FACTORS INFLUENCING THE DEGREE OF SUBSTITUTION OF PHOSPATE MONOESTER OF SWEET POTATO STARCH

摘要

In present paper, the factors influencing the degree of substitution (DS) of phosphate monoester of Sweet Potato starch esterified by disodium hydrogen phosphate (Na_2HPO_4) and sodium dihydrogen phosphate (NaH_2PO_4) were investigated. The results indicated that DS of phosphate monoester increased with the level of esterifying agent, reaction temperature and time, and the amount of catalyzer. However, when pH increased, DS first increased and then decreased. The combination of Na_2HP0_4 and NaH_2P0_4 and vacuum had no marked influence on DS. Based on above results, the optimum parameters for the preparation of phosphate monoester of Sweet Potato starch was selected as follows: the reaction temperature was 130~140 °C, reaction time was 2-3 h, pH value was 5.5-6.0, and the concentration of catalyzer was 4-6% of starch dry weight.