Soya Oil Emulsion Research Articles

Fatty Acid Supplied as Triglyceride Regulates SRE‐Mediated Gene Expression as Efficiently as Free Fatty Acids

Sterol regulatory element binding proteins (SREBPs) are key transcription proteins that bind to sterol regulatory elements (SRE) of genes essential for cellular cholesterol and fatty acid homeostasis. Polyunsaturated fatty acids (PUFA) strongly inhibit SREBP processing at post-transcriptional levels. We questioned if delivering PUFA as part of a triglyceride (TG) molecule would have similar effects and efficiency as free non-esterified PUFA. CHO cells stably transfected with an SRE-promoter linked to the luciferase reporter gene were incubated for 8-24 h with linoleic acid (LA) complexed to BSA (molar ratios 0.5-4:1), VLDL-sized trilinolein emulsions (TL, 25-200 microg/ml), and chylomicron-sized soy oil emulsions in the presence and absence of apoE. Effects of LA and TL on decreasing SRE-luciferase activity were similar and dose and time dependent. Both TL and LA significantly and rapidly (<or=2-12 h) reduced SRE-mediated gene expression by up to 75%. At equal fatty acid concentrations, SRE inhibition by TL was as effective as LA. ApoE addition increased inhibition by TL. Inhibition of gene expression was highly correlated to cell TG accumulation. We conclude that TG like fatty acids are rapid and efficient modulators of SRE-mediated gene expression.

Interactions between Whey Protein Isolate and Soy Protein Fractions at Oil–Water Interfaces: Effects of Heat and Concentration of Protein in the Aqueous Phase

ABSTRACT: The 2 main storage proteins of soy—glycinin (11S) and β‐conglycinin (7S)—exhibit unique behaviors during processing, such as gelling, emulsifying, or foaming. The objective of this work was to observe the interactions between soy protein isolates enriched in 7S or 11S and whey protein isolate (WPI) in oil–water emulsion systems. Soy oil emulsion droplets were stabilized by either soy proteins (7S or 11S rich fractions) or whey proteins, and then whey proteins or soy proteins were added to the aqueous phase. Although the emulsifying behavior of these proteins has been studied separately, the effect of the presence of mixed protein systems at interfaces on the bulk properties of the emulsions has yet to be characterized. The particle size distribution and viscosity of the emulsions were measured before and after heating at 80 and 90 °C for 10 min. In addition, SDS‐PAGE electrophoresis was carried out to determine if protein adsorption or exchanges at the interface occurred after heating. When WPI was added to soy protein emulsions, gelling occurred with heat treatment at WPI concentrations &gt;2.5%. In addition, whey proteins were found adsorbed at the oil–water interface together with 7S or 11S proteins. When 7S or 11S fractions were added to WPI‐stabilized emulsions, no gelation occurred at concentrations up to 2.5% soy protein. In this case also, 7S or 11S formed complexes at the interface with whey proteins during heating.

Adsorption of κ-casein onto native milk fat globule, latex particle, and emulsion surfaces

The adsorption of κ-casein onto three surfaces was examined: (1) native milk fat globules, (2) low charge density sulfated polystyrene latex particles coated with milk fat globule membrane (MFGM) material, and (3) MFGM-coated soy oil emulsions. Particle hydrodynamic diameter was measured using dynamic light scattering before and after addition of κ-casein, and also after subsequent addition of Mucor miehei rennet protease or trypsin. The thickness of MFGM coating on latex particles was 25 nm at pH <5.8 reducing to 10 nm at pH >6.4. There was no increase in diameter after adsorption of κ-casein onto MFGM-coated latex particles or soy oil globules. The radius of native fat globules decreased by 15–20 nm after κ-casein adsorption. Addition of rennet or trypsin to the latex or emulsion+MFGM+κ-casein system caused aggregation, providing indirect evidence of κ-casein adsorption. In most cases the aggregate size reached a plateau value within 12 min, except at pH 5.5 after addition of trypsin where aggregation continued for at least 25 min. A reduction in radius of around 10–20 nm occurred initially after the addition of rennet or trypsin to MFGM-coated latex particles at pH 6.7 and native fat globules at pH 5.5 and 6.0, both with an adsorbed secondary layer of κ-casein, providing evidence of steric stabilization by a κ-casein ‘hairy layer’. This did not occur for MFGM-coated soy oil globules with a κ-casein adsorbed layer.

