Enhancing the Mechanical, Barrier, and Biodegradability Properties of KGM/Agar/Pullulan Composite Films Through Controlled Deacetylation for Sustainable Packaging

Abstract

This study investigates the controlled deacetylation of konjac glucomannan (KGM) and its incorporation into agar (AGAR) and pullulan (PUL) to fabricate composite films (DKAP) for sustainable packaging applications. The effects of varying deacetylation degrees on the physicochemical and functional properties of KGM and the resulting films were systematically evaluated. FTIR analysis confirmed effective acetyl removal with an increase in deacetylation degree, which was accompanied by reduced viscosity. Moderate deacetylation improved intermolecular interactions, leading to enhanced mechanical strength, water vapor barrier properties, and hydrophobicity. The D 4 KAP film, with optimal deacetylation, exhibited the best overall performance, with a tensile strength of 85.47 ± 4.21 MPa and a water vapor permeability of 0.98 ± 0.06 × 10 −6  g·m −1 ·h −1 ·Pa −1 . Additionally, the D 4 KAP film showed reduced swelling and solubility compared to other films. Excessive deacetylation (above 35%) caused aggregation, structural defects, and reduced performance. All films remained biodegradable in natural soil, and fruit preservation tests (bananas and strawberries) showed that D 4 KAP effectively reduced water loss and preserved fruit quality, demonstrating its potential as an eco‐friendly packaging material. These results provide new insights into the optimization of biodegradable films for food packaging, highlighting the significance of controlled deacetylation in improving film performance and sustainability.