Coating for foods

Office for the

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® 1023085 (2?) Patent application: 1023085 © Filed: 02.04.2003 © lnt.CI.⁷

A23C19 / 16, A23P1 / 08

<td>@ Signed up:</td><td>® Patent holder (s):</td>

<td>05.10.2004 IE</td><td>Friesland Brands BV in Leeuwarden.</td>

<td>© Date:</td><td>(72) Inventors):</td>

<td> 05.10.2004</td><td>Everhardus Jacobus Franciscus van Aram at</td>

<td></td><td>Franeker</td>

<td>(45) Issued:</td><td>Sabine Fischer in Mierio</td>

<td>01.12.2004 IE 2004/12</td><td>Tjeerd Jongsma in Bennekom</td>

<td></td><td>® Authorized representative:</td>

<td></td><td>Mr. Ir. AW Prins et al. At 2508 DH The Hague.</td>

@ Coating for food.

The invention relates to a method of coating a foodstuff by applying an aqueous film-forming composition thereon. The invention further relates to an emulsion which can be used for that method and the method for preparing it. Finally, the invention relates to a foodstuff with the coating applied to it.

NL C1023085

The contents of this patent correspond to the original filed description with claim (s) and any drawings.

Title: Food coating

The invention relates to a coating for foodstuffs such as fruit and fruit products, meat products and in particular sausage, and preferably for cheese, as well as methods for preparing and applying that coating. The invention further relates to a foodstuff and in particular cheese provided with such a coating.

When preparing many foods, the food is at some point coated. Coatings on foodstuffs have the object, among other things, of protecting the foodstuffs against external influences, such as fluctuations in temperature and humidity 10, and in particular against damage and microbial influences. The quality of a food, for example taste, smell, freshness, mouthfeel,₄cuttability and shelf life are generally positively influenced by a coating, a coating or other barrier to the environment.

Furthermore, a coating on food can play a role in controlling and influencing the ripening process. This role places particular demands on the gas barrier and moisture barrier properties of the coating. For example, maturing cheese of the hard and semi-hard type requires a certain degree of exchange of gases between the (young) cheese and the environment. At the same time, part of the moisture, mainly water, present in the cheese emerges.

It is desirable to maintain a higher moisture content in cheese for a number of reasons.

On the one hand, a higher moisture content in cheese gives advantages in the ripening process; microbiological maturation processes in which enzymes play an important role are better in an aqueous medium than in a somewhat drier environment. On the other hand, the exit of moisture, in particular water, has the effect of decreasing the amount of cheese prepared from a liter of milk. In addition, the exit of water means that noonor, for example, decreases the slicability of older cheeses: older cheeses become more granular and crumbly.

In the food industry, coatings have been proposed from many different materials, which may or may not have been pre-treated and post-treated. For example, casings and other intestines have traditionally been used to package meat products into sausages. The use of plastic films and gel-forming compositions as a coating is also well known.

In the cheese industry, coatings are usually based on materials consisting of one phase, such as paraffin or wax coatings, or from emulsions that are usually applied or applied in several layers, for example the so-called cheese plastics.

The present invention is particularly directed to, but not limited to, an emulsion-type coating for foodstuffs. Coatings based on, for example, combinations of dry materials, emulsions and single-phase systems, which are applied in a desired and suitable order, are within the scope of the invention.

Known emulsion coatings - which incidentally form the basis of the products according to the invention with the modification according to the invention, may for instance be based on polysaccharides (see for instance EP-A-0 615 691, which describes an alginate-based coating), proteins (see, for example, EP-A-0 593 123, which uses gluten, a water-insoluble protein and EP-A-0 594 258, which describes a caseinate-based coating), polyvinyl acetate or polyethylene. Such emulsions can be applied to foodstuffs by repeatedly applying a layer of aqueous emulsion thereon, which layer hardens by evaporation of water. Contacting foodstuffs with the emulsion can be done by immersing the food, spraying it, brushing it with a sponge or brush, etc.

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It is an object of the present invention to apply a (multilayer) material or combination of materials with desired properties to a foodstuff in a simple and efficient manner.

In particular, the invention aims at providing a food coating of which the gas and / or liquid barrier properties can be controlled. For example, a cheese coating can be provided, the gas diffusion properties of which are not adversely affected and the moisture loss is limited. On the other hand, the moisture and gas barrier properties can also be controlled to limit both.

