Pasta and rice tend to have a slow affect on BG levels, I agree with everyone here in that I'm not sure where you're getting the carbs/100g info from? I can only assume maybe it's those pre-packed microwave pasta pouch type things?
Anyway if you're eating 56g carbs from a pasta dish and inject to cover that amount of carbs, in all likeliness the insulin will start working before the carbs and you'll go low shortly after, but then go high when the insulin runs out and the pasta carbs really kick in - plus you've probably had to treat the low anyway. Split dosing should help, using trial and error - sorry fingers