Edible composite films based on chitosan/guar gum with ZnO NPs and roselle calyx extract for active food packaging

The present study aimed to prepare and characterize edible composite films. The edible composite films were made from a mixture of guar gum/chitosan with the loading of zinc oxide nanoparticles (ZnONPs) and roselle calyx extract (RCEx). The incorporation of RCEx and ZnONPs improved the antioxidant and mechanical properties of films. Based on yield of bioactive compounds obtained by the UAE method was used for the development of ZnONPs and the edible composite film. The Cross-section microstructure of the films showed that the films were dense and compact. Although the incorporation of RCEx decreased the transparency of the films, it enhanced the UV–Vis light barrier properties. The tensile strength, elongation at break, and solubility of CS/GG film, CS/GG/RCEx and, CS/GG/RCEx/ZnONPs film was found to be (35.74 MPa, 54.24 MPa and, 69.42 MPa), (15.56%, 12.27% and, 9.69%), and (67.23%, 59.41%, and 61.35%) respectively. Water vapor permeability (WVP) of the films was decreased from 4.68 to 4.06 (g /m2.day.kPa) after the addition of zinc oxide nanoparticles into the films, respectively. RCEx and ZnONPs incorporated films showed the higher antioxidant activity than control film, 11.52%, 42.55% and, 68.15% respectively. This study showed edible composite films incorporated ZnONPs and RCEx have promising potential for applications in active food packaging in the future.