The present invention relates to a phase separated dairy gel, wherein the dairy gel comprises a phase rich in lipid particles and protein, and a phase rich in a

depletant, such as polysaccharide ( s ) . The present

invention further relates to a method for preparing such a dairy gel, and its use in the preparation of dairy

products, preferably 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 .

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, all these substances have certain drawbacks. For example, crosslinked proteins are generally expensive and the addition of those protein particles to cheese has been found to lead to graininess. Furthermore, the use in cheese of substances foreign to it, such as inulin, are negatively perceived by consumers, as they undermine the natural image of cheese. Hence, a need exists for cheese having a low fat content, but with textural and functional properties comparable to that of full-fat cheese, and which cheese comprises only minimal amounts of expensive additional ingredients and ingredients foreign to cheese.

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.

A need also exists for dairy gels which are strong and have a lower fat content. Such dairy gels may be used for the preparation of cheese products, however, the may also be used for the preparation of other dairy products.

SUMMARY OF THE INVENTION

A first aspect of the present invention relates to a phase separated dairy gel, which dairy gel may be used for the preparation of gelled concentrated protein foods, in particular cheese or cheese like products.

The phase separated dairy gel according to the present invention comprises a phase rich in dairy proteins and lipids, and a phase rich in depletant, such as

polysaccharides, wherein the phase rich in dairy proteins and lipids comprises:

- at least 8% by weight dairy protein;

- at least 5% by weight lipid particles, which lipid particles have a volume/surface average diameter (d32)of 0.5 to 10 μπι;

- less than 0.05% by weight depletant;

- 40 to 90 % by weight water;

and wherein the phase rich in the depletant comprises:

- at least 0.1% by weight depletant;

- 80 to 99.9% by weight water; - less than 4% by weight dairy proteins;

- less than 4% by weight lipids.

A second aspect of the present invention relates to a method for preparing a phase separated dairy gel,

comprising the steps of:

i) preparing an aqueous mixture comprising:

- at least 7.0% by weight of a dairy protein;

- at least 4.5% by weight of lipid particles, which lipid particles have an volume/surface average diameter (d32) of 0.5 to 10 μπι;

- at least 0.05% by weight of a depletant; and

- 40 to 90% by weight water;

ii) letting the aqueous mixture at least partially

separate into a phase rich in dairy proteins and lipids, and a phase rich in depletant;

iii) forming a gel from the phase separated mixture, which gel comprises the phase rich in dairy protein and lipids, and the phase rich in depletant.

The phase separated dairy gel according to the present invention has an increased strength compared to similar non-phase separated dairy gels. This makes them

particularly useful for the preparation of cheese or cheese like products, in particular for the preparation of low-fat cheese products.

It is generally known that the presence of a

depletant, such as a polysaccharide, induces phase

separation of aqueous diary protein compositions. However, it has previously not been reported that due to the relatively high viscosity of the mixture used for

preparing the gel according to the present invention, only a microscopic phase separation of a phase rich in dairy proteins and lipids, and a phase rich in water and

depletant, such as polysaccharides occurs. Due to this microscopic phase separation, the dairy proteins are surprisingly able to form a relatively strong gel with a high water content.

Hence, it is possible to prepare from this gel dairy products such as cheese or cheese like products with a high moisture content, a lower fat content, and with excellent functional and textural properties.

A third aspect of the present invention relates to a phase separated dairy gel obtainable by the above

mentioned method.

A fourth aspect of the present invention relates to the use of the dairy gel according to the present

invention for the preparation of a dairy product, preferably a cheese product.

A fifth aspect of the present invention relates to a diary product, preferably a cheese product, comprising or prepared from the phase separated dairy gel according to the present invention.

A sixth aspect of the present invention relates to a cheese product comprising:

- at least 7.0% by weight dairy protein;

- at least 4.5% by weight lipid particles, which lipid particles have a volume/surface average diameter (d32)of 0.5 to 10 μπι;

- at least 0.05% by weight of a depletant;

- 40 to 90 % by weight water;

- an elastic modulus G' of 10 ⁴ - 10 ⁶ Pa.

