WO2012060723A1

WO2012060723A1 - Dairy product and process

Info

Publication number: WO2012060723A1
Application number: PCT/NZ2011/000235
Authority: WO
Inventors: Ganugapati Vijaya Bhaskar; Kuldeep Yadav; Stephen Thomas Dybing; Michael Jiu Hii; Anthony Michael Fayerman
Original assignee: Fonterra Co-Operative Group Limited
Priority date: 2010-11-04
Filing date: 2011-11-04
Publication date: 2012-05-10

Abstract

A process for preparing a grindable cheese having 30-45% moisture, at least 0.5% whey protein and more than 10% fat in dry matter is provided. It involves (a) filtering milk through a membrane to remove 30% to 90% of the water and preferably also of the lactose while retaining at least 95% of the casein; (b) adding sufficient sodium chloride to the retentate to get 0.5 to 2% salt in the cheese product; (c) heating the membrane filtered milk retentate to a temperature above 75°C; (d) subjecting the membrane filtered milk retentate to a process selected from fermentation and chemical acidification or a mixture thereof to produce a fermented/acid milk with a pH of 5.4 or less; (e) (optionally) treating the prepared retentate with rennet or a suitable coagulating enzyme, either prior to or following fermentation, (f) thermally concentrating the membrane filtered milk to increase the total solids content to 55-70%, the protein content to at least 25% (g) allowing the heated milk to cool to produce a cheese. Also provided is a grindable ultrafiltration cheese prepared from milk retentate heated above 75°C and having 30-45% moisture, at least 25% protein, at least 0.5% whey protein, and more than 10% fat in dry matter.

Description

DAIRY PRODUCT AND PROCESS

Field of the invention

The present invention relates to a method of a grindable or gratable cheese and a method for preparing it.

Background of the invention The manufacture of processed cheese and spreads requires a minimum level of natural cheese. These requirements are set out in U.S. Code of Federal Regulations (CFR) - Title 21 - Food and Drugs that include sections 133.169, Pasteurized process cheese, 133.170 Pasteurized process cheese with fruits, vegetables, or meats, 133.171 Pasteurized process pimento cheese, 133.173 Pasteurized process cheese food, 133.174 Pasteurized process cheese food with fruits, vegetables, or meats, 133.175 Pasteurized cheese spread, 133.176 Pasteurized cheese spread with fruits, vegetables, or meats, 133.179 Pasteurized process cheese spread, 133.180 Pasteurized process cheese spread with fruits, vegetables, or meats. These requirements are incorporated herein by reference. The production of natural cheese is a time consuming expensive product to produce. Over recent decades, many alternative make procedures have been proposed to produce cheese more cheaply or more quickly, or both. Often these newer processes do away with

conventional cheese vats, whey draining processes and the forming of curds into cheese blocks or barrels. For instance for Cheddar cheese, these alternative make processes have official recognition. See for instance the definition of Cheddar cheese given in CFR Sec. 133.1 13

Cheddar cheese, a) Description. (1) Cheddar cheese is the food prepared by the procedure set forth in paragraph (a)(3) of this section, or by any other procedure which produces a finished cheese having the same physical and chemicai properties (emphasis added). The minimum milkfat content is 50 percent by weight of the solids, and the maximum moisture content is 39 percent by weight, as determined by the methods described in Sec. 133.5.

One of the time consuming, messy and potentially wasteful steps in the production of processed cheese is the comminution of blocks or barrels of cheese down to a sufficiently small particle size that the other ingredients can be incorporated to form a sufficiently uniform mass prior to cooking and conversion to processed cheese. Cheese types that readily grate well include Parmesan and Romano as defined in CFR 133.165 and 133.183, respectively. Parmesan has a maximum moisture content of 32% w/w, while Romano has a maximum moisture content of 34% w/w.

In contrast, Cheddar cheese has a maximum moisture content of 39%. This higher moisture content has in the past caused difficulty in grinding at ambient temperature. This especially applies to Cheddar cheese produced by means other than the traditional vat setting and dewheying processes.

Much art discloses various means to produce cheese by alternative procedures. For types of cheese similar in composition to Cheddar cheese, the processes often use ultrafiltration, or some membrane filtration system to concentrate whole milk, cheese milk or skim milk. The concentrated milk (retentate) may be fermented and/or treated with rennet of some suitable enzyme to convert kappa casein to para-kappa casein. Salt is added at some suitable stage in the process. This pre-cheese material is then concentrated usually in one or more stages involving the removal of water by thermal means. The resulting product is cooled and packed into blocks or barrels or some suitable shape for storage or shipment.

Dybing et al. (US Pat. No. 7,192,619) disclose a process for making cheese, especially

Cheddar cheese using ultrafiltration and ion exchange to reduce the calcium concentration in the dairy stream.

Mehnert et al. (US Pat. No. 6,242,016) disclose a rapid process for the manufacture of grated parmesan cheese. Coulter et al., (U.S. Pat. No. 3,988,481 ), teach the preparation of cheese from milk which has been de-lactosed and de-watered by a process involving molecular sieving a standardized milk to substantially separate and remove lactose and water-soluble minerals from the milk to render the milk substantially sugar-free, and adding a curd-forming agent to produce curd. Maubois et al., (U.S. Pat. No. 3,914,435), teach a manufacturing process whereby cheese is prepared from heat-treated milk without a conventional drainage step. This process involves ultrafiltering of the milk to produce a concentrate having essentially the composition of cheese produced by conventional whey draining processes. The process allows the milk, after ultrafiltration, to be heat-treated without making the milk more difficult to coagulate with rennet, . which difficulty normally occurs when milk is heated to high temperatures.

Wargel et al., (U.S. Pat. No. 4,244,971 ), teach the manufacture of cheeses and process cheese from ultrafiltered milk. Rubin et al., U.S. Pat. No. 4,401 ,679, disclose a process for preparing cheese base by concentrating milk through ultrafiltration, combined with diafiltration and evaporation, wherein the retentate from the ultrafiltration is inoculated with a lactic acid culture before evaporation. After evaporation, acidification proceeds to completion during and after packaging.

