Lecithin Fraction Research Articles

Comparative study of modified soy lecithins as oil in water (O/W) emulsifiers.

Crude commercial soybean lecithin from two different sources named (A) and (C) were modified physically, chemically, and enzymatically using phospholipase A2 enzyme (PLA2) in order to improve their emulsification properties. All the modified lecithin fractions were used in the preparation of oil-in-water (O/W) emulsions, in comparison with the crude lecithins as well as a standard acetone-insoluble lecithin purchased from the market. The emulsions stabilized by acetone-insoluble fractions showed the best physical stability during 3 months of storage after preparation, along with a relatively low particle size (PS) and polydispersity index (PDI) and a zeta-potential values that indicates a good emulsion stability. Hydroxylated lecithin (H2A and H2C) showed the most stable Zeta-potential (-55.3 and -50.8 mV) respectively with a relatively low particle size and poly-dispersity index of 284.0 nm and 0.378 respectively for A and 268.4 nm and 0.391 for C, while hydrolyzed lecithin (ENZ A and ENZ C) that possessed the lowest particle size had a moderate zeta-potential of -34.8 and -32.2 for A and C respectively. These results showed that the modification of crude lecithin is essential for the production of tailor-made products with specific surface-active properties-stabilizing emulsions to be used in different purposes.

Fractionating of canola lecithin from acid degumming and its effect

In this study, lecithin obtained from acid degumming of canola oil was fractionated with absolute ethanol. The lipid composition and emulsifying properties of the resulting fractions were investigated. The results showed that phosphatidylcholine and lyso-phosphatidylcholine were greatly enriched in the ethanol soluble fraction (ESF), accounting for 43.79% and 13.21% of ESF, respectively. Phosphatidylinositol, lyso-phosphatidylinositol and phosphatidic acid, as a group, were enriched in the ethanol insoluble fraction (EIF), accounting for 37.4% of EIF. ESF and EIF promoted oil/water (o/w) emulsions as stable as the parent canola lecithin. EIF was not better than the parent lecithin as w/o emulsifier. This information is critical for evaluating the potential utilization of these canola lecithin fractions as emulsifiers or sources of specific phospholipid.

Unsaturated fatty acids supplementation reduces blood lead level in rats.

Some dietary factors could inhibit lead toxicity. The aim of this study was to evaluate the effect of dietary compounds rich in unsaturated fatty acids (FA) on blood lead level, lipid metabolism, and vascular reactivity in rats. Serum metallothionein and organs' lead level were evaluated with the aim of assessing the possible mechanism of unsaturated FA impact on blood lead level. For three months, male Wistar rats that were receiving drinking water with (100 ppm Pb) or without lead acetate were supplemented per os daily with virgin olive oil or linseed oil (0.2 mL/kg b.w.) or egg derived lecithin fraction: “super lecithin” (50 g/kg b.w.). Mesenteric artery was stimulated ex vivo by norepinephrine (NE) administered at six different doses. Lecithin supplementation slightly reduced pressor responses of artery to NE. Lead administered to rats attenuated the beneficial effect of unsaturated FA on lipid metabolism and vascular reactivity to adrenergic stimulation. On the other hand, the super lecithin and linseed oil that were characterized by low omega-6 to omega-3 ratio (about 1) reduced the blood lead concentration. This effect was observed in lead poisoned rats (p < 0.0001) and also in rats nonpoisoned with lead (p < 0.05).

Emulsifying Properties of Lecithin Containing Different Fatty Acids Obtained by Immobilized Lecitase Ultra‐Catalyzed Reaction

