The comparison of krill oil extracted through ethanol-hexane method and subcritical method

Area of Science:

• Food Science
• Biochemistry
• Extraction Technology

Background:

• Krill oil (KO) is a valuable source of omega-3 polyunsaturated fatty acids (PUFAs) and astaxanthin.
• Efficient extraction methods are crucial for isolating specific KO components for various applications.
• Current extraction techniques may have limitations in simultaneously isolating different KO fractions.

Purpose of the Study:

• To develop and optimize a safe ethanol-hexane (EH) method for simultaneous extraction of two krill oil fractions.
• To compare the efficacy of the EH method with subcritical butane and butane-dimethyl ether extraction.
• To analyze and characterize the composition of krill oil extracted by different methods.

Main Methods:

• Developed an ethanol-hexane (EH) extraction method with optimized volume ratios (4:6).
• Employed subcritical butane and subcritical butane-dimethyl ether extraction for comparative analysis.
• Utilized the Folch method for total lipid extraction and quantification.
• Analyzed krill oil composition, including astaxanthin, phospholipids (PL), n-3 PUFAs, and fluorine content.

Main Results:

• The EH method, with a 4:6 ethanol-to-hexane ratio, achieved optimal separation of krill oil fractions.
• EH extraction yielded comparable lipid recovery (97.72%) to subcritical butane extraction (97.60%).
• The hexane layer and subcritical butane extract were rich in astaxanthin (910-940 mg/kg).
• The ethanol layer exhibited high phospholipid (47.34%) and n-3 PUFA (45.51%) content with low fluorine (11.17 μg/g).

Conclusions:

• The EH method provides an effective and safe approach for simultaneous krill oil extraction.
• The ethanol fraction of EH-extracted krill oil is a promising source for nutraceutical and antioxidant applications due to its high PL and PUFA content.
• EH extraction offers a viable alternative for producing specialized krill oil ingredients.