Encapsulation of β-carotene in wheat gluten nanoparticle-xanthan gum-stabilized Pickering emulsions: Enhancement of carotenoid stability and bioaccessibility

β-carotene was encapsulated in Pickering emulsions stabilized by biopolymer particles formed by wheat gluten nanoparticles (WGN) or wheat gluten nanoparticle-xanthan gum (WGN-XG) complexes. The WGN-XG emulsions had larger initial mean particle diameters (23.9 μm) than the WGN ones (9.4 μm), but they were still stable to aggregation over a wide range of pH values (4–8) and salt levels (0–1000 mM NaCl). They were also effective at protecting β-carotene from chemical degradation during storage, with around 94.3% and 70.1% of the carotenoids being retained after one-month storage at 25 and 37 °C, respectively. WGN-XG and WGN emulsions were both stable to thermal sterilization. An in vitro digestion experiment showed that β-carotene had a higher bioaccessibility in the WGN-XG emulsions than in the WGN ones. These results may facilitate the design of Pickering emulsions with high stability for nutraceutical delivery in food and supplement products.