Preparation and characterization of bioactive binary composite film based on gelatin–dextran incorporated with citronellal and α‐tocopherol

Abstract

Abstract Biodegradable active packaging films with antimicrobial and antioxidant functions have received much attention due to the food safety and plastic pollution issues. This study prepared and characterized a novel bioactive binary composite film based on gelatin (Ge) and dextran (Dx) incorporated with various concentrations (0%, 0.3%, 0.6%, 0.9%, 1.2%, w/w) of citronellal (Cit) and α‐tocopherol (Toc). The thickness, L*, b*, total color difference, water contact angle, opacity, and crystallinity of film significantly increased, whereas the film solubility, swelling degree, water vapor permeability, tensile strength, elongation at break, and a* of film significantly decreased with the increase of Cit and Toc concentrations. However, the addition of Cit and Toc had no significant effect on the film's moisture content and thermal stability. Fourier transforms infrared spectral pattern indicated that physical interactions (H‐bonding) between biopolymer matrix and active fillers were formed. Scanning electron microscope images showed that the film added with active fillers had a rough surface and a spongelike cross‐section structure compared to control film. Moreover, the release curves of Cit and Toc showed that the film in 95% ethanol solution had the longest release time. Furthermore, the film added with Cit and Toc effectively inhibited the growth of pathogenic and spoilage bacteria (Shewanella putrefaciens and Escherichia coli) and quenched the free radicals (2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid)). Overall, it can be inferred that the Ge–Dx‐based composite film incorporated with Cit and Toc is a potential antibacterial and antioxidant biodegradable material for food packaging applications to maintain food quality.

Keywords

• active packaging
• citronellal
• dextran
• gelatin
• α‐tocopherol