Effect of carboxylation cellulose nanocrystal and grape peel extracts on the physical, mechanical and antioxidant properties of konjac glucomannan films

Abstract

Active bionanocomposite films were prepared by incorporating konjac glucomannan (KGM) as a matrix, with carboxylation cellulose nanocrystal (C-CNC) as a reinforcement agent and grape peel extracts (GPE) as a natural antioxidation agent. The effects of C-CNC and/or GPE addition on the structural, morphological, barrier, thermal, mechanical and antioxidant properties of the bionanocomposite films were investigated. The rheological results of film forming solutions revealed that C-CNC and GPE were well dispersed in the KGM matrix. Scanning electron micrographs observed the addition of C-CNC had little effect on the microstructure, while more roughness and unevenness were observed on the film surface and cross-section with the C-CNC and GPE. Furthermore, the water vapor barrier property and transparency of the films improved by the addition of the C-CNC and GPE. Notably, the incorporating of C-CNC or GPE significantly alter the mechanical of the KGM/C-CNC/GPE bionanocomposite films. The highest tensile strength was achieved for the KGM/GPE bionanocomposite film with 10 wt% C-CNC, indicating C-CNC and GPE had synergistic effect on enhancing the TS of KGM film. Moreover, the KGM/C-CNC/GPE films exhibited strong antioxidant activity. These results suggested that KGM/C-CNC/GPE bionanocomposite films can be used as an active food packaging for increasing shelf life of packaged foods.