In this work, a supercritical-based process, named Supercritical Assisted Injection in a Liquid Antisolvent (SAILA), has been proposed for the entrapment of an antioxidant, luteolin, in zein microparticles. Zein submicro and micrometric particles, with an average size between 0.26 and 2 mu m, were obtained using ethanol-water mixtures as solvent with composition ranging from 70/30 to 90/10 volume ratio. Then, the experiments for the coprecipitation of zein/luteolin were performed. Using SAILA, zein/luteolin microparticles with a mean diameter of 1.20 +/- 0.20 divided by 1.26 +/- 0.17 mu m and good entrapment efficiencies, up to 82%, were obtained. The coprecipitates were characterized by a homogeneous drug dispersion in the polymer matrix. The antioxidant activity of coprecipitated particles was comparable to the one of luteolin in native state. Coprecipitates showed faster dissolution rate (2 divided by 3 h) with respect to the physical mixture zein/luteolin (20h), with a consequent increase in luteolin bioavailability. (C) 2019 Published by Elsevier B.V.