Micro- and nanoencapsulation of natural anthocyanins and their application in biodegradable intelligent packaging films: a review

Abstract Anthocyanins (ACNs) have attracted significant attention as potential natural pigments for biodegradable packaging films due to their pH-sensitive properties. However, incorporating ACNs into biodegradable packaging can be challenging due to their instability in environmental factors such as temperature and light. Micro- and nanoencapsulation offer advanced solutions to improve the stability, functionality, bioavailability, and controlled release of ACNs. This review paper provides an overview of recent advances in the micro- and nanoencapsulation of ACNs, including techniques, wall materials, and methods for their incorporation into biodegradable packaging materials. Micro- and nanoencapsulation techniques such as electrospinning, complexes/nanocomplexes, emulsions, ionic gelation, adsorption, and the combination of anti-solvent precipitation and layer-by-layer assembly have been employed with various biopolymers as wall materials, including carbohydrates, cellulose, gums, proteins, lipids, and nanoclays. Various film preparation methods, including solvent casting, electrospinning, and three-dimensional printing (3D printing), have been applied. Furthermore, the incorporation of encapsulated ACNs into intelligent packaging can successfully monitor food quality and freshness due to their pH-sensitive properties. This review also addresses the challenges of improving the stability of ACNs and film properties, as well as the scalability of production. The future perspectives have also been discussed.