Search Results (24)

African catfish (Clarias gariepinus, AC) is one of the most widely farmed freshwater fish species in Central Europe. Processing operations generate up to 55% by-products (BPs), predominantly carcasses rich in proteins, lipids, and minerals. This study develops a comprehensive valorization process for ACBPs to recover gelatin, protein hydrolysate, fish oil, and pigments. The processing protocol consisted of sequential washing, oil extraction, demineralization, and biotechnological treatment to disrupt the collagen quaternary structure. A two-factor experimental design was employed to optimize the processing conditions. The factors included the extraction temperatures of the first (35–45 °C) and second fraction (50–60 °C). We hypothesized that enzymatic conditioning, combined with sequential hot-water extraction, would yield gelatin with properties comparable to those of mammalian- and fish-derived gelatins, while enabling a near-zero-waste process. The integrated process yielded 18.2 ± 1.2% fish oil, 9.8 ± 2.1% protein hydrolysate, 1.7 ± 0.7% pigment extract, and 25.3–37.8% gelatin. Optimal conditions (35 °C/60 °C) produced gelatin with gel strength of 168.8 ± 3.6 Bloom, dynamic viscosity of 2.48 ± 0.02 mPa·s, and yield of 34.76 ± 1.95%. Life cycle assessment (LCA) identified two primary environmental hotspots: water consumption and energy demand. This near-zero-waste biorefinery demonstrates the potential for comprehensive valorization of aquaculture BPs into multiple value-added bioproducts. Full article

This study describes the development of a biodegradable biopolymer formulated from protein–polysaccharide matrices enriched with antioxidant hydrolysates obtained from Cyprinus carpio by-products. The hydrolysates were produced through targeted enzymatic hydrolysis using plant-derived proteases, yielding peptide fractions with relevant radical-scavenging activity. Molecular characterization (DSC) confirmed the presence of thermal stability suitable for cold-chain applications, while the resulting biopolymer displayed flexible and cohesive structural behavior. The material was evaluated as an edible coating for raspberries stored at 4 °C. Coatings containing the hydrolysates, particularly those generated with bromelain, more effectively slowed physicochemical deterioration, modulated oxidative reactions, and helped to preserve nutritional quality during storage. These findings indicate that integrating bioactive peptide hydrolysates into biodegradable polymer networks enhances their functional performance, offering a sustainable approach for food preservation and valorization of agro-aquaculture residues. Full article

The increasing demand for sustainable aquafeeds necessitates the development of alternative protein sources that support both economic efficiency and ecological responsibility. This study evaluates the potential of using hempseed meal (a nutrient-dense agro-industrial by-product) as a functional ingredient in carp aquaculture diets. The paper presents a proof-of-concept evaluation demonstrating the potential of hempseed meal as a circular bio-ingredient that aligns with the principles of sustainable aquaculture, rather than providing a comprehensive assessment of its long-term physiological effects on fish. A 90-day feeding trial was conducted under controlled pond conditions to assess the effects of graded hempseeds meal inclusion levels on growth performance, feed utilization, and environmental sustainability indicators for three Cyprinus carpio varieties. Four isonitrogenous and isoenergetic diets were formulated: a control diet (R1) based on conventional plant protein sources such as soybean and pea meal, and three experimental diets containing 5%, 10%, and 20% hempseed meal (R2–R4). Growth indices including absolute weight gain (WG), average daily gain (ADG), specific growth rate (SGR), and feed conversion ratio (FCR) were determined, and data was analyzed via two-way ANOVA with Tukey HSD post hoc testing. Results indicated that 10% hempseed meal inclusion produced optimal growth responses, improving specific growth rate by 12.6% and reduced feed conversion ratio by 10.8% compared to the control. The most pronounced effects were observed for Frăsinet carp variety (SGR 1.23%·day⁻¹; FCR 1.39). Environmental assessments demonstrated that substituting conventional protein sources (soybean and pea meal) with hempseed meal at 20% inclusion valorized 200 kg of hemp press cake per ton of feed, reduced conventional protein use by 33.3%, diverted up to 80% of waste from disposal. These findings validate hempseed meal as a sustainable, cost-effective, and nutritionally viable alternative to conventional protein sources in freshwater aquaculture, advancing circular bioeconomy strategies and supporting low-carbon fish production systems. Full article

