In the current study, cellulose (C) was extracted from the aquatic weed, giant salvinia (Salvinia molesta) and converted into cellulose nanocrystals (CNCs) for utilizing as a reinforcing agent in biodegradable films for fish packaging applications. SEM and TEM micrographs confirmed the successful conversion of bulk cellulose into a crystalline (CNC) structure. FTIR spectra verified the removal of lignin and hemicellulose without altering the cellulose backbone. XRD analysis confirmed the cellulose I crystalline structure, showing an increase in crystallinity index from cellulose (59.2%) to CNC (69.4%), which indicates effective removal of amorphous regions. Particle size analysis revealed nanoscale dimensions for CNC (55 nm), and the zeta potential value of −53.9 mV indicated excellent colloidal stability. Further, a carrageenan-based active biodegradable film was developed by adding CNC at 5 % (w/w) by solvent casting. Pomelo peel (Citrus maxima) extract (PPE) was added at 5 % to the film-forming solution as an active agent. There was a significant (p≤0.05) increase in the tensile strength of the native carrageenan film upon CNC incorporation, and the antioxidant activity was improved by the addition of PPE into carrageenan films. A storage trial was conducted to evaluate the efficiency of the developed active biodegradable film on the shelf life of chilled stored (4 ± 2 °C) skipjack tuna (Katsuwonus pelamis). The results showed that the shelf life of tuna was extended from 8 days in the control, packed in synthetic plastic pouches, to 16 days when packaged with carrageenan + CNC + PPE.
Key words: Active packaging, Skipjack tuna, Carrageenan film, Salvinia molesta