Abstract: The Soxhlet extraction of lipid from Antarctic krill was optimized using one-factor-at-a-time method and
response surface methodology. The lipid yield was studied as a function of solvent type and composition, extraction
temperature and time. The results showed that optimal extraction conditions that resulted in the maximum lipid yield
of 12.32% were as follows: a mixture of hexane and ethanol (3.5:1, V/V) as extraction solvent, temperature 80 ℃, and
time 5.4 h. Gas chromatography analysis showed that the lipid obtained was mainly composed of palmitic acid (C16:0,
28.86%), eicosapentaenoic acid (C20:5n3, 15.48%), oleic acid (C18:1n9c, 12.71%) and docosahexaenoic acid (C22:6, 12.22%).
The unsaturated fatty acid content was above 57.47%, with monounsaturated fatty acids and polyunsaturated fatty acids
accounting for 19.82% and 37.65%, respectively. Therefore, Antarctic krill is a novel source of polyunsaturated fatty acids,
and has high nutritional value and could be widely used as dietary supplements.

Key words: Antarctic krill lipid, fatty acid, Soxhlet extraction, response surface methodology