Yields Of Free Fatty Acids Research Articles

Polyunsaturated Fatty Acid Concentrates of Carp Oil: Chemical Hydrolysis and Urea Complexation

AbstractThe aims of this study were to compare three treatments in the chemical hydrolysis reaction of bleached oil from carp (Cyprinus carpio) heads and to obtain polyunsaturated fatty acid concentrates by urea complexation. The three treatments were carried out with different oil:ethanol molar ratios. In the treatment with a 1:39 molar ratio, a higher yield of free fatty acids was found. These fatty acids were submitted to urea complexation (−10 °C for 20 h, and urea–fatty acid ratio of 4.5–1). There was a 31.4% increase in monounsaturated and polyunsaturated fatty acids (MUFA and PUFA) content and a 75% decrease in saturated fatty acids (SAF) content. An increase of 85.4% in the EPA + DHA content was found. The non‐urea complexing fraction can be considered a rich source of MUFA and PUFA with a total amount of 88.9%.

10.1007/s11827-008-1008-5

It is generally recognized nowadays that active lipid metabolism takes place in the nucleus of a mammalian cell. Experimental data testify to the biosynthesis of polyphosphoinositides and phosphatidylcholine and reveal corresponding enzymes within nuclei of mammalian cells. These findings suggest that lipidmediated signaling pathways in nuclei operate independently of lipid-mediated regulatory mechanisms functioning in membranes and cytosol. To explore the pathways of intranuclear lipid biosynthesis, we studied incorporation of 2-14C-acetate into lipids of cytosol and isolated nuclei of rat thymus cells after separate and combined incubation with the labeled precursor. The most efficient incorporation of 2-14C-acetate into lipids (cholesterol, free fatty acids, and phospholipids) was observed in a reaction mixture containing cytosol. When the reaction mixture contained only nuclei, incorporation of the radioactive precursor into lipids also took place, but specific radioactivity of the lipids was essentially lower than in the cytosol. In both cases, 2-14C-acetate incorporated into phosphatidylethanolamine, sphingomyelin, phosphatidylserine, phosphatidylinositol, and cardiolipin. Phosphatidylcholine, the most abundant membrane phospholipid, demonstrated the lowest radioactivity, which was significantly lower than that of phosphatidylethanolamine. Incorporation of newly synthesized free fatty acids in nuclear phospholipids was inhibited, if nuclei were incubated with cytosol. As a result, radioactive free fatty acids were accumulated in nuclei, while in cytosol they were efficiently incorporated into phospholipids. The levels of phospholipids and cholesterol remained constant regardless of incubation protocol, while the overall yield of free fatty acids decreased after combined incubation of nuclear and cytosolic fractions or after incubation of cytosol without nuclei. Putative mechanisms underlying the appearance of radioactive lipids in isolated nuclei of thymus cells are discussed.

Release of short chain fatty acids from cream lipids by commercial lipases and esterases

Lipases and esterases are frequently used in dairy production processes to enhance the buttery flavour of the end product. Short chain fatty acids, and especially butanoic acid, play a key role in this and different enzymes with specificity towards short chain fatty acids are commercially available as potent flavouring tools. We have compared six lipases/esterases associated with buttery flavour production. Although specificity to short chain fatty acids was ascribed to each enzyme, clear differences in free fatty acid profiles were found when these enzymes were applied on cream. Candida cylindraceae lipase was the most useful enzyme for buttery flavour production in cream with the highest yield of free fatty acids (57 g oleic acid 100 g(-1) fat), no release of long chain fatty acids and specificity towards butanoic acid.

Bitter taste of unsaturated free fatty acids in emulsions: contribution to the off-flavour of soybean lecithins

The contribution of (poly-) unsaturated free fatty acids (FFAs) to the bitterness of soybean lecithins was investigated by an analytical-chemical and by a sensory approach. Standardized, hydrolyzed, deoiled, and fractionated soybean lecithins were characterized by taste profiles and their yields of FFA were quantified. Threshold tests revealed the polyunsaturated free linoleic acid (cis-9, cis-12-octadecadienoic acid) and free linolenic acid (cis-9, cis-12, cis-15-octadecatrienoic acid) as the FFAs with the lowest bitter taste thresholds in emulsion and the highest impact on the off-taste problems of soybean lecithins and their applications. These results were confirmed by sensory model mixtures. Furthermore, the relationship between FFAs and the perceived bitterness in dependency on the emulsion and the intensity of FFA bitterness in correlation to the FFA concentration were investigated.

