TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for the preparation of hard or semi-hard type cheese, wherein use is made of water retaining particles, which particles comprise at least seventy-five percent by weight of water. The present invention further relates to a hard or semihard cheese comprising said water retaining particles and to the use of such particles in the preparation of cheese. BACKGROUND OF THE INVENTION

Over thousands of years cheese has developed from high moisture, low acid, unsalted fresh curd with a very short shelf-life to the more stable product of today. Shelf-life stability has been improved by the addition of well-characterized bacterial cultures, purified rennet solutions or pastes, salt and a more rigorous understanding of the impact of manufacturing and storage conditions on cheese texture and flavor. As a result, for large scale commercial products, overall quality has improved.

Cheese was historically manufactured as a farmhouse product on a relatively small scale. Nowadays, it is produced on a large scale, either for consumption as a food as such or as a food ingredient. The production of cheese requires the coagulation of milk, in most cases through the action of rennet (chymosin) on the κ-casein steric stabilizing layer, which protein is predominantly located on the outside of the casein micelles.

After addition of rennet (chymosin) coagulation of the casein micelles occurs and after a gel has formed, the gel is cut and heated in order to expel moisture from the gel (syneresis) such that curd is obtained. Subsequently, the curd is drained, salted and stored such that cheese is formed. One of the most appreciated kinds of cheese are the so-called hard and semi-hard cheeses. Typical semi-hard cheeses are Gouda type cheeses and Cheddar type cheeses. A typical example of a hard cheese is Parmesan.

Traditionally Gouda type cheeses are made from cows' milk and have 40 to 50% fat in the dry matter. They are brined after being pressed and typically have a water content below

42%. In general these types of cheeses have matured for 6 weeks to about a year. Cheddar-type cheeses are on average somewhat dryer and more acidic than Gouda type cheeses. They are made in a different way, in that they are salted in the curd stage, instead of being salted after pressing as with Gouda-type cheeses. Cheddar type cheeses may be matured for 2 to 15 months.

The known hard and semi-hard cheeses comprise a considerable amount of lipids.

Typically, such cheeses comprise more than 30% by weight of the cheese lipids. However, there has been a growing interest in food products containing less fat, less cholesterol and lower calories, due to the increase of cardiovascular diseases, obesity and diabetes. In this regard it has been an aim for the dairy industry to prepare cheese with a lower fat content whilst maintaining the normal textural and functional properties of cheese.

In order to reduce the fat content of cheese, it has been suggested to replace fat present in cheese by water. However, increasing the moisture content generally decreases the firmness of cheese, i.e. a low fat cheese (i.e. cheese with a fat content of less than 30% by weight on dry matter) has different sensory properties than a full fat cheese (i.e. cheese with a fat content of more than 50% by weight on dry matter). Several fat-replacing substances have been proposed, such as cross-linked protein particles, and carbohydrates such as inulin (see for an overview Trends in Food Science & Technology 21 (2010) 85-94). However, these substances have certain drawbacks. For example, proteins are generally expensive and the addition of protein particles to cheese has been found to lead to graininess.

In this regard reference is also made to the international patent application

WO95/01729, wherein it suggested to replace at least a part of the fat content by microparticles of microcrystalline cellulose and galactomannan. Although these particles may be used as a fat substitute, they are expensive to produce and have a negative influence on cheese properties. In order to compensate this loss of properties a gelling polysaccharide needs to be used.

Reference is further made to the international patent application WO92/06598. In this application the use has been described of microgel particles which have been prepared from alginate. However, due to the method used for preparing these particles, their internal pH is relatively low, which renders them less suitable for use in cheese. Furthermore, the water retaining capacity of these particles appears to be low. Consequently, more of these particles have to be used to increase the water content of cheese, which will lead to problems with respect to texture and sensoric properties of said cheese.

Hence, a need exists for cheese having a high water content, a low fat content, but with textural and functional properties comparable to that of full-fat cheese, and which cheese does not comprise expensive additional ingredients and ingredients not commonly used in food products. A need also exists for a method for preparing such a cheese, and which method does not require a substantial modification of the cheese processing procedures.

