Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B1/00—Production of fats or fatty oils from raw materials
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B1/00—Production of fats or fatty oils from raw materials
  • C11B1/10—Production of fats or fatty oils from raw materials by extracting
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/006—Refining fats or fatty oils by extraction
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B7/00—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils
  • C11B7/0008—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils by differences of solubilities, e.g. by extraction, by separation from a solution by means of anti-solvents
  • C11B7/0025—Separation of mixtures of fats or fatty oils into their constituents, e.g. saturated oils from unsaturated oils by differences of solubilities, e.g. by extraction, by separation from a solution by means of anti-solvents in solvents containing oxygen in their molecule
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
  • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs

Definitions

• the present invention is directed to the extraction and purification of lipids, and in particular, lipids containing long chain polyunsaturated fatty acids (LCPUFAs). i particular, processes are provided for obtaining high concentrations of desired LCPUFAs and low concentrations of undesired compounds such as trisaturated glycerides.
• LCPUFAs long chain polyunsaturated fatty acids
• winterization is the name given to the process of removing sediment that appears in vegetable oils at low temperature. It originated from the early practice of allowing cottonseed oil to remain in outdoor storage during the cool winter months and filtering off the sediment-free oil. Dry fractional crystallization is a process wherein triglycerides with the highest melting temperature preferentially crystallize during cooling from a neat liquid (e.g., liquid lipid). After crystallization is complete, the solid phase is separated from the liquid phase by one of several types of physical processes. Alternatively, solvent crystallization is used to promote triglyceride crystal formation, because triglycerides at low temperature generally form more stable crystals with solvent than without solvent.
• Docosahexaenoic acid (DHA)-rich lipid was extracted using conventional techniques and solvents (e.g., hexane) from Schizochytrium sp. biomass produced by fermentation, and the resulting extracted lipid was winterized by chilling it to -2 to 2°C followed by centrifugation. The lipid was then refined, bleached and deodorized, and put into gelatin capsules for sale as nutritional supplements. A problem arose with this product in that a haze would form in the product over time.
• solvents e.g., hexane
• dried microalgae are suspended in commercial-grade n-hexane and wet milled.
• Hexane primarily extracts triglycerides, diglycerides, monoglycerides and esterified sterols, although other components of the total lipid fraction, such as phospholipids, free sterols and carotenoids, can also be extracted to a lesser degree.
• Centrifugation is employed to separate spent biomass from a lipid-rich miscella.
• the resultant mixture of lipid and solvent is referred to as miscella.
• the lipid content of the clarified miscella is adjusted to about 45 wt% using n-hexane.
• the miscella is winterized, in particular, the miscella is chilled to approximately -1°C, and held for 8 to 12 hours, to crystallize any saturated fats, or high melting point components.
• the miscella is then filtered to remove the crystallized stearine phase. Hexane is removed from the miscella, leaving behind the winterized lipid.
• the winterized lipid is heated and treated with citric acid or phosphoric acid to hydrate any phosphatides present in the lipid.
• Sodium hydroxide is added to neutralize any free fatty acids present.
• the resulting gums (hydrated phosphatides) and soapstock (neutralized fatty acids) are removed using a centrifuge.
• the lipid is mixed with water and re-centrifuged to remove any residual gum/soapstock. This step can be carried out with the first centrifugation.
• the refined lipid is bleached with silica and bleaching clay following pre-treatment with citric acid, to remove peroxides, color compounds, and traces of soapstock, phospholipids and metals. Filter aid is added at the end of the cycle to facilitate removal of the spent bleaching compounds from the lipid via filtration.
• An additional step can be performed, where the bleached lipid is chilled to from about 5°C to about 15°C and held for about 6 to about 8 hours to crystallize any remaining stearines or waxes, if it is apparent that a sediment layer will form upon standing.
• Filter aid can be used to facilitate removal of the crystals via filtration, if this step is performed.
