Abstract: The objective of the present study was the optimization of the preparation process for hydroxypropyl porous corn starch in a microwave reactor. The operation conditions starch milk concentration, microwave treatment time, microwave power and propylene oxide amount were optimized by single factor and orthogonal array design methods based on degree of molar substitution, and their optimum levels were found to be 30%, 3 min and 300 W and 6.90%, respectively. Under the optimized conditions, the degree of molar substitution was 0.0103.

Key words: porous corn starch, hydroxypropyl starch, microwave radiation, degree of molar substitution