Production of active PET films: Evaluation of scavenging activity

The current trends in packaging technology are focusing on the development of functional materials that interact with the environment and with the food, playing an effective role in the preservation of quality. In particular, the so-called active packaging technologies were developed as a response to the market needs for minimally treated foodstuffs, in order to preserve their freshness and flavours by regulating the gas composition of the packaging headspace through active scavengers. One of the most promising approaches for this technology is the incorporation of active scavengers into a polymeric matrix. Nevertheless, the design and the production of a functional and efficient active flexible package can be difficult to realize because of the complexity of the system. This work was thus focused on the production and the analysis of monolayer polyester films containing an oxygen scavenger. The active film was obtained by adding the active phase into a polyethylene terephthalate matrix during the extrusion process. The barrier properties of the films were investigated by means of conventional permeability measurement, to assess their activity with respect to oxygen. Additionally, the oxygen absorption of the active samples was analysed by an innovative oxygen meter system, in order to determine their scavenging capacity and reaction kinetics. The analysis of colour was carried out on packaged fresh apple slices, to verify if the active films produced were able, to limit the oxidation processes on a sensitive food. Finally, the optical properties of the samples were investigated through haze measurements. Copyright (C) 2007 John Wiley & Sons, Ltd.