A coulometric sensor determined the amount of oxygen transmitted through the film into the carrier gas. The oxygen transmission rate was determined for all formulations in duplicate. The permeance (PO2) of the films was calculated according to Equation (2): equation(2) PO2=OTRpwherein: PO2 is the permeance of the

films [cm3 m−2 d−1 Pa−1]; OTR is the oxygen transmission rate [cm3 m−2 d−1]; and p is the partial pressure of oxygen, which is the mol fraction of oxygen multiplied by the total pressure (nominally, 1 atm) in the test gas side of the diffusion cell. The partial pressure of O2 on the carrier gas side is considered to be zero. The oxygen permeability coefficient (P′O2) was calculated as follows: LEE011 research buy equation(3) P’O2=PO2×tP’O2=PO2×twherein:

P′O2 is the oxygen permeability coefficient [cm3 m−1 d−1 Pa−1]; and t is the average thickness of the specimen [mm]. Analysis of variance (ANOVA) was applied on the results using the statistical program Statgraphics Centurion program v.15.2.06 (StatPoint®, Inc., Warrenton, USA) and the Tukey test was used to evaluate average differences (at a 95% of confidence interval). The study ABT-737 in vivo was conducted in two steps: firstly, antimicrobial activities of cinnamon and clove essential oils were evaluated, using the disk diffusion method, against P. commune and E. amstelodami, fungi commonly found in else bread products ( Saranraj & Geetha, 2012). It was possible to quantify the minimum amount of each essential oil necessary to be incorporate in cassava starch films in order to develop films with antimicrobial properties. In the second step, cinnamon and clove essential oils were incorporated in cassava starch films. In preliminary assays, it was noted that the amount of clove essential oil necessary to provide films with effective antimicrobial activity against fungi tested was too high and, therefore, it became

infeasible to obtain films with suitable visual and handling properties. Thus, it was decided to produce the active films with only cinnamon essential oil, since this agent presented more promising results in the first step. Despite initial results of microbiological inhibition were quite satisfactory, indicating an almost complete inhibition of fungi, materials produced showed a compromised surface because films became more and more brittle with the increase of essential oil content in the formulation. To overcome this hurdle, it was necessary to vary the plasticizer content in accordance with the increase of essential oil content in the formulation. Since it is known that it is impossible to make homogeneous suspensions of oil in water (that was used as the solvent of the filmogenic solution), an emulsifier in the formulation of cassava starch films was added in order to avoid a phase separation.