Synthesis of starch phosphate with mechanical activated maize starch

Maize starch was mechanically activated by a customized stirring-type ball mill and used to synthesize starch phosphate by dry process with orthophosphate as esterifying agent and urea as catalyst.The effects of activation time,reaction temperature and time,the amounts of urea and phosphates,the value of pH on degree of substitution(DS) and reaction efficiency(RE) were discussed and the best reaction conditions were determined as follows: activation time 1.5 h,amount of phosphate 12%,pH 5.0,the reaction temperature 150 ℃,reaction time 2 h and amount of urea 3%.And mechanical activation maize starch's structure were characterized The results indicated that mechanical activation destroyed the crystal structure of maize starch,considerably enhanced the chemical reactivity of starch,and then promoted the DS and RE of the Maize starch phosphate.