Development of Double-Layer Active Films Containing Pomegranate Peel Extract for the Application of Pork Packaging

Nature extract is one of the most important additives in active food packaging. In this study, the mono and double-layer active films containing pomegranate peel extract (PPE) were prepared and their effects for pork stored under refrigeration were evaluated. With 1.5% of PPE as an active agent and polyethylene (PE) resin as a matrix, PPE-PE monolayer active packaging films were prepared by the extrusion blow molding process. With PPE-PE active film as the internal layer film, two double-layer active films such as PPE-PE/polyethylene terephthalate (PET) and PPE-PE/polypropylene (PP) were obtained. The characterizations of mechanical, optical and barrier properties of PE, PE/PET, PPE-PE, PPE-PE/PET and PPE-PE/PP films were determined. The addition of PPE increased elongation at break from 115.85-178.05%. Effects of pork packaged by these active films stored at refrigeration (41C) were evaluated, based on total volatile basic nitrogen (TVB-N), total viable counts (TVC), pH, TBA and drip loss. By day 6, the TVC of pork samples packaged by PPE-PE, PPE-PE/PET, PPE-PE/PP and PE/PET films, respectively, were 5.78, 5.49, 5.58, 5.72 log(10) CFU/g, compared to TVC of pork sample in PE film, 6.54 log(10) CFU/g, which showed PPE-PE/PET and PPE-PE/PP films had good antibacterial effects. These active films delayed the changes of drip loss and sensory score, and retarded the changes of TVB-N, TBA and pH value, especially PPE-PE/PP and PPE-PE/PET films. The results indicated that PPE-PE/PP and PPE-PE/PET active films could extend pork shelf life better than PPE-PE films which could extend pork shelf life by 3 days. Practical ApplicationsActive packaging provides an additional and final barrier that can prevent the corruption effectively. Polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) are well-known packing material for their excellent physical and chemical properties. We blend the pomegranate peel extract (PPE) with PE and prepare the active film by extrude blow. It is a potency to prepare active film in factory not only in laboratory. This work has studied mechanical, optical and barrier property of the active film, and the actual preservation effect of active packaging. The comprehensive characterization of the film would present more valuable information for practical application.