Triacylglycerols saturated

Saturated fats are typically obtained from animal sources, whereas unsaturated oils are common in vegetable sources. Thus, butter and lard are high in saturated triacylglycerols, and olive oil and safflower oil are high in unsaturated triacylglycerols. An exception to this generalization is coconut oil, which is largely composed of saturated alkyl side chains. 

Unsaturated triacylglycerols have one or more double bonds in their long hydrocarbon chains, whereas saturated triacylglycerols have none. 

When cottonseed oil is required for consumption as salad oil, it must be winterized, that is, much of the more saturated triacylglycerols must be removed so that the material will remain clear when exposed to reduced temperatures, such as those likely to be encountered with refrigeration. If the more saturated glycerol esters in cottonseed oil are not removed it will solidify at temperatures encountered in a refrigerator (around 45°F or 7.2°C). 

Salad oils. Edible oils that are suitable for the production of a mayonnaise or salad dressing emulsion remain liquid at refrigerated temperatures of 40°F (4.4°C). This requirement has been defined in terms of a minimum cold test of 5 hours this measurement requires that a sample of the oil remain clear and brilliant while submerged in an ice bath. Cottonseed oil must have a portion of the more saturated triacylglycerols removed to meet the requirements of a salad oil, and this is normally achieved through winterization. 

Nutmeg contains a simple, fully saturated triacylglycerol with a molecular weight of 722. Draw its structure. 

Problem 19.56. What is the cardiovascular benefit of increasing the amount of unsaturated triacylglycerols relative to saturated triacylglycerols in the diet ... 

Chinese vegetable tallow consists primarily of tri-saturated triacylglycerols (25%) and 2-oleodi-saturated triacylglycerols (70%) of which the major... 

For the acylation, additional amounts (50% molar excess) of pyridine and acid chloride are beneficial. The reaction takes from hours to days at room temperature. The triacylglycerol product can be crystallized with good purity in some cases but in others it is necessary to use an alumina column in addition. Jensen and Pitas (1976) emphasize that, for the latter to be used efficiently, the triacylglycerol must be soluble in hexane-anhydrous diethyl ether (9 1) at room temperature. Many saturated triacylglycerols are not thus soluble and, so, have to be purified by crystallization alone. When the latter is used then ethanol is included in the crystallization solvent so that excess acid chloride is converted to the ester which remains in solution. When alumina columns are employed, care must be taken to eliminate all traces of alcohol, chloroform or water from the eluting solvents, since these can ruin the separation. Alumina columns can be run rapidly and recoveries are 80-90% (Jensen etaL, 1966). 

All of the saturated triacylglycerols of the body, and some of the unsaturated ones, can be synthesized from carbohydrates and proteins. Certain polyunsaturated fatty acids, however, are essential in the diets of higher animals. 

Fig. 3.6. Arrangement of the P - and p-form of saturated triacylglycerols in the crystalline lattice (Cartesian coordinates a, b, c)...

In special cases, a selective fluid/fluid extraction is of interest. Ethanol extracts free fatty acids (above a level of 3%) from triacylglycerols in crude oils - this is a suitable way to treat oils with exceptionally high amounts of free acids. At a given temperature, furfural can extract only the polyunsaturated triacylglycerols. On the other hand, propane under pressure preferentially solubilizes the saturated triacylglycerols and leaves behind the unsaturated ones, together with un-saponifiable matter. Pressurized propane is uti-... 

Figure 3 Growth rate of P and P crystals of saturated triacylglycerols in refined pahn oil as a function of temperature. (Reprinted from Ref. 33, courtesy of the American OU Chemists Society.)...

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