Usually when you print a string in MATLAB:
disp(\'this will print black letters\')
Can it be printed in color instead?
In MATLAB Central-File, I find this function: cprintf
I hope this solve your question.
If you fprintf() to stderr, it can come out in another colour (depending on your preferences, I think).
fprintf()
stderr
There is undocumented functionality you can (ab)use to get more than this, though.