LAUSR

Abstract Intestinal droplet coalescence is central to the lipid digestibility of oil-in-water nanoemulsions. In the present study, a methodology has been proposed to investigate the rheological transformations of nanoemulsions in response to the simulated conditions of small intestinal mechanical forces. The relationship between rheological changes and droplet coalescence phenomenon was probed. Elastic moduli of nanoemulsions attained a maximum at a specific point of digestion time, which was found to be characteristic of the emulsifier used. The onset of droplet coalescence showed evident dependence on the elastic modulus. The above correlation was quantified with an improved empirical model for droplet coalescence frequency. However, droplet coalescence was beyond the scope of rheology and depended on changes in the zeta potential of droplets, which eventually determined the release of free fatty acids. The critical time point was mapped at which the balance of rheological and electrostatic forces on droplet coalescence was altered as the lipolysis proceeds during the simulated small intestinal digestion of nanoemulsions.