DAIRY PRODUCT AND PROCESS

Abstract

A method for preparing a modified whey protein concentrate (WPC) or whey protein isolate (WPI) is described. It involves (a) providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of 4.7-8.5; (b) heat treating the solution to more than 50 DEG C., for a time that allows protein denaturation to occur; the heat treating comprising heating the solution while under conditions of turbulent flow. At the end of the heat treatment, the heat treated material may be promptly transferred to a drier or to be mixed with other ingredients. The heat-treated WPC or WPI is not subjected to a mechanical shear process prior to the transfer other than where liquid is converted into droplets to facilitate drying. The modified WPC is useful in the manufacture of food and drinks where a high protein content is desired without undesirable changes in texture.

Claims

1.-35. (canceled)

36. A method for preparing a mixture comprising a liquid whey protein concentrate (WPC) or whey protein isolate (WPI), comprising: (a) providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of between 5.5 and 8.5; (b) pressurizing the provided aqueous solution into a flow path; (c) heat treating the pressurized solution to more than 50 C., for a time that allows protein denaturation to occur, said time being less than about 120 s; the heat treating comprising heating the solution while under conditions of turbulent flow with a Reynold's number of at least 500 and wherein the volume weighted mean particle size D[4,3] of the whey protein particles in the pressurized solution is less than about 10 m and the pressurized solution is not subjected to a mechanical shear process to break up particles within the solution; and (d) at the end of the heat treatment, either (i) transferring the heat treated material directly to a mixer to be mixed with at least one other ingredients, including at least one of the group consisting of milk, skim milk, fat, a carbohydrate, milk retentate, or skim milk retentate, or (ii) transferring the heat treated material promptly to a drier and drying the heat treated WPC or WPI; wherein the heat-treated WPC or WPI is not subjected to a mechanical shear process to break up particles within the solution prior to either the optional drying step or the optional mixing step other than a mechanical shear wherein liquid is converted into droplets to facilitate drying.

37. The method as claimed in claim 36, wherein at the end of the heat treatment, the heat treated material is transferred directly to a drier.

38. The method as claimed in claim 36, wherein at the end of the heat treatment, the heat treated material is directly transferred either to a drier to be dried or to a mixer to be mixed with other ingredients; and wherein the heat treated WPC or WPI is not subjected to particle size reduction prior to step (d).

39. The method as claimed in claim 36, wherein at the end of the heat treatment, the heat treated material is promptly transferred to a drier; and wherein the heat-treated WPC or WPI is not subjected to a mechanical shear process prior to drying other than where liquid is converted into droplets to facilitate drying.

40. The method as claimed in claim 36, wherein at the end of the heat treatment, the heat treated material is directly transferred to a mixer to be mixed with at least one other ingredients, including at least one of the group consisting of milk, skim milk, fat, a carbohydrate, milk retentate, or skim milk retentate, wherein the heat-treated WPC or WPI is not subjected to a mechanical shear process prior to mixing with other ingredients.

41. The method as claimed in claim 36, wherein the pH of the WPC solution prior to heating is adjusted to between 5.0 and 8.5.

42. The method as claimed in claim 36, wherein the protein concentration of the WPC solution prior to heating is 16-40%.

43. The method as claimed in claim 36, wherein the heat treating occurs as the WPC or WPI solution passes along a heated flow path with an inside diameter greater than 5 mm and less than 150 mm.

44. The method as claimed in claim 36, wherein the solution passes along a heated flow path and exits at a temperature between 60 C. and 110 C.

45. A method of increasing the protein content of a foodstuff by including a WPC or WPI prepared by the method of claim 36 in the ingredients of the foodstuff.

46. The method as claimed in claim 45 wherein the foodstuff is a snack bar prepared by a method comprising melting fat, if melting is required, and mixing fat or oil with carbohydrate and WPC and allowing the mixture to set.

47. A method of preparing a yoghurt comprising including a dried WPC or WPI prepared by the method as claimed in claim 36 as an ingredient in yoghurt.

48. The method as claimed in claim 47 comprising preparing a yoghurt milk having at least 7% (w/v) protein by mixing the dried WPC or WPI with a milk comprising casein, and acidifying the yoghurt milk to a pH of 3.8-5.5.

49. A method of preparing a yoghurt drink comprising 1.5-15% (w/v) protein comprising mixing a dried WPC or WPI prepared by the method as claimed in claim 36 with a milk comprising casein, and acidifying to a pH of 3.8-5.5.

50. A method for preparing a whey protein hydrolysate comprising preparing a heat-treated WPC or WPI by the method as claimed in claim 36 and contacting the heat-treated WPC or WPI with a protease.

51. A method for preparing a processed cheese comprising: preparing a whey protein ingredient by a method as claimed in claim 36; mixing the ingredient with other ingredients including cheese and water; cooking to form a molten processed cheese; and allowing to cool.

52. A method for preparing a dried modified WPC or WPI with 50-95% of the total solids as whey protein, comprising: (a) preparing an aqueous WPC or WPI having 15-50% (w/v) whey protein at a pH of between 5.5 and 8.5; (b) using a high pressure pump to feed the protein concentrate at a pressure of between 3 to 1000 bars into a high pressure heater, the flow of the product is such that a turbulent flow is effected with a Reynolds number of at least 500; (c) heat treating the solution while the turbulent flow is effected to more than 70 C. for a time that allows protein denaturation to occur, said time being less than about 120 s, and wherein the pressurized protein concentrate is not subjected to a mechanical shear process to break up particles within the solution; (d) at the end of the heat treatment, promptly transferring the heat-treated material to a drier; and (e) drying the heat-treated WPC or WPI, wherein the volume weighted mean particle size D[4,3] of the whey protein particles in the treated WPC stream from the heat treatment arrangement (c) is less than about 10 m and the particles are not subject to a particle size reduction procedure prior to drying.

53. The method as claimed in claim 52 wherein the heat treatment of step (c) occurs in a zone which is coupled directly to the inlet of the drier.

54. A method as claimed in claim 52, wherein the drying is by spray drying.

55. The method as claimed in claim 52, wherein the turbulent flow has a Reynolds number in the range 2,000-50,000.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] FIG. 1 shows a schematic layout of the whey protein heater-reactor system

[0075] FIG. 2 reveals the relationship between apparent viscosity and combinations of holding time and treatment temperature for 27% whey protein feedstock

[0076] FIG. 3 shows the relationship between bar hardness (model nutrition bar samples prepared using samples of dried ingredient from the inventive process and the particle size of the ingredient samples D[4,3] (m).