• a deodorizer operated at elevated temperatures under high vacuum, is used to destroy peroxides, which if left intact could later decompose and initiate free radical reactions. This step also removes any remaining low molecular weight compounds that can cause off-odors and flavors. Contact times in the deodorizer are minimized to prevent the formation of trans-fatty acids. Safe and suitable food approved antioxidants are added. The stabilized lipid is packaged in a phenolic-lined metal container under a nitrogen atmosphere to prevent oxidation.
• the haze that fonned in the lipid-filled gelatin capsules was analyzed and found to be composed of crystals of triglycerides containing myristic (14:0) and palmitic (16:0) fatty acids, a trisaturated fatty acid glyceride. These crystals had a melting point of about 50-55°C.
• the trisaturated glycerides comprised 6-8% of the crude extracted lipid.
• the above-described winterization process lowered the concentration of these trisaturated glycerides to ⁇ 1%; however, not low enough to completely eliminate haze formation in the lipid.
• the present invention includes a process for purifying a lipid composition having predominantly neutral lipid components wherein the composition contains at least one long chain polyunsaturated fatty acid (LCPUFA) and at least one other compound.
• the process includes contacting the lipid composition with a polar solvent and the solvent is selected such that the other compound is less soluble in the solvent than is the LCPUFA.
• the polar solvent can be selected from acetone, isopropyl alcohol, methanol, ethanol, ethyl acetate and mixtures thereof.
• the process further includes maintaining the lipid composition at a temperature range effective to precipitate at least a portion of the other compound.
• the temperature range can be from about -20°C to about 50°C, from about -5°C to about 20°C, from about -5°C to about 5°C or about 0°C.
• the process then includes removing at least a portion of the other compound from the lipid composition to form a lipid product.
• the process can be specifically for the reduction of the formation of haze in a lipid composition in which the compound being removed is a haze-forming compound.
• the lipid composition can include at least 50% or 85% neutral lipid, or at least 50% triglyceride.
• concentration of LCPUFA, on a weight percentage basis can be greater after the process than before, and the concentration of the other compound, on a weight percentage basis, can be less after the process than before.
• the total concentration of any phosphorus-containing compounds present in the lipid, on a weight percentage basis is less after the process than before.
• the process of the present invention can result in an acceptable product with less downstream processing required, such as with reduced degumming or no degumming required.
• the LCPUFA can be arachidonic acid (ARA), omega-6 docosapentaenoic acid
• DPA(n-6) omega-3 docosapentaenoic acid (DPA(n-3)), eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA).
• the other compound can be trisaturated glycerides, phosphorus-containing materials, wax esters, saturated fatty acid containing sterol esters, sterols, squalene, and/or hydrocarbons.
• the other compound can be trisaturated glycerides, phosphatides and wax esters.
• the other compound can be trisaturated glycerides of lauric (C12:0), myristic (C14:0), palmitic (C16:0) and stearic (C18:0) fatty acids and/or mixtures thereof.
• the lipid composition initially comprises at least one LCPUFA and at least one trisaturated glyceride.
• the LCPUFA can be obtained from a LCPUFA-containing biomaterial selected from LCPUFA-containing microbiai biomass and oilseeds from plants that have been genetically modified to produce LCPUFA-containing lipid.
• the LCPUFA can be obtained from plants that have been modified with LCPUFA-producing genes from microbes.
• the LCPUFA can be obtained from a source selected from the group consisting of thraustochytrid biomass, dinoflagellate biomass, Mortierella biomass, and oilseeds from genetically modified plants containing genes from thraustochytrids, dinoflagellates or Mortierella.
• the LCPUFA is obtained from the group comprising Schizochytrium, Thraustochytrium or Crypthecodinium cohnii biomass or oilseeds from genetically modified plants containing genes from Schizochytrium or Thraustochytrium.
• the solvent: lipid composition ratio is from about 1:10 to about 20:1, from about 1:8 to about 10:1, from about 1:5 to about 5:1, from about 1:2 to about 2.5:1, or about 1:1.
• the time of contact between the solvent and the lipid composition is from about 0.5 to about 12 hours, from about 2 to about 6 hours, or about 4 hours.
