Chitosan-Based Active Packaging with ZnO Nanoparticles and Green Tea Extract for Shelf-Life Extension of Chicken Loaf

Abstract

Chitosan-based biodegradable packaging films have gained considerable attention in food preservation because of their film-forming ability, antimicrobial activity and eco-friendly nature. The incorporation of zinc oxide (ZnO) nanoparticles and natural antioxidants, such as green tea extract (GTE), into chitosan films may further improve their functional properties and extend the shelf life of meat products. Therefore, the present study was conducted to evaluate the effect of chitosan-based packaging films incorporated with ZnO nanoparticles and/or GTE on the quality and shelf life of chicken loaf stored at room temperature (25°C). Four film formulations were prepared: chitosan alone (F1), chitosan with ZnO nanoparticles (F2), chitosan with GTE (F3), and chitosan with both ZnO nanoparticles and GTE (F4). Commercial LDPE film and unpackaged samples served as positive and negative controls, respectively. Chicken loaf samples were evaluated for physicochemical, microbiological, sensory and proximate composition parameters during storage. The results revealed significantly lower (p<0.01) pH and TBARS values in F2, F3 and, particularly, F4, indicating reduced microbial growth and lipid oxidation. The F4 treatment exhibited superior colour stability, with minimal changes in L*, a* and b* values during storage. Standard plate counts were significantly lower in F2 and F4 due to the synergistic antimicrobial effects of chitosan and ZnO nanoparticles, while coliforms, yeast and moulds, Staphylococcus aureus, and Salmonella were not detected. Sensory scores for appearance, flavour, juiciness and overall acceptability were highest in F4 throughout storage. The study demonstrated that chitosan films containing ZnO nanoparticles and GTE effectively enhanced the quality and shelf life of chicken loaf under ambient storage conditions.