Preparation and physicochemical characterization of coix seed starch nanoparticles

In order to provide theoretical basis for the application of coix seed starch nanoparticles (SNPs) and their application in food colloids as Pickering emulsion, the structural characteristics of coix seed SNPs were studied by means of dry-heat–acid-solution-assisted nano-precipitation. Coix seed SNPs were prepared by dry-heat–acid-solution-assisted nano-precipitation in an alkali soluble system (D-A-SNPs), and the structural characteristics of D-A-SNPs were studied in terms of particle properties, molecular properties, crystallization properties, and thermal properties. The results of particle characteristics show that the D-A-SNP particles are more uniform, coalescence, and have an obvious layered structure. With the increase in hydrochloric acid concentration, reaction time, and reaction temperature, the tendency of the particle size of coix seed SNPs decreases first and then increases, and the particle size prepared under treatment conditions (3%, 12 h, 70°C) is the smallest (32.5 nm). In addition, the order, molecular weight, relative crystallinity, and thermal stability of D-A-SNPs decreased.