机械活化木薯淀粉氧化产物的结构表征

Structural characterization of oxidation products prepared from mechanical activated cassava starch

采用搅拌球磨机对木薯淀粉进行机械活化,以活化60min的木薯淀粉为原料,CuSO4为催化剂,H2O2为氧化剂干法制备氧化淀粉。利用红外光谱、扫描电子显微镜、X-射线衍射等手段对产物的结构进行表征分析,并与原淀粉的氧化产物进行比较。结果表明,机械活化对木薯淀粉的氧化反应有显著的影响。原木薯淀粉的氧化反应主要发生在淀粉颗粒的表面及无定形区,部分发生在结晶区,产物是无定形及结晶状态的结构;活化淀粉的氧化反应在淀粉团粒表面及内部均匀进行,产物是无定形的聚集状态结构。并就机械活化对淀粉氧化的强化机理进行了探讨。

The oxidized starch was prepared by dry method using the cassava starch, mechanically activated for 60 min by a stirringtype ball mill, as a starting material, CuSO4 as catalyst and H2O2 as oxidant. Then the structures of the products were characterized by fourier transform infrared spectrescopy（FTIR） ,scanning electro microscopy（SEM） and X-ray diffraction（XRD） ,and the results were compared with the oxidized starch prepared from native cassava starch. The results indicated that mechanical activation considerably influenced on the oxidation reaction of the cassava starch. The oxidation reacion of native starch occurred in both of the surface of the starch granules and amorphous regions mostly and some occurred in crystalline regions, and its structure consisted of crystalline and amorphous. The oxidation reacion of activated starch occurred in both of the surface of the starch granules and interior comparably, and its structure was amorphous. Furthermore, the enhancement mechanism of the mechanical activation on the oxidation reaction of cassava starch was investigated.