Enhancement of the intestinal permeability of curcumin using Pickering emulsions stabilized by starch crystals and chitosan

Curcumin is widely known as a health-promoting polyphenol. However, gastrointestinal instability and low intestinal permeability limit its application in foods. To overcome these drawbacks, we fabricated a Pickering emulsion system stabilized by starch crystals and chitosan with the potential for steric hindrance, mucoadhesion, and reversible opening of epithelial tight junctions. During simulated digestion, chitosan-coated emulsions maintained their stability in the mouth and stomach phases, and digested slowly in the intestine phase. Through a simulated absorption test, the permeability of curcumin encapsulated in the chitosan-coated emulsions was enhanced ∼9.5-fold compared to the curcumin solution. Based on the results obtained using fluorescence micrographs and transepithelial electrical resistance of a mucus-covered Caco-2 monolayer, the enhanced intestinal permeability of curcumin was due to the electrostatic mucoadhesion and reversible epithelial tight junction opening effects of the chitosan-coating. Our findings will facilitate the rational design of foods or beverages incorporating food-grade lipophilic bioactives such as curcumin.