Fractionation animal fats

Petrol ether-diethyl ether (95 + 5) is especially suitable for chromatography of vegetable and animal waxes on siHca gel G. The solvent petrol ether-diethyl ether-acetic acid (90 + 10 + 1) has been that mostly used in the TLC of lipids. It is particularly suitable for fractionating animal fats (Figs. 131 and 135). Vegetable oils which contain epoxy-and hydroxy-compounds are chromatographed with mixtures of petrol ether-diethyl... 

To summarise, a fractionation step allows the isolation of the compounds of interest from the other molecular constituents, particularly from the fatty acids that are well-ionised. To compensate for the low ionisation yield of some compounds, such as TAGs, the solutions may be doped with a cation. Samples are then directly infused into the ion electrospray source of the mass spectrometer. A first spectrum provides an overview of the main molecular compounds present in the solution based on the peaks related to molecular cations. The MS/MS experiment is then performed to elucidate the structure of each high molecular compound. Table 4.2 shows the different methods of sample preparation and analysis of nonvolatile compounds as esters and TAGs from reference beeswax, animal fats and archaeological samples. 

To obtain substantial yields of surfactant hydrophobes, especially in the most useful C12— 14 range, the choice is restricted to coconut, palm and palm kernel oils. In the C16-18 range, the same oils are also used but animal (normally beef) tallow can be used. The use of animal fats raises some ethical issues but these are not commonly used to produce anionic surfactants. The oils may be converted to methyl esters by transesterification which allows easier distillation to remove heavy/light fractions and the esters are finally hydrogenated to fatty alcohols. Alternatively, the fat or oil can be hydrolysed to fatty acid prior to esterification... 

Sometimes the question asked is whether animal fat is absent from products such as cosmetics or from some other oleochemical product prepared from fats. This can include products such as emulsifiers. Where the product contains original triglyceride then this portion can be considered as described above, and the absence of cholesterol can be considered as good evidence that animal fats are absent. This, however, does not apply to triglycerides formed after saponification of fatty acids, followed by fractionation and recombination with glycerol. So-called fractionated coconut oil is manufactured by this process, and any similar product made from fatty acids from an animal source would not show the presence of any cholesterol. Similarly other oleochemicals formed from fatty acids derived from animal fats would also not contain cholesterol. In these cases it is often impossible to detect the presence of animal fat by testing for cholesterol. The only possibility in some cases might be to look at... 

Standards for named animal fats and named vegetable oils These standards were adopted formally by the CAC in 1999 (Joint FAO/WHO, 1999e). The Standard for Named Animal Fats combines and updates provisions for lard, rendered pork fat, premier jus and edible tallow. The Named Vegetable Oils Standard covers 15 different oils of particular importance in international trade and also the palm oil fractions, palm olein and palm stearin (see Table 8.5). 

The unsaponifiable fraction of fats consists of sterols, terpenic alcohols, aliphatic alcohols, squalene, and hydrocarbons. The distribution of the various components of the unsaponifiable fraction in some fats and oils is given in Table 2-19. In most fats the major components of the unsaponifiable fraction are sterols. Animal fats contain cholesterol... 

Sterols Sterols are quantitatively the most important components of the unsaponifiable fraction of vegetable oils and animal fats (Figure 7). 

Animal fats, such as milkfat, tallow, and fish oils, are characterized by the exclusive presence of cholesterol, whereas the sterol fraction in vegetable oils consist of a wide group of compounds also known as phytosterols. 

One common feature of the mediterranean dietary habit is the use of olive oil as fat source in place of animal fat typical of Northern European and USA diets. As compared to other vegetable oils, olive oil is charaeterized by the peculiar composition of the tryglieeride fraction and by the phenolic and volatile constituents which affect the organolectic properties. Olive oil is rich in monounsaturated fat (56-84% of oleic acid), contains 3-21% of the essential linoleic aeid [3], is low in tocopherols [4,5] and therefore the presence of phenols is important to mantain the anti-oxidative stability. Several articles [1,2,6] reviewed the reasons why olive oil should be preferable to other dietary fat, paying particular attention to the fatty acid composition. Oleic acid is antithrombotic compared to saturated fatty acids [7]. Monounsaturated and polyunsaturated fats reduced low density lipoproteins (LDL) levels. 

Sterols are crystalline alcohols present in oils, either in the free form or esterified with fatty acids. In CNO they amount to about 1000 mg/kg (ppm) and make up about 20% of the unsaponifiable fraction. Those present in the major oils do not seem to have any strong effect on their behaviour, but they do have important nutritional effects. Cholesterol, for example, which occurs overwhelmingly in animal fats, elevates serum cholesterol, and recently it has been found that phytosterols reduce it. This has led to the appearance of phytosterol-enriched margarines on the market. 

Lubricants have been used by mankind from the very early days of civilization to assist in reducing the energy needed to slide one object against another. The first lubricants were animal fats, and much later whale oil was used. It was not until crude oil was discovered in commercial quantities in Oil Springs, Ontario, Canada, in 1858 and in Titusville, Pennsylvania, in the United States in 1859 that the concept of petroleum-based lubricants could be seriously considered on a large scale. The first petroleum refinery to produce base stocks (the petroleum distillates fractions used in lubricants) in the Western Hemisphere was built by Samuel Weir in Pittsburgh in the 1850s. One of the earliest lubricant producers (to reduce waste production) was the Standard Works in Cleveland, Ohio, owned in part by John D. Rockefeller, whose company subsequently became Standard Oil. 

Silver ion chromatography is used primarily in liquid [213,215-218], thin-layer [212,213,216,219], and supercritical fluid chromatography [220-222] for the separation of fatty acid derivatives and triacylglycerols, and to a lesser extent, terpenes, sterols, carotenoids, and pheromones. Silver ion chromatography is widely used on its own, or as a preliminary simplification step, to elucidate the stmctures of fats, oils and lipids [213]. It is possible to fractionate animal or fish oils into fractions with zero to six double bonds. Species with the same total number of double bonds can be separated based on the difference in the number of double bonds in individual acyl residues. 

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