DHA ENRICHED POLYUNSATURATED FATTY ACID COMPOSITIONS

Abstract

There is provided a vegetable-based lipid composition comprising DHA, ALA, and oleic acid (typically as a fatty acid ester) in particular proportions. The composition also contains low levels of EPA and palmitic acid. The composition is obtainable from a single source by conventional processing methods, and has improved stability properties.

Claims

1. A vegetable-based lipid composition comprising: (i) docosahexaenoic acid (22:6n-3) in an amount of from about 15% to about 35% by weight of the total fatty acid content of the composition; (ii) eicosapentaenoic acid (20:5n-3) in an amount of up to about 5% by weight of the total fatty acid content of the composition; (iii) α-linolenic acid (18:3n-3) in an amount of from about 10% to about 20% by weight of the total fatty acid content of the composition; (iv) oleic acid (18:1 n-9) in an amount of from about 20% to about 40% by weight of the total fatty acid content of the composition; and (v) palmitic acid in an amount of up to about 1.5% by weight of the total fatty acid content of the composition; wherein components (i) to (v) are each independently provided in the form of a fatty acid, a fatty acid salt, a fatty acid ester or a salt of a fatty acid ester.

2. The lipid composition of claim 1, wherein docosahexaenoic acid (22:6n-3) is present in an amount of from about 20% to about 35% by weight of the total fatty acid content of the composition.

3. The lipid composition of claim 1, wherein the eicosapentaenoic acid is present in an amount of up to about 3% by weight of the total fatty acid content of the composition.

4. The lipid composition of claim 1, wherein the α-linolenic acid is present in an amount of from about 12% to about 20% by weight of the total fatty acid content of the composition.

5. The lipid composition of claim 1, wherein the oleic acid is present in an amount of from about 20% to about 35% by weight of the total fatty acid content of the composition.

6. The lipid composition of claim 5, wherein the palmitic acid (16:0) is present in an amount of up to about 1.0% by weight of the total fatty acid content of the composition.

7. The lipid composition of claim 1, wherein components (i) to (v) are each independently provided in the form of a fatty acid ester or a salt of a fatty acid ester.

8. The lipid composition of claim 7, wherein components (i) to (v) are each independently provided in the form of a fatty acid ethyl ester or part of a triglyceride.

9. The lipid composition of claim 1, wherein the lipid composition is derived from a single source.

10. The lipid composition of claim 1, wherein the lipid composition is derived from a plant.

11. The lipid composition of claim 10, wherein the plant is an oilseed selected from Brassica sp., Gossypium hirsutum, Linum usitatissimum, Helianthus sp., Carthamus tinctorius, Glycine max, Zea mays, Arabidopsis thaliana, Sorghum bicolor, Sorghum vulgare, Avena sativa, Trifolium sp., Elaesis guineenis, Nicotiana benthamiana, Hordeum vulgare, Lupinus angustifolius, Oryza sativa, Oryza glaberrima, Camelina sativa, or Crambe abyssinica.

12. The lipid composition of claim 1, wherein the composition is provided in the form of a tablet, capsule, encapsulated gel, ingestible liquid or powder, or a topical ointment or cream.

13. The lipid composition of claim 1, further comprising one or more additional components selected from the group consisting of an antioxidant, a stabiliser and a surfactant.

14. The lipid composition of claim 1, for use in the treatment or prevention of cardiovascular disease, protection against death in patients with cardiovascular disease, reduction of overall serum cholesterol levels, reduction in high BP, increase in HDL:LDL ratio, reduction of triglycerides, or reduction of apolipoprotein-B levels.

15. A method for producing the lipid composition as of claim 1, comprising: (a) providing a mixture of fatty acid ethyl esters; (b) subjecting that mixture to a first molecular distillation step to obtain a first residue; and (c) subjecting the first residue to a second molecular distillation step.

Description

[0094] The invention is illustrated by the following examples in which:

[0095] FIG. 1 shows propanal release data for the canola oil and reference oil (following transesterification and distillation), demonstrating the improved stability of the canola oil described herein; and

[0096] FIG. 2 shows propanal release data for the canola oil and reference oil (following RBD refinement, transesterification and distillation), demonstrating the improved stability of the canola oil described herein.

