Production of chitosan-fish oil-green tea extract-based coating for Atlantic bonito (Sarda sarda) fillets preservation

Atlantic bonito ( Sarda sarda ) is a fish from Atlantic Ocean well-known for its pleasant taste and high nutritional value. However, it is susceptible to lipid and protein oxidation and spoilage. Sustainable bio-based edible coatings are increasingly a viable option for freshness preservation and to extend the shelf life of highly perishable food products. In this context, a coating formulation composed by chitosan (CH), fish oil (FO) and green tea extract (GTE) was developed for application on Atlantic bonito fillets’ surface to preserve their quality. An optimized coating formulation containing 1.25% CH, 0.30% FO, and 2% GTE based on an experimental design was selected, due to its barrier properties. Atlantic bonito fillets’ shelf-life analysis showed that the CH-GTE-FO coating reduced microbial count ( Enterobacteriaceae , total viable count (TVC) and psychrotrophic bacteria) over a six-day period. Furthermore, CH-GTE-FO minimized fillets’ lipid and protein oxidation, as well as color changes compared to the control sample. Notably, the fillets’ original textural parameters (hardness, adhesiveness and springiness) were preserved during storage due to the application of the optimized coating. Based on the shelf-life evaluation, the developed CH-GTE-FO coating proved to be effective in maintaining the quality properties of Atlantic bonito fillets, which could potentially extend its shelf life for, at least, six days. • CH-GTE-FO coating extends Atlantic bonito fillets' shelf life by 6 days. • Coating reduces microbial count (Enterobacteriaceae, TVC, psychrotrophs). • CH-GTE-FO prevents lipid and protein oxidation in Atlantic bonito fillets. • Fillet texture and color properties were preserved with coating application. • Optimized CH-GTE-FO coating formulation boosts quality and freshness retention.