Interactions of proteins and surfactants at oil–water interfaces: influence of a variety of physical parameters on the behaviour of milk proteins

Displacement of adsorbed β-casein from polystyrene latex and of caseinate from heated and unheated soya oil and tetradecane oil-in-water emulsions by the non-ionic detergent, Tween 20, has been studied. Protein was displaced more readily from the tetradecane emulsion than from the corresponding soya oil. Heating decreased the amount of protein displaced from the soya oil emulsion but had little effect on displacement from tetradecane. Ageing decreased the amount of protein displaced from the soya oil emulsion, but the effects of heating were less pronounced in aged soya oil emulsions. The effect of pH on protein displacement from fresh and aged caseinate-stabilised soya oil emulsions was also investigated. Protein was displaced more readily at higher pH and, as with the β-casein-stabilised soya oil emulsions, ageing decreased the displacement of adsorbed protein.

Covalent Modification of Emulsified β-Casein Resulting from Lipid Peroxidation

Competitive displacement of adsorbed protein from emulsion droplets by the surfactant Tween 20 has been used to determine the influence of the oil phase and aging on the behavior of β-casein, the displaced protein being analyzed by reverse-phase high performance liquid chromatography HPLC. Unlike soluble β-casein or the protein displaced from tetradecane droplets where aging had no effect on the appearance of the HPLC profile, the protein displaced from a soya oil emulsion interface was observed to change. As the soya oil emulsion aged, the retention time of the protein decreased. Mass spectrometry of the modified protein showed that the molecular weight increased, indicating that some form of covalent modification was occurring. Gas chromatography–mass spectrometry of steam distillates of the samples showed the presence of a variety of aldehydes in microfluidized soya oil samples that were not present in either the original oil or the tetradecane emulsions. Aldehydes, particularly α,β-unsaturated aldehydes (enals), which are the major components formed in these soya oil emulsions, are known to react with nucleophilic amino acid side chains such as lysine. This is the probable cause of the observed modification of the emulsified protein. These aldehydes, whose concentration increased with storage time, are formed by peroxidation of the unsaturated fatty acyl chains present in the soya oil as a result of the microfluidization process used in the preparation of the emulsions. The tryptic peptide pattern also changed with age due to modification of the primary structure of the protein. Potential consequences of these chemical changes arising as a result of microfluidization are discussed.

Effects of Parenteral Application of Fish Oil versus Soy Oil Emulsions on Bacterial Clearance Functions

Background: The aim of this study was to test whether or not infusion of triglycerides containing ω-3 fatty acids (FAs) modifies immune function in terms of systemic clearance and organ distribution of injected Escherichia coli in a rabbit model. Materials and Methods: In groups of 6 rabbits each, a defined number of E. coli (1.3 × 10⁸ colony-forming units, CFU) was injected intravenously after 3 days of infusion with a lipid emulsion prepared from fish oil (Omegavenös^® 10%, 1.5 g/kg body weight/day), a soy oil preparation (Lipovenös^® 10%, 1.5 g/kg body weight/day), or after isotonic saline application (control). In order to compare dose-dependent effects, in a second experimental design a lower dose of each lipid emulsion (0.5 g/kg body weight) was infused over a 4-hour period before applicating E. coli . Parameters monitored were arterial pressure and rates of bacterial elimination from the blood. The animals were killed 3 h and 6 h after bacterial infection, respectively, and tissue samples of liver, spleen, lung, and kidney were collected for microbiological examinations. Results: Lipovenös infusion produced a significant delay in blood clearance compared with saline and Omegavenös treatment. The diminished systemic bacterial elimination after Lipovenös infusion was accompanied by increased numbers af viable bacteria in lung and spleen. In contrast to this, in the Omegavenös group bacterial counts in the lung did not increase and smaller amounts of viable bacteria were detected in organ homogenates 6 h after injection of E. coli . Conclusion: Compared with the soy oil preparation, ω-3 FAs induce improved bacterial clearance from the blood that is associated with significantly lower numbers of E. coli in the lung. Thus, appropriate nutrition providing ω-3 FA might serve as a pharmacological tool to improve host defence against bacterial infection in critically ill patients.

