Fish Discards as Source of Health-Promoting Biopeptides

The vast diversity of marine organisms is a source of enormous potential for obtaining bioactive compounds for use in the food industry. In this context, discards, which are defined as the fraction of the fish catch that is not retained onboard but rejected to the sea due to commercial standards, fishing regulations, or them being nontarget species, are regarded as a waste of resources and an environmental problem. The new EU Common Fisheries Policy introduced a discard ban for pelagic species on January 1, 2015. The composition of discarded materials (1%-18% lipids and 15%-20% proteins) means that they are receiving increased attention for their use in biotechnological applications. The six species studied in this chapter, namely, the axillary seabream (. Pagellus acarne), small-spotted catshark (. Scyliorhinus canicula), sardine (. Sardina pilchardus), horse mackerel (. Trachurus mediterraneus), bogue (. Boops boops), and blue whiting (. Micromesistius poutassou), represent more than 85% of the total discards in the Alboran Sea. This chapter mainly focuses on upgrading the protein fraction of the aforementioned species into biopeptides. To this end, compacting and separation stages were designed to obtain the lipid and protein fractions. The influence of enzymatic hydrolysis on the antihypertensive, antioxidant, anticholesterolemic, and antimicrobial activities of the proteins was also analyzed. In addition, the bioavailability of the biopeptides was analyzed using simulated gastrointestinal digestion. Finally, the methods employed for the characterizing and identification of the active peptides are also described. These biopeptides can be employed in the formulation of functional food.