SUMMARY OF INVENTION

A first aspect of the present invention relates to a method for preparing hard or semi-hard type cheese, comprising the steps of:

a. providing a cheese milk composition, which composition comprises:

- 40 to 90% by weight water;

- at least 2.5% by weight dairy proteins; and

at least 0.5 % by weight lipids;

b. letting the dairy proteins coagulate under the influence of a coagulant or acid, such that curd is formed;

c. forming a hard or semi-hard cheese from the curd;

wherein, in total at least 5% by weight of water retaining particles are added to the cheese milk composition and/or curd, which water retaining particles have a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μπι and wherein said water retaining particles comprise at least 75% by weight water; such that the cheese obtained comprises at least 50% by weight water.

A second aspect of the present invention relates to hard or semi-hard cheese obtainable by the above mentioned method.

A third aspect of the present invention relates to a hard or semi-hard cheese comprising:

- at least 20% by weight casein;

- less than 30% by weight lipids;

- at least 50% by weight water, wherein 15 to 50% by weight of the total amount of water is present in the cheese as water retaining particles, which particles have a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μπι and wherein said water retaining particles comprise at least 75% by weight water.

Due to the use of water retaining particles with the above mentioned water content and particle size distribution, it is possible to prepare cheese with a relatively high water content, whilst maintaining excellent textural properties.

The cheeses according to the present invention, and the cheeses prepared with the method of the present invention comprise a high amount of water, of which a considerable part is present in the water retaining particles. Due to the fact that these particles are generally smaller than 20 μπι, they will not be noticed by consumers. Furthermore, since these water retaining particles have a gel-like texture, they also contribute to the firmness of the cheese, which would not be the case if one would just increase the water content by adding additional (free) water to the cheese or the cheese milk.

The cheeses according to the present invention have the textural properties of a hard or semi-hard cheese, but have a water content which has not previously been reported for these types of cheeses. Due to the higher water content, less lipids may be used, or less protein.

DEFINITIONS

The term "hard or semi-hard type cheese" as used herein has its conventional meaning and refers to a cheese having a compression modulus "E" of 1 * 10 ⁵ Pa or higher at 20°C, as described in Fox, P.F. et al., Cheese Chemistry, Physics and Microbiology, vol.1, 2004.

The term "dairy protein" as used herein has its conventional meaning and refers to proteins, such as casein and whey, present in milk from human or non-human mammals, such as bovines (e.g. cows), goats, sheep or camels.

The term "gel" as used herein has its conventional meaning and refers to an aqueous system, which does not exhibit flow when in a steady state.

The term "microgel" as used herein has its conventional meaning and refers to particles of a gel, which particles have a volume/surface average particle diameter smaller than 100 μιη.

The term "protein" as used herein has its conventional meaning and refers to a linear polypeptide comprising at least 10 amino acid residues.

The term "milk" as used herein has its conventional meaning and refers to the liquid produced by the mammary glands of mammals, such as bovines (e.g. cows), goats, sheep or camels.

The term "cheese milk composition" as used herein refers to a liquid composition comprising dairy proteins, such as casein and whey proteins, in an amount and ratio suitable for making cheese.

The term "lipid' or "lipid particles" as used herein has its conventional meaning and refers to particles, including droplets and globules, of esters of glycerol and fatty acids, such as monoglycerides, diglycerides, triglycerides or a mixture thereof. In this regard it is noted that the terms lipid and fat are used interchangeably.

The term "coagulant" as used herein has its conventional meaning and refers to enzymes or agents able to specifically split the Phe-Met bond of κ-casein.

The term "water retaining particle" as used herein, refers to a particle comprising at least 75% by weight water and at least one water retaining agent, such as casein, whey proteins or alignate. The term "volume/surface average particle diameter ^' " as used herein has its conventional meaning and refers to the so called Sauter mean diameter (d ₃₂ ) determinable with light scattering, as amongst others mentioned in P. Walstra et al, Physical Chemistry of Foods, 2003.

