My girlfriend meeting my mum

So basically I live in Italy from a few years before that I have lived in the UK, I have never had a thing for girls of my own nationality. Which seems to aggravate my mother a lot, she (lets put it lightly) dislikes the local culture and always brags about how she wants to move out as soon as possible. As I'm of age now and want to stay I'll do so, she says she is fine with that but in reality i think something different. Now I have a girlfriend , and she is like the locals. I told her once and she asked me for a picture, I showed her a few pictures and she was quite impressed, however she had to ask "where is she from", when I told her the truth her facial expression changed and she was no longer enthusiastic. She started comparing her to local hood girls and inventing multiple stereotypes. I do however want them to get along, what could she potentially do to get points with my mum. What can I do to help ease this tension?

Stop being such a Mummy's boy that she thinks she has the right to control your relationships?