Pickering emulsion stabilized by gliadin nanoparticles for astaxanthin delivery

Gliadin, a plant-based amphiphilic protein, has hydrophilic deficiencies in preparing Pickering emulsions. Herein, konjac glucomannan was introduced to improve the wettability of gliadin, and oil-in-water Pickering emulsions stabilized by konjac glucomannan/gliadin colloidal particles (GKPs) with algal oil as internal oil phase were fabricated. The major force between konjac glucomannan and gliadin was hydrogen bonding and the morphology of GKPs appeared as independently dispersed spheres. The presence of konjac glucomannan changed the conformation of gliadin and improved the wettability of GKPs. When the mass ratio of gliadin to konjac glucomannan was 1:1, the three-phase contact angle (θ) of GKPs reached 91.6 ± 0.6°. The Pickering emulsion stabilized by GKPs showed high storage, centrifugation, pH and ionic strength stability. Meanwhile, konjac glucomannan increased the viscosity of the Pickering emulsion. When the mass ratio of gliadin to konjac glucomannan was 1:1, the bioaccessibility of astaxanthin reached 22.37 ± 0.62%, which was 4.5 times higher than that of astaxanthin in pure oil. Thus, Pickering emulsion stabilized by GKPs is a promising delivery system for astaxanthin in the food industry.