6.3 Saturated and Unsaturated Oils
Oils and fats are either saturated or unsaturated. Unsaturated oils contain double bonds between some of the carbon atoms in the chain. We can use the bromine water test to see if an oil is unsaturated (remembering that bromine water will turn colourless if the substance added is unsaturated because the bromine will react with the double bonded carbon atoms). Monosaturated fats contain one doubled bonded carbon atoms and polysaturated fats contain more than one set of double bonded carbon atoms.
Hydrogenation (HT Only)
Vegetable oils are liquid at room temperature. Vegetable oils that are unsaturated can be hardened by pumping hydrogen through them in the presence of a nickel catalyst at room temperature. The hydrogen reacts with the double bonded carbon atoms, resulting in the unsaturated hydrocarbon becoming the least partially saturated.
Hydrogenated oils have a higher melting point and are thus liquids at room temperature, making them useful as spreads and in cakes and pastries.
A vegetable oil may not be fully hydrogenated because full hydrogenated may make the substance too hard and have properties that are not desirable. For example, margarine is only partially hydrogenated because if it was fully hydrogenated it would be too hard to spread. Partially hydrogenated vegetable oils are used instead of butter in processed foods because they allow the product to keep longer and are cheaper than butter. However, partially hydrogenated vegetable oils contain transfats and there is evidence that these are bad for your health.
Vegetable oils are liquid at room temperature. Vegetable oils that are unsaturated can be hardened by pumping hydrogen through them in the presence of a nickel catalyst at room temperature. The hydrogen reacts with the double bonded carbon atoms, resulting in the unsaturated hydrocarbon becoming the least partially saturated.
Hydrogenated oils have a higher melting point and are thus liquids at room temperature, making them useful as spreads and in cakes and pastries.
A vegetable oil may not be fully hydrogenated because full hydrogenated may make the substance too hard and have properties that are not desirable. For example, margarine is only partially hydrogenated because if it was fully hydrogenated it would be too hard to spread. Partially hydrogenated vegetable oils are used instead of butter in processed foods because they allow the product to keep longer and are cheaper than butter. However, partially hydrogenated vegetable oils contain transfats and there is evidence that these are bad for your health.