It has now been found that by incorporating, for example by mixing, dispersing or otherwise introducing particles of a plate-shaped material, and in particular such water-swellable particles, such as clay types in a basic coating for foodstuffs, advantages are obtained. In particular, it has been found that foods, such as cheese, which are coated with a coating incorporating water-swellable clay types or other particles of a plate-shaped material, experience significant decreases in water loss compared to foods that have a corresponding coating that does not incorporate clay . For example, it has been found that 3 months after applying the cheese coating according to the invention to a cheese, the moisture loss of that cheese is at least 5%, and as a rule at least 10% less than with a cheese that has the same cheese coating without the clay contains.

In a first aspect, the invention relates to a method of coating a foodstuff, comprising applying an aqueous film-forming composition thereon and allowing this composition to dry and applying food-compatible water-swellable particles of a plate-shaped material, and especially such clay particles.

As an aqueous composition, an emulsion of film-forming material is used in which 0.5-25 wt.%, More preferably 0.5-15 wt.% And most preferably 1-7 wt.%, Based on the weight of the film-forming material, of the water-swellable particles is included.

In a second preferred embodiment, the plate-shaped material, and in particular the clay material, is added in a separate step. It is preferred to then apply the material particles as a dry powder to the foodstuff before or after the application of the aqueous composition and to remove any superfluous powder, for example by beating, blowing or vibrating off. After swelling of the dry particles, in particular the clay particles, for which an amount of water is optionally applied, a layer of film-forming material can then optionally be applied. Incidentally, the plate material, such as the clay particles, can also be applied in an aqueous dispersion separately from the film-forming material.

In a further aspect, the invention relates to an emulsion (or dispersion or colloidal solution) for use as an aqueous composition in the method according to the invention, comprising particles of a film-forming material in an aqueous medium and 0.5 - 25% by weight, based on the weight of the film-forming, food-compatible water-swellable particles of a plate-shaped material, in particular clay particles.

A further aspect of the invention relates to a method for preparing an emulsion for coating foodstuffs according to the invention, wherein the particles of plate-shaped material and in particular the clay particles are uniform in a conventional coating material for foodstuffs, comprising film-forming particles in water, are distributed in an amount of 0.5-25% by weight, based on the weight of the film-forming material.

The invention furthermore relates to the use of water-swellable particles of plate-shaped material and in particular clay particles in a • 4 ι Λ Λ Λ -.

food coating made of a film-forming material for the retention of moisture in the food. More in detail, this means that when the particles are present in a given coating, less moisture exits at least slower over time than when the same coating is used without clay particles. It is believed - without wishing to be limited to any theory - that the presence of plate-shaped particles considerably increases the path length that the moisture must travel in order to exit the coating. Incidentally, the coating according to the invention can also be formulated in such a way that gases and in particular oxygen are also hindered from entering or leaving the food, depending on the concentration of the plate-shaped material, and this coating is therefore also applicable in principle as a barrier layer for gases and in particular for oxygen.

In addition, the invention relates to a foodstuff and in particular a cheese, such as a cheese of the hard or semi-hard type available according to the method according to the invention.

The particles of a film-forming material used according to the invention are usually conventional materials for preparing a coating on foods such as cheese. The coating can be formed on the basis of synthetic polymers, as well as on the basis of natural polymers such as polysaccharides or proteins. Very suitable is the use of polyvinyl acetate particles which are conventionally used as a cheese coating, for example the product CESKA WL 250, which is commercially available from CSK Nederland.

Other suitable plastic materials include shellac, ethylene / vinyl acetate copolymer (EVA) (see e.g. EP-A-1151 671), acetic esters, monoglyceride fatty acids (see e.g. EP-A-0 679 337), polyhydroxyalkanoate (see e.g. US-A- 2002068810 and US-A5.958.480), polysaccharides (see for example EP-A 0 594 258 and EP-Ai η «

O 615 696), proteins (see, for example, WO 01/80658, EP-A-0 593 123, EP-A0 594 258) and polyethylene and acrylate emulsions. The said publications are included in the present specification to further describe the coating compositions.

Usual concentrations of these film-forming particles in the aqueous base are not particularly critical and can be, for example, between 1 and 80% by weight. However, in order to make the process practicable especially in view of the drying time, contents of 20-70% by weight and more preferably 30-60% by weight of film-forming material in the aqueous solution are preferred.

Incidentally, it is known from the prior art to add clay particles to plastic material, both as an (inert) filler as a component that modifies the properties of the plastic material. This usually concerns so-called nanocomposite materials.

For example, WO-A-Ol / 68762 discloses the addition of clay to a biodegradable thermoplastic material to which a plasticizer is further added. It is indicated that an increased moisture barrier is obtained, so that the biodegradable material, for example starch, remains dimensionally stable in water.

