After preliminary results and based on previous work (Souza et al., 2012), proportions of 1.88 for glycerol content/essential oil content; and 0.025 for emulsifier content/essential oil content, were chosen to provide films with good visual and
tactile characteristics. Different results of inhibition were obtained for each essential oil and for each microorganism studied (Table 1). For P. commune, inhibition began with 0.5 g/100 g of cinnamon essential oil solution (diameter: 4 mm) and with 4.0 g/100 g of clove essential oil solution (diameter: 6 mm) and was completed (100% of inhibition) with 2.0 g/100 g ALK inhibitor and 16 g/100 g, respectively. For E. amstelodami, inhibition was completed with only 0.5 g/100 g of cinnamon essential oil solution and began with 4.0 g/100 g of clove essential oil solution (diameter: 14 mm) and was completed with 16 g/100 g. With these results, it can be concluded that cinnamon essential oil was more effective against the fungi selected for this work, since it presented Selleckchem ABT-199 a better inhibition with lower concentration. In this way, cinnamon essential oil was chosen to be incorporated in composite films based on cassava starch. Inhibition areas
yielded by cassava starch film disks with different contents of cinnamon essential oil against each studied microorganism are shown in Table 2. ANOVA indicated that there were significant differences among antimicrobial activity of films with different cinnamon essential oil contents (P < 0.05). As predictable, no inhibition zone against the microorganisms was observed for film Protirelin disks without incorporation of essential oil (control films). Comparing the microorganisms, it can be concluded that E. amstelodami is more sensitive for cinnamon essential oil because its inhibition was greater, reaching approximately 91% of inhibition with the highest concentration used. Fig. 2 shows the inhibition of P. commune caused by active films produced with three different contents of cinnamon essential oil. As expected, a better
inhibition was observed with higher content of cinnamon essential oil ( Fig. 3). Even at minimum concentration applied into the film formulation, cinnamon essential oil showed inhibition against both microorganisms, which was considered an important result since that higher concentrations could imply a sensorial impact, altering the natural taste of the food packaged by exceeding the acceptable flavor thresholds. A great number of studies on the antimicrobial characteristics of films made from starch have been carried out earlier. Nevertheless, no information has been presented about the effect of cinnamon essential oil on P. commune and E. amstelodami, which plays an important role in the spoilage of bread products. Cinnamon essential oil (CEO) release profiles from cassava starch films, for a monitoring period of 2 h, are shown in Fig. 2. Released amounts of CEO varied from (0.88 ± 0.10) mg CEO/g film to (1.19 ± 0.