Ambient-densified and polymer-free transparent wood film for smart food packaging window

Kailong Zhang; Isaac Sutton; Micholas Dean Smith; David P Harper; Siqun Wang; Tao Wu; Mi Li

doi:10.1016/j.isci.2023.108455

Ambient-densified and polymer-free transparent wood film for smart food packaging window

iScience. 2023 Nov 15;26(12):108455. doi: 10.1016/j.isci.2023.108455. eCollection 2023 Dec 15.

Authors

Kailong Zhang¹, Isaac Sutton², Micholas Dean Smith³, David P Harper¹, Siqun Wang¹, Tao Wu⁴, Mi Li¹

Affiliations

¹ Center for Renewable Carbon, School of Natural Resources, University of Tennessee, Knoxville, TN 37996, USA.
² Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA.
³ Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
⁴ Department of Food Science, University of Tennessee, Knoxville, TN 37996, USA.

Abstract

Wood, with its inherent hierarchical structure, presents opportunities for creating eco-friendly and cost-effective alternatives to petroleum-based plastics. We introduced a top-down and polymer-free method for engineering natural balsa wood into transparent wood film, demonstrating its potential use in food packaging windows. The wood was delignified and then proceeded with 2,2,6,6-tetramethyl-1-piperidinyloxy oxidation to soften the wood structure and introduce carboxyl groups. A robust and transparent wood film was produced by drying the wood under ambient condition without the need for additional polymers or mechanical force. Curcumin was also integrated into the wood using vacuum impregnation. The functionalized wood film with curcumin (WFC) exhibited a distinguishable redness shift in alkaline conditions. We then applied the WFC as an intelligent food packaging window to sense the freshness of shrimp based on the pH-responsive color change. This study provides a simple and scalable approach for developing sustainable and smart food packaging using wood.

Keywords: Biomaterials; Biotechnology; biomass; materials chemistry; materials science.