Process for producing infant formula products and acidic dairy products from milk

Abstract

The invention pertains to a process for simultaneous producing an infant formula product and an acidic dairy product from defatted animal milk, comprising (a) processing the milk into a casein stream, a whey protein stream and a lactose stream, by: (i) subjecting the defatted animal milk to a filtration step over a microfiltration membrane capable of retaining bacteria and permeating milk proteins, to provide a debacterialized milk as permeate; (ii) subjecting the permeate originating from step (i) to a filtration step over a microfiltration membrane capable of retaining casein and permeating whey proteins, to provide a casein stream as retentate and a permeate comprising whey protein; (iii) fractionating the permeate originating from step (ii) into a whey protein stream and a lactose stream; (b) combining part of the casein stream, at least part of the whey protein stream originating from step (a) and a lactose source to obtain a recombined stream, wherein the lactose source comprises acid whey; (c) using the recombined stream originating from step (b) in the manufacture of the infant formula product; (d) using part of the casein stream originating from step (a) in the manufacture of the acidic dairy product. The invention further concerns the infant formula product obtainable by step (c) of the process according to the invention, and to the acidic dairy product obtainable by step (d) of the process according to the invention.

Claims

1. A process for producing an infant formula product and an acidic dairy product from defatted animal milk, comprising: (a) processing the defatted animal milk into a casein stream, a whey protein stream and a lactose stream, by: (i) subjecting the defatted animal milk to a filtration step over a microfiltration membrane capable of retaining bacteria and permeating milk proteins, to provide a debacterialized milk as permeate; (ii) subjecting the permeate originating from step (i) to a filtration step over a microfiltration membrane capable of retaining casein and permeating whey proteins, to provide a casein stream as retentate and a permeate comprising whey protein; (iii) fractionating the permeate originating from step (ii) into a whey protein stream and a lactose stream; (b) combining part of the casein stream, at least part of the whey protein stream originating from step (a) and a lactose source to obtain a recombined stream, wherein the lactose source comprises acid whey; (c) using the recombined stream originating from step (b) in the manufacture of the infant formula product; (d) using part of the casein stream originating from step (a) in the manufacture of the acidic dairy product.

2. The process according to claim 1, wherein the acid whey is obtained as a liquid stream from a separation step during the manufacture of an acidic dairy product.

3. The process according to claim 1, wherein the acid whey is subjected to demineralization prior to being used as lactose source in step (b).

4. The process according to claim 3, wherein the demineralization comprises at least one of salt precipitation, electrodialysis, lactose crystallization and ion exchange.

5. The process according to claim 3, wherein the acid whey and at least part of the lactose stream originating from step (a) are combined and subsequently subjected to the demineralization prior to being used as lactose source in step (b).

6. The process according to claim 1, wherein the combining of step (b) is done such that the whey protein to casein weight ratio in the recombined stream is in the range of 90:10 to 40:60.

7. The process according to claim 1, wherein step (iii) is performed by ultrafiltration.

8. The process according to claim 7, wherein the ultrafiltration step operates at a volume concentration factor in the range of 20-200.

9. The process according to claim 1, wherein the manufacturing of step (c) includes at least one of drying, concentrating, supplementing with vitamins, minerals, lipids and/or dietary fibres and packaging.

10. The process according to claim 1, wherein the defatted animal milk is the sole protein source for the infant formula product.

11. The process according to claim 10, wherein the defatted animal milk is the sole protein source for the both infant formula product and the acidic dairy product.

12. The process according to claim 4, wherein the demineralization is in combination with nanofiltration.

Description

FIGURES

(1) FIG. 1 depicts a preferred embodiment of the process according to the invention. Dotted arrows indicated preferred embodiments. MF1=microfiltration step (i); MF2=microfiltration step (ii); UF=ultrafiltration; Demin=demineralisation; AD=acidic dairy product; IF=infant formula product; L=lactose source. The different streams are represented by numbers 1-9: 1=defatted animal milk; 2=debacterialized milk; 3=microfiltration retentate; 4=microfiltration permeate; 5=ultrafiltration retentate; 6=ultrafiltration permeate; 7=recombined stream; 8=acid whey; 9=demineralized lactose.

