Emulsion encapsulation in calcium-alginate beads delays lipolysis during dynamic in vitro digestion

We assessed the behaviour of encapsulated oil-in-water emulsions in alginate beads under dynamic digestion conditions to test their suitability for ileal brake activation. A dynamic gastrointestinal digestion system (DIDGI) was used with three consecutive compartments simulating the stomach, duodenum and distal small intestine. Digestive media were collected periodically to follow lipolysis, as well as the solubilisation of absorbable lipid species in mixed micelles. Free emulsions (i.e., non-encapsulated) in absence or presence of empty alginate beads were used as controls. In the free emulsions lipolysis occurred rapidly with micellar solubilisation not rate limiting, which indicates proximal digestion and absorption. Encapsulation of emulsions in calcium-alginate beads delayed lipolysis typically for 3 h by diffusion limitation, after which most probably mechanical disintegration took place. Our findings do not only increase the understanding of the dynamics of lipid digestion, but also directly link to the design of encapsulates (size and mesh size) for long-term weight management strategies.