درآنها D و A مقايسه روشهاي مختلف استخراج روغن از كبد كوسه ماهي و ماهي كيلكا و مقدار ويتامين هاي

Comparison of different methods of extraction of oil from shark liver and from fish and the amounts of A and D vitamins in them

Background and aim: Shark liver oil and fish oil are good sourese of vitamins A & D. Vitamin A is essential for the immune system , bone growth, night vision and cellular growth. Vitamin D is essential for the absorption of calcium and phosphor, which are required for skeletal growth. Fish and shark liver oil contains essential fatty acids such as EPA and DHA, which may reduce the risk of coronary heart disease. Method: in this research, different methods of extraction of oil (mechanical system, extraction with solvent, alkaline digestion and Bligh & Dyer) from shark (Carcharhinus Macloti) I iver and clupeonolla grimi were applied and compared. Vitamin A and D were determined by pharmacological methods. Results: The results showed that Bligh & Dyer was the best method due to higher stability of vitamins. More than 45% w/w oil was obtained from 100g of liver by this method. This method was not suitable for clupeonolla grimi because of less oil content. The mechanical method was preferred for low quality oil with lower price. Conclusion: The shark liver has a high percentage of A and D vitamins and could be used as a raw materials for pharmaceutical aims. The amounts of vitamin D3 and oil extracted from shark liver, were higher than cultrirntris fish, but its vitamin A content was lower than the cultrirntris fish oil.