Preparation and characterization of size-controlled starch nanoparticles based on short linear chains from debranched waxy corn starch

• Starch nanoparticles with controllable particle sizes were prepared.
• All nanoparticles displayed a typical V-type crystallinity.
• The nanoparticles had a high relative crystallinity (43.2–49.5%).
• The nanoparticles exhibited a high melting temperature.

Starch nanoparticles (SNPs) with controllable particle sizes were prepared by nanoprecipitation using short linear chains from debranched waxy corn starch. The morphology, size distribution, degree of polymerization, crystal structure, and thermal properties of SNPs prepared with different volume ratio of starch solution to absolute ethanol were investigated by transmission electron microscopy, dynamic light scattering, high-performance size-exclusion chromatography, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy analysis. When the volume ratio of starch solution to absolute ethanol was 10/40 mL/mL, the SNPs had the smallest particle size (20–100 nm) and degree of polymerization. All SNPs displayed a typical V-type crystalline structure and had a high relative crystallinity (43.2–49.5%). Compared with native waxy corn starch, the melting temperature of SNPs was higher and the temperature range was broader.