Starch acetate, also called acetylated starch, is made by treating starch with acetic anhydride or vinyl acetate, which attaches acetyl groups to the starch chains. These groups stop the chains from packing back together after cooking, so the starch forms clearer, softer pastes that stay stable instead of firming up or releasing water. It is INS 1420 and E1420, and Codex lists it as an emulsifier, stabilizer and thickener.
Stacked chips such as Lay’s Stax are not sliced from whole potatoes but formed from a potato-based dough, so starches play a large part in their texture. Starch acetate is the stabilizer named on Lay’s Stax Original, Lay’s Stax Sour Cream & Onion and the Spicy Lobster flavour.