AbstractLecitase Ultra and 6 triacylglycerol lipases (lipases PS, M, AH, AY, R, and AK) were immobilized on Amberlite XAD 7HP and used to catalyze the acidolysis reaction between lecithin and capric acid (C10:0) for comparison. The highest molar incorporation value (51.0 mol%) was observed for the immobilized Lecitase Ultra. Further, immobilized Lecitase Ultra was selected for catalyzing acidolysis between lecithin and fatty acids with different chain lengths (C6:0, C8:0, C10:0, C12:0, and C14:0). After reaction, free fatty acids were removed by SPE and the resultant was called modified lecithin fraction 1 (MLF1). The highest molar incorporation value was obtained for C10:0 (51.0 mol%) at 45 °C with a mole ratio of 10/1 (C10:0/lecithin) for 72 h. After removal of lysophosphatidylcholine by solid‐phase extraction from MLF1, the resultant modified lecithin fraction 2 (MLF2) was used to prepare an oil‐in‐water emulsion. All emulsions prepared with MLF2 exhibited significantly higher emulsion stability (ES) values (16.2–17.7) and smaller particle sizes (d32 0.40–0.49 μm, d43 0.75–1.01 μm) than the emulsion prepared with unmodified lecithin (ES 14.1, d32 0.76 μm, d43, 1.26 μm) (P &lt; 0.05). Furthermore, less clarification and droplet aggregation were observed in emulsions prepared with MLF2 than in lecithin‐based emulsions. Overall, the MLF2s showed better emulsifying properties than lecithin.

Оцінка зв’язків показників жирнокислотного складу ліпідів легеневого сурфактанту з вмістом 137Сs в організмі дітей, які проживають на радіоактивно забрудненій території

An evaluation of correlation between fatty acid composition in pulmonary surfactant lipids and 137Cs content in the body of children, residents of radiation- contaminated areas revealed that an increased incorporation of 137Cs promotes a disruption of fatty acid balance towards an increase in the saturation of the surfactant lipid complex, a destruction of lecithin fraction of surfactant, a de-crease in antioxidant properties of surfactant system, an activation of lipid peroxidation processes in the respiratory area of lung by lipoxygenase type, a disturbance of polyunsaturated fatty acid metabolism on the stage of bioregulators-eicosanoid formation.

A novel hydrophilic poly(lactide‐co‐glycolide)/lecithin hybrid microspheres sintered scaffold for bone repair

Novel 3-D porous scaffolds made of sintered poly(lacide-co-glycolide) (PLGA)/lecithin hybrid microspheres (PLGA/Lec-SMS) were developed and investigated. The addition of lecithin in PLGA bulk successfully managed the desired hydrophilic modification without sacrificing bulk properties. The outcomes were verified with infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle analyses. Specifically, this model of scaffold gained significant improvement in mechanical (mainly compressive) strength upon an optimization of lecithin fractions aligning with sintering conditions. Given a perspective of bone tissue engineering use, human fetal osteoblasts were seeded into a series of these PLGA/Lec-SMS scaffolds upon which key parameters of cytocompatibility and osteoconductivity (including cell viability, alkaline phosphatase activity, calcium secretion, and osteogenic genes expression) were assessed. Osteoblasts seeded on PLGA scaffolds with 5 wt % lecithin demonstrated high cell viability and alkaline phosphatase activity. Moreover, elevated lecithin also enhanced the expression of type I collagen. Taken together, these results suggest PLGA/Lec-SMS are promising scaffolds for bone repair.

P39, a Novel Soybean Protein Allergen, Belongs to a Plant-Specific Protein Family and Is Present in Protein Storage Vacuoles

Soybean lecithins are seeing increasing use in industry as an emulsifier and food additive. They are also a growing source of human food allergies, which arise principally from the proteins fractionating with the lecithin fraction during manufacture. A previous study (Gu, X.; Beardslee, T.; Zeece, M.; Sarath, G.; Markwwell, J. Int Arch. Allergy Immunol. 2001, 126, 218-225) identified several allergenic proteins in soybean lecithins and a soybean IgE-binding protein termed P39 was discovered. However, very little was known about this protein except that it was coded by the soybean genome. This paper investigates key biological and immunological properties of this potential soybean lecithin allergen. P39 is encoded by a multigene family in soybeans and in several other higher plants. The soybean P39-1 protein and its essentially indistinguishable homologue, P39-2, have been cloned and studied. These proteins and their homologues belong to a family of plant-specific proteins of unknown function. In soybeans, P39-1 is seed specific, and its transcript levels are highest in developing seeds and decline during seed maturation. In contrast, P39 protein was detectable only in the fully mature, dry seed. Subcellular fractionation revealed that P39 protein was strongly associated with oil bodies; however, immunolocalization indicated P39 was distributed in the matrix of the protein storage vacuoles, suggesting that association with oil bodies was an artifact arising from the extraction procedure. By the use of recombinant techniques it has also been documented that IgE-binding epitopes are present on several different portions of the P39-1 polypeptide.

