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 relevance: The newactive 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.