DETAILED DESCRIPTION OF THE INVENTION

A first aspect of the present invention relates to a method for preparing hard or semi-hard type cheese, comprising the steps of:

a. providing a cheese milk composition, which composition comprises:

- 40 to 90% by weight water;

at least 2.5% by weight dairy proteins; and

at least 0.5 % by weight lipids;

b. letting the dairy proteins coagulate under the influence of a coagulant or acid, such that curd is formed;

c. forming a hard or semi-hard cheese from the curd;

wherein, in total at least 5% by weight of water retaining particles are added to the cheese milk composition and/or curd, which water retaining particles have a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μιη and wherein said water retaining particles comprise at least 75% by weight water, such that the cheese obtained comprises at least 50% by weight water, preferably at least 55% by weight water, more preferably at least 60% by weight water.

Due to the use of water retaining particles with the above mentioned water content and particle size distribution, it is possible to prepare cheese with a relatively high water content, whilst maintaining excellent textural properties.

Preferably, 15 to 50% by weight of the total amount of water is present in the cheese as water retaining particles, more preferably 18 to 50% by weight.

The cheeses prepared with the method of the present invention, comprise a high amount of water, of which a considerable part is present in the water retaining particles. Due to the fact that these particles are generally smaller than 20 μιη, they will not be noticed by consumers.

Furthermore, since these water retaining particles have a gel like texture, they contribute to the firmness of the cheese, which would not be the case if one would just increase the water content by adding additional (free) water to the cheese or the cheese milk.

The cheeses prepared with the method according to the present invention have the textural properties of a hard or semi-hard cheese, but have a water content which has not previously been reported for these types of cheeses. Due to the higher water content, less lipids may be used, or less protein may be used. This has an advantageous effect on the caloric value of the cheese and on the production costs.

Preferably, the water retaining particles used in the method of the present invention comprise at least 80% by weight water, more preferably 85% by weight water, even more preferably they comprise at least 90% by weight water, most preferably they comprise at least 95% by weight water.

The water retaining particles will comprise besides water also a water retaining agent, hence the water retaining particles will in general not comprise more than 99.9% by weight water.

The water retaining particles preferably have a volume/surface average particle diameter

(d ₃₂ ) of 1 to 20 μιη, wherein less than 10% of the particles have a volume/surface average particle diameter of more than 25 μιη.

It is advantageous to use relatively small water retaining particles for reasons that such particles are not noticed by consumers. In general, consumers will only notice individual particles in a food product when such particles are 25 μιη or larger.

Another advantage of the use of such relatively small water retaining particles is that they may be dispersed evenly throughout the cheese and may contribute to the texture of the cheese.

For making cheese, it is important that a considerable amount of the dairy proteins of the cheese milk composition is casein. Preferably, at least 80% by weight of the dairy proteins of the cheese milk composition of step a) is casein.

In the method of the present invention, different kinds of water retaining particles may be used. An important feature is of course that they are edible and that they are small enough to avoid that they are individually noticed by consumers.

Preferably, the water retaining particles used are microgel particles comprising:

- at least 0.5% by weight alginate, casein, whey protein or a combination thereof;

- at least 75% by weight water; and

having a volume surface average particle diameter (d ₃₂ ) of 1 to 20 μιη.

Alginate, casein and whey proteins are preferably used because they are already commonly used in food products and are not perceived negatively by consumers. Furthermore, they are excellent for binding water.

In a preferred embodiment of the present invention, the water retaining particles used in the present invention are alginate microgel particles, which comprise:

- 0.5 to 2% by weight alginate;

- at least 75% by weight water; and

wherein the microgel particles have a have a volume/surface average diameter (d ₃₂ ) of 1 to 20 μιη and an internal pH of 5 to 8. These particles are excellent water binders and are small enough not to be noticed by consumers, Furthermore, it is preferred that the pH of these particles when they are added to the cheese milk composition or curd is between 5 to 8, this way a negative influence on the pH of the cheese or on the taste of the cheese to be prepared is avoided. These kinds of alginate microgel particles have not been reported before.

