Pectin–cellulose nanofiber composites: Biodegradable materials for modified atmosphere packaging

Abstract

Pectin blended with cellulose nanofiber (CNF) sourced from wood pulp has excellent potential for modified atmosphere packaging (MAP), as demonstrated with refrigerated or sliced fruits enclosed in parchment coated with pectin–CNF composites. Addition of sodium borate (NaB) augments the antioxidant capacity of the composite, most likely through the generation of unsaturated pectic acid units. Packaging materials coated with pectin–CNF–NaB composites demonstrate better humidity regulation in refrigerated spaces over a 3-week period relative to uncoated controls (50% less variation), with improved preservation of strawberries as well as a reduction in the oxidative browning of sliced apples. Pectin–CNF films are both biorenewable and biodegradable as confirmed by their extensive decomposition in soil over several weeks, establishing their potential as a sustainable MAP material. Lastly, self-standing films are mechanically robust at 80% RH with tensile strength and toughness as high as 150 MPa and 8.5 MJ/m² respectively. These values are on par with other bioplastic composites and support the practical utility of pectin–CNF composites in functional packaging applications.