• lipid is extracted using the polar solvent at low temperatures such that triglyceride molecules containing the LCPUFA are selectively extracted and other compounds that are not soluble in the polar solvent are not extracted.
• the lipid composition is extracted from a biomass and cellular debris and precipitated other compounds are separated from a miscella comprising the LCPUFA and the polar solvent.
• a further embodiment of the invention includes employing the polar solvent to recover lipid in an extraction process conducted at temperatures that solubilize substantially all triglyceride components; forming a miscella comprising a mixture of the lipid composition and the polar solvent; cooling the miscella to selectively precipitate the undesired compounds; and separating the precipitated other compounds from the miscella.
• the lipid composition can be extracted from biomass and cellular debris and precipitated other compounds are separated from a miscella comprising the LCPUFA and the polar solvent.
• Another embodiment of the invention includes employing the polar solvent to recover lipid from a biomass in an extraction process conducted at temperatures that solubilize substantially all triglyceride components, forming a miscella comprising a mixture of the lipid composition, the polar solvent and cellular debris.
• the process further includes separating the cellular debris from the miscella and cooling the miscella to selectively precipitate the undesired compounds. Finally, the precipitated other compounds are separated from the miscella.
• a further embodiment of the invention includes employing a nonpolar solvent to recover lipid in an extraction process conducted at temperatures that solubilize substantially all triglyceride components, forming a miscella comprising a mixture of the lipid composition and the nonpolar solvent.
• the process further includes removing most of the nonpolar solvent from the miscella, adding a polar solvent to the miscella, and cooling the miscella to selectively precipitate the undesired compounds. Finally, the precipitated other compounds are separated from the miscella.
• a still further embodiment of the invention includes employing a nonpolar solvent to recover lipid in an extraction process conducted at temperatures that solubilize substantially all triglyceride components, forming a miscella comprising a mixture of the lipid composition and the nonpolar solvent and winterizing the miscella. Most of the nonpolar solvent is removed from the miscella, and a polar solvent is added to it. The miscella is cooled to selectively precipitate the undesired compounds which are separated from the miscella. When the nonpolar solvent is removed from the miscella, the residual nonpolar solvent after removal is from about 0 to about 4 weight percent or from about 1 to about 4 weight percent.
• the nonpolar solvent can be hexane.
• the step can be a liquid/solid separation technique, such as centrifugation, filtering or combinations thereof.
• Figure 1 is a flow diagram of a prior extraction process.
• Figure 2 is a flow diagram of a prior refining, bleaching and deodorizing process.
• Figure 3 is a flow diagram of a DHA-rich lipid extraction process of the present invention using acetone in one step.
• Figure 4 is a flow diagram of a DHA-rich lipid extraction process of the present invention using acetone in two steps.
• Figure 5 is a flow diagram of a DHA-rich lipid hexane extraction process and acetone winterization process of the present invention.
• LCPUFAs are fatty acids with 20 or more carbon atoms and two (preferably three) or more double bonds.
• the LCPUFAs can be in a variety of forms, such as phospholipids, free fatty acids and esters of fatty acids, including triglycerides of fatty acids. It will be appreciated that when referring to the desired LCPUFA, what is meant is the LCPUFA in the form that exists in the lipid, most typically a triglyceride, and to a lesser extent mono- and diglycerides.
• the concentration of the desired LCPUFA is higher in the resulting lipid product than it is in the starting lipid composition.
• the undesired components are preferably trisaturated glycerides, such as trisaturated glycerides of lauric (C12:0), myristic (C14:0), palmitic (C16:0) and stearic (C18:0) fatty acids and mixtures thereof.
• Examples of other undesired components include phosphorus-containing compounds (e.g., phosphatides or phospholipids), wax esters, saturated fatty acid containing sterol esters, sterols, squalene, hydrocarbons and the like.
• phosphorus-containing compounds e.g., phosphatides or phospholipids
• wax esters e.g., wax esters
• saturated fatty acid containing sterol esters e.g., sterol esters
• sterols e.g., sterols, squalene, hydrocarbons and the like.
