Microbial Exopolysaccharide-Based Flexible Bioactive Film with Murraya koenigii Berries’ Extract for Food Packaging: Physico-Chemical, Microstructural, Antioxidant, and Antimicrobial Properties

Abstract

Guar gum–kefiran composite films incorporated with different quantities of Murraya koenigii berry extract (MKBE) were produced by employing the casting method. Substituting 5% (w/w) guar gum (GG) in a film-forming solution with kefiran decreased the water vapor transmission rate to 6.08 mg/cm²/day in guar gum–kefiran composite film (GKM 0) from 6.67 mg/cm²/day in a neat GG film, and the water contact angle (WCA) increased from 78.3° in the neat GG film to 96.83° in GKM 0. Other physical and mechanical properties are also altered due to kefiran and MKBE incorporation. The biocomposite film with 20% (v/v) MKBE, i.e., GKM 20 film, showed the highest antioxidant activity of 90.34% and the highest total color difference (ΔE) value of 49.3 among all biocomposites. DSC analysis results revealed that thermal properties were significantly improved in the biocomposite film. SEM analysis showed that the homogeneous compact polymer structure formed without phase separation in biocomposite films.