Chitosan coating with Pickering emulsion of cellulose nanofibril/kaffir lime leaf essential oil for gourami fillets preservation

Gourami fillets ( Osphronemus goramy ) are susceptible to rapid deterioration during chilled storage. This study developed a chitosan-based edible coating containing a cellulose nanofibril (CNF)-stabilized Pickering emulsion of kaffir lime leaf essential oil (KEO) and evaluated its fish-preservation performance. A CNF concentration of 0.25% was selected as chitosan/CNF/KEO (ChiCK) stabilizer, and comparing with chitosan (Chi), chitosan/Tween 80/KEO (ChiTK). A ChiCK showed the highest zeta potential (57.00 ± 1.04 mV) and inhibition zones of 9.262 ± 0.639 mm, 10.306 ± 0.127 mm, 9.472 ± 0.824 mm, and 8.696 ± 0.260 mm against Escherichia coli , Pseudomonas aeruginosa , Bacillus cereus , and Staphylococcus aureus respectively. Its application on gourami fillet was able to suppress microbial growth with total plate count of 5.30 ± 0.05 log CFU g −1 , 1.12 log units lower than that of the uncoated fillets by day 2 storage and remined below the maximum limit of safe level (5.70 log CFU g −1 ), although the treatment did not reduce weight loss by day 3. The CNF-stabilized KEO coating therefore had potential for preserving the gourami fillets during chilled storage (5 °C–10 °C).