Influence of ultrasonic treatment on formation of amylose nanoparticles prepared by nanoprecipitation

Amylose aqueous solutions (1 wt%, 3 wt% and 5 wt%) were treated with 100W ultrasound for various periods of time and used to prepare amylose nanoparticles (ANPs) via nanoprecipitation by adding the amylose solutions drop-wise into absolute ethanol. Viscosity average molecular weight and size distribution of the ultrasonic treated amylose were determined by measuring intrinsic viscosity and using size exclusion chromatography, respectively. The ANPs were characterized using dynamic light scattering, scanning electron microscopy, and X-ray diffraction. Results showed that the ultrasonic treatments led to decrease in viscosity of amylose solutions, scission of amylose chains, and narrowing of size distribution of amylose molecules, which gave rise to smaller ANPs with more uniform size. The effect of the ultrasonic treatments on crystalline structure of the ANPs was negligible. This study indicates that ultrasonic treatment can be utilized to prepare smaller starch nanoparticles through nanoprecipitation with higher efficiency and lower cost. (C) 2016 Elsevier Ltd. All rights reserved.