What food group does baking powder come in?

Baking Powder would be more of an additive than a food group. If a base component if Baking Powder is Corn Flour, and then Cream of Tartar - one could say it is more in the grain group. (Cream of Tartar would be a byproduct of wide fermintation, but the tartar itself is nothing more than an additive at that point, so it can't live in the fruits group... So- Baking Powder, as an additive, could be considered a cousin of the grains group.