Development of multilayer corn starch-based food packaging structures containing -carotene by means of the electro-hydrodynamic processing

An antioxidant multilayer structure based on thermoplastic corn starch (TPCS) was developed by means of the electrohydrodynamic process of electrospinning. Firstly, the effect of adding electrospun outer layers made of polycaprolactone (PCL) on the microstructure and barrier properties of a thermoplastic corn starch (TPCS) film was evaluated. Secondly, -carotene was encapsulated into PCL matrices by means of the electrospinning technique and these hybrid structures were directly electrospun as coating layers onto both sides of a TPCS based film, thus giving rise to an antioxidant multilayer packaging structure. The influence of -carotene on the structural, antioxidant, barrier and optical properties of the developed multilayer systems were studied. Barrier properties of the TPCS based films were improved by the addition of the electrospun coatings. However, -carotene addition did not improve barrier properties as compared to their counterparts prepared without the active compound, although both permeability values remained up to 75% lower than those obtained for the pure TPCS. On the other hand, the stability of the -carotene was studied using colour assays and the antioxidant activity after the film-forming process. Results showed that the stability of the -carotene was greatly affected by the annealing step (used to improve the adhesion between layers) even when it was encapsulated into the electrospun PCL layer.