Abstract : This thesis concerns β-carotene (βC) encapsulation in lipid nanocapsules (LNCs) in food grade conditions to improve its bioavailability. First, in vitro studies demonstrated that the combination of bile acids and pancreatic enzyme destabilised LNCs structure. NCLs disruption might make βC accessible to intestinal absorption thanks to the presence of micellar type structures. Then, LNCs interface rheological and electrochemical modelling, performed by tensiometry and zetametry, revealed that βC inclusion in LNCs did not influence LNCs interfacial properties. Afterwards, a study on a model matrix (complex food emulsion) showed that encapsulation protect βC from oxidation and enhanced its antioxidant potencies. Finally, in vivo studies on rats revealed that encapsulation of a radiolabelled component enhanced its intestinal absorption. These particles should improve βC bioavailability thanks to its solubilisation in NCLs lipid core end the fine dispersion of lipid fraction.