If I cook whole grain pasta (or even white) and let it sit for a few hours does it become resistant starch?
Heating and cooling wheat has been shown to form resistant starch, and I haven’t seen any grain or starch where heating and cooling hasn’t formed resistant starch. But there hasn’t been a specific study of pasta:https://www.healthline.com/nutrition/cooling-resistant-starch
And you can heat the pasta back up, resistant starch remains resistant with heating. In fact, more will form the more heating and cooling cycles it goes through. But who has the time?