Sometimes you run into a hedgehog that just won't try anything new. Its frustrating but there isn't much else you can do about it.
Keep trying and try things more than once or twice. It can take them a while to decide something isn't going to hurt them.
I've had a couple that wouldn't eat anything but kibble (including not eating mealworms). That was just who they were. Poptart will only eat mealworms, kibble & watermelon. I continue to try getting her to eat other stuff, but she likes what she likes and there is no forcing a change on her.