Smart chitosan/κ-carrageenan biopolymer film enriched with grape peel anthocyanin/rutin nanoparticles for real-time beef and chicken meat freshness monitoring.

The demand for sustainable, halochromic packaging to monitor food freshness and extend shelf life remains unmet, highlighting the need for eco-friendly films with multifunctional properties. This study addresses this issue by developing smart/active nanocomposite films using chitosan (CS)/κ-carrageenan (KC) matrices infused with rutin nanoparticles (RUT NPs) and grape peel anthocyanins (GPAs) through a casting process. Dynamic light scattering revealed RUT NPs with an average size of 167.8 nm, a zeta potential of 3.04 mV, and a PDI of 0.506. Pure CS films (T1) exhibited high transparency (84.91), while CS/0.3 %KC/0.3 %RUT NPs/3 %GPA films (T7) showed reduced transparency (34.38) due to light absorption by flavonoids. GPAs imparted a violet hue, decreasing the b value (blue/yellow) from 25.75 (T1) to -5.35 (T7) and the a value (red/green) from -5.61 to 1.07. Moisture content ranged from 4.56 % (T7) to 5.76 % (CS/0.3 %KC). Water vapor permeability (WVP) decreased from 3.51 × 10-9 g·m/m2·s·Pa (T1) to 0.79 × 10-9 g·m/m2·s·Pa (CS/0.3 %KC/0.3 %RUT NPs/1 %GPA), indicating slower water diffusion. Tensile strength (TS) increased from 16.18 MPa (T1) to 23.86 MPa (CS/0.3 %KC/0.3 %RUT NPs), while GPAs improved elongation at break (EAB) to 29.22 % in T7 films. Antioxidant activity increased from 13.45 % (CS/0.3 % KC film) to 61.23 % (T7), with antimicrobial effects against E. coli (13.06 mm) and S. aureus (15.03 mm). The films displayed pH-responsive color shifts (reddish to violet to yellow), validated in a meat model, enabling real-time freshness monitoring. The study evaluated the T7 film as a food packaging material against control over 11 days. Chemical stability tests showed T7 maintains lower peroxide value (PV, 4.08 meq/kg vs. 5.73 meq/kg), pH value (pH, 6.12 vs. 7.72), and total volatile basic nitrogen (TVB-N, 13.9 mg/100 g vs. 24.5 mg/100 g), indicating reduced lipid oxidation and protein degradation. Microbiological analysis revealed T7 limits total viable count (TVC, 6.81 log CFU/g vs. 7.95 log CFU/g) and psychrotrophic bacterial count (PBC, 8.07 log CFU/g vs. 9.07 log CFU/g), demonstrating effective microbial inhibition. These findings indicate the T7 film's potential to enhance food preservation and shelf-life. These multifunctional films enhance meat safety, quality, shelf life, and sustainability, responding to the demand for eco-friendly packaging applications.