Preferably, the alginate microgel particles have an internal pH of 6.5 to 7.5, preferably a pH of about 7.

The alginate microgel particles preferably have a volume/surface average diameter (d ₃₂ ) of 1 to 10 μιη.

Furthermore, the alginate microgel particles preferably comprise at least 85% by weight water, more preferably at least 90% by weight water, most preferably at least 95% by weight water.

These particles may be prepared and may be obtainable by the following method, which has not been reported before:

a. providing a dispersion, which dispersion comprises:

- 0.1 to lwt% of dispersed calcium carbonate (CaC03) particles having a

volume/average diameter (d ₃₂ ) of 0.2 to 20 μιη;

- and a continuous aqueous phase comprising 0.5 to 2 wt% alginate and 0.1 to 1 wt% glucono delta lactone (GDL);

b. emulsifying the dispersion of step a) in a continuous oil phase;

c. letting the emulsified droplets of the dispersion of step a) gel in the continuous oil phase, such that microgel particles are formed; and

d. separating the microgel particles from the oil phase.

In the dispersion of the above mentioned step a) the molar ratio of GDL to CaC0 ₃ ranges from 1.5 to 2.5, preferably from 1.9 to 2.1. Furthermore, the emulsion prepared in the above mentioned step b) preferably comprises 1 to 30% by weight of the dispersion of the above mentioned step a). In a preferred embodiment, in step c) the emulsion is stirred for 1 to 1500 minutes. With the above mentioned method it is thus possible to obtain alginate microgel particles which may be used in the method of the present invention.

The present invention thus also relates to alginate microgel particles obtainable by this method and to their use in hard-or semi-hard type cheese. The internal pH of said microgel particles ranges from pH 5 to 8, preferably pH 6.5 to 7.5.

Another type of water retaining particles to be used in the present invention may be based on a casein gel. These casein microgel particles preferably comprise:

- 0.5 to 15% by weight casein;

- at least 75% by weight water; and wherein the microgel particles have a volume surface/average diameter (d ₃₂ ) of 1 to 20 μιη and a pH of 5 to 8.

Preferably, the concentration calcium in the casein microgel is at least 0.1% by weight. This way a gel may be formed from the casein.

In a preferred embodiment of the present invention, the casein microgel particles comprise at least 75% by weight water and 2 to 15% by weight casein, preferably 8 to 10% by weight casein, most preferably about 9% by weight casein.

Preferably, at least a part of the casein of the microgel particles has been cross-linked by means of a heat-treatment, the addition of calcium, the addition of pyrophosphate and/or a treatment with a cross-linking enzyme, such as transglutaminase. Due to such a cross-linking of the casein molecules in the microgel a firm gel may be formed.

A method of making such particles and the microgel particles obtainable by such method has not been reported before.

A method for preparing such particles comprises the steps of:

a. providing a dairy protein composition comprising:

- 70 to 90% by weight water;

- 0.5 to 15% by weight casein;

b. disintegrating at least a part of the casein micelles of the protein composition by mixing the dairy protein composition with a calcium binding agent, a calcium chelating agent and/or by subjecting the dairy protein composition to an ultra- or microfiltration treatment;

c. forming under agitation a gel from the dairy protein composition by adding a

calcium salt to said composition, such that the concentration calcium is at least 0.1% by weight of the composition, such that micro gel particles are formed, which have a volume/surface average diameter (d ₃₂ ) of 1 to 20 μιη and comprise at least

75% by weight water.

In this method the calcium binding agent or calcium chelating agent is preferably citrate, phosphate, pyrophosphate polyphosphate, carbonate, ethylenediaminetetraacetic acid (EDTA) or a combination thereof.

