24.4 Bromination of Bacon Fat

Chemical Concepts Demonstrated: Saturation, saturated fats, fats and oils

Demonstration:

The flask contains bromine vapor. A fried piece of bacon is added to the flask.

Observations:

    The bromine vapors disappear from the flask.  The piece of bacon is visibly discolored.

Explanation:

    Many of the "saturated" fats found in nature aren't completely saturated.  Free fatty acids in nature are usually tied up in the forms of esters or amides.

    Fatty acid hydrocarbon chains are harder to pack into a crystal lattice when they are unsaturated.  When a lattice can be made (i.e. when a solid can be formed), the mixture of fatty acids is called a fat, while mixtures that cannot form lattices are called oils.  Therefore, fats are generally more saturated than oils.   Beef fat is about 33% unsaturated, while olive oil is 80% unsaturated.