Glyceride Fraction Research Articles

Fat transport in the locust

When fat-body tissue from locusts was incubated with palmitate-1-C14 in phosphate-saline, the acid was readily taken up by the tissue; 80–90% of that taken up was esterified and recovered in the glyceride fraction. When the prelabeled tissue was incubated in hemolymph, glycerides were released from the tissue into the medium. The effect of hemolymph was specific; glycerides were not released into phosphate-saline, bovine serum, or buffered solutions of bovine serum albumin or egg albumin. The release of glycerides was inhibited by fluoride and by cyanide. The amount of glyceride released was proportional to the amount of hemolymph that was added. Effectiveness of the hemolymph in this regard was not affected by prolonged dialysis, but was destroyed by heating. The specific activity of the glycerides released was at least 10 times higher than the average specific activity of the glycerides inside the tissue. A considerable fraction of the released glycerides was incorporated into the lipoprotein fraction of the hemolymph. Uptake of glycerides by fat-body tissue was also demonstrated.

Plasma and liver lipids of ethionine-treated rats.

AbstractThe changes in liver and plasma lipid concentrations caused by ethionine have been studied in the rat. A dose‐response curve was obtained for one time interval. For a constant dosage the time response curve was measured. The response of rats of different sex and nutritional state was also studied. Ethionine caused a rise in liver lipids, essentially confined to the glyceride fraction, a fall of plasma phospholipids, cholesterol esters, free cholesterol and glycerides and a rise of plasma free fatty acids (FFA). The liver lipids rose to a higher level in fasted female than in fasted male rats. Male rats also required a higher dose of ethionine for maximal response. Carbohydrate feeding to otherwise fasted female rats diminished, but did not abolish, the liver fat accumulation. The changes in plasma and liver lipid levels were maximal 24 hours after the ethionine administration. At 72 hours the liver lipids had fallen again almost to the zero time value. During the recovery phase the plasma glycerides rose above the zero time value and at 72 hours were 3 times higher.

The in vitro incorporation of acetate- 1 -C14 into normal and leukemic leukocyte lipids

SUMMARY White blood cells and plasma from normal and leukemic subjects were incubated in the presence of acetate-1-C. The distribution of radioactivity in six lipid fractions of cells and plasma was measured. Leukemic leukocytes incorporated the highest percentage of radioactivity into the phospholipid fractions whereas normal leukocytes incorporated the highest percentage inta the glyceride fractions. There is no conclusive evidence that the differential white cell count had an influence on these observations. The difference may be related to a more active lipid metabolism in leukemic cells.

Connective tissue. VI. Dermal lipid response to diphenylhydantoin.

Summary and conclusionsDilantin decreased significantly the dermal concentration of neutral glycerides, total lipids and phospholipids in rats. This loss of neutral glycerides from dermal tissue was associated with a decrease in the percentage of di-glycerides found in the neutral glyceride fraction of the skin.

Lipid Components of the Fat-Globule Membrane

Summary Lipid components were extracted from fat-globule membranes prepared by two procedures. One method (Scheme I) started with cold, pooled milk, whereas in the other procedure (Scheme II) freshly drawn, uncooled milk served as the source. The lipids obtained were resolved by gradient elution from a silicic acid chromatographic column. The following lipid classes were identified as components of the fat-globule membrane: carotenoids, a squalene-like compound, cholesterol esters, cholesterol, a unique triglyceride mixture similar to the high-melting glyceride fraction, mono-diglycerides, phospholipids and, from some preparations, unesterified fatty acids. The minor differences in composition between the membrane lipids reflected the age of the milk and the method of preparation. Membranes isolated from the pooled milk by Scheme I contained lower concentrations of phospholipids and associated proteins. Carotenoids, cholesterol esters, and the squalene-like component were removed from the membranes by washing with ethyl ether.

Physical properties of milk fat: II. Some factors influencing crystallization

SummaryThe crystal habit of milk fat is determined by the cooling procedure employed and is changed markedly by interesterification (randomization) of the fat. X-ray diffraction analysis indicated that slowly cooled milk fat occurs in both beta prime and beta modifications, whereas in rapidly cooled milk fat, evidence for the beta prime modification only was obtained. The long spacing was greatly increased by interesterification, especially when the fat was slowly cooled. The presence or absence of certain high melting glyceride fractions greatly influenced solid fat content, softening point and hardness of milk fat.

