Method for refining and manufacturing fats and oils containing polyunsaturased fatty acids

摘要

A method of refining and manufacturing a fat and oil containing polyunsaturated fatty acids which prevents production of peculiar fishy smells when such a fat and oil is added to food materials and while it is stored by preventing oxidation of PUFA's and restraining conversion of odor-emanating precursors into odor-emanating substances. A fat and oil, such as a marine animal oil, containing polyunsaturated fatty acids with 18 or more carbon atoms and three or more double bonds such as EPA and DHA is alkali refined and bleached. The thus alkali refined and bleached fat and oil is refined by bringing 100 parts by weight of it into contact for 10 minutes or more at 5-80 DEG C with not less than 0.1 part by weight of powdered or granulated diatomaceous earth formed by calcining with a flux added such as sodium carbonate or sodium chloride. The fat and oil thus obtained is filtered and deodorized by steam distillation under vacuum.