[0077] FIG. 4 shows the relationship between model nutrition bar hardness (as measured by penetration force) and the particle size distribution of the slurry stream prior to drying as represented by D[4,3] (m).

[0078] FIG. 5 shows bar texture expressed as penetration force versus heating temperature and holding tube time (s) and perceived grittiness in informal sensory (proportional to bubble size).

[0079] FIG. 6 shows a scheme for the process for making yoghurts.

[0080] FIG. 7 shows a schematic diagram of the High Protein Drinking Yoghurt Manufacture Process.

[0081] FIG. 8 shows the viscosity in cP@100 s.sup.1 for the Modified WPC before heating. Modified WPC after heating, Control WPC before heating and Control WPC after heating (from left to right).

[0082] FIG. 9 shows photos of a nutritional food formulation before (I) or after (II) heating. A=formulation containing standard WPC; B=formulation containing modified WPC; H=heated.

[0083] FIG. 10 shows particle sizes prepared ex the tubular reactor.

[0084] FIG. 11 shows a graph of percentage denaturation versus exit temperature at different holding times

EXAMPLES

[0085] The following experiments further illustrate the practice of the invention.

Example 1

[0086] Fresh cheese whey was prepared using standard commercial ultrafiltration/diafiltration techniques to produce a retentate of about 20% total solids, of which 83% was protein. This concentrate stream was then adjusted to pH 6.9 using dilute NaOH and then further concentrated to about 33% solids using a falling film evaporator to produce a concentrate with an exit temperature of 45 C.

[0087] The warm concentrate (27% w/w protein) was fed at a flow rate of 6.3 m.sup.3/h to two high pressure steam heated shell and tube heat exchangers in series using a high pressure pump with a delivery pressure of 250-300 bar. The concentrate exits the first high pressure heater (length 60 m) at 70 C. and exits the second high pressure heater at 80 C. The heater exchangers have a combined length of 120 in with an internal pipe diameter of 18.85 mm. The steam pressure supplied to the first heater was 0.6 bar (g) and the second heater pressure was 0.96 bar (g). The high pressure tubing was Schedule 80 rated, 316 alloy stainless steel pipe.

[0088] After emerging from the second heater, the heat treated concentrate passed through an experimental holding period of either 0 s (no tube section), 45 s (54.8 m), or 90 s (107.3 m) of 24 mm diameter pipe. Following the variable duration holding section, the heat treated concentrate was transported to the nozzle bank at the top of the spray drier; this section of pipe was about 56 m in length with an internal diameter of about 24 mm and provided a further residence time of about 23 s. Thus the high pressure pump delivered the protein concentrate stream through the heaters and holding tube (if present) to the drier without the additional need for a mechanical shear inducing device post the heaterreactor system and prior to spray drying.

[0089] At the spray drier, the heat-treated concentrate was delivered to a bank of 8 nozzles and was atomised into a droplet spray at a pressure greater than 200 bar. An inlet air temperature of 210 C. and a chamber outlet temperature of about 83 C. was used. The powder was further dried and then cooled in a vibrating fluidised bed prior to sifting and packaging of the material to produce a powder of about 3.5% moisture with a bulk density of about 037 g/mL.

[0090] FIG. 1 shows a schematic layout of the whey protein heater-reactor system. The points at which the system pressures were monitored are shown (DP1, DP2 & DP3).

[0091] Wet and dry stream (product) particle sizes and particle size distributions (PSD) were determined using standard techniques and were conducted using a laser diffraction particle size analyser, Mastersizer 2000, Malvern Instruments Ltd, Malvern, United Kingdom.

[0092] Samples of nutrition bars (batches of 1-2 kg) were prepared and evaluated for hardness using a model recipe. The recipe comprised 37.3% heat treated WPC of this invention (or a control using undenatured WPC392, Fonterra), 34.4% glucose syrup Penford A2150, 17.2% glycerine (Bronson & Jacobs Australia and supplied by Bronson & Jacobs NZ), 2.9% Maltodextrin, MALTRIN M180, DE 23-27, (GPC Grain Processing Co. USA and supplied by Salkat NZ) 5.1% palm kernel oil hydrogenated (Premium Vegetable Oils, Malaysia and supplied by Kauri NZ, Wellington), 0.5% lecithin (Cargill International and supplied by Bronson & Jacobs NZ), 2.6% water (w/w). The fat was weighed into a saucepan and melted on a hot plate at a temperature <40 C. The glucose syrup, glycerine, water and lecithin were weighed into a pot and heated to 55 C. on the hot plate. [0093] The protein powder and the corn syrup solids were weighed and dry-blended together. [0094] The liquids and the melted fat were then added to the powders and mixed at 50 rpm using a BEAR mixer (Varimixer, 17584 BMS, Baker Perkins NZ) for 1 min. The mixer was stopped and the sides of the bowl were scraped down. The mixture was mixed for a further 30 s until well combined. [0095] The dough that was formed was then placed in a bar frame (dimension 600 mm330 mm16 mm), covered with plastic film and rolled into shape, to fit the frame. It was then left to set overnight at ambient temperature. [0096] The set dough was then cut into bars of approximately 100 mm30 mm16 mm for the storage trial, to give 66 bars in total. The bars were placed in foil bags, heat sealed, labelled and stored for week at 20 C. before evaluation.

[0097] FIG. 2 reveals the relationship between apparent viscosity and combinations of holding time and treatment temperature for 27% whey protein feedstock. It is known in the art that the denaturation of whey proteins by heat progresses sequentially via a chain of processes to ultimately yield insoluble aggregates that if allowed to reach a few tens of micrometre in size have a gritty texture in the mouth. FIG. 2 reveals that when the heat denaturation was conducted at very high protein concentrations (%), the process could be surprisingly controlled to reveal a novel set of products at temperatures in the range 65-80 C. with holding time of order 1 minute or less, and a further set of novel products at temperatures in excess of 80 C. and holding times less than about 120 s. Without being bound by theory, the higher temperature (second) set of products are likely to be associated with the formation of insoluble aggregates or colloidal particles of increasing size as the heat treatment conditions progress further. (Note that an additional holding time of about 23 s occurs after the experimental holding time in FIG. 2, to convey the fluid into the drier.)

