Eugenol incorporation into thermoprocessed starch films using different encapsulating materials

Abstract

[EN] The effect of the incorporation of eugenol on the mechanical, barrier and antioxidant properties of compression moulded corn starch films was studied as well as the release kinetics. Free or spray-dried encapsulated eugenol, using whey protein or lecithin as wall materials and maltodextrin as drying coadjuvant and oleic acid (OA) as a carrying agent, was used. Thermo-processing of the films caused significant eugenol losses (80-65%), which were minimised when microcapsules contained OA. In the films with free eugenol, the compound retention was enhanced through its complexation with starch. Eugenol microcapsules provoked a heterogeneous microstructure in the film matrices, which became less resistant and stretchable, with lower water sorption capacity and improved barrier properties. Encapsulates promoted a faster eugenol release and a greater release ratio at equilibrium, especially when they contained more water-soluble components. An acid medium promoted the release ratio, associated with the progressive partial hydrolysis of the starch matrix.