Kinetic stability and cellular uptake of lutein in WPI-stabilised nanoemulsions and emulsions prepared by emulsification and solvent evaporation method

The particle size and lutein encapsulation efficiency of nanoemulsions prepared by emulsification and solvent evaporation method were 68.8 +/- 0.3 nm and 80.7 +/- 0.8%, respectively, whereas they were 147.3 +/- 0.6 nm and 86.3 +/- 0.3% for conventional emulsions. All the emulsions had no change in their particle size during storage (28 days at 5, 20 and 40 degrees C) but their lutein content and emulsion colour decreased, especially at 40 degrees C. The lutein emulsions were analysed using MTT assay on the gut enterocyte cell line Caco-2 and they showed no toxicity as the cell viability was more than 80% at 10 times or higher dilution after 24 h of incubation. However, there was a higher cellular uptake of lutein by Caco-2 cells in nanoemulsions (872.9 +/- 88.3 pmol/mg protein) than conventional emulsions (329.5 +/- 214.6 pmol/mg protein). The results of this study indicated that nanoemulsions can be used as a delivery system to improve the cellular uptake of lutein. (C) 2016 Elsevier Ltd. All rights reserved.