NAPUS 2000 Rapeseed (Brassica napus) breeding for improved human nutrition

Following a competition announcement of the Federal Ministry of Research and Education (BMBF) a project dealing with the improvement of the nutritional value of oilseed rape (Brassica napus) for food applications and human nutrition was worked out and started in autumn 1999. A number of partners (Figure 2) are carrying out a complex project reaching from the discovery, characterisation, isolation and transfer of genes of interest up to breeding of well performing varieties combined with important agronomic traits. Economic studies and processing trials as well as nutritional investigations of the new qualities are undertaken. B. napus seed quality aspects with respect to seed coat colour, oil composition, lecithin and protein fractions and antioxidants like tocopherols and resveratrol will be improved.

Design of a process for improvement of phosphatidylglycerol-phosphatidylinositol transfer protein recovery from Aspergillus oryzae

A novel highly active phosphatidylglycerol-phosphatidylinositol transfer protein (PG/PI-TP) was isolated from a cell-free extract of Aspergillus oryzae LMTC 2.14 grown on lecithin fractions as sole carbon source. A protocol for the extraction of the cytosolic PG/PI-TP that supports an extrapolation at industrial scale has been developed allowing the recovery of the active protein with high performance. Mycelium was harvested using a membrane press filter. A study of the cake permeability and compressibility which reflects the resistance of the cake to flow of liquid through pores was achieved in order to select the optimal working pressure (4×10 5 Pa). Mycelium disruption was achieved using a high-pressure homogenizer, with semi-continuous recycle. Two passes were necessary for an optimal recovery of PG/PI-TP. Removal of cell debris by filtration needed the use of 60 g l −1 Harbolite as filter aid. In the present growth conditions, mycelial intracellular lipid content was particularly high (≈40% of the mycelial dry weight) leading to major problems during chromatographic steps. In order to remove lipids, the crude extract was treated with hexane. Under these conditions, the crude extract was significantly clarified without loss of PG/PI-TP activity. As molecular filtration is not a suitable first chromatographic step in industry, ion-exchange chromatography was performed as a pre-purification step. Under these conditions, a recovery of 52% active PG/PI-TP was obtained, i.e. an improvement of 3.47-fold compared with previous work at labscale level.

Selective Inhibitors of Bitter Taste

The development of a method to mask bitter taste has been actively sought after in pharmaceutical and food science. A lipoprotein (PA-LG) was found in the present study to be composed of phosphatidic acid (PA) and β-lactoglobulin (LG) was noted to selectively and reversibly suppress frog taste nerve response and human taste sensation to various bitter substances without affecting sweetness, saltiness and sourness. PA would thus appear importantly involved in inhibiting bitterness since PA-containing lipoproteins showed inhibitory action irrespective of protein species. As for the mechanism of bitter suppression, PA-LG would appear to mask the receptor site for bitterness on taste receptor membrane. Inhibitory action forward bitterness by PA itself without protein or other phospholipids in humans was examined. PA and phosphatidylinositol (PI) inhibited the bitterness of various bitter substances without affecting the taste sensation of other taste stimuli, although inhibitory activity was less than that of PA-LG. A lecithin fraction containing high content PA and PI was thus prepared from soybean lecithin on an industrial scale. The lecithin fraction showed inhibitory activity forward bitterness. This fraction and PA were thus concluded effective means for masking the bitter taste of drugs and food.

