Engineering a high-performance, sustainable food packaging film: Zinc-doped carbon dots reinforced konjac glucomannan nanocomposite

Abstract

Developing bio-based food packaging films with excellent mechanical, preservation, and degradation properties is an urgent need in the field of food packaging. This study proposed to prepare a multifunctional food packaging film by incorporating zinc-doped carbon dots (Zn-CDs), quaternized chitosan (QCS), and tannic acid (TA) into konjac glucomannan (KGM) to address the mentioned challenge. KGM-QCS-TA-ZnCDs film (KQTZF) presented excellent mechanical properties with the tensile strength of 69.73 MPa, elongation at break of 15.88%, and tensile modulus of 19.79 GPa, which can be achieved through better interfacial bonding caused by hydrogen bonding and coordination bonding. The preservation experiment of plums showed a freshness preservation period of 9 days indicating excellent preservation performance, which can be attributed to the fact that good sterilization property bactericidal rate of 99%, water barrier property of 37 g·m/(m²·h·Pa), oxygen molecule permeability of 12.29 g·m/(m²·h·Pa), and free radical scavenging rate of 90% were endowed to KQTZF by the synergistic effect of Zn-CDs, QCS, and TA. Furthermore, the synergistic effect of Zn-CDs, QCS, and TA also accelerated the degradation rate of KQTZF in water, PBS, and soil, demonstrating good environmental friendliness and sustainability. The simultaneous improvement of mechanical properties, biodegradability, and preservation performance of food packaging films in this study provides new ideas for the development of multifunctional fruit preservation packaging materials.