bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatty acid selectivity: The selectivity of lipases ofGeotrichum candidum
Authors: Sonnet Philip E. , Foglia Thomas A. , Baillargeon Mary Welch 
Published: January 2007

AbstractThe relative reactivities of several long‐chain fatty acids in esterifications with 1‐butanol catalyzed by lipases ofGeotrichum candidum were evaluated. As has been noted previously, these lipases are not uniformly highly selective forcis‐9 unsaturated fatty acids. However, the lipase preparations examined do uniformly discriminate against fatty acids having a chainlength greater than C‐18 such as erucic acid. The reactivities of γ‐linolenic and ricinoleic acid were also low compared to that of oleic. An examination of the effect of the alcohol upon the relative reactivities of acids showed that one could enhance fatty acid selectivity by proper choices of alcohol. For example, oleic acid esterifies 2.5 times faster than palmitic acid with 1‐butanol catalyzed by Amano GC‐4 lipase, but esterifies over 50 times faster with 2‐methyl‐1‐propanol or cyclopentanol.
Oil‐solids separation in edible oil processing
Authors: Latondress E. G. 
Published: January 2007

AbstractSedimentation, centrifugation and filtration are the methods used in the edible oil industry to separate oils and solids. In many instances, the choice of separation method is based more on economics than technical reasons because more than one method of separation accomplishes the desired end result. Increasing manufacturing costs have brought about the development of automated filtration systems so that only one operator is needed for a battery of filters. Centrifuges are being used in applications formerly reserved only for filters and new processes have been developed that make former batch separation processes continuous. These developments have had the goal of maintaining separating efficiencies while reducing costs and increasing sanitation.
Lipase‐catalyzed interesterification of oils and fats
Authors: Macrae A. R. 
Published: January 2007

AbstractExtracellular microbial lipases can be used as catalysts for the interesterification of oils and fats. Use of specific lipases gives products which are unobtainable by chemical interesterification methods. Some of these products have properties of value to the oils and fats industry. The catalysts for enzymatic interesterification are prepared by coating inorganic support materials with the lipases. For batch interesterification reactions, the catalyst particles are activated by addition of a small amount of water and then stirred with a reactant mixture dissolved in petroleum ether. At the end of the reaction period, the catalyst particles are removed by filtration, and the interesterified triglycerides isolated by conventional fat fractionation techniques. The catalyst can be used in subsequent batch reactions. As an alternative to the batch reaction system, continuous enzymatic interesterification processes can be operated by pumping water containg feedstock through a packed bed of activated catalyst.
Quality requirements and economic values in trading of oils
Authors: Shave D. A. 
Published: January 2007

AbstractIn view of the large amount of fats and oils produced, traded and consumed, the number of real quality problems is very low. The most significant quality terms — GMQ (generally merchantable quality) and FAQ (fair average quality) — can define trading terms in most cases. However, there is still a need to develop simple, rapid analyses with simple equipment to aid in the definition of trading terms.
Energy conservation in solvent extraction
Authors: Dada S. 
Published: January 2007

AbstractIncreased costs for energy and unpredictable supplies of fuel have created a new dimension in business management. Energy and solvent costs account for 40–50% of total costs in operating an oilseed solvent extraction plant in the USA. Many companies are finding that an organized energy conservation program can hold down both energy use and costs without disrupting plant production. It has been repeatedly demonstrated that conservation measures can reduce energy by 15–30% or more with justifying cost savings. More importantly, if by energy conservation you can maintain production despite a reduction in energy supply, or increase production in the face of frozen fuel allocations, the effect on your sales and profits is obvious.
Ultimate energy possibilities in conventional solvent extraction
Authors: Schumacher H. 
Published: January 2007

AbstractA short historical background and present state‐of‐the‐art for energy consumption in a complete soybean processing plant is provided. This includes bean drying, preparation, extraction, distillation, desolventizing, meal drying and cooling and lecithin production. The paper details how to achieve a much lower energy consumption than is obtained in today's conventional plant operation.
Use of microelectronics to upgrade process control into production control
Authors: von Klösterlein C. B. , Vos H. J. 
Published: January 2007