Further, cheese base material has been taught by evaporating moisture from retentate under turbulent conditions to provide a lower moisture condition. Such a process is described in an article by Ernstrom et al., entitled "Cheese Base for Processing: A High-yield Product from Whole Milk by Ultrafiltration," Journal of Dairy Science, Volume 63, pp. 228-234 (1980). The article teaches a process wherein whole milk of normal pH, or acidified to a pH of 5.7, is concentrated by ultrafiltration to about 40 percent of the original milk weight and diafiltered at constant volume until a desired ratio of lactose to buffer capacity is established. The retentate is further concentrated by ultrafiltration to 20 percent of the original milk weight. The retentate is then inoculated with cheese starter and incubated to completely ferment the residual lactose. The pH is controlled by adjusting the level of lactose from the diafiltration step of the process. The product is further concentrated in a swept-surface vacuum-pan evaporator or a Luwa evaporator. It is pointed out that the use of a batch evaporator is necessitated when the retentate, upon fermentation, curdles or coagulates, since such a product cannot be readily processed in any continuous-flow evaporator. See also Ernstrom in US 4,689,234.

It is also known to add salt during fermentation to prevent coagulation - see US 5,356,639 (Jameson and Sutherland). Aird et al. (US. Pat. No. 7,582,323) disclose a process using ultrafiltration and thermal concentration to produce a cheese without the use of emulsifying salts.

Hitherto these processes have not been especially successful because of the high viscosities involved and the propensity for highly concentrated solutions and emulsions to gel inadvertently. More importantly, the texture of the finished cheese has meant that efficient comminution for processed cheese manufacture has been a major unresolved problem.

It is an object of the present invention to provide a grindable cheese, and/or a process for preparing a grindable cheese using a membrane filtration process, or it is an object to at least provide the public with a useful choice. Disclosure of the invention

In one aspect the invention provides a process for preparing a grindable cheese having 30-45% preferably 30-39% moisture, at least 0.5% whey protein and more than 10% fat in dry matter, the process comprising:

(a) filtering milk through a membrane to remove 30% to 90% of the water and preferably also of the lactose while retaining at least 95% of the casein;

(b) adding sufficient sodium chloride to the retentate to get 0.5 to 2% salt in the cheese product;

(c) heating the membrane filtered milk retentate to a temperature above 75°C

(d) subjecting the membrane filtered milk retentate to a process selected from fermentation and chemical acidification or a mixture thereof to produce a fermented/acid milk with a pH of 5.4 or less;

(e) (optionally) treating the prepared retentate with rennet or a suitable coagulating enzyme, either prior to or following fermentation,

(f) thermally concentrating the membrane filtered milk to increase the total solids content to 55-70%, and the protein content to at least 25%

(g) allowing the heated milk to cool to produce a cheese. The heat treatment step may be carried out at any time up to the thermal concentration step including before membrane filtration; preferably it is carried out after fermentation and any renetting.

The process does not involve syneresis and whey separation.

In another aspect the invention provides a ground cheese comprising carrying out the above process followed by grinding the cheese to produce a ground cheese. The invention also provides processes for preparing a cheese of the invention and grinding, grating, shredding, or otherwise comminuting cheese to prepare a grated cheese.

Preferably 65% - 95% of the lactose is removed, most preferably 80% - 90%.

The milk is preferably standardised to the required fat content before membrane filtration

The membrane concentration facility is preferably an ultrafiltration process. The milk or membrane concentrated milk preferably undergoes decalcification. This is preferably performed using ion exchange methods for example as taught by Bhaskar et al. in U.S. Patents. Nos. 7,157,108 & 7,192,619. The fermentation involves using typical cheese making lactic food approved cultures.

The thermal concentration is conducted preferably using an evaporator and more preferably a scraped surface evaporator and most preferably a wiped-surface falling-film (thin-film) evaporator.

Definitions

A grindable or gratable cheese is defined in 21 CFR Sec. 133.146 Grated cheeses. Grated cheeses is the class of foods prepared by grinding, grating, shredding, or otherwise

comminuting cheese of one variety or a mixture of two or more varieties. Such cheeses include cheeses that when ground do not in any way interfere with cheese grinder throughput or conveyance of the cheese particles to the cooker.

The term "comprising" as used in this specification means "consisting at least in part of". When interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

The term "calcium ions" is used broadly and includes ionic calcium and colloidal calcium unless the context requires otherwise. The term "magnesium ions" is used broadly and includes ionic magnesium and colloidal magnesium unless the context requires otherwise.

Where a reduction in calcium is indicated, a corresponding reduction in magnesium is implied.

The term "renneting" refers to treating with milk coagulation enzymes including calf rennet and also other enzymes, for example, microbial cheese coagulation enzymes.

An "emulsifying salt" or "melting salt" is a salt, or combination of salts, used in conventional processed cheese manufacture to sequester calcium and impart desired properties to the product such as, but not limited to, texture, mouth feel and melt. These salts include phosphate salts and salts of organic acids. Examples are sodium and potassium salts that are

phosphates, tartrate or citrates. Emulsifying salts are typically selected from the group consisting of one or any mixture of two or more of the following: monosodium phosphate, disodium phosphate, dipotassium phosphate, trisodium phosphate, sodium metaphosphate (sodium hexametaphosphate), sodium acid pyrophosphate, tetrasodium pyrophosphate, sodium aluminum phosphate, sodium citrate, potassium citrate, calcium citrate, sodium tartrate, and 5 sodium potassium tartrate. Sodium chloride and potassium chloride are not emulsifying salts in the art. Processed cheese typically contains about 1 - 4% wt/wt emulsifying salts.

A preferred "low melting salts" processed cheese refers to processed cheese prepared with less than 75% of the amount of melting salts, defined above, normally required by a skilled worker 10 to make processed cheese. A more preferred "low melting salts" processed cheese refers to processed cheese prepared with less than 50% of the amount of melting salts normally required by a skilled worker to make processed cheese. Melting salt-free processed cheese refers to processed cheese made without the typically required addition of any of the emulsifying salts defined above.

