Field of the invention

The invention relates to a process for making a Dutch- or Swiss-type cheese or cheese product, to the cheese so made, to the cheese per se, and to the use of certain casein sources to make these cheeses.

Background of the invention

Dairy products are made from animal milk and therefore are considered healthy and nutritious. Cheeses are amongst such dairy products and this invention is about Dutch- and Swiss-type cheeses.

Dutch- and Swiss-type cheeses are widely known and are

manufactured using traditional cheese making processes which include standardizing raw milk to cheese milk, curd formation, separation of the whey from the curd, and further treatment of the curd to the final product, employing steps such as pressing, brining and ripening. The final cheeses are products in which a fine balance of texture and taste has been achieved through processes which to a significant extent are still unknown, especially where the biochemical processes are concerned.

The past decades have seen proposals for changes to the manufacturing process of cheese. At the same time, though, it can easily be imagined that manufacturers are reluctant to consider any changes for fear of jeopardizing their product’s qualities, such as texture and taste.

One proposal for change is coagulating milk protein- containing compositions from which a portion of the water and sometimes also the whey proteins have been removed by microfiltration. Starting from milk one prepares a retentate, or concentrated composition, that is used to make a“pre-cheese” which is directly converted into cheese without laborious and costly separation steps to recover the curd. WO 98/10661 A describes such a cheese making method utilizing two distinct acid-forming fermentation steps. Cheese milk is microfiltered, partially fermented, evaporated, and further fermented and coagulated.

Another such method is described in WO 2012/110706 A which teaches to microfilter raw milk, pre-acidify it, and evaporate the pre-acidified casein concentrate to produce a so-called“pre-cheese” which is then processed to the cheese product. In this publication it is explained that the pre-acidification is necessary to reduce, or restrain increase of, the viscosity of the casein-containing streams. The reason for this undoubtedly is that the casein-containing streams still contain all the ingredients of the raw milk including the cream or— after partial skimming— part of the cream.

This pre-acidification in the process of WO 2012/110706 A, however, is disadvantageous because it entails the risk of premature coagulation, given the inherent variability of starter cultures in case starter cultures are used, and the risk of local over- acidification and coagulation in case chemical acidification is used. Another disadvantage of this prior art process is that the fat content of the final cheese product is necessarily related to the extent of skimming of the raw milk material that is subjected to microfiltration. These factors make that the process of WO 2012/110706 A is cumbersome.

The problem underlying the present invention is to overcome the disadvantages associated with the process described in WO 2012/110706 A.

The crux of the invention lies in a two-fold finding. One is that the inventors discovered that for cheese making it is possible to use casein sources made by microfiltration of milk that contains no or only a very small amount of fat. As a result, viscosity levels during the preparation of these casein sources remain low and concentrated casein-containing streams made therefrom need not be pre-acidified and can be handled easily. The other finding is that this casein source can be combined with a fat source which is not the fat as it is present in raw milk or retained during the microfiltration and evaporation steps as taught in WO 2012/110706 A. The fat that is used in the process according to the invention is fat that has been isolated from its natural environment. Fats like anhydrous milk fat and butter no longer possess the globule membrane that surrounds them in natural milk. Similarly, vegetable fats do not possess such a membrane either.

It has surprisingly been found that cheese making from these casein and fat sources does not impair the quality of the cheeses when made in accordance with the invention process.

Summary of the invention

Accordingly, the present invention relates to a process for the preparation of a Dutch- or Swiss-type cheese or cheese product comprising the steps of first preparing a pre-cheese from a concentrated protein source and a specific fat source followed by processing the pre-cheese obtained to the cheese or cheese product.

Detailed description of the invention

More specifically, the process to which the invention relates comprises a) providing a pre-cheese comprising, based on the weight of the pre-cheese,

15-36 wt.% of protein comprising, based on total weight of protein, at least 50 wt% of casein which casein is provided by a casein source that contains, based on dry weight, 60 wt.% or more of casein; and 15-36 wt.% of fat selected from anhydrous milk fat, an anhydrous milk fat fraction, butter, butter oil, and a vegetable fat;

b) processing the pre-cheese to the cheese or cheese product.

