Résumé
Wheat gluten coated papers containing carvacrol (15wt%) as anti-microbial agent and montmorillonite (0-7wt%) as filler were investigated as anti-microbial controlled delivery systems. The carvacrol losses were followed during the coating process and storage time at 30 infinity C under controlled RH from 40 to 100% RH. Increasing MMT content limited carvacrol losses during the coating process. A mathematical model based on Fick's second law was used to determine the apparent diffusivities of carvacrol from experimental data of kinetic release at 30 infinity C and controlled RH. Diffusivity values varied from 0.143 x 10(-14) m(2)/s (0wt% MMT, 40% RH) to 6.010 x 10(-14) m(2)/s (5wt% MMT, 100%RH) depending on both MMT% and RH. The carvacrol diffusivities increased with increasing RH, and the presence of a high amount of MMT(>= 5wt%) accentuated the RH-induced effect. Specific aggregated structure was evidenced by SEM and TEM in the presence of carvacrol and 5wt% MMT creating a preferential pathway for carvacrol diffusion. The anti-microbial efficiency of the MMT-WG-coated papers toward Escherichia Coil was assessed and showed that the antimicrobial effect was related to the carvacrol diffusivity. The diffusivity coefficients were utilized to optimize the packaging characteristics required to develop an efficient anti-microbial system and were finally validated against Botrytis cinerea.