Storage and digestion stability of encapsulated curcumin in emulsions based on starch granule Pickering stabilization

Stability and loss of encapsulated curcumin was investigated in starch granule stabilized Pickering emulsions. Heat treated and non-heat treated Pickering emulsions have been studied during storage, and during simulated oral, gastric and intestinal in vitro digestion. The amount of retained curcumin in Pickering emulsions was characterized based on spectrophotometric measurements as a function of time. Physical stability of emulsions was characterized using light microscope and light scattering particle size analyzer. Pickering emulsions showed good encapsulation efficiency (∼ 80%) and good stability. Heat treated Pickering emulsions showed better encapsulation stability than non-heat treated Pickering emulsions during 24 h storage (78.2% vs. 38.3%), and during oral (95.3% vs. 69.6%) and intestinal (86.3% vs. 40.2%) simulated in vitro digestions. In the case of simulated gastric in vitro digestion, there was no statistically significant difference in the curcumin content between non-heat treated (86.2%) and heat treated (82.4%) emulsions (P > 0.05). Moreover, comparing the physical stability of emulsions during simulated in vitro intestinal digestion with and without bile salts, it was shown that samples with bile salts showed a larger extent of changes, and these changes were more gradual in heat treated samples. Overall, this study demonstrates that Pickering emulsions stabilized with quinoa starch granules have a potential for effective delivery of bioactive compounds such as curcumin.