DEFINITIONS The term "dairy protein" as used herein has its conventional meaning and refers to a protein, 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 "depletant" as used herein has its

conventional meaning and refers in the present invention to an agent which is chemically incompatible with casein and causes segregative phase-separation. In this regard reference is made to Walstra et al.,2003. Physical

chemistry of foods, pp. 163 ff..

The term "polysaccharide" as used herein has its conventional meaning and refers to carbohydrate molecules of at least ten monosaccharide units joined together by glycosidic bonds.

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 "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 throughout this specification.

The term "dairy gel" as used herein has its

conventional meaning and refers to a composition prepared from amongst others dairy proteins and for which the elastic storage modulus exceeds the loss modulus as measured by oscillatory shear rheology.

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 "volume/surface average particle diameter" as used herein has its conventional meaning and refers to the so called Sauter mean diameter (d32) determinable with light scattering, as amongst others mentioned in P.

Walstra et al . , Physical Chemistry of Foods, 2003.

The term "salting" as used herein has its

conventional meaning and refers to the addition of salt to curd or cheese and comprises brining, dry salting and rubbing of salt.

The term "brining" as used herein has its

conventional meaning and refers to the addition of salt to cheese or curd by means of at least partially immersing a block of curd or cheese in a concentrated salt solution (NaCl), such that salt is absorbed.

The term "dry salting" as used herein has its

conventional meaning and refers to the mixing of salt crystals (NaCl) with curd grains or curd pieces.

The term "rubbing" as used herein has its conventional meaning and refers to the rubbing of salt (NaCl) on the surface of a curd block or cheese. DETAILED DESCRIPTION OF THE INVENTION

A first aspect of the present invention relates to a phase separated dairy gel comprising a phase rich in dairy proteins and lipids, and a phase rich in depletant (e.g. a polysaccharide or mixture thereof) , wherein the phase rich in dairy proteins and lipids comprises:

- at least 8% by weight dairy protein;

- at least 5% by weight lipid particles, which lipid particles have a volume/surface average diameter (d32)of 0.5 to 10 μπι;

- less than 0.05% by weight depletant;

- 40 to 90 % by weight water;

and wherein the phase rich in depletant comprises;

- at least 0.1% by weight depletant; - 80 to 99.9% by weight water;

- less than 4% by weight dairy proteins;

- less than 4% by weight lipids.

Contrary to known dairy gels, the gel according to the present invention comprises separated phases. The

potential of such structures, for example in cheese making, in particular the preparation of hard or semi-hard cheeses, has not been recognized in previous reports. Up till now, it was generally accepted that phase-separation weakened gel strength (Food Hydrocolloids , 30 (2013) 333- 342) . In this regard reference is also made to the article of Perrechil et al . , in Food Hydrocolloids, 2009, wherein the use of locust bean gum in low pH caseinate gels has been described. Perrechilli et al . found that in non- macroscopically phase separated dairy gels (one-phase gels) the presence of LBG significantly dropped the stress and strain fracture values of the gels obtained.

The phase rich in depletant of the dairy gel

according to the present invention comprises preferably at least three times, preferably at least five times more depletant than the phase rich in dairy proteins.

Furthermore, the phase rich in dairy proteins preferably comprises at least five times, preferably at least ten times more dairy protein than the phase rich in depletant.

Preferably, the phase rich in depletant (e.g.

polysaccharides) is dispersed as micro phases throughout the phase rich in protein and lipids. Preferably, said micro phases have a volume/surface average diameter (d32) of less than 200 μπι. These micro phases of the phase rich in depletant preferably comprise, as referred to above, at least three times, more preferably at least five times more depletant than the phase rich in dairy proteins.

In another preferred embodiment, the dairy gel is a co-continuous structure of the phase rich in dairy protein and lipids, and the phase rich in depletant (e.g.

polysaccharides) .

The depletant used is preferably a polysaccharide or a combination of various kinds of polysaccharides. The polysaccharide used is preferably high methoxy pectin, alginate, Arabic gum, locust bean gum, kappa-carrageenan, lambda-carrageenan, iota-carrageenan, xanthan, methyl cellulose or carboxymethyl cellulose, dextran, gellan, guar, or a combination of any of these polysaccharides.

The phase separated dairy gel as a whole preferably comprises between 0.1 and 1% by weight of the depletant, which is preferably a polysaccharide.

