Comparative study on the in vitro digestion of different lipids in starch-based Pickering emulsions

Abstract

Starch-based Pickering stabilizer has attracted more attentions due to its health-friendly attribute. Lipid digestion in Pickering emulsion is the key to its delivery ability for active substances. Herein, in vitro oral-gastric-intestinal digestions of Pickering emulsions stabilized by starch particles with different oil phases (e.g., coconut, corn, olive, and sunflower oils) were investigated. The highest rate of lipid digestion was coconut oil (25.71 %), followed by olive (12.64 %), corn (11.16 %), and sunflower (8.99 %) oils. The lipid digestibility was influenced by saturation of fatty acids: coconut (91.41 %)>olive (16.58 %)>corn (14.63 %)>sunflower (10.85 %) oils. The increase of starch concentration (0.5 % – 4.0 %, w/w) had positive effects, while the increase of oil fraction (25 % – 70 %, v/v) had negative impacts on free fatty acid release due to the formation of different initial droplet sizes. The microstructures observed using confocal laser scanning microscope indicated that starch-based Pickering emulsion possessed super stability against oral and gastric digestions, which made it a superior delivery system for lipophilic active substances under severe gastric environment. These results may promote the design of functional food emulsions stabilized by starch particles which can regulate digestion of triglycerides.