Why is coconut oil solid at room temperature, when most oils are not? I stop to think about this every time I cook something with coconut milk, but have never bothered to look up the answer until now (I made a laksa today).
Turns out it has to do with the ridiculously high (92%) saturated fat content of coconut oil. Being solid at room temperature is one of the characteristics of saturated fat, hence the properties of not only coconut oil, but also butter, ghee, lard and palm kernel oil amongst others.
All fats are comprised of a blend of organic compounds known as fatty acids; in saturated fats, these fatty acids are all ‘saturated’ in a chemical sense, meaning there is a maximal possible number of hydrogen atoms in the chain forming the acid. This chemical constitution gives it the property of being solid at room temperature, although depending on the particular blend of fats in any substance, it can have various degrees of solidity.
Liquid oils, on the other hand, contain a high amount of oleic acid, which is ‘unsaturated’, meaning that in contains not only carbon-hydrogen bonds, but also double bonds, where carbon binds with carbon. Whenever a double bond takes place, there is less room in the molecule for hydrogen atoms, hence the lesser degree of saturation.
With more and more health researching surrounding macronutrients, saturated fats have been increasingly associated with things like heart disease. Hence dietary guidelines worldwide advise to limit saturated fat intake, and concentrate on using vegetable oils and other fats that contain less hydrogen.
Learning about the meaning of ‘saturation’ in chemistry made me realise that it’s one of those technical terms that has made its way into everyday life. Everyone has heard about the different fats.
I wonder what other scientific terms we use without knowing their specific use in chemistry, physics or elsewhere. Do you have examples?