Do I need to modify my product formula if I am replacing maltodextrin with Milk Protein Permeate (MPP)?

That would depend on the application, but in general, you will probably have to modify your product formula. Maltodextrin does not have a significant mineral content while MPP contains approximately 8% mineral content. A significant portion of the MPP mineral content comes from potassium, calcium, and magnesium. These minerals can interfere with gum stabilizing systems and emulsification systems. Therefore, care must be taken to prevent the minerals from interfering with product stability by sequestering the mineral activity. Addition of sequestrant salts, such as disodium or dipotassium phosphate should help decrease mineral reactivity with the rest of the product ingredients. If the product contains iota or lambda carrageenan and/or guar gum, you might find that you can decrease gum usage levels when substituting MPP for maltodextrin, or any other ingredient with little or no mineral composition, because calcium acts synergistically with these gums to enhance gelling and water binding.