Unlocking the mechanical, physical, and antimicrobial properties of gelatin-based films via chitosan nanoparticle reinforcement for active food packaging applications

Abstract

The growing ecological concerns over plastic packaging have driven interest in biodegradable film materials. This study evaluates the mechanical, physical, and antimicrobial properties of chicken skin gelatin films reinforced with varying concentrations (0–8%) of chitosan nanoparticles (CNPs). CNPs significantly enhanced the films’ performance, increasing the tensile strength from 1.35 to 5.81 MPa, Young’s modulus from 0.42 to 5.61 MPa, and decreasing the elongation at break from 319.11% to 106.72%. Physical improvement of the films included reduced water vapor permeability (1.81 to 0.33 g mm/m2/h/ kPa), higher opacity (0.94–2.21 absorption (A)·mm˗¹), and elevated melting point (76.20 to 129.50°C). Moreover, water contact angle increased with increasing concentration of CNPs (89.35–123.45°), and water solubility improved from 73.65 to 49.85%. The Fourier Transform Infrared spectra confirmed the presence of Amide A (3,279.76–3,284.07 cm˗¹), Amide I (1,629.23–1,632.36 cm˗¹), and Amide II (1,547.41–1,551.40 cm˗¹). The films also exhibited enhanced antibacterial activity against Escherichia coli and Staphylococcus aureus, as demonstrated by the disc diffusion and time-kill kinetic assays. These findings suggest that improved functionality of the developed films may provide a suitable platform for active food packaging applications.