Physicochemical characteristic of corn starch nanoparticles obtained by acid hydrolysis method

¹ Bachelor of Food Technology Program, Faculty of Technology, Institute of Technology and Health Bali, Bali, Indonesia
² Department of Agroindustrial Technology, Faculty of Agricultural Technology, Udayana University, Badung, 80361 Bali, Indonesia
³ Department of Food Technology, Faculty of Agriculture Technology, Udayana University, Bali, Indonesia
⁴ Agricultural Engineering and Biosystems Study Program, Faculty of Agricultural Technology, Udayana University, Badung (80361), Bali, Indonesia
⁵ Research Center for Biomass and Bioproduct, National Research and Innovation Agency, Bogor, Indonesia
⁶ Institute for Advanced Studies, 50603 Kuala Lumpur, Malaysia

^* Corresponding email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Native corn starch often lacks the stability and functionality needed for modern formulations. Here, commercial corn starch was acid-hydrolyzed using 2.2 N HCl at 35 °C for 120 h to generate nano-enabled starch (CSNPs) and to probe how selective chain removal alters structure–property relationships. Relative to the untreated control (CS-Control), the hydrolyzed material showed consistently lower in amylose (14.78 → 13.61%), swelling power (17.86 → 16.58%), solubility (19.95 → 14.69%), moisture (10.95 → 8.91%), and protein/fat contents. These shifts indicate preferential cleavage of amorphous, less ordered regions, enabling residual chains to repack via stronger hydrogen bonding. FTIR spectra retained the characteristic starch bands without evidence of new chemistry; a slightly more bonded O–H region and a sharper 1150– 900 cm^-1 fingerprint supported increased order and reduced amorphous content. Morphology evolved from smooth granules to etched, rounded particles with surface debris (SEM), while TEM revealed tens-to- hundreds-of-nanometers fragments that readily aggregate—consistent with DLS detecting sub-micron to micron-scale populations. Overall, acid hydrolysis yielded a more ordered, nano-enabled starch while highlighting an important practical point: nanoparticles are created, but without an added dispersion step they remain partially aggregated. These insights can guide post-processing (when discrete nanoscale behavior is required.