Cookbook:Modified Food Starch
Modified starch is a food additive which is prepared by treating starch or starch granules, causing the starch to be partially degraded. Modified starch is used as a thickening agent, stabilizer, or an emulsifier. Starches are modified for a number of reasons. Starches may be modified to increase their stability against excessive heat, acid, shear, time and cooling or freezing; to change their texture; to decrease the viscosity, or to lengthen or shorten gelatinization time.
Acid-treated starch (E1401), usually simply called "modified starch", is prepared by treating starch or starch granules with inorganic acids, breaking down the starch molecule and thus reducing the viscosity.
Other treatments may produce modified starch with different E numbers, such as alkaline-modified starch (E1402), bleached starch (E1403), oxidized starch (E1404), enzyme-treated starch, acetylated starch (E1420), and acetylated oxidized starch (E1451).
Pre-gelatinized starch is used to thicken instant desserts, allowing the food to thicken with the addition of cold water or milk. Similarly, cheese sauce granules (such as in Macaroni and Cheese or lasagna) or gravy granules may be thickened with boiling water without the product going lumpy. Commercial pizza toppings containing modified starch will thicken when heated in the oven, keeping them on top of the pizza, and then become runny when cooled.