The protein used to make the pre-cheese must contain at least 50 wt% of casein. Other proteins, such as whey protein, may also be present. It is preferred that, based on the total weight of protein in the pre-cheese, 60 to 100 wt.% is in the form of casein, more preferably 70 to 100 wt.%. The casein is provided by a casein source that may come from bovine milk, buffalo milk, goat milk or sheep milk, but preferably comes from bovine milk. Generally, the casein source can be prepared from skimmed milk using filtration processes known in the art. Suitable casein sources are commercially available and include products that are known as micellar casein isolate (MCI) and milk protein concentrate (MPC), but other names are also used such as micellar casein concentrate, microfiltered milk protein concentrate, phosphocaseinate and native phosphocaseinate. In addition, Huppertz et al., International Dairy Journal, 74, pp. 1-11 (2017) teach that casein micelles may be formed from sodium caseinate. In a preferred embodiment the casein source is the only protein source in the pre cheese.

The casein source may contain whey protein in a caseimwhey protein weight ratio of about 4:1— as in raw milk - or higher. Preferred casein sources contain casein and whey protein in an amount such that the caseimwhey protein weight ratio is 8:1 or higher. MPC belongs to the former, MCI to both the former and the latter. MCI protein sources are preferred.

The content of casein in the casein source is 60 wt.% or higher, based on total weight of dry matter in the casein source, preferably at least 70 wt.%. Very good results have been achieved with casein sources having a casein content between 70 and 85 wt%, based on total weight of dry matter. The use of MCI is, accordingly, preferred over the use of MPC. For example, if the casein source is prepared from powder, it will be used in the form of a suspension in an aqueous medium, suitably water. To this end, the powder can be suspended in water (or some other aqueous medium such as a suitable salt solution) and the suspension evaporated until the required casein content has been reached. Such

concentration can take place without the need for acidification such as taught in prior art teachings such as aforementioned WO 2012/110706 A. Another possibility is to start from an aqueous protein (with high casein content) suspension having a protein content of less than 20 wt.% based on total weight of the suspension and then add powdered casein source to reach the desired solids content.

The fat used to make the pre-cheese is selected from anhydrous milk fat (AMF), an anhydrous milk fat fraction made from anhydrous milk fat, butter, butter oil, and a vegetable fat. The dairy-based fats may come from bovine milk, buffalo milk, sheep milk or goat milk, bovine milk being preferred. The preferred fat is AMF isolated from bovine milk. Preferred vegetable fats are rapeseed oil, sunflower oil and soy bean oil. Fractions made from AMF are known. See, for instance, Van Aken et al., JAOCS 76, no. 11, 1323-1331 (1999). Which fraction to use for the process according to the invention will depend on the properties of the cheese one wishes to make. In general, the relative amounts of dairy fat and vegetable fat are such that the majority of the fat (>50 wt.% based on total weight of fat) is dairy-based fat.

Next to the protein and the fat, the pre-cheese may be provided with other desirable components such as starches, flavors, colorants, herbs, spices, vitamins, and salts.

In step (a) of the process according to the invention the pre-cheese is provided. This can be achieved in different ways as will be apparent to the skilled person. It was, however, found particularly preferred that step (a) comprises providing a suspension of the protein in water, and mixing the fat therein using high shear mixing. More specifically, in a preferred embodiment step (a) of the present process comprises the steps of

(i) providing an aqueous suspension of a suitable casein-rich protein source, i.e. a protein source which comprises, based on dry matter, at least 60 wt%, preferably at least 70 wt.%, and more preferably between 70 and 85 wt.% of casein;

(ii) heating the aqueous suspension obtained in step (i) to a temperature above the melting temperature of the fat source to be used in step (iii);

(iii) preparing a fat-in- water emulsion by

A. adding a fat source;

B. optionally adding additional casein-rich protein powder, either separate from or simultaneously with the fat source; and

C. emulsifying the mixture into a fat-in-water emulsion;

in any order provided step (iii) C always takes place after step (iii)A; and

(iv) cooling the fat-in-water emulsion to obtain the pre-cheese.