[ 5

The term "reduced sodium" cheese or processed cheese refers to cheese or process cheese made with at least 25% less sodium than normally present in the typical product.

An "ultrafiltration cheese" is a cheese that is prepared using ultrafiltration of the cheese milk, 10 with subsequent fermentation/acidification, to produce a cheese. Ultrafiltration cheese usually is made by procedures that eliminate syneresis, or the whey separation step. However, ultrafiltration cheese can be made from concentrated ultrafiltration milk retentates that subsequently are coagulated with rennet, and then cut to induce significantly less syneresis or whey drainage.

5

Preferred embodiments

The milk may be pasteurised according to local food safety regulations.

Preferably the cheese product contains 30-39% moisture. Moisture of 30-35% is particularly 50 preferred. The protein content is preferably 27-45%, more preferably 27%-35%. The casein content is preferably 23%-33% more preferably 25%-30%. Preferably the whey protein to casein weight ratio is in the range 0.02-0.25, preferably 0.10-0.25, most preferably 0.15-0.25. Particularly preferred is cheese having the same casein to whey protein ration as the milk starting material.

The fat content of the milk may be adjusted by known separation and blending methods to give a milk stream with a selected fat content that is determined by the required FDM (fat ii dry matter content, also fat on a dry basis (FDB)) of the final cheese. For instance Cheddar cheese has a minimum FDM of 50% as specified in CFR Sec. 133.113 Cheddar cheese. In the invention the FDM is preferably 10-40%. The milk may be concentrated using membrane filtration such as ultrafiltration or microfiltration. Such systems are known in the art of dairy processing. When ultrafiltration is used, a membrane with a molecular weight cut-off of at least 1 ,000 Daltons is preferred. Preferred membranes are supplied by Synder Filtration [4941 Allison Parkway, Vacaville, CA], model VT or MT (poly-ether-sulphone [PES] type) with molecular weight cut-offs of 3,000 and 5,000, respectively. Generally the molecular weight cut off is in the range 1 ,000-10,000 D.

The filtration may be conducted hot or cold, but hot is preferred to reduce the viscosity of the retentate. A processing temperature greater than 50°C is preferred and greater than 55°C is more preferred and a temperature about 60°C - 65°C is most preferred. Diafiltration may be used as part of the filtration process and is known in the art.

The final retentate of a fat-standard cheesemilk for producing a Cheddar cheese should have a solids content of preferably at least 40% and more preferably at least 42% and a protein to lactose ratio of greater than 5 and preferably greater than 10.

In some embodiments, before or after membrane filtration, the milk stream may have a portion of its calcium replaced, preferably at least 20% more preferably 20-95% and even more preferably 25%-90% and most preferably at least 30%-85% replaced with mono valent cations such as sodium or potassium ions. The calcium replacement may also include magnesium replacement. The calcium removal may be effected by methods taught in U.S. Pats. No.

7,157,108 & 7,192,619. The calcium concentration in the milk may also be manipulated using a calcium sequestering or chelating agent such as salts of EDTA, phosphate, citrate etc.

In a further aspect the reduced calcium cheese had the surprising property of grindability and - the ability to be used for the preparation of a low sodium or melting salts-free processed cheese. Such processed cheeses are prepared melting cheese and cooking it with water and optionally other ingredients, then cooling to obtain processed cheese. Use the reduced calcium cheeses of the invention in preparing processed cheese generally lowers the requirement for melting salts in the processed cheese mixture.

The acidity or pH of the treated streams may be adjusted using food approved acids, for example hydrochloric or lactic acid, or acidulants, for example glucono-delta-lactone Salt (sodium chloride) may be added to the dairy stream. Preferably salt is added prior to fermentation to 0.5% to 2%, preferably 1 -2%. Preferably the amount of salt added will bring the final salt concentration to 1 .5%-2.5% in the cheese.

The de-lactosed and decalcified milk may be fermented using any approved cheesemaking organism - usually a lactic acid producing strain. During the fermentation the lactose is further reduced and the pH falls 5.4 or below, preferably 4.9 to 5.4, more preferably 5.0 to 5.3, most preferably 5.1 to 5.2.

In some embodiments, the fermented mixture is proteolysed (renneted) with a food approved enzyme to convert at least 65% of the kappa casein to para-kappa casein. Renneting may be used at any stage of the process before the thermal concentration step. Preferably renneting occurs after fermentation.

The dairy stream is heat treated to stabilize the protein-fat emulsion. Various time and temperature combinations may be used and temperatures above 75°C are surprisingly beneficial. Temperatures of 80°C to 100°C are convenient and 90°C to 100°C are preferred and the holding time may be from 8 s to 30 minutes, or from 10s to 30 minutes, but 20s to 360s is preferred.

The dairy stream may be concentrated using an evaporator or other convenient water removal device. Preferably the evaporator is a falling film evaporator or a scraped surface evaporator, more preferably the device is a swept-surface vacuum-pan evaporator, or a thin-film evaporator. The evaporation is conducted with a boiling temperature below 60°C and preferably less than 50°C and more preferably less than 40°C.

The evaporated product may be removed using a twin screw/multi screw extraction system. The concentrated cheese product may be formed and packaged into blocks or barrels using known art packaging systems.

Packaged product may be stored or shipped prior to final use. Generally storage or shipment would use chilled conditions of less than 10°C and preferably less than 5°C.

Once required for use and upon the removal of the packaging, the cheese may be ground. Commercially available grinding equipment may be used, for example suitable equipment is marketed by Wofking Danmark A/S (Denmark), Blentech Process Systems, Santa Rosa, CA, Urschel Machinery, Urschel Laboratories Inc., Valparaiso, IN., Bepex/Reitz, Santa Rosa, CA., Damrow, Carlisle Co., Inc. Charlotte, NC. etc. The ground cheese may be used to prepare processed cheese using known art methods. For example, the ground cheese may be melted with ingredients selected from emulsifying salts, butter, cream, mature cheese, water, extra salt, acid, food colouring and whey solids, whey proteins and any other ingredients allowed by local regulations. In embodiments where the cheese ingredient has been treated to reduce the calcium

concentration, processed cheese may be prepared without the need to use calcium

sequestering salts, known in the art as melting salts.

