The effects of 6 solvent combinations (Folch, acetone/ethanol [1:1, v/v], ethanol [95%, v/v], n-hexane/ethyl acetate [7:3, v/v], n-hexane/ethanol [10:1, v/v], and isopropanol alcohol [95%, v/v] with different polarities on the quality characteristics of Antarctic krill oil (AKO) extracted from Antarctic krill were investigated in this study. The relationship between endogenous active substances and oxidative stability was also explored. There was a significant positive correlation between solvent polarity and AKO yield (r = 0.91, p < 0.05), a significant positive correlation with total tocopherols (r = 0.84, p < 0.05) and a weak correlation with astaxanthin (r = 0.53). In addition, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in AKO were mostly located in phosphatidylcholines, lysophosphatidylcholine, phosphatidylethanolamine and lysophosphatidylethanolamine. ethanol (95%, v/v) had the highest efficiency of glycerophospholipids (34.39%), EPA (20.83%) and DHA (9.61%). For liposolubility trace substances, astaxanthin were extracted most efficiently with Folch (283.49 μg/g) and acetone/ethanol (1:1, v/v, 264.58 μg/g), whereas tocopherols were extracted most efficiently with ethanol (95%, v/v, 114.29 μg/g). Astaxanthin, tocopherol and phosphatidylcholines were closely related to the oxidative stability of AKO. Astaxanthin in AKO showed a significant (p < 0.05) positive correlation with ABTS· scavenging capacity, whereas tocopherol and phosphatidylcholines showed a significant (p < 0.05) dose-effect relationship with total reducing power.
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