Eugenol@natural Zeolite Nanohybrid vs. Clove Powder as Active and Reinforcement Agents in Novel Brewer’s Spent Grain/Gelatin/Glycerol Edible, High Oxygen Barrier Active Packaging Films

Following the trend of food waste valorization to produce innovative bio-based materials, this study proposes the conversion of brewer’s spent grain (BSG) into added value edible, high oxygen barrier, flexible, active packaging films via an extrusion molding compression method. Gelatin (Gel) was used as both a reinforcement and barrier agent and glycerol (Gl) as a plasticizer. Eugenol was nanoencapsulated on natural zeolite (EG@NZ), and pure clove powder (ClP) was used as an active agent to obtain BSG/Gel/Gl/xEG@NZ and BSG/Gel/Gl/xClP (x = 5, 10, and 15 %wt.) active films. Both BSG/Gel/Gl/xEG@NZ and BSG/Gel/Gl/xClP films show enhanced tensile, oxygen barrier, antioxidant, and antibacterial properties, and low toxicity and genotoxicity values. All BSG/Gel/Gl/xEG@NZ films presented a higher oxygen barrier, higher total phenolic content (TPC) values, higher antioxidant activity according to a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, higher inhibition zones against Staphylococcus aureus and Escherichia coli, and lower toxicity and genotoxicity than all BSG/Gel/Gl/xClP films. Thus, the superiority of the nanoencapsulated EG in NZ as compared to the physical encapsulated EG in ClP is proved. Briefly, BSG/Gel/Gl/15EG@NZ active film exhibited ~218% higher tensile strength, ~93% higher TPC value, and ~90% lower effective concentration for a 60% antioxidant activity value (EC60) as compared to the pure BSG/Gel/Gl film. The zones against S. aureus and E. coli were 45 and 30 mm, respectively, and the oxygen barrier was zero. The use of this film extended the shelf life of fresh minced meat by two days and exhibited the high potential to be used as active packaging material.