PROCESS FOR PRODUCING A PUFA-CONTAINING FEEDSTUFF BY EXTRUDING A PUFA-CONTAINING BIOMASS

Abstract

In accordance with the invention, it was found, surprisingly, that a polyunsaturated fatty acids (PUFAs)-comprising biomass with other feedstuff components can be extruded at a low energy input of 12-28 Wh/kg to give an extrudate with a very high oil load capacity.

Claims

1-14. (canceled)

15. A process for the preparation of a PUFA-comprising feedstuff, comprising extruding a PUFA-comprising biomass at an energy input of 12-28 Wh/kg, wherein said biomass comprises a sulphate content of 25 to 60 g/kg, based on dry matter, together with further feedstuff components.

16. The process of claim 15, wherein the extrusion takes place at an energy input of 16-24 Wh/kg.

17. The process of claim 15, wherein the PUFA-comprising biomass comprises cells of the taxon Labyrinthulomycetes.

18. The process of claim 17, wherein the PUFA-comprising biomass comprises cells of the genera: Thraustochytrium, Schizochytrium, Aurantiochytrium, Oblongichytrium or Ulkenia.

19. The process of claim 18, wherein the PUFA-comprising biomass comprises cells of the species Aurantiochytrium limacinum.

20. The process of claim 15, wherein the PUFA-comprising biomass employed in the extrusion comprises: a) a total protein content of 33 to 67% by weight; b) a total fat content of 5 to 25% by weight; c) a total starch content of not more than 25% by weight; d) a biomass content of 2 to 24% by weight.

21. The process of claim 20, wherein the PUFA-comprising biomass further comprises one or more of the following: e) a polyunsaturated fatty acid (PUFAs) content of 0.8 to 8% by weight; f) an omega-3 fatty acid content of 0.8 to 8% by weight; g) a DHA content of 0.1 to 4.0% by weight.

22. The process of claim 15, wherein, after extrusion or after a subesquent step in which extrudate is dried, the extrudate is coated with oil in an amount of 3 to 17% by weight, based on the final product.

23. A feedstuff extrudate comprising a PUFA-comprising biomass, wherein the PUFA-comprising biomass comprises cells of the taxon Labyrinthulomycetes and has an oil load capacity of at least 0.25 g of oil per g of extrudate.

24. The feedstuff extrudate of claim 23, wherein said biomass comprises an oil load capacity of at least 0.35 g of oil per g of extrudate.

25. The feedstuff extrudate of claim 23, wherein the PUFA-comprising biomass comprises cells of the family Thraustochytriaceae.

26. The feedstuff extrudate of claim 23, wherein the PUFA-comprising biomass comprises cells of the genera: Thraustochytrium, Schizochytrium, Aurantiochytrium, Oblongichytrium or Ulkenia.

27. The feedstuff extrudate of claim 23, wherein the PUFA-comprising biomass comprises cells of the species Aurantiochytrium limacinum.

28. The feedstuff extrudate of claim 23, wherein the biomass has a sulphate content of 25 to 60 g/kg based on the dry matter.

29. The feedstuff extrudate of claim 23, comprising: a) a total protein content of 30 to 60% by weigh; b) a total fat content of 15 to 35% by weight; c) a total starch content of not more than 25% by weight; d) a biomass content of 2 to 22% by weight.

30. The feedstuff extrudate of claim 29, further comprising one or more of: e) a polyunsaturated fatty acid (PUFAs) content of 2 to 12% by weight; f) an omega-3 fatty acid content of 1 to 6% by weight; g) a DHA content of 0.5 to 3% by weight.

31. The feedstuff extrudate of claim 23, comprising: a) a total protein content of 40 to 50% by weight; b) a total fat content of 22 to 28% by weight; c) a total starch content of 7 to 13% by weight; d) a Thraustochytriaceae biomass content of 10 to 16% by weight; and further comprising one or more of the following: e) a polyunsaturated fatty acid (PUFA) content of 5 to 8% by weight; f) an omega-3 fatty acid content of 2.5 to 4% by weight; g) a DHA content of 1.2 to 2.0% by weight.

32. A method of growing animals by feeding them a feedstuff extrudate comprising a PUFA-comprising biomass, wherein the PUFA-comprising biomass comprises cells of the taxon Labyrinthulomycetes and has an oil load capacity of at least 0.25 g of oil per g of extrudate.

33. The method of growing animals of claim 32, wherein the PUFA-comprising biomass comprises cells of the family Thraustochytriaceae and has a sulphate content of 25 to 60 g/kg, based on the dry matter and wherein the feedstuff extrudate comprises: a) a total protein content of 30 to 60% by weigh; b) a total fat content of 15 to 35% by weight; c) a total starch content of not more than 25% by weight; and d) a biomass content of 2 to 22% by weight.

