4. Conclusions
A new innovative procedure to incorporate an antimicrobial agent in a multilayer active material has been described for the first time in the present study. Using this new methodology an efficient antimicrobial material containing cinnamon essential oil has been prepared, showing antimicrobial activity in both inoculated culture media (in vitro) and tomato puree (in vivo). Moreover, migration assays carried out confirmed that the major compound of CO, cinnamaldehyde, is progressively released from the active material in high concentrations. The results obtained suggest that the new procedure might be used to prepare active packaging multilayer materials for active packaging without a significantly increase in the cost of production. It can be pointed out that the chemical composition of the adhesive, used here as vehicle for antimicrobials in the multilayer system, is critical to get the reported antimicrobial activity. Besides, this technology might be used to control the release of the active agents by using inner laminate materials with appropriate thickness, chemical composition and structure.
Migration assays have also indicated the degradation of cinnamaldehyde in the food simulant over time, highlighting the need to carry out migration assays to assess the correct action and the safety of the active materials. Fortunately, in this case the main degradation compound has also antimicrobial activity and it is included as flavouring compound in the food additive list.