[0098] FIG. 3 shows the relationship between bar hardness (model nutrition bar samples, after one week, prepared using samples of dried ingredient from the inventive process) and the volume weighted mean particle size of the ingredient samples D[4,3] (m). As a separate variable, the points plotted on the figure represent the sensory texture (graininess score) of the bar samples as given by the size of the circles. (The graininess score was determined by informal sensory using a scale 1-9, where 1smooth, 3powdery, 6sandy & 8grainy.)

[0099] Texture analysis was performed using a TA.HDplus Texture Analyser from Stable Micro Systems, Godalming, England.

[0100] The texture measurements were performed by compression. Forces were measured against a set distance (mm). A 5 mm stainless steel cylindrical probe was pushed into the bar at a constant rate of 1 mm/s to a compression depth of 12 mm, and was then withdrawn at a rate of 10 mm/s.

[0101] Where possible, three compressions were made over the surface of each bar sample. Two bars were evaluated for each dairy protein powder. The samples were removed from 20 C. storage and texture measurements were made at room temperature.

[0102] Surprisingly and considering the art of products prepared using homogenisation, FIG. 3 reveals that there were a set of process conditions wherein it was possible to produce coarse heat aggregated whey protein particles e.g. >100 m that were not gritty in the mouth in a nutrition bar application without homogenization following or during the heat treatment and before drying. The process conditions required to prepare this advantageous ingredient were then examined more closely.

[0103] FIG. 4 shows the relationship between model nutrition bar hardness (as measured by penetration force) and the particle size distribution of the slurry stream prior to drying as represented by D[4,3]. The secondary variable plotted in FIG. 4 is the grittiness score of the bar samples as indicated by the size of the circle. Generally, FIG. 4 shows that softer bars' result from larger colloidal particles which might generally be expected to be the result of more extensive heat treatments. However, FIG. 4 indicates that there exists a novel set of conditions where an ingredient can be prepared (after drying) from coarse particles that do not result in grittiness in the mouth as expected from prior art whey protein aggregates of similar size.

[0104] Bar texture expressed as penetration force versus heating temperature and holding tube time (s) and perceived grittiness in informal sensory (proportional to bubble size). The control was a bar sample prepared using an unheat-treated (native) whey protein powder, WPC392 (Control 392), Fonterra Co-operative Group Limited, Auckland.

[0105] Notes:

[0106] Table 1 d shows that when the various sets of data are combined (Tables 1a, 1b & 1c), it is revealed surprisingly that there is a set of optimal conditions for preparation of the denatured whey protein ingredient with unique properties for nutrition bar applications of <45 s seconds holding time and a final heater temperature of 80-85 C., using the present heater design.

Example 2

[0107] The inventive protein ingredient was prepared using the method previously disclosed using a whey protein feed stream containing approximately 80% protein on a solids basis and a solids concentration of 32%, a processing flow rate of 6.4 m.sup.3/h, a high pressure preheater outlet temperature of 58 C., a final high pressure heater outlet temperature of 80 C. and a residence time from the heater exit to the dryer of 23 seconds i.e. 0 s holding tube plant configuration.

[0108] Trials were carried out to establish the texture and sensory properties of high protein yoghurt using either the inventive heat denatured whey protein ingredient or a commercial native cheese whey WPC392 (Fonterra Co-operative Group Limited, Auckland, New Zealand) as alternative sources of protein fortification. These yoghurts will be compared to a standard 4.5% protein yoghurt (3.5% protein from skim milk, 1.0% protein from SMP top-up).

[0109] Initial yoghurt trials were carried out using the ingredient of this invention and WPC392 at high levels of addition (10-15% protein yoghurts) to determine baseline textural properties. When the yoghurt milks were heated using the standard heat treatment (95 C./8 min), the milks containing WPC392 curdled and formed weak gels, and could not be further processed. Surprisingly, the protein ingredient of this invention did not gel and was able to be used to prepare a high protein yoghurt.

[0110] In other trials where WPC392 was used, it was added after the heat treatment step to reduce the potential for the added whey protein to gel.

Experimental Plan/Variables

[0111] Table 2 details the formulations and top-up ingredients for the high protein yoghurts. These are compared with a standard 4.5% protein yoghurt (0% fat) sensory control yoghurt.

TABLE-US-00001 TABLE 2 Experimental plan Addition Fat Protein Protein point of content content from top-up Top-up top-up Sample (%) (%) Ingredient ingredient ingredient 11 0 15 11.5 Inventive At re- protein combining ingredient 12 0 12 8.5 Inventive At re- protein combining ingredient 13 0 15 10.5/1.0 Inventive At re- protein combining ingredient/ SMP 14 0 12 7.5/1.0 WPC392 At re- combining 15 0 15 11.5 WPC392 After heat treatment 16 0 12 8.5 WPC392 After heat treatment 0% fat 0 4.5 1.0 SMP At re- 4.5% protein combining control

Formulations

[0112] The formulations used are given in Table 3a and the recipes in Table 3b.

TABLE-US-00002 TABLE 3b Recipes used to prepare the samples Trial Number Reference 11 12 13 14 15 16 control Trial condition 15% 12% 15% 12% 15% 12% 0% fat protein protein protein protein protein protein 4.5% using using using using WPC392 WPC392 protein inventive inventive inventive inventive (not heat (not heat ingredient ingredient ingredient Ingredient treated) treated) and SMP Inventive 934.7 691 852.8 609.1 0 0 0 ingredient (g) WPC392 (g) 0 0 0 0 934.7 691 0 Potassium 1.3 1.3 1.3 1.3 1.3 1.3 1.3 sorbate (g) SMP (g) 681.2 681.2 876.2 876.2 681.2 681.2 876.2 Chr. Hansen 13 1.3 1.3 1.3 1.3 1.3 1.3 YF-L702 lactic culture (g) Water (g) 4882 5125 4768 5012 4882 5125 5621 Total (g) 6500 6500 6500 6500 6500 6500 6500

Manufacturing Process

[0113] The ingredients (other than the culture) were dispersed in warm water and allowed to stand for a period to allow proper hydration. The solutions were heated to about 55 C. and then homogenised 150/50 Bar. The samples were then batch heat treated in a water-bath at 90 C. for 10 minutes. The samples were cooled to incubation temperature and the culture added and dispersed.