GENERAL METHODS

[0097] GC Sample Preparation and GC Parameters

[0098] Neat fatty acid ethyl esters were diluted to 0.25% (v/v) in 50:50 Chloroform:Methanol and 0.01% BHT. The ethyl ester solutions were diluted to 2.5 mg/mL in Chloroform:Methanol.

[0099] Control checks were prepared as fatty acid methyl esters for canola oil, tuna oil and 3× canola-DHA oil. These were analysed with every batch of samples to check GC performance and to monitor for any DHA degradation due to activity in the GC system.

[0100] The methyl esters were prepared as follows:

[0101] Neat oil was diluted to 0.33% (v/v) in 50:50 Chloroform:Methanol & 0.01% BHT (butylated hydroxytoluene). 50 μL of 0.05N Meth-Prep II solution (0.2N methanolic solution of m-trifluoromethylphenyl trimethylammonium hydroxide) was added, the solution vortexed and allowed to incubate at 40° C. for 30 min. The final solution was equivalent to 0.25% (v/v) of Oil.

[0102] The ethyl ester (samples) and methyl ester (Checks) were run on a Shimadzu GC-2010 Plus, with flame ionisation detector (FID) and split injection using the following parameters:

[0103] Column: 30 m BPX-70, 0.32 mm internal diameter, 0.25 pm film thickness. Injection volume: 0.5 μL

[0104] Results were calculated as area normalised (i.e. area % after fatty acid peaks are identified and non-fatty acid peaks are excluded from the sum of areas of all peaks).

[0105] The identities of the ethyl ester peaks were determined by comparing a fatty acid ethyl ester chromatogram with a fatty acid methyl ester chromatogram. The relative elution order was almost identical, however the ethyl esters eluted later as a group compared with the fatty acid methyl esters. The elution order of the fatty acid methyl esters had been previously identified using reference standards and GC-MS.

EXAMPLES

Example 1—DHA Canola Oil Extraction from Seeds

[0106] Canola of a variety disclosed in US patent publication no. US 2018/0016590 A1 was grown as a summer crop. The seed was harvested and then stored at room temperature prior to crushing.

[0107] 272 kg of the seed was crushed to produce DHA oil using a Kern Kraft KK80 screw press. The expeller collar heater temperature was set to the maximum set temperature on the thermostat. Initial ambient and choke temperature was 20° C. and the choke distance was set at 73.92 mm. The seed was fed with continual oil and meal collection without stopping the expeller till all the seed was crushed.

[0108] The speed of rotation of the auger, the temperature of the meal and expelled oil were monitored throughout the pressing. The crush time was 4 hours for 270 kg which is a throughput rate of 67.5 kg/hr. A yield of 87.2 kg (32%) crude oil was obtained. After filtering to remove fines, the yield was 77.2 kg (28%).

Example 2—Reference Blend Oil

[0109] Pure fish oil contains low levels of ALA fatty acids and significantly higher levels of EPA and DHA. A reference oil blend (referred to herein as the “crude triglyceride reference blend oil” or similar) was designed to be as similar as possible in composition to the filtered DHA Canola oil obtained in Example 1. This was done by (a) matching the total level of DHA to that in the DHA Canola oil and (b) matching the ratio of DHA/(ALA+EPA). This was achieved by blending a fish oil rich in DHA (tuna), an oil rich in ALA (flaxseed oil) and standard Canola oil. The resulting reference blend oil also has a similar total omega-3 content to the DHA Canola oil.

Example 3—Fatty Acid Compositions of the Crude DHA Canola Oil and Reference Blend

[0110] The fatty acid compositions of the filtered crude oil and the reference blend oil were analysed. The results are shown below.

