Development of new active packaging films containing bioactive nanocomposites

• The natural extract obtained from brewery residual stream is thermally stable.
• Active packaging films with bioactive compounds were developed by extrusion.
• Active packaging films exhibited antimicrobial and antioxidant properties.
• The use of bionanocomposites improved the effectiveness of the packaging system.
• Active packaging films enhanced oxidative stability of beef during refrigeration.

The aim of this study was to develop and evaluate the effectiveness of active packaging films produced with a natural extract obtained from a residual stream generated during the PVPP cleaning process in the brewing industry after a process of elimination of excess of haze active polyphenols present in beer. The thermal stability of the active phenolic compounds was first established at 100 °C and 200 °C and then incorporated into ethylene vinyl acetate (EVA) and low-density polyethylene (LDPE) films by extrusion. Migration, antimicrobial activity and lipid oxidation tests showed that EVA film was the most suitable for incorporating the natural extract. Finally, EVA film was spiked with 3% and 6% (w/w) of the natural extract or functionalized nanoclays (0.6%, 1.2% and 1.8%). Functionalized nanoclays were prepared by combining untreated montmorillonite and 20% of natural extract. The films spiked with the highest concentrations of extract or functionalized nanoclays provided the best results by retarding both the oxidation of beef samples by around 60% and S. aureus growth. The active films developed in the present study show promise for use in the food industry.Industrial relevanceThe new active packaging films developed in this study with a natural extract obtained from a brewery waste and functionalized nanoclays (prepared with natural extract) showed the capacity to enhance the oxidative stability of beef during refrigeration with respect to control films. The use of functionalized nanoclays improves the effectiveness of the active packaging and minimizes the amount of natural extract required. The use of these active packaging films containing bioactive compounds with both antioxidant and antimicrobial properties could extend the shelf life of minimally processed meat products and should therefore be of great interest in the food industry.