In short:

Starch: usually extracted from corn or sweet potato;

Four is processed wheat;

Cornstarch: Strictly speaking, it is the general name for various starches. It is mainly used for thickening and snacks. In the north, it is called dough flour, but it is actually no different from starch.

Specific differences:

Starch:

It is the polymerization of glucose molecules. It is the most common storage form of carbohydrates in cells. [1] Starch is also called starch in the catering industry. The general formula is (C6H10O5)n. When hydrolyzed to the disaccharide stage, it becomes maltose. The chemical formula is C12H22O11. After complete hydrolysis, it obtains monosaccharide (glucose). The chemical formula is C6H12O6. There are two types of starch: amylose and amylopectin. The former is an unbranched helical structure; the latter is composed of 24 to 30 glucose residues connected head to tail by α-1,4-glycosidic bonds, with α-1,6-glycosidic bonds at the branches. Amylose turns blue when exposed to iodine, and amylopectin turns purple when exposed to iodine. This is not due to a chemical reaction or interaction between starch and iodine, but because the hole in the center of the starch helix can accommodate iodine molecules, and through van der Waals forces, the two form a blue-black complex. Experiments have shown that iodine molecules alone cannot turn starch blue. In fact, it is the iodine molecular ion (I3) that turns starch blue. Starch is a nutrient stored in plants. It is stored in seeds and tubers. The starch content in all types of plants is high. Starch can be thought of as a high polymer of glucose. In addition to being edible, starch is also used industrially to make dextrin, maltose, glucose, alcohol, etc. It is also used to prepare printing paste, sizing textiles, gluing paper, and pressing pharmaceutical tablets. It can be extracted from starchy substances such as corn, sweet potato, wild acorns and kudzu root.

Flour:

A powder ground from wheat. According to the protein content in flour, it can be divided into high-gluten flour, medium-gluten flour, low-gluten flour and gluten-free flour. Flour (wheat flour) is a staple food in much of northern China. There are many kinds of foods made from flour, with various styles and different flavors