A circular economy approach for the processing of fisheries waste: Pressure-intensified extraction of valuable products from fish roes

GRANONE, LUIS I.; ISLA NAVEIRA, ROCÍO; LAMAS, DANIELA; FANOVICH, MARÍA A.

Los Cocos, Córdoba

Conferencia; VI Iberoamerican Conference on Supercritical Fluids (PROSCIBA); 2023

Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales

The urgent need for environmental protection and human health preservation is forcingindustrial processes to adopt a circular economy scheme. This transformative approach aims tominimize waste generation, maximize resource efficiency, and foster sustainability. Whileadvancements in technology have revolutionized many industries, the fishing industry has historically lagged behind in adopting these innovations, particularly in the treatment of byproductsand waste recovery. Currently, fish by-products are utilized in the production of fishoil, fishmeal, fertilizers, and feed for pets and livestock [1]. These products often have a limitedeconomic value, which poses challenges in implementing advanced technologies that couldimprove their utilization. Fish viscera contain added-value components that are not fullyexploited. In particular, fish roes stand out for their high content of polyunsaturated fatty acids(PUFAs), especially omega-3 fatty acids, which are highly valuable in the food, cosmetic, andpharmaceutical industries [2]. Furthermore, the roes contain secondary metabolites that protectthemselves from the substantial exposure to UV rays they suffer in their natural environment.These remarkable photoprotective attributes are derived mainly from gadusol and gadusolderivatives, which are highly polar compounds with great potential in the cosmetic industry foruse in sunscreen formulations [2,3]. The conventional methods used to extract these highadded-value components from fish roes often rely on the use of toxic organic solvents, whichpose risks to both the environment and human health. In addition, these procedures involvelengthy and energy-intensive separation steps, further adding to their inefficiency. Therefore,it is crucial to explore efficient and environmentally friendly alternatives. In this context,extraction and fractionation techniques based on pressure-intensified technologies, particularlythose involving the use of supercritical fluids, emerge as an appealing solution [4].In this work, omega-3-rich oil was extracted from dried roes of aquacultured Wreckfish(Polyprion americanus) using supercritical CO2 (scCO2) with and without ethanol as acosolvent. At a temperature and pressure of 313 K and 35 MPa, respectively, an extractionyield of fatty acids of approximately 7.0 % relative to the dry weight of the roes was achieved.According to the chemical profile, the extracted fatty acids consist of 30.0 wt. % saturated fattyacids (SFAs), with palmitic acid (C16:0) as the predominant component (61.0 wt. % of totalSFAs), 36.9 wt. % monounsaturated fatty acids (MUFAs), with oleic acid (C18:1n9) as themain constituent (55.5 wt. % of total MUFAs), and 32.9 wt. % PUFAs, from which omega-3fatty acids account for 92.1 wt. % and omega-6 fatty acids account for 7.9 wt. %. While DHA(C22:6n3) and EPA (C20:5n3) were identified as the primary omega-3 fatty acids (85.5 wt. %and 9.9 wt. % of total omega-3 fatty acids, respectively), linoleic acid (C18:2n6) wasdetermined to be the predominant omega-6 fatty acid (65.4 wt. % of total omega-6 fatty acids).Both the yield and chemical profile of the extracted fatty acids remained similar regardless ofthe addition of ethanol as a cosolvent. However, when pure scCO2 was used for the extraction,the highly polar compound gadusol was not extracted, and hence, its concentration in the roesremained unaltered. In contrast, the addition of ethanol at a cosolvent-to-feed mass ratio of 5g/g resulted in a 30 wt. % reduction in the gadusol content of the roes after the extraction.The proposed approaches allow for the efficient extraction of valuable compounds from fishby-products while minimizing waste generation and environmental impact. Thus, the adoptionof supercritical fluid technologies presents a promising alternative for the fishing industry'stransition toward sustainability.