The unsaponifiable portion of an oil is the portion of the oil that contains phytosterols, hydrocarbons like squalane, tocopherols, carotenoids, fatty alcohols, and triterpenoids, like steroids or cholesterol. They’re called unsaponifiables or unsaponifiable because they will not be turned to soap when the oils are added to the lye during the process of saponification. These unsaponifiables comprise up to 2% or 3% of an oil.
Check out this post – What is an unsaponifiable? by The Original ASU – for more information.