Novel Pickering emulsion stabilized by glycated casein embedding curcumin: Stability, bioaccessibility and antioxidant properties

To overcome the barrier of poor stability and low bioaccessibility of curcumin, a novel food-grade Pickering emulsion was constructed using casein and oligochitosan by transglutaminase (TGase)-type glycation method to deliver curcumin. The effect of glycation on the emulsion's physicochemical properties, stability, antioxidant properties and in vitro digestion behavior was assessed with casein and crosslinked casein as a control. The results suggested that the optimal preparation condition was achieved at an oil/water ratio of 1:25 and a protein concentration of 5 %. It was noted that the Pickering emulsion with glycated casein had the highest curcumin encapsulation efficiency (92.93 %) among those stabilized with unmodified and modified casein and exhibited excellent stability under different environmental stresses. In vitro digestion results demonstrated that glycated casein emulsion significantly delayed the release of curcumin and increased the bioaccessibility of curcumin. Moreover, the resulting curcumin-loaded Pickering emulsions exhibited significant antioxidant activity. This study provides new insights into the glycated casein via TGase-type for preserving hydrophobic compounds in Pickering emulsions, thus improving the application of these nutrients in commercial products.