Standardization of Extraction Process Parameters and Solvent Reuse for Sustainable Extraction of Omega-3-Rich Flaxseed Oil

Abstract

Growth emphasizing on health and wellness (in terms of immunity) has highlighted the importance of dietary bioactives like omega-3 fatty acids. Flaxseed is a rich source of omega-3 fatty acids, particularly alpha-linolenic acid (ALA). This work focused on optimization of Soxhlet extraction parameters to maximize oil yield and evaluation of solvent recovery and reusability across multiple extraction cycles. Soxhlet extraction parameters, including solvent type (hexane, ethanol, ethyl acetate), extraction time (8, 12, 16 h), and solid-liquid ratio (1:2.5 to 1:15) were systematically investigated. Hexane proved most effective among the solvents tested, yielding 40.48 ± 2.25% oil at an extraction time of 8 h and a solid-liquid ratio 1:10, followed by ethyl acetate and ethanol. Notably, a yield comparable to that obtained at 16 h with 1:2.5 ratio (43.84 ± 1.51%) was achieved in 8 h by optimizing the solid-liquid ratio to 1:10. Hexane was recovered with an average recovery of ~72% and was reused successfully for up to 10 cycles without significant loss in oil yield or quality. Gas chromatography (GC-FID) confirmed consistent fatty acid composition across all extraction cycles. FT-IR analysis showed no significant changes in functional groups, with only minor variations in peak intensities at later cycles and no new peaks detected. Consistent physicochemical properties, including refractive index, acid value, and free fatty acid content, further confirmed the oil stability. The optimized process provides a sustainable and efficient extraction protocol for omega-3-rich flax oil extraction aligned with industrial cost-efficiency and green chemistry principles.