What causes creases in fatty acids

Name: Lorena Zveki─ç, 2015
Hopemaster, 2021-03

Fats consist of glycerine, which are esterified with three (mostly different) fatty acids (= long-chain carboxylic acids). That is why fats are called triglycerides. Fats are divided into two different groups: saturated and unsaturated fats. They are lipids because the (long) non-polar carbon chain outweighs the small polar center. This means that they are soluble in non-polar / lipophilic solvents such as benzene or ether. In nature, fats serve primarily as energy stores and reserves, and are also heat insulation and cushioning materials for organs and muscles.

Saturated fats

Saturated fats are mainly of animal origin. Because they do not have a double bond, they are usually solids at room temperature and are therefore called fats. Due to the parallel arrangement of the fatty acids, they have higher van der Waals forces and thus a higher boiling and melting temperature.

Unsaturated fats

Unsaturated fats are mainly of vegetable origin. Because they have double bonds, they are usually liquids at room temperature and are therefore called fatty oils. Fatty oils are not as easily converted into body fat and are therefore more essential for nutrition than fats. The fatty acids with double bonds contained in fats create a kind of `` kink ''.

This `` kink '' prevents the fatty acids from being laid on top of each other so that there is a greater distance between them than with saturated fats.

This has an enormous impact on the development of Van der Waals forces. Often these interactions no longer develop at all. So much less energy is required (room temperature is sufficient) to change the physical state from solid to liquid, as fewer interactions have to be overcome. As a result, the boiling and melting point of unsaturated fats is lower than that of saturated fats.

But be careful, some vegetable oils flocculate in the refrigerator because they reach their melting point (e.g. olive oil)

The unsaturated fatty acids are divided into cis fatty acids and trans fatty acids. The natural fatty acids are cis-fatty acids and are therefore more common. Because it is not possible to arrange cis-glyrides in parallel, they have weaker van der Waals forces and thus a lower boiling and melting temperature.