Desenvolvimento de filmes de pectina contendo nanoemulsões de óleo de copaíba obtidos por casting contínuo

Abstract

The development of active biodegradable films has gained extreme relevance due to the potential of applying these materials in the food sectors and also for sustainability and environmental protection issues. The present work had as its objective the preparation of biodegradable pectin plastics incorporated with copaiba oil for use as active packaging. The films were prepared with different concentrations of copaiba oil in the pectin matrix by continuous casting, an emerging polymer film production technique. The nanoemulsions were characterized for medium size and particle distribution and zeta potential, while the biopolymer films were evaluated by thermal analysis (TG), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), uniaxial traction tests, antimicrobial activity and biodegradation. The increase in mean droplet diameter as a function of concentration and storage time was observed. The zeta potential results revealed that nanoemulsions at time zero were stable. After 72 hours of storage, a decrease in zeta potential was observed. The study of the morphology showed that the pure biopolymers have homogeneous and compact microstructure whereas those with copaiba oil addition had an increase in the roughness as the concentration of oil increased. The spectra of the biopolymers with copaiba oil were similar to the pure pectin film. The results of the mechanical characterization evidenced that the incorporation of the copaiba oil resulted in the gradual decrease of elastic modulus and tensile strength, while increasing the elongation at break. A bacteriostatic effect was observed in the films against Escherichia coli and Staphylococcus aureus. The free compounds of copaiba oil inhibited microbial growth, decreasing the evolution of CO2 in the biodegradation process. The results of this work evidenced the potential of continuous casting for the production of pectin biopolymers incorporated with copaiba oil and thus leading to the development of ecologically correct multifunctional materials and consequently, as an alternative for active packaging.