Characteristics of High-Melting Triglyceride Fractions from the Fat-Globule Membrane and Butter Oil of Bovine Milk

Summary A high-melting triglyceride fraction (HMGF) was isolated from an alcohol-ether extract of the fat-globule membrane and from an ethanol extract of butter oil. The HMGF was characterized by its iodine value (4.8-5.0), saponification equivalent (200-202), and melting range (50.0-52.5° C.), and by its ultraviolet (220-340m μ ), near-infrared (1.6-3.1 μ ), and infrared (2-14 μ ) spectra. The fatty acid composition of the fraction was determined by converting the glyceride to its constituent fatty acid methyl esters which were resolved by gas chromatography as follows: C 10 −0.1, C 12 −0.9, C 14 −11.0, C 10 −59.6, C 18 −16.5, C 18 1= −5.6, C 18 2= −0.4, C 18 3= −0.2, and unassigned components—5.8 mole %, respectively. Characteristics of the high-melting glyceride fractions obtained from the membrane and from butter oil were similar. The HMGF constitutes the triglyceride content of the membrane.

Distribution of C14 in rats after intravenous injection of non-esterified palmitic acid-1-C14.

Abstract.The metabolism of non‐esterified fatty acids in the plasma was studied by investigating the distribution of intravenously injected non‐esterified palmitic acid‐1‐C14 in rats. Lipids from different organs were studied for activity directly or after separation by means of chromatography on silicic acid columns. The bulk of the activity was found to be taken up by the liver and muscle tissue. A minor fraction was recovered in the fat depots. The results suggested that the fat depots might take up non‐esterified fatty acids from plasma without simultaneous esterification. A fair proportion of the palmitic acid was retransported in the plasma glyceride fraction after esterification, probably in the liver.

The High-Melting Glyceride Fraction from Milk Fat

The High-Melting Glyceride Fraction from Milk Fat

Effect of Fat in Diet on Unsaturated Fatty Acids in Phospholipid, Cholesterol Ester and Glyceride Fractions in Serum of Dogs

Effect of Fat in Diet on Unsaturated Fatty Acids in Phospholipid, Cholesterol Ester and Glyceride Fractions in Serum of Dogs

The component acids and glycerides of Erythrina indica seed fat

AbstractThe glyceride structure of Erythrina indica seed fat has been studied by crystallization of the neutral fat from acetone and ether. The composition of each of these glyceride fractions was studied by the usual ester‐fractionation method, using an electrically heated and packed column for fractional distillation under high vacuum, and the final probable glyceride structure computed therefrom. The chief component acids are palmitic (8.2%), stearic (8.0%), arachidic (4.3%), behenic (13.3%), hexadecenoic (3.1%), oleic (45.6%), linoleic (7.1%) and eicosenoic (9.8%) acids together with a minor amount of lignoceric acid (0.6%). The component glycerides consist of (1) 10.1% mono‐unsaturated‐disaturated, (ii) 79.4% di‐unsaturated‐monosaturated and (iii) 10.5% tri‐unsaturated glycerides.

The component acids and glycerides of areca‐nut (areca catechu) fat

AbstractThe fatty acid composition of areca‐nut fat was determined by the usual ester‐fractionation method, using an electrically heated and packed column for fractional distillation under high vacuum (0.2 mm.). The glyceride structure was studied by crystallization of the neutral fat from acetone and ether; the composition of each of these glyceride fractions was studied by the fractionation method and the final possible glyceride composition computed therefrom. The chief component acids are lauric (19.5%), myristic (46.2%) and palmitic (12.7%), and in the unsaturated portion oleic (6.2%), linoleic (5.4%) and hexadecenoic acid (7.2%). Minor proportions of stearic, decanoic and of unsaturated monoethylenic C12 and C14 acids are also present. The chief component glycerides are (i) 56% of fully saturated (trimyristin, dimyristins and lauromyristopalmitin); (ii) 30% of mono‐unsaturated‐disaturated (mainly hexadecenolauromyristin, with some oleo‐(linoleo)myristopalmitins and dimyristins); (iii) 14% of diunsaturated‐monosaturated (oleolinoleoglycerides, mostly oleolinoleopalmitin). The glyceride composition follows closely Hilditch's rule of widest distribution of acyl radicals in the glyceride molecules. The fully saturated glyceride content of the fat, determined separately by the method of Hilditch & Lea,1 is 53.7%. The fully saturated components are found to contain (by the fractionation method) : 19.4% of lauric, 54.6% of myristic, 19.2% of palmitic and 6.8% of stearic acids. The proportions of various acids in the fully saturated components are similar to the corresponding ones in the saturated acid portion of the whole fat.

