β-lactoglobulin peptides originating during in vitro digestion improve the bioaccesibility of healthy oils emulsions by forming mixed bile salts micelles with enhanced capacity to solubilize lipolysis products

Abstract

The study of lipid digestion has increased in recent years in order to elucidate how lipolysis can be controlled as this knowledge can aid to design healthier emulsified foods. Most of the works have attributed the decrease of the extent and rate of lipolysis of protein stabilized emulsions to droplet coalescence during the gastric phase causing a decrease of the interfacial area available for the reaction. Despite the crucial role of BS in lipids digestion, only few works have attributed a decrease of lipolysis to BS-emulsifiers interactions occurring both, at the interface, or in the bulk phase. The present work focuses in understanding the way in which a model milk protein as β-lactoglobulin (βlg), used as emulsifier, interacts with BS micelles under in vitro gastroduodenal conditions, modifying their capacity to solubilize the products of lipolysis and verify if this phenomenon is reflected in the kinetics of lipolysis of olive or chia oil in water emulsions. This work shows that the presence of βlg promotes the bioaccessibility of healthy oils such as olive oil or chia oil, which are sources of bioactive fatty acids. The mechanism involved is mediated by the interaction of the BS micelles with the peptides originated from the gastroduodenal proteolysis of the protein. As a result of this interaction, mixed micelles with a much higher capacity to solubilize the lipolysis products are formed. Therefore the lipolysis can proceed at the highest rate for a longer time.