[0114] Fermentation times were considerably longer for the high protein yoghurts. Incubation was at 38 C. for 15-16 hours. The samples of stirred yoghurt were sheared (smoothed) by pumping through a back pressure valve (BPV) or orifice with a pressure drop of 1.7 Bar and at a temperature of 17 C.

[0115] See Yoghurt Process Diagram FIG. 6.

Results

[0116] A summary of all the trial data is given in Table 4.

TABLE-US-00003 TABLE 4 Summary of trial results Trial Number Reference 11 12 13 14 15 16 control Final fermentation pH 4.65 4.51 4.67 4.57 4.65 4.59 4.66 Protein (TN*6.38) 15.3 11.7 14.8 11.7 14.9 11.9 4.5 Apparent viscosity at 594 274 579 532 370 376 504 50 s.sup.1 Drained syneresis (%) 51 96 12 28 98 97 38 at day 7

Viscosity

[0117] The viscosity of both 15% protein yoghurts (3.5% SMP with 11.5% protein of the inventive protein ingredient and 4.5% SMP with 10.5% of the inventive protein ingredient) were around 590 mPa.Math.s. Surprisingly, the viscosity was similar to a 4.5% protein yoghurt (Table 4). The viscosity of the 12% protein yoghurt (with 3.5% protein SMP base) was also lower than the non-inventive controls.

Syneresis

[0118] The syneresis values of the stirred yoghurts are shown in Table 4.

[0119] The syneresis values of the 12% protein yoghurt (3.5% protein SMP base) and the 2 two yoghurts containing WPC392 were very high (>90%). The inventive 15% protein yoghurt and 12% protein yoghurts (4.5% protein SMP base) were lower or similar to a standard 4.5% protein yoghurt.

Informal Sensory

[0120] The samples were evaluated, informally by 5 members of the cultured foods team. The flavour of the inventive high protein yoghurts were perceived to have less protein flavour than the samples containing WPC392.

Example 3 High Protein Drinking Yoghurt with Low Viscosity

[0121] The inventive protein ingredient was prepared using the method of Example 1 using a whey protein feed stream containing approximately 80% protein on a solids basis and a solids concentration of 32%, a processing flow rate of 6.4 m.sup.3/h, a high pressure preheater outlet temperature of 58 C., a final high pressure heater outlet temperature of 80 C. and a residence time from the heater exit to the dryer of 23 seconds i.e. 0 s holding tube plant configuration.

[0122] Trials were carried out to manufacture high protein drinking yoghurt with viscosity low enough for the final product to be consumed as a beverage.

Experimental Plan/Variables

Formulations

[0123] The recipes are given in Table 1.

TABLE-US-00004 TABLE 5 Recipes for the preparation of the fermented beverage Quantity (g) High protein 4.5% low fat Inventive yoghurt Component beverage (control) Dried denatured, whey protein ingredient of 847 0 this invention Skim milk powder 2239.6 876.2 Sugar 660 0 Cream (40% fat) 660 0 Potassium sorbate 4.4 1.3 Chr Hansen culture YF-L702 0.4 1.3 Water 17589 5621 Total 22,000 6500 Composition % Total protein 6.50 4.5 Fat 1.47 Nil Carbohydrate 8.8 Casein:whey protein (ratio) 43:57 80:20

Manufacturing Process

[0124] The ingredients (other than the culture) were dispersed in warm water and allowed to stand for a period to allow proper hydration. The milk was heated to about 55 C. and 2-stage homogenised 150/50 Bar. The homogenised milk was heated to 95 C. for 8 minutes by circulating in a plate heat exchanger (PEE) then cooled to incubation temperature in a further PHE and finally discharged into small vat. Culture was added and dispersed and the milk was incubated at 42 C. until pH of about 4.6 was reached.

[0125] The incubation time was around 5.5 hours. Despite the high protein content, the fermentation time was surprisingly typical of much lower protein (e.g. 4.6%) yoghurts.

[0126] The high protein drinking yoghurt was cooled to approximately 20 C. by pumping it through a PHE, then sheared (smoothed) by passing it through a back pressure valve (BPV) or orifice with a pressure drop of 3 Bar.

[0127] See diagram of the high protein drinking yoghurt manufacturing process FIG. 2.

Results

[0128] A summary of the trial results is given in Table 6.

TABLE-US-00005 TABLE 6 Summary of trial results Trial Number High Protein Reference control Drinking (0% fat, 4.5% Yoghurt protein, as above) pH at end of fermentation 4.56 4.66 pH at 7 days. 4.46 Protein (TN*6.38) 6.1 4.5 Apparent viscosity at 205 504 50 s.sup.1

Viscosity

[0129] The viscosity of the high protein drinking yoghurt was less than half that of a 4.5% (low fat) skim milk yoghurt control making the product surprisingly suitable as a yoghurt beverage.

Example 4 Preparation of Enzyme Treated Hydrolysates

[0130] A common recipe was used to screen five protein samples: undenatured 80% whey protein concentrate (WPC) [control 1], and three inventive denatured whey proteinates, T13, T14 and T21 and a fully denatured lactalbumin powder [control 2]see below for details.

[0131] Other protein ingredients used were:

Lactalbumin 8254 (control 2), available Fonterra Co-operative Group Limited, Auckland. Lactalbumin 8254 is 100% denatured.
Sodium caseinate 180 available from Fonterra Co-operative Group Limited, Auckland.
Cheese WPC80 (WPC392) available from Fonterra Co-operative Group Limited, Auckland. WPC392 is essentially native whey protein i.e. 0% denatured.

[0132] A range of inventive denatured WPC powders (denaturation >95%) were reacted with Alcalase and Thermoase (together) using the same recipe (1% Alcalase and 1% Thermoase) and known art control whey protein ingredients used for comparison were WPC392 and lactalbumin 8254.

[0133] Details of the hydrolysis recipe are given in Table 7.

TABLE-US-00006 TABLE 7 Recipe used for the enzymatic hydrolysis of the protein ingredient Trial Basis 1000 g Protein ingredient (Total Solids 6%) 60 g Mass Water 940 g Total Enzyme 0.60 g Alcalase 0.60 g Thermoase Subsequently added for pH adjustment: NaOH (diluted 10% w/w) 3.06 g KOH (diluted 10% w/w) 14.57 g 940 g of RO water was heated to 65 C. in a waterbath. 60 g of the protein ingredient was added to the water over 5 min with continuous stirring.