TABLE-US-00001 Crude DHA Crude Reference Fatty Acid Canola oil (wt %) oil (wt %) Palmitic C16:0 4.3 9.6 Stearic C18:0 1.9 3.8 Oleic C18:1n9c 39.4 30.6 Cis-vaccenic C18:1n7c 3.6 2.0 Linoleic C18:2n6c 7.8 11.5 GLA C18:3n6 0.1 0.1 ALA C18:3n3 21.9 21.2 Arachidic C20:0 0.7 0.4 SDA C18:4n3 2.2 0.2 Gondoic C20:1n9c 1.4 0.8 Behenic C22:0 0.3 0.2 ETA C20:4n3 1.0 0.1 Erucic C22:1n9c 0.0 0.1 EPA C20:5n3 0.4 1.7 DPA3 C22:5n3 0.9 0.4 DHA C22:6n3 10.2 9.8 Other 4.0 7.6

Example 4—Oil Stability Assessment

[0111] A Rancimat stability study was performed using the crude DHA canola oil and reference blend described in Examples 1 and 2, respectively. The method involved testing about 2.5 g of test material using the standard procedures for a Metrohm 743 Rancimat at 90° C.

[0112] The table below summarises the results obtained from these oils at 90° C. The experiments were performed in duplicate.

TABLE-US-00002 Oil Time DHA Canola oil 7 hrs 29 min 7 hrs 17 min Reference oil 10 hrs 26 min 10 hrs 11 min

[0113] The DHA canola oil showed consistently poorer stability than the reference oil.

Example 5—Chemical Trans-Esterification of Crude Canola-DHA Oil

[0114] To a dry, nitrogen flushed Buchi CR101 chemreactor fitted with a mechanical stirrer was added absolute ethanol (12.5 L) and the crude triglyceride canola oil (“DHA Canola oil”) obtained in Example 1 (5.00 kg) and the mixture stirred.

[0115] To the above mixture was added sodium ethoxide (150 g) which was rinsed into the reactor with further absolute ethanol (2.5 L) and stirring continued for 16 hr at ambient temperature. A .sup.1H NMR spectrum recorded of a sample taken from the mixture indicated the reaction was complete.

[0116] The trans-esterification procedure was performed on 5.22 kg of crude canola-DHA oil. To the resulting crude reaction mixture was added 40-60° C. boiling point petroleum spirits (pet. spirit, 10 L) and water (10 L) and the mixture carefully acidified to pH 7 with 10% hydrochloric acid (870 mL in total required, Merck Universal Indicator strips, pH 0-14) with thorough mixing.

[0117] The resulting mixture was allowed to stand in the reactor, after which 2 phases formed. The pet. spirit layer was removed and the aqueous layer further extracted with pet. spirit (3×5 L). The combined pet. spirit layers were returned to the reactor and evaporated in vacuo to low volume (approx. 10 L). The resulting concentrated solution was drained from the reactor, dried over anhydrous magnesium sulphate (approx. 1 kg), filtered and concentrated in vacuo to give a yellow oil (5.13 kg).

Example 6—Chemical Trans-Esterification of Crude Reference Blend Oil

[0118] To a dry, nitrogen flushed Buchi CR101 chemreactor fitted with a mechanical stirrer was added absolute ethanol (12.5 L) and the crude triglyceride reference blend oil obtained according to Example 2 (5.00 kg) and the mixture stirred.

[0119] To the above mixture was added sodium ethoxide (150 g) which was rinsed into the reactor with further absolute ethanol (2.5 L) and stirring continued for 16 hr at ambient temperature. A .sup.1H NMR spectrum recorded of a sample indicated little or no reaction had taken place. Further sodium ethoxide (57 g) was added to the mixture and stirring continued.

[0120] After an additional 5 hrs, a .sup.1H NMR spectrum of a sample indicated the reaction was 75% complete. Further sodium ethoxide (60 mL of a 21% solution in ethanol) was added to the mixture and stirring continued for 3 days, after which time the reaction was complete.

[0121] Example Product Isolation from Crude Reference Blend Chemical Trans-Esterification

[0122] The trans-esterification procedure was performed on 5.17 kg of crude reference blend oil. To the resulting crude reaction mixture was added pet. spirit (15 L) and water (3.3 L) and the mixture carefully acidified to pH 7 with 10% hydrochloric acid (910 mL in total required) with thorough mixing.

[0123] The resulting mixture was allowed to stand in the reactor, after which 2 phases formed. The pet. spirit layer was removed and the aqueous layer further extracted with pet. spirit (2×7.5 L). The combined pet. spirit layers were returned to the reactor and evaporated in vacuo to low volume (approx. 10 L). The resulting concentrated solution was drained from the reactor, dried over anhydrous magnesium sulphate (approx. 1 kg), filtered and concentrated in vacuo to give a yellow oil (5.39 kg).