International patent application WO-A-01/04050 concerns a so-called nanocomposite coating and its preparation. Here, a layered material, for example a natural or synthetic clay, is added as a filler to a polymer. This is done using a modifying material because a priori inorganic materials and polymers do not mix well. This phenomenon is caused by the hydrophilic and hydrophobic character of the components, respectively. More specifically, a modifying agent containing two ionic groups is added, which groups are separated by at least 4 nonionic atoms. Partly because of this, specific requirements are imposed on the preparation of such a nanocomposite.

In WO-A-01/04216, the addition of a clay to a polymeric matrix is ​​also used to color the polymer. Due to the better (time and UV) stability of organic dyes, which are fixed on the surface of the clay particles, this provides a suitable alternative dye, which also has other desirable properties.

A good general example from the literature about the behavior of clay in an emulsion can be found in the article “B. zu Putlitz, K. Landfester, H. Fischer, M. Antonietti, Adv. Mater. 2001.13 No. 7,500-503 ”.

The coating as created in accordance with the invention contains particles of substantially food-compatible plate material. In more detail, plate-shaped means particles whose crystal structure consists of relatively easily splittable layers, both natural and synthetic materials, such as talc, graphite, mica and clay. Most preferred are clay particles, and the following description focuses on for example. It is explicitly stated that where clay particles are mentioned, many of the benefits are also obtained for other plate-shaped particles. The clay particles used in the emulsion according to the invention are natural or synthetic clay particles and preferably based on layered silicates, such as smectic type clay particles. Typical properties of clay are the layered structure and the ability to bind cations to the charged surface and exchange them with the medium in which the clay is located. The cationic exchange capacity (CEC, determined in milliequivalents [mol] per 100 grams of dry clay) is an important parameter of the clay in relation to the behavior of that clay in an aqueous medium. Clays suitable for nanocomposite materials have a layered structure and a cation exchange capacity of 30-250 milliequivalents per 100 grams, with a preference for a CEC of 50-150 meq / 100g. Suitable types of clay particles are described in the international patent applications discussed above and in particular in WO-A-99/07790. In preferred embodiments, the clay particles are bentonite, montmorillonite, saponite, hectorite, fluorhectorite, beidellite, nontronite, vermiculite, halloysite and / or stevensite type particles. These types may preferably be in the sodium form and preferably have an ion exchange capacity of 50-150 meq./100g clay. Given the use of the clay particles in a food coating material, the clays used are preferably not in a form that may raise food technology problems. In particular, (cat) ions present in the clays should not give any toxic effects. As a rule, the coating materials used will meet the legal requirements for food products.

According to the invention it is a great advantage to limit the loss of moisture during the preparation of foodstuffs, such as cheese, and in particular during the ripening and storage thereof, for instance in a cheese warehouse. This aspect of the invention will be described in detail below for cheese and the hard or semi-hard type, but is not limited to application to cheese. In particular, in a preferred embodiment, the invention provides a coating for cheese which on the one hand does not adversely affect the gas diffusion and on the other hand limits the moisture loss.

In particular, it has been found that in cheeses coated with a coating in which water-swellable clay types are dispersed, significant decreases in water loss occur, compared to cheeses having a similar coating, in which no clay is incorporated. More specifically, it has been found that during a period of 3 months after applying the coating according to the invention to the cheese, the moisture loss of that cheese is at least 5%, and as a rule at least 10% less than with a cheese which has the same coating without the clay; the same effect is of course also achieved over a longer period. In other words, the cheese η η η λ λ still loses a significant amount of moisture over time. However, the loss of moisture is measured fractionally limited at any time with the use of the coating. Such an effect is generic to the coating of the present invention. If desired, an aesthetic effect can also be achieved by adding specific clays, for example by imparting a specific color to the coating via the clay.

In a preferred embodiment, the emulsion according to the invention comprises 0.5-25 wt.%, And more preferably 1-7 wt.%, Based on the weight of the film-forming material of water-swellable particles of plate-shaped material. Very good results are achieved with an amount of about 5% by weight of clay particles, based on the total dry matter content.