[0134] The pH was adjusted to pH 7.5 using NaOH and KOH if required

[0135] At T=0 min both Alcalase and Thermoase enzymes were added to the solution (pH 7.5 thermostat at 65 C.)

[0136] The pH of the reaction mixture was maintained at 7.5 during the course of the digestion by adding alkali as indicated in Table 3

[0137] The hydrolysis was for 5 hrs total reaction time.

[0138] The reacted solution was heated at 85 C. for 20 min to inactivate the enzymes.

[0139] The molecular weight profile (MWP) was analysed using size-exclusion chromatography using the method disclosed at ANZSMS22 (Australia and New Zealand Society for Mass Spectrometry 22nd annual conference) in Sydney, January 2009.

[0140] The following are trial hydrolysate batches prepared using the dried denatured WPC ingredient of this invention (and a control WPC392). The ingredient of this invention advantageously gave a desired MWP, which is <1% of material in the >20 kDa region. The same recipe (enzyme combination) for hydrolysis of the T13, T14 and T21 powders was used.

[0141] The ingredients of this invention were prepared according to the heat treatment procedures specified below.

T13=85 C. 0 s no supplementary tube holding time
T14=90 C. 0 s supplementary tube holding time
T21=85 C. 45 s supplementary tube holding time

[0142] Details of the recipes are given in Table 8.

TABLE-US-00007 TABLE 8 Recipe used in further hydrolysis trials Trial Basis 1000 g Total Solids 6% 60 g Mass Water 940 g Total Enzyme (2%) 1.2 g NaOH @ 10% w/w 3.06 g KOH @ 10% w/w 14.57 g

[0143] A variety of enzymes, including proteolytic enzymes, are used in the preparation of human nutrition products. Different nations have differing regulations. The European Union appears to be evolving regulations towards lists of specifically approved enzymes. http://www.amfep.org/documents/Amfep%2009%2001%20-%20Amfep%20Statement%20on%20Food%20Enzymes%20Regulation%20-%20FIAP%20-JAN09.pdf

[0144] For the purposes of demonstrating the beneficial and versatile outcomes of the ingredient of this invention when used as a substrate for proteolysis, a selection of enzymes were selected for screening of proteolytic efficacy.

[0145] The enzymes used were supplied by:

Alcalase 2.4LNovozymes Australia Pty. Ltd (www.novozymes.com),
Enzidase TSP Concentrate (TSP)Zymus International Ltd (www.zymus.net),
PancreatinAmerican Laboratories Inc (www.americanlaboratories.com),

Thermoase PC10FDaiwa Kasei K.K. (Shiga, Japan).

[0146] Enzymes TSP and Pancreatin were used individually in substitution of the pair of enzymes used in Table 7 to prepare a further series of hydrolysates according to the details given in Table 9.

TABLE-US-00008 TABLE 9 Details of enzymes and their reaction conditions Dose Enzyme (% wrt Total Solids) Target pH Optimal Temp TSP 2 7.5 55 C. Pancreatin 2 8.0 50 C.

[0147] Table 10 summarises the MWP resulting from the hydrolysates prepared using the Alcalase and Thermoase combination detailed in Table 7.

TABLE-US-00009 TABLE 10 Comparison of denaturation levels and resulting hydrolysed MWPs of reacted samples Level of denaturation MWP Ingredient (%) >20 kDa 5-20 kDa 1-5 kDa <1 kDa WPC392 0 2.96 3.61 25.62 67.81 (Control WPC) T13 96 0.92 1.37 17.56 80.15 T14 94 0.89 1.14 18.49 79.47 T21 99 0.82 1.26 18.11 79.81 Lactalbumin 100 1.21 2.95 30.23 65.62 8254 (Control)

[0148] It is generally desirable that less than 1% of the peptide has a molecular weight >20 kDa in hydrolysates designed for infant formulates where reduced antigenicity claims are made. The ingredient of this invention surprisingly was able to meet this limit without the need for extra treatment steps, thus avoiding the expense and yield loss of subsequent ultrafiltration. Tables 11 and 12 summarise the yield and processing problems typically presented by preparing hydrolysates using known art processes and compares these to the benefits arising from the invention.

TABLE-US-00010 TABLE 11 Comparison of yield advantage of inventive ingredient with commercial lactalbumin Denatured WPC of this Lactalbumin 8254 invention Yield loss in There is a significant There was negligible substrate protein (as TN*6.38) yield loss when making manufacture yield loss when making denatured ingredient of conventional lactalbumin. this invention.

TABLE-US-00011 TABLE 12 Comparison of yield advantages of inventive ingredient with existing commercial hydrolysates Hydrolysate made from Potential hydrolysate Lactalbumin from WPC of this invention Yield loss in Hydrolysis of Lactalbumin Hydrolysis of the denatured hydrolysate 8254 under typical hydrolysis ingredient of this invention manufacture conditions produces a allowed the desired MWP hydrolysate with >1% in profile to be prepared the >20 kDa fraction. without ultrafiltration. Further purification can obtain <1% material in the >20 kDa fraction and this step will involve a yield loss.

Hydrolysis of One of the Above Inventive Powders (T13) Using Different Recipes (Enzymes).

[0149] A further series of hydrolysis reactions using the inventive T13 ingredient (96% denatured) and two different recipes (enzymes Pancreatin and TSP) were conducted with the results given in Tables 13 and 14.

TABLE-US-00012 TABLE 13 Results of hydrolysis using Pancreatin enzyme Enzyme (2% dose) Substrate >20 kDa 5-20 kDa 1-5 kDa <1 kDa Pancreatin T13 0.47 1.85 29.70 67.98 Pancreatin Lactalbumin 3.82 2.36 30.42 63.39 8254 Pancreatin WPC392 1.02 1.60 29.49 67.89

[0150] The ingredient of this invention when treated with Pancreatin gave a more preferred MWP that avoided the need for ultrafiltration to remove excess >20 kDa material.

