Development of eco-friendly bovine hoof gelatin-cellulose films reinforced with Myrothamnus flabellifolius extract, green-synthesized zinc oxide nanoparticles (ZnO Nps) and β-cyclodextrin nanocomposites.

Abstract

The environmental impact of synthetic polymer and food waste underscores the need to develop sustainable biopolymers for food packaging. This study developed antimicrobial biocomposite films from cow hoof gelatin, microcrystalline cellulose powder, Myrothamnus flabellifolius (MRY) extracts green-synthesized zinc oxide nanoparticles (ZnO NPs) and ZnO NPs/β-cyclodextrin nanocomposites. The ZnO Nps and ZnO/β-CD nanocomposites were characterised using UV-Vis and FTIR spectroscopy. These materials were integrated into composite films, where the insoluble cellulose was incorporated as a dispersed phase via high-shear mixing to act as a reinforcing filler, with glycerol as a plasticizer. The films were evaluated for mechanical, swelling behaviour, water solubility, color, light transmittance and antimicrobial properties of key food pathogens. The findings show that ZnO/β-CD nanocomposites enhanced significantly physical, mechanical and antimicrobial properties of films. Among other performing films, the optimal formulation containing C: gelatin 11% w/v, cellulose 1.5% w/v, glycerol 23% v/v along 1.5% ZnO/β-CD and 5% MRY (C1.5zβ,5e) extract, demonstrated good antimicrobial activity with a mean inhibition zone of 26.54 ± 0.55 mm. Additionally, β-CD complexation improved nanoparticle dispersion and reduced film swelling. The incorporated cellulose contributed to a more compact film structure, improving mechanical integrity of the biocomposite films. Although higher concentrations of MRY extract and glycerol decreased mechanical strength, the optimal film maintained sufficient integrity for packaging applications. The ZnO/β-CD nanocomposite presents an effective strategy for developing antimicrobial packaging. Therefore, the C1.5zβ,5e film can be recommended for active meat packaging and for further evaluation in real food environment. Overall future studies should address issues of higher water solubility of biocomposite films associated with hydrophilic additives.