Synergistic improvement of mechanical and barrier properties of paper using a hemicellulose-based composite coating for high humidity kiwifruit preservation

The high humidity sensitivity of conventional packaging materials severely limits their efficacy in preserving climacteric fruits like kiwifruit, especially at humid conditions. To address this, a multifunctional composite coating was engineered by leveraging interfacial interactions between biopolymers and nanofillers, to facilitate a paper packaging material with exceptional barrier performance. The design synergistically combines the branched nature of hemicellulose (HC), the mechanical reinforcement of cellulose nanofibrils (CNF), the hydrophobicity of alkyl ketene dimer (AKD), the nano-barrier properties of montmorillonite (MMT), and the film-forming property of polyvinyl alcohol (PVA). This formulation resulted in a stable, thixotropic colloidal suspension ideal for uniform deposition onto lightweight paper. Microscopic and spectroscopic analyses confirmed the formation of a compact, continuous coating layer, stabilized by robust hydrogen-bonding networks and the β-keto ester bonds from AKD. The HC/PVA/CNF/MMT/AKD-coated paper exhibited enhanced tensile strength (38.94 MPa) and exceptional humidity-resistant properties (reflected by the ultra-low water vapor transmission rate of 1.10 g/(m 2 ·d), and Cobb value of 0.24 g/m²) and superior oxygen barrier performance (7.9 cm³/(m²·d)) that remained effective across a wide relative humidity range (13–95%). When deployed for kiwifruit preservation, the package effectively modulated the microclimate of the fruit, and markedly inhibited key spoilage-related enzymes, reduced firmness loss by over 50%, and curtailed browning by a 5 fold reduction. Consequently, the kiwifruit shelf life was effectively extended by 30% even at 95% RH and ambient temperature. This work underscores rational design of multi-component coatings for sustainable, humidity-resilient packaging with significant potential for preserving perishable produce. • Novel HC/PVA/CNF/MMT/AKD coated paper developed for kiwifruit packaging. • Coating markedly enhances paper strength, gas barrier & water resistance. • Kiwifruit shelf-life in the coated paper packaging was extended. • Key ripening & browning enzymes (LOX, PPO, PAL) in kiwifruit were suppressed. • Coating morphology and synergistic interactions contributed to enhanced performance.