Accurate Monitoring of Shrimp Freshness via Cornflower Anthocyanins-Loaded Bio-based Nanofiber Mats and Casted Films.

In the current study, novel pH-sensitive halochromic labels were fabricated by incorporating Centaurea arvensis anthocyanin (CAE) within PVA/Ҡ-carrageenan-based solvent casted films and electrospun nanofiber mats. The designed indicators were characterized and employed to detect the shrimp's freshness/spoilage state throughout the storage period at 4 °C. According to FE-SEM images, mats showed bead-free and continuous microstructures and CAE incorporation changed some of cylindrical fibers to ribbon-like shapes. Also, blending κ-carrageenan with PVA improved the integrity of films and formed finer fibers with lower diameters. DSC analysis approved more amorphous structures of nanofibers than films and new hydrogen bonding interactions by adding κ-carrageenan. The indicators demonstrated distinctive color shifts from heather violet to green in pH 2–12 buffer solutions. Nanofibers exhibited higher color stability, reversibility, and sensitivity than films. The CAE-loaded PVA and PVA/κ-carrageenan films showed visually-distinguishable color shifts from heather violet (fresh) to brown (better to eat) and greenish-brown/olive-yellow (spoiled) during shrimp storage. In addition, the color of CAE loaded PVA and PVA/κ-carrageenan nanofibers changed from light pink to white and mint-green/olive-green through shrimp spoilage. Trials on shrimp indicated the colorimetric responsiveness of the smart electrospun nanofibers strongly correlated with the pH, total volatile basic nitrogen (TVB-N), total psychrophiles count (TPC), and total viable count (TVC) changes in packaged shrimp. This research showed that electrospun nanofibers are promising candidates for use as highly sensitive and accurate pH labels in food intelligent packaging. [ABSTRACT FROM AUTHOR]