from what I understand canola oil is very fragile and should not be used in high heats. I have cut it out of my diet totally.

For deep frying peanut oil would be a better option if you dont want to use lard.

Coconut and sesame oils are also good for frying as well as butter and olive oil but I dont think you want to deep fry in those.

Also make sure not to reuse the oil.