Preparation and regulation of starch nanoparticles based on amino starch

This study reports a method for synthesizing starch nanoparticles (SNs) using amino debranched starch (AS) and surfactants, employing an ionic crosslinking combined crystallization approach assisted with ultrasonic. AS was synthesized via silane coupling reaction of amino silanes and debranched corn starches with varying amylose contents. Fourier transform infrared spectroscopy confirmed successful silane coupling, with waxy corn starch demonstrating the highest modification efficiency (AWCS, nitrogen content of 2.09%, w/w) and which was choose to prepare SNs. The size and zeta potential of SNs were ranged from 10 to 1000 nm and - 15 to 23 mV, respectively, which modulated by the pH of the AWCS solution, temperature, SDS concentration, and surfactant types. The results indicated that increasing SDS concentration and pH led to an increase in SNs size. Conversely, elevating the AWCS solution temperature diminished the spontaneous aggregation of AWCS, thereby reducing SNs size. This was resulted from the balanced forces among hydrophobic interactions, electrostatic repulsion, hydrogen bonding, and ionic crosslinking of the AS solution. XRD results revealed that the retrogradation process of AWCS was significantly restricted with the increase of pH and temperatures. SDS also inhibited the crystallization of the AWCS, whereas the effect decreased with the increase of the SDS dosage. It was concluded that SNs formation was mainly depended on the ionic crosslinking reaction. This study provides a bottom-up approach for the preparation of SNs with controllable size and zeta potential which exhibits advantages of low energy input, mild condition and easy processing.