What Is Oleic Acid?
Oleic acid is a fatty acid classified as a monounsaturated fatty acid. In other words, it is a type of unsaturated fatty acid that has unsaturated bonds in its molecule. It is found in vegetable oils such as olive oil, safflower oil, rapeseed oil, or sunflower oil.
Oleic acid in vegetable oils exist in the form of triglycerides (triacylglycerols), which are ester bonds with glycerol.
Oleic acid have unsaturated bonds in its molecule, making it more susceptible to oxidation than saturated fatty acids such as stearic acid.
Structure of Oleic Acid
The molecular structure of oleic acid are similar to that of stearic acid, the main component of animal fats, or linoleic acid and linolenic acid, which are found in vegetable fats. The molecular structural formula for oleic acid are CH3(CH2)7CH=CH(CH2)7COOH.
Both fatty acids have 18 carbons and are highly hydrophobic and insoluble in water. Each fatty acid also has one carboxy group (-COOH) in its molecule; the 17-carbon linkage corresponds to a fat, and the carboxy group corresponds to an acid.
Oleic acid differs from stearic acid and linoleic acid in the number and position of its unsaturated bonds. in its molecule. Linoleic acid has two unsaturated bonds and linolenic acid has three unsaturated bonds.
Properties of Oleic Acid
The properties of oleic acid are due to its molecular structure. Oleic acid are liquid while stearic acid, which has the same number of carbons but no unsaturated bonds, is solid at room temperature. Oleic acid has melting point around 13°C, so it does not solidify like lard unless the temperature is low, such as during winter, and then it remains in a liquid state.
Oleic acid also has carboxy groups in its molecule, which can be neutralized with an alkali to disperse it in water and produce a surfactant effect similar to that of soap.
Uses of Oleic Acid
Triglycerides of oleic acid are used as edible fats and oils, while oleic acid obtained from triglycerides is mainly used as an industrial raw material. Oleic acid is used as a raw material for surfactants, as a compounding ingredient for printing inks, as an antifoaming agent, as an additive for lubricating oils, and as an oily ingredient for cosmetics and pharmaceuticals.
For example, oleic acid can be used as a pre-reactive raw material to synthesize surfactants by reacting it with other raw materials. Furthermore, by neutralizing oleic acid with an alkaline agent, it can be given a soap-like function.
Other Information on Oleic Acid
Although not oleic acid itself, vegetable oils containing triglycerides of oleic acid can have beneficial effects on the body. Specifically, it is said to suppress LDL cholesterol, which is considered the bad cholesterol.
Vegetable oils containing unsaturated fatty acids such as oleic acid are liquid at room temperature, as described above. Liquid vegetable oils are converted to solid fats such as margarine through a chemical reaction that converts unsaturated bonds to saturated bonds. A chemical reaction called hydrogenation is used to artificially create butter-like solid fats and oils from vegetable oils.
Hydrogenation changes some oleic acid from cis-type to trans-type with unsaturated bonds to form eridic acid. Elaidic acid is similar to oleic acid, but is a trans fatty acid. Trans fatty acids have been introduced when the subject of research as substances that may have harmful effects into the body in large amounts as food.