• two or more of the undesired compounds are reduced in the resulting product as compared to the starting lipid, as measured on a weight percent basis.
• amounts will generally be on a weight percent basis, unless indicated otherwise.
• the resulting product is subject to less haze or cloudiness when compared to the starting lipid.
• subsequent processing steps such as refining
• subsequent processing steps such as bleaching and/or deodorizing can help reduce or eliminate the refining (or degumming) step.
• An example of the refining, bleaching and deodorizing process is set forth in comparative Example 2. If the refining process is not eliminated, it can be reduced by reducing the amount of caustic employed. While not wishing to bound by any theory, it is believed that a primary cause of haze or cloudiness results from trisaturated triglycerides. It does not appear to be as important to reduce the mono- and di- substituted triglycerides.
• lipids will refer generally to a variety of lipids, such as phospholipids; free fatty acids; esters of fatty acids, including triglycerides of fatty acids; sterols; pigments (e.g., carotenoids and oxycarotenoids) and other lipids, and lipid associated compounds such as phytosterols, ergothionine, lipoic acid and antioxidants including beta-carotene, tocotrienols, and tocopherol.
• lipids such as phospholipids; free fatty acids; esters of fatty acids, including triglycerides of fatty acids; sterols; pigments (e.g., carotenoids and oxycarotenoids) and other lipids, and lipid associated compounds such as phytosterols, ergothionine, lipoic acid and antioxidants including beta-carotene, tocotrienols, and tocopherol.
• Preferred lipids and lipid associated compounds include, but are not limited to, cholesterol, phytosterols, desmosterol, tocotrienols, tocopherols, ubiquinones, carotenoids and xanthophylls such as beta-carotene, lutein, lycopene, astaxanthin, zeaxanthin, canthaxanthin, and fatty acids such as conjugated linoleic acids, and omega-3 and omega-6 highly unsaturated fatty acids such as eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid, arachidonic acid, stearidonic acid, dihomogammalinolenic acid and gamma-linolenic acid or mixtures thereof.
• lipid refers to lipid and/or lipid-associated compounds.
• desired LCPUFAs such as arachidonic acid (ARA), omega-6 docosapentaenoic acid (DPA(n-6)), omega-3 docosapentaenoic acid (DPA(n-3)), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), are soluble in cold acetone or in an analogous solvent.
• ARA arachidonic acid
• DPA(n-6) omega-6 docosapentaenoic acid
• DPA(n-3) omega-3 docosapentaenoic acid
• EPA eicosapentaenoic acid
• DHA docosahexaenoic acid
• the key characteristic of the solvent is that the desirable LCPUFAs are soluble in the solvent at the desired temperatures, and the undesirable compounds are not soluble in the solvent at the same temperatures.
• a useful guide is to select solvents that have dielectric constants close to those of acetone or ethyl acetate.
• Preferred solvents for use in connection with the present invention include acetone and analogous polar solvents such as isopropyl alcohol, methanol, ethanol, ethyl acetate or mixtures of these solvents.
• the solvents are all polar, and the LCPUFAs, with their double bonds and long carbon chains, are also polar and therefore soluble in the polar solvents. However, if the solvents are too polar, the LCPUFAs may not dissolve.
• the solvent is also preferably useful in food applications.
• acetone can be used to selectively precipitate the trisaturated glycerides from the crude lipid.
• an unwinterized lot of DHA-rich lipid from Schizochytrium sp. was treated with 5 volumes of acetone and chilled, essentially all of the trisaturated glycerides were removed by crystallization followed by centrifugation. This process removed little or none of the DHA-containing triglycerides.
• the resulting winterized lipid contained 41% DHA as compared to 37% by the standard winterization process.
• the embodiment of the process of the present invention i.e., hexane extraction followed by acetone winterization
• about 40% or more reduction in yield loss is realized. This is a significant improvement over the prior process (hexane extraction and winterization plus full refining, bleaching and deodorizing (RBD)).
