cornstarch

Cornstarch (also called corn flour in some regions, though distinct from cornmeal) is a refined carbohydrate produced by extracting and purifying the starch from corn kernels (Zea mays). The production process involves steeping corn in water and weak sulfurous acid, then grinding to separate the germ, fiber, and protein, leaving nearly pure starch granules that are dried and pulverized into a fine, powdery substance. The resulting product is white, odorless, and flavorless, consisting of approximately 90% amylose and amylopectin—glucose polymers that give cornstarch its characteristic thickening properties when heated with liquid.

Cornstarch is primarily composed of carbohydrates with minimal protein, fat, or fiber. It differs chemically from other starches in the shape and behavior of its granules under heat, making it particularly valued for achieving specific textures in both sweet and savory applications.

Cornstarch functions primarily as a thickening agent in sauces, gravies, soups, and puddings, where it creates a smooth, glossy finish without the cloudiness sometimes associated with flour. In Asian cuisines, particularly Chinese cooking, it is a staple for velvet (oil-blanching) marinades and for creating silky sauce coatings on stir-fried proteins. In baking and confectionery, cornstarch is blended with wheat flour to reduce gluten development and produce tender cakes and pastries, or used alone for thickening fruit pie fillings and custards. It is also employed as a dusting agent to prevent sticking and in glazes for a shiny finish. The ingredient works at lower temperatures than flour and produces clearer results, making it essential in delicate preparations like fruit compotes and dessert sauces.