Graduate School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
Carbohydr Polym. 2013 Apr 2;93(2):582-8. doi: 10.1016/j.carbpol.2012.12.050. Epub 2012 Dec 26.
Waxy maize starch was dispersed (14.7% solids) in an aqueous sulfuric acid solution (3.16M), and hydrolyzed by stirring for up to 7 days at 40°C with ultrasonic treatments at different vibration amplitudes (20 and 40%) and durations (30 and 60min/day). The amount of starch nanoparticles in the hydrolyzates isolated after 7 days, measured by a dynamic light scattering detector, was raised from 20% to 70% by an ultrasonic treatment (20% amplitude, 30min). The aggregation of nanoparticles possibly occurring during the hydrolysis was effectively prevented by the ultrasonication. Alternatively, ultrasonic treatments were applied to the re-dispersed suspension of the large microparticles of starch hydrolyzates (2 days) precipitated by a mild centrifugation (500rpm, 10min). By an ultrasonic treatment at 60% vibration amplitude for 3min, the microparticles could be completely transformed to nanoparticles. The inherent crystalline structure of waxy maize starch (A-type in X-ray diffraction) remained after the ultrasonic treatments during acid hydrolysis, but it was disrupted by the ultrasonic treatments for the re-dispersed microparticles.
糯玉米淀粉在硫酸水溶液（3.16M）中分散（固含量 14.7%），在 40°C 下搅拌 7 天，并通过不同振动幅度（20%和 40%）和时间（30 分钟和 60 分钟/天）的超声处理进行水解。通过动态光散射探测器测量，在 7 天后分离的水解物中淀粉纳米颗粒的数量从 20%增加到 70%，通过超声处理（20%幅度，30 分钟）。超声处理有效地防止了水解过程中纳米颗粒的聚集。或者，将超声处理应用于通过温和离心（500rpm，10min）沉淀的淀粉水解物的大微颗粒的再分散悬浮液（2 天）。通过 60%振动幅度的超声处理 3 分钟，可以将微颗粒完全转化为纳米颗粒。在酸水解过程中的超声处理下，糯玉米淀粉的固有结晶结构（X 射线衍射中的 A 型）得以保留，但对再分散的微颗粒进行超声处理会破坏其结晶结构。
