Synthetic Triglyceride Research Articles

Raman spectroscopy of the milk globule membrane and triglycerides

The acyl chain mobilities of the lipids of bovine milk fat globules and the component triglycerides have been determined by Raman spectroscopy as a function of temperature from -100°C to 80°C. A broad transition is observed centered about 2–6°C. The C-H and C-C stretching bands in the spectra of liquid and crystalline triglycerides are used comparatively to show that the lipids of the milk globule membrane are 30–40% more ordered than the lipids of the intact milk fat globules at 20°C. Synthetic triglyceride melts, quenched rapidly, are used to illustrate the effect of the thermal history of a sample on lipid order as determined spectroscopically. Strong infrared amide I and amide II bands at 1646 and 1543 cm −1, respectively, indicate that the protein conformation of the globule membrane is not characterized by extensive regions of beta-sheet structure. Raman spectra of the globule triglycerides indicate cis unsaturation of 39 ± 5% by comparison to triolein and trielaidin.

Hypocholesterolaemia in the rat after [formula omitted] acid (CPIB) administration as a synthetic triglyceride, 1,3-dipalmitoyl [formula omitted

A synthetic triglyceride analogue, 1,3-dipalmitoyl 2(p- chlorophenoxyisobutyroyl)-rac- glycerol , was fed to rats and its effect compared to that of clofibrate. Both compounds significantly lowered plasma cholesterol concentration and the decreases essentially paralleled each other, even when the dose of drug or the period of administration was varied. No consistent effect was noted on the plasma triglyceride concentration. The results suggest that synthetic lipids are potentially suitable carriers for the oral administration of pharmacologically active agents.

Staphylococcal lipases.

AbstractA lipase rich fraction was isolated from the cell free supernatant of 24 hr broth culture ofStaphylococcus aureus B‐120, grown in trypticase soy broth at 37 C. Lipase from the cell free supernatant was precipitated with equal volumes of absolute ethanol. This fraction was purified further by differential precipitation at pH 8.6 and 4.3. Subsequent purification, using Sephadex G‐200 and BioGel 300, yielded a preparation with 350–450‐fold increase in specific activity. The purified lipase had an optimum pH of 8.5 at 37 C. The electrophoretic mobility was‐7.78×10−5 cm2/volt/sec. The sedimentation coefficient for the two peaks was 2.85 and 8.5, respectively, and the mol wt was 100,000. The purified lipase hydrolyzed a variety of natural oils and fats. The amount of free fatty acids liberated from hydrogenated soybean oil (iodine value<3) was one‐third compared to natural oils and fats. Gas chromatographic analysis of hydrolyzed synthetic triglyceride, with palmitic, stearic, and oleic acids at the rac 1, 2, and 3 positions, respectively, indicated that the enzyme was capable of hydrolyzing the glycerolfatty acid bonds at all three positions. The yield was 40% palmitic, 20% stearic, and 39% oleic acids. Formaldehyde, mercaptoethanol, cysteine, glutathione, and terramycin had inhibitory effects upon lipase activity while hydrogen peroxide, streptomycin, and sodium taurocholate had a stimulatory effect upon the activity.

Kinetics of lipoprotein lipase activity: Effects of the substrate apoprotein on reaction velocity

1. In the absence of the substrate lipoprotein protein moiety, lipoprotein lipase activity with synthetic triglyceride and partial glyceride substrates was under control of ionisable groups, with p K values of 6.8 and 9.1. The enthalpy of ionisation of the former was 5500 cal/mole. Reaction of an ionisable group with p K = 8.0 was also indicated. 2. The incorporation of delipidated very low density lipoprotein protein with the lipid substrate increased the maximal reaction velocity of lipase activity at all hydrogen ion concentrations, and also decreased the apparent Michaelis constant of the reaction at alkaline pH. 3. Lipoprotein protein also induced a shift in the alkaline limb of the plot of maximal reaction velocity vs pH, and apparent Michaelis constant vs pH, p K values in the presence of cofactor protein were 7.0 and 9.8 with indicated reaction also of a group with p K = 8.8. 4. Similar p K values were obtained with lipoprotein lipase purified from post-heparin plasma, and from adipose tissue.

Migration of additives from plastics films into edible oils and fat simulants

The migration of two different additives from high-density polyethylene (HD-PE), from polyvinyl chloride (PVC) and from polystyrene (PS) into edible oils and fat simulants has been investigated using the radiotracer technique and contact times of 60 days at 20°C and 5 hr at 65°C. The 14C-labelled plastics additives used were Ionox 330 (1,3,5-trimethyl-2,4,6-tris-(3,5-di- tert-butyl-4-hydroxybenzyl[ 14C])benzene), Advastab (now Irgastab) 17 MOK (di- n-octyl[1- 14C]-tin-2-ethyl- n-hexyl dithioglycollate), stearic acid[1- 14C]amide and n-butyl stearate[1- 14C]. The edible oils used were Biskin (a partially hydrogenated groundnut oil), coconut oil, sunflowerseed oil, olive oil and butter. Synthetic triglycerides and organic solvents such as alkanes, di- n-alkyl ethers, methanol and paraffin oil were used as fat simulants. The measurements showed organic solvents to be unsuitable as general fat simulants. The migration values of an additive from a plastics film into different edible oils were so similar that one edible oil could serve as a simulant for all others. However, the presence of other naturally-occurring substances makes the analytical determination of migrated additives in edible oils very difficult, so a synthetic triglyceride mixture with extraction properties similar to those of coconut oil was developed to serve as a standard fat simulant. Analytical studies with this fat simulant, HB 307, proved its advantages over coconut oil. Its suitability as a standard fat simulant was confirmed in migration tests.

