Powdered buttermilk is to regular buttermilk as powdered milk is to regular milk - that is, it performs in all the expected ways when it is rehydrated, it just doesn’t taste the same. But since powdered buttermilk is almost exclusively used for baking, the taste difference may not be particularly noticeable.
How do I determine how much orange oil to use in place of grated orange peel? What would the ratio be?