• RBD bleaching and deodorizing
• lipid is extracted using acetone or analogous polar solvent (instead of hexane) at low temperatures such that triglyceride molecules containing LCPUFA are selectively extracted from Schizochytrium sp. biomass.
• acetone or analogous polar solvent instead of hexane
• a flow diagram of such a process is illustrated in Figure 3. Due to the selectivity of acetone at low temperature (trisaturated glycerides are not soluble in cold acetone, while LCPUFA- containing triglycerides are soluble in cold acetone), it is feasible to selectively remove the LCPUFA-containing triglyceride from biomass and thus eliminate the need for a separate winterization step.
• the solvent extraction can be conducted in any suitable manner.
• the dry biomass can be subjected to mechanical (e.g., in a mill or homogenizer) or chemical (e.g., using an acid, enzyme or base) lysing in the presence of a cold solvent.
• mechanical e.g., in a mill or homogenizer
• chemical e.g., using an acid, enzyme or base
• the cellular debris and precipitated trisaturated glycerides are separated from the miscella in one step.
• Post processing steps such as purification by refining, bleaching and deodorizing, can be performed, if desired.
• a second option is to utilize acetone or analogous polar solvent to quantitatively recover lipid from biomass in a conventional extraction process (including any type of solvent grinding technique). This extraction is conducted at temperatures that solubilize all triglyceride components. Prior to removing cellular debris from the miscella (lipid containing triglycerides in solvent), the miscella is chilled to selectively remove the trisaturated glycerides. The chilled miscella is then centrifuged, filtered, or separated using other techniques to remove both the cellular debris and trisaturated glyceride component. This option combines the concept of extraction and winterization into one step.
• a third option is to utilize acetone or analogous polar solvent to quantitatively recover lipid from biomass in a conventional extraction process (including any type of solvent grinding technique). This extraction is conducted at temperatures that solubilize all triglyceride components. The cellular debris from the miscella (lipid containing triglycerides in solvent) is removed using conventional separation techniques. The miscella is then chilled to crystallize the trisaturated glycerides, which are removed by centrifugation, filtration, or separation using other techniques.
• This option utilizes extraction and winterization in two stages; however, acetone or an analogous polar solvent is utilized to accomplish both tasks. A flow diagram illustrating such a process is shown in Figure 4.
• a fourth option is to utilize a nonpolar solvent such as hexane (e.g., n-hexane, isohexane or a combination thereof) as an extraction solvent and utilize acetone as a winterization solvent.
• a nonpolar solvent such as hexane (e.g., n-hexane, isohexane or a combination thereof)
• acetone as a winterization solvent.
• at least 95%, more preferably at least 96%, more preferably at least 97%, more preferably at least 98% and more preferably at least 99% of the nonpolar solvent is removed prior to winterization.
• the winterization step can be employed at any stage prior to deodorization. A flow diagram illustrating such a process is shown in Figure 5.
• a fifth option is to utilize conventional hexane extraction and hexane-based winterization to remove the majority of the trisaturated glyceride component and employ a "polishing" step prior to deodorization to remove the small amounts of trisaturated glycerides contributing to the haze formation in the lipid.
• the polishing step employs acetone and/or an analogous solvent. This option removes the problems caused by haze, but the lipid level is also reduced.
• the lipid composition initially comprises at least one LCPUFA and at least one trisaturated glyceride.
• the other or undesired compound results in the formation of haze when present in the initial concentration in the initial lipid composition.
• the LCPUFA-containing biomaterial for lipid extraction is selected from the group including: LCPUFA-containing microbiai biomass or oilseeds from plants that have been genetically modified to produce LCPUFA containing lipids, particularly plants that have been modified with the LCPUFA-producing genes from microbes (algae, fungi, protists, or bacteria).
• the LCPUFA-containing biomaterial for lipid extraction is selected from the group including thraustochytrid biomass, dinoflagellate biomass and/or Mortierella biomass, and/or oilseeds from genetically modified plants containing genes from thraustochytrids, dinoflagellate and/or Mortierella.