DETERMINATION OF TRIGLYCERIDE STRUCTURE VIA SILVER NITRATE-TLC.

AbstractA procedure for the quantitative analysis of component triglycerides by thin‐layer chromatography (TLC) with silver nitrate‐silicic acid coated plates in combination with lipase hydrolysis is described. The method is demonstrated on synthetic triglyceride mixtures and applied to several natural fats.The results indicate that the fatty acids of natural fats are not distributed among the triglycerides in accordance with any simple mathematical formula and methods based on mathematical distribution patterns cannot be generally applied.

Biosynthesis of fatty acids and cholesterol as related to diet fat

The objective of this study was to explore the influence of a series of simple triglycerides and natural fats on cholesterogenesis and lipogenesis. Male rats were given a partially synthetic diet containing no added fat or 30% of tributyrin, tricaproin, tricaprylin, tricaprin, trilaurin, trimyristin, tripalmitin, triolein, trilinolein, lard, butter oil, safflower oil, or a synthetic triglyceride made of one part palmitic and two parts oleic acids. After 2 weeks, the rats were administered 0.2 mc. acetate-1-C 14/kg. of body weight (intraperitoneally) and were sacrificed 1 hr. later. Various tissues were removed for analysis. When compared to the low fat diet, all of the non-linoleic acid diet fats caused increases in liver 16:1 and 18:1 acids at the expense of the polyene acids, mainly 18:2 and 20:4. Stearic acid was also reduced in all cases except after tricaprin and triolein. In addition to the above, the tripalmitin diet compensated for a pronounced loss in the polyunsaturated acids with an increase in the 16:0 and 18:0 acids. Unexpectedly, dietary laurate was not deposited in the liver but resulted in a larger increase in liver myristate than after the ingestion of myristate itself. The animals on the low fat diet incorporated over 7% of the labeled acetate into liver fatty acids, those on the short-chain fat diet about 5%, those on the medium chain length fat diet 2.5%, those on the longer chain length saturated fat diet 1.5%, and those on the safflower oil and trilinolein diets only 0.3 and 0.2%, respectively. During the ingestion of the short-chain fatty acids, a very high level of palmitic acid synthesis occurred, suggesting that the short-chain acids do not inhibit its synthesis and are themselves converted to palmitic to a significant degree. During the ingestion of the long-chain fatty acids, all synthesis of fatty acids was strongly inhibited. In all cases there was a lower degree of incorporation of acetate into oleic than into palmitic. The concentration of liver cholesterol was only 2.3 mg./g. in animals on the low fat diet, approximately 4–5 mg./g. in animals on the saturated triglyceride diets, about 6 mg./g. in those on the triolein diet, and above 7 mg./g. in those on the trilinolein diet. However, only tripalmitin ingestion increased the level of liver cholesterol synthesis, as measured by the percentage of injected labeled acetate incorporated. Two weeks of dietary tripalmitin sharply decreased the amount of newly synthesized cholesterol transported into the aorta during the first hour after labeled acetate injection.

Dog Serum Lipid Responses to Dietary Fats Differing in the Chain Length of the Saturated Fatty Acids

Fats of similar composition in terms of saturated, monoene, and polyene fatty acids, but differing in the chain length of the saturated fatty acids, were given alternately to groups of dogs at a level of 40% of the total calorie intake for periods of two weeks. Each experiment also included two control periods before and after the administration of the experimental fats, in which a low-fat diet containing 4% of fat calories was given. The glycerides of saturated fatty acids of 12- and 14-carbon atoms produced significantly higher serum cholesterol and phospholipid values than either the glycerides of 16- and 18-carbon saturated fatty acids or of 8- and 10-saturated fatty acids. When compared with the low-fat diet the experimental diets produced the following mean increases of serum cholesterol concentration (in mg per 100 ml ± SE of the mean): coconut oil, 146 ± 12.0; 12C mixture (60% of coconut oil, 40% of olive oil), 137 ± 9.9; 18C mixture (80% oleostock, 20% of totally hydrogenated corn oil), 76 ± 7.9; MCT mixture (a synthetic triglyceride containing mainly saturated fatty acids of 8- and 10-carbon atoms with 6% of olive oil and 2% of safflower oil), 21 ± 8.4. The serum phospholipid changes were parallel to those of cholesterol. The cholesterol levels produced by the glycerides of saturated fatty acids of 8- and 10-carbon atoms were similar to those produced in the dog by oils rich in polyunsaturated fatty acids (sunflower oil) given at the same proportion of the total calories.

Interesterification reactions of triglycerides

A study of the interesterification reaction has been undertaken using synthetic triglyceride systems (triolein in varying proportions with tripalmitin) and also combinations of lard and hydrogenated lard. An empirical crystallization method has been used in determining the amount of trisaturated glycerides present in a mixed fat. The results indicate that the end-products of interesterification approach the composition expected from the principle of random distribution.