Influence of gallic acid and umbelliferone on structural and functional properties of poly(vinyl alcohol-co-ethylene) films for food packaging

Poly(vinyl alcohol-co-ethylene) (EVOH) based systems containing two different active ingredients (AIs), gallic acid (GA) and umbelliferone (UMB) at 5 wt. % and 15 wt. %, were successfully produced by solvent casting and extrusion. The effects of process techniques, active ingredients presence, content and typology on morphological, thermal, mechanical and optical properties of EVOH based films have been analyzed. In addition, migration and radical scavenging activity and moisture content studies were performed, with the objective of evaluating the effect of gallic acid and umbelliferone on the structural and functional properties of relevant/strategic importance in food packaging sector. Data obtained from optical properties (transparency and colorimetric) investigation underlined that the additions of AIs in EVOH copolymer induced important alterations, whereas migration to food simulants data restricted the use of produced films in contact with fatty foods. The use of GA and UMB clearly induced positive antioxidant activity confirming the useful use of extracts in the food packaging sector.