Enhancing Sustainability of Palm-Leaf Foodware by Secretion of Surface Wax Layer

Areca catechu palm leaf sheath has shown promise as a sustainable natural material for eco-friendly foodware. One of the principal factors controlling the life of palm-leaf foodware is diffusion of water through the sheath, which results in lowering of structural integrity of the plant material. We study diffusion of water through the sheath using mass gain measurements and in situ observations of water transport. We find that subjecting the sheath to a short-time thermal treatment at 120⁰C reduces the diffusion coefficient of water by 1/4 compared to that in the untreated sheath, along with a 4-fold increase in sheath-product life. This reduction of diffusion is shown to be a consequence of secretion of a thin natural hydrophobic wax layer onto the sheath surface from the bulk. By controlling the thermal treatment, a uniform wax surface layer can also be achieved. The results suggest opportunities for improving foodware product life and sustainability of these plant-based products