DAIRY PRODUCT AND PROCESS

Abstract

The invention relates to a liquid nutritional composition comprising (a) 2-25% by weight of a calcium-depleted milk protein concentrate (MPC) that has undergone a heat treatment to at least 80 C. and has between 15-45% by weight of the calcium removed; (b) 0-30% by weight fat; (c) 5-45% by weight carbohydrate; wherein the nutritional composition has a viscosity of less than 200 cP at a temperature of 20 C. and shear rate of 100s.sup.1, and has an energy density of at least 0.5 kcal/ml, and wherein protein provides 10-40% of the total energy content of the composition. Also provided is a powdered composition dispersible in water to form the liquid composition.

Claims

1. A method for formulating a liquid nutritional composition comprising (a) preparing a heat-treated calcium-depleted milk protein concentrate (MPC), said preparation comprising calcium depleting an MPC by 15-45% by weight of the calcium and heating the calcium-depleted MPC to at least 80 C. for 1 second to 20 minutes; (b) dispersing 4-20% by weight of the heat-treated calcium-depleted MPC in water optionally with fat and with carbohydrate, to produce a liquid nutritional composition with 0-30% by weight fat and 5-45% by weight carbohydrate; (c) heating the liquid nutritional composition to a temperature above 100 C. to inhibit microbiological activity; wherein the liquid nutritional composition has a viscosity of less than 200 cP at a temperature of 20 C. and shear rate of 100 s.sup.1; and wherein the liquid nutritional composition has an energy density of at least 0.5 kcal/ml, and wherein protein provides 10-40% of the total energy content of the liquid nutritional composition.

2. The method as claimed in claim 1, wherein in step (a), said preparation comprises heating the calcium-depleted MPC at 80-140 C.

3. The method as claimed in claim 1, wherein in step (a), said preparation comprises heating the calcium-depleted MPC prior to the calcium-depleted MPC being evaporated and dried.

4. The method as claimed in claim 1, wherein in step (c), the liquid nutritional composition is ultra-high heat treated (UHT).

5. The method as claimed in claim 1, wherein in step (c), the liquid nutritional compositions is heated at 140 C.-150 C. for 2-5 seconds or at 120 C.-130 C. for 10-20 minutes.

6. The method as claimed in claim 1, wherein the liquid nutrition composition comprises 4-15% by weight heat-treated calcium-depleted MPC.

7. The method as claimed in claim 1, wherein the liquid nutritional composition comprises 5-25% by weight of fat.

8. The method as claimed in claim 1, wherein the liquid nutritional composition comprises 5-15% by weight of fat.

9. The method as claimed in claim 1, wherein the carbohydrate content is 5-40% by weight.

10. The method as claimed in claim 1, wherein the carbohydrate content is 10-35% by weight.

11. The method as claimed in claim 1, wherein the calcium depletion of the MPC has is by cation exchange with monovalent cations of potassium or sodium.

12. The method as claimed in claim 1, wherein 25-40% by weight of the depleted calcium has been replaced with potassium or sodium in the calcium-depleted MPC.

13. The method as claimed in claim 1, wherein 25-35% by weight of the depleted calcium has been replaced with potassium or sodium in the calcium-depleted MPC.

14. The method as claimed in claim 1, wherein the calcium-depleted MPC comprises at least 70% by weight protein on a moisture and fat-free basis.

15. The method as claimed in claim 1, wherein the energy density is at least 1.5 kcal/ml.

16. The method as claimed in claim 1, wherein the energy density is at least 1.5 kcal/ml, and protein provides 10-30% of the total energy content of the liquid nutritional composition.

17. A method for formulating a spray dried composition comprising the method as claimed in claim 1 followed by spray drying the liquid nutritional composition.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0063] FIG. 1 shows the heat stability (as determined by aggregration/coagulation time in minutes) of standard MPC (.square-solid.) and Low Viscosity MPC (.diamond-solid.)(at 140 C.) at pH values in the range 6.3-7.1.

EXAMPLES

[0064] The following examples further illustrate practice of the invention.

[0065] Materials used in the following experiments are coded according to the detail below.

[0066] Standard MPC (MPC 4850, Fonterra Co-operative Group Ltd., Auckland, New Zealand) MPC from this invention (Low Viscosity MPC, Fonterra Co-operative Group Ltd., Palmerston North, New Zealand). The compositions of the MPC ingredients are summarised in Table 1.

