Preparation and Stability Analysis of Spirulina Polyphenol Composite Nanocapsules

To improve the stability of Spirulina polyphenols through microencapsulation. Two types of microcapsules, Phe-PS and Phe-PS-Zein were prepared by embedding zein and porous starch (PS) in spirulina polyphenols (Phe). The microstructure, stability, antioxidant activity, and in vitro simulated digestion properties of Phe, Phe-PS, and Phe-PS-Zein were compared. The results showed that under the conditions of core to wall ratio of 1:10, temperature of 80 ℃, and magnetic stirring time of 120 minutes, the embedding rate of Phe-PS microcapsules was 60.29%. The encapsulation efficiency of Phe-PS-Zein microcapsules was the highest at core to wall ratio of 1:10, wall to material ratio of 1:1, stirring time of 90 minutes, temperature of 60 ℃, and pH of 7, reached 86.93%. The XRD and XPS spectra indicated that the diffraction peak intensity of the crystal decreased after the addition of zein, which was mainly related to the amorphous structure of zein. DSC analysis showed that the addition of protein as wall material improved the thermal stability of microcapsules. Compared with free Phe and Phe-PS, Phe-PS-Zein showed an increased ability to scavenge DPPH radicals and reduce Fe³⁺ by measuring its antioxidant activity, stability, and in vitro sustained-release effect. In summary, the Phe-PS-Zein particles could serve as an effective delivery carrier for Spirulina polyphenols. The results of this study would be expected to provide a theoretical and experimental basis for the high-value utilization of Phe.