Encapsulation of carvacrol into ultrafine fibrous zein films via electrospinning for active packaging

In the present study, zein ultrafine fibers plasticized with tributyl citrate (TBC) were produced via electrospinning according to the central composite design with two independent variables, namely zein concentration (31.2-36.8%, w/v) and carvacrol level (0-8.2%, w/w). The changes in morphology, structure, encapsulation efficiency, thermal, mechanical and water vapor barrier properties of electrospun nanofibers with respect to the independent variables were investigated. The average diameter of zein fibers ranged between 103 +/- 35 and 217 +/- 47 nm. The encapsulation efficiency of carvacrol varied from 40 +/- 1.9 to 81 +/- 1.7%. Carvacrol loaded nanofibers had better thermal stability than zein fibers without carvacrol. Zein fibers with TBC exhibited higher tensile strength than those of pure zein fibers. The tensile strength of films was affected by the linear effect of both zein and carvacrol concentrations and interaction between them. Among fibrous films, a decreasing trend in WVP was observed with increasing carvacrol at low zein concentrations.