Further studies on lipotropism in the domestic duck (White Pekin).

On choline-free diets containing 10, 18, and 28% casein, the total liver lipids of ducklings were found to be 34.8, 25.0, and 13.8% respectively. Supplementation of the 10% casein diet with 0.5% methionine increased the liver lipids. The same amino acid has no effect at the intermediate level of casein while it is lipotropic at the 28% casein level. In similar experiments with a purified soybean protein (low in methionine) fed at levels of 12, 21.7, and 27.9%, the liver lipids were 31.8, 26.6, and 27.6% respectively. These values do not differ significantly from each other. Methionine was found to be lipotropic at any of these three levels of soybean protein, and more so as the level of the soybean protein increased in the diet. From these results, it is concluded that the purified soybean protein used is a nonlipotropic protein, while casein is definitely lipotropic in ducklings. The lipotropic activity of methionine is closely related to the quality and quantity of the protein in the diet. On high fat diets containing 22, 32, and 42% fat, choline had no lipotropic effect. The average liver lipids for all groups ranged from 11 to 15%. High fat diets are less inducive of fatty livers than high carbohydrate diets. Ducklings fed a fat-free, choline-free basal diet presented livers with an average total lipids of 18%. Supplementing the basal diet with 1% cholesterol increased the liver lipids to 22%. Inositol is lipotropic either in the presence or absence of cholesterol, but choline was much more effective under similar conditions. The two lipotropic factors have a synergistic action and the reduction of the liver lipids is primarily on the glyceride fraction. Cholesteryl ester was at its lowest value in the group fed the basal diet supplemented with inositol only.

Modification of vegetable oils. IX. Purification of technical monoglycerides

SummaryMethods of purifying technical monoglycerides produced from cottonseed oil stearine by interesterification were investigated.It was found that the concentration of uncombined glycerol in technical monoglycerides could be reduced to about 0.4% by dissolving the technical product in commercial hexane, adding water equivalent to twice the amount of free glycerol, and separating the hexane solution. The formation of stable emulsions was largely avoided by this procedure.Technical monoglycerides containing 38.9% monoglycerides were purified by distributing them between two immiscible liquid phases (commercial hexane and an aqueous solution of methanol or ethanol). Products containing as much as 80% of monoglycerides were obtained in this manner.On fractionally crystallizing a solution of the same technical monoglyceride from aqueous ethanol, a glyceride fraction having a purity of 92% and containing 74% of the monoglycerides in the technical product was obtained.It was found that by addition of proper amounts of water ethanol, isopropanol, methanol, and acetone could be made nearly equivalent for fractionating mixtures of glycerides. Methanol is most sensitive to a change in water content while isopropanol is least sensitive.When commercial hexane was used in the fractional crystallization of technical monoglycerides, as much as 84% of the non‐monoglycerides was retained in the liquid phase, and the glycerides from this phase were found to have a monoglyceride content of 9.8%. The solids obtained by crystallizations from hexane were found to simulate the filtrates obtained with the polar solvents.When a mixture of technical monoglycerides was partially crystallized from a solvent, the composition of the glycerides remaining in the solvent was relatively unaffected by changes in the concentration of the glycerides originally present in the solution.

BIOCHEMICAL ASPECTS OF MAMMARY GLAND FUNCTION

BIOCHEMICAL ASPECTS OF MAMMARY GLAND FUNCTION

Low‐temperature solvent fractionation of corn oil and calculation of its glyceride structure

SummaryCorn oil was subjected to a low‐temperature solventfractionation process and separated into 19 glyceride fractions; the glyceride structures of the fractions were calculated and added to obtain the glyceride structure of the oil. The experimentally obtained glyceride structure was compared to the structures calculated according to the mono‐acid triglyceride, random, even, and partial random schemes and was found to agree most closely with the partial random system.

The Fatty-Acid Composition of Glyceride Fractions Separated from Milk Fat

Summary 1.Milk fat, separated into five different fractions by precipitation from a solvent at low temperatures, was analyzed by the ester-fractionation method to determine the amount and distribution of the individual fatty-acids. 2.The amounts of each fatty acid present in each fraction and in the milk fat have been determined. These values, together with corresponding weight and mol percentages, are presented. 3.When the values for the composition of the original milk fat are compared with those obtained by reconstructing milk fat from the increments of the individual fatty acids contained in the fractions, an excellent agreement is observed. These data also compare favorably with those reported by others. 4.The occurrence of small quantities of individual fatty acids is detected 5.with more reliability from the fractions than from the complex entire fat.