Comparative study of the molecular species of chloropropanediol diesters and triacylglycerols in milk fat

In an effort to establish the origin of the fatty acid esters of 3-chloropropanediol, which recently have been isolated in small amounts from goat milk, we compared the molecular species composition of the chlorohydrin diesters and of goat milk triacylglycerols. The chloropropanediol diesters were found to be composed of molecular species containing C₁₀−C₁₈ fatty acids and corresponded closely in carbon number to those calculated for the long chain sn-1,2-diacyl-glycerol moieties of goat milk triacylglycerols. The molecular species of goat milk total triacylglycerols contained C₄−C₁₈ fatty acids. It is suggested that triacylglycerols and chloropropanediol diesters are derived from the same pool of long chain fatty acids. A molecular distillate of bovine milk fat did not contain chloropropanediol diesters, while the available samples of human milk fat were shown to contain alkyldiacylglycerols as the major components of a neutral lipid fraction corresponding in polarity to the chloropropanediol diesters.     

Fatty acid composition of polar lipids in goats' milk

Silicic acid column chromatography was used to separate the polar lipids of goats' milk into glycolipid, phosphatidylethanolamine, phosphatidylserine plus phosphatidylinositol, phosphatidylcholine, and sphingomyelin fractions. Each fraction was purified by column chromatography and its fatty acid profile determined by gas liquid chromatography and mass spectrometry. The glycerophospholipids each contained 18∶1 as the predominant fatty acid (∼45%). The sphingolipids contained a high percentage of long-chain saturated fatty acids (C₂₂ to C₂₄>45%); the glycolipid fraction also contained ca. 2% 2-hydroxy fatty acids. The data represent a comprehensive cross-sectional study of the major polar lipids found in goats' milks.     

Composition of milks of dairy cattle. I. Protein, lactose, and fat contents and distribution of protein fraction.

Milks from commercial dairy herds in Southeastern Pennsylvania were analyzed for total protein, casein, whey protein, beta-lactoglobulin, nonprotein nitrogen, and lactose contents. Data for fat contents and milk yields were from Dairy Herd Improvement Association records for the same lactation. Milk samples were from a single milking of healthy cows (151) in midlactation. Since the remainder of the milk was returned to the bulk milk of the farm, the data represent market milk composition. The data were grouped and analyzed by breed and beta-lactoglobulin phenotype; there were 18 to 33 cows per breed. In true protein percentage, the breeds ranked: Jersey 4.07 plus or minus .49, Brown Swiss 3.84 plus or minus .47, Guernsey 3.56 plus or minus .53, Ayrshire 3.30 plus or minus .52, Milking Shorthorn 3.17 plus or minus .47, Holstein 3.07 plus or minus .43. Breeds differed in all other components and in milk yield. Brown Swiss ranked highest in yield of protein. Only whey protein and beta-lactoglobulin contents were influenced by the beta-lactoglobulin genotype with beta-lactoglobulin A greater than AB greater than B in whey protein content.     

Stereospecific analysis of fatty acid esters of chloropropanediol isolated from fresh goat milk

The fatty acid esters of chloropropanediol isolated from goat milk fat in small quantities were subjected to a stereospecific analysis via phospholipase C and phosphocholine esters as intermediates. Synthetic rac-1-chloro-2,3-dioleoyl-propanediol was prepared by standard methods and was used as a control. The stereospecific analyses were performed following a release of the fatty acids from the primary positions of each chloropropanediol diester with pancreatic lipase. The resulting X-1-chloro-2-acylpropanediols were then converted into the corresponding phosphocholine derivatives by a stepwise reaction with phosphorus oxychloride and choline chloride. The X-1-chloro-2-acyl-3-phosphocholinepropanediols were subjected to hydrolysis with phospholipase C (C. perfringens), which hydrolyzed 50% of the phosphatide within two min and the rest of it in two hr. From previous experience with glycerol esters, it was assumed that the more rapidly hydrolyzed molecules were the sn-1-chloro-2-acyl-propanediol derivatives and the more slowly hydrolyzed ones the sn-2-acyl-3-chloropropanediol derivatives. A hydrolysis with phospholipase A₂ (Crotalus adamanteus) released 50% of the total fatty acid along with the corresponding lyso compound within 10 min, after which there was no further reaction. The hydrolysis products were assayed directly by gas liquid chromatography (GLC) or were isolated by thin layer chromatography (TLC) prior to quantitation by GLC. Both naturally occurring and synthetic chloropropanediol diesters behaved similarly on stereospecific analysis and were therefore concluded to be racemic.     