(2) FIG. 2 depicts the results of Example 2, wherein the protein fraction of an infant formula according to the invention (solid line) was found to be more slowly digested then a conventional formula (dotted line). Int=intensity of the combined protein bands in an SDS-PAGE gel, in % based on the intensity at t=0 min.

EXAMPLES

Example 1

(3) Defatted Milk Processing into a Native Whey Protein Stream

(4) Whole raw milk (purchased from Dairygold) was processed into a WPC fraction according to the following process. Milk and subsequent fractions were stored at 4° C. throughout production. Whole milk was skimmed using typical GEA Westfalia Separator @55° C. and cooled to 4° C. Skim milk was subjected to microfiltration to separate casein from both whey and lactose. Microfiltration membrane used was a 0.08 μM Synder membrane FR (PVDF 800 kDa) spiral wound membrane. However, any microfiltration membrane could be used provided casein was retained while whey/lactose/soluble minerals permeate efficiently. Microfiltration retentate was kept as the casein fraction. Microfiltration permeate contained whey and lactose.

(5) Operating temperature was 10° C. and concentration factor (CF) was 3. CF factor achieved related to required final concentration of casein protein in microfiltration retentate. Microfiltration permeate was then subjected to ultrafiltration to separate whey protein from lactose at operating temperature of 10° C. with VCF of 90. CF factor achieved related to required final concentration of whey protein in ultrafiltration retentate. In this trial a WPC70 was produced.

(6) The ultrafiltration membrane used was a 10 kDa Synder membrane ST (PES 10 kDa) spiral wound membrane. However, any ultrafiltration membrane could be used provided whey proteins were retained and lactose and minerals permeate efficiently. Diafiltration medium was added to improve separation efficiency of membranes (200% of original starting skim milk volume). Concentrated liquid WPC70 (DM 11%) was stored at 4° C.

(7) Liquid WPC 70 was heated to 30° C. and spray dried at 11% DM. Spray dryer used was a single stage pilot scale dryer operated with an inlet temperature of 185° C. and outlet temperature of 90° C. Dried WPC70 was then recombined with a casein source, lactose and minerals to match those of infant formulae compositions.

(8) A commercially available infant formula (Frisolac Gold, casein at 4.2 g/100 g dry product or 0.55 g/100 ml ready-to-feed, whey protein at 6.4 g/100 g dry product or 0.83 g/100 ml ready-to-feed) was purchased and used in comparison to a composition comprising the whey proteins obtained according to above described process of Example 1.

Example 2

(9) Digestibility Test

(10) This protocol describes the simulation of digestion processes by use of the Multi-fermenter fed-batch from DasGip. The conditions used are specifically designed to simulate the digestion of a dose of infant formula of 200 ml by an infant of 6-12 months of age. The volumes described in this protocol are all scaled down by a factor 0.175 to permit usage of 0.1 litre reactors with overhead magnetic agitation with a starting volume of 35 ml Infant Formula (IF).

(11) Preparation of Solutions

(12) Fresh stock solutions as used during the digestibility test are prepared before the test is started. 20× concentrated gastric electrolyte solution with a density of 1.05438 g/ml is prepared in demi-water by dissolving 62 g NaCl, 22 g KCl, 3 g CaCl.sub.2.2H.sub.2O by stirring into demi-water until a volume of 1000 ml is reached. 1 L saliva electrolyte (1×) is prepared in demi-water by dissolving 6.2 g NaCl, 2.2 g KCl, 0.3 g CaCl.sub.2.2H.sub.2O and 1.2 g NaHCO.sub.3 and adjusting the pH to 6.3 with concentrated HCl. Sodium acetate buffer is used with a pH of 5.0 at 0.93 M/1.25× concentrated Small Intestine Electrolyte Solution (SIES) with a density of 1.09275 g/ml is prepared by adding 125 g NaCl, 15 g KCl and 7.5 g CaCl.sub.2.2H.sub.2O and adjusting the pH to 7 with concentrated NaOH. Intestinal protease inhibitor solution contains trypsin and chymotrypsin inhibitor (Glycine max, SIGMA, T9777) dissolved in milliQ water at 0.58 mg/ml. 2 ml is used per intestinal sample. Hydrochloric acid (Merck, Substrate A) is used at 0.25M. NaHCO.sub.3/NaOH solution (Substrate B) is prepared by dissolving 84 g NaHCO.sub.3 and 40 g NaOH.