Preferably, the dairy proteins present are suitable for preparing cheese, such as skim milk proteins or casein. Particularly for cheese it is preferred if the phase separated dairy gel as a whole comprises between 10 and 50% by weight dairy proteins, more preferably between 15 and 50% by weight dairy proteins.

The phase separated dairy product according to the present invention is preferably prepared in such a way that it is a hard or semi-hard cheese. Methods for preparing such cheeses are commonly known in the art.

On a weight basis, preferably at least 80% of the dairy protein is casein, preferably at least 90% is casein, more preferably at least 95% is casein. In a particularly preferred embodiment, which is particularly suitable for use in the preparation of cheese, the phase separated dairy gel as a whole comprises between 15 and 50% by weight casein.

The pH of the dairy gel according to the present invention is preferably between 5 and 7, which is a suitable pH of cheese products, in particular hard or semi-hard cheeses. At least a part of the dairy proteins of the gel according to the present invention are preferably

coagulated under the influence of an acid or coagulant such as rennet, in particular chymosin of animal,

microbial and/or vegetable origin.

In a preferred embodiment of the present invention the phase separated dairy gel according to the present invention is a hard or semi-hard cheese, such as a Gouda or Cheddar type cheese, which cheese comprises between 15 and 50% casein and a pH between 5 and 7. Furthermore, the dairy gel comprises between 0.1 and 1% by weight of said depletant, which is preferably a polysaccharide, such as locust bean gum. The phase rich in depletant comprises preferably at least three times, preferably at least five times more depletant than the phase rich in dairy

proteins. More preferably, the phase rich in depletant is dispersed as micro phases throughout the phase rich in protein and lipids. Preferably, said micro phases have a volume/surface average diameter (d32) of less than 200 μπι.

A second aspect of the present invention relates to a method for preparing a phase separated dairy gel

comprising the steps of:

i) preparing an aqueous mixture comprising:

- at least 7.0% by weight of a dairy protein;

- at least 4.5% by weight of lipid particles, which lipid particles have an volume/surface average diameter (d32) of 0.5 to 10 μπι;

- at least 0.05% by weight of a depletant; and

- 40 to 90% by weight water;

ii) letting the aqueous mixture at least partially

separate into a phase rich in dairy protein and lipids, and a phase rich in depletant;

iii) forming a gel from the phase separated mixture, which gel comprises the phase rich in dairy protein and lipids, and the phase rich in depletant.

Due to the presence of a depletant (e.g

polysaccharide) in the aqueous mixture of step i), phase separation occurs. However, due to the presence of the small lipid particles, or due to the high viscosity resulting from the relatively high protein concentration, a complete phase separation in two macroscopic,

substantially parallel extending phases does not occur.

Once in step ii) of the method of the present

invention the phase separation has partly or completely taken place, the phase separated mixture is in the

subsequent step iii) allowed to form a gel. This way, the phase separated system as obtained in step ii) is

stabilized.

The formation of a gel, as referred to in step iii) of the present method, may occur spontaneously or it may be induced by heating, cooling, lowering of the pH or by means of the addition of a coagulant, such as rennet, or by lowering the water content of the system. Depending on the way the formation of the gel is induced and depending on the composition of the aqueous mixture used, in

particular the amount of dairy protein and the amount of lipid particles, the formation of the gel will occur quickly or will be relatively slow. In this regard it is noted that the use of rennet for inducing gel formation is particularly preferred when the aim is to prepare a hard or semi-hard cheese, such as a Gouda or Cheddar type cheese .

Furthermore, if the formation of the gel is slow it is of importance that the concentration of dairy proteins and lipid particles is chosen such that during the

formation of the gel, the already partially phase

separated mixture does not in the meantime phase-separate macroscopically, i.e. to such an extent that the phase separation becomes visible to the naked eye. The rate of phase separation can be slowed down by using a dairy protein concentration, preferably a casein concentration, in the aqueous mixture of step i) of more than 10% by weight .