In steps (i) and (iii) the different components are obviously added in such amounts as to arrive at the required contents of protein, casein and fat in the pre-cheese as defined herein, i.e. in the range of 15 to 36 wt.% of protein and in the range of 15 to 36 wt.% of appropriate fat, the weight percentages for protein and fat being based on total weight of the pre-cheese. Step (ii) could also be carried out after addition of the fat source in step (iii). In such a case the fat source is suitably added in the form of small pieces, so that it melts more easily when the temperature of the mixture is raised to above its melting temperature.

For example, in one suitable embodiment the pre-cheese is made by the successive steps of

(i) providing a suspension of the casein-rich protein in water having a total solids content in the range of 25 to 45 wt.%, preferably 27 to 43 wt.%, most preferably 28 to 41 wt%;

(ii) heating the suspension to a temperature above the melting temperature of the fat;

(iii) A. adding the fat, suitably in liquid form, to the heated suspension;

C. mixing the fat and the suspension to obtain a fat-in-water emulsion; and

(iv) cooling the fat-in-water emulsion to obtain the pre-cheese.

In another exemplary embodiment step (a) comprises the successive steps of

(i) providing a suspension of the casein-rich protein in water having a total solids content below 25 wt.%;

(ii) heating the suspension to a temperature above the melting temperature of the fat;

(iii) A. adding the fat, suitably in liquid form, to the heated suspension;

C. mixing the fat and the suspension to obtain a fat-in-water emulsion;

B. adding casein-rich protein powder whilst mixing, in such amount to obtain a fat-in- water emulsion having a total solids content in the range of 25 to 45 wt.% .%, preferably 27 to 43 wt.%, most preferably 28 to 41 wt%; and

(iv) cooling the resulting fat-in-water emulsion to obtain the pre-cheese.

In yet another embodiment step (a) comprises the successive steps of

(i) providing a suspension of the casein-rich protein in water having a total solids content below 25 wt.%;

(ii) heating the suspension to a temperature above the melting temperature of the fat;

(iii) A./B. suspend casein-rich protein powder in liquid fat and adding the

resulting MCI-in-fat suspension to the heated protein suspension; C. mixing to obtain a fat-in-water emulsion having a total solids content in the range of 25 to 45 wt.% .%, preferably 27 to 43 wt.%, most preferably 28 to 41 wt%; and

(iv) cooling the resulting fat-in-water emulsion to obtain the pre-cheese.

Preparation of the pre-cheese suitably starts from an aqueous suspension of the casein-rich protein source as also indicated above. Suitable protein compositions have been described hereinbefore. Many commercial MPC and MCI products are available as powders with low (less than 5 wt%) water content. Such powders could suitably be used for providing the aqueous protein suspension in step (i). Alternatively, aqueous protein suspensions with a total solids content in the order of 15-20 wt% based on total weight of the suspension could be used as starting material, Such suspension would typically be obtained after membrane filtration in a process for preparing MPC or MCI powder. For the purpose of the present invention it was found particularly suitable to use a suspension of the protein in water having a total solids content in the range of 25 to 45 wt.%, preferably 27 to 43 wt.%, most preferably 28 to 41 wt%, based on total weight of the suspension. Use of such a suspension allows easy incorporation into the mixture of the fat. It was found that simple high shear mixing of the fat into the casein-containing suspension (in step (iii)C) suffices to arrive at a pre cheese that has an adequate consistency and stability to be processed to the final cheese product in accordance with the invention. This consistency can be described as a thick, viscous yet pumpable mass. When starting from a MPC or MCI powder, suitable protein suspensions are obtained by mixing appropriate amounts of protein powder and water (or a suitable aqueous salt solution) until the protein suspension is obtained, optionally including one or more

concentration steps as described below. When starting from the aqueous protein suspensions having a total solids content of 15 to 20 wt.%, suitable suspensions of the protein in water are suitably obtained by subjecting an aqueous casein source having a total protein content of 20 wt.% or less to one or more concentration steps. Such concentration steps could typically involve one or more evaporation steps, filtration steps or the addition of highly concentrated protein suspension or even protein-rich powder. A combination of two or more of these steps is also feasible.