Example 7—Fatty Acid Composition Analysis of the Transesterified Oils

[0124] The fatty acid compositions of the transesterified products obtained in Examples 5 and 6 were analysed. The results are shown below.

TABLE-US-00003 DHA Canola oil Reference oil Fatty Acid (wt %) (Example 5) (wt %) (Example 6) Palmitic C16:0 4.3 9.4 Stearic C18:0 1.9 3.7 Oleic C18:1n9c 39.1 31.2 Cis-vaccenic C18:1n7c 3.6 2.0 Linoleic C18:2n6c 7.8 11.9 GLA C18:3n6 0 0 ALA C18:3n3 22.0 22.3 Arachidic C20:0 0.6 0.4 SDA C18:4n3 2.2 0.2 Gondoic C20:1n9c 1.3 0.7 Behenic C22:0 0.3 0.2 ETA C20:4n3 1.0 0.1 Erucic C22:1n9c 0.0 0.0 EPA C20:5n3 0.4 1.8 DPA3 C22:5n3 0.9 0.4 DHA C22:6n3 10.3 9.7 Other 4.1 5.9

Example 8—Distillation of Transesterified Canola Oils

[0125] Standard Procedure for the Removal of More Volatile Components of Fatty Acid Ethyl Esters (FAEE) Mixtures by Vacuum Distillation

[0126] The crude fatty acid ethyl esters (FAEE) from the crude canola-DHA (obtained in Example 5) were subjected to distillation under the following conditions. Separation by distillation was achieved by passing the trans-esterified crude oil through a Pope 2 inch (50 mm) wiped film still under vacuum equipped with 2×1000 ml collection flasks collecting the distillate and residue. Each was analysed for fatty acid composition.

[0127] Vacuum was supplied by an Edwards 3 rotary pump and the vacuum measured by an ebro vacumeter VM2000.

[0128] The oil was fed into the still by a Cole-Palmer Instrument Company easy-load II peristaltic pump at 4 mL/min with the still motor set to 325 rpm with water condenser used to condense the distillate. The feed was continued until such time as one or other of the receiver flasks was full.

[0129] Crude canola-DHA FAEE was distilled under these conditions with the heater bands initially set to 147° C. The objective was to obtain a 50:50 split of distillate:residue. During the first 30-45 minutes of the experiment, the temperature of the heater bands was increased to 154° C. to increase the proportion of the oil that distilled and the still then allowed to equilibrate. After half an hour, the temperature of the heater bands was adjusted over half an hour down to 149° C. The remainder of the distillation took place at 149° C. The total time of distillation was 350 minutes. A portion of the residue from the above distillation was again subjected to the removal of more volatile components by distillation under the standard conditions with the temperature of the heater bands set to 149° C. The total time of distillation was 95 minutes.

TABLE-US-00004 Distillation Feed Distillate Residue First 1395.4 g 699.5 g 690.5 g Second  376.3 g 211.7 g 160.3 g

Example 9—Distillation of Transesterified Crude Reference Blend-Derived FAEE

[0130] The crude fatty acid ethyl esters (FAEE) from the crude reference blend (obtained in Example 6) were subjected to distillation under the same conditions as shown in the preceding Example.

[0131] Crude reference blend FAEE was distilled under these standard conditions with the heater bands initially set to 152° C. The objective was to obtain a 50:50 split of distillate:residue. After 20 minutes the temperature of the heater bands was set to 154° C. to increase the flow of distillate. After a further hour the heater bands temperature was adjusted to 153° C. and then 152° C. over the next hour. For the last hour of the distillation the heater bands temperature was set to 153° C. The total time of distillation was 380 minutes. The residue from the above distillation was again subjected to the removal of more volatile components by distillation under the standard conditions. The objective was to obtain a 50:50 split of distillate:residue. The distillation was mostly performed with the heater bands set to 150-151° C. The total time of distillation was 195 minutes.

TABLE-US-00005 Distillation Feed Distillate Residue First 1515.7 g 729.6 g 775.1 g Second  768.5 g 399.7 g 363.3 g

Example 10—Fatty Acid Composition Analysis for the Distilled Oils

[0132] The fatty acid compositions of the double-distilled products obtained in Examples 8 and 9 were analysed. The results are shown below.

