Characterization and evaluation of physicochemical and antimicrobial properties of zein nanoparticles loaded with phenolics monoterpenes

Thymol and carvacrol are antioxidant and antimicrobial phenolic monoterpenes and their efficiency depends on preservation and bioavailability. In fact, the latter factors are their greatest impairment since the compounds tend to degrade during food processing. Current assay prepares zein nanoparticles loaded with thymol and carvacrol and evaluates their stability during storage at 4 degrees C and 20 degrees C, for 90 days, assessing their antioxidant activity, encapsulation activity, polydispersity index and zeta potential, controlled release, antimicrobial activity, characterization by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), dynamic light scattering (DLS) and thermogravimetric analysis (TGA). Loaded nanoparticles were stable in the storage conditions analyzed, with antimicrobial activity for the bacteria studied, controlled release throughout the period (50% in 72 h), without burst effects. Consequently, phenolic monoterpenes showed a strong interaction with wall material and proved zein to be a good coating. Transport mechanisms ranged from Fickian to non-Fickian. Loaded nanoparticles were distinct for pure non-encapsulated compounds, proved by SEM, TEM, and TGA techniques. (C) 2015 Elsevier B.V. All rights reserved.