Paraffinic hydrocarbon composition of earthworms (Lumbricus terrestris)

The paraffinic hydrocarbon fraction of the lipids extracted from earthworms (Lumbricus terrestris) contains ca. 88%n-alkanes and 12% branched alkanes and other hydrocarbons. Then-alkanes range from C₁₃ through C₃₃, and their most interesting feature is the even-over-odd carbon number predominance in the C₁₃−C₂₄ range. The nonnormal hydrocarbons consist primarily of monomethyl-substituted alkanes. Other hydrocarbons that have been identified include the C₁₆. C₁₈, C₁₉ and C₂₀ isoprenoids and the C₁₈, C₂₀ and C₂₂ n-alkylcyclohexanes.     

Composition of the milks of dairy cattle. II. Ash, calcium, magnesium, and phosphorus.

Milks from commercial dairy herds in Southeastern Pennsylvania were analyzed for ash, calcium, magnesium, and phosphorus. Milk samples were from single milkings of 151 healthy purebred cows in midlactation. The data represent market milk composition. Average values for all animals were ash .78%, calcium 1.25 g/liter, magnesium .11 g/liter, and phosphorus 1.14 g/liter. The data also were grouped and analyzed by breed and beta-lactoglobulin phenotype. Breeds differed in all inorganic components with 18 to 33 cows per breed. No differences in ash, calcium, magnesium, or phosphorus were significant when the data were grouped by beta-lactoglobulin phenotype.     

Composition and Distribution of Lipids of Goats’ Milk

Fresh commercial goats’ milks were examined for their lipid contents and distribution of these lipids among milk fractions. Whole milk, skim milk (produced by centrifugation at 330 and 2,000 × g), and cream were studied. Petroleum ether (free lipids) and chloroform methanol (2:1) (bound lipids) were used successively to extract the lipids from all milk fractions. Average total lipid content for five bulk milk samples was 5.0 ± 1.2%. Lipid fractions of whole milk and cream contained 97 to 99% free lipid and 1 to 3% bound lipid, respectively. Free lipid was 96.8% triglyceride, whereas bound lipids contained neutral lipid, glycolipid, and phospholipid. In this respect, goats’ milk resembled cows’ milk. However, goats’ skim milk fractions contained significantly more free lipid than did cows’ milk. This free lipid, investigated in detail by gas chromatography, was shown similar in triglyceride distribution and fatty acid content to whole goats’ milk triglyceride. Quantitative data for the triglyceride distribution in all fractions are given and differ from published data for fresh goats’ milk.     

The composition of bloom fat in chocolate

Summary The composition of the fat which has bloomed in chocolate has been investigated. There is evidence that the type of center which is coated with chocolate has no effect upon the fatty-acid composition of the bloom fat. The rate of blooming however was found to be affected by the center. The theory that the oils in coated nuts migrate to the chocolate surface to cause fat bloom has been disproved. Comparison of the fatty acids present in the bloom fat with respect to the coating fat show a decrease in the unsaturated acids and an increase in the saturated acids. There is evidence that hydroxyl containing oxidation products of the fatty materials in the chocolate are not present in the migrated fat. Formerly with Stephen F. Whitman and Sons Company, Philadelphia, Pa., Mr. Cerbulis is now with the Eastern Utilization Research and Development Division, Philadelphia, Pa. Mr. Clay is a private consultant with offices in Wynnewood, Pa.     

Neutral lipid and fatty acid composition of earthworms (Lumbricus terrestris)

Earthworms (Lumbricus terrestris) were extracted with chloroform-methanol (2∶1) and examined primarily for neutral lipids and fatty acids. TLC showed spots for sterols, hydrocarbons, free fatty acids, phospholipids and pigments but none for glycerides (tri-, di- or mono). Saponification of the crude lipid extract yielded 32% fatty acids, 25% unsaponifiables and 43% unidentified. The lipid contained 3% hydrocarbon and 16% sterols. GLC of the hydrocarbons showed at least 13 components. GLC of the sterol fraction showed peaks corresponding to cholesterol (the major component), γ-sitosterol, β-sitosterol, stigmasterol, campesterol, and ergosterol. GLC showed that at least 38 fatty acids were present, with 18∶1, 18∶2, 18∶0, 20∶1 and 17∶0 predominanting. Abstracted in part from the Ph.D. dissertation of J. Cerbulis, Rutgers, The State University, 1966.