Monitoring of Persistent and Emergent Pollutants in black scabbard fish Aphanopus carbo by-products and protein hydrolysates

The Portuguese population consumes approximately 2.5 times more fish than the EU average. Black scabbardfish (Aphanopus carbo, BS) is a popular fish species, commercially available as whole/gutted or in portions/fillets. During processing, approximately 30–40% of by-products are generated (heads, bones, skins). These by-products are often discarded or undervalued, although they can be a valuable source of bioactive ingredients with many applications. The production of protein hydrolysates (PHs) is of great interest as they exhibit a variety of important bioactive and technological properties, making them potential ingredients for new functional foods and supplements. Their incorporation into food and animal feeds offers multiple benefits, yet these by-products can also carry environmental pollutants (EPs).

In this study, 40 EPs were analysed in BS by-products and their freeze-dried PHs. A single QuEChERS extraction followed by dispersive solid-phase extraction clean-up was employed, coupled with gas chromatography using either flame photometric detection or electron capture detection. This approach enabled the determination of organochlorine pesticides, polychlorinated biphenyls, brominated flame retardants, organophosphorus pesticides, organophosphate esters, and dioxins.

Trace amounts of EPs were detected in all by-products and PHs analysed. However, most concentrations remained below the EC’s maximum residue limits, except for DDE in the PH one-stage enzymatic hydrolysis with ProtanaPrime® (PH_P). These findings suggest that PHs from BS by-products can be safely incorporated into food products and animal feed (PH_P up to 30% due to DDE). Continued surveillance and regulatory action of EPs are crucial to promote a blue circular economy aligned with OneHealth principles.

This work received support and help from FCT/MCTES(LA/P/0008/2020-DOI10.54499/LA/P/0008/2020,UIDP/50006/2020-DOI10.54499/UIDP/50006/2020,UIDB/50006/2020-DOI10.54499/UIDB/50006/2020), through national funds. This work has been developed within the scope of the BlueBioeconomyInnovationPact (NºC644915664-00000026), financed by NextGenerationEU, under the incentive line “Agendas for Business Innovation” of the Recovery and Resilience Plan.