Improving the antioxidant ability of gelatin-chitosan film by incorporating an oil-in-water (O/W) Pickering emulsion emulsified by betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles

Active food packaging films with biological activities are a promising food technology, and antioxidant ability is one of the most important biological activities. In this study, an antioxidant active packaging film was prepared by directly blending gelatin, chitosan and a novel O/W Pickering emulsion and then drying. The emulsion was prepared from two antioxidant compounds, Mesona Chinensis essential oils (MCB-EO) and betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles (betanin-QAMSNPs), which provide this emulsion with high antioxidant activity. After adding the emulsion, the water content (26.63 %), water solubility (28.3 %), and water contact angle (86.2°) of the film are lower than those of the gelatin-chitosan film. The thickness and water vapour permeabilities of the betanin-Pickering emulsion film are 275.25 µm and 4.802 × 10⁻¹⁰ g·s⁻¹·m⁻¹·Pa⁻¹, respectively, which are higher than those of gelatin-chitosan films. Adding betanin-Pickering emulsions can decrease the roughness of the surface, which is observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The DPPH and ABTs⁺ free radical scavenging capacities of the betanin-Pickering emulsion films are 21.77 % and 91.87 %, respectively, which are higher than those of the gelatin-chitosan films (4.64 % and 61.15 %), indicating that adding the betanin-Pickering emulsion can enhance the antioxidant ability of the gelatin-chitosan films. The betanin-Pickering emulsion films can inhibit the oxidation of soybean oil. In conclusion, in this study, a novel food packaging film was successfully prepared and has potential application as an antioxidant food packaging material.