Proximate composition and fatty acid profile of Himantura marginata (Blackedge whipray) liver oil

Fish oils are well-known sources of polyunsaturated fatty acid (PUFA) and docosahexaenoic acid (DHA), widely used in the food industry as nutritional supplements, as well as in the pharmaceutical industry. In this present study, ray fish Himantura marginata (Blackedge whipray) were collected from Nagapattinam fishing harbour, and oil from the livers was extracted by the BUME method. The percentage of oil yield was recorded as 83 ± 2.8 from the above method. The proximate composition such as total protein (26.51 ± 0.34%), crude fat (7.58 ± 0.16%), moisture (7.08 ± 0.13%) and ash content (8.63 ± 0.45%) was calculated by standard AOAC method. The physical properties were recorded as follows: specific gravity at 28 ℃, 1.03 ± 0.02 g cm −3 ; refractive index, 1.430; saponification value, 176.90 ± 1.24 mg KOH/g oil; iodine value, 148.79 ± 2.07 mg I2/100 g; density, 0.927 ± 0.06 g/mL; carotenes, 3.68 mg/100 g oil; α-tocopherol 9.34 mg/100 g oil; and colour, yellowish. Fatty acid profiling of the liver oil was performed by using gas chromatography with flame ionization detector (GC-FID); it exhibited 22 different types of fatty acids including saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The elemental analysis of liver oil was performed by inductively coupled plasma mass spectrometry, and the values are analysed in triplicate.