Development and Characterization of Chitosan-Based Films Enriched with Callistemon citrinus Extract for Food Packaging of Cheddar Cheese

This study investigated the effect of Callistemon citrinus flower extract (C.E.) on the structural and functional properties of chitosan-based bioplastics for food packaging applications. Increasing C.E. concentration produced changes in colour and opacity, with reduced L values and higher a values at 5% C.E., resulting in a reddish appearance. Film opacity increased from 2.49% ± 0.10 for control to 13.60% ± 0.72 for film with 5% C.E., reducing transparency. The addition of 5% C.E. improved oxygen barrier properties, reducing O2 permeability compared to the control that was similar to Low-density polyethylene (LDPE). A qualitative antimicrobial screening showed that 5% C.E. effectively inhibited S. aureus (16 mm) and L. monocytogenes (12 mm), while no inhibition was detected against E. coli. Cheddar cheese packaged in films with C.E. exhibited higher weight loss (11.63% at 28 days) than LDPE (2.90%), whereas moisture retention remained moderate (76.62% for the film with 5% C.E.). Oxidative stability improved with lower lipid oxidation (K232 = 2.90 at 28 days) in cheese wrapped in C.E. films. Consumer evaluation indicated a positive perception, with 73% of participants willing to purchase products in C.E.-packaged films. Overall, C.E. enhanced antioxidant and antibacterial benefits, but further optimization may be required to improve moisture retention.