Chocolate

Question

HaRav, I am very interested to see that Chocolate is HaEtz. At what point is something considered to have "lost its original shape" (I think the Hebrew is Ibed et Tzurato?) and then become a Shehakol? Chocolate is a nut that grows on trees, which is then ground, processed with alkali, and mixed with other ingredients i.e. milk, sugar, oil and then formed into something entirely different from its original look. While we're on the topic, would Pringles potato chips be a HaAdama? They are potatoes that have been cooked, mashed, mixed with other ingredients, formed into chips and fried - much like cocao nut being turned into chocholate? That is why they stack so well! Other chips are just cut and fried. Where in Gemara and Shulchan Aruch can I read up on Ibed et Turato - or whatever it is called? Keep up the good work - I love this site, Aric