[0067] Corn Oilsupplied by NZ Bakels Ltd., Auckland, New Zealand

[0068] Lecithinsupplied as Topcithin NGM Liquid soy lecithinby Cargill, Incorporated Minneapolis, Minn., United States

[0069] Maltodextrinsupplied as MALTRIN M180 (Dextrose Equivalent 18.5)Grain Processing Corporation, Iowa, USA.

[0070] Sucrosesupplied as Chelsea Extra Fine SugarManufacturer: NZ Sugar Co Ltd., Auckland, New Zealand.

TABLE-US-00001 TABLE 1 Summary of Composition of MPCs used Material Standard MPC Low Viscosity MPC Protein (%) 83 83 Calcium (%) 2.2 1.5 Sodium (%) 0.08 1.0

Example 1 Heat Stability of Low Viscosity MPC in Aqueous Solution

[0071] Three batches of 35%-calcium depleted MPC retentate were prepared as described in U.S. Pat. No. 7,157,108 and designated Low-viscosity MPC85. In each case, the calcium depleted MPC retentate was heat treated at a temperature/time combination of 90 C./4 s and then evaporated and dried to produce Low-viscosity MPC85 ingredient which was used in all the examples.

[0072] A 5% protein solution of either standard or the Low-viscosity MPC85 powder was stirred at 60 C. and left to hydrate for 30 minutes. The solution was sub-sampled in 30 mL batches and pH adjusted in the range 6.3-7.1. For heat stability testing, 1 mL aliquots of the pH adjusted solutions were transferred to glass tubes. The glass tubes were placed in an oil bath at 140 C. and visually observed for aggregation and/or coagulation.

Material/Apparatus

[0073] Water bath controlled at 601 C.
Stainless steel beakers (500 mL)
Mechanical stirrers and blades
Weighing boats or small beakers
A timer
Transfer pipettes
Analytical balance weighing to 4 decimal places
1-200 L, 1 mL, and 10 mL pipettes
Magnetic stirrers
pH meter
50 mL sample jars

Reagents 1M HCl & 1M NaOH

[0074] Oil bath at 140 C. for heat stability testing
8 mL heat resistant glass sample tubes
Heatproof gloves or tongs for handling

Procedure

[0075] 1. A water bath was preheated to 60 C. [0076] 2. The weight of a stainless steel beaker was weighed and recorded. [0077] 3. Weigh in the required amount of demineralised water for a 5% protein solution totalling 400 g. [0078] 4. A beaker was placed into water bath under an overhead stirrer and the contents allowed to warm to 60 C. [0079] 5. 24 g of protein powder was weighed (taking into account total % protein in powder) for a 5% protein solution totalling 400 g. [0080] 6. The water was stirred to a deep vortex and the powder slowly added. [0081] 7. Once all the powder had been added, the mixing speed was slowed down and the mixture allowed to hydrate for 30 mins. [0082] 8. The stirrer was stopped and the beaker and contents were reweighed after the 30 min hydration. The solution was topped up to 400 g using RO water and mixed thoroughly. 30 mL aliquots of the solution were sub-sampled into sample containers. [0083] 9. Each sample was pH adjusted in the range 6.3-7.1 using 1M HCl or NaOH with constant stirring. The oil bath was preheated to 140 C. [0084] 10. 1 mL of each sample was transferred into a clear glass tube for heat stability testing. Care was taken to ensure that the samples did not touch the walls of the sample jar and were placed directly on the bottom. [0085] 11. The samples in the oil bath were held at 140 C. using the shaker. As soon as the samples were placed in the oil bath the timer and the shaker were started. [0086] 12. The samples were observed visually and the time for aggregation/coagulation of the sample recorded.

[0087] The results are shown in FIG. 1 and show that the Low Viscosity MPC had greater stability to high temperatures at the pHs tested than the non inventive control.

Example 2: Performance of Low Viscosity MPC in a Model FormulationUHT Process

[0088] Three batches of the model nutritional formulation were prepared according to the method detailed below, using the three samples of the Low-viscosity MPC85 powder described in Example 1 and these were designated Trials 1, 2 & 3.