34. The method of growing animals of claim 32, wherein the biomass comprises cells of the species Aurantiochytrium limacinum and wherein the feedstuff extrudate further comprises one or more of the following: e) a polyunsaturated fatty acid (PUFAs) content of 2 to 12% by weight; f) an omega-3 fatty acid content of 1 to 6% by weight; g) a DHA content of 0.5 to 3% by weight.

Description

WORKING EXAMPLES

Example 1

Production of the Biomass by Fermentation of Aurantiochytrium limacinum SR21 in a Medium with a High Sulphate Content, and Subsequent Drying of the Biomass

[0158] The cells were cultured for approximately 75 h in a fed-batch process using a steel fermenter with a fermenter volume of 2 litres at a total initial biomass of 712 g and an obtained total final biomass of 1.3-1.5 kg. During the process, a glucose solution (570 g/kg glucose) was metered in (“fed-batch process”).

[0159] The composition of the starting medium was as follows:

[0160] Medium 1: 20 g/kg glucose; 4 g/kg yeast extract; 16 g/kg sodium sulphate; 2 g/kg ammonium sulphate; 2.46 g/kg magnesium sulphate (heptahydrate); 0.45 g/kg potassium chloride; 4.5 g/kg potassium dihydrogenphosphate; 0.1 g/kg thiamine (HCl); 5 g/kg trace element solution.

[0161] The composition of the trace element solution was as follows: 35 g/kg aqueous hydrochloric acid (37%); 1.86 g/kg manganese chloride (tetrahydrate); 1.82 g/kg zinc sulphate (heptahydrate); 0.818 g/kg sodium EDTA; 0.29 g/kg boric acid; 0.24 g/kg sodium molybdate (dihydrate); 4.58 g/kg calcium chloride (dihydrate); 17.33 g/kg iron sulphate (heptahydrate); 0.15 g/kg copper chloride (dihydrate).

[0162] The cultivation was carried out under the following conditions: Cultivation temperature 28° C.; aeration rate 0.5 vvm, stirrer speed 600-1950 rpm, pH control during the growth phase at 4.5 using ammonia water (25% v/v). The fermentation was carried out until a biomass density of 116 g/l had been reached.

[0163] After the cultivation, the fermentation liquors were heated to 60° C. for 20 minutes so as to prevent a further activity of the cells.

[0164] This was followed by a two-step drying of the biomass: First, the fermentation liquor was concentrated by evaporation to a dry matter of approximately 20% by weight. Thereafter, the concentrated fermentation liquor was spray-dried using a Production Minor™ Spray Dryer (GEA NIRO) at an inlet temperature of the drying air of 340° C. Spray-drying thus gave a powder with more than 95% by weight of dry matter.

[0165] To determine the sulphate content of the biomass obtained, the sulphur content of the biomass was determined as per DIN ISO 11885. To this end, an aliquot of the biomass was first hydrolysed with nitric acid and hydrogen peroxide at 240° C. under pressure. The sulphur content determined amounted to 11 g/kg biomass, which corresponds to a sulphate content of 33 g/kg biomass.

Example 2

Feedstuff Preparation by Extrusion

[0166] The feedstuff mixtures particularized in Table 1 were prepared. Besides the biomass of Example 1 to be employed in accordance with the invention, two further commercially available Labyrinthulea biomasses and fish oil as are currently still usual source of omega-3 fatty acids were tested for comparison purposes.

[0167] In each case, the feedstuff mixtures were prepared by mixing the components—with the exception of the oils—using a twin-screw mixer (Model 500L, TGC Extrusion, France). The mixtures thus obtained were subsequently comminuted to particle sizes of below 250 μm using a hammer mill (Model SH1, Hosokawa-Alpine, Germany).

TABLE-US-00001 TABLE 1 Feedstuff compositions employed in the extrusion process (Data in % by weight) Constituent M1 M2 M3 M4 Fish meal 10.00 10.00 10.00 10.00 Soya protein concentrate 23.10 23.20 23.10 20.27 Pea protein concentrate 15.00 15.00 15.00 15.00 Wheat gluten 9.90 9.90 9.90 9.90 Wheat flour 18.12 10.82 10.55 16.46 Fish oil 10.00 — — — Biomass from Example 1 — 16.00 — — Commercially available biomass 1 — — 16.74 — Commercially available biomass 2 — — — 13.52 Rape oil 10.00 11.00 11.00 11.00 Vitamin/mineral premix 1.00 1.00 1.00 1.00 Dicalcium phosphate 2.00 2.00 2.00 2.00 Yttrium oxide 0.03 0.03 0.03 0.03 DL-methionine 0.35 0.36 0.33 0.33 Aquavi-Lys 0.17 0.35 0.08 0.19 Tryp-Amino 0.09 0.09 0.08 0.09 L-Histidine 0.24 0.25 0.19 0.21

[0168] For the extrusion, in each case 140 kg were employed per feedstuff. Extruding was carried out by means of a twin-screw extruder (CLEXTRAL BC45) with a screw diameter of 55.5 mm and a maximum flow rate of 90-100 kg/h. Pellets 4.0 mm in size were extruded. To this end, the extruder was equipped with a high-speed cutter so as to convert the product into the desired pellet size.

