淀粉颗粒内部具有结晶区和非结晶区,淀粉的变性化学反应主要发生在非结晶区。实验表明,超声波作用的木薯淀粉颗粒基本保持着原木薯淀粉的颗粒形状,而木薯淀粉颗粒的偏光十字特征减弱或消失;超声波作用没有破坏木薯淀粉分子的原有的结构,没有新的化合物产生,经超声波作用后的木薯淀粉的红外结晶指数下降,木薯淀粉颗粒表面不再圆滑平整,说明超声作用破坏了木薯淀粉颗粒表层结晶结构。超声波作用后的木薯淀粉与原木薯淀粉分别合成羟丙基淀粉,羟丙基淀粉的取代度分别为0.1895与0.0725,说明经超声波作用后的木薯淀粉的反应性能增强,因为超声波作用后的木薯淀粉颗粒结晶结构被破坏,反应试剂更容易进入淀粉颗粒内部进行反应,反应性能得到了提高。Starch grain has crystallization area and non-crystalline area in the interior. Chemical reactions commonly occur mainly in non-crystalline area. Experiments showed that cassava starch particles of ultrasonic kept basically original cassava starch particles shape and the polarization cross of cassava starch particles weakened or disappeared. The original structure of cassava starch molecules hadn＇t been destroyed and new compounds didn＇t produced after ultrasonic. By ultrasound actions, cassava starch crystal index drop, cassava starch granular surface crystal structure had been destroyed and particle surface smooth level off no longer. Hydroxypropul starch had been synthetized respectively with cassava starch after ultrasonic and original cassava starch, degree of substitution of hydroxypropyl starch were 0.1895 and 0.0725. The experimental results showed that chemical reaction performance of cassava starch after ultrasonic had been enhanced. Starch crystalline structure had been destroyed, so chemicalreagents easily go into starch grain. Therefore the contact area increased and the performance of the starch grain in the reaction could be improved.广西科学基金(桂科基0832010);广西科学研究与技术开发计划项目(桂科能0992928-13);广西教育厅项目(201106LX127
