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PubMed2005

Biodiesel production from triolein and short chain alcohols through biocatalysis.

Oleic acid alkyl esters (biodiesel) were synthesised by biocatalysis in solvent-free conditions. Different commercial immobilised lipases, namely Candida antarctica B, Rizhomucor miehei, and Pseudomonas cepacia, were tested towards the reaction between triolein and butanol to produce butyl oleate. Pseudomonas cepacia lipase resulted to be the most active enzyme reaching 100% of conversion after 6h. Different operative conditions such as reaction temperature, water activity, and reagent stoichiometric ratio were investigated and optimised. These conditions were then used to investigate the effect of linear and branched short chain alcohols. Methanol and 2-butanol were the worst alcohols: the former, probably, due to its low miscibility with the oil and the latter because secondary alcohols usually are less reactive than primary alcohols. Conversely, linear and branched primary alcohols with short alkyl chains (C(2)--C(4)) showed high reaction rate and conversion. A mixture of linear and branched short chain alcohols that mimics the residual of ethanol distillation (fusel oil) was successfully used for oleic acid ester synthesis. These compounds are important in biodiesel mixtures since they improve low temperature properties.

Alcohols↗
PubMed2006

Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent.

In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction.

Adsorption↗
PubMed1993

Eutectic mixed monolayers in equilibrium with phospholipid-bilayers and triolein-liquid phase.

Triolein (TO) and phospholipids (egg yolk phosphatidylcholine, egg yolk phosphatidylethanolamine, and bovine brain phosphatidylserine) had low mutual solubilities and separated into the TO-liquid phase and phospholipid-bilayers. Spreading pressures of the TO-phospholipid mixture (i.e., surface pressures of the mixed monolayer in equilibrium with the phase-separating lipid mixture) at the air/saline interface were independent of the lipid composition. On the other hand, collapse pressures of the mixed monolayer of TO and phospholipid (i.e., surface pressures of the mixed monolayer in equilibrium with the TO-liquid phase) at the interface changed with the monolayer composition and were lower than the spreading pressure. The experimental data indicated the spreading and collapse pressures as offering a phase diagram for the presence of equilibrium between the mixed monolayer, the phospholipid-bilayers and the TO-liquid phase. The diagram showed that TO and the phospholipids were miscible in the mixed monolayer, forming an eutectic mixed monolayer. When the mixed monolayer initially had the eutectic composition, no collapse of the monolayer was detected until the surface pressure reached the value of the spreading pressure. No specific complex between TO and the phospholipid is required to explain the stability and collapse of the mixed monolayers. The bulk immiscibility of the lipids elucidated by the spreading pressure-measurements, immediately leads to the phase behaviors observed.

Animals↗
PubMed1998

Cutinase binding and activity at the triolein-water interface monitored by oil drop tensiometry.

Changes of the oil-water interfacial tension resulting from binding of Fusarium solani pisi cutinase and subsequent lipid hydrolysis were investigated using the oil drop technique. An ELISA was developed to determine the amount of cutinase bound to the triolein-water interface after biotinylation of the enzyme. Cutinase irreversibly adsorbs to a maximum value of about 2 mg/m2. A minimal specific activity of 110 mumol/min/mg was calculated for cutinase acting on a single oil droplet, which is close to the activity found for triglyceride emulsions. At a maximum surface load cutinase could generate one monolayer of fatty acid products per second at the interface. It was found that oleic acid rapidly dissolves into the oil phase under the conditions used. The interfacial tension measured reflects the adsorption of cutinase to the oil droplet and also responds to the fate of the hydrolysis products. A model is presented that describes the catalytic events at the oil-water interface during lipid hydrolysis.

Adsorption↗
PubMed2002

Review of the background and application of triolein-containing semipermeable membrane devices in aquatic environmental study.

This paper briefly reviews research on passive in situ samplers for aquatic environments but focuses on the development and application of the triolein-containing semipermeable membrane device in aquatic environmental monitoring. Special attention is paid to the calibration of the devices, quality control issues, and its potential uses in environmental assessments of aquatic contaminants. Also, the suitability of the technique for incorporation with selected bioassays is examined.

Animals↗
PubMed1983

Triolein-cholesteryl oleate-cholesterol-lecithin emulsions: structural models of triglyceride-rich lipoproteins.

