There are many brands, varieties and tastes of puffed food. Many people like it, especially children. Puffed food machinery can process rice, corn, soybean, wheat and so on in daily life. Its main working principle is that the mechanical energy can be transformed into heat energy. When the machine rotates, the heat generated will be used to extrude and cook the food, and then it will be puffed. The most obvious characteristic of food is the volume enlargement. The various functions of puffed food machinery make it widely used in the fields of food, feed and industry. Based on the puffer, we introduce the functions of puffer in the process of food or feed processing. Let's take a look at the twin-screw puffer together.
Coagulation: In the process of puffing, food or feed materials can be closely combined and condensed into discrete pieces.
Degassing: Food or feed materials containing bubbles will be degassed during puffing.
Dehydration: In the expansion process of general food or feed, the water content will lose 4%-7% on the original basis.
Expansion: The operating conditions and configuration of the extruder can control the sparse density (such as sinking or floating) of pet feed and aquatic feed.
Gelatinization: Extruded cooking can gelatinize starch (from various sources, such as tubers or grains) during the processing of food or pet feed.
Grinding: In the process of food or feed processing, raw materials can be ground to a certain extent in the extruder.
Homogenization: Homogenization of an expander changes the structure of an unattractive material to a more acceptable form.
Mixing action: In the process of extrusion treatment, various extruders have a variety of screw options, which can make the extruder produce the desired mixing amount.
Pasteur sterilization and sterilization: Pasteur sterilization or sterilization of raw materials by means of puffing technology in the puffing process of food or feed
Working Principle of Twin Screw Extruder
1. Structure of twin-screw extruder
Material is sent to the conditioner by conveying equipment. Material is conditioned by high temperature steam in the conditioner. The material enters the expanding mechanism through the discharge trough. Under a pair of parallel meshing screw pumps, the material is instantaneously extruded and cut into granules from a certain shape of die hole.
2. Expanding Principle of Twin Screw Extruder
Typical expansion mechanism of twin-screw extruder is driven forward by a pair of parallel meshing screw. The screw is divided into three sections: feeding section, compression melting section and uniform section. In feeding section, the material enters the barrel from the hopper. With the rotation of the screw, it moves forward along the screw groove direction and is gradually compacted. After shrinkage melting stage, the pressure rises due to the change of screw structure, the external heating from the barrel and the intense stirring, mixing and shearing of the material between the two screw and barrel, the material temperature rises and begins to melt until all melts. As the space of the screw tank becomes smaller, the material temperature rises further. Pressure, cooking, full gelatinization of raw starch, denaturation of fat and protein, a series of complex biochemical reactions, further homogenization of tissues, to reach the uniform section, through the shunt plate will evenly distribute the material from the "expansion chamber" to the template, at this time the pressure is usually 3-6 Mpa (depending on the expansion requirements), the temperature can reach 150-200 C, because in the closed. This high pressure in the sleeve exceeds the saturated vapor pressure at the extrusion temperature, so the water will not evaporate rapidly. When the material is extruded instantaneously from a certain shape of die hole, the pressure releases rapidly, the free water evaporates sharply, the material expands accordingly, and the water is quickly dispersed from the material, so that the product is quickly cooled to about 80 degrees Celsius and solidified. Shape and maintain its expanded shape.
