Preparation and characterization of bioactive edible packaging films based on pomelo peel flours incorporating tea polyphenol

Bioactive edible packaging films were developed by incorporating different concentrations (5%, 10%, 15, and 20%) of tea polyphenol (TP) into the pomelo peel flour (PPF) in order to modify the functional properties of the films. The proximate chemical composition of PPF was firstly determined. The PPF based films were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), together with the determination of physical, optical, mechanical, antioxidant and antimicrobial properties of the films. The incorporation of TP significantly improved the antioxidant activity and antimicrobial activity of the films, while induced a decrease in the transmittance, moisture content and elongation at break. Addition of TP at an appropriate level (10% TP) led to stronger intermolecular interactions and more compact microstructure, and thus enhanced the water barrier properties and tensile strength of the films. Potential packaging application was evaluated using soybean oil in an oven at 50 °C for 30 days. The PPF/TP composite film significantly decreased peroxide value (POV) to delay oil oxidation during storage. These results revealed that pomelo peel is a good film-forming substrate and tea polyphenol has a good potential to be incorporated into pomelo peel to prepare biodegradable/edible active films for food applications.