1. 60 C. demineralised water (36 kg) was weighed into the jacketed mixing vessel
2. Protein powder (7.1 kg Low-viscosity MPC85) was added into continuously stirred water and hydrated for 60 minutes whilst stirring continuously.
3. Carbohydrate blend (18.2 kg) comprising maltodextrin (5.7 kg) and sucrose (12.5 kg) was added and mixed.
4. The mineral blend including potassium chloride (56.6 g), potassium citrate (271.9 g), magnesium chloride (126.8 g) and calcium phosphate (4.6 g) was pre-dissolved in a small amount of water. The mineral solution was then added to the ingredients in the jacketed mixing vessel and mixed.
5. The vegetable oil (5.5 kg) was heated in a separate container to 60 C. The soy lecithin (91 g) was warmed and then added to the oil and this mixture was transferred to the other ingredients already in the jacketed mixing vessel followed by mixing for 5 min.
6. The prepared mixture in the jacketed mixing vessel was passed through a two-stage homogeniser (200/50 Bar).
7. The homogenised mixture was cooled to 25 C. and the pH adjusted to target pH 6.8 with KOH.
8. The mixture was UHT processed at about 145 C. for 4 or 5 sec at a product flow rate of 1201/hr and then packed aseptically. The preheating temperature was between 83-85 C. and achieved using a plate heat exchanger. The product was held for 30 seconds at this temperature. The final heat treatment temperature was then raised to 144-145 C. using direct steam injection. After the holding tube, the first stage of cooling was to 86-87 C. using a flash vessel and the final cooling was to about 24-25 C. using a plate heat exchanger. The product was immediately packed at about 24-25 C. into 250 mL glass bottles and capped.
9. The viscosity, pH and particle size of the final product were measured within 7 days of the UHT heat treatment. The remaining samples were placed into storage at 30 C. for several months and evaluated at 1, 3, 6 & 9 months. Viscosity was measured at 20 C. at 100 s.sup.1 using Anton Paar Physica MCR301 rheometer fitted with cup and bob. The results of the tests are summarised in Table 2. The pH was measured using standard methods at 20 C. and the mean particle size (characterised by [D4,3]) was determined by laser diffraction using a Malvern particle size analyser (Mastersizer 2000, Malvern Instruments Ltd, Malvern, United Kingdom).

[0089] The viscosity results are compared in Table 2. The results show that after heat treatment the viscosities were less than 75 cP at 20 C. for the 3 repeated trials.

TABLE-US-00002 TABLE 2 Results of storage of UHT treated samples held at 30 C. Initial 1 Month 3 Months 6 Months 9 Months pH Trial 1 6.81 6.72 6.71 6.59 6.53 Trial 2 6.82 6.71 6.70 6.59 6.53 Trial 3 6.83 6.72 6.71 6.60 6.54 Viscosity (cP) Trial 1 55 55 58 61 62 Trial 2 56 57 58 63 65 Trial 3 62 63 63 69 73 Mean particle size [D4, 3] (m) Trial 1 1.5 1.0 0.6 0.77 0.99 Trial 2 0.55 0.49 0.50 0.56 0.51 Trial 3 0.58 0.64 0.60 0.58 0.60

[0090] After 9 months storage at 30 C. the cream and sedimentation layers were assessed visually as being slight. All samples were commercially acceptable.

Example 3 Performance of Low Viscosity MPC in a Model FormulationRetort Process

[0091] Three samples of the model nutritional formulation were again prepared from the batches of Low viscosity MPC85 powder described above. In this example, steps 1-7 and 9 were as in Example 2 except that after homogenisation at step 7, the samples were packed into 210 mL cans were filled and sealed. Step 8 used retorting instead of UHT as the heat treatment. In the retort the sterilisation treatment of the filled cans was 121 C. for 10 minutes. The retort used a pressurised steam heat treatment followed by full immersion water cooling to 50 C., then cooling was completed by ambient storage.

[0092] The results of the tests are summarised in Table 3. They show that after heat treatment the viscosities were less than 120 cP at 20 C. for the 3 repeated trials.

TABLE-US-00003 TABLE 3 Results of storage of retorted samples held at 30 C. Initial 1 Month 3 Months 6 Months 9 Months pH Trial 1 6.69 6.55 6.40 6.41 Trial 2 6.66 6.51 6.40 6.39 Trial 3 6.64 6.55 6.41 6.39 Viscosity (cP) Trial 1 98 115 126 Trial 2 103 115 132 Trial 3 114 114 141 Mean particle size [D4, 3] (m) Trial 1 0.87 0.90 Trial 2 0.82 0.81 Trial 3 0.77 0.88

[0093] After 9 months storage at 30 C. the cream and sedimentation layers were assessed visually as being slight. All samples were commercially acceptable.

[0094] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0095] In this specification, percentages are on a by weight basis, unless the context indicates otherwise.

[0096] It is not the intention to limit the scope of the invention to the abovementioned examples only. As would be appreciated by a skilled person in the art, many variations are possible without departing from the scope of the invention. For example, the percentage protein and the calcium-depletion of the MPC can be varied, as can the nature and proportions of the other components of the nutritional composition.