In general, water starch is dry starch with water, which together is called water starch. Stir-fried things are usually dry starch, or add dry starch with egg liquid. Starch used for thickening, also known as dough powder, is a polysaccharide polymer concentrated by multiple glucose molecules. Starch used for cooking mainly includes mung bean starch, potato starch, wheat starch, water chestnut starch and lotus root starch. Starch is insoluble in water. When it is heated to 60℃ with water, it will be gelatinized into a colloidal solution. Thickening is the use of this property of starch. Starch flour: starch flour-strictly speaking, it is the general name of various starches, mainly used for thickening and dessert. It is called dough powder in the north and water chestnut powder in Shanghai, not specifically any kind of starch. In China cooking, raw flour is often used as one of the cured meat materials to soften the meat quality, besides making the food taste smooth. . Raw powder (white powder), also known as bean powder and water chestnut powder, is made from broad beans or water chestnut. Raw flour has a wide range of uses and can be used as a seasoning for cooking, bean jelly and pancake stalls. It is mainly used for sizing and thickening when processing meat raw materials. In Chinese food, it refers to starch, which is used for thickening and sizing when cooking. There are many kinds of raw flour, such as sweet potato starch, water bean powder used in Sichuan cuisine and corn starch, all of which are starch. The concept of thickening corn starch in general academic circles is that it has the characteristics of water absorption, cohesiveness and smoothness after being gelatinized by heat. When the dishes are close to maturity, pour the prepared powder juice into the pot to thicken the marinade and increase the adhesion of the marinade to the raw materials, thus increasing the powder and concentration of the soup and improving the color and taste of the dishes.