Kinetic characterization of esterification catalyzed by Rhizopus delemar lipase in lecithin-AOT microemulsion systems

The esterification of oleic acid with octyl alcohol catalyzed by Rhizopus delemar lipase in microemulsion systems was investigated in terms of the kinetic parameters. The amphiphiles used were AOT and lecithin, both singly and as dual components. The enzyme activity in the lecithin system was high under hydrophobic conditions, i.e., at a W L ( [ H 2 O]/[ lecithin]) of 4.5, whereas in the AOT system it was high at W ( [ H 2 O]/[ AOT])  7. The reaction kinetics were recognized to follow the ping-pong bi-bi mechanism. A dual lecithin-AOT amphiphile system was effective in lipase catalyzed esterification, the maximum initial reaction rate being larger than those obtained in either of the single systems. The optimal molar fraction of lecithin for the maximum initial reaction rate differed with the water concentration in the microemulsion phase. Under relatively hydrophobic conditions, i.e., in a system with a lower W D ( [ H 2 O]/[ lecithin + AOT]), the initial reaction rate had a higher maximum value.

Stimulation of sexual reproduction in Phytophthora cactorum by phospholipids is not due to sterol contamination.

Phytophthora cactorum did not form oospores on basal medium unless phosphatidylcholine (lecithin) or phosphatidylethanolamine (cephalin) was added. After removal of putative sterols by aminopropyl column chromatography, the activities of lecithin and cephalin were increased 47- and 2.8-fold, respectively, thus confirming the previous reports that sterols are not essential for sexual reproduction in this organism. Thin-layer chromatography (TLC) of the commercial lecithin revealed the presence of an unknown inhibitory substance which, when added to the purified lecithin, caused a 50% reduction of oospore formation. Commercial cephalin also showed a twofold increase in activity after removal of putative sterols and the existence of an unknown inhibitor when it was subjected to TLC. Addition of the inhibitor to the purified cephalin completely inhibited the growth of the test organism. One sample of lecithin tested was not stimulatory to oospore formation. However, after washing with deionized water or NaCl solution, it induced the production of 17300 and 24450 oospores (100 μg)-1, respectively. The ability of cephalin to induce oospore formation was increased 2⋅3-fold by washing with deionized water and 8⋅3-fold by washing with NaCl solution. Like sterols, the digitonin precipitable component (digitonide) of the non-phospholipid fraction of commercial lecithin or cephalin was stimulatory to oospore formation of P. cactorum but not Phytophthora parasitica. However, the non-digitonide component was not only more active than the digitonide component, but also stimulatory to P. parasitica. Gas chromatography and mass spectrometry (GC-MS) analysis of the digitonide component from lecithin failed to detect any putative sterol contaminant. The amount of the putative sterol contaminant in the digitonide component from cephalin was also below the detection limit of GC-MS. When 0.01-10 ng cholesterol was added to basal medium discs each containing 100 fig cephalin, the numbers of oospores produced by P. cactorum and P. parasitica were not significantly changed. It is concluded that, in the fungi tested, sterols did not play any significant role in the stimulation of sexual reproduction by highly purified phospholipids.

Basic studies for the practical use of bitterness inhibitors: selective inhibition of bitterness by phospholipids.

We examined the effects of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol (PI), and phosphatidic acid (PA) on human taste sensation to various substances. The effects were evaluated psychophysically using paid volunteers. PA inhibited the bitterness of various substances dissolved in water without affecting sweetness, saltiness, and sourness, although its inhibitory activity was less than that of PA-LG. PI also showed inhibitory activity on bitterness, although its activity was less than PA. A soybean lecithin fraction containing high contents of PA and PI also demonstrated inhibitory activity on the bitterness of various substances. Both the incorporation of either PA or the lecithin fraction into granules containing quinine and the coating of the granules with PA or the fraction effectively inhibited the bitterness of quinine. The lecithin fraction is permitted for use as an additive to drugs and food and can be produced on an industrial scale. It is expected that the lecithin fraction will be used safely as a bitterness inhibitor for practical applications.

