Polyphenol-loaded bacterial cellulose nanofiber as a green indicator for fish spoilage

Seafood products as a source of vitamins, minerals, and polyunsaturated fatty acids represent an important component of the human diet. However, they are susceptible to spoilage even under appropriate storage conditions, making it indispensable to develop freshness indicators. In this study, we introduce a green user-friendly pH indicator film for the naked-eye monitoring of fish spoilage. The pH indicator was prepared by successful loading of a mixture of anthocyanin and curcumin on bacterial cellulose (BC) nanofiber substrate. BC nanofiber with the advantages of biocompatibility, biodegradability, high purity, and superior mechanical strength was promising for generating pH-sensing arrays. The Fourier transform infrared (FT-IR) analysis proved the incorporation of anthocyanin and curcumin into the BC skeleton. Besides, the scanning electron microscopy (SEM) results clarified the morphology of the modified film by anthocyanin and curcumin. The pH indicator film was still stable after preserving for 60 days at different temperatures. The curcumin-anthocyanin loaded nanofiber indicated a distinct color change after spoilage by its exposure to fish meat in a transparent plastic package. Hence, the modified film by the anthocyanin-curcumin mixture is potent for the naked-eye monitoring of meat spoilage.