Ultrasmooth and Uniform Starch Nanosphere with New Microstructure Formation via Microfluidization-Nanoprecipitation Control

Nanostarch has attracted great attention owing to its high biocompatibility, easy availability, low sensitization, small size, and large specific surface area. However, most well-dispersed spherical nanostarches are currently produced under chemical surfactants. Here, we use controllable dynamic high-pressure microfluidization (DHPM) with a nanoprecipitation method to prepare smooth surface and homogeneous starch nanospheres (SNSs). Under the microfluidization condition in a homogenization cycle of x4 and pressure of 100 MPa, the smallest particle size (67.1 nm) of SNSs with excellent dispersibility (PDI 0.307) was obtained. In addition, after DHPM treating, the crystal structure of starch was damaged. Also, V-type crystallinity was observed after nanoprecipitation, and side chains in starch were cut as performed in an inside-out mode to form small starch clusters. Notably, by mechanical forces, the positions of the OH groups of starch glucan rings were greatly motivated in the spectra of FTIR, 1H NMR, 13C NMR, and XPS. They were cross-linked with each other to form new microstructures of -C-O-C- groups. Furthermore, this should be highlighted for the importance of pressure and homogenization cycle conditions in order to prepare bioresource nanomaterials with well-dispersed properties according to food and nonfood applications like delivery systems.