Without wishing to be bound by any theory it is assumed that during the phase separation the lipid

particles accumulate (jam) in the phase rich in dairy protein and lipids stop or at least considerably slow down the phase separation. This way a structure is obtained which is not macroscopically phase separated, but which has only phase separated microscopically, i.e. the phase separation is not visible with the naked eye. This is advantageous for reasons that in such a microscopically phase-separated system the dairy proteins (particularly casein) and lipid particles are organized in a packed system before coagulation. As a result, after coagulation (e.g. renneting) rearrangement of the gel is more

difficult and a reduction of syneresis is observed. Hence, the gel formed has a relatively high water content.

Moreover, it is assumed that the closely packed fat particles contribute to the strength of the renneted gel more than they would do in an ordinary, non-phase

separated coagulated (e.g renneted) gel. With the method of the present invention it is thus possible to prepare a dairy gel, and cheese, with an exceptional combination of strength, water content and lipid content.

Preferably, the aqueous mixture according to claim 1 comprises between 0.1 and 1% by weight depletant. The depletant used is preferably a polysaccharide, which is preferably chosen from high methoxy pectin, alginate, Arabic gum, locust bean gum, kappa-carrageenan, lambda- carrageenan, iota-carrageenan, xanthan, methyl cellulose or carboxymethyl cellulose, dextran, gellan, guar, or a combination of any of these polysaccharides.

The aqueous mixture of step i) preferably comprises between 10 and 50% by weight, more preferably between 15 and 50% by weight dairy proteins, even more preferably between 15 to 35% by weight dairy protein, even more preferably 15 to 25% by weight, most preferably 15 to 20% by weight dairy protein. In a preferred embodiment, which is particularly suitable for preparing cheese, in

particular hard or semi-hard cheese, the aqueous mixture of step i) comprises between 15 to 50% by weight casein.

In a preferred embodiment of the present invention, the concentration casein in the aqueous mixture of step i) is higher than 20% by weight. Upon cooling, such a mixture will spontaneously form a gel. Hence, no use has to be made of additives such as coagulants or acids.

Furthermore, if the skilled person chooses the

concentration of lipids in the aqueous mixture of step i) such that after the incubation of step ii) the fraction of lipid particles in the phase rich in dairy protein and lipids exceeds 50% by weight, preferably exceeds 55% by weight, a gel will also spontaneously form.

On a weight basis preferably at least 80% of the dairy protein is casein, preferably at least 90% is casein, more preferably at least 95% is casein.

On a weight basis, the dairy protein to water ratio in the aqueous mixture of step i) is preferably higher than 0.09, preferably higher than 0.1, more preferably higher than 0.2.

Due to the fact that the dairy protein and lipid particles are concentrated into one phase, the strength of the dairy gel, as given by the elastic shear modulus G' (Walstra et al . , Dairy Science and Technology, 2006.), prepared according to the method of the present invention is considerably stronger than a gel wherein such

microscopical phase separation has not taken place. This means that the skilled person will be able to incorporate more water into the gel while maintaining sufficient strength of the gel.

Since the gel prepared according to the method of the present invention has a relatively high water content and an excellent strength it is possible to prepare mature or unmatured cheeses thereof, preferably hard or semi-hard cheeses, which cheeses have a relatively high water content compared to the same kind of cheeses which have been prepared in a traditional way, i.e. without the microphase-separated protein/lipid-depletant structure. Consequently, the amount of fat in the cheese is lower than in conventional cheese, without reducing the textural properties of such a cheese.

In order to prepare cheese, preferably hard or semi ^¬ hard cheese, from the gel prepared by the method of the present invention, starter cultures of lactic acid

bacteria are added to the aqueous mixture of step i) or to the phase separated mixture of step ii) . Furthermore, a coagulant, such as rennet, may be added to the aqueous mixture of step i) or the phase separated mixture of step ii) . If the coagulant is added to the aqueous mixture of step i), it is preferred to carry out step i) and/or ii) at a temperature below 20°C such that the coagulant (e.g. rennet) is not active. After step ii) the temperature may be increased to allow the coagulant to form a gel.

