Novel Robust, Reusable, Microbial‐Resistant, and Compostable Protein‐Based Cooling Media

Abstract Novel environment‐friendly heat‐storage materials with efficient cooling capacity are in high demand by the food, pharmaceutical, and related industries and supply chains. Better control and prevention of cross‐contamination caused by meltwater from traditional ice have become critical to ensure the safety and quality of food and other commodities. Here is reported a microbial‐resistant, reusable, and compostable novel stationary cooling medium, “Jelly Ice Cubes” (JICs), based on gelatin–menadione sodium bisulfite (MSB) hydrogels (Gel/MSB‐JICs) with cooling efficiency comparable with traditional ice. For the first time, the photo‐crosslinking reactions induced by MSB are proposed and validated theoretically and experimentally. Photo‐tuning is used collectively with rapid‐freeze‐slow‐thaw treatment to construct robust hydrogel frameworks against the functional and structural damages caused by the phase transition of water during repeated uses. Exceptionally stable cooling efficiency and robust mechanical strength are observed across ten application cycles, with stable antimicrobial functions against bacteria, fungi, and yeast. At the end of the lifecycle of JICs, they can be composted or used as a soil treatment to promote plant growth. The novel JICs are competent as promising, safer, and more eco‐friendly substitutes for traditional ice and ice packs.