Tambatinga (Colossoma macropomum × Piaractus brachypomus), a hybrid Amazonian fish recognized for its superior growth performance, represents a valuable and sustainable source of collagen-rich raw material. Due to its tropical origin, the species’ skin may contain higher levels of amino acids, which can enhance the functional and structural properties of gelatin derived from it. The valorization of fish processing residues for biopolymer production not only mitigates environmental impacts but also reinforces the principles of the circular economy within aquaculture systems. This study explores the development of biopolymer films from Tambatinga skin, an abundant by-product of Brazilian aquaculture. The skins were cleaned and subjected to a hot water–acid extraction process to obtain gelatin. The extracted gelatin exhibited high proline and hydroxyproline contents (12.47 and 9.84 g/100 g of amino acids, respectively) and a Bloom strength of 263.9 g, confirming its suitability for film formation. Films were prepared using 2 g of gelatin per 100 g of film-forming solution, with glycerol added at 10 and 20 g/100 g of gelatin. The resulting films were transparent, flexible, and showed uniform surfaces. Increasing the glycerol concentration reduced tensile strength (from 59.4 to 37.9 MPa) but improved elongation at break (from 116% to 159.1%) and modified the films’ thermal behavior. Moreover, Tambatinga gelatin films demonstrated excellent UV-blocking performance (below 300 nm) and lower water vapor permeability compared to other gelatin-based films reported in the literature. These findings highlight the potential of fish skin—typically regarded as industrial waste—as a renewable and high-value raw material for the production of sustainable biopolymers. This approach supports resource efficiency, waste reduction, and the broader goals of sustainable development and circular bioeconomy. Full article

Background: The extensive use of antibiotics in aquaculture has raised serious concerns, emphasizing the need for sustainable and natural alternatives. This study evaluated the potential of red dragon fruit (Hylocereus polyrhizus) juice by-products (RJB) as a functional feed additive for juvenile red seabream (Pagrus major). Materials and Methods: The bioactive composition and antioxidant capacity of RJB were analyzed, and five experimental diets containing 0, 0.2, 0.4, 0.8, and 1% RJB were fed to fish for 56 days. Results: Growth performance, feed utilization, body composition, antioxidant enzyme activities, and lysozyme activity were evaluated. RJB contained substantial levels of phenolic and flavonoid compounds and exhibited strong radical-scavenging activity. Dietary inclusion of up to 1% RJB did not significantly affect growth, feed efficiency, or plasma biochemistry. However, fish fed the 1% RJB diet showed increased catalase and glutathione levels, significantly enhanced lysozyme activity, and improved survival following Edwardsiella tarda infection. Conclusion: These results demonstrate that RJB can be safely incorporated into marine fish diets to enhance antioxidant capacity and innate immune defense. The valorization of fruit-processing by-products such as RJB offers a promising strategy for developing antibiotic-free and sustainable aquaculture practices. Full article

