Two-step emulsification process for preparing infant formula

Abstract

The present invention relates to a two-step emulsification process for preparing a lipid and protein component-containing composition comprising large lipid globules, preferably coated with polar lipids, and to the compositions obtained thereby. Optionally, the lipid and protein component-containing composition is spray-dried. The obtained compositions are for feeding infants and young children.

Claims

1. A process for preparing a lipid and protein component-containing composition, which is an infant or follow-on formula or a growing up milk and which comprises lipid globules, comprising the steps of: a) providing an aqueous phase with a dry matter content of 5 to 75 wt. % (based on total weight of the aqueous phase), which comprises at least one protein component, b) providing a liquid lipid phase, which comprises at least one lipid, c) carrying out a first homogenization step by homogenizing the lipid phase with the aqueous phase in a ratio of 3 to 50% (w/w) lipid to aqueous phase so as to obtain a first lipid and protein component-containing composition comprising lipid globules, wherein at least 10 vol.-% of the lipid globules have a diameter of >12 ?m and/or wherein the lipid globules have a volume-weighted mode diameter from 7 to 15 ?m, and d) carrying out a second homogenization step by homogenizing the first lipid and protein component-containing composition obtained in step c) with an atomizer, wherein the particle size of the lipid globules obtained in step c) is reduced so as to obtain a second lipid and protein component-containing composition comprising lipid globules, wherein less than 10 vol.-% of the lipid globules have a diameter of >12 ?m and/or wherein the lipid globules have a volume-weighted mode diameter from 3 to 6 ?m, wherein the first homogenization step c) is conducted using a rotor stator machine that uses a tip speed of 1 to 15 m/s.

2. The process according to claim 1, wherein less than 20 vol.-% of the lipid globules obtained in step c) have a diameter from 3 to 6 ?m.

3. The process according to claim 1, wherein at least 35 vol.-% of the lipid globules obtained in step c) have a diameter of at least 5 ?m.

4. The process according to claim 1, wherein less than 7 vol.-% of the lipid globules obtained in step c) have a diameter from 1 to 2 ?m.

5. The process according to claim 1, wherein at least 15 vol.-% of the lipid globules obtained in step d) have a diameter from 3 to 6 ?m.

6. The process according to claim 1, wherein less than 35 vol.-% of the lipid globules obtained in step d) have a diameter of at least 5 ?m.

7. The process according to claim 1, wherein at least 7 vol.-% of the lipid globules obtained in step d) have a diameter from 1 to 2 ?m.

8. The process according to claim 1, wherein the first lipid and protein component-containing composition comprising lipid globules obtained in step c) comprises at least 10 vol.-% of lipid globules with a diameter >12 ?m, has a volume-weighted mode diameter of the lipid globules from 7 to 15 ?m, comprises less than 7 vol.-% of lipid globules with a diameter from 1 to 2 ?m, comprises less than 20 vol.-% of lipid globules with a diameter from 3 to 6 ?m and at least 35 vol.-% of lipid globules have a diameter of at least 5 ?m and wherein the second lipid and protein component-containing composition comprising lipid globules obtained in step d) comprises less than 10 vol.-% of lipid globules with a diameter of >12 ?m, has a volume-weighted mode diameter of the lipid globules from 3 to 6 ?m, comprises at least 7 vol.-% of lipid globules with a diameter from 1 to 2 ?m, and comprises at least 20 vol.-% of lipid globules with a diameter from 3 to 6 ?m and less than 35 vol.-% of lipid globules with a diameter of at least 5 ?m.

9. The process according to claim 1, wherein the vol.-% of the lipid globules obtained in step c) with a diameter from 1 to 2 ?m is increased by at least 5% (percentage point) in step d) so as to obtain the second lipid and protein component-containing composition comprising lipid globules.

10. The process according to claim 1, wherein the vol.-% of the lipid globules obtained in step c) with a diameter of >12 ?m is reduced by at least 5% (percentage point) in step d) so as to obtain the second lipid and protein component-containing composition comprising lipid globules.

11. The process according to claim 1, wherein the volume-weighted mode diameter of the lipid globules obtained in step c) is reduced by at least 2 ?m in step d) so as to obtain the second lipid and protein component-containing composition comprising lipid globules.

12. The process according to claim 1, wherein the vol.-% of the lipid globules obtained in step c) with a diameter from 3 to 6 ?m is increased by at least 5% (percentage point) in step d) so as to obtain the second lipid and protein component-containing composition comprising lipid globules.

13. The process according to claim 1, wherein the vol.-% of the lipid globules obtained in step c) with a diameter of at least 5 ?m is reduced by at least 25% (percentage point) in step d) so as to obtain the second lipid and protein component-containing composition comprising lipid globules.

