Why is it bad to roast with cold-pressed oils??

[Rainydaze]

Ooops, I've just roasted potatoes in cold-pressed sunflower oil...this was a mistake, wasn't it???

Why?

Nah not a mistake I don't imagine - I think the theory is that it's just a bit of a waste is all. I think you're meant to save the cold pressed stuff for raw eating as it were in dressings & mayo and such like.

No mistake. I regularly finish part boiled new potatoes in the oven with a drizzle of extra virgin olive oil and rosemary.

Ah, thank you. They were really tasty and crispy!

Mmmmmmm, yes I should have added some rosemary Trublatmill.

I thought that if you use cold pressed oils in high temps.(frying or baking) it changes their chemical make up from polyunsaturated to saturated fat.