The emulsion, or perhaps better, the suspension according to the invention requires, as essential ingredients in water, conventional film-forming material particles and food-compatible water-swellable clay particles or other plate-shaped particles. These particles may be introduced into the aqueous food coating in the form of a dry powder or may be subjected to a step first in which the particles are swelled in water, after which the particles are swollen in the aqueous food coating. are being brought. The aqueous coating for foodstuffs and the (clay) particles are then mixed with conventional means until no separate (clay) agglomerates can be distinguished, so that a homogeneous, uniform coating emulsion is obtained. This emulsion can be prepared by mixing the dry powder into the coating with stirring (200 - 20000 rpm) for 10 - 15 min. The clay, or other plate-shaped particles, can also first be placed in small amounts of water (50:50) to swell and then added to the coating emulsion. The clay can also be mixed into the coating in small quantities (master batch preparation). This coating master batch is then diluted to the desired concentration. Air bubbles can form in the mixture during stirring, which can be removed by venting under vacuum.

As mentioned, the emulsion or suspension for coating foodstuffs according to the invention in an aqueous medium comprises film-forming material particles and 0.5 to 25% by weight of clay particles. Depending on the way in which the clay is processed, it is preferable to choose a higher or lower concentration. For example, when the clay is added to foodstuffs in an emulsion coating composition, an amount of 0.5 to 15% by weight is suitable. When the usual method of applying a cheese coating from an emulsion is used, an amount of 0.5 to 8% by weight of clay particles is real. When the clay is applied as a paste, an amount of 15% by weight is a guideline, while when the clay is powdered on a wet emulsion of film-forming material, amounts up to 25% by weight are possible.

As a rule, for coating foodstuffs, such as cheese, comprising applying a layer of an emulsion according to the invention to a foodstuff and subsequently allowing that layer to dry, the steps of this method will be repeated several times in order to obtain a nice uniformly applied and obtain a sufficiently thick coating on the food layer. Incidentally, in the practical task, the food will first be treated with a part of the surface with the emulsion and, after the emulsion has dried, the food will be turned to treat the remaining part with the emulsion.

The foodstuffs, such as cheeses, which can be obtained according to the method according to the invention, have a lower moisture loss and thus a higher moisture content than corresponding foodstuffs of the same age, shape and weight, with no clay particles being present in the coating on foodstuffs. First of all, more moisture means better ripening and therefore a better taste. Furthermore, less essential flavors and fragrances are lost. The cheeses according to the invention are further smoother compared to reference cheeses not treated according to the invention and a higher yield is achieved. Furthermore, in particular older cheeses according to the invention are more cutable than the reference cheeses.

The invention therefore also relates to a cheese of the hard or semi-hard type, provided with a coating, which coating, based on the weight of the cheese plastic particles, comprises 0.5-25% by weight of clay particles.

Additives and processing aids common in this field may be added to the food coating composition of the invention. In particular, dyes and preservatives can be used.

The emulsion according to the invention can be applied by means of the usual procedures for applying coating to foodstuffs. For example, the emulsion can be applied with a sponge or brush, by dipping and by spraying.

When dry clay particles are applied in the form of a powder to the food, the moisture present in the food initially ensures the mutual adhesion of the dry clay to the adhesion to the food. Excess clay can then be removed. A standard coating can then be applied in the usual manner. These steps can be repeated as many times as necessary to obtain a good coating. The powdered clay 25 can equally well be applied to the still moist standard coating, which in this case has been applied first. The steps of applying clay powder and standard coating are interchangeable in order.

The invention will now be further elucidated by means of the following non-limiting examples. In these examples, a natural clay of the montmorillonite type has been used. It is a generally available sodium bentonite clay with an ion exchange capacity of 110 meq./100g (110 milliequivalents per 100 g clay).

Other experiments have been carried out with a synthetic clay. It concerns a Laponite RD clay, synthetic silicate with a layered structure - hectorite type, ion exchange capacity of 55 meq./100 g clay from Rockwood Additive Limited.

The weight percentages of clay particles are always based on the weight of the film-forming material - unless otherwise indicated.

Example 1

A mixing vessel was charged with 3 kg of a standard coating for foodstuffs such as cheese, (the polyvinyl acetate latex CESKA WL 250 from CSK (Netherlands)). Then, 90 g of the natural sodium bentonite clay described above were slowly added to the coating, while the mixture is stirred in the mixing vessel of a Hobart Planetary mixer. The whole mixture was then stirred at a low speed (300 500 rpm) for 15 minutes, resulting in a homogeneous mass. The appearance of a homogeneous mass was visually observed; there were no more clay nuggets. This clay-enriched coating for cheese was ready to be applied to cheeses.

Example 2:

g of the above-described natural sodium bentonite clay was mixed with 90 g of water in a Hobart Planetary mixer at a stirring speed of 200 rpm. The clay swelled. To this swollen clay mass, 3 kg of the standard food coating described in Example 1 was added with stirring in the Hobart mixer at 300-500 rpm. This greatly increased the viscosity of the mixture; a thick paste obtained ι λ r »AAO Γ. It was too thick to apply to a cheese. Therefore, 1000 ml of additional water was added to the mixture to simplify the application of the coating to the cheese.

