The Preparation and Characterization of Antioxidant Films Based on Hazelnut Shell-Based Vegetable Carbon Black/Chitosan/Gelatin and the Application on Soybean Oils

In this study, hazelnut shell-based vegetable carbon black (HCB) was synthesized from renewable agricultural waste and incorporated into chitosan (CS) and gelatin (GEL) matrices to fabricate active packaging films. The structure of HCB was characterized, and the structure, physicochemical properties, antibacterial activity, ultraviolet resistance, and functional performance of CS-GEL-HCB films with varying HCB contents (0, 1, 5, and 9 wt% based on GEL) were systematically investigated. The FT-IR results revealed that intermolecular hydrogen bonds were formed between HCB and CS and GEL. The results showed that the tensile strength of CS-GEL film (15.83 ± 0.40~32.06 ± 0.61 MPa), as well as its water vapor and oxygen barrier properties (0.55 ± 0.03~0.15 ± 0.02 g/d·m²), and UV-visible light barrier properties were significantly improved (<i>p</i> < 0.05) after the addition of HCB, while the water permeability, moisture content, and water solubility of CS-GEL film were effectively reduced (24.84 ± 0.45~20.10 ± 0.45%). More importantly, the CS-GEL-HCB film exhibited enhanced ultraviolet barrier properties, which helped delay the oxidation and deterioration of the oil sample during the accelerated light oxidation test. These results suggest that the CS-GEL-HCB film could serve as an effective food packaging material to improve the oxidation stability of soybean oil in the food industry, showing great potential in maintaining food quality and extending shelf life.