Hydrophobic Deep Eutectic Solvents (HDES) as an Alternative for the Extraction of Omega Fatty Acids of By-Products of <em>Octopus maya</em>

This study evaluated the use of HDES for omega-3 recovery from mantles (by-products) of O. maya, an endemic species of the Yucatán Peninsula. A 2×3×2 factorial design was applied to assess the effect of: (1) the hydrogen bond acceptor (HBA) of the HDES (menthol or eucalyptol), with oleic acid as the hydrogen bond donor; (2) the molar ratio (MR) (1:1, 1:2, or 2:1); and (3) ultrasound-assisted extraction time (30 or 60 min) in omega-3 content, determined by UV–Vis spectrophotometry, viscosity and color characterization. Samples with the highest omega-3 content were selected and their composition was confirmed by FTIR, Raman spectroscopy and gas chromatography. Significant differences (p &lt; 0.05) were observed better with HBA and MR factors (menthol or eucalyptol) in omega-3 content; the highest omega-3 values (0.63–0.83%), were obtained with eucalyptol-based HDES (while menthol-based systems showed lower contents (≤0.70%), suggesting better extraction performance for eucalyptol. All extracts showed Newtonian behavior with viscosities between 0.011 and 0.036 Pa·s, with eucalyptol formulations presenting the lowest values (0.011–0.023 Pa·s). Fatty acid pro-filing showed greater affinity for polyunsaturated fatty acids, mainly omega-6 (23.45–27.91%), and lower affinity for saturated fatty acids such as palmitic and stearic acids, indicating that HDES are a sustainable alternative for the selective extraction.