Functionalized cellulose nanocrystals reinforced polysaccharide matrix for the preparation of active packaging for perishable fruits preservation.

Polysaccharide-based films have received increasing attention as promising candidates for petrochemical plastics. However, they are highly brittle, poorly hydrophobic and without antibacterial activity, while current films used to address these issues often struggle to manage the balance between these properties. To achieve a balance of several performance indices of the films, functionalized dialdehyde cellulose nanocrystals (DCNCs) were prepared to activate pectin-based films. Structural characterization including dynamic light scattering techniques (DLS), scanning electron microscope (SEM), atomic force microscope (AFM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectrometer and x-ray diffraction (XRD) demonstrated that DCNCs were homogeneously dispersed in the pectin polysaccharide matrix and tightly cross-linked through hydrogen bonding interactions, which promoted the stable formation of high-performance composite films. Compared to pure pectin film, the composite film has better tensile strength (23.09 MPa), water contact angle (WCA, 91.23°), water vapor permeability (WVP, 1.02 × 10 g/cm·s·Pa), and exhibit excellent UV-resistance, DPPH radical scavenging capacity (27.04 %) and antibacterial activity that significantly extended the shelf life of strawberries (5 d). Furthermore, DCNCs can be used to enhance the mechanical strength (4.15-23.46 MPa), WVP (1.55-5.21 × 10 g/cm·s·Pa) and WCA (59.46°-61.03°) of various polysaccharide-based films, which validates their universality. This work effectively improves and balances the several properties of polysaccharide-based films, creating more opportunities for the wide application of polysaccharide-based films, such as food preservation packaging.