After the aqueous mixture has gelled, whey may be drained from the gel such that curd is obtained. However, depending on the composition of the aqueous mixture, it may not be necessary to drain any whey from the gel, such that the gel obtained in step iii) should be considered to be curd. In any case, the curd obtained may be allowed to mature, such that ripened cheese is formed, such as hard or semi-hard cheeses, such as a Gouda-type cheese or a Cheddar type cheese. Typically, the gel of step iii) will be subjected to a salting treatment, such as brining, and to a step of storing, such that a hard or semi-hard cheese is formed. However, it may also be possible to prepare a so called fresh cheese from the curd obtained. Methods for preparing mature and un-matured cheese from curd are commonly known by the person skilled in the art; in this regard reference is made to Walstra et al . , 2006, Dairy Science and Technology. In view of these cheese

applications, the pH of the gel formed in step iii) is preferably between 5 and 7.

In a preferred embodiment of the present invention the amounts of protein, lipid, water and depletant in the aqueous mixture of step i) are chosen such that in step ii) of the method of present invention a co-continuous structure of a phase rich in dairy proteins and lipids, and a phase rich in depletant (e.g. a polysaccharide) is formed. The preparation of such a co-continuous structure is advantageous for reasons that in such a structure, the dairy proteins present in the aqueous mixture have been concentrated maximally into the (continuous) phase rich in dairy proteins. The gel and subsequent cheese prepared from such structures have a maximal strength.

Alternatively, the amount of protein, lipid, water and depletant (e.g. polysaccharide) may be chosen such that the phase rich in depletant becomes dispersed in the phase rich in protein and lipids. If such a dispersion is not automatically formed, it may be advantageous to actively disperse the phase rich in depletant into the phase rich in dairy protein and lipids. In general, various methods can be used by the skilled person for preparing such dispersions .

These dispersions may be formulated such that the phase rich in depletant (e.g. a polysaccharide) is dispersed as micro phases throughout the phase rich in protein and lipids. These micro phases preferably have a volume/surface average diameter (d32) of less than 200 μπι. The phase rich in dairy proteins and lipids forms in such a case the continuous phase. In this regard it is noted that the skilled person will appreciate that for the determination of relatively large particles (i.e. larger than 10 μπι) static light scattering is more suitable, whereas for smaller particles (i.e. smaller than 10 μπι) dynamic light scattering will be more suitable.

In the phase rich in depletant (e.g. polysaccharide), the concentration depletant is preferably at least two times, preferably at least three times, more preferably at least four times as high as the concentration depletant in the aqueous mixture of step i) of the method of the present invention. Hence, a considerable amount of depletant has accumulated in this phase.

It is further preferred that in the phase rich in dairy protein and lipids the concentration of protein is at least two times, preferably at least three times, more preferably at least four times and most preferably at least five times as high as the concentration of protein in the aqueous mixture of step i) . Hence, a considerable amount of dairy protein, preferably casein, has

accumulated in this phase. Due to the relatively high amount of protein in this phase it is possible to form a relatively strong protein gel, wherein the depletant rich phase is contained. Such a strong gel is particularly suitable for preparing cheese.

The aqueous mixture of step i) alternatively comprises 10 to 35% by weight dairy protein, preferably 20 to 30% by weight.

The aqueous mixture of step i) of the method of present invention preferably comprises 5 to 40% by weight lipid particles, preferably 10 to 25% by weight lipid particles. The lipid particles preferably have a

volume/surface average diameter (d32) of 0.5 to 5 μπι, more preferably 0.5 to 2 μπι.

Furthermore, the aqueous mixture of step i)

alternatively comprises 0.05 to 1% by weight depletant, preferably 0.05 to 0.5% by weight, most preferably 0.05 to 0.1% by weight .

Most preferably, polysaccharides are used as the depletant. The depletant may comprise one kind of

polysaccharide or may comprise a mixture of various kinds of polysaccharides.

The polysaccharides used are preferably chosen from high methoxy pectin, alginate, Arabic gum, locust bean gum (LBG) , kappa-carrageenan, lambda-carrageenan, iota- carrageenan, xanthan, methyl cellulose or carboxymethyl cellulose, dextran, gellan, kefiran, guar or a combination of any of these polysaccharides.

Preferably, the polysaccharides have been produced by bacteria that are normally used in the production of dairy products, such as microorganisms of the genera

Enterococcus , Lactobacillus, Lactococcus, Leuconostoc and Streptococcus. This way it is avoided that ingredients are used which are foreign to dairy products.

