Effects of chitosan and carotenoids-based coating on the shelf-life of fresh sardine fillets

Background: Food packaging is currently facing several challenges and edible pack-aging is a promising option to extend the shelf-life of food and reduce food/packaging waste. In the framework of the “ONFoods-Research and innovation network on food and nutrition Sustainability, Safety and Security-Working ONFoods” project, this study aimed to develop a carotenoids-rich extract from red shrimp shells for enriching chitosan-based edible coating. The effectiveness of this coating with and without carotenoids extract in maintaining the quality and stability of fresh sardine fillets during shelf-life was evaluated to promote the principles of circular economy and waste valorization in seafood sector. Methods: Fresh sardine fillets were coated with two different edible coatings. One based on chitosan (1%), while the other on a combination of chitosan and carotenoids ex-tract (2.5%), a natural antioxidant ingredient obtained by an ethanol extraction process from red shrimp shells. The control sample (without edible coating) and the two coated ones were packed in a high barrier package under atmospheric conditions and stored at 4 °C for 13 days. Throughout the storage period, the sardine samples were analyzed for pH, aw, color, texture, lipid oxidation and microbial growth. Results: The shrimp shell extract showed a high concentration of carotenoids and high antioxidant activity. The chitosan-based coating, with or without carotenoids, was able to extend the shelf-life of sardine fillets by maintaining all quality parameters during storage. In particular, both coated samples showed lower lipid oxidation compared to the control; the sample with the carotenoids-enriched coating showed the lowest microbial load. Conclusions: This study highlights the potential of using chitosan coatings, alone or in combination with carotenoids from red shrimp shells, as an effective strategy to pre serve the freshness and quality of fish fillets and to contribute to the development of value-added seafood products with a long shelf-life.