TABLE-US-00006 DHA Canola oil Reference oil Fatty Acid (wt %) (Example 8) (wt %) (Example 9) Palmitic C16:0 0.7 1.54 Stearic C18:0 1.56 3.30 Oleic C18:1n9c 26.15 22.36 Cis-vaccenic C18:1n7c 2.52 1.49 Linoleic C18:2n6c 5.07 8.23 GLA C18:3n6 0.00 0.00 ALA C18:3n3 15.04 16.28 Arachidic C20:0 1.44 0.88 SDA C18:4n3 1.41 0.12 Gondoic C20:1n9c 2.63 1.50 Behenic C22:0 1.16 0.84 ETA C20:4n3 1.75 0.21 Erucic C22:1n9c 0.00 0.10 EPA C20:5n3 0.75 3.33 DPA3 C22:5n3 2.81 1.18 DHA C22:6n3 30.65 30.53 Other 6.36 8.12

Example 11—Oil Stability Assessment

[0133] Headspace GC-MS Stability Trial

[0134] Headspace analysis was conducted on the enriched products described above to assess the quantities of propanal that are released under specific conditional. Increased levels of propanal release demonstrate reduced stability for the test material.

[0135] SPME (Solid-Phase Microextraction) Method:

[0136] Selected 65 μm PDMS/DVB StableFlex fiber (Supelco fiber kit 57284-u)

[0137] Fibers were conditioned for 10 mins prior to use at 250° C. in a Triplus RSH conditioning station

[0138] Samples were incubated at 40° C. for 1 min prior to extraction.

[0139] Extracted for 1 min from Headspace vial

[0140] Expected to be a good general method capable of capturing a wide range of volatile components.

[0141] GC method:

[0142] Thermo Scientific TRACE 1310 GC

[0143] Thermo Scientific TR-DIOXIN 5 MS column, 0.25 mm internal diameter, 30 m film 0.1 μm

[0144] Split injection 250° C. Split 83, 1.2 ml He/min

[0145] GC Ramp: 40° C. 1 min to 100 at 5° C./min, then to 300° C. at 50° C./min

[0146] A generic MS specific column with good synergy for headspace analysis was used. A slow initial temperature ramp was employed to maximise separation of volatiles before ramping up to maximum to maintain column performance. Split injections were employed to avoid the requirement for cryogenic cooling of the inlet and enhance column resolution.

[0147] Separation of the standards was hampered by some peak overlap but could still be accommodated in the quantitation. 3 standard calibration results (0.1, 0.01 and 0.01%), the molecular ion m/z 56 was employed for detection of propanal. The base peak at m/z 58 is used to detect hexanal.

[0148] MS Method:

[0149] Thermo Scientific DFS high resolution GC-MS

[0150] Low resolution (1000), full scan 35-350 Da at 0.5 s/scan

[0151] Standards:—Propanal and Hexanal standard dilutions were made into DHA Canola Ethyl esters supplied. These Standard mixtures were then added at a volume of 540 μl to 20 ml headspace vials.

[0152] Full scan was employed, allowing the monitoring of all evolved products rather than specific molecules.

[0153] Headspace Stability Results:

[0154] The table below summarises the results obtained from the double-distilled canola oil obtained in Example 8 and the double-distilled reference oil obtained in Example 9 from T=0 to 4 days. Test samples were held during this period at ambient temperature on a light box and under fluorescent tube lighting. The m/z 58 molecular ion was analysed, and the mass chromatogram clearly shows emergence of propanal at RT 1.37 mins. Propanal development is quantified in the table below, and the data are shown in FIG. 1. The DHA canola oil released substantially lower amounts of propanal demonstrating the improved stability of the canola oil as compared to the reference.

TABLE-US-00007 Time point (days) 0 2 4 DHA Canola oil (ppm propanal) 32.000 38.000 185.000 Reference oil (ppm propanal) 83.000 294.000 829.000

[0155] The DHA Canola oil shows superior stability to oxidation compared with the reference oil.

