Contribution of phosphorylation modification by sodium tripolyphosphate to the functional properties of hollow zein...

In this study, hollow zein nanoparticles (HZn) have been prepared by Na₂CO₃ as a sacrificial template, and phosphorylated hollow zein nanoparticles (PHZn) have been further prepared with sodium tripolyphosphate (STP) incorporation. The results indicated that HZn exhibited a smaller particle size in comparison to solid zein nanoparticles (SZn), which consequently led to a higher degree of phosphorylation for HZn when equivalent amounts of STP were incorporated. As phosphorylation increased, the zeta potential, free amino content, and free sulfhydryl content of HZn decreased, attaining the lowest values of -53.2 mV, 0.134 mmol/g, and 14.36 µmol/g, respectively. Scanning electron microscopy, fourier transform infrared spectroscopy, circular dichroism spectroscopy, and intrinsic fluorescence spectroscopy measurements showed that PHZn was more denatured than SZn. This series of changes contributed to the improvement of the functional indicators. Thus, compared to SZn, the functional characteristics of PHZn at the highest phosphorylation level exhibit significant improvements in several aspects: solubility increased from 21.88 % to 43.45 %; excellent storage stability for at least 3 weeks at room temperature; enhancements in emulsification activity and emulsification stability by 118.63 m²/g and 59.54 %, respectively; increases in foaming capacity and foaming stability by 2.73 and 1.22 times, respectively; and improvements in puerarin encapsulation efficiency and loading capacity by 17.10 % and 3.42 %, individually. These findings indicate that the implementation of hollow preparation techniques and the incorporation of STP can enhance the functional properties and broaden the potential applications of zein nanoparticles.