Working principle and practical application of twin-screw extruder

Working Principle of Twin Screw Extrusion

After a certain amount of pulverization, the material with a certain water content is fed into the extruder cavity, so that the material will undergo mixing, shearing, A series of complex continuous processes such as melting, curing and sterilization. Because there is a certain air pressure difference inside and outside the barrel, the moment the material is extruded, the external pressure it is subjected to is reduced to normal pressure, so that the material is instantly puffed. After extrusion and puffing, the degree of gelatinization is improved, it is easier to be hydrolyzed by enzymes, the rehydration is good, and the processing performance is also greatly improved. In addition, when the material is subjected to high temperature and high shear force in the barrel, some macromolecular substances such as protein and starch will undergo deformation and structural reorganization, gelatinization and cracking; some small molecular substances such as amino acids and reducing sugars will occur Maillard reaction.

Application classification of twin screw extruder

The food produced by the twin-screw extruder is mainly divided into two categories: the first type uses grains and potatoes such as rice, corn and sweet potatoes as raw materials, which are extruded, baked, dehydrated, fried, and then seasoned with various flavors. Puffed rice cake, puffed twist, puffed buckwheat slices, etc. all belong to this category of products;

The other type is the puffed sandwich snack food. When extruding and puffing, the sandwich material is passed through the corresponding machine and the corresponding mold, and the cheese, chocolate, sugar, etc. are stuffed while the extruded product is extruded in the puffing machine. The material is injected into the hollow space of the product to form puffed sandwich snacks, thereby making puffed sandwich snacks. On the one hand, this kind of food has the characteristics of fluffy and crispy due to the puffing effect, and on the other hand, the types of fillings injected can be adjusted to make it have different flavors.