Gelatin/calcium-caseinate films loaded with petitgrain essential oil for sustainable food packaging

This research focuses on the development and assessment of films composed of gelatin (GE) and calcium caseinate (CC), loaded with varying concentrations of petitgrain essential oil (PEO). A comprehensive assessment of the resulting films was conducted with a focus on the antioxidant, antibacterial, and physicochemical attributes. GCMS analysis identified the primary constituents of PEO, including linalyl acetate, linalool, alpha-pinene, alpha-terpineol, limonene, beta-myrcene, geranyl acetate, and neryl acetate. The antioxidant capacity of GE-CC films increased significantly with increasing PEO concentration, as evidenced by DPPH and ABTS assays. Simultaneously, increased PEO concentration led to increased thickness, water vapour permeability (WVP), elongation at break (EAB), and water solubility (WS) in the active films while reducing moisture content (MC) and tensile strength (TS). In terms of optical characteristics, the transparency of the films decreased, while the b* (yellowness) and Delta E (total colour variation) values increased upon oil incorporation. The presence of intermolecular interactions between the polymers and the oil was confirmed through FTIR and morphological characteristics studied by SEM. The addition of PEO to the films resulted in improved thermal resistance against degradation, as observed in the thermo-gravimetric analysis (TGA). Moreover, these active films showed potent antimicrobial activity against C. albicans and P. aeruginosa. In summary, this study underscores the suitability of GE-CC films containing PEO for food packaging purposes, highlighting their functional characteristics and environmentally friendly nature. Visual analysis of gelatin and calcium caseinate blank and composite films loaded with and without varying concentrations of petitgrain essential oil. Film samples loaded with and without oil exhibited homogeneous and even structures without any irregularities, demonstrating the good film-forming properties of the biopolymers as well as their compatibility with other components. image