The growing demand for sustainable food sources requires the efficient use of aquaculture by-products. This study aimed to optimize enzymatic hydrolysis conditions for the simultaneous recovery of fish protein hydrolysate (FPH) and oil from rainbow trout (Oncorhynchus mykiss) processing by-products. Hydrolysis was performed at different temperatures (30–50 °C), enzyme concentrations (0.5–1.5%), and durations (30–90 min), and the optimal conditions were determined as 40 °C, 1% enzyme concentration, and 60 min. Under these conditions, oil yield reached 11.46%, while quality indices remained within acceptable limits (peroxide value: 1.78–3.47 meq O₂/kg; thiobarbituric acid reactive substances: 0.41–1.41 mg MDA/kg; free fatty acids: 0.27–4.12%). Fatty acid analysis revealed 22.5% saturated, 46.31% monounsaturated, and 23.52% polyunsaturated fatty acids, including notable levels of EPA and DHA. The protein hydrolysates obtained under optimized conditions contained 22.61% protein and essential amino acids, accounting for 52.4% of the total amino acid content, confirming their high nutritional value. Overall, the findings demonstrate that rainbow trout by-products can be effectively valorized through enzymatic hydrolysis to produce oil and protein hydrolysates of acceptable quality, which may serve as alternative ingredients for food and feed applications. Full article

This review examines the current state of the supply chain management for Dicentrarchus labrax (sea bass) and Sparus aurata (sea bream), two key commercial fish species in the Mediterranean. It provides a comprehensive analysis of sustainable innovations in aquaculture, processing, and packaging, with particular attention to circular economy-based biopreservation techniques. A major focus is on the Integrated Multi-Trophic Aquaculture (IMTA) system, an advanced farming approach that enhances sustainability, promotes circular resource utilization, and improves fish welfare. By fostering ecological balance through the co-cultivation of multiple species, IMTA contributes to the overall quality of fish products for human consumption. Beyond aquaculture, the review addresses the critical challenge of food loss, which stems from the high perishability of fish during storage and processing. In this regard, it highlights recent advancements in biopreservation strategies, including the application of antagonistic microorganisms, their metabolites, and plant-derived extracts. Particular attention is given to the development of edible antimicrobial films, with a focus on the valorization of citrus processing by-products for their production. By centering on innovations specific to the Mediterranean context, this review underscores that a holistic, integrative approach to supply chain management is essential for transitioning the aquaculture sector toward greater efficiency and sustainability. Full article

Aquaculture wastewater treatment not only assists in alleviating the scarcity of clean water for daily usage and environmental pollution, but also generates valuable byproducts. This paper aims to review the generation of wastewater from the aquaculture sector, its characteristics, and available treatment technologies, while comprehensively discussing the adoption of a biocircular economy approach through waste valorization. With rich nutrients, such as nitrogenous compounds, and the presence of phosphorus in the aquaculture effluent, these aspects could be explored and valorized into biofertilizers, broadening their application in aquaponics and hydroponics, as well as in algae and daphnid cultivation. Biofertilizer can also be used in agriculture because it contains essential elements needed by plants. Thus, methods of converting nutrients into biofertilizers in terms of sludge recovery can be accomplished via anaerobic and aerobic digestion, drying, composting, and vermicomposting. Moving forward, aquaculture effluent recovery is addressed under the biocircular economy by re-engaging aquaculture wastewater effluents into the production cycle. The enhancement of aquaculture effluents and biomass for uses such as aquaponics, hydroponics, algae cultivation, daphnid co-cultivation, and biofertilizers presents valuable opportunities for nutrient recovery while ensuring that non-toxic wastewater can be safely discharged into external water bodies. This approach has the potential to revolutionize wastewater treatment in aquaculture, shifting the economic model of wastewater management from a linear system to a circular, more sustainable one. Full article

In response to increasing food waste and the necessity for sustainable resource utilization, this study evaluated the effectiveness of black soldier fly (Hermetia illucens) larvae in converting a mixture of coffee and meat residues into protein-rich meal suitable for animal feed. A two-component mixture design optimized the substrate composition, followed by model validation and a comprehensive nutritional characterization of the larvae-derived protein. The larval meal contained 30–39 g of protein per 100 g (dry basis). The results indicated that increasing the meat residue content to 35% in the substrate maximized the protein yield. The optimized larval meal contained 52.9 g of protein per 100 g (dry basis) and favorable parameters such as moisture and fat, demonstrating a nutrient profile suitable for aquaculture feed. These findings suggested that Hermetia illucens larvae could convert agro-industrial by-products into high-quality protein. Coffee and meat residues served as suitable substrates for larval growth, supporting proper metabolic development and yielding a high bioconversion rate. This work contributes to the constant efforts in food waste valorization by integrating nutrient recovery processes into circular economy principles. Full article

