Zombie mobs can occasionally drop vanilla Minecraft potatoes. These potatoes can be planted anywhere on the ground to let grow. Breaking the planted potatoes resets their decay time so they never go bad. Letting the crop mature just gets you more vanilla potatoes like default behavior.

Besides, there is no mean to cook potaoes. However, potatoes can provide carbonhydrates.

They also drop carrots, which can be similarly planted, and vanilla iron bars, which can be used to craft vanilla shields earlier on.

This is still an issue