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 proper-ties 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 en-hanced 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.