Example 12—Refinement of DHA Canola Oil

[0156] A portion of the canola oil obtained in Example 1 was refined prior to undergoing further enrichment. The refinement process involved degumming, alkali refinement, bleaching and deodorisation.

[0157] Acid Degumming

[0158] Degumming is the removal of non-hydratable and hydratable phosphatides from the oil. The dried crude oil obtained in Example 1 was heated to 53±2° C. and 0.2% of a 50% citric acid solution was added. After approximately 30 minutes of mixing, 2.0% of heated (53±2° C.) softened water was added and mixed for approximately 30 minutes. The oil was heated to 67±3° C. during the hold and then centrifuged.

[0159] Acid Pretreat/Refining

[0160] Refining is the removal of free fatty acids following their saponification with caustic to make them water-soluble and their subsequent removal by centrifugation. An acid pretreatment step was used to continue the hydration of the phosphatides. The degummed oil was heated to 65±5° C. and 0.1% of 85% phosphoric acid added, and mixed for a total of 30 minutes. After the acid addition and hold time, 20 Be′ (Baumé; 14.4%, w/w) sodium hydroxide was added to neutralise the free fatty acids plus a 0.05% (w/w) excess. The caustic and oil were then mixed for an additional 15 minutes. The oil was heated to 62±2° C. during the 15-minute hold, and then the oil was centrifuged.

[0161] Trisyl Silica Treatment

[0162] Trisyl silica treatment was performed for the further removal of soaps, to levels compatible with bleaching. Trisyl pretreatment was combined with the bleaching step. The refined oil was heated to 68±5° C. and treated with 0.3% of Trisyl 300. The oil/Trisyl was mixed for approximately 15 minutes, and then bleaching was continued.

[0163] Bleaching

[0164] Refined oil was treated with adsorptive clay for the removal of peroxides, phosphatides, colour bodies and traces of soap. An acid pretreatment step was used to continue the hydration of the phosphatides. The Trisyl pretreated oil was mixed with 0.2% (w/w) of a 50% citric acid solution. After 15 minutes of mixing, 2% (w/w) of Tonsil Supreme 126 FF bleaching clay was added. The mixture was then heated to 90±2° C. under vacuum and held for approximately 30 minutes. The oil was cooled to 60±2° C., vacuum broken with nitrogen, 1.0 kg of filter aid added and filtered. Pressure Vessel: 500 L Cherry-Burrell pressure vessel, steam or cooling water jacket, all 316 stainless construction with impeller and baffles for mixing, mfg's serial #E-227-94. Filter Press: 24″ Polypropylene Sperry Filter Press, capacity 4.8 cu ft filter, paper and cloth supports were used.

[0165] Deodorizing

[0166] The bleached oil was subjected to sparging with steam at high temperature and low pressure to remove odoriferous components, flavour components, and additional free fatty acids. Colour is also reduced by heat bleaching at elevated temperatures. The half of the bleached oil was deodorised at 180±2° C. for 60 min with 1% sparge steam and Fatty Acid Composition (FAC) was monitored. Deodoriser Vessel (OD4): 400 L Coppersmithing vacuum rated vessel, steam or cooling water jacket, all 316 stainless construction. A slight decrease of DHA level was observed at 180° C. for 60 min hold. Then another trial was conducted at 180° C. for 30 min hold. The product was packaged under nitrogen in 20-L plastic HDPE pails and stored in a cooler at 4° C.

Example 13—Refinement of Original Reference Blend Oil

[0167] A portion of the reference blend described in Example 2 was refined prior to undergoing further enrichment. In the refinement process the reference blend was subjected to refinement under the same conditions as shown in the preceding Example.

Example 14—Fatty Acid Compositions of the RBD DHA Canola Oil and RBD Reference Blend

[0168] The fatty acid compositions of the RBD DHA Canola oil (of Example 12) and the RBD reference blend oil (of Example 13) were analysed. The results are shown below.

