Extracting omega-3 fatty acids from waste from the fish supply chain to make dietary supplements is one of the most current and promising applications of so-called upcycling. Namely, the ameliorative reuse and valorization of materials that come from ‘side streams’ of production cycles. (1)
A scientific review published in the journal Molecules by Italian researchers at Avantech Group, Palermo, compares available technologies. With a view to encouraging the optimization of processes, including their environmental footprint. (2)
Upcycling omega-3 from the waste of the fish supply chain
Fishing, aquaculture, and seafood processing involve the production of by-products and waste with significant impacts on the environment, as well as on the economics of the supply chains. Reuse and/or recycling of these materials is currently limited, in quantities and destinations essentially confined to the production of feed and pet food. Their disposal in water, on the other hand, causes not insignificant alterations in the marine ecosystem.
The extraction of omega-3 fatty acids from fish supply chain waste represents an opportunity with extraordinary potential impact, on a planetary scale. Taking into account both the huge amounts of the available materials and the crucial value of Omega 3s-the marine ones (EPA+DHA), especially (3)-for human nutrition and health (4,5). However, the processes currently in use are energy-intensive, as well as requiring the use of many chemicals. The challenge is to reduce its environmental impact without losing sight of economic sustainability.
Extraction of fish oils
Fish oils that can be made from the waste products must be extracted and purified. Organic solvents (e.g., hexane) are very efficient but pose risks of residue contamination. The most widely used process on an industrial scale, so-called wet reduction, is structured in the following steps.
1) Cooking, to promote cellular breakdown and release of water and fat content.
2) Pressing, to help separate the liquid fraction (mainly water and oil) from the solid fraction.
3) Decantation and/or centrifugation to separate, at different times, the lipid fraction from the aqueous fraction.
4) Drying, for stabilization of the solid fraction, which must reach a relative humidity of no more than 12 percent.
5) Transesterification of oils, by reaction with alcohols (ethanol in general), to promote separation of fatty acids and increase purification yield.
New Technologies
New technologies-such as microwaves and ultrasound-appear to be very efficient, although still untested. Even more promising, given the selectivity of extraction, are enzymes and supercritical CO2. Which, as it turns out, are able to operate at low temperatures and limit the degradation of sensitive Omega-3s. (6)
Processes using enzymes and supercritical CO2-in addition to solving some of the problems associated with high temperatures and low yields-are also potentially more sustainable and efficient because they avoid the transesterification step.
Omega 3, storage and consumption
The high susceptibility of Omega-3s to oxidation means that an appropriate coating must be found to protect the fats from contact with oxygen and light in order to aid preservation. The material must also be low viscous and sensory neutral, and proteins or polysaccharides are normally chosen for this purpose.
Encapsulation is the main coating technique used with these materials and must be able to ensure the best bioavailability in the gut, limiting the fishy aftertaste as much as possible. This is often accomplished by micro- or nano-level fat reduction using techniques such as spray-drying.
Chemical-free refining, natural antioxidants
Omega-3 refining has the primary function of removing residual contaminants that can be found in fishing waters (e.g., dioxins, polychlorinated biphenyls, heavy metals). As well as the function of removing substances that may compromise the sensory acceptance of products. The use of enzymes and supercritical CO2, alone or in combination with activated carbon, are being tested to refine Omega 3 without the use of chemicals.
It is also important to prevent oxidation, to which fats are very sensitive. To this end, antioxidants are often added, which hinder the formation of radicals and oxidation products that are potentially harmful to health. Since, moreover, synthetic antioxidants themselves have some contraindications, the use of natural antioxidants is becoming more widespread. Such as α-tocopherol (vitamin E), also available in some microalgae as noted. (7)
Interim conclusions
The production of omega-3 fatty acids is an important process because of its economic and nutritional value. The use of waste from the fish supply chain-in a circular economy, or rather Blue Economy, perspective-can increase the sustainability of the process while reducing the environmental impacts associated with its disposal.
Research and development of innovative technologies can complement the overall sustainability of the process.
Fig. 1. See footnote 8
The valorization of fish waste and other fish resources can be further expanded by extracting glycerol, minerals, collagen and gelatin. As well as through the recycling of ‘waste by-products’ for the production of biofuels. The EcoeFISHrent research project, under the Horizon 2020 framework program, aspires to these goals. (9)
#SDG3(Good health and well-being), #SDG12(Sustainable production and consumption), #SDG14(Life below water)
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) Dario Dongo, Andrea Adelmo Della Penna. Upcycling, ameliorative reuse in the food supply chain. GIFT (Great Italian Food Trade). 6.10.21, https://www.greatitalianfoodtrade.it/progresso/upcycling-il-reimpiego-migliorativo-nella-filiera-agroalimentare
(2) Vincenzo Gabriele Alfio, Cosimo Manzo, Raffaella Micillo (2021). From Fish Waste to Value: An Overview of the Sustainable Recovery of Omega-3 for Food Supplements. Molecules 26:1002, https://doi.org/10.3390/molecules26041002 The scientific review was compiled as part of the FOR.TUNA research project, ‘Innovative micronanoformulates for the valorization of bioactive molecules, useful for the health and well-being of the population, obtained from waste products of the fish chain‘ (No. F/050347/01-03/X32, CUP B48I17000510008), in the program Horizon 2020
(3) Dario Dongo, Andrea Adelmo Della Penna. Omega-3 and cardiovascular disease prevention. Mayo Clinic meta-analysis. GIFT (Great Italian Food Trade). 3.2.21, https://www.greatitalianfoodtrade.it/salute/omega-3-e-prevenzione-delle-malattie-cardiovascolari-meta-analisi-di-mayo-clinic
(4) Dario Dongo, Andrea Adelmo Della Penna. Omega 3, polyphenols and other food for thought. Scientific studies. GIFT (Great Italian Food Trade). 18.8.20, https://www.greatitalianfoodtrade.it/salute/omega-3-polifenoli-e-altro-cibo-per-la-mente-studi-scientifici
(5) Dario Dongo, Andrea Adelmo Della Penna. Coronavirus, Omega 3 and the immune system. GIFT (Great Italian Food Trade). 4/13/20, https://www.greatitalianfoodtrade.it/salute/coronavirus-omega-3-e-sistema-immunitario
(6) Deborha Decorti. Cold pasteurization and supercritical CO2. GIFT(Great Italian Food Trade). 3/26/19, https://www.greatitalianfoodtrade.it/tecnologia-alimentare/pastorizzazione-fredda-e-co2-supercritica
(7) Dario Dongo, Andrea Adelmo Della Penna. Microalgae, Euglena gracilis. Superfood with exclusive. GIFT (Great Italian Food Trade). 10.1.21, https://www.greatitalianfoodtrade.it/innovazione/microalghe-euglena-gracilis-superfood-con-esclusiva
(8) Francisco J Marti-Quijal, Fabienne Remize, Giuseppe Meca, Emilia Ferrer, María-José Ruiz, Francisco J Barba (2020). Fermentation in fish and by-products processing: an overview of current research and future prospects. Current Opinion in Food Science, Volume 31, 2020, Pages 9-16, ISSN 2214-7993,
https://doi.org/10.1016/j.cofs.2019.08.001
(9) Dario Dongo, Andrea Adelmo Della Penna. EcoeFISHent, upcycling and blue economy in the fish supply chain. The EU research project. 10/18/21, https://www.greatitalianfoodtrade.it/innovazione/ecoefishent-upcycling-e-blue-economy-nella-filiera-ittica-il-progetto-di-ricerca-ue
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