The Association of Lysozyme with Casein

The association of hen eggs’ lysozyme with caseins was studied by using three casein substrates: (I) solutions of the various caseins, (II) artificially made casein micelles of various compositions and (III) caseins adsorbed onto soya-oil emulsion droplets. In solution, lysozyme associated most strongly with αs-casein, less with β-casein and not with κ-casein. Accordingly, lysozyme associated less with casein micelles composed of β- and κ-casein (ratio 1 : 2) than with whole casein micelles, which contain αs-casein as well. The extent of association with emulsified caseins was in the order αs>β>κ, although the differences were not large. The effects of temperature and pH on the association appeared to be small. After association with caseins, lysozyme was always found to be active, suggesting that the active site of the molecule was not involved in the association. The association of lysozyme with casein-stabilized oil droplets may provide a satisfactory technique for immobilization of the enzyme on a liquid carrier, since in situ activity is retained.

Triglyceride hydrolysis of soy oil vs fish oil emulsions.

Fish oil triglycerides (TG) are being considered for use in IV lipid emulsions, but the characteristics of their lipase-mediated clearance from plasma are largely unknown. We compared the in vitro hydrolysis of soy oil long-chain triglyceride emulsions (LCT) and fish oil emulsions (omega-3) using lipoprotein (LPL) and hepatic (HL) lipases, omega-3 emulsions contained 18% and 28% of total TG fatty acid as eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), respectively. Under conditions of maximal hydrolysis, total free fatty acid (FFA) release was two- to threefold greater with LCT compared with omega-3 emulsions. Also, EPA and DHA together contributed proportionally much less than other fatty acids (< 20%) to FFA released from omega-3 emulsions. In mixtures of LCT emulsion with omega-3 emulsions, the presence of > 20% of omega-3 particles substantially inhibited LCT emulsion hydrolysis (by up to 50%). Our results suggest that, during infusion of omega-3 emulsions, EPA and DHA may enter cells as TG or partial glycerides within emulsion particles and not as FFA and that coinfusion of omega-3 emulsion with LCT emulsion at low omega-3:LCT emulsion ratios (up to 20% of total triglyceride as omega-3) will not substantially inhibit LCT hydrolysis.

Displacement of native and thiolated β-casein from oil—water interfaces—effect of heating, ageing and oil phase

Tetradecane- and soya oil-in-water emulsions stabilized by native and chemically thiolated β-casein were prepared using a microfluidizer. Displacement of adsorbed protein by addition of the non-ionic detergent Tween 20 after 2 and 28 days storage at 20°C, and before and after heating to 80°C for 30 min, was determined colorimetrically. Adsorbed protein was displaced more readily from the 2-day-old tetradecane emulsion than from the soya oil. Heating reduced displacement from the soya oil emulsion, but not from the tetradecane. Thiolated protein was displaced less readily than native β-casein. Storage decreased displacement of both forms of β-casein from the soya oil emulsions and heating had very little effect on the stability of the adsorbed protein in these aged emulsions.

Fish oil vs soy oil emulsion uptake and metabolism by cultured cells are substantially different

Fish oil vs soy oil emulsion uptake and metabolism by cultured cells are substantially different

Dietary fat composition influences fatty acid composition of milk fat globule membrane in lactating cows