TABLE-US-00013 TABLE 14 Results of hydrolysis using TSP enzyme Enzyme (2% dose) Substrate >20 kDa 5-20 kDa 1-5 kDa <1 kDa TSP T13 0.49 2.03 35.17 62.31 TSP Lactalbumin 2.40 3.01 32.20 62.39 8254 TSP WPC392 1.58 1.37 30.09 66.96

[0151] The ingredient of this invention when treated with TSP gave a more preferred MWP that avoided the need for ultrafiltration to remove excess >20 kDa material.

[0152] Two further hydrolysis reactions were conducted using the inventive protein ingredient but modified to the extent that the protein ingredient was obtained directly following the thermal denaturation procedure of the invention as a liquid inert stream (90% denatured) and before drying, using different recipes (enzymes) and shown in Table 15. Table 15 also summarises the results of hydrolysing the liquid stream ingredient of this invention.

TABLE-US-00014 TABLE 15 Results of hydrolysing the inventive liquid protein stream Enzyme (dose) >20 kDa 5-20 kDa 1-5 kDa <1 kDa Pancreatin (2%) 0.58 2.00 30.46 66.96 Alcalase 2.4 L (2%) 0.22 1.29 32.71 65.79

[0153] The un-dried ingredient version of this invention (liquid stream) again gave a preferred MWP that avoided the cost of drying and the need for subsequent treatment to remove unwanted content >20 kDa.

Example 5 Liquid Nutrition/Beverage/Enteral/Medical Foods Examples

[0154] The following two examples illustrate the use of the inventive whey protein ingredient to prepare model beverages with the special properties useful in a variety of nutritional and medical foods. In one series the beverage had a calorific value of 1 kcal/g. In the second series, the beverage had a calorific value of 1.5 kcal/g.

[0155] For each of the calorific values, three formulations were examined: [0156] a) 95% of the protein heat denatured whey protein powder of this invention and 5% comes from sodium caseinate [0157] b) A replicate of (a) above, [0158] c) A control of 100% heat denatured whey protein powder of this invention and no sodium caseinate.

[0159] 28 kg of 55 C. demineralised water was weighed into the Cowles Dissolver

[0160] Protein added and mixed for 60 minutes

[0161] Maltodextrin and sucrose was added and mixed for 5 minutes

[0162] The minerals were pre-dissolved in 50 C. in a small amount of water and mixed for 5 min

[0163] The mineral solution was added to the ingredients into the Cowles Dissolver and mixed for 5 min

[0164] The solution was warmed further

[0165] The oil and lecithin was warmed to aid dispersion and mixed in a separate container

[0166] The oil-lecithin mixture was added to the Cowles Dissolver solution and thoroughly dispersed

[0167] The dispersed and still warm solution was two-stage homogenised

[0168] The homogenised solution was cooled to 25 C. and the pH adjusted to target pH 6.8 with KOH

[0169] Water was added to the solution to top up as required to give a final weight of 40 kg

[0170] The solution was transferred to the UHT plant and UHT processed at 140 C. for 4 sec using direct steam injection heating packed aseptically into 250 mL glass bottles and capped.

[0171] Various tests were conducted before and after the UHT heat treatment.

1 kcal/g Model Nutritional Foods Type Formulation

[0172] Formulation (a) differed from formulation (b) in that a replicate batch of inventive ingredient was prepared for use. Formulation (c) used the ingredient from the second batch. The formulations are detailed in Table 16.

TABLE-US-00015 TABLE 16 Model formulation and recipes for 1 kcal/g beverage examples Percentage Based Formulations Formulation Formulation Formulation Ingredients (a) (b) (c) Water 75.8% 75.9% 75.9% Heat denatured whey protein 4.6% 4.5% 4.7% ingredient Sodium caseinate 180 0.2% 0.2% 0.0% Sucrose 4.4% 4.4% 4.4% Maltrin M180 maltodextrln 11.1% 11.1% 11.1% Tri-sodium citrate di-hydrate 0.6% 0.6% 0.6% Potassium chloride 0.2% 0.2% 0.2% Tri-potassium citrate 0.1% 0.1% 0.1% monohydrate Magnesium chloride 0.2% 0.2% 0.2% Tri-calcium phosphate 0.3% 0.3% 0.3% Canola oil 2.3% 2.3% 2.3% Lecithin 0.1% 0.1% 0.1% Pilot Plant Trials 40 L beverage Ingredients g g g Water 30336.5 30348.5 30344.9 Heat denatured whey protein 1839.4 1811.2 1894.9 ingredient Sodium caseinate 180 78.9 77.5 0.0 Sucrose 1752.8 1762.8 1756.1 Maltrin M180 maltodextrin 4452.7 4452.2 4454.9 Tri-sodium citrate di-hydrate 251.6 251.7 256.3 Potassium chloride 83.9 83.9 84.0 Tri-potassium citrate 44.9 44.9 44.8 monohydrate Magnesium chloride 74.9 74.9 74.9 Tri-calcium phosphate 123.8 123.8 123.9 Canola oil 906.7 916.9 913.6 Lecithin 53.9 51.7 51.7 Solids sum 9663.5 9651.5 9655.1 % Total Solids 24.2% 24.1% 24.1%
1.5 kcal/g Model Nutritional Foods Type Formulation

[0173] The formulations used for the 1.5 kcal/g evaluations are shown in Table 17.

TABLE-US-00016 TABLE 17 Formulation and recipes for 1.5 kcal/g beverage examples Percentage Based Formulations Formulation Formulation Formulation Ingredients (a) (b) (c) Water 68.80% 68.79% 68.76% Heat denatured whey protein 6.56% 6.51% 6.85% ingredient Sodium caseinate 180 0.29% 0.30% 0.0% Sucrose 5.64% 5.60% 5.62% Maltrin M180 maltodextrin 14.19% 14.28% 14.24% Tri-sodium citrate di-hydrate 0.25% 0.24% 0.26% Sodium chloride 0.22% 0.22% 0.22% Potassium chloride 0.13% 0.11% 0.11% Tri-potassium citrate 0.12% 0.14% 0.14% monohydrate Magnesium chloride 0.20% 0.19% 0.19% Tri-calcium phosphate 0.21% 0.21% 0.21% Canola oil 3.23% 3.25% 3.23% Lecithin 0.16% 0.16% 0.16% Pilot Pilot Trials Ingredients 40 L beverage Water 27518.9 27514.5 27503.7 Heat denatured whey protein 2623.0 2605.2 2739.7 ingredient Sodium caseinate 180 117.4 118.4 0.0 Sucrose 2257.2 2239.5 2246.7 Maltrin M180 maltodextrin 5678.0 5711.9 5697.2 Tri-sodium citrate di-hydrate 98.6 97.0 103.1 Sodium chloride 88.1 88.9 89.4 Potassium chloride 54.0 45.6 45.0 Tri-potassium citrate 48.1 56.1 56.7 monohydrate Magnesium chloride 78.0 77.7 77.7 Tri-calcium phosphate 83.6 83.5 83.6 Canola oil 1292.3 1299.1 1293.0 Lecithin 62.7 62.7 64.3 Solids sum 12481.1 12485.5 12496.3 % Total Solids 31.2% 31.2% 31.2%

[0174] The results of the evaluation of the samples prepared according to the formulations of Tables 16 and 17 are shown in Table 18.

