Synthesis and characterization of pectin & xanthan / zinc oxide biopolymer-based functional films for food packaging

Abstract

With increasing demand for sustainable and eco-friendly alternatives to conventional plastic packaging, this work focuses on the development of biodegradable films derived from natural biopolymers. In this study, a composite film was formulated using xanthan gum and pectin in a 2:1 ratio (xanthan gum:pectin), selected based on their compatibility and ability to form mechanically strong and flexible matrices. Four film formulations — XG-P-ZO, XG-P-C, XG-P-ZO-C, and XG-P (control) — were developed through solution casting followed by drying at ambient conditions, and further analysed by physicochemical, mechanical, and functional tests to determine their suitability for food packaging applications. Moisture content, water vapour permeability, water absorption, and tensile strength were examined under standard test conditions. Among the formulations, XG-P-C exhibited the highest tensile strength (1.366 MPa compared to 0.647 MPa for the control), while XG-P-ZO showed the lowest moisture content (5.02%). Water solubility was lowest in XG-P-C (34.56% vs. 57.50% for the control). Antioxidant activity was measured by DPPH scavenging, which exhibited the best performance in the combined additive film, found to be 89.54%, with incorporation of curcumin and zinc oxide. XRD, SEM, and FTIR analysis were also carried out to determine the nature of the film, surface morphology, and presence of functional groups in the formulated films. However, water vapour permeability results indicated that additive incorporation did not improve vapour barrier performance compared to the control, suggesting the need for further matrix optimization. Thus, from the present investigation, the xanthan gum–pectin composite films with zinc oxide and curcumin exhibited improved mechanical strength, antioxidant activity, and controlled moisture absorption while maintaining biodegradability, and show considerable promise as sustainable active packaging materials for extending food shelf life and reducing environmental impact.