This study aimed to improve the conventional procedure of alginate isolation from the brown seaweed (Laminaria digitata L.) biomass and investigate the possibility of further valorization of the ethanolic fraction representing the byproduct after the degreasing and depigmentation of biomass. The acid treatment of biomass supported by ultrasound was modeled and optimized regarding the alginate yield using a response surface methodology based on the Box–Behnken design. A treatment time of 30 min, a liquid-to-solid ratio of 30 mL/g, and a treatment temperature of 47 °C were proposed as optimal conditions under which the alginate yield related to the mass of dry biomass was 30.9%. The use of ultrasonic radiation significantly reduced the time required for the acid treatment of biomass by about 4 to 24 times compared to other available conventional procedures. The isolated alginate had an M/G ratio of 1.08, which indicates a greater presence of M-blocks in its structure and the possibility of forming a soft and elastic hydrogel with its use. The chemical composition of the ethanolic fraction including total antioxidant content (293 mg gallic acid equivalent/g dry weight), total flavonoid content (14.9 mg rutin equivalent/g dry weight), contents of macroelements (the highest content of sodium, 106.59 mg/g dry weight), and microelement content (the highest content of boron, 198.84 mg/g dry weight) was determined, and the identification of bioactive compounds was carried out. The results of ultra high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry analysis confirmed the presence of 48 compounds, of which 41 compounds were identified as sugar alcohol, phenolic compounds, and lipids. According to the 2,2-diphenyl-1-picrylhydrazyl assay, the radical scavenging activity of the ethanolic fraction (the half-maximal inhibitory concentration of 42.84 ± 0.81 μg/mL) indicated its strong activity, which was almost the same as in the case of the positive control, synthetic antioxidant butylhydroxytoluene (the half-maximal inhibitory concentration of 36.61 ± 0.79 μg/mL). Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus) were more sensitive to the ethanolic fraction compared to Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei). The obtained results indicated the possibility of the further use of the ethanolic fraction as a fertilizer for plant growth in different species and antifouling agents, applicable in aquaculture. Full article

The valorization of aquaculture/fishery processing by-products, as well as unavoidable/unwanted catches and discards in Greece, is currently an underutilized activity despite the fact that there are several best practices in Northern Europe and overseas. One of the main challenges is to determine whether the available quantities for processing are sufficient to warrant the valorization of discards and fish side streams. This is the first attempt to systematically record and analyze the available quantities of fish by-products and discards in Greece spatially and temporally in an effort to create a national exploitation Master Plan for the valorization of this unavoidable and unwanted biomass. A thorough survey conducted within the VIOAXIOPIO project unveiled a substantial biomass of around 19,000 tonnes annually that could be harnessed for valorization. Furthermore, the production of various High-Added-Value Biomolecules (HAVBs) was investigated and experimental trials were conducted to assess the potential yields, with the collected data used to formulate four valorization scenarios. Full article

The green tips of Salicornia ramosissima are used for human consumption, while, in a production scenario, the rest of the plant is considered a residue. This study evaluated the potential of incorporating salicornia by-products in diets for juvenile European seabass, partially replacing wheat meal, aspiring to contribute to their valorization. A standard diet and three experimental diets including salicornia in 2.5%, 5% and 10% inclusion levels were tested in triplicate. After 62 days of feeding, no significant differences between treatments were observed in fish growth performances, feeding efficiency and economic conversation ratio. Nutrient digestibility of the experimental diets was unaffected by the inclusion of salicornia when compared to a standard diet. Additionally, salicornia had significant modulatory effects on the fish muscle biochemical profiles, namely by significantly decreasing lactic acid and increasing succinic acid levels, which can potentially signal health-promoting effects for the fish. Increases in DHA levels in fish fed a diet containing 10% salicornia were also shown. Therefore, the results suggest that salicornia by-products are a viable alternative to partially replace wheat meal in diets for juvenile European seabass, contributing to the valorization of a residue and the implementation of a circular economy paradigm in halophyte farming and aquaculture. Full article