The organization of lipids within emulsions composed of triolein (TO), cholesteryl oleate (CO), cholesterol (C), and egg yolk phosphatidylcholine (L) was examined. CO was substituted for TO in a series of emulsions to obtain TO:CO ratios comparable to the triglyceride:cholesterol ester ratios observed in subfractions of triglyceride-rich lipoproteins. The weight fraction of TO in the surface phase (0.02-0.05) was independent of the TO content of the emulsions. However, the weight fraction of CO in the surface phase depended upon the percentage of CO in the emulsions and was less than 0.004 even when 13.7% CO was present in the emulsion. When CO was substituted for TO, the percent of the total particle C which was carried in the droplet oil phase was increased. The interparticle equilibration of lipids was studied in subfractions of sonicated emulsions with particle sizes comparable to triglyceride-rich lipoproteins. The TO:CO ratios of the subfractions of a given emulsion were constant and independent of size, but the C:L ratio decreased in particles of smaller diameter. However, the surface C:L ratio was the same in all particles from a given emulsion. The size dependence of the C:L ratios was attributed to the partitioning of C into the oil cores of the emulsions. Because large droplets have the greatest core:surface mass ratios, more of their total particle C is carried in the core.

Chemical Phenomena↗
PubMed1985

Molecular motions and thermotropic phase behavior of cholesteryl esters with triolein.

The phase behavior of cholesteryl esters with triglyceride has been characterized by differential scanning calorimetry (DSC), light microscopy, and polarizing light microscopy (PLM). Temperature-dependent molecular motions determined by 13C NMR spectroscopy were correlated with thermotropic phase behavior. Two systems, cholesteryl oleate (CO) and a 3/1 w/w mixture of cholesteryl linoleate (CL) and CO, were examined in the presence of small amounts of triolein (TO). Both systems exhibited metastable cholesteric and smectic (or only smectic) phases. Increasing amounts of TO progressively lowered the liquid-crystalline phase transition temperatures and eventually abolished the cholesteric phase, but at differing amounts of TO for the two systems (between 4% and 5% with CL/CO and between 7% and 10% with CO). DSC and PLM showed a progressive broadening of the phase transitions as well as an overlapping of the temperature ranges of the cholesteric and smectic phases. At greater than or equal to 4% TO, a separate isotropic liquid phase coexisted with liquid-crystalline phases. 13C NMR spectroscopy was used to monitor the molecular motions of the cholesteryl ester steroid ring and acyl chain in liquid and liquid-crystalline phases. In the liquid phase, no significant changes in fatty acyl motions, as reflected in spin-lattice relaxation time (T1) and nuclear Overhauser enhancement (NOE) values, were found on addition of TO. The line width (v 1/2) of the steroid ring resonances increased markedly near (1-5 degrees C above) the isotropic liquid----liquid-crystal phase transition temperature (TLC). However, the C3/C6 v 1/2 ratio at 1 degree C above TLC was greater for mixtures exhibiting an isotropic----cholesteric transition than for mixtures exhibiting an isotropic----smectic transition. Rotational correlation times calculated for motions about the long molecular axis and the nonunique axis showed (i) that the ring motions became more anisotropic as TLC was approached and (ii) that the motions were more anisotropic at TLC + 1 degree C for systems exhibiting a cholesteric phase than for systems exhibiting only a smectic phase. 13C line widths in spectra of the cholesteryl ester liquid-crystalline phases suggested that TO perturbed the cholesteryl ester intermolecular interactions and increased the rates of cholesteryl ester molecular motions relative to neat esters.

Calorimetry, Differential Scanning↗
PubMed1990

Phospholipid monolayers at the triolein-saline interface: production of microemulsion particles and conversion of monolayers to bilayers.