In a preferred embodiment the invention provides a process for preparing a grindable cheese having 30-45%, preferably 30-39% moisture, at least 0.5% whey protein and more than 10% fat in dry matter, the process comprising:

(a) filtering milk through a membrane to produce a retentate that contains above 20% solids, preferably 30-60%, most preferably 35-45%;

(b) adding sufficient sodium chloride to the retentate to get 0.5 to 2.0% salt in the cheese product;

(c) heating the membrane filtered milk retentate to a temperature above 75°C

(e) thermally concentrating the membrane filtered milk to increase the total solids content to 55-70%, preferably 61 -70%, and the protein content to at least 25%

(f) allowing the heated milk to cool to produce a cheese

wherein the molecular weight cut off of the membrane is in the range 1000-10000D. In this embodiment it is preferred when the preferred features described above are present.

In another aspect the invention provides a grindable cheese prepared by a process of the invention. Preferably the process used is a preferred process described above. In a further embodiment the invention provides a grindable ultrafiltration cheese prepared from milk retentate heated above 75°C and having 30-45% moisture, at least 25% protein, at least 0.5% whey protein, and more than 10% fat in dry matter. Preferably the retentate has been treated to above 80°C and the moisture content is 30-39%.

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.

Brief Description of Figures

Figure 1 shows a diagrammatic scheme of preferred embodiments of the invention.

Figure 2 shows a graph of high fracture stress versus grindability for

• NZMP™ Cheddar Cheese, High Solids

■ NZMP™ Cheddar Cheese, General

A Cheddar Cheese for Manufacture

J Alternate Make Cheddar cheese, 42.9% FDB

Alternate Make Cheddar cheese, 50.5% FDB

Figure 3 shows the Parameterisation of the grinding smearing test. The figure shows the assessment scale for face plate smearing evaluation and demonstration of ranking by grinder scores 1 , 2, 3 - (A) Face plate clear, no smearing (Acceptable) score of 3; (B) Some smearing on face plate (Marginal) score of 2; (C) A high amount of smearing. Face plate completely covered with product (Unacceptable) score of 1.

Figure -4 shows the Parameterisation of the particle clumping test. The figure shows the assessment scale for particle size ranking evaluation as grinder scores 1 , 2 and 3 - (A) Small particles (1-5 particles sticking together, also will easily de-clump under small force)

(Acceptable) score of 3; (B) Clumps - many particles stuck together. (5-10 particles, smearing on one end to form a bundle) (Marginal) score of 2; (C) Ribbons (>~10 particles, forming continuous coils/ribbon and very hard to de-clump) (Unacceptable) score of 1.

Figure 5 provides Illustrations of different particle sizes coming out of grinder The figure shows and demonstration of grinder scores 1 , 2, and 3 - (A) Crumbs coming out of grinder (Score 3, Acceptable); (B) Clumps coming out of grinder (Score 2, Marginal); (C) Ribbon /coil coming out of grinder (Score 1 , Unacceptable).

Figure 6 shows Assessment scale for Augur Cleanliness ranking evaluation and demonstration of grinding scores 1 , 2, and 3 - (A) Augur Clean (Score 3, Acceptable); (B) Augur not clean, material sticking just in front, easy to remove by fingers (Score 2, Marginal); (C) Material sticking to most of the augur length and very hard to remove by fingers (Score 1 , Unacceptable).

Examples

The invention consists in the foregoing. The following examples are intended to further illustrate the invention

Example 1.

The following example illustrates the elements required to produce an "alternative-make" Cheddar cheese with compositions that enhance grindability. The example describes the production of both a full fat and a reduced fat Cheddar cheese by the novel process, as well as the selection of commercially prepared cheeses for comparison.

Cheese preparation or selection:

Manufacture of an alternative make Cheddar cheese with a high protein, standard fat content to improve grindability began with receiving and pasteurizing milk. The milk was pasteurized at 74°C (165.2°F) for 16 s using a plate heat exchanger by the standard high-temperature-short time method. The milk was then cooled to 5°C (41 °F) and combined with sufficient cream to produce a standardized blend with a protein-to-fat ratio of 0.84. The standardized milk was heated to at least 60°C (140°F) and fractionated with ultrafiltration as supplemented with the addition of water to achieve diafiltration by standard procedures using membranes with a 5 kD cut-off (Synder Filtration, Vacaville, CA). The ultrafiltration/diafiltration processing created a retentate with 39.8% total solids, 20.4% fat, and 16.2% protein. The retentate was cooled to 30° C (86°F), combined with enough salt to produce 1.8% salt in the finished cheese, and inoculated with a standard lactococcus lactis subsp. lactis cheese starter culture. Fermentation produced enough lactic acid in 12 hours to reduce the pH of the retentate to 5.2. The fermented retentate was then combined with Fromase XL 750 cheese coagulant (DSM Food Specialties, Delft, Holland) using an in-line static mixer attached to a pump. Coagulant was added at the rate of 0.03 ml Fromase/ kg retentate. The treated retentate was allowed to react for 2 min., heated to 85°C (185°F) for about 3 min., passed through a flash vessel operated at a vacuum sufficient to reduce the retentate temperature to approximately 34°C (93.2°F) Final moisture adjustment by evaporation proceeded in a 0.5 sq meter thin-film evaporator (TFE) (LCI Corporation, Charlotte, NC) operated at a pressure of 27 mBar (abs) and a rotor speed of 1 100 5 rpm to produce a finished product with 68.5% total solids, 34.6 % fat, 27.1 % total protein, and a fat-on-a-dry basis (FDB) of 50.5%. The finished cheese was vacuum packaged, refrigerated, and stored until further analysis and use.

