Development of PVA/EVA-based bilayer active film and its application to mutton

This study aimed to develop a bilayer active film by using polyvinyl alcohol (PVA)/ethylene-vinyl acetate copolymer (EVA) and antioxidant essential oils. The effect of the bilayer active film on the quality and shelf-life of mutton was investigated. PVA laminated material was considered to improve the barrier capacity, while essential oils incorporated into EVA laminated material conferred antioxidant and antimicrobial activity. The effect of the addition of essential oils on the film by mechanical properties, oxygen permeability, scanning electron microscopy (SEM) image, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) was investigated. Releasing of active compound into mutton and antioxidant activity was investigated to evaluate the films. The antibacterial effects of bilayer active films were subsequently evaluated based on the antibacterial properties of active film and Total viable counts (TVC) of mutton. Microbial community structure in the mutton of different packaging was analyzed by Illumina MiSeq sequencing. Based on total volatile basic nitrogen (TVB-N), the shelf life of mutton was tested. The results showed that the active compound improved flexibility and ductility of active PVA/EVA films. The results also showed a high release of OEO (21.99 mg/kg) and TTO (17.96 mg/kg) as well as high antioxidant and antimicrobial efficiency of PVA/EVA films with essential oils. High-throughput sequencing has shown that the addition of OEO and TTO can reduce the type of dominant bacteria, reducing Acinetobacter by 15.8% and 15.55%, respectively. The release test of active compounds into the mutton showed that the higher contents of the active compounds released, the more microbial proliferation limited, thereby it effectively retarded the increase of TVB-N, which extended the shelf life of mutton by 5–6 days.