Marine (blue) biotechnology is an emerging field enabling the valorization of new products and processes with massive potential for innovation and economic growth. In the Mediterranean region, this innovation potential is not exploited as well as in other European regions due to a lack of a clear identification of the different value chains and the high fragmentation of business innovation initiatives. As a result, several opportunities to create an innovative society are being missed. To address this problem, eight Northern Mediterranean countries (Croatia, France, Greece, Italy, Montenegro, Portugal, Slovenia and Spain) established five national blue biotechnology hubs to identify and address the bottlenecks that prevent the development of marine biotechnology in the region. Following a three-step approach (1. Analysis: setting the scene; 2. Transfer: identification of promising value chains; 3. Capitalization: community creation), we identified the three value chains that are most promising for the Northern Mediterranean region: algae production for added-value compounds, integrated multi-trophic aquaculture (IMTA) and valorization aquaculture/fisheries/processing by-products, unavoidable/unwanted catches and discards. The potential for the development and the technical and non-technical skills that are necessary to advance in this exciting field were identified through several stakeholder events which provided valuable insight and feedback that should be addressed for marine biotechnology in the Northern Mediterranean region to reach its full potential. Full article

There is a significant potential to increase the sustainability of the fishing and aquaculture industries through the maximization of the processing of byproducts. Enzymatic hydrolysis provides an opportunity to valorize downstream fish industry byproducts for the production of protein hydrolysates (FPH) as a source of bioactive peptides (BAP) with health benefits. Deteriorative oxidative reactions may occur during the enzymatic hydrolysis of byproducts, influencing the safety or bioactivities of the end product. Lipid oxidation, autolysis mediated by endogenous enzymes in viscera, protein degradation, and formation of low-molecular-weight metabolites are the main reactions that are expected to occur during hydrolysis and need to be controlled. These depend on the freshness, proper handling, and the type of byproducts used. Viscera, frames, trimmings, and heads are the byproducts most available for enzymatic hydrolysis. They differ in their composition, and, thus, require standardization of both the hydrolysis procedures and the testing methods for each source. Hydrolysis conditions (e.g., enzyme type and concentration, temperature, and time) also have a significant role in producing FPH with specific structures, stability, and bioactivity. Protein hydrolysates with good safety and quality should have many applications in foods, nutraceuticals, and pharmaceuticals. This review discusses the oxidative reactions during the enzymatic hydrolysis of byproducts from different fish industry sectors and possible ways to reduce oxidation. Full article

Alzheimer’s disease (AD) is a complex and progressive disease, which affects millions of people around the world. Despite the many efforts over the years to find efficient therapeutics, there is no cure yet. Nonetheless, many compounds have been proven to decrease Alzheimer’s symptoms. After a short overview of the hypotheses considered in AD drug development and the drugs approved for AD treatment, which lead to symptom release, we focus on the valorization of natural marine sources that decrease AD symptoms, particularly on docosahexaenoic acid (DHA), an important component in membrane phospholipids and the most abundant n−3 polyunsaturated fatty acids (PUFA) found in gray matter of the brain and in retina and on the DHA-containing phospholipids (DHA-PLs) present in marine sources, namely fish, krill, mollusks and in fisheries and aquaculture by-products. DHA-PLs’ bioactivities are presented, namely their properties in anti-neurodegeneration, neuroinflammation, as anticancer agents, as well as their benefits to obesity and visual problems. Fisheries and aquaculture by-products are also highlighted as they have a high content of DHA and DHA-rich phospholipids, can be extracted by green methodologies and should be considered in a circular economy for a healthy sustainable future. Full article