AbstractProcess control in oil extraction and processing is traditionally done by independent control loops and logic (sequence) controls. In the best case, all controls are located in one central control room. The operator's task is to draw the right conclusions from the process conditions signalled to him, to coordinate, to plan and to keep logsheets. On the basis of this information, he can coordinate between control loops and optimize unit operations. With the application of modern microelectronic‐based control systems (integrated control systems), it is possible to present the operator's information on a higher level (e.g., yield figures and energy consumptions computed from basic data), to do computerized planning operations and updatings, and to retrieve data which are used as an input for accounting systems and management information systems. Underlying principles, means for implementation, as well as benefits (both proven and potential) are described. The available hardware and software packages hardly form any limitations; on the contrary, we must often limit ourselves to optimal use of the available tools and not fall into the trap of “maximal automation.” Our aim is not to automate and control as much as possible, but to use automation as one of the means to process oilseeds and edible oils with the highest possible efficiency.
Effect of magnesium deficiency on post‐heparin lipase activity and tissue lipoprotein lipase in the rat
Authors: Rayssiguier Y. , Noé L. , Etienne J. , Gueux E. , Cardot P. , Mazur A. 
Published: January 2007

AbstractPrevious studies have provided evidence that Mg deficiency affects lipid metabolism. The present experiments were designed to assess whether the hypertriglyceridemia associated with Mg deficiency was related to alterations in post‐heparin lipase activity (PHLA). Mg‐deficient and control diets were pair‐fed to weanling Wistar rats for eight days and plasma lipoproteins were separated into various density classes by sequential preparative ultracentrifugation. Triglycerides were significantly increased in chylomicrons and in the very low density lipoprotein, low density lipoprotein and high density lipoprotein (HDL) fractions. Cholesterol and phospholipid levels were significantly lower in the HDL fraction. PHLA in deficient rat was substantially lower than in control rats. The inverse correlation between plasma triglyceride concentration and PHLA strongly suggests that hypertriglyceridemia is the result of defective lipolysis of plasma triglycerides in Mg‐deficient rats. Further examination of the PHLA was carried out by salt‐mediated inhibition of lipoprotein lipase (LPL) and by heparin sepharose affinity chromatography and purified rat LPL antiserum. The results indicate that hepatic lipase is significantly decreased in Mg‐deficient rats but the low PHLA is due mainly to a decline in LPL. However, total LPL activity, that is, both the intracellular and the extracellular oools of LPL in adipose tissue, heart and diaphragm, were unaffected by Mg deficiency. The results suggest that the decrease of LPL activity in the plasma of Mg‐deficient rats may be due to a selective decrease in the heparin‐releasable pool of enzyme.
Acyl‐CoA:cholesterol acyltransferase activity in the rat mammary gland: Variation during pregnancy and lactation
Authors: Shand J. H. , West D. W. 
Published: January 2007

AbstractCholesterol esterification by acyl‐CoA:cholesterol acyltransferase (ACAT; EC 2.3.1.26) has been studied in microsomes isolated from the mammary glands of rats in late pregnancy, in early and mid‐lactation, and following premature weaning. The mammary glands were freeze‐clamped and the microsomes prepared in the presence of phosphatase inhibitors to preserve the phosphorylation status of the enzyme. Optimal conditions were established for the assay of enzyme activity in the presence of endogenous cholesterol. Supplementation of the microsomes with exogenous cholesterol as a dispersion in Triton WR‐1339 was shown to lead to an increase in enzyme activity. Incubation of microsomes with MgATP led to an increase in ACAT activity which could be reversed by treatment of the microsomes with a phosphoprotein phosphatase preparation from rat liver. The results suggested that ACAT activity in the mammary gland was activated by phosphorylation in a similar way to that observed for the hepatic enzyme. The mammary glands from pregnant animals contained a higher level of ACAT activity than did the glands of the lactating animals and this correlated with the higher cholesteryl ester content of the pregnant glands. The highest level of ACAT activity was found in the weaned animals but the cholesteryl ester content of the microsomes was lower than expected. The influence of progesterone levels and changes in feeding patterns during gestation were considered as factors in these variations in ACAT activity.
Inhibition of acylcoenzyme A:Cholesterol acyltransferase activity by PD128O42: Effect on cholesterol metabolism and secretion in CaCo‐2 cells
Authors: Jeffrey Field F. , Albright Ella , Mathur Satya 
Published: January 2007