Interfacial tensions of phospholipid monolayer at the triolein (TO)-saline interface were measured. The adsorption isotherms and the interfacial pressure-molecular area curves were evaluated on the basis of the measurements. Phosphatidylcholine (PC) forms a highly condensed monolayer, with a large lateral attractive interaction; phosphatidylethanolamine (PE) and phosphatidylserine (PS) form expanded monolayers with smaller lateral interaction energies. At the lowest interfacial tension (the highest interfacial pressure), the mole fractions of PC, PE, and PS in the monolayers are estimated as 0.95, 0.73, and 0.88, respectively. Therefore, PC forms the most stable monolayer at the interface. These results are consistent with the finding that the stable TO particles in aqueous solution were produced by using PC as an emulsifier, and PE and PS did not stabilize the particles. The phase diagram of TO and PC mixtures in saline obtained from theoretical considerations predicts the equilibrium conversion of the monolayers on TO particles to bilayers. This process may be closely related to the transformations of very low density lipoproteins and chylomicrons to high-density lipoproteins in plasma. The particle sizes of the emulsion are calculated theoretically as a function of PC mole fraction in the TO-PC mixture and compared with the experimental values obtained from quasi-elastic light scattering (QLS) measurements.

Adsorption↗
PubMed1986

Evidence for conservation of dietary lipid in the rat during lactation and the immediate period after removal of the litter. Decreased oxidation of oral [1-14C]triolein.

Production of 14CO2 from an oral load of [1-14C]triolein was greatly decreased (70%) in lactating rats or immediately after (24-48 h) removal of the litter, compared with virgin rats. This decreased oxidation of dietary lipid was accompanied by accumulation of 14C-labelled lipid in lactating mammary gland or adipose tissue (after litter removal). No difference in 14CO2 production between lactating and virgin rats was observed when [1-14C]octanoate was administered. It is concluded that a major factor in this conservation of dietary triacylglycerol is the relative activity of lipoprotein lipase in the tissues.

Adipose Tissue↗
PubMed1994

Effects of tri-iodothyronine administration on the disposal of oral [1-14C]triolein, lipoprotein lipase activity and lipogenesis in the rat during lactation and on removal of the litter.

The effect of tri-iodothyronine (T3) administration on the utilization of dietary [14C]lipid by the mammary gland and adipose tissue of lactating and litter-removed rats was studied. (1) After an oral load of [1-14C]triolein, the lactating rats treated with T3 (50 micrograms/100 g body wt.) over 24 h showed an increase in 14CO2 production and a decrease in the total [14C]lipid transferred through the mammary gland that was paralleled by a decrease in tissue lipoprotein lipase (LPL) activity. (2) T3 administration decreased plasma prolactin in the lactating rats. Prolactin replacement in T3-treated rats restored LPL activity in the mammary gland, but did not increase the amount of dietary [14C]lipid transferred to the milk. (3) Chronic T3 administration (4 days) to lactating rats did not affect pup growth or the lipogenic rate in the mammary gland. (4) The administration of T3 to litter-removed rats inhibited the increase of LPL activity in white adipose tissue and decreased the accumulation of dietary [14C]lipid. This decrease was accompanied by increased 14CO2 production and [14C]lipid accumulation in skeletal muscle and heart. (5) It is concluded that hyperthyroidism depresses LPL activity in mammary gland and white adipose tissue, but not in muscle. The increased accumulation of [14C]lipid in muscle and increased production of 14CO2 in lactating and in litter-removed rats treated with T3 is in part due to the decreased total LPL in mammary gland and adipose tissue respectively, which are therefore less able to compete with muscle for the available plasma triacylglycerols.

Adipose Tissue↗
PubMed1992

Inhibition of repairable DNA-damage in Escherichia coli K-12 cells recovered from various organs of nitrosamine-treated mice by vitamin A, phenethylisothiocyanate, oleic acid and triolein.