• the LCPUFA-containing biomaterial for lipid extraction is selected from the group including Schizochytrium, Thraustochytrium and/or Crypthecodinium (preferably, Ci ⁇ pthecodinium cohnii) biomass or oilseeds from genetically modified plants containing genes from Schizochytrium or Thraustochytrium and/or Crypthecodinium (preferably, Crypthecodinium cohnii).
• the initial lipid composition is predominantly made up of neutral lipids.
• the initial lipid composition comprises at least 50% neutral lipids, preferably, at least 60% neutral lipids, preferably, at least 75% neutral lipids, preferably at least 85% neutral lipids and preferably at least 90% neutral lipids.
• the neutral lipid predominantly comprises triglyceride.
• the initial lipid composition comprises at least 50% triglyceride, preferably, at least 60% triglyceride, preferably, at least 75% triglyceride and preferably at least 85% triglyceride.
• the concentration of the desired LCPUFA is greater in the resulting product than in the initial lipid composition.
• Preferred polar solven lipid ratios, based on weight, for the extraction or winterization process are from about 1:10 to about 20:1; more preferably from about 1:8 to about 10:1, preferably from about 1:5 to about 5:1, and preferably from about 1:2 to about 2.5: 1.
• the contact time between the polar solvent and lipid is from about 0.5 to about 12 hours, preferably from about 2 to about 6 hours, and preferably about 4 hours.
• the residual nonpolar lipid is from about 0 to about 4 weight percent, and preferably from about 1 to about 4 weight percent.
• the temperature for the: (i) cold extraction process, (ii) extraction followed by chilling and filtration/centrifugation, (iii) extraction, filtration/centrifugation of cellular debris, followed by chilling and filtration/centrifugation; and (iv) chilling conditions for solvent winterization or polishing steps is from the solidification point of the lipid to the melting point of the undesirable component (e.g. trisaturated glycerides), more preferably from about -20°C to about 50°C, more preferably from about -5 °C to about 20 °C, more preferably from about -5°C to about 5°C, more preferably about 0 °C.
• the undesirable component e.g. trisaturated glycerides
• LCPUFA-containing triglycerides are preferred attributes of the process.
• Other preferred attributes of the process include the selective recovery of only LCPUFA-containing triglycerides at the expense of trisaturated glycerides and other components that are relatively insoluble in cold acetone including phosphatides, wax esters, saturated fatty acid containing sterol esters, sterols, squalene, hydrocarbons and the like.
• By selectively recovering only the LCPUFA-containing triglyceride at the expense of these undesirable components allow the possibility of eliminating or reducing additional downstream purification steps (such as winterization, refining, and bleaching).
• sample 1 A sample of DHA-rich lipid obtained from Schizochytrium (Sample 1, unwinterized lipid, a.k.a. "high melt") and an isolated sediment from another DHA-rich lipid obtained from Schizochytrium (Sample 2) were analyzed to detennine the nature of the solid phase (Sample 1) and the floc/sediment (Sample 2).
• Unwinterized lipid Sample 1 produced at plant scale (a semi-solid at ambient temperature) was dissolved in 4 volumes of cold acetone and mixed. A solid white powder (approximately 7% by weight) was isolated by filtration through a glass fiber filter.
• the solid white powder had a melting temperature of 52.4-53.5°C, was shown to be triglycerides (based on a single spot by thin layer chromatography (TLC)), and contained predominantly myristic (26%) and palmitic acids (66%) when analyzed by GLC.
• This high melting triglyceride fraction contains saturated fatty acids with very little DHA/DPA.
• the isolated lipid fraction (91% by weight) was an orange-colored liquid at room temperature and contained 41.0% DHA and 16.0% DPA. DHA and DPA were enriched by approximately 8% compared to the starting fatty acid profile of Sample 1 — this is a true "purification" of DHA and DPA.
