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

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.

Pickering emulsion stabilized by composite-modified waxy corn starch particles.

The starch-based Pickering stabilizer has attracted more research interest recently, however, its application in food system is limited due to the low digestibility of raw starch particles. In this study, waxy corn starches were modified with octenyl succinic anhydride and then treated by dry heating at 180 °C for 20-60 min. Pickering emulsions stabilized by the composite-modified starch particles were fabricated, the physical stability, rheology property and microstructure of the emulsions were investigated. The results showed that the composite-modified starches maintained granule structure, their gelatinization temperatures and enthalpy significantly reduced after heat treatment (p < 0.05). Compared with native starch, the composite-modified starches had bigger three-phase contact angles and higher in vitro digestibility, while the relative crystallinity decreased from 32.46% to 24.87%. Pickering emulsions stabilized by composite-modified starch particles had long-term stability up to 300 days. The rheology results showed that all emulsions exhibited pseudoplastic behaviors and had higher storage modulus than loss modulus. Moreover, the viscosities decreased when the starch was roasted for 40 and 60 min. The composite-modified starch particles and few starch macromolecules at oil-water interface stabilized the emulsions collectively. These results provide a new strategy for designing an edible Pickering stabilizer.