Size-controlled starch nanoparticles prepared by self-assembly with different green surfactant: The effect of electrostatic repulsion or steric hindrance

To study the control effect of surfactants in the process of formation of starch nanoparticles by self-assembly, different surfactants (sodium dodecyl sulfate (SDS), polysorbate 80 (Tween 80), and sorbitan monooleate (Span 80) were added during the fabrication of waxy corn starch nanoparticles (WCSNPs) and potato starch nanoparticles (PSNPs), and their characteristics were determined and compared. The results showed that WCSNPs with SDS and Tween 80 had smaller particle size (28-35 nm and 15-24 nm, respectively) than that of WCSNPs (50-120 nm). The surfactants significantly increased the dispersion and thermal stability of nanoparticles. Short-chain amylose debranched from waxy corn starch had a lower degree of polymerization than that debranched from potato starch and were easier to retrograde, resulting in higher gelatinization enthalpy of WCSNPs. However, PSNPs were smaller in size and achieved better stability than WCSNPs due to stronger electrostatic repulsion caused by a higher absolute value of zeta potential.