• DHA-rich reprocessed lipid from Schizochytrium contained an obvious floe-like material (haze) when stored for a period of days at ambient temperature.
• the floe was isolated by centrifugation.
• the floc/sediment (“Sample 2 sediment”) was dissolved in 10 volumes of cold acetone, mixed and filtered.
• Approximately 15% by weight of a solid white powder was isolated by filtration through a glass fiber filter.
• the solid white powder had a melting temperature of 50.1-51.4°C and was shown to be triglycerides (based on single spot by TLC) containing predominantly myristic (29%) and palmitic acids (59%). This is a high melting triglyceride fraction containing saturated fatty acids with little DHA/DPA.
• the isolated lipid fraction (85% by weight) was a clear, orange-colored liquid at room temperature and contained 41.1% DHA and 16.3% DPA.
• the floe formation in reprocessed lipid from Schizochytrium is believed to result from a high melting triglyceride, containing myristic and palmitic fatty acids, which crystallizes from lipid upon standing.
• Sample 1 (250g bottle) was pulled from frozen storage. This is a sample of unwinterized lipid. The sample was allowed to warm to ambient temperature and used as is. Sediment (Sample 2) was isolated from DHA-rich lipid using a lab centrifuge.
• the DHA-rich lipid was a reprocessed lot of lipid that contained a visible floe when left to stand at ambient temperature.
• the floe was isolated by centrifuging the sample and decanting the liquid fraction from the sediment.
• the liquid fraction remained clear at ambient temperature; therefore the floe was believed to be present in the isolated sediment.
• Acetone Winterization - Unwinterized lipid (Sample 1) and sediment isolated from reprocessed lipid (Sample 2) were fractionated using an acetone winterization procedure.
• the sediment and unwinterized sample were dissolved in excess cold acetone (ice/water bath temperature) and mixed to dissolve and suspend lipid components.
• the solution/suspension was immediately filtered through a glass fiber filter under vacuum.
• the filter paper and the contents remaining on the paper were washed with small amounts of cold acetone.
• the contents of the filter paper were air dried and weighed.
• the lipid/acetone fraction was concentrated under vacuum to afford neat lipid and weighed.
• TLC - TLC was performed to determine lipid class composition using silica gel 60 plates.
• the developing solvent system consisted of a 90:10:1 mixture of petroleum ether: ethyl ether: acetic acid.
• the R f of the spots were compared to those listed in
• Sample 2 (reprocessed) along with acetone winterization fractions were transesterified using anhydrous HCl in methanol following procedures for determining the free fatty acid profile, from C12 to C22:6. All FAME preparation and GLC work were completed. FAME's were identified and quantified using NuChek Prep analytical reference standard 502 using an internal standard (C19:0) to determine empirical response factors.
• Gas-liquid chromatography Gas-liquid chromatography of methyl esters was performed using a Hewlett-Packard Model 6890 Series II gas-liquid chromatograph equipped with a Hewlett-Packard autosampler, ChemStation software, a 30 m x 0.32mm SP-2380 capillary column (Supelco), and a flame-ionization detector.
• the oven temperature was held at 120°C for 3 min, programmed to 190°C at 5°C/min, held at 190°C for 1 min, programmed to 260°C at 20°C/min, and then held for 3 minutes at 260°C.
• the injector temperature was set at 295°C and the detector temperature was set at 280°C.
• Helium was used as a carrier gas and a split injection technique was employed.
• the lipid/acetone fraction resulting from filtration was concentrated by rotary evaporation to afford 13.13 g of an orange-colored liquid material (liquid at ambient temperature). This resulted in a 91% overall recovery; therefore approximately 2% of material was lost at bench scale.
• the solid white fraction and the lipid fraction isolated after "acetone winterization" were analyzed by TLC to determine lipid composition.
• the solid white fraction was shown to be triglycerides based on TLC (one spot with an Rf corresponding to a triglyceride was observed). Many spots were observed by TLC upon spotting and developing the lipid fraction. The Rf of the spots was consistent with lipid components comprising squalene, steryl esters, triglycerides, and sterols (all tentative assignments). No further analysis of lipid class composition was performed.
