Oil comprising at least one polyunsaturated fatty acid having at least 20 carbon atoms (LC-PUFA)

Abstract

The present invention relates to an oil comprising at least one polyunsaturated fatty acid having at least 20 carbon atoms (LC-PUFA). It is found that LC-PUFA-containing oil are susceptible to gelling by formation of microscopic crystals during storage ultimately resulting in unfavorable quality and handling properties. This problem has been particularly observed with a microbial oil comprising at least about 25% by weight LC-PUFA and a moisture content of 0.2 to 5% by weight. Surprisingly, it has been found that a LC-PUFA-containing oil as described above is effectively stable and does not show gelling properties under conventional storage conditions, if the oil composition as such contains less than about 8% preferably less than about 5% by weight of free fatty acid in the residual moisture of the oil. Therefore, the present invention is directed to an oil comprising at least about 25% by weight LC-PUFA and a moisture content comprising less than about 8% preferably less than about 5% by weight of free fatty acid.

Claims

1. An oil comprising: at least 25% by weight omega-3 polyunsaturated fatty acids (LC-PUFA), wherein the oil has a residual moisture content which comprises less than 5% by weight of free fatty acid in the residual moisture of the oil, and wherein the oil comprises at least 25% by weight docosahexaenoic acid (DHA), and at least 10% by weight eicosapentaenoic acid (EPA), and wherein the omega-3 polyunsaturated fatty acids are present in the oil in a total amount of at least 500 mg per one gram of oil.

2. The oil according to claim 1, wherein the moisture content of the oil is less than 2% by weight.

3. The oil according to claim 1, wherein the EPA is present in the oil in an amount from 100 mg to 250 mg EPA per one gram of oil, and the DHA is present in the oil in an amount from 250 mg to 400 mg DHA per one gram of oil.

4. The oil according to claim 3, wherein the oil comprises a weight ratio of the EPA:DHA of 1:1 to 1:30 based on total weight of the omega-3 polyunsaturated fatty acids.

5. The oil according to claim 1, wherein the oil is a plant oil.

6. The oil according to claim 1, wherein the oil is a microbial oil.

7. The oil according to claim 6, wherein the microbial oil is produced by Schizochytrium sp.

8. A microbial oil according to claim 6, wherein the residual moisture content of the oil is less than 2% by weight, and wherein the residual moisture comprises less than 5% by weight free fatty acids in the residual moisture.

9. The microbial oil according to claim 6, wherein the omega-3 polyunsaturated fatty acids are present in an amount from 400 mg to 800 mg per one gram of oil.

10. The microbial oil according to claim 6, wherein the oil comprises a weight ratio of the EPA:DHA from at least 1:1 based on total weight of the omega-3 polyunsaturated fatty acids.

11. The microbial oil according to claim 6, comprising at least 10% by weight of a triacylglycerol fraction, wherein at least 12% by weight of the fatty acids in the triacylglycerol fraction is eicosapentaenoic acid, and wherein at least 25% by weight of the fatty acids in the triacylglycerol fraction is docosahexaenoic acid, and wherein less than 5% by weight of the fatty acids in the triacylglycerol fraction is arachidonic acid.

Description

EXAMPLES

Example 1: Production of a Microbial Oil

(1) An unwashed cell broth containing microbial cells (Schizochytrium sp.) at a biomass density of over 100 g/I was heated to 60° C. in an agitated vessel. After heating up the suspension, the pH was adjusted to 7.5 by using caustic soda (50 wt.-% NaOH solution), before an alcalase (Alcalase® 2.4 FG (Novozymes)) was added in liquid form in an amount of 0.5 wt.-% (by weight broth). Stirring was continued for 3 hours at 60° C. After that, the lysed cell mixture was transferred into a forced circulation evaporator (obtained from GEA, Germany) and heated to a temperature of 85° C. The mixture was concentrated in the forced circulation evaporator, until a total dry matter content of about 30 wt.-% was reached. The concentrated lysed cell mixture was transferred into a new vessel, heated up to 90° C. under low shear agitation, while adjusting the pH to 10.5 by adding caustic soda. Low shear agitation was continued for about 30 hours, while keeping the temperature at 90° C. and the pH above 9.0 by adding caustic soda.

(2) After that the resulting demulsified mixture was neutralized by adding sulfuric acid to adjust a pH of 7.5. Phase separation into a light phase, containing the oil, and a heavy phase, containing water, cell-debris, residual oil and salts, was carried out mechanically by using a disc stack separator (Alfa Laval Disc Stack Centrifuge, LAPX 404/Clara 20)

(3) Due to the efficient demulsification, more than 90 wt.-% of the oil could be separated from the biomass without the addition of organic solvents or sodium chloride. And finally, the oil is effectively stable and does not show gelling properties. It contains less than 5% by weight of free fatty acid in the residual moisture of the oil.

Example 2—Microbial Oil as Animal Feed Additive

(4) A specification of a microbial crude oil according to the invention for use as an animal feed additive in aquaculture is shown below.

(5) TABLE-US-00001 DHA + EPA, mg/g oil min. 500 mg/g DHA content, mg/g oil min. 250 mg/g (mind 25% −> 40%) EPA content, mg/g oil min. 100 mg/g (mind 10% −> 25%) Ratio EPA:DHA min 1:4 Ratio EPA:DHA max 1:1 Free fatty acid max 5% Moisture max. 0.75% DPA n-3 <6 Arachidonic Acid, % <2 Stearic acid, % <2.5 Palmitic acid, % <30 Crude Fat >92%