AbstractThe regulation of cholesterol uptake and secretion by acylcoenzyme A:cholesterol acyltransferase (ACAT) was investigated in the human intestinal cell line, CaCo‐2. A new ACAT inhibitor, PD128042 (CI‐976), was first characterized. The addition of the fatty acid anilide to membranes prepared from CaCo‐2 cells inhibited ACAT activity without altering the activities of HMG‐CoA reductase, fatty acid Co‐A hydrolase, or triglyceride synthetase. PD128042 was a competitive inhibitor of ACTA with 50% inhibition occurring at a concentration of 0.2 μg/mL. When added to the medium of CaCo‐2 cells at a concentration of 5 μg/mL, PD128042 inhibited oleate incorporation into cholesteryl oleate by 92% and increased oleate incorporation into triglycerides and phospholipids by 51% and 38%, respectively. After incubating CaCo‐2 cells with the ACAT inhibitor, the rate of newly synthesized cholesterol decreased by 75% and membranes prepared from these cells contained significantly less HMG‐CoA reductase activity. PD128042 significantly decreased the basolateral secretion of newly synthesized cholesteryl esters without affecting the secretion of newly synthesized triglycerides or phospholipids. The inhibitor decreased the esterification of labeled exogenous cholesterol which was taken up by the cell from bile salt micelles. Moreover, after 16 hr of ACAT inhibition, less labeled unesterified micellar cholesterol was associated with the cell. The esterification of cholesterol in CaCo‐2 cells plays an integral role in the uptake of cholesterol through the apical membrane and its eventual secretion at the basolateral membrane.
Lipid and fatty acid composition is altered in plaque tissue from multiple sclerosis brain compared with normal brain white matter
Authors: Wilson Robert , Tocher Douglas R. 
Published: January 2007

AbstractPlaques and white matter from brains of multiple sclerosis (MS) patients were analyzed for lipid content, class composition, and fatty acid composition of total lipid, together with the fatty acid composition of plaque glycerophospholipids, and the results were compared with white matter from normal brain. Plaques contained less than 30% of the lipid present in normal white matter. Plaque lipid was characterized by significantly increased proportions of glycerophospholipids and decreased cerebrosides and sulfatides. In addition, a subacute plaque contained approximately 10 times the proportion of steryl esters observed in chronic plaques or normal white matter. Total lipid from all the MS plaques showed significantly increased percentages of saturated fatty acids, n−6, n−3 and total polyunsaturated fatty acids and decreased percentages of monoenes and alk‐1‐enyl ethers in comparison with normal brains. These results were consistent with increased cellularity and astrogliosis associated with MS plaques. However, analysis of plaque glycerophospholipids showed that the fatty acid changes observed in total lipid were not simply due to the increased proportion of glycerophospholipids and decreased myelin lipids, but that the fatty acid composition of the individual glycerophospholipids was different.
Vasopressin stimulates phospholipase D activity against phosphatidylcholine in vascular smooth muscle cells
Authors: Welsh Clement J. , Schmeichel Karen , Cao Hui‐ting , Chabbott Holly 
Published: January 2007

