In vitro safety assessment, titanium migration analysis, and functional properties of chitosan-alginate bio-nanocomposite films with bay leaf extract and TiO₂ for sustainable chicken packaging.

Abstract

The development of sustainable bio-nanocomposite packaging materials has become essential to address environmental concerns while ensuring food safety. This study developed chitosan-alginate bio-nanocomposite films incorporating TiO₂ nanoparticles and bay leaf two-phased equilibrium condensate for chicken packaging. These natural polysaccharides were selected as biopolymer matrix due to their excellent film-forming properties, biodegradability, and antimicrobial characteristics. X-ray diffraction analysis confirmed both anatase (90%) and rutile (10%) phases of TiO₂ nanoparticles with sizes ranging from 21 to 34 nm. Dynamic mechanical analysis revealed that films containing 0.4% TiO₂ exhibited 30% increase in storage modulus while maintaining optimal viscoelastic properties. Bay leaf condensate incorporation significantly increased film hydrophobicity, as evidenced by higher water contact angles, while TiO₂ addition effectively reduced surface roughness. Under extreme degradation conditions (50 °C, 10 days), titanium migration remained below European regulatory specific migration limit, with maximum values of 1522 ± 96 ng kg-1 in 10% ethanol simulant. The strongest antibacterial activity was observed in films containing bay leaf condensate and 0.2% TiO₂, achieving total bacterial counts of 5.62 ± 0.33 and 3.58 ± 0.14 log CFU g-1 under refrigerated and frozen conditions, respectively. Safety assessment included simulated gastrointestinal digestion followed by intestinal absorption modelling using differentiated Caco-2 enterocyte-like monolayers and cytotoxicity evaluation in BJ fibroblasts and HepG2 hepatocytes. Film digestates were non-cytotoxic (IC₁₀) and did not impair mitochondrial membrane potential. 14-day exposure to digestates (100 μg mL-1) induced no genotoxic effects in BJ fibroblasts (1.75-3.77% vs control 3.11%) or HepG2 he