Raw flour is a term that often appears in Hong Kong-style recipes, and it is mostly used for gouzi. In Hong Kong, raw flour is corn flour, while in Taiwan Province, the common glutinous rice flour is too white. In Chinese cooking, raw flour is often used as one of the cured meat materials to soften the meat quality, in addition to making food taste smooth. Raw flour (that is, white powder), also known as bean powder and water chestnut powder, is made of broad beans or water chestnut. Raw flour has a wide range of uses, which can be used as seasoning for cooking, bean jelly and pancake spreading. Mainly used for sizing, thickening and so on 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, which are starch. Generally, the academic concept of corn starch thickening is that it has the characteristics of water absorption, adhesion and smoothness when gelatinized by heat. When the dishes are close to maturity, pour the prepared powder juice into the pot to make the marinade thick 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.

starch used for thickening, also called dough powder, is a polysaccharide polymer condensed from 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, and when it is heated to 6C with water, it will be gelatinized into a colloidal solution. Thickening is to use this property of starch.

Mung bean starch is the best starch, which is seldom used. It is made of mung beans by grinding and precipitating with water. It is characterized by sufficient viscosity, small water absorption and white and shiny color.

Potato starch is commonly used in families at present. It is made from potato by grinding, washing and settling. It is characterized by sticky foot, fine texture, white color, better luster than mung bean starch, but poor water absorption.

Wheat starch is precipitated from wheat bran after gluten washing or made from flour, which is characterized by white color, poor luster and inferior quality to potato flour, and is easy to precipitate after thickening.

Sweet potato starch is characterized by strong water absorption, but poor viscosity, dull color and dark red with black. It is made from fresh potatoes by grinding, kneading and washing, and precipitating.