When two hydrogen atoms are removed from two adjacent carbon atoms, the carbon atoms use the available sites to add another bond between them, making it a double bond. A fatty acid with one double bond is said to be a monounsaturated fatty acid (mono = one).
The double bond also causes a kink in the chain. This makes it difficult to stack the chains, just as it is difficult to stack folded chairs on top of one that is partially open. The chains, like the folded chairs, fall around each other; as a result, the fat is a liquid. The greater the percentage of monounsaturated fatty acids in a fat, the more fluid it becomes.
Monounsaturated fatty acid
be formed. These fatty acids are called polyunsaturated fatty acids (poly = many). Because polyunsaturated fatty acids have two or more double bond âœkinks,â fats that contain a high per centage of polyunsaturates are liquid at room temperature. Polyunsaturates keep the membranes of cells fluid and pliable. The double bonds in polyunsaturated fatty acids are vul Polyunsaturated fatty acidnerable to attack from oxygen in the air.
The addition of oxygen (oxidation) causes changes in flavor and odor which are commonly called rancidity. Rancid oils can be toxic in large doses. To prevent oxidation in some polyunsaturated fatty acids, hydrogen is added to the double bonded carbons, break ing the additional bond and making the fatty acid more stable. This is called hydrogenation.
Hydrogenated oils are solid at room temperature. The greater the degree of saturation, the more solid a fat becomes. The lower the saturation, the more liquid it becomes. Tub margarines have a lower come in cubes.
When fatty acids are hydrogenated, they increase the sat uration of fats. A high intake of saturated fats is a risk factor for many diseases.