Avaliação de materiais a base de quitosana para o uso como liberadores de compostos bioativos voláteis

Abstract

The use of volatile biological compounds has gained attention to the agribusiness field due to the increase of the rigor in the international legislation of food imports and the increase of the awareness about environmental contamination. In order to use these compounds, it is necessary to develop materials able to controlled release in order to maintain the active concentrations for a long period. In this sense, new materials that are malleable, biodegradable and low cost have been develop by several researches. For the development of new materials, this work employed chitosan and linter as raw resources, being new releasers developed through physical and chemical modifications. Four materials, Chitosan (Q), Chitosan Ball Cross-linked with Glutaraldehyde Dried by Freeze Drying (QLio), Chitosan Ball with Gold Nanospheres anchored in Nanosilica Crosslinked with Glutaraldehyde Dried by Freeze Drying (QLio_Au) and a Linter Biocomposite with Chitosan crosslinked with Glutaraldehyde and dried under reduced pressure (LQG). The materials were characterized by Infrared Spectroscopy (FTIR), textural analysis (BET) and Thermogravimetric Analysis (TGA), in which important modifications between the materials help to understand their different behavior. The bioactive compounds used for the liberation tests were Ethyl Octanoate (Oc), as a part of the composition of several known pheromones, and Citronella (Ci) for having a chemical structure similar to Oc with a higher electron density , thus providing interesting data of the materials affinity. The liberation-volatile interaction studies showed that volatiles had good interaction with all materials, especially QLio and QLio_Au. Controlled release tests showed that all materials behave as good releasers and have better interaction with compounds capable of perform stronger London interactions.