Mjøs, Svein AreGrung, BjørnXiao, Liping2018-07-022018-07-022010-02-232010http://hdl.handle.net/10400.1/10737The extraction efficiency of Soxhlet, acid hydrolysis and Bligh and Dyer were evaluated by using direct methylation on extracts and residues for calculating the mass balance of fatty acids for eight marine powders (fishmeals, krillmeals, cod filet, salmon filet and herring roe). The results show that Soxhlet gave lowest extracted fatty acid content, especially for the samples which contain a high amount of phospholipid. Acid hydrolysis and Bligh and Dyer extract gave comparable extracted fatty acid contents with direct methylation. The mass balance of fatty acids in extract and residue is close to 100% for the three extraction methods which indicate that fatty acid was not lost during the extraction procedures. The difference of extracted fatty acids is mainly due to the different extracting efficiency. The gravimetric lipid has limited correlation with total fatty acids, especially for Soxhlet. Analyses of the fatty acid profiles showed that the Soxhlet extracts were different from the others. Extracts from the acid hydrolysis and Bligh and Dyer methods had similar fatty acid profiles as the direct methylation method. The precision of fatty acid analysis by direct methylation method for marine powders were also validated. The coefficient of variation was 5.11% for solid samples and 1.21% for liquid sample.engDirect methylationOne-step methylationFatty acidsSoxhletAcidHydrolysisBligh and dyermaster thesis