Asphaltenes are important because they have a certain structure and collect at water-oil interfaces because of it. (see the image to the left) This type of structure is called amphiphilic.Bitumen is a very complex hydrocarbon. It is formed of many different parts. These parts have been divided into two different "classes", maltenes and asphaltenes, which are defined according to what they can be dissolved in. Asphaltenes dissolve in heptane and maltenes do not. Deasphalted bitumen is the same thing as maltenes. Simply the bitumen without asphaltenes.
Asphaltenes are important because they have a certain structure and collect at water-oil interfaces because of it. (see the image to the left) This type of structure is called amphiphilic.