Solubilization of lipolysis products in mixed micelles is enhanced in presence of bile salts and Tween 80 as revealed by a model study (oleic acid) and emulsified chia-oil

Abstract

In the last few decades, there has been a growing interest in understanding the mechanisms involved in lipid digestion with the purpose of developing strategies to control this complex physiological process. Bile salts (BS) are natural bio-surfactants that play crucial functions in this process and may represent a key strategy to modulate the lipolysis. One of the main functions is the removal of lipolysis products present at the interface of lipid droplets by solubilizing them in BS micelles, thus avoiding the reaction inhibition. However, there are few studies that analyzed the effects that could have the emulsion components on the solubilization capacity of BS micelles. Thus, the main purpose of the present work was to evaluate the impact of a typical food emulsifier (Tween 80) on the fatty acid (FA) solubilization capacity of BS micelles by using a method recently developed, involving a combination of turbidity and dynamic light scattering (DLS) determinations. As FA solubilization into BS micelles may strongly affect the kinetics of lipolysis, the lipolysis of T80-stabilized oil-in-water (O/W) emulsions was also studied. The results showed that a higher concentration of the emulsifier in the duodenal medium causes the lipolysis rate to be maximum for a longer time. The mechanism involved could be the contribution of T80 to increase the solubilization of FA (and possibly other products of the lipolysis) in the duodenal medium, consequently affecting the potential bioavailability of fatty acids.