What it does
It gives the wet batter something to key into. A bare product surface is wet and smooth, and batter applied straight onto it adheres poorly and unevenly. The pre dust absorbs surface moisture, raises surface roughness and creates a hydrated intermediate layer that bonds to the product on one side and the batter on the other. Formulations are usually flour or starch based, sometimes with a hydrocolloid or protein to improve the bond.
Where it works
Any coated product, and particularly those with a wet, smooth or high moisture surface: marinated poultry, injected portions, seafood, and plant based products with a smooth extruded skin.
Where it does not
It cannot compensate for a product that is releasing water throughout storage. If moisture keeps migrating outward from the core, the pre dust layer will eventually saturate and the coating will separate anyway, which is why adhesion is a moisture problem before it is a glue problem.
What it interacts with
Surface moisture, which it is there to manage. The batter viscosity above it. The freezing profile, where most adhesion failures are actually created.
