The 'title' for your apprentice is just a matter of number of recipes it's researched. It's just a title, it doesn't change or 'do' anything.
I wish they would do something with the apprentices, both of mine have researched all of their recipes so now they just occupy space. Its a shame to keep putting in systems and then just let them languish on the vine while they put in even more systems to follow the same pattern. Cyrrena