∶0 and the unsaturated monoglycerides of C18∶1 and C18∶3 is consistent with a Langmuir isotherm at the palm oil/water interface. However, fitting of the data for C18∶2, l‐α‐phosphatidylcholine, and lysophosphatidylcholine to the Langmuir isotherm is less satisfactory. The surface areas of the materials adsorbed at the palm oil/water interface are much larger than those of liquid condensed films and closer to those for liquid expanded films. The influence of the nature of the oil (triglycerides), the minor components in the oil, and thier interactions with the added lipids at the oil/water interface are briefly discussed. The effect of the refining process on the interfacial properties of palm oil against water was also studied. The efficiency of the refining process in minor oil contaminants’ removal and the quality of the oil obtained as reflected by the interfacial properties of the oil is discussed.
Urea‐based fractionation of seed oil samples containing fatty acids and acylglycerols of polyunsaturated and hydroxy fatty acids
Authors: Hayes Douglas G. , Van Alstine James M. , Setterwall Fredrik
Published: November 2006

The selectivity and efficiency of urea complex (UC) formation‐based fractionation of free fatty acids (FFA) were examined. A rapid, simple, and inexpensive procedure recently developed for urea fractionation was applied to lipid mixtures containing various polyunsaturated and hydroxy FFA species. Urea treatment proved useful for isolating polyunsaturated FFA (PUFA) from FFA derived from fish, borage, and linseed oils by removal of saturated and monounsaturated FFA, but was not effective for isolating hydroxy FFA from the FFA derived from castor, Lesquerella, and Dimorphotheca oils. In situations where FFA within the crystalline or UC phase were rich in PUFA, the urea/FFA mole ratio of the UC was relatively higher, with lower recovery of FFA in this phase. The distribution of urea between the crystalline phase and the solvent was not significantly affected by the FFA composition of feed nor the overall ratio of FFA to urea. It was strongly dependent on the overall mass fraction of solvent. Phospholipids and mono‐, di‐, and triacylglycerols were poor templates for UC formation relative to FFA. Their inclusion in acylglycerol mixtures containing FFA reduced UC formation.
Determination of oxidative stability of lipids in solid samples
Authors: Tian Kang , Dasgupta Purnendu K. , Shermer William D.
Published: November 2006

A gas‐phase flow injection analysis (FIA) method for the direct determination of the oxidative stability of solid fat/oil samples is described. Samples are confined with a low level of oxygen in a reactor of adjustable temperature. The oxygen consumption by the sample is automatically monitored after a preset period. The temperature‐dependent data exhibit Arrhenius behavior. Normally, it is difficult to directly determine the stability at ambient temperatures because of inordinately long time requirements. The close correspondence to Arrhenius behavior makes it possible to use the results obtained at higher temperature to calculate the stability of samples at lower temperature conditions, such as at ambient storage temperature. The effects of sample size, sample particle size, sample fat content and the reproducibility of the method over time were studied using synthetic and bone meal samples. The oxygen consumption was found to be linearly dependent on the amount of sample taken, inversely dependent on the particle diameter, and independent of the exact lipid content, given some minimum lipid content. The results exhibited high day‐to‐day reproducibility. The gasphase FIA system developed in this work is easy to operate. Compared with the currently used method, the sample throughput rate is much faster (2–3h for complete multitemperature characterization of a sample) and the sample requirement is much lower (∼1 g). Furthermore, it eliminates the need to extract and recover the fat from the sample for further processing as is required by the other methods commonly used to measure oxidative stability.
Fatty acid derivatives as corrosion inhibitors for mild steel and oil‐well tubular steel in 15% boiling hydrochloric acid
Authors: Quaraishi M. A. , Jamal Danish , Tariq Saeed Mohd
Published: November 2006

Selected hydrazides and thiosemicarbazides of fatty acids with 11, 12, and 18 carbon atoms were synthesized and evaluated as corrosion inhibitors on mild steel and oil‐well steel (N‐80) in boiling 15% hydrochloric acid solution, by weight loss method. Potentiodynamic polarization studies carried out on mild steel and N‐80 steel at room temperature showed that all the tested compounds are of mixed type. Adsorption studies showed that all the investigated compounds followed Temkin's adsorption isotherm.