14. The process according to claim 1, wherein the liquid lipid phase provided in step b) is premixed with the aqueous phase provided in step a) prior to mixing step c).

15. The process according to claim 1, wherein the atomizer is a pneumatic atomizer or a rotary atomizer.

16. The process according to claim 15, wherein the pneumatic atomizer is a two-fluid atomizer.

17. The process according to claim 1, wherein immediately after or simultaneously to the second homogenization step a drying step is carried out.

18. The process according to claim 1, wherein the second homogenization step d) is carried out as a spray-drying step so as to obtain a spray-dried lipid and protein component-containing composition comprising lipid globules.

19. The process according to claim 1, wherein the protein component is selected from the group consisting of skim milk, whey, whey protein, whey protein isolate, whey protein hydrolysate, casein, casein hydrolysate and soy protein.

20. The process according to claim 1, wherein the aqueous phase comprises at least one further component selected from the group consisting of digestible carbohydrates, non-digestible carbohydrates, vitamins and minerals.

21. The process according to claim 1, wherein subsequent to step a) and prior to step c) the aqueous phase is sterilised or pasteurised.

22. The process according to claim 1, wherein the aqueous phase, the lipid phase, or the aqueous and the lipid phase comprise polar lipids, in particular phospholipids in an amount of 0.5 to 20 wt. % (based on total lipid of the composition).

23. The process according to claim 1, wherein the tip speed is 7 to 15 m/s.

Description

(1) The invention is further described by way of the following example and the accompanying FIGURE.

(2) The FIG. shows:

(3) FIGURE shows a flow scheme of the present process, also described in the example, wherein comp. is short for components and panels with solid lines represent the aqueous phase, panels with bold lines represent the lipid phase and panels with double lines represent the mixture, i. e. the emulsion of both phases.

EXAMPLE

(4) Process of the present invention (A):

(5) An infant formula was prepared being a powder comprising per kg final product about 4600 kcal, about 210 g lipid, about 525 g digestible carbohydrates, about 39 g non-digestible oligosaccharides and about 150 g protein. The composition was prepared using whey protein concentrate, skimmed milk powder, lactose, a vegetable oil blend (fat) and non-digestible oligosaccharides. Also vitamins, minerals, trace elements as known in the art were used.

(6) An aqueous phase, comprising, protein, digestible carbohydrates and the other ingredients, except the fat and fat soluble vitamins, was prepared as known in the art. The dry matter content of the aqueous phase was between 40 to 60 wt. %. The aqueous phase was pasteurized for 6 minutes at 85? C.

(7) A fat phase was prepared as known in the art. The vegetable oil blend was heated to 60? C. and added to the water phase in a w/w ratio of from 15 to 20 and premixed with a Typhoon propeller mixer. The total solid content of the fat and aqueous phase mixture was between 40 and 60 wt %.

(8) The pre-emulsion was fed into a stator rotor machine (IKA) having a tip speed of 7 to 15 m/s and a slit width of less than 1 mm After the first emulsification step, the product was collected and emulsified a 2n.sup.d time using pneumatic atomizers (2F) at 3 to 4 bar air pressure.

(9) Control Process (B):

(10) In a control experiment (designated B) the material and process parameters exactly as indicated above for the inventive process (A) were used except for a tip speed above 30 m/s.

(11) The table below shows an analysis of the particle size distribution of lipid globules obtained according to the two-step emulsification process according to the present invention (A) which, thus, employs a first lipid globule particle size determining mixing step and a second lipid globule particle size determining atomizing step and a control (B).

(12) TABLE-US-00001 TABLE A, A, B, B, before after before after atom- atom- atom- atom- izing izing izing izing step step delta step step delta Volume- 12.07 3.42 ?8.65 4.40 2.92 ?1.48 based mode diameter ?m 2-12 ?m v % 39.42 48.93 9.51 71.08 52.55 ?18.53 3-6 ?m v % 8.84 23.36 14.52 36.92 27.10 ?9.82 >12 ?m v % 33.68 2.71 ?30.97 1.59 0.06 ?1.53 >5 ?m v % 67.68 20.10 ?47.58 31.79 11.84 ?19.95 1-2 ?m v % 0.4 17.1 16.7 7.8 20.6 12.8 (?m = micrometer; v % = vol.-%) A: two-step homogenization process of the present invention, B: control one-step homogenization process

(13) It is evident that the present process significantly alters the particle size distribution of the first protein and lipid-component containing composition during the second homogenization step, in particular increases the amount of smaller lipid globules and reduces the lipid globule size while in the control process the atomizing step has a much less pronounced effect on the particle size distribution.

(14) In an optional embodiment, the composition obtained after by the second homogenization, that means emulsification step, may be dried, in particular spray-dried or belt-dried.