Complete mapping of crystallization pathways during cholesterol precipitation from model bile: influence of physical-chemical variables of pathophysiologic relevance and identification of a stable liquid crystalline state in cold, dilute and hydrophilic bile salt-containing systems

Using complementary physical-chemical techniques we defined five different crystallization pathways as functions of time (30 days) and increasing lecithin (egg yolk) content in pathophysiologically relevant model biles super-saturated (cholesterol saturation indices, 1.2 - 2.7) by dilution of approximately equal to 29 g/dl bile salt-lecithin-cholesterol micellar solutions. As evidenced by quasi-elastic light-scattering spectroscopy, supersaturation was heralded by the appearance of unilamellar vesicles. With the lowest lecithin contents, arc-like crystals with habit and density (d 1.030 g/mL) consistent with anhydrous cholesterol appeared first and evolved via helical and tubular crystals to form plate-like cholesterol monohydrate crystals (d 1.045 g/mL). With higher lecithin fractions, cholesterol monohydrate crystals appeared earlier than arc and other transitional crystals. With typical physiological lecithin contents, early liquid crystals (d 1.020 g/mL) were followed by cholesterol monohydrate crystals and subsequent appearances of arc and other intermediate crystals. With higher lecithin contents, liquid crystals were followed by cholesterol monohydrate crystals only, and at the highest lecithin mole fractions, liquid crystals appeared that did not generate solid crystals. Added calcium increased solid crystal number in proportion to its concentration (5 - 20 mM) but did not influence appearance times, crystallization pathways, or micellar cholesterol solubilities. Decreases in temperature (37 degrees --> 4 degrees C), total lipid concentration (7.3 --> 2.4 g/dL), and bile salt hydrophobicity (3 alpha, 12 alpha --> 3 alpha, 7 alpha, 12 alpha --> 3 alpha, 7 beta hydroxylated taurine conjugates) progressively shifted all crystallization pathways to lower lecithin contents, retarded crystallization, and decreased micellar cholesterol solubilities. The lecithin content of mother biles decreased markedly during crystallization especially where liquid crystals were a coexisting phase at equilibrium. This systematic study provides a framework for understanding cholesterol crystallization in human and animal biles and for examining factors that influence the kinetics of phase separation.

Antioxidative Effects of Oat Oil and its Fractions

AbstractThe antioxidative properties of oat oil and its fractions were studied using the Rancimat method and lard, tallow and soybean oil as substrates. Oat oil extracted with isopropanol increased the induction time of oxidation of lard and tallow from 2 to 8‐fold compared with the corresponding times without antioxidants, when applied at 1.0 to 5% concentrations. The same increase in stability was achieved with 0.25 to 1.5% concentrations of the separated fractions. The most effective fraction was the lecithin fraction isolated by supercritical CO2 extraction. Almost equal results were achieved with a single‐step ultrafiltration. Effects on the stability of soybean oil were similar but weaker.

Cooperativity in lipid activation of 3-hydroxybutyrate dehydrogenase: role of lecithin as an essential allosteric activator.

3-Hydroxybutyrate dehydrogenase (BDH) is a lecithin-requiring mitochondrial enzyme which catalyzes the interconversion of 3-hydroxybutyrate and acetoacetate with NAD(H) as coenzyme. The purified enzyme devoid of lipid (i.e., the apodehydrogenase or apoBDH) can be reactivated with soluble lecithin or by insertion into phospholipid vesicles containing lecithin. Two different models have been proposed to explain the sigmoidal lipid activation curves. For both models, activation of BDH is assumed to require the binding of two lecithin molecules per functional unit. Activation of soluble enzyme (dimeric form) by short-chain (soluble) lecithin is consistent with a model in which lecithin binding is noncooperative, whereas activation of the membrane-bound enzyme (tetrameric form) indicates cooperativity between the lecithin binding sites. A new comprehensive model is presented in which lecithin is considered to be an essential allosteric activator that shifts the equilibrium between conformational states of the enzyme. Resonance energy transfer data, reflecting NADH binding to membrane-bound and soluble apoBDH, are consistent with such a lecithin-induced conformational change. Apparent dissociation constants for binding of NADH to BDH are approximately 10 microM and approximately 37 microM for BDH activated by bilayer and soluble lecithin, respectively. The maximal fluorescence resonance energy transfer (delta F max) increases with higher mole fraction of lecithin in the bilayer. The largest changes occur between mole fractions 0 and 0.13, thereby correlating with enzymic function. Essentially no binding of NADH is observed in the absence of lecithin.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of Intestinal Disaccharidases with Phospholipids