AbstractIt is now clear that various hormones and agonists can stimulate the production of lipid mediators from nonphosphoinositide phospholipids. We have investigated the production of diacylglycerol from nonphosphoinositide sources, and we demonstrated that vasopressin and other vasoactive agents stimulate hydrolysis of phosphatidylcholine in a variety of cultured vascular smooth muscle cells of rat and human origin. We used vasopressin to characterize this response and found that vasopressin stimulates phospholipase D activity against phosphatidylcholine in A‐10 vascular smooth muscle cells. The vasopressin‐stimulated phosphatidylcholine hydrolysis is both time‐ and concentration‐dependent. The half‐maximal dose of vasopressin required for phosphatidylcholine hydrolysis (ED50∼1 nM) correlates well with vasopressin binding to A‐10 cells (Kd∼2 nM). The phosphatidylcholine in A‐10 cells can be preferentially radiolabeled with [3H]myristic acid; subsequent treatment with vasopressin stimulates a rapid increase in3H‐labeled phosphatidate (∼4×control values at 3 min), and after a short lag,3H‐labeled diacylglycerol rises and reaches maximal levels at 10 min (∼2×control values). Similar temporal elevations of phosphatidate and diacylglycerol occur in A‐10 cells labeled with [3H]glycerol. In A‐10 cells radiolabeled with [3H]choline the elevation of cellular phosphatidate and diacylglycerol is concomitant with the release of [3H]choline metabolites (predominately choline) to the culture medium. The temporal production of phosphatidate and diacylglycerol as well as the release of choline to the culture medium are consistent with vasopressin activating phospholipase D. In addition, vasopressin stimulates a transphosphatidylation reaction that is characteristic of phospholipase D. The transphosphatidylation reaction is detected by the production of phosphatidylethanol that occurs when A‐10 cells are incubated with ethanol and stimulated with vasopressin. The phospholipase D is active in the absence of extracellular Ca++ whereas the vasopressin‐stimulated mobilization of arachidonic acid is dependent on extracellular Ca++. The data indicate that vasopressin stimulates phospholipase D which hydrolyzes phosphatidylcholine to phosphatidate. The phosphatidate is then metabolized, presumably by a phosphatidate phosphohydrolase, to produce sustained levels of cellular diacylglycerol. These sustained levels of diacylglycerol may activate protein kinase C and theraby function in the “sustained phase” of cellular responses.
Inhibitory effect of stearidonic acid (18∶4 n−3) on platelet aggregation and arachidonate oxygenation
Authors: Kockmann Véronique , Spielmann Danielle , Traitler Helmut , Lagarde Michel 
Published: January 2007

AbstractThe effect of stearidonic acid (18∶4n−3) present in fish and some plant oils, such as black currant seed oil, was studied on human platelets. When added to platelets simultaneously with collagen, arachidonic acid or endoperoxide mimetic U46619, 18∶4n−3 appeared as a weak inhibitor of platelet aggregation. In addition, 18∶4n−3 did not alter the metabolism of exogenous arachidonic acid. In contrast, when preincubated with platelets after precoating onto albumin, 18∶4n−3 inhibited platelet aggregation induced by thrombin, collagen, arachidonic acid or U46619, and was as potent as eicosapentaenoic acid (20∶5n−3) tested under similar conditions. Stearidonic acid also altered the endogenous arachidonate oxygenation stimulated by low doses of thrombin, but to a significantly lesser extent than did 20∶5n−3. It seems therefore that, in addition to competing with endogenous arachidonate metabolism, 18∶4n−3 may affect platelet aggregation by another mechanism.
A method for the simultaneous analysis of unconjugated and glycine‐conjugated bile acids by capillary gas‐liquid chromatography
Authors: Iida Takashi , Itoh Takako , Hagiwara Kayoko , Chang Frederic C. , Goto Junichi , Nambara Toshio 
Published: January 2007

AbstractA method for the simultaneous analysis of unconjugated and glycine‐conjugated bile acids by means of capillary gas‐liquid chromatography without need for prior deconjugation is described. The method involves: i) the use of an aluminum‐clad fused‐silica capillary column coated with a very thin film (0.1 μm) of a highly thermostable bonded and crosslinked methyl polysiloxane, and ii) the analysis of the bile acids as their methyl ester‐dimethylethylsilyl ether derivatives. This method, used to separate the major free and glycine‐conjugated bile acids from human gall bladder bile, should be applicable for the analysis of other biological fluids.
A simple photometric method for microdetermination of fatty acids in lipids
Authors: Chakrabarty M. M. , Bhattacharyya D. , Kundu M. K. 
Published: January 2007

AbstractA single step photometric micromethod for determination of fatty acids in lipids in benzene solution, using rhodamine 6G reagent, has been developed. The method eliminates the disadvantage of formation of a biphasic system and is applicable in the presence of glycerides, sterols, epoxy compounds, hydrocarbons and long chain hydroxy compounds such as long chain fatty alcohols. The long chain fatty acids from C12 to C22, both saturated and unsaturated, can be determined with reasonable accuracy in the concentration range of 0.08–0.25 µmole/ml. The method is simple, rapid, and requires relatively inexpensive chemicals.
Lipid‐lipid complexes: Properties and effects on lipase binding to surfaces
Authors: Brockman Howard L. , Momsen William E. , Tsujita Takahiro 
Published: January 2007

