Method for preparing v-type pregelatinized hydroxypropyl starch with high degree of substitution

Abstract

A method for preparing V-type pregelatinized hydroxypropyl starch including the following steps: extruding a mixture of starch and an ethanol aqueous solution—with the ethanol concentration of the solution ranging from 30% to 50% by volume and the mass ratio of starch to the ethanol aqueous solution being 1:0.4 to 1:1—to form an extrudate, followed by drying and pulverizing the extrudate to obtain extrusion-modified starch A; then contacting extrusion-modified starch A with an ethanol solution, adjusting the pH of the mixture to an alkaline range, reacting the mixture with propylene oxide under specified reaction conditions to form a reaction system, adjusting the pH of the reaction system to an acidic range to terminate the reaction, separating the solid product from the system via suction filtration, washing the solid product, and drying it to obtain the target V-type pregelatinized hydroxypropyl starch.

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