摘要：In food extrusion, a number of ingredients is used as feed materials. One of these materials is raw or processed starch. During extrusion, starch undergoes physical and physicochemical changes, including gelatinization and fragmentation. Extruded products have been characterized by various quality criteria. These quality criteria are expansion, bulk density, water absorption index and water solubility index. The most important factors that are affects these criteria are process variables such as barrel temperature, screw geometry and screw speed, and source of starch. While both individual and combination of increased barrel temperature and screw speed increase expansion, water absorption and water solubility, decrease bulk density.
