Raw flour is a term that often appears in Hong Kong-style recipes, and it is often used for hooks. The raw flour used in Hongkong is corn flour, and the rice flour used in Taiwan Province Province is too white. 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.

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.

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

At present, potato starch is widely used in families. It is made of potatoes through grinding, cleaning and precipitation. It is characterized by sticky feet, fine texture, white color, better luster than mung bean starch, but poor water absorption.

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

Sweet potato starch is characterized by strong water absorption, but poor viscosity and dark red and black color. It is made of fresh potatoes through grinding, scrubbing and precipitation.