Evaluation of antioxidant properties of new active polymers

Active packaging by radical scavenging of the free radical species involved in the biochemical degradation of food is an innovative way to extend the shelf-life of a food product. Current drivers such as consumer’s demand for safer, “healthier,” and higher-quality foods have led to the development of new packaging materials which contain natural extracts. This kind of materials could act as free radical scavengers and thus permit to avoid the use of synthetic and dangerous for the human health antioxidant. In this work, multilayer polymeric materials of different types containing natural extracts of ginger, rosemary and green tea available in the market have been produced and tested. Production was carried out using technologies that could be compatible with the processes used at industrial level. For the test, the scavenging power of the materials was evaluated analysing the quantity of scavenged radicals from a gaseous stream containing in situ produced •OH radicals. The antioxidant power was also evaluated measuring the degradation rate in samples of fried potato chips packed with the materials produced by carrying out TBARs (thiobarbituric acid reaction system) assay. Finally, with the available data, an analysis of the compositions of the materials before and after the oxidation due to the absorbed •OH radicals was carried out, to understand which compounds, belonging to the natural extracts, was responsible of the observed scavenger action.