Preparation Of Cassava Starch Phosphate Ester Under The Dry Conditions And The Analysis Of Its Structure Properties

Starch phosphate ester is one kind of starch derivative produced from esterification of starch and phosphate. Starch phosphate ester which is being applied usually has lower combined phosphorus content, or lower degree of substitution and lower accessional value. Now it is applied in the fields of newspaper and food industry with high demands and required to have a higher combined phosphorus content. So the studies on synthesis of starch phosphate ester and its reaction mechanism would become more and more important and widen their perspective application.In this paper, reactive conditions of preparation of cassave starch phosphate ester using STP and NaH2PO4 as esterify reagent were studied. The influence factors including reaction temperature, reaction time, the value pH, the amount of esterify reagent and the amount of urea were also studied. The results show that the optimum reaction conditions using STP to prepare starch phosphate ester under the dry process are that the reaction temperature is 130~150C, reaction time 1.5~2h, pH 5, amount of STP 7%~9%, and amount of urea 4%~5%, respectively. Under the optimal conditions, the DS is 0.075 and the RE is 61.60%. The optimum reaction conditions using NaH2PO4 to prepare starch phosphate ester under the dry process are that the reaction temperature is 150~160C, reaction time 2~2.5h, pH 5.8, amount of NaH2PO4 9%, and amount of urea 6%, respectively. Under the optimal conditions, the DS is 0.093 and the RE is 68.73%.On the base of single factor experiment, even design experiment was designed under five factors and six levels, the factors including reaction temperature, reaction time, the value pH, amount of esterify reagent and the amount of urea, then analyzing the data and setting up the maths model.Rheological property of products was studied, the rheological model of different reactive conditions established. FTIR of starch phosphate ester showed that the basic structure of the modified starch wasn't destroyed, and the new groups were added to the origin starch molecule.