TABLE-US-00008 RBD DHA RBD Reference Fatty Acid Canola oil (wt %) oil (wt %) Palmitic C16:0 4.23 9.22 Stearic C18:0 2.52 3.89 Oleic C18:1n9c 42.90 31.62 Cis-vaccenic C18:1n7c 3.01 1.96 Linoleic C18:2n6c 7.15 12.18 GLA C18:3n6 0.54 0.00 ALA C18:3n3 19.95 22.51 Arachidic C20:0 0.72 0.38 SDA C18:4n3 2.25 0.17 Gondoic C20:1n9c 1.28 0.71 Behenic C22:0 0.31 0.22 ETA C20:4n3 1.08 0.00 Erucic C22:1n9c 0.00 0.00 EPA C20:5n3 0.47 1.67 DPA3 C22:5n3 0.96 0.41 DHA C22:6n3 9.33 9.20 Other 3.32 5.86

[0169] References to “RBD” in connection with the Examples (and the accompanying figures) mean that the product in question was obtained directly or indirectly from the “refined” products of either Example 12 (for Canola oils) and Example 13 (for reference blends).

Example 15—Chemical Trans-Esterification of RBD Canola-DHA Oil

[0170] To a dry, nitrogen flushed Buchi CR101 chemreactor fitted with a mechanical stirrer was added absolute ethanol (12.5 L) and the refined (“RBD”) triglyceride canola-DHA oil obtained in Example 12 (5.00 kg) and the mixture stirred.

[0171] To the above mixture was added sodium ethoxide (150 g) which was rinsed into the reactor with further absolute ethanol (2.5 L) and stirring continued for 16 hr at ambient temperature. A .sup.1H NMR spectrum recorded of a sample taken from the mixture indicated the reaction was complete.

[0172] The trans-esterification procedure was performed on approx. 5 kg of RBD canola-DHA oil. To the resulting crude reaction mixture was added 40-60° C. boiling point petroleum spirits (pet. spirit, 10 L) and water (10 L) and the mixture carefully acidified to pH 7 with 10% hydrochloric acid (870 mL in total required, Merck Universal Indicator strips, pH 0-14) with thorough mixing.

[0173] The resulting mixture was allowed to stand in the reactor, after which 2 phases formed. The pet. spirit layer was removed and the aqueous layer further extracted with pet. spirit (3×5 L). The combined pet. spirit layers were returned to the reactor and evaporated in vacuo to low volume (approx. 10 L). The resulting concentrated solution was drained from the reactor, dried over anhydrous magnesium sulphate (approx. 1 kg), filtered and concentrated in vacuo to give a light pale yellow oil (yield: 99%).

Example 16—Chemical Trans-Esterification of RBD Reference Blend Oil

[0174] To a dry, nitrogen flushed Buchi CR101 chemreactor fitted with a mechanical stirrer was added absolute ethanol (12.5 L) and the RBD triglyceride reference blend oil obtained according to Example 13 (approx. 5 kg) and the mixture stirred.

[0175] To the above mixture was added sodium ethoxide (150 g) which was rinsed into the reactor with further absolute ethanol (2.5 L) and stirring continued for 16 hr at ambient temperature. A .sup.1H NMR spectrum recorded of a sample indicated little or no reaction had taken place. Further sodium ethoxide (57 g) was added to the mixture and stirring continued.

[0176] After an additional 5 hrs, a .sup.1H NMR spectrum of a sample indicated the reaction was 75% complete. Further sodium ethoxide (60 mL of a 21% solution in ethanol) was added to the mixture and stirring continued for 3 days, after which time the reaction was complete.

[0177] Example Product Isolation from RBD Reference Blend Chemical Trans-Esterification

[0178] The trans-esterification procedure was performed on approx. 5 kg of RBD reference blend oil. To the resulting crude reaction mixture was added pet. spirit (15 L) and water (3.3 L) and the mixture carefully acidified to pH 7 with 10% hydrochloric acid (910 mL in total required) with thorough mixing.

[0179] The resulting mixture was allowed to stand in the reactor, after which 2 phases formed. The pet. spirit layer was removed and the aqueous layer further extracted with pet. spirit (2×7.5 L). The combined pet. spirit layers were returned to the reactor and evaporated in vacuo to low volume (approx. 10 L). The resulting concentrated solution was drained from the reactor, dried over anhydrous magnesium sulphate (approx. 1 kg), filtered and concentrated in vacuo to give a light pale yellow oil (yield: 99%).

