以大米淀粉为原料,在不同脉冲电场强度(0.0、2.5、5.0、7.5、10.0、12.5 k V/cm)及不同脉冲波数(0、180、360、540、720、900)下与乙酸锌(0.001 mol/L)反应制备大米淀粉锌络合物.对大米淀粉锌络合物中的锌含量进行测定,得出制备大米淀粉锌的最佳条件如下:电场强度7.5 k V/cm,脉冲波个数360;此时样品中锌含量由468.24 mg/kg提高到738.62 mg/kg,说明脉冲电场能促进锌与淀粉的配合反应.文中还采用扫描电镜、红外光谱、X射线光电子能谱、X射线衍射等方法对大米淀粉锌的表面光学特性及结构特性进行了研究,结果表明:乙酸锌与大米淀粉葡萄糖单元上的羟基发生了配合反应;随着电场强度和脉冲波数的增加,大米淀粉颗粒表面被破坏,相对结晶度降低,促进了配合反应,提高了配合量.
At various pulse electric field (PEF) strength (0. 0 , 2. 5 , 5. 0 , 7. 5 , 10. 0 and 12. 5kV/cm) and pulse wave number ( 0, 180, 360, 540, 720 and 900) , rice starch-Zn complex was prepared via the reaction of rice starch with zinc acetate (0. OOlmol/L) , and the Zn content in the complex was determined, finding that, under the optimal conditions for preparing rice starch-Zn complex, namely a PEF strength of 7. 5kV/cm and a pulse wave number of 360, the zinc content of the sample increases from 468. 24mg/kg to 738. 62mg/kg, which means that PEF can promote the reaction of Zn with starch. Besides, the optical characteristics and structural properties of rice starch-Zn complex were investigated by means of SEM, IR, X-ray photoelectron spectrometry and XRD. The re-sults show that zinc acetate reacts with the hydroxyl groups of glucose units on rice starch ; and that, with the in-crease of PEF strength and pulse number, the surface of rice starch particle is damaged, the relative degree of cry-stallinity is decreased, the coordination reaction is promoted and the amount of rice starch-Zn complex is increased.