Food-grade olive oil Pickering emulsions stabilized by starch/β-cyclodextrin complex nanoparticles: Improved storage stability and regulatory effects on gut microbiota

The beneficial effects of olive oil consumption make it be one of the leading healthy edible oils worldwide. However, the water insolubility and oxidation of olive oil hinder its applications. In this study, food-grade oil-in-water olive oil Pickering emulsions (OOPEs) stabilized by hybrid starch/β-cyclodextrin nanoparticles (starch/β-CD NPs) was developed and characterized. The starch/β-CD NPs concentration and oil phase fraction had a significant influence on the droplet size, zeta potential and storage stability of emulsions. Confocal laser scanning microscopic observation revealed that the starch/β-CD NPs mainly located at the interface of oil droplets, forming a network structure to stabilize emulsions. Rheological analysis indicated the shear-thinning behavior and gel-like structure of starch/β-CD NPs stabilized OOPEs. Additionally, the obtained OOPEs remarkably improved the oxidative stability and storage stability by inhibiting the lipid oxidation compared to pure olive oil. Furthermore, animal experiments indicated that OOPEs modulated the gut microbiota in mice with an enhanced richness and diversity, resulting in an increased abundance of health-promoting bacteria. Notably, high-dosage OOPEs significantly decreased the ratio of phyla Firmicutes/Bacteroidetes. These findings could facilitate the development of olive oil Pickering emulsion with excellent stability and health effects on gut microbiota for applications in foods.