Abstract
Nanoscale waxy rice starch particles were prepared in compressed hot water, and the effects of the concentration of waxy rice starch dispersion, the pressure and temperature of the compressed hot water on mean particle size and particle size distribution were investigated. Particle size and particle size distribution of the waxy rice starch nanoparticles were measured by dynamic light scattering. Mean particle size was found to depend on the preparation conditions. The smallest average particle size of 150.4 nm was obtained with a starch concentration of 0.1% (w/w), an initial pressure of 3.0 MPa, and a final temperature of 180°C. It is suggested that particle size can be controlled by the preparation conditions. In addition, any sample prepared in compressed hot water tends to have a particle size distribution spanning less than 100 nm. The use of compressed hot water is also effective for preparing waxy rice starch nanodispersion with nanoparticles smaller than 100 nm. Furthermore, we have attempted to determine the reaction field of compressed hot water by the ionic product.
