An innovative approach to efficiently produce starch nanoparticles: Leveraging the full potential of ball-milling technology

Abstract

The compact outer shell of starch granules impedes the efficient production of starch nanoparticles. Grinding in a ball mill can break down this shell, enabling hydrolysis that yields higher nanostarch production under milder conditions than previously reported. This research examines how controlled grinding in a planetary ball mill over a wide range of milling times (5 minutes to 24 hours) affects the morphology of both native and waxy starches, and explores neutral and acid-catalyzed hydrolysis for efficient nanostarch production. As grinding time increases, the particle size gradually decreases and the particles assume a yellowish hue. Even short grinding durations (5–30 minutes) can significantly deteriorate crystallinity, reducing it to approximately 0%, while simultaneously increasing water sorption capacity to 10.97%. Controlled grinding facilitates the creation of both crystalline and amorphous nanoparticles. To produce starch nanocrystals (SNCs), we combined short-term grinding (15–60 minutes) with long-term acid hydrolysis (4–20 hours) of waxy starch. Specifically, after 15 minutes of grinding and 16 hours of sulfuric acid hydrolysis, we successfully produced SNCs in the characteristic parallelepiped shape. We achieved a 42.5% yield with shorter acid hydrolysis times, surpassing previous reports. The anisotropic phase separation in starch suspensions is a good indicator of SNCs at high concentrations.