In cooking, selecting a correct type of lipid is very important because each lipid performs best within a certain range of temperature. The melting point of lipids can be defined as the temperature at which a solid fat becomes a liquid. Different types of lipids have different melting point temperatures due to the differences in their chemical structures (Table 6.3). As a general rule:• The lipids with longer hydrocarbon chains have higher melting points. In other words, the melting point increases as the molecular weight of lipids increases. • The unsaturated lipids tend to have lower melting points than saturated lipids of the same length. In other words, the melting point of lipids decreases as the degree of unsaturation in fatty acids increases. For example, butter has a higher melting point compared to olive oil (Table 6.3). The structure of saturated fatty acids is relatively linear compared to the structure of unsaturated fatty acids. This structure allows fatty acid molecules to get closely stacked together. Therefore, close intermolecular interactions result in relatively high melting points. On the other hand, double bonds in unsaturated fatty acids result in bends in their molecular structures. Therefore, these molecules do not stack very well. The intermolecular interactions are much TABLE.
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