The invention relates to lipid compounds derived from alkoxyglycerols (or lipid ethers) with a beneficial activity for health, or which can be lipid carriers for administering bioactive ingredients. The invention further relates to the process of obtaining said modified alkoxyglycerols by means of extraction with supercritical fluids and subsequent enzymatic or chemical interesterification.
1. Modified alkoxyglycerols of general formula CH<2>OR<1>-CHOR<2>-CH<2>OR<3>where R<1>, R<2>and R<3>independently represent between a hydrogen group; a saturated or unsaturated, linear or branched C<2>-C<24>alkyl group, with or without double bonds, or a conjugated or unconjugated, saturated or unsaturated, linear or branched C<1>-C<24>acyl group with or without double bonds, characterized in that at least one of R<1>, R<2>or R<3>represents an alkyl group and in that at least one of R<1>, R<2>or R<3>represents a conjugated linoleyl group. 2. Modified alkoxyglycerols according to claim 1, where R<1>is a saturated or unsaturated, linear or branched C<2>-C<24>alkyl; R<2>is a hydrogen, a C<2>-C<24>alkyl group or a C<1>-C<24>acyl group, and R<3>is a hydrogen, a C<2>-C<24>alkyl group or a C<1>-C<24>acyl group, both being conjugated or unconjugated, saturated or unsaturated, linear or branched with or without double bonds, characterized in that at least one of R<2>or R<3>represents an acyl group. 3. Modified alkoxyglycerols according to claim 1, characterized in that at least one of R<1>, R<2>and R<3>represents a saturated acyl group of 1-10 carbons. 4. Modified alkoxyglycerols according to claim 1, characterized in that at least one of R<1>, R<2>and R<3>is an acyl group with one or more unsaturations. 5. Modified alkoxyglycerols according to claim 1, characterized in that at least one of R<1>, R<2>and R<3>represents an oleyl group. 6. Modified alkoxyglycerols according to claim 1, characterized in that at least one of R<1>, R<2>and R<3>represents an acyl group corresponding to that of a long-chain polyunsaturated acid (PUFA) of the omega-3 or omega-6 family. 7. Modified alkoxyglycerols according to claim 1, characterized in that at least one of R<1>, R<2>and R<3>represents an alkyl group with an even number of carbon atoms. 8. Modified alkoxyglycerols according to claim 1 for their use in preventing cardiovascular diseases. 9. Modified alkoxyglycerols according to claim 1 for their use as an immune system stimulant. 10. Modified alkoxyglycerols according to claim 1 for their use as an anticarcinogen. 11. A process for preparing modified alkoxyglycerols according to claim 1, characterized in that it comprises: a) supercritical fractionation in countercurrent column of shark liver oil for obtaining a refined product rich in alkoxyglycerols and an extract rich in squalene, b) saponification of the refined product rich in alkoxyglycerols of a) for producing an unsaponifiable fraction rich in non-esterified alkoxyglycerols, and c) chemical or enzymatic re-esterification of the product of b) with conjugated or unconjugated, aliphatic, saturated or unsaturated, linear or branched chain C<2>-C<24>monocarboxylic acids, wherein at least one of them is a conjugated linoleyl group. 12. A process according to claim 11, characterized in that the supercritical fluid used for fractionation is carbon dioxide. 13. A process according to claim 11, characterized in that the extraction pressure in the column is between 90 and 320, preferably 90 and 270 bar, and the extraction temperature is between 10°C and 90°C. 14. A process according to claim 11, characterized in that saponification is carried out with soda, with potash or in a basic medium with an alkali. 15. A process according to claim 11, characterized in that re-esterification is an enzymatic process and is carried out with lipase. 16. A process according to claim 11, characterized in that a C<2>-C<24>monocarboxylic acid used in re-esterification is eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid, oleic acid, eicosaenoic acid, docosaenoic acid or mixtures thereof. 17. The use of modified alkoxyglycerols according to any of claims 1-7 for the manufacture of food or pharmaceutical compositions to prevent cardiovascular diseases. 18. The use of modified alkoxyglycerols according to any of claims 1-7 for the manufacture of food or pharmaceutical compositions to stimulate the immune system. 19. The use of modified alkoxyglycerols according to any of claims 1-7 for the manufacture of food or pharmaceutical compositions with anticarcinogenic activity. 20. The use of modified alkoxyglycerols according to claims 1-7 as carrier agents of other or others bioactive compounds in food or pharmaceutical compositions. 21. The use according to claim 20 where bioactive compounds synergistically act with the alkoxyglycerols simultaneously acting as carrier agents. 22. The use according to claim 21 where the bioactive compounds are fatty acids of the omega-3 and/or CLA family.