TABLE-US-00017 TABLE 18 Viscosity (cP) Particle Size Run # pH Brookfield D[4, 3] (m) D[3, 2] (m) Table of 1 kcal/mL results Before Formulation 6.83 5.6 0.63 0.24 HT (a) Formulation 6.83 5.6 0.66 0.25 (b) Formulation 6.87 5.2 0.79 0.27 (c) After Formulation 6.82 6.7 1.83 0.33 HT (a) Formulation 6.79 6.8 1.62 0.33 (b) Formulation 6.80 5.9 0.97 0.27 (c) 1.5 kcal/mL Before Formulation 7.04 9.7 0.85 0.27 HT (d) Formulation 6.73 10.6 1.05 0.33 (e) Formulation 6.73 10.4 0.81 0.24 (f) After Formulation 6.98 10.1 1.24 0.37 HT (d) Formulation 6.69 13.3 2.56 0.60 (e) Formulation 6.68 10.0 1.43 0.41 (f)

Example 6 Use of Direct Steam Injection to Produce Heated Liquid Whey Protein Stream in Turbulent Flow Conditions that is Useful as a Protein Ingredient

[0175] A protein concentrate solution was obtained by reconstituting a 25 kg cheese WPC 392 powder in 70 litres of chlorinated water. The WPC powder had 81% protein, 5.7% fat, 3.4% ash, 4% lactose, and 4% moisture. After reconstitution the whey protein solution was continuously mixed at 50 C. for 2 hours to allow complete hydration of the protein.

[0176] The whey protein solution (pH 6.8) was pumped through a pilot plant product line at 152.5 kg/h (137.4 L/h, product density of 1.11 kg/L) where it was heated by direct injection of steam at 170 C. and 7 bar gauge via a steam injection valve. The product line was a 5 m long, 10 mm i.d. stainless steel tube. The steam pressure was adjusted to between 5-7 bar gauge so that the product temperature was maintained at about 90 C. The product flow through the DSI unit had a calculated Reynolds number of 599. The heated liquid was collected via product valve 5 m after the DSI point. It took 3 s for the product to travel from the steam injection point to the collection point. The heated stream was 89.1 C. at the exit of the DSI.

[0177] The heated stream was collected into a container and it became a semisolid paste upon cooling to room temperature. This heated stream was used as a protein and water source in making the model nutritional food formulation shown in the Table 19 below. A sample of the original WPC powder was used in preparation of another sample of the nutritional food formulation as a control.

TABLE-US-00018 TABLE 19 Recipe of a model nutritional formulation Ingredients g Water 197.84 Liquid protein ingredient of this 48.53 invention Sucrose 80.82 Maltrin maltodextrin 37.33 Tri-potassium citrate monohydrate 0.80 Potassium chloride 0.49 Lecithin 0.60 Canola oil 33.60 Total (g) 400.00

[0178] The preparation of the nutritional formulations involved reconstitution of the protein ingredient with water at 55 C. for 30 min using an overhead stirrer. The sucrose, maltrin, and minerals were added while mixing and then the mixing continued for further 10 minutes. The mixture was heated to 70 C. then the oil (with lecithin already dissolved in it by mixing at 70 C.) was added then mixing continued for further 10 min. The mixture was then two-stage homogenised (200/50 bars) using a bench-top homogeniser (NIRO-SOAVI, Panda No. 2638, Niro Group, Parma-Italy). The homogenised formulation was then placed in 10 ml retortable glass bottles then heated at 121 C. for 10 min in an oil bath. The heated samples were cooled immediately to 20 C. in cold water. The viscosities of the homogenised formulations before and after heating were measured using a Paar Physica rheometer (model UDS200, Anton Paar GmbH, Graz, Austria) with a cone and plate geometry, shear sweep 0.1 to 500 s-1, at 20 C.

[0179] FIG. 8 shows the effect of the modified WPC on the viscosity of the model nutritional food formulation before and after heating (121 C., 10 min). The viscosities of both formulations before heating were similar. After heating, the viscosity of the formulation containing modified WPC increased to about 84 cP. The inventive product remained a smooth free flowing drinkable product. However, after heating the control formulation containing standard WPC had formed a gel making the viscosity measurement impossible.

[0180] FIG. 9 shows photographs of the formulations before and after heating. It is clear that the formulation containing modified WPC remained a smooth free flowing liquid while that containing standard WPC formed a gel.

[0181] Nutritional formulations are used as meal replacers for a wide range of consumers to meet various nutritional and/or lifestyle requirements. These foods are aimed to provide the full nutritional requirements in small packs of drink. As such they often contain high fat, carbohydrate, and protein such as those in the model formulation given in Table 19 above. Their processing always involved severe heat treatment (e.g. 121 C. for 10 min) because of the need to be microbiologically safe. In such heat treatment it is important to have robust ingredients that are able to withstand the severe heat treatment conditions without gelling or forming solid lumps. This example demonstrated that using the inventive heat modified WPC of this invention allowed addition of whey protein at high level (>9%) in a nutritional formulation that remained smooth liquid (low viscosity) after its final product heat treatment.

Example 7

[0182] This study was carried out using a Rapid Visco Analyser (RVA 4). A model individually wrapped slice (IWS) processed cheese formulation containing 4% of either cheese whey derived WPC 392 (80% protein) or inventive heat denatured whey protein ingredient was used for the comparison. The firmness and melt of the resulting products were measured along with their composition and microstructure.