The influence of various dietary constituents--phenethylisothiocyanate (PEITC), oleic acid (OA), triolein (TO), and vitamin A (ROL)--on the genotoxic activity of nitrosamines (NDMA, NDELA, NPYR) was investigated. For this purpose differential DNA repair assays with Escherichia coli K-12 strains were performed in vitro and in vivo with mice. Under in vitro conditions (liquid holding), all compounds reduced nitrosamine induced DNA-damage in the indicator bacteria in the dose range 1-10 micrograms/ml, the ranking order of efficiency being PEITC greater than OA greater than ROL greater than or equal to TO. In animal-mediated assays, acute oral treatment with PEITC (17-150 mg/kg), 2 h before nitrosamine administration, resulted in a marked decrease of nitrosamine genotoxicity in liver, kidneys, lungs and in the blood. Also in other organs (spleen, testes) an increase in differential survival (which serves as a measure for repairable DNA damage) occurred. With ROL only a comparatively moderate antigenotoxic effect was obtained at a high dose level (250 mg/kg) under identical experimental conditions. OA (2000 mg/kg) and TO (16,000 mg/kg) were completely inactive. Upon repeated treatment (consecutive oral administration of the putative antigenotoxins over 4 days, a final treatment 24 h before nitrosamine administration) PEITC (150 mg/kg/day), ROL (80 mg/kg/day) and OA (2000 mg/kg/day) had no influence on the genotoxic effects of the nitrosamines. Repeated treatment with TO (4000-16,000 mg/kg/day) resulted in a moderate dose-dependent reduction of NDMA-induced DNA-damage in the indicator bacteria, whereas in combination with NPYR only a marginal effect was observed. Biochemical experiments indicated that the antigenotoxic effects of PEITC seen under in vivo conditions were due to inhibition of alpha-hydroxylation of the nitrosamines, whereas ROL and TO appeared not to interfere strongly with this metabolic activation step. Our results indicate that in vitro assays do only partly reflect the antigenotoxic properties of the different food constituents in vivo and that animal-mediated DNA repair assays with E. coli strains are an appropriate approach to study the effects of modifiers of nitrosamine genotoxicity in the living animal.

Animals↗
PubMed1998

Digestion and absorption rates of [3H]-oleic acid and [14C]-triolein do not differ in rats fed heated (-) and (+) gossypol cottonseed and soybean flours.

This study was conducted to compare in vivo the acute effects of heated (+) and (-) gossypol cottonseed flours with those of soybean flour on lipid digestion and absorption in growing rats. Rats were fed by gastric intubation mixed [3H]-oleic acid and [14C]-triolein with heated flours or without flour (control). Lipid digestion and absorption were determined for 6 h after meal intubation. Both radioactivities recovered in gastrointestinal tract were significantly higher in rats fed (+) gossypol cottonseed flour than in all other groups. The majority of both recovered radioactivities was found in stomach contents, then in stomach wall and finally in intestinal wall. The distribution of both radioactivities at different gastrointestinal levels was similar. In stomach contents and wall, [14C]-radioactivity was primarily in triacylglycerols, but was also recovered in free fatty acids and diacylglycerols. In intestinal wall (mucosa + tunica) [3H]-radioactivity was found at greatest levels in free fatty acids, then in triacylglycerols and diacylglycerols. Greatest [14C]-radioactivity was found in triacylglycerols, then in free fatty acids, in diacylglycerols and last in phospholipids in rats fed the three flours. Therefore no quantitative differences in lipid digestion and absorption were observed among the rats fed the three flours. In conclusion, both cottonseed flours slowed lipid digestion and absorption compared with soybean flour and this delay was greater in the rats fed (+) gossypol cottonseed flour than in those fed (-) gossypol cottonseed flour. However, this inhibiting effect was probably too low to induce physiologically important effects on lipid digestion or absorption.

Animals↗
PubMedDate not supplied

Measurement of fat absorption utilizing 131iodine-triolein and nonabsorbable radioactive markers.

To eliminate many of the practical problems inherent in the collection of feces and in the chemical determination of fecal fat, a radioactive marker (131Ba) was combined with a labeled fat (131l-triolein) to measure fat absorption in man. The ratios of radioactivity of 131Ba/131l in a prepared capsule and that found in a random "grab" stool specimen after oral administration of the capsule were compared to determine the amount of fat absorbed. In an initial 36 patients, this double-label technique accurately separated normal from abnormal fat absorption as determined by the usual methods of quantitative fecal fat measurement. Results in an additional 102 patients and in 26 normals accurately reflected their clinical states. In addition, in vitro studies demonstrated more complete recovery of added lipid (99 percent) by radioactive techniques than by chemical analysis (86 per cent). The double-label technique not only seems more accurate than usual quantitative fecal fat determinations, but also greatly simplifies the measurement of fat absorption in man by eliminating the need for special diets, quantitative stool collections, and chemical analysis of stool.

Barium↗
PubMed1987

[14C]-triolein absorption: a useful test in the diagnosis of malabsorption.