[0169] Various extrusion parameters were then tested so as to find out the extrusion conditions under which an optimal oil load capacity of the extrudate obtained may be obtained. Surprisingly, it has been found that an optimal oil load capacity can be achieved with a very low energy input. The energy input here was markedly lower than when using fish oil. Furthermore, the optimal energy input in a biomass with a high sulphate content preferably to be used in accordance with the invention was, again, markedly lower than in the case of commercially available Thraustochytriales biomasses. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Energy inputs for the preparation of pellets with the desired oil load capacity Barrel Barrel Rota- Amount 1 2 Feeder tional of Amper- Temp Temp rate speed water age SME Diet (° C.) (° C.) (kg/h) (rpm) (0-10) (A) (Wh/kg) M1 31 116-118  112 215 9 11 34.6 M2 32 98-104 141 253 5 7 20.6 M3 32 97-102 136 255 5 8 24.6 M4 31 99-107 133 253 5 8 24.9

[0170] The parameter “SME” is the specific mechanical energy. It is calculated as follows:

[00001]$\mathrm{SME}.Math..Math.\left(\mathrm{Wh}.Math.\text{/}.Math.\mathrm{kg}\right)=\frac{U\times I\times \cos .Math..Math.\Phi .Math.\frac{\mathrm{Test}.Math..Math.\mathrm{SS}}{\mathrm{Max}.Math..Math.\mathrm{SS}}}{\mathrm{Qs}}$

where

[0171] U: Working voltage of the motor (presently 460 V)

[0172] I: Amperage of the motor (A)

[0173] cos Φ: Theoretical output of the extruder motor (presently 0.95)

[0174] Test SS: Test speed (rpm) of the rotating screws

[0175] Max SS: Maximum speed (267 rpm) of the rotating screws

[0176] Q.sub.S: Inlet flow rate of the feed mash (kg/h)

[0177] After the extrusion, the extrudate was dried in a vibrating fluidized-bed dryer (Model DR100, TGC Extrusion, France).

[0178] Thereafter, the extrudate was cooled and then coated with oil by means of vacuum coating (vacuum coater PG-10VCLAB, Dinnisen, The Netherlands). Here, it was found that more than 0.35 g of oil can be applied to 1 g of extrudate.

Example 3

Determination of the Abrasion Resistance and Water Stability

[0179] The abrasion resistance was determined as follows: Before being loaded with oil, the dried extrusion product was exposed to a mechanical stress using the Holmen pellet tester (Borregaard Lignotech, Hull, UK). Before the test was carried out, the samples were sieved so as to remove any adhering fines. The prepared samples (100 g) were subsequently introduced into the pellet tester using a 2.5 mm filter screen. The pellets were subsequently conveyed for 30 seconds at high air speed through a small tube with rectangular quadrant pipe. Thereafter, the abraded material was determined by weighing. The abrasion resistance was indicated as PDI (Pellet Durability Index), defined as the percentage amount of sample remaining on the filter screen. The test was carried out in each case with three samples, and the mean was then calculated.

[0180] The stability in water was carried out with the oil-loaded samples. The method was carried out essentially as described by Baeverfjord et al. (2006; Aquaculture 261, 1335-1345), with minor modifications. 10 g samples were placed into metal infusion baskets of mesh size 0.3 mm. The infusion baskets were subsequently placed into a plastic tub filled with water so that the samples were fully covered by water. The tub was subsequently exposed to 30 minutes of shake agitation of 30 shake units per minute. Thereafter, the samples were dried carefully with blotting paper and subsequently weighed before and after they had been subjected to 24 hours of oven drying at a temperature of 105° C. The water stability was calculated as the difference of the sample's dry weight before and after incubation in water and given in per cent of the dry weight of the sample employed before incubation with water.

[0181] The results are shown in Table 3.

TABLE-US-00003 Sample M1 M2 M3 M4 Abrasion 90.0 93.3 88.3 85.2 resistance [%] Water stability [%] 95.7 98.5 93.8 90.2

[0182] It can be seen that a feedstuff according to the invention has a markedly higher abrasion resistance and water stability than feedstuffs which comprise a commercially available Labyrinthulea biomass or fish oil as the source of omega-3 fatty acids.