Polyvinyl alcohol/gelatin irradiated blends filled by lignin as green filler for antimicrobial packaging materials

Abstract

The prepared lignin from black liquor of bagasse was added to PVA/Gelatin blends (80/20%) at 5.0 to 20.0 phr concentrations (part per hundred volume of the blend). The prepared PVA/Gelatin-Lignin composites subjected to 5.0, 10.0, 15.0, and 25.0 kGy of gamma irradiation doses. Lignin characterised by dynamic light scattering (DLS), tensile strength (TS) and water absorption. Lignin was 712 to 1106 nm in diameter size. TS of the composites was decreased by lignin content up to 20.0 phr and increases by irradiation dose at 5.0 kGy. The water absorption was decreased and not changed greatly by time after 3 h. After 90 days of exposure in soil burial analysis, the PVA/Gelatin-Lignin blends with (15.0 and 20.0 phr) of lignin at 10.0 kGy are expected to degrade at a slow rate. Thermogravimetric analysis (TGA) indicated that lignin enhanced the thermal stability of composites. PVA/Gelatin-Lignin blends exert highly antibacterial and anti-biofilm activities against food-borne contaminants Gram-positive bacteria, Bacillus subtilis, Staphylococcus aureus, and Gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa where hydroxyl group of lignin as a phenolic compound interact with the bacterial cell causing cell membrane disruption, the infiltration of cell component and ultimately bacterial cell lysis. B. subtilis was mostly affected by lignin at 15.0phr and 10.0kGy to record (inhibition zone of 28.12 mm) and antibiofilm activity (73.6%). It indicted lignin may be used as packaging food materials.