Potato Starch (Best Option)
1:1 by volume (1 tablespoon potato starch per 1 tablespoon arrowroot powder)Potato starch is a fine, neutral-tasting starch that gelatinizes at a similar temperature to arrowroot, providing excellent binding and moisture retention in meatloaf. It forms a smooth, glossy texture that helps the meatloaf hold together without heaviness.
When using potato starch, mix it thoroughly with the wet ingredients before combining with meat to avoid clumping. Avoid overcooking as excessive heat can break down the starch, reducing its binding power.
Compared to arrowroot, potato starch yields a slightly denser but still tender meatloaf with excellent moisture retention and no off-flavors, making it the closest functional match.