Properties of Solvent Cast Polycaprolactone Films Containing Pomegranate Seed Oil Stabilized with Nanocellulose

Abstract

The increase of consumer demand for using natural products and reducing the use of non-compostable packaging materials have encouraged research on biodegradable polymers including natural components such as essential oils. Pomegranate seed oil (PSO) has active properties such as antimicrobial and antioxidant activities. The aim of this study was to prepare active polycaprolactone (PCL) films by using PSO. PCL films including PSO emulsions (5-30%), which were stabilized with nanocellulose (NC) particles, were prepared by casting method. The physical and active properties of PCL films were determined by means of water vapor permeability (WVP), mechanical properties, optical properties, release behaviour, and potential antimicrobial activity. The WVP values of PCL films was lower when incorporated with NC-stabilized PSO emulsions. The incorporation of PSO into PCL films in the form of NC-stabilized emulsions significantly reduced the transmittance and lightness values, which resulted in an increase in opacity. In the release tests, the slower release of PSO was observed for NC-stabilized films. The stabilization of PSO with NC showed to be less effective when high concentrations of oil (30%) were used. Film samples showed potential antimicrobial activity against Escherichia coli, and Listeria monocytogenes, however, a clear zone of inhibition around the film samples was not detected. Results also suggested that the antimicrobial effect was dependent on two important factors: the release behaviour of PSO through the film samples and, the direct interaction between PSO and microorganisms. These results showed that the combination PCL films and PSO stabilized with NC could be an interesting approach in active packaging technologies.

Keywords

• active packaging film
• biodegradable
• nanocellulose
• polycaprolactone
• pomegranate seed oil