Comparative Effects of Solvent and Thermomechanical Extraction on the Composition and Nutraceutical Quality of Fontitrygon margarita Liver Oil

The valorization of marine byproducts offers a sustainable route to generate high-value lipids with functional and nutritional relevance. This study compared cold solvent extraction with two thermomechanical techniques, exudation and cooking-pressing, to determine how extraction conditions influence the composition and nutraceutical quality of Fontitrygon margarita liver oil. Exudation produced the highest extraction yield (51.94%), followed by solvent extraction (40.86%) and cooking-pressing (25.79%). Solvent extraction preserved higher proportions of long-chain n-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA, 7.01%) and docosahexaenoic acid (DHA, 6.53%), and yielded more favorable nutritional quality indices (AI = 0.51, TI = 0.47, h/H = 2.04). It also produced oils with stronger antioxidant activity, as reflected by lower DPPH IC50 values (18.15 ppm), greater inhibition of COX-1 and COX-2, reduced erythrocyte lipid peroxidation, and higher catalase-related responses in ex vivo assays. Cooking-pressing yielded intermediate outcomes while providing the highest polyphenol content (1.36 mg GAE/g oil). Anti-inflammatory responses varied according to the assay, with thermomechanically extracted oils exhibiting membrane-stabilizing effects comparable to those of solvent-extracted oil under heat-stress conditions. Overall, the extraction method strongly influenced fatty acid composition, oxidative stability, phytochemical retention, and biological activity. Among the methods evaluated, solvent extraction provided the most favorable overall nutraceutical profile despite practical limitations associated with solvent use.