Active packaging application of walnut kernels using ethyl cellulose-based antioxidant electrospun films containing carbon dots.

Sustainable active food packaging films have recently emerged as a critical focus in prolonging food's shelf life. Herein, the study focuses on the biopolymers ethyl cellulose (EC) and polyethylene oxide (PEO) for fabricating fibrous films through a simple electrospinning technique. The FE-SEM analysis showed the uniform morphology of the EC/PEO films with fiber diameters ranging from 0.58 μm to 1.81 μm by varying the amount of PEO in EC during the electrospinning process. Biomass-based sustainable carbon dots (CDs) were made from banana stems and were encapsulated into fibrous films through blend electrospinning as active agents. Incorporating CDs in the EC/PEO fibrous films increased water absorption, water vapor permeability, mechanical and thermal properties. The fibrous films exhibited excellent hydrophobicity (∼124 to 152°) and a low water solubility of 2.3 %. The developed active films demonstrated good antioxidant activity and could scavenge ∼40 % and ∼90 % of the DPPH and ABTS oxidative radicals, respectively. Further, the fibrous active films were used for packaging walnut kernels and substantially reduced their lipid oxidation by ∼33 % when stored at 40 °C for 6 weeks, as analyzed by the TBARS assay. The current study unveils a new avenue for the development of sustainable electrospun fibrous films to enhance the oxidative stability of food items like walnuts.