Methods of extraction composition and stability of vitamin A and other components in dogfish (Squalus acanthias) liver oil

Oil was extracted from dog fish (Squalus acanthias) livers by the Bligh and Dyer, Soxhlet and steaming extraction methods. Oil yields using the steaming method (22% ww) were lower than from the solvent extraction methods (68% ww). The vitamin A content of the oil produced by steaming was 54 mg retinol/100 g oil, and slightly higher (62–68 mg/100 g) contents were recorded in the solvent extracted oils. igh and Dyer extraction produced an oil containing 12% phospholipid, much higher than the 4% via the Soxhlet and 1 % in the steaming extractions. The level of squalene (40 mg/100 g) in the oil produced by steaming was higher than in the other oils (28 and 32 mg). Concentrations of vitamin E and cholesterol were similar in all three oils at approximately 25 mg tocopherol/100 g and 1.1 g cholesterol/100 g, respectively. ere stored under air at room temperature in half filled dark coloured bottles. Although highest PVs were observed in the stored Bligh and Dyer-extracted oils, the highest apparent loss of vitamin A (30% in 3 weeks) occurred in the oil extracted by steaming.