Self-healable and biodegradable konjac-glucomannan-blended sodium alginate films for food packaging

Abstract

The development of sustainable and functional alternatives to conventional plastic packaging is critical in addressing environmental concerns and food preservation challenges. Here, we develop self-healable biodegradable films based on sodium alginate and konjac glucomannan, plasticized with sorbitol, using a straightforward single-step casting method. Here, we develop self-healable biodegradable films based on sodium alginate and konjac glucomannan, plasticized with sorbitol, using a straightforward single-step casting method. Besides being investigated in terms of their water-triggered autonomous self-healing performance, these films have been applied on fresh fruit products, which clearly show their outstanding properties and high potential in real applications. The resulting films exhibit water-triggered intrinsic self-healing capability, achieving tensile strength recovery efficiencies of 95.76% and 73.65% for pure sodium alginate and konjac-glucomannan-blended sodium alginate composite films, respectively. Physicochemical and mechanical characterizations confirm that healing does not significantly alter film thickness, tensile strength, elongation at break, Young’s modulus, or water vapor transmission rate. Application trials on red grapes (Vitis vinifera L.) using brushing and wrapping techniques demonstrate the films' effectiveness in preserving weight, firmness, titratable acidity, vitamin C content, and visual appearance over a 20-day storage period under ambient conditions. These findings highlight the dual role of konjac-glucomannan-blended sodium alginate films as both biodegradable packaging and active self-repairing materials, offering a scalable, environmentally friendly solution for fresh produce preservation.