Principle of extruding extruded food

Extrusion processing principle of food extrusion in a nutshell: puts food material extrusion machine of high temperature and high pressure condition, and then suddenly released to atmospheric pressure, internal structures and properties of material changing process. These materials are usually made of grain raw materials, such as: rice, corn, wheat, beans, sorghum, etc., and mixed with water, fat, protein, trace elements and other ingredients. Extrusion processing method is by means of the extruder screw driver, will forward extrusion material, material mixing, stirring and friction, and the function of the high shear, the disintegration of starch grains, with timing cavity temperature, pressure, temperature can reach 150-200 ° C, pressure can reach more than 10 kg/cm2), and then to a certain shape die out instantly, and have a high temperature and high pressure suddenly drops to low temperature low pressure, including free water in the rapid gasification under pressure, the volume of water about 2000 times the expandable, puffing moment grain structure has changed, it makes raw starch starch (beta) into the cooked starch (alpha starch), At the same time into lamellar loose spongy body, grain volume expanded several times to dozens of times. During the extrusion process, all kinds of food raw materials are heated and pressurized to gelatinize starch, denaturate protein, and deactivate the activity of various enzymes that can lead to food deterioration during storage. Some naturally formed toxic substances are destroyed, and the number of microorganisms in the final product is also reduced. The extrusion process is often referred to as the HTST process because the food can reach very high temperatures during extrusion, but at these high temperatures the lag time (5-10 seconds) is very short. They tend to maximize the beneficial effects of food heating (improved digestibility) and minimize the harmful effects (Browning, destruction of various vitamins and essential amino acids, production of undesirable flavors, etc.).