Recent advances in the development of intelligent packaging materials using black wolfberry (Lycium ruthenicum Murr.) anthocyanins

Plant anthocyanins-based food freshness indicators have gained increasing attention in intelligent packaging field, due to their nondestructive, real-time, convenient and consumer-friendly merits. Among abundant plant resources, black wolfberry ( Lycium ruthenicum Murr.) is rich in substantial acylated anthocyanins, particularly petunidin-3- O -( trans - p -coumaroyl)-rutinoside-5- O -glucoside. Moreover, black wolfberry anthocyanins exhibit remarkable pH-responsive color changeability, transitioning from red to colorless, purple, blue, and brown as pH increases. This unique pH-responsive property makes them good candidates for intelligent packaging applications. To date, various forms of intelligent packaging materials, including hydrogel films, aerogels, nanofiber films, and printing inks, have been prepared using black wolfberry anthocyanins. The physical and functional properties of intelligent packaging materials can be modulated by selecting proper polymeric backbones and anthocyanin content, adding reinforcing agents, and controlling the preparation and storage conditions. In this review, we comprehensively summarize: (1) the extraction, isolation and purification methods of black wolfberry anthocyanins, (2) their composition, stability and key functions for intelligent packaging use, (3) the preparation methods, physical and functional properties, and application potentials of black wolfberry anthocyanins-based intelligent packaging materials; and (4) the challenges in scaling up and commercializing these materials. This review can provide a guideline for the targeted use and rational design of black wolfberry anthocyanins in intelligent packaging.