Discussion of screw pregelatinized starch extrusion method
Screw pregelatinized starch extrusion method.
Ingredients: potato starch.
Production process: starch→starch milk→gelatinization→drying→crushing and packing operation points: The starch production has the following three kinds of methods: roller method:hydroxyethyl cellulose
dual roller and single drum. The movement direction of two rollers of double drum dryer is opposite. After be inputted into the two roller when it reaches 150 ℃, problems
starch emulsion is immediately gelatinized. There is a thin film on its surface after drying, and scraping it and you will get the products. Its quality depends on the degree of gelatinization. Through the regulation of starch milk concentration, roller temperature and speed to adjust the product under shear capacity, the drying process of aging and viscosity properties. Single roller method is directly delivered to the cylinder surface of starch milk at 150 ℃ for pasting. Single cylinder has low thermal efficiency and small capacity. Spray method: in the continuous jet cooker, with high pressure steam milk mixed with starch to paste, and then spray drying.
High viscosity paste solution is not suitable for spray drying method, and the preparation cost is higher. It is general rarely used. Extrusion method: Using screw extrusion machine, it is a method for producing the pregelatinized starch by extrusion principle.cellulose derivative adhesives
Put the wet starch preset ted with water content 15 - 20% into extrusion machine, which is gelatinized by the heat generated by the starch of spiral shaft friction, and then extruded with high pressure through the aperture with small 1 - 10 mm. Entered into the atmosphere, material instantaneous expansion and drying. After crushing and screening, we get the pregelatinized starch. Due to the shear stress of high strength, product viscosity decreased, and of big solubility than produced by large drum. Because in the manufacturing process, it basically does not need to add water, and can maintain the temperature of 120--160 DEG C using the internal friction. It is drying and need not heat, so it is the most recognized economical method.