机构地区: 华南理工大学轻工与食品学院轻化工研究所
出 处: 《华南理工大学学报(自然科学版)》 2005年第8期91-94,共4页
摘 要: 研究了玉米淀粉经超声处理后的化学反应性能变化.将经超声处理的玉米淀粉与环氧丙烷进行反应,发现反应取代度(DS)由未处理时的0.113提高到0.225以上,同时发现提高超声功率对反应取代度有一定的促进作用,但随着作用时间的延长,反应取代度提高不明显.采用偏光显微镜研究超声处理后玉米淀粉的结构,发现超声处理后玉米淀粉整个颗粒的结晶结构变化不明显;用扫描电镜观察发现部分淀粉颗粒表面出现大小不同的小孔,部分小孔分布十分均匀,呈蜂窝状,由此推断超声对淀粉的作用只发生在淀粉颗粒表面的无定形区. The change of the chemical reaction property of ultrasound-treated cornstarch (UTCS) was investigated By the reaction of UTCS with epoxy-propane, it is found that the degree of substitution (Ds ) of UTCS increases from 0. 113 (the control sample) to more than 0. 225, and that the Ds of UTCS increases a little with ultrasonic power. However, the increase in reaction time results in little improvement of the Ds. It is also found by polarized light micrograph that the crystal structure of UTCS granules shows no great change after the treatment by ultrasonic. Moreover, by using the scan electronic microcopy (SEM), many holes with different sizes are observed on the surface of UTCS granule, some of which take on the alveolate shape and distribute evenly in some starch articles. It is thus concluded that the ultrasonic contributes only in the amorphous region on the surface of the starch granule.