The protein suspension is heated to a temperature above the melting temperature of the fat that is subsequently added whilst stirring or otherwise imparting shear to the mixture. The fat is preferably added in liquid form, so that it can be effectively mixed into the suspension to obtain a fat-in- water emulsion. However, it may also be added in solid form. In that case the fat will first be allowed to melt in the water before the melted fat is effectively mixed and a fat- in- water emulsion is obtained. Cooling of this emulsion then yields the pre cheese. Cooling may take place to a temperature below the melting temperature of the fat used, so that the fat particles solidify in the emulsion before

acidification and coagulation takes place. However, this not necessarily need to be the case. For example, when using milk fat fractions as the fat source, then the melting temperature of such fat fractions may be lower than the temperature to which the pre-cheese is cooled. The actual temperature to which the emulsion is cooled is a temperature at which the subsequent step of acidification and coagulation suitably takes place. It was found that a temperature in the range of from 10 to 50 °C, more preferably 20 to 40 °C, is a suitable target temperature of the pre-cheese. Further processing of the pre-cheese precursor also suitably takes place within this temperature range.

A major advantage of the cheese-making process according to the invention compared to traditional cheese-making processes is the fact the removal of whey to isolate the curd is not needed or anyhow is much less. Such traditional processes include removal of whey to isolate the curd and hence make the inclusion of water-soluble ingredients into the curd formation process less attractive, because such ingredients will also get (partially) lost upon whey removal. The process according to the invention does not lose whey so that the ingredients that enter the pre-cheese will essentially all end up in the final cheese product. Looked at from a different angle, this same aspect offers another major attraction of the process according to the invention, because in comparison with traditional cheese-making no limitations need to be reckoned with in view of the whey quality. In traditional cheese making whey is separated from the curd and commercialized, as such or after further processing. As a result, such whey- producing traditional cheese making has its limitations in terms of additive use because the additives are likely to also end up in the whey, thus potentially affecting the properties and the value of the whey. Since in the invention process no whey is produced, there is no need to reckon with whey quality when it comes to considering additives that are beneficial to the cheese to be made.

Hence, when compared to the traditional ways of cheese making, the invention process offers vastly increased flexibility in ingredient use.

A further advantage of the process is that, since no or a very limited amount of whey is removed, all caseinomacropeptide (CMP) which is released on hydrolysis of kappa-casein by the action of renneting enzymes, is retained in the cheese. In traditional manufacture cheese the CMP would typically end up in the whey stream. Since CMP is of less value than other whey proteins such as ct- lactalbumin and b-lactoglobulin, it is beneficial to have this protein retained in the cheese rather than having to remove it from any whey stream.

It has been stated above that the instant process does not lose whey or hardly loses any whey. It should be noted, however, that depending on the equipment set-up, some whey may separate off from the curd. This amount, however, will in general not exceed 200 grams per kg of curd, i.e. an amount which is negligible when compared to the traditional ways of cheese making, where values exceeding 7500 grams of whey per kg of curd are typically observed. Preferably this amount does not exceed 100 grams per kg of curd.

The pre-cheese comprises 15-36 wt.% of protein and 15-36 wt.% of fat selected from anhydrous milk fat, an anhydrous milk fat fraction, butter, butter oil, and mixtures of two or more of these. Preferred amounts are 20-30 wt.% of the protein and 20-30 wt.% of the fat. It is to be understood that these

percentages relate to the weight of the components themselves. For instance, when using butter, one introduces both water and fat, and in such a case it is the fat that is to be attributed to the fat percentage, not also the water.

As stated above, the casein for preparing the pre-cheese can

conveniently be sourced from micellar casein isolate (MCI). Milk protein concentrate (MPC) can also be used, but is less preferred due to its relatively high content of whey protein. Both MCI and MPC are commercially available materials As said above, other names for these materials are in use and are familiar to the skilled person.

In the context of the invention, the term“pre-cheese” refers to the mixture that is prepared by combining the sources of casein and fat and optional additives, except for the starter cultures and/or acidulants, and the coagulant such as rennet. Hence, the pre-cheese will contain casein, fat, water, small amounts of components such as whey protein, lactose salts, and optionally other components, such as flavor enhancing additives, starches, etc. Upon addition to this pre-cheese in step (b) of the present process of a starter culture and/or acidulant and the coagulant such as rennet, processing into the final cheese or cheese product takes place without the customary removal of whey following curd formation and prior to ripening.