Example 3:

A stainless steel cup was filled with an amount of standard cheese coating CESKA WL 250 from CSK. To this cheese coating agent with a solid content of about 40% by weight, an amount of the above-described natural sodium bentonite clay 10 was then added with stirring, so that a concentration of 5% by weight of clay with respect to the total solids content is obtained. The amount of clay was added slowly while the latex was stirred with an impeller disc at a stirring speed of about 5000 rpm. After the clay has been added, it is further dispersed by increasing the stirring speed to 10,000-12,000 rpm for about 15 minutes.

The resulting homogeneous dispersion is then deaerated in a vacuum dissolver with slow stirring (about 5000 rpm) with an impeller disc while applying a vacuum for 3 to 5 minutes.

The homogeneous, 5% by weight clay-containing cheese coating agent thus obtained was suitable for application to cheeses.

Example 4:

A stainless steel cup was filled with an amount of standard cheese coating agent, a latex based on polyvinyl acetate CESKA WL 250.

To this cheese coating agent with a solid content of about 40% by weight, an amount of the above-described natural sodium bentonite clay was added while stirring the cheese coating agent, so that a concentration of about 15% by weight of clay with respect to the total solids content is obtained. The amount of clay was added slowly while the latex was stirred with an impeller disc at a stirring speed of about 16000 rpm until a homogeneous paste was formed.

A second stainless steel cup was filled with an amount of standard cheese coating. An amount of paste was added to this latex to give a concentration of clay in the cheese coating agent of 1% by weight relative to the total solids content. The paste is mixed with the cheese coating agent by slowly stirring with an impeller disc, at a stirring speed of 3000-5000 rpm.

The resulting homogeneous dispersion was then vented in a vacuum dissolver by slow stirring (3000-5000 rpm) with an impeller disc applying vacuum for 3 to 5 minutes

The homogeneous cheese coating agent filled with 1% by weight of clay thus obtained was suitable for application.

Example 5:

A stainless steel beaker was filled with an amount of standard cheese coating agent, a latex based on polyvinyl acetate CESKA WL 250. To this cheese coating agent with a solid content of approximately 40% by weight, an amount of synthetic 20 Laponite RD clay was then added with stirring of the cheese coating agent. an ion exchange capacity of 55 meq./100 grams of clay was added to give a concentration of 5 wt.% Laponite RD with respect to the total solids content. The amount of Laponite RD was added slowly while the latex was stirred with an impeller disc, at a stirring speed of about 5000 rpm. After the clay was added, it was further dispersed by increasing the stirring speed to 10,000-12,000 rpm for about 15 minutes.

The resulting homogeneous dispersion was then deaerated in a vacuum dissolver by slow stirring (approx. 5000 rpm) with an impeller disc while applying vacuum for 3 to 5 minutes η oonoc

The homogeneous cheese coating agent filled with 5% by weight of Laponite RD now formed was suitable for application.

Example 6:

The coatings obtained in Examples 1 and 2 were applied in a traditional manner on 4 kg of brine-dry model Gouda cheeses using a sponge. After 24 hours, the applied layers were found to be sufficiently dry and the cheeses were turned to also provide the other side with a coating layer on the other side. The cheeses were always stored on wooden shelves in a cheese warehouse under otherwise usual ripening conditions and usual treatments such as periodic turning. In total, in 8 steps, 4 layers of coating were applied on each side for 4 weeks.

The cheeses prepared according to the above description were then compared with each other and covered with a cheese with the standard coating. By weighing before and after the coating treatment, the amount of coating material applied could be compared with that on cheeses treated with the standard coating on foodstuffs without addition.

For a period of 3 months (90 days), the cheeses were stored and treated in the usual manner. During this period, the weight of the cheeses was regularly determined in order to determine the moisture loss. At the end of the test period, depending on the amount of coating applied, all cheeses had a more or less smooth rind and no cheese showed any visible signs of mold development.

The cheeses according to the invention had lost significantly less water compared to standard cheeses on which the same coating was applied, but without the clay material. To this end, reference is made to figure 1, in which the curves indicated by N, A and B are the curves for the reference cheese, the cheeses treated with the material of example 1 and the cheeses treated with the material of example 2, respectively (always duplicate determinations ). The cheeses according to the invention lost up to about 20% by weight less moisture compared to the reference cheese in the said period.

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