Manufacture of an alternative make reduced fat Cheddar cheese with a high protein content [0 providing excellent grindability began with the receipt of raw milk. The milk was immediately pasteurized at 74°C for 16 s, cooled to 5°C and combined with pasteurized skim milk to produce a standardized blend with a protein-to-fat ratio of 1.2. The standardized milk was then heated to at least 60°C and fractionated with ultrafiltration and diafiltration by the previously described equipment and procedures to create a retentate with 40.6% total solids, 16.3% fat, and 19.7% 15 protein. The retentate was cooled to 30° C, combined with sufficient salt to produce 1.8% salt in the finished cheese, inoculated with the same starter culture strain, and fermented to pH 5.2 in 12 h. The fermented retentate was then combined with 0.014 ml Fromase XL 750 per kg retentate using the same in-line static mixer, allowed to react for 2 min., heated to 85°C for about 3 min., passed through a flash vessel, and evaporated in the same thin-film evaporator >0 operated as previously described above to create a finished product with 63.4% total solids, 27.2% fat, 30.8% total protein, and 42.9% FDB. The finished cheese was vacuum packaged, refrigerated, and stored until further analysis and use.

Table 1 shows the composition of the standardized milk, completed ultrafiltration retentate, and 15 finished Cheddar cheese produced by the described process.

Table 1. Composition of standardized milk, finished retentate, and finished cheese.

Lactose¹ 4.7 1 .6 2.3 4.5 2.8 0.9

Ash 0.7 1 .6 2.6 0.8 1 .8 2.8

Salt 1 .9 1 .7

FDB² 31 .1 51 .25 50.5 25.0 40.15 42.9

²FDB = fat-on-a-dry-basis or the percentage fat divided by the total solids, quantity multiplied by 100. The term is equivalent to fat-in-dry-matter, or FDM.

In a further series of production runs, samples were prepared using the process described above with selected variations to demonstrate the invention. In one sample, the renneting step was omitted; in another run, the same process as detailed was repeated to demonstrate replication, and in a third (non-inventive [control]) run a reduced heat treatment was applied. The product details and composition data for the three products are shown in Table 2.

Table 2. Composition details of alternative make cheese samples

Viscosity of heat treated stream prior to evaporative concentration

In another aspect, the viscosity of the acidified (with or without rennet) retentate was examined to assess processability through the evaporator.

Table 3 shows a summary of the processing conditions that illustrate the scope of the invention. Surprisingly, it was revealed that only after heat treatments above about 80°C were high protein samples able to achieve a satisfactory combination of processability i.e. evaporative

concentration without blockage of the TFE evaporator, and grindability. That is, heating the . high protein retentate stream to temperatures >85°C (185°F) greatly enhanced the ability of the retentate stream to pass through the TFE in a manner to achieve effective removal of the water to produce the desired total solids (dry matter [DM]) in the finished product e.g. about 65% kg DM/kg and simultaneously, the heat treatment surprisingly achieved the desired outcome of a final product with greatly improved grindability.

N.A. for grindability means that no sample was able to be produced to assess grindability.

Table 3. Summary of performance of inventive and non-inventive samples and processing treatments

Fromase Solution: 5ml in 3 L (stock solution), dilution: 0.001667 dosing rate: 900 mL/h, feed rate: 50 kg/h dosing: 18mL/kg of stock solution = 0.03 mL Fromase/kg of feed

Retentate pH: 5.2

Viscosity before heat treatment: P/F: 0.8: 0.130 Pa.s, and P/F: 1.22: 0.265 Pa.s

Reference Cheeses

Commercially prepared Cheddar cheese, High Solids and Cheddar Cheese, General (Fonterra Co-operative Group, Ltd., Auckland, New Zealand) were selected for comparison to the prepared alternate make Cheddars described above. Both products are commonly used in the manufacture of process cheese and related products, and are regarded to have excellent grindability. Commercially prepared Cheddar Cheese for Manufacture (California Dairies, Inc., Visalia, CA) was also selected for comparison to the prepared alternate make Cheddars described above. The Product Technical Reference Sheet claims that Cheddar cheese for manufacture is the cheese made from pasteurized, standardized milk, concentrated through a series of UF

(ultrafiltration) membranes which remove lactose and water. The mix is pumped into a fermentation silo and inoculated with culture, which facilitates lactic acid development. After final pH development has occurred (to between pH 4.95 to 5.30) rennet is added as the mix is heated and further concentrated through an evaporator and processor. This sample allows comparison with a typical cheese made by current procedures. Table 4 shows the composition of the comparison cheese samples.

Table 4. Composition of commercially prepared Cheddar cheese samples used for comparison.

¹NZMP™ Cheddar Cheese High Solids (Fonterra Co-operative Group, Ltd., (Auckland, New Zealand), PB 123, Version 3. 0309. ²NZMP™ Cheddar Cheese General (Fonterra Co-operative Group, Ltd., (Auckland, New Zealand), PB 119, Version 8. 0309.

³Cheddar Cheese for Manufacture. California Dairies, Inc. (Visalia, CA), Product technical reference sheet. TS-LBCCFM 2/17/06.

4FDB = fat-on-a-dry-basis or the percentage fat divided by the total solids, quantity multiplied by 100. The term is equivalent to fat-in-dry-matter, or FDM.

Analysis for Grindability

The prepared alternate make Cheddars and selected commercially prepared samples were separately ground in a Reitz grinder (Bepex/Reitz, Santa Rosa, CA) equipped with a 300 mm barrel and a 60 mm orifice plate. The grindability of each sample was subjectively assessed as follows:

NZMP™ Cheddar Cheese High Solids (of Table 4) ground very well, and was assigned an arbitrary score of 4 for good grindability;

NZMP™ Cheddar Cheese General (of Table 4) and the alternate make, reduced fat (42.9%

FDB) Cheddar (of Table 3) ground well, and were assigned a score of 3 for good/acceptable;

The alternate make, standard Cheddar (50.5% FDB) (of Table 3) showed acceptable

grindability, and was assigned a score of 2 for acceptable; and

The Cheddar cheese for manufacture (of Table 4) showed poor grindability, and was assigned a score of 1 for Not Acceptable.

