Fabrication and Characterization of Polylactic Acid/Poly(3‐Hydroxybutyrate) Blend‐Based Active Food Packaging Films Incorporated With Graphene Nanoplatelets and Bergamot Oil

Biopolymers such as poly(3‐hydroxybutyrate) (PHB) and poly(lactic acid) (PLA) have high prospects as sustainable food packaging materials. However, PLA has poor gas barrier properties, while PHB suffers from low elongation at break (EAB) and moderate tensile strength (TS). In this work, PLA/PHB blend films with varying weight ratios (90/10, 80/20, 70/30, and 60/40) were developed by solution casting. Among them, the PLA70/PHB30 blend film exhibited the best TS; however, it showed low EAB. Incorporation of 3 wt% bergamot oil (BG) into PLA70/PHB30 blend films increased EAB from 5.2% ± 1.2% to 30.4% ± 0.8% and imparted antimicrobial and antioxidant properties but decreased TS from 57 ± 0.7 to 45 ± 2.1 MPa. In contrast, reinforcement with 0.5 wt% graphene nanoplatelets (GNPs) increased the TS of PLA70/PHB30 blend films from 57 ± 0.7 to 62 ± 1.9 MPa. Therefore, to exploit their synergistic effects, PLA70/PHB30‐based films with combinational loading of 0.5 wt% GNPs and 3 wt% BG were fabricated. The resulting films (PLA70/PHB30/0.5GNPs/3BG) exhibited TS of 52 ± 2.9 MPa and EAB of 17.3% ± 0.5%. The oxygen and water vapor permeability of PLA70/PHB30/0.5GNPs/3BG films were 8.12 ± 0.45 × 10 −3 g.mm.m −2 .s −1 .atm −1 and 1.52 ± 0.28 g.mm.m −2 .day −1 .kPa −1 , respectively. Additionally, these films exhibited 89.65% ± 1.35% antioxidant activity, 52.7% ± 1.2% and 75.5% ± 1.2% inhibitory action against Escherichia coli and Staphylococcus aureus , respectively, demonstrating their potential for active food packaging.