ORIGINAL PAPER Superior antioxidant polymer films created through the incorporation of grape tannins in ethyl cellulose Kenneth J. Olejar • Sudip Ray • Arianna Ricci • Paul A. Kilmartin Received: 30 June 2014 / Accepted: 11 September 2014 / Published online: 18 September 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract Agro-wastes represent an abundant and economical source of antioxidant compounds. Extrac- tion and incorporation of antioxidants from these compounds into ethyl cellulose films provides the basis for an active packaging material. Grape tannin extract (GT) incorporation into ethyl cellulose results in hydrogen bonding between polyphenols and ethyl cellulose strands, which allows for the polyphenols to remain active and to be securely incorporated. Incor- poration of 0.5 % GT in ethyl cellulose produced a significant increase (p \ 0.01) in antioxidant activity while not altering physical or mechanical properties. A higher loading of GT at 3.0 % into ethyl cellulose resulted in further improvement in antioxidant activity (12-fold), while a slight decrease in the tensile properties was noted due to the plasticizing effect of GT as a consequence of disruption of the intermolec- ular hydrogen bonding. Keywords Antioxidant  Grape tannin  Ethyl cellulose  Packaging  ABTS Introduction Over the last few decades, polymeric materials have emerged as a cost effective, flexible solution for numerous applications in materials and chemical processing industries, as well as commodity goods. According to a recent market analysis, 288 million tons of plastics were produced worldwide in 2012 (PlasticsEurope 2013). One of the major application areas of these materials is in the food-packaging sector and the demand for plastics in this area is expected to increase. However, the consumer is influencing the production of plastics by requiring them to be ‘‘green’’ with regards to environmental impact, and in the case of packaging, to improve the shelf-life and safety of the products contained. As a result of these influences, the plastics industry has turned to the development of active polymers that incorporates natural components. Active polymers as packaging materials can protect foodstuffs through several mechanisms, including the provision of a general barrier from the environment, but can also impart antioxidant activity. The antioxi- dant barrier can protect the contents from reactive radicals in the environment or those that may be generated in the foods themselves. Reactive species, such as reactive forms of oxygen, can increase the rate of food spoilage as well as alter flavors and appearance, thus shortening shelf-life (Bradley and Min 1992). The grape and wine industry produces a readily available agro-waste, which is high in antioxidant K. J. Olejar (&)  S. Ray  P. A. Kilmartin School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand e-mail: kole917@aucklanduni.ac.nz P. A. Kilmartin e-mail: p.kilmartin@auckland.ac.nz A. Ricci Department of Agricultural and Food Sciences (DISTAL), University of Bologna, Piazza Goidanich 60, Cesena, Italy 123 Cellulose (2014) 21:4545–4556 DOI 10.1007/s10570-014-0447-4