Influence of surfactant tween 20 on antioxidant activity of active biopolymer films

Biopolymer films are biodegradable films produced from natural resources. Beside many benefits, especially from the ecological point of view, they can be used as active packaging materials, acting as matrix for different active ingredients. Lately, natural compounds with pronounced antioxidant and antimicrobial activity have been investigated as alternatives to synthetic ones for preserving food quality. Essential oils represent interesting natural ingredients for active biodegradable food packaging, mainly due to their functional properties. Science is in particular focused on their incorporation into active biopolymer packaging materials, in order to maintain quality and extend the shelf-life of packaged products. However, because of there lyophilic nature, incorporation into film-forming emulsions can be difficult. Non-ionic, hydrophobic surfactants, such as those from the Tween group, have a wide application in synthesis of active biofilms, since they serve as emulsifiers for lipophilic substances. Additionally, they also possess great capacity to dissolve poorly soluble compounds. In this paper, active films based on pumpkin oil cake (PuOC) with 1% of winter savory (Satureja montana) essential oil and 1% of basil (Ocimum basilicum) essential oil, with different concentrations of Tween 20 (1%, 1.5% and 2%), were synthetized and antioxidant activity of obtained films, was examined. Methods used to determine antioxidant activity of films were DPPH radical, reducing power and hydroxyl radical assay. The obtained results show that addition of different concentrations of Tween 20 has more influence on PuOC film activity with winter savory essential oil than PuOC film with basil essential oil. Results showed that with increasing concentration of Tween 20, in PuOC film with winter savory, antioxidant activity increased in all three parameters for measuring. Influence of different concentration of Tween 20 on antioxidant activity of film with basil essential oil was observed in hydroxyl radical assay, where antioxidant activity decreased with increasing concentration of Tween 20.