The aqueous mixture of step i) conveniently comprises 40 to 60% by weight water. More preferably, the mixture of step i) comprises 40 to 50% by weight water.

After preparing the aqueous mixture of step i), the mixture is left to phase-separate. During this phase separation, micro-phases of the separated phases will form. However, due to the relatively high amount of lipid particles, the phase separation stops before macro-phases become visible, i.e. phase separation observable by the naked eye. Roughly speaking this means that the domains formed by the phase-separation have a volume/surface average diameter (d32) of 200 μπι or less.

The mixture of step i) is generally left to phase separate for 1 to 180 minutes, preferably for 1 to 90 minutes, more preferably for 1 to 30 minutes. The

temperature at which the mixture is left to phase separate is generally from 0 to 60°C, preferably from 5 to 40°C, more preferably from 20 to 30°C. In a preferred embodiment of the method of the present invention, the mixture of step i) is in step ii) left to phase separate for 1 to 30 minutes at a temperature of 20 to 40°C.

After the phase separation has at least partially taken place, the phase separated mixture obtained in step ii) of the method of the present invention is allowed to form a gel.

Such a gel may form spontaneously, if the amounts of protein, lipid particles, depletant and water are chosen such that the fraction of the lipid particles in the phase rich in dairy protein and lipids exceeds 50% by weight, preferably exceeds 55% by weight and/or the dairy protein concentration in the aqueous mixture of step i) exceeds 20% by weight.

It is preferred to use a coagulant for allowing the dairy protein particles, such as casein, to aggregate and form a gel. Preferably, rennet is used, more preferably chymosin of animal, microbial and/or vegetable origin. Besides a coagulant, an acid such as lactic acid or glucono delta lactone may also be used to initiate the aggregation of the dairy proteins. Optionally the

coagulant may be added in step i), however in such a case it is important that the coagulant does not substantially reduce the microscopical phase-separation.

After the coagulant has been added to the phase separated mixture, some whey may be drained from the gel obtained, such that curd is formed. This curd may be used for preparing fresh cheese or for preparing matured cheese, such as Gouda type cheese of Cheddar type cheese. For preparing cheese from the curd, methods commonly known in the art may be used.

A third aspect of the present invention relates to a phase separated dairy gel obtainable by the method as described above. This dairy gel may, as mentioned above, be used for the preparation of dairy products, in

particular for the preparation of cheese. The dairy gel preferably comprises a phase rich in depletant present as micro phases in a phase rich in dairy proteins, wherein the micro phases have a volume/average diameter (d32) of less than 200μπι and wherein said phases rich in depletant preferably comprise at least three times, preferably at least five times more depletant than the phase rich in dairy proteins.

A fourth aspect of the present invention relates to a diary product, in particular a cheese product, comprising the phase separated dairy gel as described above, or a cheese product prepared from such a dairy gel.

A fifth aspect of the present invention relates to the use of a phase separated dairy gel as described above for the preparation of a dairy product, in particular cheese.

Depending on the composition of the dairy gel, or the aqueous solution used for preparing the gel and the further processing of the curd different kinds of cheeses may be prepared, such as fresh cheese, hard or semi-hard cheese , such as Gouda like cheese and Cheddar like cheese . A further aspect of the present invention relates a to cheese comprising:

- at least 25% by weight dairy protein;

- at least 8 wt% lipid particles, which lipid particles have a volume/surface average diameter (d32) of 0.5 to 10 μπι;

- at least 0.05% by weight of a depletant;

- 40 to 90 % by weight water;

- an elastic modulus G' of 10 ⁴ - 10 ⁶ Pa.

The cheese of the present invention has a water content which is exceptionally high for cheese, whereas the elastic modulus falls within the traditional range for cheese. In other words, the cheese of the present

invention has a relatively high water content, but its texture is comparable to traditional cheese. This makes it for example possible that less fat is present in the cheese, without reducing its textural properties. In general, the water to dairy protein ratio of the cheese prepared from the gel is on or above 0.8. Preferably, the ratio is higher than 1, preferably higher than 1.5, most preferably higher than 2.

The depletant used is preferably a polysaccharide or a mixture of different polysaccharides, as referred to above. The cheese product according to the present

invention preferably comprises between 0.1 and 1 % by weight of the depletant, preferably a polysaccharide or mixture thereof.

