Triacylglycerols melting point

The melting points of even-numbered-carbon fatty acids increase with chain length and decrease according to unsaturation. A triacylglycerol containing three sam-rated fatty acids of 12 carbons or more is solid at body temperature, whereas if the fatty acid residues are 18 2, it is liquid to below 0 °C. In practice, natural acylglyc-erols contain a mixture of fatty acids tailored to suit their functional roles. The membrane lipids, which must be fluid at all environmental temperatures, are... 

Fats are solid triacylglycerols, oils are liquid triacylglycerols it is the fatty acid composition of the triacylglycerol that determines its physical properties. Triacylglycerols with a high proportion of unsaturated fatty acids have lower melting points than those rich in sam-rated fatty acids, so the former are oils - that is, they are liquid at room temperature. The unsaturated fatty acids are identified by the number of carbon atoms and the position of the double bonds (see below). 

Prevention of intracellular damage lowering of the melting point of triacylglycerol reserves... 

Early work showed that interesterification of milk fat resulted in an increase in the melting point of milk fat and the concentration of high melting triacylglycerols (de Man, 1961). The effect on the melting point of milk fat was greater in the case of directed interesterification compared to random interesterification. The use of solvents in the interesterification process also enhances its effects on the melting point of the modified milk fat (Weihe, 1961). 

When interesterification of milk fat was carried out at 100°C with 0.2% sodium, there was an increase in middle-melting point triacylglycerols but only small effects on the melting properties of milk fat (Timms and Parekh, 1980). These authors concluded that although the interesterified milk fat was more compatible with cocoa butter than unmodified milk fat, the effects were not sufficient to warrant the use of interesterification (Timms and Parekh, 1980). 

Draw the products formed when triacylglycerol A is treated with each reagent, forming compounds B and C. Rank A, B, and C in order of increasing melting point. 

Fish oils, such as cod liver and herring oils, are very rich in polyunsaturated triacylglycerols. These triacylglycerols pack so poorly that they have very low melting points thus, they remain liquids even in the cold water inhabited by these fish. 

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