(13) Fresh Working Solutions are Prepared as Follows.

(14) 50 ml Saliva is prepared by adding 30 mg α-amylase (Sigma A-6211) to 50 ml saliva electrolyte of which 5.8 ml is added into each reactor before inoculation. 300 ml gastric juice is prepared by adding 15 ml gastric electrolyte concentrated stock and 3 ml 1M sodium acetate buffer pH=5.0 to 282 ml demi-water of which 12.3 ml is needed per reactor. Solution is cooled on ice and enzymes are added when temperature reaches a temperature of below 8° C. Next, add 37.5 mg Lipase DF Amano 15 and 15 mg Pepsin (Sigma P7012-109) and mix for 10 minutes. Store on ice. 500 ml Intestinal Juice is prepared by adding 2.5 g bile extract porcine powder (Sigma) to 250 ml while gradually dissolving in 250 ml cold demi-water and dissolving in 150 ml of cold demi-water of 7.5 g pancreatin (Pfizer) and combining 115 ml cold demi-water with 250 ml Bile solution and 125 ml Pancreatin solution with 10 ml SIES concentrated stock to a total of 500 ml. During the experiment, the solution is kept on ice and mixed continuously. 31.5 ml is used per reactor.

(15) Apparatus and Testing of Samples

(16) Test products of Example 1 are placed into the Multifermentor fed-batch (DasGip) reactors and the apparatus is operated according to the manufacturer's instructions. Magnetic stirring is used at 200 rpm to mix acid and enzymes during digestion. Briefly, 38 ml test sample is added to the reactors and at distinct sample time points (from t=0 minutes to t=130 minutes) a predetermined amount of sample (3 ml at t=0 and 2 ml at following time points) is extracted, snap frozen and stored for further analysis by SDS PAGE and quantification of the amount of signal from distinct protein bands.

(17) Solution Injection Scheme

(18) TABLE-US-00001 SIM Lapsed sample Sample time time pH point vol. Remarks 00:00 0 6.8  0 3 ml 00:05 5 6.8 — — Start addition of gastric juice 00:15 15  10′ 2 ml 00:25 25 6.5 — — 00:35 35  30′ 2 ml 00:45 45 6.2 — — 01:05 65 5.8  60′ 2 ml 01:35 95 5.0  90′ 2 ml 02:05 125 4.3 120′ 2 ml Stop addition of gastric juice 02:10 130 5.4 — — 02:15 135 6.5 — — Start addition of intestinal juice 02:17 137 122′ 2 ml 02:21 141 6.7 126′ 2 ml 02:25 145 130′ 2 ml

(19) Gastric juice is injected with a flow of 40.25 ml/h for 3 minutes from SIM time point 00:05:01 to 00:08:01, followed by injection at 5.25 ml/h until 2:04:59. Intestinal juice is injected with a flow of 80.5 ml/h for 9 minutes from SIM time point 2:15:00 to 2:23:59, followed by injection at 10.5 ml/h for the remainder of the test. First column indicates the SIM time as used by the SIM machine. Second column indicates lapsed time during the experiment. Time points in the fourth column (sample point) correspond to the time indicated in FIG. 2 and takes adaptation of the system to injection of solutions into account. The gastric phase runs from sample points t=0 up to t=120. The intestinal phase runs from sample point t=122 up to t=130.

(20) Following such an established protocol allows mimicking of milk protein digestion kinetics contained in infant formulae in a representative manner.

(21) It was observed that the whey protein fraction, as obtained according to the process of Example 1, displayed a slower protein digestion kinetic than the commercially available infant formula as tested. Fast digestion kinetics, similar to the commercially available infant formula, were observed when the whey protein fraction obtained via the process of example 1 was subjected to a heat treatment, such as a treatment wherein the WPC70 was subjected for 10 minutes to 80° C. It was also observed that the presence of fat in the infant formula did not interfere with the slowed, improved whey protein digestion kinetics since similar results were obtained with or without the presence of fat in the tested composition.

(22) Since it is known that slower protein digestion is beneficial for infants and occurring in human milk compared to commercially available infant formula, it is desirable to produce infant formula of which at least the protein fraction, in particular the whey proteins contained therein, show a digestion kinetic that more closely resembles human milk digestion.