How to inactivate trypsin permanently by boiling?
In my experience 10min at 100°C are sufficient, this is also supported by the paper linked below. Heat inactivation works by denaturing the protein and is therefore final. 
Depending on what you want to do with you sample, it might be problematic, as this is probably also denaturated at least to some degree.

You can also chemically inactivate trypsin, either by adding fetal bovine serum (which is done in cell culture), which contains protease inhibitors as α1-antitrypsin and α2-macroglobulin or by using commercially available inhibitors. Trypsin is also inhibited by calcium and magnesium ions, so your reaction buffers shouldn't contain any of them.


A Simple Procedure for Effective Quenching of Trypsin Activity and
Prevention of 18O-Labeling Back-Exchange