超高压辅助制备醋酸酯淀粉结构性质研究

以玉米淀粉为原料,乙酸酐为反应试剂,NaCl为反应介质,采用超高压辅助制备醋酸酯淀粉,利用光学显微、X-射线衍射、快速黏度分析技术对醋酸酯淀粉结构性质进行分析。研究表明,颗粒态醋酸酯淀粉结晶类型与原淀粉相同,当处理压力为600 MPa时淀粉糊化,颗粒结构被破坏,A型结晶向V型结晶转换,但糊化并不利于醋酸酯淀粉取代度的增加。适量NaCl的添加有利于超高压处理时淀粉颗粒态的维持,因而有效提高了醋酸酯淀粉的取代度。当NaCl溶液浓度为1.0%、乙酸酐添加量为2.0%、压力为400MPa时,所制备的醋酸酯淀粉取代度达到最大值(0.090),且表现出较高的峰值黏度(400.00cP)。

Structure and properties of acetylated corn starch prepared under ultra high pressure (UHP)

The acetylated starches from corn were prepared under ultra high pressure (UHP) by acetic anhydride as reaction reagent, and NaCl as the reaction medium. The structure and properties of acetylated starches were analyzed by using light microscope, X-ray diffractometer and rapid viscosity analyzer. The results indicated that the granular acetylated starch showed a similar crystallite structure as that of native starch. In addition, the acetylated starches were gelatinized when treated at 600 MPa and the structure of starch granules was gradually destroyed, whereas the crystal structure was transformed from the A-type crystallite to the V-type crystallite. However the gelatinization negatively affected the degree of substitution of acetylated starch. The appropriate amount of NaCl favored the maintenance of starch granular structure under UHP, which would effectively increase the degree of substitution of acetylated starch. The degree of substitution and peak viscosity of acetylated starch reached the highest value (0.090 and 400.00 cP, respectively) when corn starch was treated at 400 MPa with the concentration of the solution at 1.0% and the amount of acetic anhydride at 2.0%.