Objectives

[0183] To compare the performance of standard whey protein concentrate (WPC) 392 and inventive heat denatured whey protein ingredient by: [0184] 1. Making IWS processed cheese in an RVA using the two whey protein concentrates. [0185] 2. Comparing the properties of the resulting processed cheese samples.

Methods and Materials

[0186] Two processed cheese slice formulations were manufactured in a Rapid Visco Analyser (RVA). A simple model IWS processed cheese formulation was used which contains 4% WPC392 or inventive heat denatured whey protein ingredient. Run 1 contained the standard WPC392 and Run 2, the inventive heat denatured whey protein ingredient. The actual formulations are tabulated in Table 20.

TABLE-US-00019 TABLE 20 Formulations used to prepare samples Sample with inventive Control with WPC392 ingredient Ingredient (g) (g) Rennet casein 3.34 3.34 Added water 10.78 10.78 Tri-sodium citrate 0.72 0.72 Salt 0.33 0.33 High solids cheese 5.97 5.97 (Cheddar) Salted butter 6.83 6.83 WPC392 1.32 NA Inventive ingredient NA 1.32 Lactose 0.47 0.47 Citric acid 0.21 0.21 Potassium sorbate 0.03 0.03 Total weight 30.00 30.00 Analysis % % Moisture 47.3 47.3 Fat 52.7 52.7 Protein 18.3 18.3 Salt 1.8 1.8

[0187] The methods used in this work were taken directly from published PCT patent application WO 2007/108708 A1 (Wiles, Lee, Anema and Havea)

Blending

[0188] Rennet casein, WPC, trisodium citrate, salt and water were mixed together and allowed to hydrate for 40 minutes in an aluminium RVA canister. Grated cheese, salted butter, lactose, citric acid and potassium sorbate were added and mixed in.

Cooking

[0189] The cheese blends were cooked in the RVA for 10 min. The temperature was increased from 25 C. to 87 C. over the first 4 minutes and held for the remaining 6 minutes at 87 C. The stirring speed was increased from 0 to 800 rpm over the first 4 min and held at 800 rpm for the remaining 6 min. On completion of cooking, the hot processed cheese sample was poured onto a polypropylene sheet, covered with another polypropylene sheet, and rolled into a slice. The slice was sealed in a zip-lock plastic bag and quickly cooled on an aluminium tray in a fridge. 6 slices were made for each run. The viscosity was recorded on the RVA immediately prior to forming each slice.

Composition

[0190] Moisture was analysed using a conventional oven method (16 hours at 105 C.). pH was measured using a Radiometer PHM82 Standard pH meter and N48 EE probe.

Texture Measurements

[0191] The slices were held at 5 C. for 3 days prior to testing. For the texture testing, 4 slices were stacked together, cut in half, and the two halves stacked. Thus the test stack was 8 slices thick.

[0192] Firmness was measured using penetrometry ( cylinder [6.4 mm]) on a TA-HD Texture Analyser (aka Cylinder Test) at 13 C. The cylinder was inserted 10 mm into the stack of slices, at a speed of 1 mm s-1 and the peak force was recorded. 4 measurements were taken.

[0193] Stress and strain were measured at 13 C. using a Vane Test (Brookfield 5XHBTDV-II viscometer). A 6 mm, 4-bladed Vane was inserted to a depth of 10 mm, and rotated at 0.5 rpm until the yield point was reached. 4 measurements were recorded.

[0194] Melts were measured using a Schreiber Melt Test (232 C. for 5 min, Zehren and Nusbaum 1992) Process Cheese. Cheese Reporter Publishing Company.

Results

Composition

[0195] The moisture and pH data is shown in Table 21. The moisture and pH of the samples are very consistent. This means that differences in texture and melt properties are likely to be due to differences in ingredient performance rather than compositional variation.

[0196] Evaporation of moisture occurs during the cheese manufacture in the RVA. The moisture was not adjusted for evaporation during processing as this is assumed to be constant between batches. The consistent moisture data in Table 21 confirms this approach.

TABLE-US-00020 TABLE 21 Summary of results Runs Standard WPC392 Inventive ingredient Viscosity Ex-RVA (cP) 1795 1483 Cylinder Force (N) 5.86 6.75 Vane Stress (Pa) 12505.sup. 15020.sup. Strain (rad) 0.797 0.866 Melt test Schreiber 2.3 7.0 Composition Final pH 5.61 5.60 Moisture (%) 46.3 46.6 Results are indicated 1 standard deviation.

Final Viscosity

[0197] The average final viscosities are tabulated in Table 21.

[0198] The final viscosity is clearly different with the processed cheese containing WPC392 higher than that containing inventive heat denatured whey protein ingredient.

Firmness as Measured by the Cylinder Test

[0199] The firmness results are recorded in Table 21. The firmness of the IWS made from standard WPC392 appears to be lower than the IWS made from the inventive heat denatured whey protein ingredient. As the moisture and pH of the samples are almost identical (and the protein and fat content by inference) then the difference in firmness is due to the WPC ingredients.

Stress and Strain Results as Measured by the Vane Test

[0200] The Vane stress results are tabulated in Table 21. The pattern of the stress data matches the firmness data with the stress of the processed cheese made from WPC392 being lower than the inventive ingredient.

[0201] The Vane strain results are tabulated in Table 21. The strain data from the IWS made from standard WPC392 is lower than that made from the inventive ingredient.

Melt

[0202] The melt results are presented in Table 21. The IWS made from standard WPC392 melts significantly less than that made from the inventive ingredient.

Summary

[0203] IWS made with the inventive ingredient melted more than cheese made with WPC392 [0204] IWS made with the inventive ingredient was firmer than cheese made with WPC392 [0205] IWS made with the inventive ingredient had lower in-process viscosity than cheese made with WPC392 [0206] The composition of the slices was relatively uniform (moisture and pH) as was the microstructure. This suggests that any textural differences are not due to compositional variation.

Example 0.8

[0207] Characterisation of the Liquid Stream Emerging from the High Pressure Tubular Reactor Prior to Drying

[0208] FIG. 10 shows that very fine particle dispersions can be prepared ex the tubular reactor of this invention.

[0209] FIG. 11 shows that the extent of denaturation can be finely controlled in the liquid stream emerging from the tubular reactor by adjusting the combinations of the temperature and holding times.