The prepared and selected Cheddar cheeses were analyzed by the ISO/IDF lubricated uniaxial compression test (ISO/IDF, 2006), which includes a fracture stress measurement. Fracture stress measurements correlate directly with cheese firmness (Watkinson, et al., 2001 ), and as such correlate to grindability based on the well established principles of brittle - ductile fracture behaviour in materials engineering.

Samples from each cheese were cut into cylinders 20 mm in diameter by 25 mm in length. The samples were tempered to 13°C (55.4°F) and then evaluated with a TAHD compression tension test instrument (Stable Micro Systems, Godalming, UK) using a 50 kg load cell as described by Watkinson et al. (1997). The fracture stress was determined for each sample upon

compression to 80% between two parallel Teflon plates. Six duplicate pairs of each sample were evaluated, with the results shown in Figure 2.

Figure 2 correlates greater fracture stress to improved grindability for the Cheddar cheese samples evaluated. The highest fracture stress occurred with the NZMP™ Cheddar Cheese General, NZMP™ Cheddar Cheese High Solids, and alternate make Cheddar with 42.8% FDB. The NZMP™ Cheddar High Solids subjectively demonstrated the best grindability, being assigned a score of 4 and a rating of good. The NZMP™ Cheddar Cheese General and the alternate make Cheddar with 42.8% FDB both also showed a high fracture stress, while having an equivalent grindability score of 3. The lower fracture stress result for the alternate make Cheddar cheese with 50.5% FDB correlates with a lower grindability score of 2 for this sample. However, the grindability of the alternate make Cheddar with 50.5% FDB is a major

improvement over the unacceptable grindability of the Cheddar cheese for manufacture produced by the standard procedures.

LAB SCALE GRINDER TEST RESULTS

The ability of the alternative make cheese samples to undergo grinding successfully was examined using a laboratory-scale grinder prepared from a modified meat mincer. Cheese samples were supplied to the feed throat of the grinder in the form of a solid rod of cheese approximately 500 mm long and 25 mm in diameter. A constant load of 3 kg was applied to the top of the rod of cheese to apply uniform pressure to auger feed.

Evaluation scores for grinder faceplate smearing, auger smearing and particle size category were based on the scales defined by the test images given below in Table 5.

Refer to Figures 3 - 6 for parameterisation of the grinding tests. Table 5. Table of Results for Lab Scale Grinder (average of 3 Repeat)

Size (g)

Particle cluster 2 1.5 1

size rank

Summary of results The properties of the inventive samples could be readily distinguished from the non-inventive controls. It was surprisingly found that the high heat treatment step was crucial for both effective plant performance and grindability. Without being bound to any specific theory, it is believed that the resulting reduction in viscosity that arose from heat treatments above about 80°C enabled the plant to operate at high capacity and deliver a product (either renneted or non-renneted) that was commercially grindable and able to produce an acceptable processed cheese.

Functionality in Process Cheese Manufacture

The alternate make Cheddar cheeses were used to produce Pasteurized Process American Cheese Food to demonstrate the functionality of these cheeses as an ingredient for the manufacture of process cheese and related products. Table 6 shows the formulations used to produce the pasteurized process American cheese food, with the calculated composition of the finished products provided in Table 7.

Table 6. Pasteurized Process American Cheese formulations.

Zealand), PB 123, Version 3.0309.

²NZMP™ Cheddar Cheese: General (Fonterra Co-operative Group, Ltd., Auckland, New Zealand), PB 119, Version 8.0309.

³Cheddar Cheese made by alternate make procedure to a FDB of 42.8%, as described above. ⁴Cheddar Cheese made by alternate make procedure to a FDB of 50.5%, as described above. . ⁵NZMP™ Unsalted Creamery Butter, (Fonterra Co-operative Group, Ltd., Auckland, New Zealand), PB 097, Version 7.1009

⁶NZMP™ Whey Powder 621 (Fonterra Co-operative Group, Ltd., Auckland, New Zealand), PB 175, Version 6.0509. ⁷NZMP™ Edible Lactose (Fonterra Co-operative Group, Ltd., Auckland, New Zealand), PB 199, Version 6.0109.

⁸TSC = Trisodium citrate, dihydrate, Jungbunzlauer, Austria.

9DSP =Disodium Phosphate dihydrate, Innophos, New Jersey, USA

1⁰Salt (sodium chloride), Pacific Salt, New Zealand. -

¹¹Sorbic Acid, Diacel Chemical LTD Tokyo, Japan.

Table 7. Calculated compositions of finished Pasteurized Processed American Cheese Food samples.

The same cooking process was used to prepare all formulations. Manufacture of the

pasteurized process cheese food began with the grinding of the cheese and butter in the previously described Reitz grinder. Approximately one half of the ground cheese and butter were then added to a twin screw, process cheese cooker (Blentech CC45, Petaluma, CA) having a 20 kg capacity. The cheese and butter mixture was blended together at low speed, approximately 40 rpm, for 2 to 2.5 minutes, and then the emulsifying salts, lactose, dry sweet whey, salt, and sorbic acid added to the cooker over an additional minute. Blending continued at 40 rpm for another minute, then the remaining cheese and the water added to the blend in the cooker. The completed mixture was blended at 40 rpm for 5 minutes, then the agitators turned off, and the blend allowed to sit quiescently for 5 minutes.

The prepared, blended ingredients were cooked to a temperature of 85°C by direct steam injection, the formulation allowing for the added water as steam condensate. The controlled temperature increase achieved the desired cooking temperature in about 5 minutes with the auger speed adjusted to 120 rpm. The cooked mixture was held at 85°C for 2 minutes, then produced into 76 x 76 mm slices with a thickness of 1.75 mm. The slices were wrapped and held at refrigeration temperatures of <5°C (41 °F) until analysis. Table 8 shows the finished product moisture, total solids, and pH as well as the analytical results for melt and body and texture as shown by the cylinder and vane tests.

Table 8. Moisture, total solids, and pH with melt test, cylinder test, and vane test results for pasteurized process American cheese.

