Preparation of functional Zein/Spirulina protein isolate nanocomposite particles for improved encapsulation of glabridin

Abstract

This study reports the possibility of zein/Spirulina protein isolate (Zein/SPI) nanocomposite particles as a functional carrier for lipophilic bioactives, using glabridin (GLA) as a model. Zein/SPI nanocomposite particles are synthesized using a conventional anti-solvent precipitation process. The combination of zein and SPI occurs because of electrostatic attraction, hydrophobic interaction, and hydrogen bonding. With an optimal zein/SPI weight ratio, high encapsulation efficiency and loading capacity of GLA are attained with Zein/SPI nanocomposite particles. GLA is successfully encapsulated in an amorphous form. The presence of SPI improves nanoparticle resilience to aggregation and sedimentation under different environmental conditions. Compared to free GLA, encapsulation enhances GLA stability against ultraviolet light, thermal treatment, and long-term storage. Encapsulated GLA also demonstrates better antioxidant activity than GLA dispersed in water. Additionally, a cytotoxicity study reveals that Zein/SPI nanocomposite particles are highly biocompatible. The in vitro release profile shows a steady and slow release of encapsulated GLA without burst effect. These results suggest that Zein/SPI nanocomposite particles can be used as all-natural carriers for lipophilic and unstable bioactives in food, pharmaceuticals, and cosmetics.