The [14C]-triolein absorption test has been assessed using a preprepared fat meal in a procedure that can be completed within a working day on an inpatient or outpatient basis. An initial study showed complete discrimination between 30 control subjects and 13 patients with raised faecal fat excretion. A prospective evaluation in 57 patients under investigation for gastrointestinal disease showed a sensitivity of 85% and specificity of 93% (100% if two obese subjects are excluded). The test discriminates satisfactorily between patients with and without fat malabsorption and makes the measurement of faecal fat unnecessary in most circumstances.

Adult↗
PubMed1989

14C triolein breath test: an assessment in the elderly.

14C triolein breath tests are highly sensitive in detecting fat malabsorption in adults, but experience in the elderly is sparse. We have evaluated 48 'normal' subjects over the age of 65 years and compared the results with those of 46 normal subjects under 65 from a previous study. Results were calculated as eight hour cumulative values and expressed as percentages of the administered dose. Reference ranges have been calculated separately for the following age groups: 65 years or less (201 to 460), 66 to 75 (182 to 405) and over 75 (141 to 336). A clear age related decline in eight hour cumulative values was noted. The values fell by 23% between the ages of 17 and 65 years and by 25% between the ages of 65 and 87 years. Pancreatic insufficiency or bacterial colonisation of the small bowel is unlikely, but delayed intestinal absorption or the effects of slower metabolic rate cannot be excluded. This test is simple and practicable in the elderly and the study emphasises the importance of age in the interpretation of results.

Aged↗
PubMed1980

Tissue distribution of 14C-labelled triolein in a soybean oil emulsion. An autoradiographic study in rat and mouse.

A fed and a starved group of mice were injected with a 14C-labelled triolein emulsion, similar to Intralipid, in a dose corresponding to 0.1 mg triglyceride per gram body weight. The animals were sacrificed from 30 sec to 24 h after injection. The tissue distribution of the fat emulsion depended on the nutritional state of the animals. A marked concentration of radioactivity was found in the gastric mucosa of all animals as soon as 30 sec after injection which declined with time but was still clearly discernible in the autoradiograms 24 h after injection. Although the radioactivity only demonstrates the presence of the labelled oleic acid without indication of the degree of triglyceride lipolysis, the autoradiograms showed marked differences in the concentration of radioactivity between the various groups of skeletal muscles and between the different parts of the reticulo-endothelial system.

Animals↗
PubMed1983

[In vitro study of the lipase activity of bacterial strains isolated from the rabbit cecum on C14-labeled triolein].

The lipase activity of bacterial species isolated from the caecum of conventional rabbits was studied by means of two groups of tests: (1) bacteriologic isolation and an identification of nine aerobic and anaerobic clones and (2) incubation of each of these clones in the appropriate medium in the presence of labelled triolein (oleyl 1-14C), a biochemical analysis of the radioactivity of the fractions obtained. The main results can be expressed in the following way: maximum hydrolysis of glycerides is achieved by two species: Bacillus licheniformis and Clostridium sporogenes. The reaction is proportional to the incubation time for incubations of less than 8 h. The release of fatty acids is concomitant to the synthesis of phospholipids and of fatty acid methyl esters.

Animals↗
PubMed1984

Is the 14C-triolein breath test useful in the assessment of malabsorption in clinical practice?

A 14C-triolein breath test was carried out on 49 subjects suffering from chronic pancreatitis or from other digestive diseases, and its results were compared with the daily fecal fat excretion. The 14CO2 peak excretion was abnormal in all the subjects with a fecal fat excretion above 14 g/day, whereas individual values of 14CO2 peak excretion in subjects without steatorrhea and with a fecal fat excretion ranging from 7.1 to 14 g overlapped. The lowest value observed in patients not suffering from steatorrhea was chosen as the lower normal limit of 14CO2 peak excretion. A test sensitivity as high as 64% was attained. The correlation between fecal fat and 14CO2 peak excretion was highly significant (r = 0.802; p less than 0.0001), and it followed a negative exponential function. Therefore, small variations in the 14CO2 peak excretion can be associated with a wide range of fecal fat excretion. Well-compensated diabetes secondary to pancreatitis did not interfere with the results of the test. In conclusion, in our experience this test proved to be a qualitative diagnostic tool with a low sensitivity.

Adolescent↗