Lipid extraction processes

1. A high-efficiency process for extracting lipids from a krill biomass comprising:

mixing said krill biomass with a protic solvent having a concentration of from 90% to 97% at a temperature of from about 5° C. to about 65° C. to provide a solvent and krill biomass mixture, wherein said krill biomass is selected from the group consisting of cooked krill meals and krill hydrolysate meals,

separating a crude lipid solution from the solvent and krill biomass mixture, wherein about 70 to 90% w/w of the total available lipids in the krill biomass are extracted;

desalting said crude lipid solution;

fractionating said desalted crude lipid solution by adjusting the dry matter content of said crude lipid solution to from about 10% to 40% while maintaining the concentration of the protic solvent at from about 65% to 98% and holding said solution at about 0° C. to about 20° C. so that phospholipids in said solution partition into a light phase and neutral lipids in said solution partition into a heavy phase; and

separating said heavy and light phases.

2. The method of claim 1 , wherein said krill biomass is selected from the group consisting of krill meal, krill coagulum and fresh frozen krill.

3. The method of claim 2 , wherein said krill meal is selected from the group consisting of cooked krill meals and krill hydrolysate meals.

4. The method of claim 3 , wherein said cooked krill meal has a moisture content of from about 5% to 8% and is from about 12% to 24% w/w lipids.

5. The method of claim 1 , wherein said heavy and light phases are separated by centrifugation.

6. The method of claim 5 , wherein said centrifugation step uses a cryocentrifuge.

7. The method of claim 1 , wherein the concentration of said protic solvent during said fractionating step is from about 92% to about 98% w/w.

8. The method of claim 1 , wherein the concentration of said protic solvent during said fractionating step is from about 80% to about 90% w/w.

9. The method of claim 1 , further comprising the step of removing said solvent from said light phase to provide a concentrated phospholipid composition comprising from about 50% to about 85% w/w phospholipids and wherein the composition has one or more of the following properties:

a triglyceride content of from about 5% to 35% w/w;

a free fatty acid content of from about 4% w/w to about 11% w/w;

a lysophospholipid content of from about 0.8% w/w to about 7.0% w/w;

an inorganic salt content of less than about 0.2% w/w;

a nitrogen content of less than about 2 mg N/100 g;

a copper content of less than about 2 ppm;

an arsenic content of less than about 3 ppm;

an ethyl ester content of less than about 1% w/w;

a viscosity of from about 500 to 1800 mPas at 35° C.; and

an astaxanthin ester content of less than about 100 ppm.

10. The method of claim 1 , further comprising the step of removing said solvent from said heavy phase to provide a concentrated neutral lipid composition comprising from about 80% to about 95% w/w neutral lipids and wherein the composition has one or more of the following properties:

a phospholipid content of from about 4% to 15% w/w;

a free fatty acid content of from about 1% w/w to about 8% w/w;

a lysophospholipid content of from about 0.1% w/w to about 2.0% w/w;

an inorganic salt content of less than about 0.2% w/w;

a nitrogen content of less than about 2 mg N/100 g;

a copper content of less than about 2 ppm;

an arsenic content of less than about 3 ppm;

an ethyl ester content of less than about 1% w/w;

a viscosity of less than about 400 mPas at 25° C.; and

an astaxanthin ester content of greater than about 300 ppm.

11. The method of claim 10 , wherein said concentrated neutral lipid composition comprises from about 300 to 1200 ppm astaxanthin esters.