Sodium iron chlorophyllin-reinforced chitosan/gelatin films for fresh-cut vegetable packaging

Despite the abundance and potent UV-shielding capacity of chlorophyll, its application in food-packaging films remains unexplored. Here, we first demonstrate that FeCl₃-modified chlorophyll from goji leaves (FC) possesses robust antioxidant and antibacterial activities: IC₅₀ values for DPPH and ABTS radicals are 6.26 and 6.32 mg/mL, respectively, and 2.0 mg/mL FC generates antimicrobial inhibition zones of 30.8 mm (S. aureus) and 22.3 mm (E. coli). Rheological data show FC markedly reinforces the CS/Gel network, yielding composite films with markedly enhanced mechanical strength (tensile strength 5.31 ± 0.12 MPa, elongation at break 183.16 ± 0.56 %), water resistance (water absorption 52.51 %, water solubility 19.57 %), and oxygen barrier (oxygen permeance 178.53 ± 0.06 mL/ (m² d atm)), while blocking 98.4 % of UV and 40.0 % of visible light. Applied to fresh-cut chili peppers, the CS/Gel-FC film reduced microbial growth by 38.3 %, weight loss by 32.9 %, and slowed color changes—red (a*) and yellow (b*) indices increased 78.9 % and 91.3 % less than controls—thereby preserving safety and freshness over 15 days. This work advances understanding of chlorophyll–biopolymer interactions and offers a green strategy for UV-resistant, biodegradable packaging in the produce industry.