Milk fat globule membranes are derived directly from the apical plasma membrane of mammary epithelial cells. To evaluate the effect of dietary fat on mammary membranes, we determined the fatty acid composition of the milk fat globule membrane in lactating dairy cows fed diets supplemented with fats of different fatty acid composition, or infused intravenously with soy oil emulsion. A preliminary survey, using an abbreviated preparation procedure (membranes isolated at 48,000 x g-max for 15 min), yielded about 45% of the total membrane fatty acids that could be recovered by centrifuging at the same speed for 120 min, and showed that changes in fatty acid composition of membranes reflected dietary fatty acids to some extent. Dietary palmitic acid increased the content of 16:0 in the membranes. A high corn diet increased ruminal formation of t18:1, and its level increased to 12% of membrane fatty acids. Infusion of soy oil emulsion increased 18:2 membrane content, and decreased the levels of 18:1 and 20:4. All treatments decreased the ratio of unsaturated/saturated fatty acids as compared to controls, whereas the ratio of polyunsaturated/saturated fatty acids was increased by feeding a high corn diet or by infusing soy oil. The ratio of 18:2/c18:1 increased from 0.31 to 1.0 after infusing soy oil for 4 days. The fatty acids of membranes isolated upon 120-min centrifugation were slightly more saturated. The differences were not sufficiently large, however, to affect overall results significantly.

Soya oil emulsion

Soya oil emulsion

Soya oil emulsion

Soya oil emulsion

The response to endotoxin in guinea pigs after intravenous black currant seed oil

The influence on the metabolic response to endotoxin of three days of total parenteral nutrition with lipids high in gammalinolenic acid (18:3 omega 6, GLA) compared to soy oil (SO) was examined in acute operatively stressed guinea pigs. GLA is the precursor of dihomogammalinolenic acid (DHLA), the substrate for synthesis of "1" series prostaglandins such as PGE1, which have previously been shown to be protective in endotoxin lung injury and traumatic shock. Guinea pigs fed an intravenous diet containing black currant seed oil (BCO) emulsion (20% GLA) or soy oil emulsion (0% GLA) for 2.5 days had their arterial pH, pCO2, pO2, and bicarbonate measured at baseline and hourly during a 7-hr infusion of endotoxin (lipopolysaccharide (LPS), 2mg/kg) or saline. Plasma lactate and fatty acid profile analyses were performed at the end of the LPS infusion. Increased levels of GLA and DHLA were present in the plasma phospholipid fraction of animals fed the black currant seed oil diet, while soy-fed animals had only trace amounts of GLA. In addition, the ratio of DHLA to arachidonate was higher in animals receiving the black currant seed oil total parenteral nutrition (TPN). After 2 hr of LPS infusion, all animals exhibited the typical shock response resulting in metabolic acidosis characterized by a significant (p less than 0.05) drop in pH from 7.34 +/- .02 (SO) and 7.39 +/- .02 (BCO) at baseline to 7.14 +/- .05 and 7.22 +/- .04 by 7 hr for SO and BCO groups, respectively. Plasma lactate values at the end of the infusion were significantly elevated compared to saline in both groups (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

424 INFLUENCE OF TOCOPHEROL VERSUS TOCOPHERYL ACETATE ON LIPID EMULSION ENHANCED LIPID PEROXIDATION IN NEWBORN RABBITS

We have previously shown that parenteral lipid emulsion increases expired volatile hydrocarbons, a sensitive index of in vivo lipid peroxidation. Newborn rabbit pups were randomly given 100 mg/kg of tocopherol (T), tocopheryl acetate (TA) or vehicle placebo (P) IV. Expired hydrocarbons were quantitated 18-24 hrs after initiation of soy oil emulsion infusion (3-4 g of fat/kg/24 hrs). Tissues were then obtained for analysis of thiobarbituric acid (TBA) reactants, T and TA content and glutathione peroxidase activity (GP). Expired ethane values were 3, 36 and 99 pmol/100 g body wt/min in the T, TA and P groups, respectively. Expired pentane values were 10, 61 and 179 pmol/100 g body wt/min in the T, TA and P groups. Ethane and pentane production was significantly different between groups (P<0.05). No differences were found in TBA reactants in blood and lung or lung GP activities. Liver TBA reactants were significantly different (P<0.05), 0.22, 0.35 and 0.70 nmol/mg tissue in the T, TA and P groups, respectively. Lung T levels were 79, 17 and 9 μg/g of tissue; and liver T levels were 393, 55 and 3 μg/g of tissue in the T, TA and P pups, respectively. From these data, we conclude that the extent of in vivo lipid peroxidation is proportional to the T content in tissue. Administration of TA results in significantly lower tissue T content and, therefore, less antioxidant activity against lipid emulsion enhanced lipid peroxidation.

