I'm wondering if dehydrated potatoes, or maybe even rice and pasta would act like a leavening agent like yeast if they were ground through a mill? I know they would add flavor but like cornstarch from grapes i think, it's a thickener. Looking for some input here.
It would not leaven bread.....just thicken the dough. In order to leaven bread you need yeast either manmade from the store or natural yeast from a sourdough starter. I'm assuming you want a gluton free option, try looking up gluten free sourdough starter.