Corn starch, sometimes referred to as corn flour, is a carbohydrate extracted from the endosperm of corn. This white powdery substance is used for many culinary, household, and industrial purposes. In the kitchen, corn starch is most often used as a thickening agent for sauces, gravies, glazes, soups, casseroles, pies, and other desserts.
Because corn starch is made from corn and only contains carbohydrates (no protein), it is a gluten free product.
For this reason, corn starch is an excellent gluten free alternative to flour thickeners in recipes.