Hemodynamic effects of intravenous 20% soy oil emulsion following coronary bypass surgery.

Because of its high caloric density, intravenous fat emulsions have been suggested as useful sources of calories and essential fatty acids in patients with serious heart disease in whom fluid restriction must be closely monitored. Previous studies in the experimental animal have suggested a myocardial depressant effect of intravenous fat emulsions at high infusion rates. In the present study, 19 adult patients, following uncomplicated isolated coronary artery bypass surgery, were divided into two groups. A constant infusion of 2 ml/min of soy oil emulsion (20% Intralipid) was administered to the first group. The second group received 20% Intralipid at 1 ml/min followed by a 2 ml/min infusion. In the group receiving the 2 ml/min infusion (averaging 5.25 mg/kg/min), significant decreases in cardiac output and increases in pulmonary capillary wedge pressure occurred. One patient suffered an adverse side effect which may have been related to myocardial ischemia. The second group of patients received an initial infusion of 1 ml/min (averaging 2.35 mg/kg/min) following which the rate was doubled. No significant hemodynamic changes or adverse side effects occurred in the second group. It is concluded that 20% soy oil emulsion can be administered safely to the recently postoperative cardiac surgical patient recovering from coronary bypass grafting, but the rate should not exceed the maximum clearance rate of 1 ml/min (2.67 mg/kg/min).

A Controlled Trial Using Intravenous Infusion of Soya Oil Emulsion in the Treatment of Children with Cystic Fibrosis

A controlled trial using intravenous infusions of soya emulsion in the treatment of children with cystic fibrosis. Five children with cystic fibrosis were given repeated intravenous infusions of soya oil emulsion (Intralipid) for 12 to 18 months and the effects on growth, health, sweat chloride and pancreatic enzyme activity compared with a control group. No beneficial effect was demonstrated and it is recommended that this form of therapy has no place in the routine treatment of children with cystic fibrosis. It is possible that treatment may have modified the degree of weight loss noted after 12 months of age. The lack of other beneficial effects and the problems involved in long-term Intralipid infusion should preclude the use of this form of therapy in the routine treatment of children with cystic fibrosis.

A Controlled Trial Using Intravenous Infusion of Soya Oil Emulsion in the Treatment of Children with Cystic Fibrosis

A controlled trial using intravenous infusions of soya emulsion in the treatment of children with cystic fibrosis. Five children with cystic fibrosis were given repeated intravenous infusions of soya oil emulsion (Intralipid) for 12 to 18 months and the effects on growth, health, sweat chloride and pancreatic enzyme activity compared with a control group. No beneficial effect was demonstrated and it is recommended that this form of therapy has no place in the routine treatment of children with cystic fibrosis. It is possible that treatment may have modified the degree of weight loss noted after 12 months of age. The lack of other beneficial effects and the problems involved in long-term Intralipid infusion should preclude the use of this form of therapy in the routine treatment of children with cystic fibrosis.

A Therapeutic Trial of Fatty Acid Supplementation in Cystic Fibrosis

Seven children with cystic fibrosis (CF) have been treated for at least one year with intravenously administered soya oil emulsion. In all, an improvement of at least one biochemical abnormality in character with the disease appeared. The children's clinical course remains benign. This course is remarkably better than that of other children with CF treated without Intralipid in Auckland in the same period, though a placebo effect cannot be discounted. It is postulated that intravenous supplementation with essential fatty acid in CF may in turn partially correct an error of metabolism of prostaglandins present in the disease.

Unusual clinical course in a child with cystic fibrosis treated with fat emulsion.

A child diagnosed as having cystic fibrosis by customary criteria has been given regular parenteral soya oil emulsion from near birht. Sweat tests have improved, pancreatic achylia was relieved, and the child at present remains entirely well. Correction of the essential fatty acid deficiency found in cystic fibrosis may prevent some of the manifestations of the disease.