Carrageenan–sodium alginate biodegradable films enriched with rosemary oil for active food packaging and shelf-life extension of apricot

This study aimed to develop and characterize biodegradable food packaging films composed of carrageenan and sodium alginate. To enhance the films, rosemary oil (RMO), extracted using ultrasound-assisted extraction with hexane as the solvent, was incorporated into the formulation. Five formulations were prepared: S0 (control), S1 (0.25 mL), S2 (0.50 mL), S3 (0.75 mL), and S4 (1.00 mL RMO). Film thickness increased from 0.083 ± 0.005 mm (S0) to 0.196 ± 0.029 mm (S4), while moisture content decreased from 15.34 ± 0.44% to 14.13 ± 0.95%. Water solubility was significantly reduced from 88.30 ± 0.30% in S0 to 72.60 ± 0.75% in S4, indicating improved water resistance. Tensile strength decreased from 8.27 ± 0.036 N/mm 2 (S0) to 2.22 ± 0.220 N/mm 2 (S3), followed by partial recovery in S4 (3.44 ± 0.040 N/mm 2 ). The films exhibited concentration-dependent antibacterial activity, with S4 showing the highest inhibition against Staphylococcus aureus (22 ± 1.00 mm) and Pseudomonas aeruginosa (26 ± 1.00 mm). Hemolytic activity ranged from 22.01% (S1) to 44.73% (S4), indicating increased erythrocyte membrane disruption at higher rosemary oil concentrations. Application of the optimized films on apricot fruits stored for 10 days effectively reduced weight loss (13.51 ± 0.01% in S4 vs. 19.80 ± 0.13% in uncoated fruits), preserved moisture (61.04% vs. 48.71%), and maintained firmness (28.42 ± 1.09 N vs. 58.11 ± 1.54 N) compared with the control. The Study demonstrates that rosemary oil-enriched Carrageenan–sodium alginate films exhibit promising physicochemical and antibacterial properties. They can serve as sustainable active packaging materials to extend the shelf life of fresh produce.