Modification of the interfacial structure of droplet-stabilised emulsions during in vitro dynamic gastric digestion: Impact on in vitro intestinal lipid digestion

The in-vitro gastrointestinal digestion behaviour of an oil-in-water emulsion with an interface consisting of nano-sized droplets coated with caseinate particles, referred to as a droplet-stabilised emulsion (DSE), was explored using the human gastric simulator and pH-stat models. A caseinate-particle-stabilised emulsion (PSE) was used as a control, with a similar droplet size distribution and the same composition as the DSE. The nanodroplet-stabilised interface of the DSE was preserved during the first 180 min of gastric digestion. During 240 min, the droplet sizes of the DSE and the PSE increased from 22.71 +/- 1.14 to 63. 34 +/- 6.57 lm and from 17.98 +/- 1.16 to 85.11 +/- 9.35 lm respectively. The small droplet size of the DSE that was released from the gastric phase contributed to slightly higher total free fatty acid (FFA) release (56. 18 +/- 3.55%) than that from the PSE (49.4 +/- 2.67%). The FFA release rate of the DSE (1.21 % min-1) was greater than that of the PSE (1.06 % min-1) during the first 30 min of small intestinal digestion; similar FFA release rates (0.5 mmol s-1 m-2 x 10-4) were obtained for both emulsions beyond 30 min of diges