Pectin-based film activated with carboxylated cellulose nanocrystals-stabilized oregano essential oil Pickering emulsion

Abstract

The high brittleness, susceptibility to moisture absorption and low biological activity of pectin films limit their development. To address these limitations, carboxylated cellulose nanocrystals-stabilized oregano essential oil Pickering emulsion (COPE) was prepared to activate pectin films. COPE has good compatibility, and it can be uniformly dispersed in pectin matrix, which promotes the stable formation of composite films characterized by tight entanglement and hydrogen bonding between COPE and pectin molecules. Compared with pure pectin film, pectin-COPE composite film shows higher tensile strength (16.03 MPa), elongation at break (25.27%), water contact angle (88.02°) and lower water vapor permeability (1.40 × 10−10 g/m·s·Pa). Importantly, COPE endows pectin film with unique anti-ultraviolet (composite film almost completely blocks light in the UVC (275-200 nm) and UVB (320-275 nm) regions, as well as most light in the UVA (400-320 nm) region), antioxidation (DPPH radical scavenging capacity and T-AOC were maximized by 4.53% and 2.72%, respectively) and antibacterial properties (a clear ring of inhibition appears around the composite film), allowing it to significantly extend the shelf life and maintain the quality of cherries when used for packaging. In conclusion, COPE offers novel strategies to enhance the bioactive, mechanical and hydrophobic properties of pectin-based films, and the pectin-based composite films activated by COPE can provide more opportunities for food preservation/packaging as potential petrochemical plastic substitutes.