Moisture determined via forced air oven method, at 105°C for 16 hours.

²Melt determined by the Schreiber melt test (Zehren, V. L, and D. D. Nusbaum. 1992.).

3Cylinder = Texture Analyzer Cylinder method.

4Brookfield Vane = Brookfield Vane test method.

⁵Both Texture Analyzer Cylinder and Brookfield Vane test methods described in (Drake, M. A., V. D. Truong, and C. R. Daubert. 1999.).

Each product resembled similarly cooked, high quality pasteurized process American cheese food at the completion of cooking. No free fat was observed for any product indicating the production of the desired emulsion. Cooked product from each formulation readily gelled within 30 seconds to 1 minute after being spread upon the casting table. The gelled products made from each formulation all cut cleanly to form highly acceptable slices. These slices were readily detached from the table and were packaged in film without losing the desired shape or sticking to either the table or film surfaces. Finished slices produced from each formulation required 6 or more rubs between the thumb and fingers to break, subjectively indicating the production of a commercially acceptable emulsion with the desired stability. Therefore, the alternate make Cheddar maintained excellent functionality when used as ingredient in the manufacture of pasteurized process American cheese food.

Table 8 shows the melting ability and firmness of the pasteurized process American cheese foods produced. The ability of the samples to melt was measured by the Schreiber test

(Zehren, V. L, and D. D. Nusbaum. 1992.). Cheese firmness was determined by instrumental texture profile analysis (Drake, M. A., V. D. Truong, and C. R. Daubert. 1999.) Most commercial applications require pasteurized process American cheese food to have a Schreiber melt score of > 3 to 4. The melting ability of the slices made by all the treatments exceeds the typical minimal melting requirements. Surprisingly, the functionality of the alternate make grindable Cheddar cheeses shown in Table 8 and described herein meets all the requirements for use as an ingredient in the manufacture of pasteurized process American cheese food.

The firmness of pasteurized process American cheese food produced with alternate make Cheddar exceeded the firmness of control product made with traditional Cheddar. Although the total protein and casein content of the formulation containing the alternate make Cheddar with 42.8 FBD is lower than for the control formulation, the pasteurized process American cheese made with the alternate make Cheddar is firmer than the control. The results indicate that the available protein and casein delivered in the alternate make Cheddar is fully dispersed through the structure of the resulting pasteurized processed American cheese food slices. Therefore, the inventive alternate make Cheddar delivers full functionality. Example 2.

The following example illustrates the production of an "alternative-make" Cheddar cheese by procedures that achieve decalcification by ion exchange. Cheese manufacture:

Manufacture of alternative make Cheddar cheese was evaluated in two separate trials at either 20 or 40% decalcification. , Both trials began with the standardization of an independent shipment of raw milk with sufficient cream or skim milk to produce blended milk with a protein- to-fat ratio of approximately 0.80. Both separate lots of standardized milk were then separately pasteurized at 74°C (165.2°F) for 16 s using a plate heat exchanger by the standard high- temperature-short time method. A suitable portion of both lots of milk was separated for ion exchange treatment. The remaining portion of each standardized milk, nontreated milk was held separately at 5°C.

Suitable portions of each of the prepared, standardized milks selected for decalcification were cooled to 10°C and independently introduced into a charged, strong acid cation ion exchange column AMBERLITE™ SRILNa. Ion exchange processing replaced the available divalent cations in the milk consisting of calcium, and magnesium with sodium. The independent portions of calcium-depleted milk were then combined with a suitable amount of the respective non-treated milk to produce separate, independent lots of calcium depleted milk calculated to produce either nominally 20 or 40% calcium (and magnesium) depletion.

Each lot of prepared milk, i.e. nominally 20% calcium depleted and the respective standardized, non-calcium depleted milk, and nominally 40% calcium depleted milk and the respective standardized non-calcium depleted milk were independently heated to at least 50°C (122°F) and fractionated with ultrafiltration. The ultrafiltration treatment was supplemented with the addition of water to achieve diafiltration by standard procedures using membranes with a 5 kD cut-off (Parker Hannifin Corp., Cleveland, OH). The retentate was cooled to 30° C (86°F), combined with enough salt to produce 1.8% salt in the finished cheese, and inoculated with a standard lactococcus lactis subsp. lactis cheese starter culture. Fermentation produced enough lactic acid in 12 hours to reduce the pH of the retentate to 5.2. The fermented retentate was then combined with Fromase XL 750 cheese coagulant (DSM Food Specialties, Delft, Holland) using an in-line static mixer attached to a pump. Coagulant was added at the rate of 0.03 ml Fromase/ kg retentate. The treated retentate was allowed to react for 2 min., heated to 85°C (185°F) for about 3 min., passed through a flash vessel operated at a vacuum sufficient to reduce the retentate temperature to approximately 34°C (93.2°F) Final moisture adjustment by evaporation proceeded in a 0.5 sq meter thin-film evaporator (TFE) (LCI Corporation, Charlotte, NC) operated at a pressure of 27 mBar (abs) and a rotor speed of 1 100 rpm to produce a finished product. Tables 9 and 10 shows the composition of retentates and finished Cheddar cheese for either 20 or 40% of calcium and magnesium depletion, actually equalling about 18 and 30% calcium depletion. The finished cheese was vacuum packaged, refrigerated, and stored until being evaluated for grindability. Table 9. Composition and cation depletion of retentates and Cheddar cheese in 20% deplete trial.

Component Retentate Non- Cheddar Non- Retentate 20% Cheddar 20% calcium Deplete Calcium Deplete Calcium Deplete¹ Calcium Deplete¹

Moisture (%) 61.54 35.85 61.54 35.85

Total Solids (%) 38.46 64.15 38.46 64.15

Fat (%) 19.7 32.1 19.69 31.57

Total Protein (%) 15.76 25.07 15.53 25.49

Lactose ² (%) 1 .48 2.98 1.89 2.59

Ash ³ (%) 1.52 2.27 1 .35 2.11

Salt (%) N.A. 1.73 N.A. 1 .77

Ca ⁴ - (mg/kg) 4360 7125 3555 5888 Mg (mg/kg) 206 333.5 162.6 275

Ca Depletion (%) N.A. N.A. 18.5 17.4

¹ The 20% deplete retentate and Ched dar compositional values are normalized to the equivalent total solids of the respective non-calcium deplete retentate and Cheddar for equivalent comparison.

