Italian to German Tech/Engineering Petroleum Eng/Sci Bitumen

From a chemical-physical point of view, bitumens are complex mixtures of various hydrocarbons, normally classified into some main families according to their nature and rheological behaviour:

***maltenici oils***, subdivided into compounds of an aromatic nature or saturates, responsible for the ability of bitumen to flow and wet the surfaces to be covered.

What are "maltenici oils" and how would you translate the term into German?

Many thanks!