Furthermore, the cheese product according to the present invention is preferably a hard or semi-hard cheese, such as a Gouda type cheese or a Cheddar type cheese .

The elastic modulus (G' ) is measured by means of a controlled strain rheometer (MCR300 from PaarPhysica) in oscillatory shear with cone-plate geometry (75mm diameter, angle 1°, truncation 50 μπι) with an amplitude of 0.2% and a frequency of 1 Hz and generally lies between 10 ⁴ and 10 ^e Pa. Preferably, the cheese of the present invention has an elastic modulus which is comparable to hard- and semi-hard cheeses. Typically, the elastic modulus will for such types of cheese range from 10 ⁴ to 10 ⁶ Pa, furthermore the water content of the hard- and semi hard cheese of the present invention will range from 40 to 50% by weight. The present invention will be illustrated further by means of the following non-limiting Examples.

EXAMPLE S Example 1

Preparation of locust bean gum solution

0.5% and 1% by weight locust bean gum (LBG) solutions were prepared by dispersing respectively lg or 2g of LBG in 199 g water or 198 g of water at 70°C, respectively, while stirring for 30 minutes.

Preparation of 40% SMP solution

Skim milk powder (SMP) solution (40% by weight) was prepared by dispersing 100 g of the SMP powder in 150 g of water at 40°C while stirring for 30 minutes. The

composition of the skim milk powder was as follows:

Agglomerated skimmed milk powder

moisture < 4 wt.%

Fat (lipid) Max. 1.2 wt.%

Proteins 37.8 wt.%

Lactose 50 wt.% Fats

Use was made of cow butter fat, which contained less than 4% by weight water. Before use, the butter fat was heated to 60°C such that it fully melted.

Preparation of the samples

The samples of the aqueous mixture of the present

invention were prepared at room temperature by first emulsifying fats in the SMP solution before adding the LBG. This way, the fat droplet size was kept constant. The emulsification step was carried out by an Ultra-Turrax mixing apparatus leading to a volume/surface average diameter (d32) of around 2 micron. In order to remove any air bubbles present, the mixture was centrifuged (300g, for 5 minutes) . Subsequently, the mixture was allowed to phase separate for 15 minutes at 20°C, and thereafter the mixture was examined. Microscopical judgment of the LBG comprising samples clearly showed the occurrence of microphase-separation . However, as viewed by the naked eye, no phase separation was visible.

The following aqueous mixtures were prepared:

Table 1 : samples

Number a a a a

o o o o

Lipids LBG SMP water

1 10 0.4 20 69.6

2 30 0.2 20 49.8

3 10 0.2 28 61.8

4 17 0.27 22.8 59.93

comparative 0 0 40 60

experiment 15 g of these mixtures were gelled in plastic tubes by adding calf rennet (2.5g/12L), potency 1: 15,000), and calcium chloride (lg/L,) and subsequently keeping the samples in a water bath for 1 hour at 40°C. After

gelation, the samples were kept in the fridge at 10°C, and their elastic modulus, which is a measure of the firmness of the gel obtained, was measured.

In order to determine the effect of phase separation, comparative experiments were carried out with mixtures comprising the lipids, SMP and water contents as described above in Table 1, however with the exception that no LBG was added. Characterization of the samples

The size distribution of the lipid particles was

determined by using a Malvern Mastersizer 2000. In all samples the volume/surface average diameter (d32) was around 2μπι.

The elastic modus (G' ) of the gelled samples was measured using a controlled strain rheometer (MCR300 from

PaarPhysica) in oscillatory shear with cone-plate geometry (75mm diameter, angle 1°, truncation 50 μπι) with an amplitude of 0.2% and a frequency of 1 Hz.

Results

Table 2: Elastic modulus of the gelled sampl

Number Elastic

Modulus G' (Pa)

comparative 100 experiment

Examples (with phase-separation)

1 3000

2 24000

3 9000

4 9000

comparative experiments (i.e without

addition of LBG)

1 270

2 3000

3 500

4 1700

From Table 2 it is clear that the gels prepared from mixtures comprising LBG, i.e. the microphase-separated samples, are considerably stronger than the gels which have been prepared form mixtures which did not comprise LBG. This means that gels according to the present invention may comprise significantly more water than gels without depletant, e.g. polysaccharides (such as LBG) with the same strength (G' ) . This makes them ideal for

preparing cheese with a lower fat content.