The terms“Dutch-type” and“Swiss-type” cheese refer to cheeses which are well-known in the art. See for instance Fox et al., Fundamentals of Cheese Science, Aspen Publishers Inc, page 391 (2000).

Since not all food legislations in the world will allow a cheese product made from, in part, non-milk fat to be denoted“cheese”, the term“cheese product” is also used in this description and in the claims. The terms“Dutch type cheese” and Swiss type cheese” and“Dutch type cheese product” and Swiss type cheese product” are used herein interchangeably, and the term“cheese product” stands for“Dutch type or Swiss type cheese product.”

Processing the pre-cheese produced in step (b) of the process of the invention to the final cheese product can be realized in manners known in the art, with the exception, of course, that the removal of whey is (largely or completely) dispensed with. Reference is made to the aforementioned Fox et. al. disclosure for an overview of manners known in the art. For example, an acidifier like starter culture, acid, acidulant, for example GDL, and a coagulant, like rennet and chymosin, are included in the pre-cheese. Different starters and starter mixtures may be used. The most common starters include a mesophilic starter (lactococcal starter), typically starters by CSK, Chr. Hansen or DuPont; propionibacteria, typically Valio PJS, and a taste imparting adjunct (mesophilic and/or thermophilic adjunct starter), typically thermophilic Valio Lb 161

(shocked/non-shocked). For example, a mesophilic 0-starter, R-608 by Christian Hansen, is used as a starter. The starter and its amount depend on the cheese type and the conditions used. It is known that the amount of bulk starter is usually 0.5 to 2 wt.%, typically 0.7 to 0.8 wt.% (based on total weight of pre cheese). The amount of DVS starter (DVS/DVI) is usually 0.001 to 0.5 wt.%, typically 0.01 to 0.25 wt.% (based on total weight of pre-cheese). In addition to a bulk starter, the method of the invention may use, for example, LH-32, BS-10 and CR-312 by Christian Hansen as such or in different combinations and amounts depending on the cheese and cheese-like product to be made as additional starters to impart taste. Alternatively, taste imparting adjunct starters may be added substantially simultaneously with milk-based minerals.

After the curd formation the shaped curd can be brined and ripened in ways known in the art. An alternative to brining in a bath or dry salting after curd formation is that salting already takes place in the pre-cheese using salts like sodium chloride and/or potassium chloride. It is also possible both to add salt to the pre-cheese and to perform bath brining or dry salting after curd formation. Ripening can occur using standard techniques. Thus, foils can be employed that are air tight or partially air permeable. Natural ripening is the other way of developing taste and texture. These techniques are all well-established in the art.

The Dutch- or Swiss-type cheese or cheese product of the invention suitably has a phospholipid content of 0.3 g or less per 100 g fat.

The invention further relates to the use of a casein source containing, based on dry weight, 60 wt.% or more of casein, to prepare a Dutch or Swiss type cheese or cheese product. Preferably, the amount of said source is such that 50 wt.% or more of the protein is casein, more preferably 70 wt.% or more.

Brief description of the drawings

Figure 1 shows the gelation profile of cheese making according to the invention as given in Example 4.

Figure 2 shows the RPC-HPLC chromatograms of samples 1 and 2 made in Example 5. The solid line belongs to sample 1, the dashed line to sample 2. The following Examples are presented to illustrate the invention.

Examples

Example 1: Preparation of concentrated MCI suspension

The starting material was twenty liters of a suspension of micellar casein isolate (MCI) in water. The suspension contained ~17 wt.% dry matter (based on total weight of suspension) and the dry matter consisted of ~88 wt.% protein. More than 90 wt.% of this protein was casein. The pH of the suspension was 6.25. The suspension was evaporated using a rotary evaporator at a temperature of 60°C and at a pressure of 5.0 kPa (50 mbar). After evaporation the solids content of the suspension was 32 wt.%, and its viscosity was 0.275 Pa.s. measured at a shear rate of 794 s ¹ and a temperature of 50°C using a AR2000 rheometer (TA

Instruments USA). The pH of the evaporated suspension was 6.2.

