Smart packaging films based on starch/polyvinyl alcohol and Lycium ruthenicum anthocyanins-loaded nano-complexes: Functionality, stability and application

Smart packaging films were prepared by individually adding free Lycium ruthenicum anthocyanins and anthocyanins-loaded nanocomplexes into starch/polyvinyl alcohol (PVA) blend. The functionality, stability and practical application of the films containing free anthocyanins and anthocyanins-loaded nanocomplexes were compared. Results showed 68.4% of anthocyanins were encapsulated in nanocomplexes. Anthocyanins-loaded nanocomplexes had the average particle size of 242.1 nm, the zeta potential of +28.13 mV, the polydispersity index of 0.186, and the core-shell structure. The prepared starch/PVA film containing anthocyanins-loaded nanocomplexes (SP-AN film) had denser micro-structures, stronger intermolecular interactions, and higher water vapor blocking and mechanical properties than the film containing free anthocyanins (SP-FA film). However, SP-FA film presented higher light blocking and antioxidant properties than SP-AN film. Notably, SP-AN film showed higher stability than SP-FA film when the films were exposed to heat (35 °C) and light radiation for 30 days. SP-FA and SP-AN films were further used to package refrigerated largemouth bass (Micropterus salmoides) fillets. These two films effectively prolonged the shelf life of refrigerated bass fillets to 7 days and the films presented remarkable color changes when bass fillets spoiled. This work suggests SP-AN film was more suitable to be used as smart packaging material.