Confocal Scanning Laser Microscope (CSLM) images of the gelled structures given in Figure 1 show that the phase- separated structures, also after renneting, are clearly different from the non-phase-separated structures.

Example 2 A concentrated dairy product containing around 19% protein (of which at least 90% casein) and around 10% milk fat was prepared via filtration. To one part of the product, which was heated to 50°C, 0.2% of LBG was added. The product was stirred for 60 min at 50°C to let the LBG dissolve. As a reference, another part of the product was given the same heat and stirring treatment. Subsequently, the samples were renneted with calf rennet at 40°C for half an hour. Microscopical examination showed a microscopical phase-separation (see Figure 1), which could not be observed by the naked eye. The strength of the renneted samples was determined by measuring the so-called Stevens value using a texture analyser. Cylindrical samples with a height of 45 mm and a diameter of 20 mm were compressed 5 mm at a rate of 1 mm/s and the maximum force during compression was recorded. Results are given in Table 3.

Table 3. Compression force of renneted concentrated dairy products .

Table 3 shows that producing a gel from a dairy product according to the present invention (i.e. wherein in the presence of a depletant, e . g . polysaccharide (LBG), microphase separation has occurred, stronger gels are formed .

Example 3

A concentrated dairy product containing around 19% protein (of which at least 90% casein) and around 10% milk fat was prepared via filtration. This product was diluted in a 70:30 weight ratio either with water (comparative

experiment) or with a 0.7% LBG solution (example according to the invention) . 2.5 g/ 12L of rennet was added to 30 gram of both samples after which the samples were left to gel for 1 hour at 40°C. Microscopic observation using CSLM and applying dyes to dye the protein, fat and LBG

confirmed that the gelled sample containing LBG had a microscopically phase-separated structure. Subsequently the samples were cut with a knife into about 1 cm ³ cubes and the samples were centrifuged for 4 hours at lO.OOOg which led to expulsion of whey. This decreased the water/casein ratio to 2.1 (comparative experiment, corresponds with 42% dry matter, 28% protein) or 1.6

(example according to the invention, corresponds with 49%, 32% protein) . From the samples a 5 mm thick slice was cut and this was analyzed using a rheometer (MCR 501 from PaarPhysica) . The elastic modulus of the samples was comparable at around 10 ⁵ Pa. This shows that by applying microscopic phase-separation the water content of gelled dairy products can be enhanced without lowering the strength of the product.

In a separate rheology experiment, a strain sweep (0.01%- 100%) was conducted at 5 rad/s and IN normal force.

Temperature was kept at 10 °C. The Serrated plate geometry (PP25/P2, diameter 25 mm) in oscillatory shear was used. To assure full contact between plates and sample a

specific loading procedure was applied, which means loading very slow until the normal force reaches IN and then lowering the gap for an extra 2%. Large amplitude oscillatory shear (LAOS) analysis was used to study nonlinear viscoelastic properties of gels. In a LAOS test, the cyclic variation of stress and strain was plotted against each other, also called Lissajous plots, such the hardening ratio could be determined according to

Hardening ratio (H) = (G _R - G _M ) / G _R .

In Figure 1, the hardening ratios of the samples was plotted as a function of the applied strain amplitude for the different samples of this example. The Figure shows that the phase-separated variant of example 3, which is a 30+ variant, closely resembles the behavior of a full fat cheese, whereas the comparative example behaves much more like a traditional low fat cheeses.

Analysis of the degree of phase separation of example according to the present invention

The CSLM image of the example according to the present invention was split up into the different signals, namely one for LBG and one for protein. Of both signals the intensity inside and outside the protein or LBG rich domains was measured. The obtained ratio gives an

indication of the ratio between the concentration inside and outside the domains. For the LBG it was found that the concentration inside the enriched LBG rich domains is 3 times higher than outside the LBG rich domains. For the protein it was found that the protein concentration inside the protein rich domains is 10 times higher than the than outside the protein rich domains.