The calcium salt used in step c) of the above mentioned method is preferably calcium chloride. Furthermore, the dairy protein composition of step a) of the method described above preferably comprises 0 to 5% by weight lipids. This protein composition may also comprise flavors and colorants. The temperature in steps a) to c) of the above mentioned method is preferably kept between 0°C and 100°C and is more preferably the same in all these steps. Agitation as referred to in step c) may be carried out by shearing, stirring, shaking or any other method known in the art. In an optional step, the microgel particles obtained in step c) are subjected to a cross- linking treatment, e.g. by means of a heat-treatment, the addition of calcium, the addition of pyrophosphate and/or by means of an enzymatic treatment, such as a treatment with transglutaminase .

Subsequent to step c), the microgel particles may be separated from the mixture.

In another embodiment of the method of the present invention, the water retaining particles are whey microgel particles, which particles comprise:

- 0.5 to 15% by weight whey protein particles;

- at least 85% by weight water; and

wherein the microgel particles have a volume/surface average diameter (d ₃₂ ) of 1 to 20 μιη.

A second aspect of the present invention relates to hard- or semi hard cheese obtainable by the method of the present invention, as described above.

A third aspect of the present invention relates to hard or semi-hard cheese comprising: - at least 20% by weight casein;

- less than 30% by weight lipids;

- at least 50% by weight water, wherein 15 to 50% by weight of the total amount of water is present in the cheese as water retaining particles, which particles have a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μιη and wherein said water retaining particles comprise at least 75% by weight water.

Preferably, the water retaining particles comprise at least 80% by weight water, more preferably 85% by weight water, even more preferably at least 90% by weight water, most preferably at least 95% by weight water.

The hard or semi-hard cheese according to the present invention preferably comprises 55% by weight water, more preferably at least 60% by weight water.

Preferably, 15 to 50% by weight of the total amount of water is present in the cheese as water retaining particles, more preferably 18 to 50% by weight.

In a preferred embodiment of the present invention the water retaining particles have a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μιη, and less than 10% of the particles have a volume/surface average particle diameter of more than 25 μιη.

Preferably, the water retaining particles are microgel particles comprising:

- at least 0.5% by weight alginate, casein, whey proteins or a combination thereof;

- at least 75% by weight water; and

having a volume/surface average particle diameter (d ₃₂ ) of 1 to 20 μιη.

In the hard of semi-hard cheese according to the present invention, the water retaining particles are preferably alginate microgel particles, which particles comprise: - 0.5 to 2% by weight alginate;

- at least 75% by weight water; and

wherein the microgel particles have a volume/surface average diameter (d ₃₂ ) of 0.1 to 20 μιη and an internal pH of 5 to 8.

These alginate microgel particles preferably have an internal pH of 6.5 to 7.5, preferably a pH of about 7.

However, in this regard it is noted that during maturation of the cheese, the microgel particles will ultimately obtain the pH of the rest of the cheese.

The alginate microgel particles have in a preferred embodiment of the present invention a volume/surface average diameter (d ₃₂ ) of 1 to 10 μιη, preferably 1 to 5 μιη.

Preferably, the alginate microgel particles comprise at least 80% by weight water, more preferably 85% by weight water, even more preferably at least 90% by weight water, most preferably at least 95% by weight water.

In another preferred embodiment of the hard and semi-hard cheese of the present invention, the water retaining particles are casein microgel particles, which particles comprise:

- 0.5 to 15% by weight casein;

- at least 75% by weight water; and

wherein the microgel particles have a volume/surface average diameter (d ₃₂ ) of 1 to 20 μιη and a pH of 5 to 8.

The concentration calcium in the casein microgel particles is preferably at least 0.1% by weight.

In a preferred embodiment of the present invention the casein microgel particles comprise at least 75% by weight water and 2 to 15% by weight casein, preferably 8 to 10% by weight casein, most preferably about 9% by weight casein.

Preferably, at least a part of the casein of the microgel particles has been cross-linked.

This cross-linking has preferably been achieved by means of a heat-treatment, the addition of calcium, the addition of pyrophosphate and/or or by means of a treatment with a cross-linking enzyme, such as transglutaminase.

