en Fish processing Fish processing پژوهشي Orginal research papers In this study, oil was extracted from the liver and visceral fat of Patin (Pangasianodon hypophthalmus) and refined. The yield of oil after refining was 49.98%. The major yield loss (34.20%) happened during the degumming procedure. Fatty acids found in the crude and refined oil were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6. The dominant saturated, monounsaturated and polyunsaturated fatty acids were C16:0, C18:1 n-9, and C18:2 n-6, respectively. The total amounts of monounsaturated fatty acids did not change significantly during refining procedure (p>0.05), whereas the total amount of saturated and polyunsaturated fatty acids changed significantly (p<0.05). The n-3 to n-6 ratios of crude, degummed, neutralized, bleached, and deodorized oils were 1.11, 1.06, 1.05, 1.02, and 1.01, respectively. Byproduct, Fish oil refining, Fatty acid composition, n-3 fatty acids 457 466 http://jifro.ir/browse.php?a_code=A-10-1272-99&slc_lang=en&sid=1 S Shabanikakroodi 100319475328460013282 100319475328460013282 No A Christianus anniechr@yahoo.com 100319475328460013283 100319475328460013283 Yes C. P Tan 100319475328460013284 100319475328460013284 No Y. B Che Man 100319475328460013285 100319475328460013285 No F Ehteshami 100319475328460013286 100319475328460013286 No