Example 17—Distillation of Transesterified RBD Canola Oils

[0180] Standard Procedure for the Removal of More Volatile Components of Fatty Acid Ethyl Esters (FAEE) Mixtures by Vacuum Distillation

[0181] The fatty acid ethyl esters (FAEE) from the RBD canola-DHA (obtained in Example 15) were subjected to distillation under the following conditions. Separation by distillation was achieved by passing the trans-esterified oil through a Pope 2 inch (50 mm) wiped film still under vacuum equipped with 2×1000 ml collection flasks collecting the distillate and residue. Each was analysed for fatty acid composition.

[0182] Vacuum was supplied by an Edwards 3 rotary pump and the vacuum measured by an ebro vacumeter VM2000.

[0183] The oil was fed into the still by a Cole-Palmer Instrument Company easy-load II peristaltic pump at 4 mL/min with the still motor set to 325 rpm with water condenser used to condense the distillate. The feed was continued until such time as one or other of the receiver flasks was full.

[0184] RBD canola-DHA FAEE was distilled under these conditions with the heater bands initially set to 152° C. to obtain a 50:50 split of distillate:residue. A portion of the residue from this distillation was again subjected to the removal of more volatile components by distillation under the standard conditions with the temperature of the heater bands set to 152° C. The total time of distillation was approx. 90 minutes.

TABLE-US-00009 Distillation Feed Distillate Residue First 1596.6 729.9 855.9 Second 851.3 503.5 343.1

Example 18—Distillation of Transesterified RBD Reference Blend-Derived FAEE

[0185] The fatty acid ethyl esters (FAEE) from the RBD reference blend (obtained in Example 16) were subjected to distillation under the same conditions as shown in the preceding Example.

[0186] RBD reference blend FAEE was distilled under these standard conditions with the heater bands initially set to 152° C. to obtain a 50:50 split of distillate:residue. The residue from this distillation was again subjected to the removal of more volatile components by distillation under the standard conditions. The objective was to obtain a 50:50 split of distillate:residue. The distillation was mostly performed with the heater bands set to 152° C. The total time of distillation was approx. 200 minutes.

TABLE-US-00010 Distillation Feed Distillate Residue First 1195.1 674.7 504.6 Second 496.4 297.2 197.4

Example 19—Fatty Acid Composition Analysis for the Enriched RBD Oils

[0187] The fatty acid compositions of the products obtained in Examples 17 and 18 were analysed. The results are shown below.

TABLE-US-00011 DHA Canola oil Reference oil Fatty Acid (wt %) (Example 17) (wt %) (Example 18) Palmitic C16:0 0.78 2.27 Stearic C18:0 2.09 3.29 Oleic C18:1n9c 29.57 23.52 Cis-vaccenic C18:1n7c 2.14 1.50 Linoleic C18:2n6c 4.90 8.80 GLA C18:3n6 0.36 0.00 ALA C18:3n3 14.34 16.87 Arachidic C20:0 1.56 0.83 SDA C18:4n3 1.44 0.00 Gondoic C20:1n9c 2.48 1.40 Behenic C22:0 1.12 0.85 ETA C20:4n3 1.93 0.15 Erucic C22:1n9c 0.00 0.13 EPA C20:5n3 0.76 2.75 DPA3 C22:5n3 3.02 1.06 DHA C22:6n3 27.93 28.18 Other 5.58 8.40

Example 20—Oil Stability Assessment

[0188] Headspace analysis was conducted on the enriched products described in Examples 17 and 18 accordance with the method described in Example 11.

[0189] The table below summarises the results obtained from the RBD canola oil obtained in Example 17 and the RBD reference oil obtained in Example 18 from T=0 to 3 days. Test samples were held during this period at ambient temperature on a light box and under fluorescent tube lighting. The m/z 58 molecular ion was analysed, and the mass chromatogram clearly shows emergence of propanal at RT 1.37 mins. Propanal development is quantified in the table below, and the data are shown in FIG. 2. The DHA canola oil released substantially lower amounts of propanal demonstrating the improved stability of the canola oil as compared to the reference.

TABLE-US-00012 Time point (days) 0 3 DHA Canola oil (ppm propanal) 17.000 73.000 Reference oil (ppm propanal) 31.000 267.000

[0190] The DHA Canola oil showed superior stability to oxidation compared with the reference oil.