In another preferred embodiment of the hard and semi-hard cheese of present invention, the water retaining particles are whey microgel particles, which particles comprise:

- 0.5 to 15% by weight whey protein particles;

- at least 85% by weight water; and

wherein the microgel particles have a volume/surface average diameter (d ₃₂ ) of 1 to 20 μιη.

Preferably, the whey microgel particles comprise at least 90% by weight water, more preferably 95% by weight water. A fourth aspect of the present invention relates to the use of the above mentioned water retaining particles in the preparation of cheese. The amount of water retaining particles is preferably chosen such that the cheese prepared comprises at least 50% by weight water. In such as cheese preferably 15 to 50% by weight of the water is provided by the water retaining particles.

The present invention will be illustrated further by means of the following non-limiting examples. EXAMPLES

Example 1 : preparation of alginate microgel particles

The alginate microgel particles were prepared through an emulsification/internal gelation technique. To this end dry CaC03 nanoparticles (with a CaC03/alginate mass ratio of 0.1/1) were dispersed in water and sonicated for 10 minutes using a Branson Sonifier 450 (output control level 5, duty cycle 50%), to allow complete dispersion of the nanoparticles. Sodium alginate (Algin Texturas from El Bulli, Spain) was added to obtain a ratio of 1 % (w/v) and the sample was stirred using a magnetic stirrer. After complete dissolution of the alginate, GDL was added (GDL/CaC03 mol ratio of 1.98/1) and the sample was stirred for 1 more minute. The mixture was then emulsified in volume ratios up to 30% in a continuous phase of medium chain triglyceride (MCT) oil, containing 2% (w/w) PGPR as surfactant. Emulsification was performed with an Ultra Turrax (IkaR 319 T25 digital) at 10,000 rpm for 10 minutes. The samples were mildly agitated for 8 hours using a magnetic stirrer to prevent sedimentation and clustering of the alginate droplets during gelation. All samples were kept in closed containers and stored in a refrigerator until further analyses. The microgel particles obtained had a water content of more than 80% by weight and the average particle diameter (d ₃₂ ) as measured with a Mastersizer 2000 (Malvern Instruments) equipped with a Hydro 2000G large volume automated sample dispersion unit was about 10 μιη.

Example 2: preparation of casein microgel particles

Skim milk protein concentrate (obtained after micro- and ultrafiltration of skim milk) containing 14.7% by weight milk protein (of which 13.5% by weight is casein) was diluted with water to a total milk protein concentration of 9.0% by weight (8.3% by weight casein), and 0.3% by weight sodium pyrophosphate and 3.5% by weight sodium citrate was added and stirred for 2 minutes. The mixture was added to a solution of calcium chloride (10% by weight) while stirring vigorously using a turrax for 2 minutes. Subsequently, the casein gel particles were left to precipitate. The particles were kept in the calcium chloride solution for 24 hours to increase the firmness of the particles. Next, the suspension with the particles was heated for five minutes at 85°C. After cooling, the particles were separated from the solution. The water content of the particles was 87% by weight and the average particle diameter (d ₃₂ ) as measured with a Mastersizer 2000 (Malvern Instruments) equipped with a Hydro 2000G large volume automated sample dispersion unit was about 15 μιη. Example 3 : preparation of whey microgel particles

Whey protein micro particles (MPs) were made by first dissolving whey protein isolate (WPI) (BIPRO, DAVISCO Food International Inc., Le Sueur, MN) in water to form a 40% w/w dispersion. The dispersion was stirred with an overhead mixer for at least 2 h at room temperature and then further mixed with a magnetic stirrer for at least 16 h at 4 °C. After that, the WPI dispersion was centrifuged at 1000 rpm for 10 min at 20 °C. Subsequently, the dispersion was placed in a bowl mixer (type W50) that was connected to a Brabender Do- corder E330 (Brabender OHG, Duisburg, Germany). At this moment heated samples were heated with water of 95 °C from a water bath. Within the mixer the dispersion was mixed for 5 min at 0 rpm, 5 min at 5 rpm and 40 min at 200 rpm. After mixing, the mixer was cooled with water of 4 °C for approximately 5 min and then the fresh MPs were taken out. The obtained fresh MPs were placed in a 50 °C oven (Termaks) for 2 days and then ground with an ultracentrifuge mill (Retsch ZM 1000). The mill had a 24-tooth stainless steel rotor to which an 80 μιη sieve was attached. The rotor was operated at 15,000 rpm for 120 s. After the grinding, standard MP were obtained.

