Abstract: In this paper, carboxymethyl corn porous starch was prepared by adding chlorine acetic acid and ethanol. The effects of the degree of substitution to temperature, time, sodium hydroxide amount, chlorine acetic acid amount and ethanol concentra- tion were also discussed. With the degree of substitution, the optimal conditions for carboxymethyl porous starch were obtained through single factor and orthogonal experiments: reaction temperature 45℃, reaction time 6h, sodium hydroxide amount 4.0g, chlorine acetic acid amount was 4.5g and ethanol concentration 95%. When compared with raw corn starch and porous starch in the physicochemical and paste rheological properties, there were more finer improvements in carboxymethyl porous starch.

Key words: porous starch, carboxymethyl, complex modified starch, physicochemical property, paste rheological property