Cellulose nanofiber mediated natural dye based biodegradable bag with freshness indicator for packaging of meat and fish

This work reports the development of a biodegradable bag with freshness detection property for packaging of fish and meat. A nanocomposite film was prepared using cellulose nanofibers and cellulose acetate. Cellulose nanofibers were synthesized from cellulosic materials extracted from grass. Naturally occurring anthocyanin was introduced to activate the film for ammonia detection. Anthocyanin was extracted from the seeds of a dye bearing plant called Melastoma Malabathricum. Presence of cellulose nanofibers facilitates the absorption of anthocyanin on the film surface. The inherent property of colour changing ability with the change in pH, anthocyanin converts the film into a sensor for ammonia vapour. This colour change ability of the films was characterised using a colour measurement instrument. The film showed a tensile strength of ⁓29 MPa and thermal stability ⁓288 °C. Utilizing the thermoplastic nature of cellulose acetate, such films could be easily converted to a packaging bag by heat sealing.