After drying, all films were placed in a controlled relative humidity of 75% and at ambient temperature of (23 ± 2) °C and stored prior to

testing. Using the pour plate method, inoculums Selleckchem NU7441 (1 mL) of P. commune and E. amstelodami were spread on the surface of Petri dishes prepared with the selected medium for fungi. The inoculums were adjusted to each microorganism to yield a cell concentration of 108 CFU/mL. The minimum inhibitory concentration (MIC) was defined as the lowest essential oil concentration resulting in the lack of visible microorganism growth using the disk diffusion method. Circular disk samples of filter paper (25 mm of diameter) were absorbed with alcoholic solutions of each essential oil at different concentrations: (0.0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0) g/100 g, and placed on the solidified medium surface. Petri dishes were then incubated at (25 ± 2) °C for 5 days and the inhibitory zone was determined measuring its diameter. In order to evaluate the efficiency of each cinnamon essential oil contents incorporated into composite films, circular disk samples of these films were placed, instead of filter paper, on the solidified medium surface. Petri dishes were then incubated at (25 ± 2) °C for 5 days. Antimicrobial agent efficiency was evaluated by the formation of an inhibition zone around the disk samples, which was characterized

Selleck Cabozantinib by surrounding clear areas. To a better presentation of the results, the diameter of inhibition zone of each Petri dish was measured and, knowing the total area of the Petri dish, inhibition results were converted to percentage of inhibition areas. All tests were performed in triplicate, seven days after the

film elaboration. The amount of antimicrobial agent incorporated in cassava starch films was quantified by UV–vis spectroscopy (Spectrophotometer JASCO, model 550, Japan) measuring at 289 nm, corresponding to the maximum absorption wavelength of cinnamon essential oil, and using a pre-determined calibration curve. The release experiments were carried out at room temperature with the films immersed in distilled water (150 mL) for 2 h. After the first 2 h, tested samples were once more immersed in distilled water and a new spectroscopy quantification was done at 289 nm in order to ensure that this Morin Hydrate time was enough to guarantee full release of antimicrobial agent from the films (in this case, the content quantified should be zero). Assays were performed in duplicate. The thickness (t) [mm] was measured using a flat parallel surface micrometer (MITUTOYO Sul Americana Ltda., model 103-137, Brazil, precision 0.002 mm), at five random positions of the films. Small strips (5 mm × 5 mm) of cassava starch films were mounted on aluminum stubs, coated with a thin layer of gold and observed on a Scanning Electron Microscope (Philips, model XL-30 FEG), at an accelerate voltage of 5 kV.