LINCOLN, Neb. (AP) — A company affiliated with the University of Nebraska says a Nevada tortilla maker is infringing on a patent two university researchers received in 2002.

NUtech Ventures is suing Gruma Corp., which owns Mission Foods and Azteca Milling, over patent infringement.

NUtech, which is a nonprofit that works to commercialize the university’s research, says Gruma filed several patent applications between October 2004 and June 2007 that show it is violating NU’s patent.

At the heart of the dispute is a process to produce flour from grains such as corn that’s more efficient. The process uses a solution containing a protease enzyme.

Gruma operates 22 U.S. plants that manufacture and distribute packaged corn and wheat tortillas and six plants that manufacture and distribute corn flour.