Although the rat intestinal brush border disaccharidases are the most easily solubilized protein components, the nature of the lipid‐protein interactions in the membrane is incompletely understood. Phospholipid vesicles were prepared using the lecithin fraction from brush border membranes and synthetic lecithins. Addition of cholesterol to brush border lecithins enhanced the binding of disaccharidases, but not of alkaline phosphatase. The addition of cholesterol to synthetic lecithin vesicles enhanced the binding of disaccharidases only when added above the transition temperature of the lecithin used. The maximal effect occurred at an equimolar ratio of lecithin to cholesterol. Binding of disaccharidases to phospholipid vesicles was independent of charge or the nature of the polar head group, and the enzyme was inserted so that the catalytic domain was excluded from the lipid matrix. These results demonstrate that membrane attachment of disaccharidases is hydrophobic, involving primarily fatty acyl chains and an interaction with cholesterol. The membrane interaction does not seem to affect enzyme activity.

Interaction of intestinal disaccharidases with phospholipids: effect of cholesterol.

Although the rat intestinal brush border disaccharidases are the most easily solubilized protein components, the nature of the lipid-protein interactions in the membrane is incompletely understood. Phospholipid vesicles were prepared using the lecithin fraction from brush border membranes and synthetic lecithins. Addition of cholesterol to brush border lecithins enhanced the binding of disaccharidases, but not of alkaline phosphatase. The addition of cholesterol to synthetic lecithin vesicles enhanced the binding of disaccharidases only when added above the transition temperature of the lecithin used. The maximal effect occurred at an equimolar ratio of lecithin to cholesterol. Binding of disaccharidases to phospholipid vesicles was independent of charge or the nature of the polar head group, and the enzyme was inserted so that the catalytic domain was excluded from the lipid matrix. These results demonstrate that membrane attachment of disaccharidases is hydrophobic, involving primarily fatty acyl chains and an interaction with cholesterol. The membrane interaction does not seem to affect enzyme activity.

Fatty acids of sphingomyelin from amniotic fluid of normal and diabetic pregnancies

Amniotic fluid collected from 14 normal and 11 diabetic patients was analyzed for phospholipids, and separated sphingomyelin and lecithin fractions were further studied for their acid composition by gas liquid chromatography. Notable differences in percent fatty acid composition of sphingomyelin were observed for palmitic (16:0; diabetic less than normal), oleic (18:1; diabetic greater than normal), behenic (22:0; diabetic less than normal) and arachidic acid (20:0; absent in diabetics) in the specimens studied. Notable differences were not observed in fatty acids from lecithin fraction. Fatty acid composition of sphingomyelin from amniotic fluid is similar to fatty acid distribution in sphingomyelin from serum and erythrocyte and suggests maternal origin of the lipid.

The interaction of polysilicic acid with mixed films of cholesterol and dihexadecyllecithin

Silicic acid provokes the expansion of both pure dihexadecyllecithin films and mixed cholesterol—dihexadecyllecithin films containing more than 60% of phospholipid. On silica-free substrates the plot of the mean molecular area against the composition of the mixed system showed a large negative deviation from ideal behaviour, particularly at low surface pressure, for which the graph shows inflections when the mole fraction of lecithin is 0.5 or 0.8. On silicic acid substrates the condensation caused by cholesterol is more noticeable, and there is no sharp inflection in the mean molecular area plot. These results are interpreted as suggesting that silicic acid causes a change in the orientation of the phosphatidylcholine group of the lecithin, as a result of which the electrostatic repulsion between neighbouring molecules becomes greater, leading to more expanded films.