Sustainable Active Packaging from On-Demand Degradable PLA/PBAT and Zn-Doped TiO2 Composites

Abstract

Shelf life extendable packaging and ethylene scavenger technologies for climacteric fruits and vegetables have garnered much attention in recent years. These products effectively enable food quality to be maintained, ensure food safety, and prolong food storage life, which are key to helping reduce food waste. Current technologies - both in terms of academic research and broader commercial application - imply the use of chemicals that are of low activity, of high toxicity, or difficult to handle. Therefore, in this work, we prepared Zn-doped TiO2 photocatalysts, containing 0.1 and 2.0 mol % of Zn dopant (Zn0.1%-TiO2 and Zn2%-TiO2), through a simple sol-gel method, which were then applied to be used as ethylene scavenger fillers in the preparation of on-demand degradable active packaging. TiO2 particles were also prepared under identical conditions for comparison. The active composite film containing Zn0.1%-TiO2 was shown to be a better active packaging than the one containing TiO2 and was able to extend the shelf life of bananas for up to 8 days. In addition, the incorporation of Zn-doped TiO2 particles did not significantly compromise either the mechanical properties of the polymer composite film or change its degradation behavior; it slightly improved the thermal stability. Moreover, the active composite film could be degraded on demand by immersing it into a 3 M KOH solution - leading to almost complete polymer film degradation after 4 h at room temperature. The developed active packaging model is a very promising candidate and could serve for future optimization as sustainable active food packaging.