Synthesis of potato starch sulfate and optimization of the reaction conditions.

Potato starch sulfate was obtained by the reaction between potato starch and chlorosulfonic acid in pyridine. It was characterized by FT-IR and SEM. The reaction conditions were studied systematically, which included the volume ratio of pyridine to chlorosulfonic acid, reaction temperature and time in preparing sulfating agent process, and the ratio of starch mass to chlorosulfonic acid volume, reaction temperature and time in sulfation process. Meantime, the degree of substitution (DS) of each sample was determined via barium sulfate-glutin nephelometery method. By investigating the relationship between these conditions and DS, the optimal conditions were obtained with the maximum DS.