Resumen
Biodegradable polymers are gaining interest as antimicrobial carriers in active packaging. In the present study, two active films based on chitosan (1.5% w/v) and methylcellulose (3% w/v) enriched with natamycin were prepared by casting. The antimicrobial?s release behavior was evaluated by immersion of the films in 95% ethanol (v/v) at different temperatures. The natamycin content in the food simulant was determined by reversed-high performance liquid chromatography with diode-array detection (HPLC-DAD). The apparent diffusion (DP) and partition (KP/S) coefficients were calculated using a mathematical model based on Fick?s Second Law. Results showed that the release of natamycin from chitosan based film (DP = 3.61 × 10-13 cm2/s) was slower, when compared with methylcellulose film (DP = 3.20 × 10-8 cm2/s) at the same temperature (p < 0.05). To evaluate the antimicrobial efficiency of active films, cheese samples were completely covered with the films, stored at 20 °C for 7 days, and then analyzed for moulds and yeasts. Microbiological analyses showed a significant reduction in yeasts and moulds (7.91 log CFU/g) in samples treated with chitosan active films (p < 0.05). The good compatibility of natamycin with chitosan, the low Dp, and antimicrobial properties suggested that the film could be favorably used in antimicrobial packagings.