Process for preparing infant formula using a rotary atomizer

Abstract

The present invention relates to a process for preparing a spray-dried lipid and protein component-containing composition using a rotary atomizer, which composition comprises large lipid globules, preferably coated with polar lipids, and to the compositions obtained thereby. The obtained compositions are preferably for feeding infants and young children.

Claims

1. A process for preparing a spray-dried lipid and protein component-containing composition, selected from a group consisting of a spray-dried infant formula, a follow-on formula, and a growing up milk, the spray-dried lipid and protein component-containing composition having liquid globules, the process comprising: spray-drying a lipid and protein component-containing composition having lipid globules with an atomization system employing a rotary atomizer so as to obtain a spray-dried lipid and protein component-containing composition having lipid globules with a volume-weighted mode diameter of at least 1.0 μm, and/or lipid globules wherein at least 45 vol. % of said lipid globules have a diameter from 2 to 12 μm, wherein the lipid and protein component-containing composition to be atomized has a dry matter content of 30 to 65 wt. %.

2. The process according to claim 1, wherein the rotary atomizer is operated with a tip speed of 50 to 120 m/s.

3. The process according to claim 1, wherein an inlet temperature for a drying gas used for spray-drying is at least 180° C.

4. The process according to claim 1, wherein the lipid and protein component-containing composition used for spray-drying is prepared by a process, comprising: a) providing an aqueous phase with a dry matter content of 10 to 60 wt. % based on total weight of the aqueous phase, which includes at least one protein component; b) providing a liquid lipid phase, which includes at least one lipid; and c) mixing the lipid phase with the aqueous phase in a ratio of 5 to 50% (w/w) using a static mixer or an inline mixer with at least one mixing head so as to obtain a lipid and protein component-containing composition comprising lipid globules.

5. The process according to claim 4, wherein the liquid lipid phase provided in step b) is fed into the aqueous phase provided in step a) prior to or during mixing step c).

6. The process according to claim 4, wherein the inline mixer with at least one mixing head is used at 4,000 to 15,000 rpm.

7. The process according to claim 4, wherein the lipid globules obtained in step c) have a volume-weighted mode diameter of at least 1.0 μm and/or wherein at least 45 vol. % of the lipid globules obtained in step c) have a diameter from 2 to 12 μm.

8. The process according to claim 4, 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.

9. The process according to claim 4, wherein the aqueous phase comprises at least one further component selected from the group consisting of digestible carbohydrates, non-digestible carbohydrates, vitamins and minerals.

10. The process according to claim 4, wherein the liquid lipid phase is heated to a temperature of at least 40° C. prior to being fed into the aqueous phase.

11. The process according to claim 4, wherein the inline mixer with at least one mixing head in step c) mixes the lipid and aqueous phases with a tip rotor speed of 20 to 50 m/s.

12. The process according to claim 4, wherein the static mixer used in step c) is operated with a flow rate of 1.5 to 8 l/min.

13. The process according to claim 4, wherein the lipid and protein component-containing composition obtained in step c) is obtained at a low pressure of at most 10 bar.

14. The process according to claim 4, wherein the aqueous phase is provided with a dry matter content of 30 to 50 wt. % based on total weight of the aqueous phase.

15. The process according to claim 4, wherein subsequent to step a) and prior to step c) the aqueous phase is sterilised or pasteurised.

16. The process according to claim 4, wherein the lipid and protein component-containing composition obtained in step c) is reheated to 75 to 85° C.

17. The process according to claim 4, 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.

18. The process according to claim 4, wherein the aqueous phase further comprises lactose.

Description

(1) The figures show:

(2) FIG. 1 shows a flow scheme of a process of the present invention, wherein comp. is short for components and panels with solid lines represent the aqueous phase, panels with double lines represent the lipid phase and panels with bold lines represent the mixture, i. e. the emulsion of both phases and

(3) FIG. 2 shows the particle size distribution of various preparations obtained after subjecting them to a rotary atomization system.

EXAMPLE

(4) An infant formula was prepared being a powder comprising per kg final product about 4800 kcal, about 247 g lipid, about 540 g digestible carbohydrates, about 41 g non-digestible oligosaccharides and about 97 g protein. The composition was prepared using butter milk serum powder enriched in milk phospholipids, a vegetable oil blend (fat), demineralised whey powder (protein), lactose, and non-digestible oligosaccharides. Also vitamins, minerals, trace elements as known in the art were used.

(5) The amount of butter milk serum powder was such that 1.62 wt. % phospholipids based on total lipids were present in the final composition.

(6) An aqueous phase, comprising the butter milk powder, protein and digestible carbohydrates and the other ingredients, except the fat and fat soluble vitamins, was prepared as known in the art and heat treated to prevent bacterial contamination, namely by an Ultra High Temperature (UHT) treatment, as known in the art, after which an evaporation step was applied. The dry matter content of the aqueous phase was between 30 to 48 wt. % after the evaporation step. The mixture was heated to 50° C.

(7) A fat phase was prepared as known in the art. The vegetable oil blend was also heated to 50° C. and added to the water phase in a w/w ratio of between 15 to 30 by injection and a centrifugal booster pump. The total solid content of the fat and aqueous phase mixture was between 40 and 60 wt %.

(8) Accordingly, the aqueous and fat phase were fed into the inline mixer (Ystral Z80) comprising one mixing head. The rotor stator design of the inline mixer had 3 rows of teeth. The aqueous and fat phase were mixed with a tip speed of 20 to 50 m/s (resulting in a low shear rate 25 s.sup.−1) in order to emulsify the lipid phase into the aqueous phase and thereafter pumped with a positive displacement pump, a mono pump, with a pressure of about 8 bar to the heater.

(9) The oil in water mixture was subsequently fed via the concentrate heater to the spray dryer, driven by the pump used downstream of the inline mixer (FIG. 1).

(10) The emulsion was atomized with a low shear atomization system employing a wheel atomizer in a NIRO-25 spray dryer and dried with the inlet temperature of the drying gas being 175° C. or 193° C.

(11) Atomization was performed with a rotary atomizer with different settings. The setting variations were dryer inlet temperature and rotational speed of the rotary atomizer.

(12) The size of the lipid globules in the final powder, after reconstitution with water, was measured with a Mastersizer 2000 (Malvern Instruments, Malvern UK). About 60% of the lipid globules based on lipid volume had a diameter from 2 and 12 μm.

(13) Settings were according to the following overview of the table and after measurement a corresponding mode diameter based on volume of lipid globules was found.

(14) TABLE-US-00001 TABLE 1 Tip Wheel Volume-weighted Sample speed speed Dryer inlet Mode diameter code (m/s) (rpm) temp. (μm) Setting 1 - 14.9 90 m/s 14000 High 3.143 product (193° C.) Setting 2 - 14.10 70 m/s 11000 High 3.645 product (193° C.) Setting 3 - 14.11 90 m/s 14000 Low (175) 3.361 product

(15) After reconstitution the particle size distribution given in FIG. 2 was found.

(16) All settings resulted in lipid droplets with a volume-weighted mode diameter of more than 1 μm, in particular from 2 to 5, in particular 3 to 4 μm.

(17) The example shows that using a wheel atomizer in a spray dryer can produce a powder which has a desired, natural-like mode diameter based on volume of lipid globules after reconstitution of the powder with water.