Kyushu scientists create smart film that changes colour when meat spoils

The Story in Brief

Researchers at Kyushu University have developed a smart packaging film that turns from purple-red to yellow-green when meat begins to spoil, offering a visual freshness indicator without opening the package. The hydrogel film uses anthocyanin from purple sweet potatoes embedded in a metal-organic framework, which protects the pigment while allowing it to react to alkaline gases from decomposing meat. The material also self-heals, recovering 99% of its strength after being cut, and is biodegradable. The study appears in the Chemical Engineering Journal.