Microstructural characterization of chitosan films used as support for ferulic acid release

Abstract

The influence of natural antioxidants incorporated to biodegradable materials has become a focus of attention in the current food packaging research and development. Chitosan is a functional natural polymer extensively used for tailoring systems or matrices for a different active compound delivery. This work was focused on studying the changes undergone by the chitosan matrix because of the addition of ferulic acid as an antioxidant. Thus, both microstructure and physical properties such as solubility, thermal stability, mechanical and barrier properties were monitored. The addition of ferulic acid caused a decrease in both the moisture content and water vapor permeability, an increase in resistance and a change at the structural level evidenced by TEM. Through FTIR spectra and their relationship with chitosan-based film properties, it was demonstrated that ferulic acid was effectively incorporated in the polymer matrix. The amount of the bioactive compound released from the chitosan matrix to a liquid medium was determined. The delivery profile suggested that the release of the antioxidant agent was controlled by two parallel mechanisms, one Fickian-type and the other associated to the high swelling of the matrix. The antioxidant and UV-barrier properties induced by the addition of ferulic acid turned the chitosan films into a potentially active material to be applied on high-fat foods.