The processing of food essentially refers to a series of physical and chemical changes that occur during the processing of various raw material molecules. Extrusion cooking is an operation in which materials are discharged into a screw extruder and become products or semi-finished products through the extrusion die under different operating conditions (conveying, heating, mixing, shearing, cooking, and forming). The basic process is that food raw materials are mixed according to different formulas, and after pretreatment, they enter the screw extruder. Under the comprehensive action of the screw, they are transformed into dough with non-Newtonian fluid characteristics, and are continuously sheared and heated. Under the greater pressure at the die, the starch in the food raw materials is gelatinized and the protein is denatured. The entire extrusion process is completed within 30 to 300 seconds. The required heating temperature depends on different products, generally in the range of 50~180 ℃. When food raw materials are extruded out of the die, due to the sudden drop in pressure, the water vapor evaporates rapidly, causing the product to expand and form a porous structure. This extrusion cooking method is very different from the traditional food processing methods. The special heating and pressurizing method during the extrusion process can have beneficial effects on food quality, such as maximizing digestibility, fast-eat-bility, sterilization, while often minimizing harmful effects (such as nutritional destruction) on food.