Eco-Friendly Antimicrobial Food Packaging Films Based on PVA/Starch/Glycerol Blended with Frankincense Ethanolic Extract

Abstract The development of biodegradable packaging materials is a critical research priority driven by the environmental damage caused by non-degradable petroleum-based plastics. In this study, eco-friendly active packaging films were fabricated by incorporating varying concentrations of frankincense ethanolic extract (0-0.5 g per 50 g film-forming solution, samples AR-01 to AR-06) into a PVA/starch/glycerol matrix (70:30 wt/wt PVA/starch, 10 wt% glycerol). Structural and morphological characterizations were performed by FTIR, XRD, SEM-EDX, and TGA/DSC. SEM analysis demonstrated that increasing extract concentration progressively improved film homogeneity: the control film (AR-01) exhibited a rough, irregular surface, whereas AR-06 (0.5 g extract) showed the smoothest morphology, validated by a shift in O-H band position in the FTIR spectrum and a reduction in XRD peak intensity from AR-02 to AR-06, consistent with reduced crystallinity through hydrogen bonding interactions. TGA showed that at 350°C, AR-06 retained 42% residual mass compared with 38% for the control. Water absorption capacity (WAC) decreased from 81.6% in the control (AR-01) to 57.4% in AR-06, reflecting increased hydrophobic character of the matrix at higher extract loading. Tensile strength and elongation at break increased concurrently from 2.752 MPa/6.241% (AR-01) to 3.941 MPa/10.235% (AR-06). Antimicrobial testing against Pseudomonas aeruginosa and Bacillus subtilis confirmed that AR-06 produced the largest zones of inhibition among all formulations. A food spoilage test using pasteurized milk sealed at 25°C for 48 h showed that AR-06 maintained a pH of 7.0 versus 6.0 for the unsealed control, with no visible signs of spoilage. Soil burial tests confirmed progressive biodegradation, with AR-06 exhibiting the highest weight loss after four weeks. These results demonstrate that frankincense ethanolic extract functions as a multifunctional additive in PVA/starch/glycerol blends, simultaneously reinforcing mechanical integrity, improving moisture resistance, and conferring antimicrobial activity.