CONICET | Buscador de Institutos y Recursos Humanos

A key step in the rate of duodenal lipolysis is the removal of lipolysis products formed at the oil-water interface that are known to inhibit lipids digestion. One of the main roles of bile salts (BS) in duodenal fluid is to solubilize different lipidic products, but predominantly fatty acids (FA), by forming mixed micelles that function as a transport vehicle to deliver FA to the apical membrane of enterocytes for their absorption. Thus, the evaluation of the capacity of duodenal fluid to solubilise fatty acids may allow to know how to regulate this step and manage emulsion composition to influence intestinal absorption. To this end a turbidimetric method was developed that was further validated by particles size analysis (DLS) and oiling off determinations. Oleic acid was used as a reference FA. The saturation limit of the simulated duodenal fluid (0.5% wt BS) was evaluated by a steep increase of turbidity upon stepwise addition of oleic acid. At this point particles grew and excess of lipid oiled off. DLS allowed the study of the structural evolution of micelles, vesicles and droplets.The addition of Tween80 as exogenous surfactant in the range 0.5 ? 1.5 % wt, increased the oleic acid content in the aqueous duodenal phase four times. This favorable effect was due the ability to solubilize oleic acid by itself (about half the capacity of BS). Nevertheless, a negative deviation (20 ? 30 %) from ideality was observed in BS-Tween80 mixtures. It can be concluded that the presence of this non ionic surfactant could strongly contribute to the removal and transport of FA.The developed method offers a new possibility for a better understanding of the mechanisms involved in the modulation of the lipolysis that could help to rationally select the emulsifiers or stabilizers to formulate emulsions with a controlled FA uptake.