Hey - good luck with this. If you used something by us (Kayo Dot), it would be really flattering! You might have a good chance with it too, because I've taken classes surrounded by the attitudes you mentioned... actually, our album is really conscient of the Academic myth of separation of "folk" and "serious" music, and a lot of the things we did on our album were to help dismantle this terrible myth.
I would suggest, as someone who has been in your shoes, that if you use something of ours, you should also remind your professor that the album was released on the Composer's Series on Tzadik, which is a very prestigious label for contemporary classical composition. In addition, you can check out and maybe cite the essay by Scott Johnson in Arcana: Musicians on Music (it's chapter two) in which he discusses the evolution of modern serious music - how the assimilation of our current "folk" musics (a.k.a. rock genres) into "serious" music is directly analogous to the way European classical composers like Mozart or whomever assimilated the folk musics of their own time into their own "serious" music.
Just try to win the guy over intelligently with facts and examples, without hostility, and maybe he'll see your point of view. If not, then is the time to get angry.