Development of added-value culinary ingredients from fish waste: Fish bones and fish scales

Abstract

Around 10% of the global fish catch (>90 million tonnes) is currently discarded, while by-products in fisheries account for up to 70% of the whole fish weight. From these, fish bones and scales represent 14–20% of by-products, which are also discarded. Therefore, there is an unmet need for valorising these by-products by transforming them into functional and nutritious ingredients. Towards this objective, we report herein different culinary processes to extract gelatine from fish scales, as well as fish flours from bones and scales, as innovative methods for waste valorisation in the food services industry. On the one hand, gelatine was extracted from demineralised and non-demineralised scales and their respective gelling and melting properties were analysed and compared in culinary elaborations. Both gelatines showed a lower melting point (23 °C) than pork gelatine (29 °C, used as control), which provided these gelatines with a smooth and creamy texture in mouth. On the other hand, financiers made of fish bone and fish scales flour were compared with those made with regular wheat-flour, resulting in no significant differences regarding their adhesiveness and springiness. These results showcase the potential of upcycling fish by-products into protein-rich value-added ingredients in the food services industry.