FATTY ACIDS PROFILE, ANTIOXIDANT AND PHYSICOCHEMICAL PROPERTIES OF MARINE FISH OIL EXTRACTED BY MECHANICAL METHOD

ABSTRACT This study investigated the yield, fatty acid profile, antioxidant activity, and physicochemical properties of oils extracted from three fish species—Chrysichthys nigrodigitatus (WI), Channa spp. (WO), and Trachurus trachurus (WT)—using the mechanical wet rendering method. Fresh samples were processed at 90°C, pressed, and the oil clarified by centrifugation. Yields were determined, fatty acids analyzed via GC-FID, antioxidant activity assessed using phenolic, flavonoid, DPPH, FRAP, hydroxyl radical scavenging, and iron-chelating assays, and physicochemical parameters measured by standard AOAC methods. Results showed WT had the highest oil yield (3.24%), followed by WO (1.79%) and WI (0.88%). Acid values ranged from 1.51–2.02 mg KOH/g, peroxide values from 3.75–5.46 Meq/kg, iodine values from 96.55–111.99 g I₂/100g, and saponification values from 159.53–179.60 mg KOH/g. Antioxidant profiles varied: WI had the highest phenolic content (0.37 mg GAE/g) and iron-chelating activity, WO showed the greatest DPPH (51.34%), FRAP (3.38 mg TE/g), and hydroxyl radical scavenging, while WT had the highest flavonoid content (0.59 mg QE/g). Fatty acid analysis revealed high polyunsaturated fatty acids (PUFA), particularly arachidonic acid (\~20.8%), alongside significant levels of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The findings highlight species-specific differences: WT offers high yield and balanced composition, WO provides PUFA-rich oil with strong antioxidant potential, and WI delivers more stable oil with superior metal-chelating properties. These results suggest that wet rendering can produce nutritionally valuable fish oils suitable for dietary, pharmaceutical, and industrial applications, with selection of species tailored to desired yield, composition, and stability.