• the solid white fraction isolated after acetone winterization had a melting point range of 52.4-53.5°C.
• the solid and liquid fraction isolated after acetone winterization were transesterified to methyl esters and the methyl esters were analyzed by gas-liquid chromatography.
• the complete profile of FAME'S for both the solid and liquid fraction isolated by acetone winterization along with unwinterized DHA-rich fat (Sample 1) is shown in Table 1. As is evident, the solid fraction contained very little DHA (2.4%) and DPA (0.9%) with methyl myristate (26%) and methyl palmitate (66%) as the predominant fatty acids.
• the liquid fraction isolated after acetone winterization contained myristate (8.3%), palmitate (23.1%), DPA (16.0%), DHA (41.0%) along with other minor fatty acids.
• This profile is compared to that of the starting unwinterized lipid, an enrichment of the DHA of approximately 8% is seen, consistent with the removal of the predominantly trisaturated glyceride component. This represents a purification step.
• the lipid/acetone fraction resulting from filtration was concentrated by rotary evaporation to afford 0.94 g of an orange-colored liquid material (liquid at ambient temperature). This resulted in an 85% overall recovery.
• the solid white fraction and the lipid fraction isolated after acetone fractionation were analyzed by TLC to determine lipid composition.
• the solid white fraction was shown to be triglycerides based on TLC (one spot with an R f corresponding to a triglyceride was observed). Many spots were observed by TLC upon spotting and developing the lipid fraction. The R f of the spots was consistent with lipid components comprising squalene, steryl esters, triglycerides, and sterols (all tentative assignments). No further analysis of lipid class composition was performed.
• the solid white fraction isolated after acetone winterization had a melting point range of 50.1-51.4°C.
• the solid and liquid fraction isolated after acetone winterization were transesterified to methyl esters and the methyl esters were analyzed by gas-liquid chromatography.
• the complete profile of FAME'S for both the solid and liquid fraction isolated by acetone winterization along with Sample 2 sediment is shown in Table 1.
• the solid fraction contains very little DHA (6.4%) and DPA (2.6%) with methyl myristate (29%) and methyl palmitate (59%) as the predominant fatty acids.
• the liquid fraction isolated after acetone winterization contains myristate (8.4%), palmitate (23.2%), DPA (16.3%), DHA (41.1%) along with other minor fatty acids.
• Comparative Example Table 2 set forth below, represents a comparative prior method as shown in Comparative Figure 1 followed by Comparative Figure 2.
• Table 3 set forth below, represents a process of the present invention, as set forth in Figure 5 followed by the bleaching, deodorizing and refining of Comparative Figure 2.
• a crude extract of Schizochytrium oil was subjected to a variety of winterization procedures in which a lipid composition was extracted from biomass with hexane. The hexane was removed to produce a crude extracted oil having a residual amount of hexane. The extracted oil was then extracted with acetone at a particular acetone/oil ratio and winterized at a particular temperature for a given amount of time. The % residual hexane, acetone/oil ratio, winterization temperature and winterization time were varied in different experiments. The processes were evaluated in terms of filtration time, oil recovery and haziness after two weeks. The details of the experiments and the results are shown below in Table 4.
• Typical recovery in plant is around 70-75%.
• the floe is triglycerides containing predominantly myristic and palmitic acids. This is based on TLC, IR, and resulting FAME analysis by GLC.
• the triglycerides comprising the floe had a high melting temperature (50.1-51.4°C).
• the isolated liquid fraction following acetone winterization contained 41.0% DHA (expressed as a percentage of total fatty acid methyl esters) compared to 37.7% DHA in the starting unwinterized lipid. This is an approximate 8% enrichment of DHA, consistent with the removal of 7% trisaturated fatty acid glycerides.
• the solid material is mainly trisaturated fatty acid glyceride (>94% saturated fatty acids) with very little DHA (2.4%).
• Solvent assisted winterization can be used to achieve DHA purification.

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