AbstractIn the presence of bulk water, the lipase‐catalyzed synthesis and hydrolysis of insoluble lipid esters occur at the lipid‐water interface. For water‐soluble lipases, a necessary step in this process is the partitioning of enzyme from the bulk aqueous phase to the surface phase. In surface phases of phospholipids and the substrates and products of lipolysis, physical studies have demonstrated the formation of preferred packing arrays or lipid‐lipid “complexes.” Such interactions involve changes in both lipid molecular area and hydration. Binding of pancreatic carboxylester lipase (cholesterol esterase) and colipase to monomolecular films of a phosphatidylcholine and its complexes with fatty acid or diglyceride is negligible. In contrast, saturation of film of pure fatty acid or diglyceride correlates with formation of a protein monolayer. With mixtures of complex and uncomplexed fatty acid or diglyceride, binding to the uncomplexed lipid occurs, but only with colipase can saturation of available sites be achieved. The lower affinity of carboxylester lipase for surfaces containing complexes can be qualitatively explained by differences in the size of lipid and protein molecules. Because it involves no direct interaction between enzyme and complex, such “proxinhibition” of enzyme binding is potentially an important regulation of lipid‐protein interactions.
Studies on free and immobilized lipases fromMucor miehei
Authors: Huge‐Jensen Birgitte , Galluzzo Donna Rubano , Jensen Robert G. 
Published: January 2007

AbstractAn extracellular lipase produced by fermentation with a selected strain ofMucor miehei has been purified partially in two forms: A and B. The forms have a high degree of antigenic identity and have similar pH‐activity profiles with tributyroylglycerol as the substrate with optima at pH 7. The differences are A, in contrast to B, requires activation at alkaline pH before analysis; A binds with concanavalin A more completely than B, the net charges are slightly different at pH 8; the isoelectric points are different. Our results indicate that the B lipase is formed by partial deglycosylation of the A lipase and that this influences the activity toward emulsions.The two enzymes have been immobilized by adsorption. These preparations and the soluble forms were highly specific for primary ester of triacylglycerols (TG), usually hydrolyzed TG of 12:0, 14:0, 16:0 and 18:1 more rapidly than those of 4:0, 6:0, 8:0 and 10:0 in mixtures of monoacid TG (4:0 to 18:1), and were not stereospecific for TG. Immobilization altered the specificity of the preparations somewhat in that slightly more 14:0 and 16:0 were released.
Evidence for the probable presence of sulfur‐containing fatty acids as minor constituents in canola oil
Authors: Wijesundera R. C. , Ackman R. G. 
Published: January 2007

AbstractThree isomeric epithio stearic acids have been concentrated as possible minor sulfur‐bearing components of unprocessed canola oil. Chromatographic and mass spectral evidence is presented in support of these novel fatty acid structures, tentatively identified as isomeric 9, 12; 8, 11; and 7, 10 epithio stearic acids, each with a methyl substituent on the ring.
A mechanistic approach to the thermal degradation of α‐olefin sulfonates
Authors: Hu P. C. , Tuvell M. E. 
Published: January 2007

AbstractDetermination of the thermal stability of α‐olefin sulfonates (AOS) via the conventional activation energy approach was found to be impractical because of the difficulties arising from the fact that α‐olefin sulfonates are mixtures of hydroxyalkane sulfonates and alkene sulfonates. Each of these components of AOS was studied independently and found to follow a complicated thermal degradation path.We found that the thermal degradation of hydroxyalkane sulfonate is a base‐catalyzed process. At elevated temperatures, hydroxyalkane sulfonates are first converted into an intermediate which is still surface active before degrading further to a non‐surface active product by a second mechanism. The rate‐determining step of the degradation process was found not to involve a cleavage of the C‐S bond as observed for other types of sulfonates.Our work indicates that the first step of the thermal degradation of alkene sulfonates involves isomerization of double bonds followed by cleavage of the C‐S bond. The thermal degradation of alkene sulfonates is catalyzed by acids.