Synthesis of monoglycerides by glycerolysis of rapeseed oil using immobilized lipase

AbstractReaction conditions for the synthesis of monoglycerides (MG) by enzyme‐catalyzed glycerolysis of rapeseed oil using Lipozyme® IM have been studied. Silica gel was used to adsorb the glycerol to overcome the problems of low glycerol solubility in the organic phase. An experimental design was used where temperature, time, the ratio of silica gel to glycerol (w/w), the water activity (a)w, the isooctane concentration, and the ratio of glycerol to triglycerides (mol/mol) were varied. Response surface methodology was used to evaluate initial reaction rate and yield for the different products. The best yield of MG achieved under the studied conditions was 17.4% (mol fatty acid in substance/total mol fatty acid in mixture) (75°C, 20 h, silica gel/glycerol 2:1, aw=0.17, 48% isooctane, glycerol/triglycerides 6:1). The same conditions yielded 36.8% diglycerides, 13.6% free fatty acids (FFA), and 36.9% triglycerides. This is at the same level as the equilibrium yield. The yield of MG is low compared to the final yield achieved with solid‐phase glycerolysis. However, in solid‐phase glycerolysis the reaction mixture becomes solid, and therefore the solid‐phase process is not suitable for industrial application. The formation of FFA was very fast compared to the synthesis of MG. Equilibrium for FFA was reached within 2 h, and the yield was strongly affected by the aw. Increasing aw greatly increased the formation of FFA. In the aw ratio 0.06–0.3, the yield of FFA increased from 4 to 19% while the yield of MG was nearly unaffected. As FFA is an undesired product, it is important to keep the aw as low as possible.

Lipase‐catalyzed triglyceride hydrolysis in organic solvent

An investigation of lipases fromRhizomucor miehei,Candida rug osa and porcine pancreas revealed that these enzymes hydrolyzed triglycerides in an organic solvent system. The presence of secondary amines,i.e., diethylamine,N‐methylbutylamine, or the tertiary amine, Methylamine, greatly increased the extent of hydrolysis. The lipolysis of tallow took place under mild conditions,e.g., room temperature, moderate shaking and within 20 hr. At 45°C, complete hydrolysis of tallow was obtained in 6 hr. Vegetable oils and a fish oil (cod liver oil) were also hydrolyzed at 20°C byR. miehei lipase in the presence of iV‐methylbutylamine for 20 hr. The lipases were recovered for reuse with some loss of activity. Optimum yields of free fatty acids were obtained by usingR. miehei lipase as catalyst.

Quantitative release of fatty acids from lipids by a simple hydrolysis procedure.

Glycerolipids and sphingolipids are hydrolyzed with 0.5 M HCl in acetonitrile-water 9:1 (by vol) for 45 min at 100 degrees C or 4 hr at 70 degrees C. After hydrolysis, free fatty acids (FFA) are recovered in chloroform and separated by thin-layer chromatography. More than 95% of the radioactivity from labeled phospholipids is recovered as FFA, and more than 97% of the lipid phosphorus is recovered as water-soluble phosphate. The yields of FFA, including polyunsaturated acids, after hydrolysis are as good as or better than those obtained for methyl esters using methanolysis catalyzed by acid, alkali, or BF3. High recoveries of FFA from glycerophospholipids, sphingomyelin, and neutral glycerides are attained. The procedure is quantitative, simple, inexpensive, and produces no methyl esters as secondary products.

Positional Specificity of Lipoprotein Lipase

Abstract The stereochemical course of hydrolysis of radioactive triolein was determined using lipoprotein lipase of cow's milk and rat postheparin plasma. [3H]Glycerol trioleate or glycerol [1-14C]trioleate was emulsified with total egg yolk lipids to provide 0.2 to 2.5 µCi of 3H or 0.03 µCi of 14C per µm substrate. The hydrolysis products were isolated at 1 to 45 min and free fatty acids and the various positional isomers of mono- and diglycerides were resolved by thin layer chromatography. In a total yield of 0.03 to 0.16 µmole of diglyceride, 9 to 30% was 1,3- and 70 to 91%, 1,2-(2,3-)diglyceride. The 2,3-isomer was 73 to 96% of the latter. The yield of free fatty acids and monoglycerides varied with the length of incubation. In 15 of 17 determinations, the 1-(3-)isomer accounted for 51 to 87% of the monoglyceride. It is suggested that lipoprotein lipase attacks preferentially position 1 in sn-glycerides and follows it by hydrolysis of the positions 2 and 3. An intermediate formation of 2,3-diglycerides during lipoprotein lipase hydrolysis may be important in avoiding stimulation of triglyceride and phospholipid biosynthesis which proceed via 1,2-diglycerides.