Fish by-catches, along with other fish side-streams, were previously used as raw material for the production of fishmeal and fish oil but appropriate handling allows their use in more valuable options. The aim of this research was to valorize undersized hake (Merluccius merluccius) as a model of using fish by-catch from the Bay of Biscay to produce protein hydrolysates with bioactivities. Six enzymes, with different proteolytic activities (endo- or exoproteases) and specificities, were tested to produce protein hydrolysates. Products obtained with an endoprotease of serine resulted in the most promising results in terms of protein extraction yield (68%), with an average molecular weight of 2.5 kDa, and bioactivity yield (antioxidant activity = 88.5 mg TE antioxidant capacity/g fish protein; antihypertensive activity = 47% inhibition at 1 mg/mL). Then, process conditions for the use of this enzyme to produce bioactive products were optimized using Box–Behnken design. The most favorable process conditions (time = 2 h, solids = 50% and enzyme/substrate = 2% with respect to protein) were scaled up (from 0.5 L to 150 L reactor) to confirm laboratory scale and model forecasts. The results obtained in the pilot-scale testing matched the outcomes predicted by the model, confirming the technical viability of the proposed process.

Brewer’s spent yeast (BSY) is produced by the beer industry and has high nutritional value and great potential for producing high-value molecules, such as peptides, for nutraceutical, food and feed applications. In the present research, Flavourzyme^® and Protamex^® enzymes were selected for protein hydrolysis based on previous studies. The optimum conditions for the enzymatic hydrolysis were defined by response surface methodology (RSM) by the Box–Behnken design composed of four variables: temperature, pH, enzyme dosage and time. Protein content, hydrolysis degree and the anti-microbial and antioxidant bioactivities of obtained hydrolysates were quantified. Obtained results show that time, enzyme dosage and pH had the highest effect on protein extraction yield (PEY), degree of hydrolysis (DH) and antioxidant activity. Response variables ranged from 13.7 to 29.7% for PEY, from 6.3 to 35.7% for DH and from 0.65 to 1.65 g for Trolox equivalent antioxidant capacity. Antimicrobial activity, measured as minimum inhibitory concentration, against Aeromonas salmonicida, Bacillus cereus, Bacillus subtilis and Salmonella enterica, ranged from 6.25 to 50 mg/mL. Antioxidant and antimicrobial activity showed the potential use of BSY hydrolysates as an ingredient for functional foods.

Growing demand in the fisheries sector has resulted in a high generation of side-streams that are mainly treated as waste despite their potential value in terms of protein, fatty acids, and minerals. The WaSeaBi project, funded by the EU under the Horizon 2020 BBI JU initiative, seeks to address this problem by promoting the sustainable and economically viable utilisation of these side-streams, thus contributing to improved food security and environmental conservation. The project focuses on the development of innovative technologies and methodologies for the efficient valorisation of seafood side-streams into marketable products such as protein-based food ingredients, bioactive peptides, and mineral supplements. The WaSeaBi project started with a comprehensive analysis to identify the bottlenecks hindering the efficient utilisation of side-streams. To this end, a comprehensive study of the European seafood industry was conducted to understand the existing challenges. The main obstacles identified were technological deficiencies, lack of space and personnel, and a limited market for the resulting products. Several laboratory-scale technologies, such as pH-shift, enzymatic hydrolysis, membrane concentration, and flocculation with centrifugation, were explored in order to extract valuable components from the side-streams. Subsequently, these technologies were scaled-up and tested on a pilot scale. For example, membrane concentration technology facilitated the recovery of valuable molecules from mussel cooking side-streams while reducing environmental impact. Flocculation helped recover proteins and phosphates from process waters, crucial for reducing the organic load of effluents. In addition, decision-making tools were developed to help select and build the most appropriate valorisation strategies, taking into account technical, legal, economic, and environmental aspects. Environmental sustainability was assessed through life cycle assessment, which highlighted the factors that contribute most to the environmental impact of each technology. The results revealed that reducing chemical consumption and improving energy efficiency are key to optimising the environmental performance of the valorisation technologies. The WaSeaBi project outlines a promising path towards sustainable and economically beneficial utilisation of seafood side-streams. By employing innovative technologies, the project not only contributes to reducing waste and environmental impact, but also facilitates the transformation of low-value side-streams into high-value products. In addition, it provides a structured framework to help industry stakeholders make informed decisions on the valorisation of secondary streams. This initiative marks a substantial step towards a more sustainable and economically viable fisheries and aquaculture industry, setting a precedent for future projects aimed at overcoming technological and infrastructural barriers to the valorisation of seafood side-streams.

The artisan production of canned tuna is characterized by generating effluents with high organic and saline loads, which complicates their suitable treatment. The main objective of the LIFE VERTALIM project is to demonstrate the efficiency of a holistic solution (including technical, legislative, social, and environmental aspects) for the controlled integration of food industry wastewater from small and medium enterprises (SMEs) in the urban sanitation system with the compliance of all stakeholders. This work shows the viability of the implementation of low-cost innovative solutions, through the clean and eco-efficient production and wastewater pretreatment for fish canneries. This solution allows on average a reduction of 30% of the wastewater discharges to the environment and a reduction of food losses of up to 0.1%. Moreover, there is a reduction of between 40% and 90% related to high organic load. These results allow the canneries to dispose their pretreated effluents to the urban sanitation system, avoiding the high costs of an industrial wastewater treatment plant (WWTP) to discharge to the river. A better physical-chemical quality in the river waters as a well as the marine water surrounding the urban WWTP have been achieved.