1. A counter-current extraction process involving a plurality of mixing and separation stages for fractionating a phospholipid-containing feed material into two or more fractions enriched in one or more phospholipids, comprising the following steps: (a) contacting the phospholipid-containing starting material under agitation with an extractant comprising an aliphatic alcohol selected from C1 to C3 alcohols and mixtures thereof for a period of time sufficient to effectuate the transfer of at least a fraction of the phospholipids into the extractant; (b) separating the obtained mixture into a phospholipid-enriched extract from a residual raffinate by a process comprising applying centrifugal forces, wherein the phospholipid-enriched extract from each separation stage is at least in part returned to the previous, or further upstream mixing stages, and wherein a final phospholipid -enriched extract is separated from a first residual raffinate.
2. The process as claimed in claim 1, wherein in (a) the phospholipid-containing starting material is contacted with the extractant in a co-current or counter-current mixing operation.
3. The process as claimed in claim 1 or claim 2, wherein the extracted phospholipids comprise one or more of phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl Inositol (PI) and/or phosphatidic acid (PA).
4. The process as claimed in any one of claims 1 to 3, wherein the final raffinate phase comprises less than 12 % by weight of phosphatidyl choline (PC).
5. The process as claimed in any one of the previous claims, wherein the final extract comprises at least 25 % by weight of phosphatidyl choline (PC), and more than 50 % by weight of Aceton Insolubles (AI).
6. The process as claimed in any one of the previous claims, wherein the aliphatic alcohol is ethanol.
7. The process as claimed in any one of the previous claims, wherein the water concentration in the aliphatic alcohol is in the range of from 0 to 10% by weight.
8. The process as claimed in any one of the previous claims, wherein steps (a) and (b) are executed at least in part in a multistage extraction apparatus comprising for each stage: i) a rotor, ii) a mixing chamber connected to the rotor, and wherein the two liquid streams are mixed, and wherein the mixing chamber comprises iia) a stationary agitator placed in the mixing chamber, and iib) a settling chamber in which the liquid streams are separated by the centrifugal force generated by the mixing chamber.
9. The process as claimed in claim 8, wherein the stationary agitator comprises a stationary disc, and wherein the mixing is achieved through the speed differential between the stationary disc and the rotating mixing chamber.
10. The process as claimed in any one of the previous claims, comprising at least two extraction and separation stages, wherein the respective extractant is added to the respective raffinate at one or more stages in a counter-current or co-current manner.
11. The process as claimed in any one of the previous claims, wherein the extraction ratio is in the range of from 1 to 5, wherein the extractant phase comprises water in an amount of from 1 to 10 % by weight, wherein the extractant phase has a temperature of from 25 °C to 70 °C, and wherein from 2 to 10 extraction stages are employed using of from 2 to 20.000 g for the separation step.
12. The process as claimed in any one of the previous claims, wherein the phospholipidcontaining feed comprises lecithin.
13. The process as claimed in claim 12, wherein the lecithin is selected from soybean lecithin, corn lecithin, rapeseed lecithin, rice oil lecithin, sunflower lecithin, cotton seed lecithin, palm oil lecithin, marine oil lecithin, biomass lecithin, peanut lecithin, egg yolk lecithin, milk lecithin and/or brain lecithin, more preferably soybean lecithin or sunflower lecithin.
14. The process as claimed in any one of the previous claim, further comprising isolating at least part of the phospholipids from the raffinate and/or extract phase.
15. A phospholipid-depleted raffinate obtainable according to the process as claimed in any one of the previous claims wherein said raffinate has an Acetone Insoluble (AI) content of between 55 and 75 wt%.