Example 2: Preparation of pre-cheese

1000 grams of the suspension prepared in Example 1 were heated to 50°C. 310 grams of anhydrous milk fat (AMF) which had previously been heated to 50°C were added. During addition of the AMF, a rotor- stator high- shear mixer was inserted in the blend and was run at 3000 rpm for 7 minutes. Particle size analysis was conducted after 7 min of shearing by means of static light scattering using a Malvern Mastersizer 2000. The surface weighted mean diameter (D3,2) was determined to be 0.00158 mm. Microscopic analysis of the sample indicated a fat-in-water emulsion. This pre-cheese contained 20 wt.% of casein, 24 wt.% of AMF, 4.2 wt.% of solids not being casein and AMF, and the remainder water.

Example 3: Preparation of pre-cheese

1000 grams of the suspension prepared in Example 1 were heated to 50°C. 310 grams of sunflower oil which had previously been heated to 50°C were added. During addition of the sunflower oil, a rotor- stator high- shear mixer was inserted in the blend and was run at 3000 rpm for 6 minutes. Particle size analysis was conducted after 4 min of shearing by means of static light scattering using a Malvern Mastersizer 2000. The surface weighted mean diameter (D3,2) was determined to be 0.0021 mm. Microscopic analysis of the sample indicated a fat- in-water emulsion. This pre-cheese contained 20 wt.% of casein, 24 wt.% of sunflower oil, 4.2 wt.% of solids not being casein and AMF, and the remainder water.

Example 4: Preparation of Dutch-type cheese

The pre-cheese prepared in Example 2 was processed into a Dutch-type cheese. In the pre-cheese the ratio of fat:solids-non-fat was about 1:1. An amount of 25 grams was placed in a container and held at 30°C. Rennet (Kalase, ex CSK Food Enrichment, The Netherlands) was added to the pre-cheese at a level of 0.5 ml/kg. The sample was subsequently incubated in a AR2000 rheometer (TA Instruments, USA) and the storage modulus (G’) was monitored as a function of incubation time. The results are shown in Figure 1 and indicate an initial lag period during which G’ remained more or less constant, followed by a steep increase in G’ with time from ~60 minutes onward. Such a profile is typical of rennet-induced gelation.

Example 5: Preparation of Dutch-type cheese

Another portion of the pre-cheese prepared in Example 2 was also processed into a Dutch type cheese. Rennet was added at a concentration 0.125 ml/kg. In addition, starter culture (Ceska-star C57; ex CSK, The Netherlands) was added at a level of 1 ml/kg. Samples were incubated for 5 hrs at 30°C and subsequently stored for 13 hrs at 7°C. The sample was subsequently analyzed by RP-HPLC using a method described by Visser et al. J Chromatogr. 548(1-2), pp. 361-370 (1991) The chromatogram is shown in Figure 2 as sample 1. For comparison a sample of raw skim milk was also analyzed by RP-HPLC using the same method and the chromatogram is included in Figure 2 as sample 2. From the

chromatograms shown in Figure 2 it is clear that virtually no residual kappa- casein in present in sample 1, but that para-kappa-casein is present. As expected, sample 2 contains kappa casein and no para kappa casein. These differences are due to the fact that the kappa casein in sample 1 has been hydrolyzed by the enzymes in the rennet and converted into para kappa casein.

Example 6: Preparation of Dutch-type cheese

Yet another portion of the pre-cheese made in Example 2 was processed into a Dutch type cheese. 5000 grams of the pre-cheese were placed in a container Rennet and starter culture were added and the material was incubated for 5 hrs. at 30°C. Subsequently, the material was incubated for 14.5 hrs. at 7°C and brine- salted. The compositional properties of the cheese are listed in Table 1. The values in Table 1 can be considered typical for Dutch-type cheese after brining.

Table 1: Cheese composition

Taste and texture of the cheese were very similar to the taste and texture of a reference Dutch-type cheese.