Green Food Packaging with Integrated Functions of High-Efficiency Radiation Cooling and Freshness Monitoring

Abstract

An optimal temperature environment is crucial for ensuring that the freshness of agricultural products is maintained during transportation. However, packaging materials often have a limited ability to dissipate heat and cannot accurately indicate the condition of the products, leading to significant losses in the logistics. Here, in order to achieve the fresh delivery of agricultural products, we constructed a ZnO-nanorods/cellulose membrane-starch membrane@blueberry anthocyanins (ZnO-NRs/CM-SM@BA) packaging material that has efficient heat dissipation to delay spoilage and the ability to accurately indicate the freshness of agricultural products via color changes. The ZnO-NRs/CM layer exhibited high visible reflectivity (94.4%) and infrared emissivity (98.8%) with the help of the rod-like structure of the ZnO-NRs, which contributed to a substantial reduction of heat input and a strong dissipation of heat accumulation. Compared with a PE film when in outdoor mode, the obtained membrane was able to realize passive cooling of 6.5 °C. Furthermore, the addition of anthocyanins caused Zn-NRs/CM-SM@BA to be sensitive to pH changes, showing different colors in the face of different pH environments. When applied to monitor the freshness of agricultural products, ZnO-NRs/CM-SM@BA showed a significant color change from celadon to pink with the decay of the agricultural products. The prepared ZnO-NRs/CM-SM@BA combines intelligent packaging materials with passive radiation cooling materials, thus making a superior contribution to reducing unnecessary losses in agricultural product logistics and expanding the single indicating role of intelligent packaging to the field of thermal management.

Advancing Sustainable Development: Broad Applications of Passive Radiative Cooling

“…Experimental results indicated that utilizing this film for packaging strawberries under direct sunlight can extend their storage time up to 9 days (shown in Figure 7c), demonstrating its potential as a superior solution for food preservation. In further advancements, Chen et al [120] developed a novel packaging material based on ZnO Nanorods/Cellulose Membrane-Starch Membrane@Bilberry Anthocyanins (ZnO-NRs/CM-SM@BA). This packaging material leverages the rod-like structure of ZnO nanorods, exhibiting a visible light reflectance of 94.4% and an IR emissivity of 98.8%, substantially reducing heat intake and enhancing the dissipation of thermal accumulation.…”

Construction of a Robust Radiative Cooling Emitter for Efficient Food Storage and Transportation

“…Until now, some research on integrating RC technology for packages has been reported. Chen et al proposed a smart packing material for the fresh delivery of agricultural products, which achieved high visible reflectivity and infrared emissivity of 94.4 and 98.8%, respectively, and realized cooling of 6.5 °C . Xu et al reported a nanocomposite hydrogel packaging with high solar reflectivity and infrared emissivity that can effectively prevent the anthocyanin and trypsin from degradation .…”