Solution enhanced dispersion by supercritical fluids (SEDS) was applied for the production of lutein/zein nanoparticles. The effects of the process variables on the morphology, drug loading, entrapment efficiency, and mean particle size of the nanoparticles were investigated. The results showed that the nanoparticles with high drug loading and high entrapment efficiency were prepared by SEDS process. Temperature, pressure, ratio of lutein/zein, and solution flow rate can influence the morphology, drug loading, entrapment efficiency, and the mean particle size of the lutein/zein nanoparticles. The lower temperature and solution flow rate coupled with high pressure, favor smaller and more regular spheres. The initial and overall drug release behavior of the samples was tested. The initial burst release was hardly observed in the nanoparticles processed at 45 degrees C/10 MPa. Furthermore, lutein release profile displayed a near zero-order release, which implied that the nanoparticles played a role in controlled release of lutein. (C) 2011 Elsevier Ltd. All rights reserved.