出版社：Grupo de Pesquisa Metodologias em Ensino e Aprendizagem em Ciências
摘要：With the aim of prolonging the shelf life and preserving the properties of food, active packaging emerged. In this study, poly(butylene adipate-co-terephthalate) films added with 5, 10 and 15 % (m/m) of Melaleuca alternifolia essential oil were prepared by the solution casting technique. The oil was characterized by hyphenated gas chromatography coupled with mass spectrometry (GC-MS) and Fourier transform mid-infrared spectroscopy (FTIR), identifying as major components: aromadendrene, α-guayene, α-terpineol and 2-methylisoborneol. Oil’s antimicrobial activity was evaluated against the bacteria Escherichia coli by disk-diffusion technique in agar medium, obtaining a halo of 15 mm. The mid-infrared spectra of the films, when subjected to a principal component analysis, showed that there was incoporation of oil into the polymer matrix. The increase in the oil concentration increased the water vapor permeability and reduced the film stiffness, evaluated by mechanical tensile tests. It was also found, through thermogravimetry and differential exploratory calorimetry techniques that the incorporated oil did not change: the thermal stability of the polymer (keeping the degradation in a single step), the melting and crystallization temperatures, the degree of crystallinity of the polymer and the enthalpy of fusion. Finally, the film added with 15% (w/w) of oil showed good inhibition against the Escherichia coli bacteria, after 12 days of contact with a sample of mozzarella cheese at 4o C, reducing the inoculated microbial load of 1,08 107 CFU/mL to 2,75 106 CFU/mL, which makes this material a promising antimicrobial active packaging.