² Lactose determined by difference.

3 Ash does not include salt.

⁴ Calcium and magnesium concentrations were measured using standard ICP methods

(inductively coupled plasma).

Table 10. Composition and cation depletion of retentates and Cheddar cheese in 40% deplete trial.

total solids of the respective non-calcium deplete retentate and Cheddar for equivalent comparison.

2 Lactose determined by difference.

3 Ash does not include salt.

The calcium deplete cheese were assessed for grindability using the methods described herein. Generally, the Cheddar cheeses prepared with the calcium depleted retentates show

acceptable grindability, equalling the grindability of the Inventive samples prepared in Example 1. Additionally the grindability of the Cheddar cheeses prepared with the calcium depleted retentates exceeded the grindability of the Non Inventive Cheddar cheese prepared in Example 1. References

Drake, M. A., V. D. Truong, and C. R_f Daubert. 1999. Rheological and sensory properties of reduced-fat processed cheeses containing lecithin. J. Food Sci. 64: 744-747.

Ernstrom, C. A., B. J. Sutherland, and G. W. Jameson. 1980. Cheese base for processing. A high yield product from whole milk by ultrafiltration., J. Dairy Sci. 63:228-234. ISO/IDF Technical specification - ISO/TS 17996 I IDF/RM 205. 2006. Cheese - determination of rheological properties by uniaxial compression at constant displacement rate. International Dairy Federation, Brussels, ISO, Geneva. First edition 2006-09-01.

Watkinson, P., C. Coker, R. Crawford, C. Dobbs, K. Johnston, A. McKenna, and N. White. 2001. Effect of cheese pH and ripening time on model cheese textural properties and proteolysis. Int. Dairy J. 11 :455-464,

Zehren, V. L, and D. D. Nusbaum. 1992. Process Cheese. Cheese Reporter Publishing Co., Inc. Madison, Wl. pp.294-295.

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Claims

CLAIMS:

1. A process for preparing a grindable cheese having 30-45% moisture, at least 0.5% whey protein and more than 10% fat in dry matter, the process comprising:

(c) heating the membrane filtered milk retentate to a temperature above 75°C

(d^ subjecting the membrane filtered milk retentate to a process selected from fermentation and chemical acidification or a mixture thereof to produce a fermented/acid milk with a pH of 5.4 or less;

(f) thermally concentrating the membrane filtered milk to increase the total solids content to 55-70%, the protein content to at least 25%

(g) allowing the heated milk to cool to produce a cheese.

2. A process as claimed in claim 1 wherein the heat treatment step is carried out after fermentation and any rennetting.

3. A process as claimed in claim 1 or claim 2 wherein the cheese is ground to produce ground cheese.

4. A process as claimed in any one of claims 1 to 3 wherein said filtering milk is carried out by an ultrafiltration process.

5. A process as claimed in any one of claims 1 to 4 wherein the milk or membrane concentrated milk undergoes decalcification.

6. A process as claimed in claim 5 wherein the decalcification is ion exchange.

7. A process as claimed in any one of claims 1-6 wherein the fermentation comprises using cheese making lactic food approved cultures.

8. A process as claimed in any one of claims 1-7 wherein the thermal concentration is conducted using an evaporator, preferably a scraped surface evaporator and more preferably a wiped-surface falling film (thin-film) evaporator.

9. A process of any one of claims 1 , 2 and 4-8 comprising the further step of grinding, grating, shredding, or otherwise comminuting cheese.

10. A process as claimed in any one of claims 1 -9 wherein before or after membrane filtration, the milk stream has at least 20% of its calcium replaced with sodium or potassium ions.

1 1. A process of preparing a processed cheese comprising preparing cheese by a method as claimed in any one of claims 1-10, melting the cheese and cooking it with water and any other ingredients, and cooling to obtain processed cheese.

12. A process of preparing a processed cheese wherein cheese produced by the method of claim 10 is used for the preparation of reduced sodium or melting salts-free processed cheese.

13. The process as claimed in any one of claims 1-12 wherein fermentation is used and the pH falls to pH 4.9-5.4.

14. A process as claimed in any one of claims 1-13 wherein the retentate is heated to at least 80°C.

15. A process as claimed in claim 13 wherein the grindable cheese has a moisture content of 30-39% and in step (f) the concentrating increases the total solids content to 61-70%.

16. A process as claimed in any one of claims 1 -13 wherein the fermented mixture is proteolysed (rennetted) with a food approved enzyme to convert at least 65% of the kappa casein to para-kappa casein.

17. A process for preparing a a grindable cheese having 30-45% moisture, at least 0.5% whey protein and more than 10% fat in dry matter, the process comprising:

(a) filtering milk through a membrane to produce a retentate that contains above 20% solids, preferably 30-60%, most preferably 35-45%; (b) adding sufficient sodium chloride to the retentate to get 0.5 to 2.0% salt in the cheese product;

(c) heating the membrane filtered milk retentate to a temperature above 75°C

(e) thermally concentrating the membrane filtered milk to increase the total solids content to 55-70%, the protein content to at least 25%

(f) allowing the heated milk to cool to produce a cheese

wherein the molecular weight cut off of the membrane is in the range 1000-10000.

18. A process as claimed in claim 17 wherein the milk retentate is heated above 80°C and has grindable cheese 30-39% moisture.

19. A grindable cheese prepared by a process of any one of claims 1-18.

20. A grindable ultrafiltration cheese prepared from milk retentate heated above 75°C and having 30-45% moisture, at least 25% protein, at least 0.5% whey protein, and more than 10% fat in dry matter.

21. A grindable cheese as claimed in claim 20 wherein the retentate has been heated at above 80°C and the moisture content is 30-39%.