Effect of dialysate type on ultrasound-assisted self-assembly Zein nanocomplexes: Fabrication, characterization, and...

This study aims to investigate the effect of the dialysate type on the properties of nanocomplexes. Nanocomplexes of zein-sodium caseinate-curcumin (ZNC) and zein-gum arabic-curcumin (Z-G-C) were prepared by ultrasound-assisted dialysis using salt solutions of different concentrations (Na⁺ and Ca²⁺; 2 - 10 mM). With increasing Na⁺ concentration, the overall particle size of ZNC and Z-G-C decreased first and then increased. The Ca²⁺ concentration did not affect the particle size of ZNC and Z-G-C, with good storage stability. The encapsulation efficiency of ZNC decreased significantly from 72.3 ± 6.2 % to 59.8 ± 8.6 % with increasing Na⁺ concentration, while that of Z-G-C increased first and then decreased. The encapsulation efficiency of Ca²⁺ treated ZNC nanoparticles was higher than that of Na⁺ induced nanoparticles. Ca²⁺ did not affect the encapsulation efficiency of Z-G-C nanoparticles. Fluorescence spectroscopy analyses, CD, FTIR, and XRD showed Na + and Ca²⁺ dialysis modified the secondary structure of ZNC and Z-G-C through adding hydrogen bonding and electrostatic interactions. Na⁺ and Ca²⁺ improved the thermal stability of Z-G-C and reduced the thermal stability of ZNC. After encapsulating curcumin, the crystallinity of ZNC and Z-G-C induced by Na⁺ and Ca²⁺ decreased to 45.9 % - 63.9 %, and the amorphous area increased. The above results indicated that Ca²⁺ dialysis could increase the encapsulation efficiency and thermal stability of the nanoparticles, and improve the loading characteristics of zein nanoparticles. The Z-G-C nanoparticles induced by Na⁺ and Ca²⁺ showed better thermal and storage stability.