To obtain different MP's, DTT was added in different amounts up to 40 mM to the 40% w/w WPI emulsion and mixed for 30 minutes at room temperature. The water holding capacity (WHC) of the MPs was measured by centrifuging a 10% w/w dispersion (Eppendorf centrifuge 5424, VSL, Delft, The Netherlands) at 3000 rpm for 20 min to form a pellet and a supernatant. The supernatant was decanted and the pellet was weighted. From the weight difference between the dry MPs (oven 24 h at 105 C) and the formed pellet the WHC (g water/g dry material) was calculated. WHC

• Material Concentration solution (g water/g dry material)

Unheated" Heated"

MPs 3.7 (± 0.2) 5.4 (± 0.5)

10 mM 5.4 (± 0.07) 6.8 (± 0.1)

MPs + DTT 20 mM 6.2 (± 0.2) 7.6 (± 0.2)

40 mM 7.4 (± 0.05) 11 (± 0.05)

From the figure and the table above it is clear that the reaction with DTT enhances water holding by the MP's. Water contents of the particles of over 90% could be obtained.

Example 4: preparation of a low fat semi-hard cheese A low fat (30+) semi hard cheese was made following a normal procedure as known by cheese makers. We started with 10 1 skimmed milk with 2.3% fat. Casein micro particles were prepared as described in example 2. The micro particles contained 9%w protein (mainly casein) and 87%w water. The average particle diameter (d ₃₂ ) was 15 μιη. Micro particles were added to the cheese milk before rennetting in different amounts: 5% (w/w) and 10%(w/w) of wet particles. From the curd we formed 4 small cheeses of 250-300 grams. After brining the cheeses were immediately wrapped in foil to avoid drying. The cheeses were stored at 14°C for 6 weeks. The addition of the micro particles resulted in an increased moisture content.

However, the texture of the cheese was not recognizable changed, it was not softer as is expected for a cheese with a higher moisture content.

In this example the alginate microgel particles according to the present invention were used in the preparation of fondue cheese, i.e. a semi hard type of cheese, with an increased water content. In this example two types of alginate microgel particles were used, namely relatively soft particles (0.50% alginate) and hard particles (1.25% alginate) prepared according to the method described in example 1.

Conventional fondue cheese was mixed at the lowest speed and heated to 60 ^° C with a

Thermomix for 1 minute. 5% Na-caseinate EM7, the alginate particles and/or water was added. Mixing was continued for 6 minutes at 60 ^° C. The melted cheese was immediately poured into plastic cups, cooled for 10 minutes at room temperature. The cup was capped and stored at 7 ^° C. The reference cheese composition (containing 5% EM7, no extra water) was 15.9 % fat, 18.6% protein, pH 5.72, 2.85% starch, and 54.4 % water. Other samples contained more water as such or added as alginate microgel particles. Cheeses were removed from the cup and a compression test with a Texture Analyzer (TA.XT plus) was performed. Strain Rate 1%/sec and a maximum strain of 70.0%. The force at 3 mm compression was used as a measure of the hardness of the cheese. For all samples this was within the linear response during compression. All measurements were done in triple. Results of cheese hardness (force at 3 mm compression) as a function of water content are shown in the Figure 1 below. With an increasing water content, the hardness of the cheese clearly decreased. When the water was added in the form of alginate microgel particles, the force needed to compress the cheese by 3 mm was higher than one would have expected.