Field of the invention

The invention relates to cheese in a package wherein the cheese is coated with an edible layer. The invention further relates to a process for ripening cheese, and to the use of alginate and a package for ripening a cheese.

Background of the invention

Ripening is an essential aspect in the production of cheese. During ripening cheeses are susceptible to microbiological contamination, a problem that is addressed in various ways.

Cheeses may be coated using water-borne dispersions or emulsions of synthetic copolymers, for example comprising esters of monoglycerides of hydrogenated fatty esters as described in EP 141299. Well-known products comprise poly(vinyl acetate-co-di-n-butyl maleate), poly(vinyl acetate-co-ethylene) and the like. Coatings often are difficult to remove from a cheese and may therefore consist of multiple layers to facilitate removal, for example in WO 2008/110550 describing a two-layer coating comprising an inner coating that is a fat and an outer coating that is a polyvinyl acetate-based plastic foil.

Alternatively, the ripening process may be carried out by packaging cheese in a seal-tight film following the brining step. This approach, described in EP 1287744, is referred to as foil ripening and the films that are used normally do not allow water and/or oxygen to pass. Foil ripening is less labor intensive compared to coating but has only limited development of flavor in the cheese. This drawback can be overcome by using packaging materials that have specific water vapor transmission rates (WVTR) and/or oxygen transmission rates (OTR) as described in WO 2009/47332, describing e.g. a single or two or more thermoplastic layers, in particular a thermoplastic, monolithic film. Another drawback of foil ripening is that it does not allow for efficient introduction of coloring agents onto cheeses, which often is a key feature for discriminating between various cheeses.

A drawback of synthetic coatings is that they are non-edible and thus human intake must be avoided. This has been overcome by introduction of edible coating materials, for example based on alginate as described in EP 615691 . Unfortunately, in practice these edible coatings are not very successful since the edibility of the coating also attracts microbial contamination. Nevertheless, there remains a need for edible coating of cheeses. For example, because the coating can mechanically protect the cheese surface, or because the coating can be used to bring characterizing markings and colors to the cheese for the retailer and consumer to discriminate one type of cheese from the other.

Coating and packaging of cheeses may be combined. For example, preservation of cheese using an edible food gel and a package is described in US 4,911 ,935. However, rather than preventing microbial contamination this technology is developed with a different objective, namely to bring about growth of external flora on the coating layer of the cheese, by bringing surface ferments on the coating layer. The objective of US 4,911 ,935 is reached by providing a package with very high oxygen permeability.

Hence, there remains a need for the coating and packaging of cheese such that microbial contamination is avoided and additional requirements are met, such as efficient separation of the packaging layer from the coating layer, i.e. such that the coating retains good tackiness and/or there is minimal migration of coloring agents, if present, from coating to package.

Detailed description of the invention

The object of the present invention is to provide a cheese with an edible coating that may be ripened and/or preserved without being susceptible to microbial contamination.

In the context of the invention, the term “alginate” refers to alginic acid and derivatives of alginic acid. Derivatives of alginic acid include salts which include metal salts. Examples are calcium alginate, magnesium alginate, potassium alginate, sodium alginate and the like. Alginic acid (also called algin) is a linear copolymer with homopolymeric blocks of (1-4)-linked b-D- mannuronate and its C-5 epimer a-L-guluronate, respectively, covalently linked together in different sequences or blocks.

The term "bag" refers to a packaging container having an open top, side edges, and a bottom edge. The term "bag" also encompasses lay-flat bags, pouches, casings (seamless casings and back-seamed casings, including lap-sealed casings, fin-sealed casings, and butt-sealed back-seamed casings having back-seaming tape thereon). Casing configurations are known to the skilled person and are, for example, disclosed in US 6,764,729. Likewise, bag configurations, including L-seal bags, back-seamed bags, and U-seal bags (also referred to as pouches), are known from i.e. US 6,790,468.

The term "biodegradable" refers to films, polymers or products that have the ability to break down, safely and relatively quickly, by biological means, into the raw materials of nature and disappear into the environment. These products can be solids biodegrading into the soil (which we also refer to as compostable), or liquids biodegrading into water. Biodegradable plastic is intended to break up when exposed to microorganisms.

The term "film" is inclusive of plastic web, regardless of whether it is film or sheet or tubing. The term "package" is inclusive of packages made from containers or tubes, by placing a product in the article and sealing the article so that the product is substantially surrounded by the heat-shrinkable film from which the packaging container is made.

The term “tackiness” refers to the extent to which coating remains firm and visually unchanged and adhered to the cheese after storage in a package.

In a first aspect, the invention provides cheese in a package wherein said cheese is coated with an edible layer and said package has a water vapor transmission rate of at least 10 g/m ² .24 h measured at 10°C and 85% relative humidity according to ASTM E96B cup test.

Packaging the coated cheese results in achieving the object of the invention, namely to provide a cheese with an edible coating that may be ripened and/or preserved without being susceptible to microbial contamination. Using the packaging of the invention, ripening conditions close to those of foil-free cheeses are obtained while at the same time it was found that neither the coating material sticks to the packaging material, nor did any coloring agents migrate from coating to packaging. In comparative studies with polyvinyl acetate packaging, sticking of coating material to the package upon removal of the package was observed while also certain coloring agents, notably anatto, migrated from coating to package.

In an embodiment, the edible layer comprises natural ingredients based on polysaccharides, proteins and lipids, that may be extracted from plants, foods and animal tissues. These ingredients offer alternative packaging options that minimize environmental pollution at a relatively low cost. Proteins and polysaccharides have good film-forming abilities, although their barrier and mechanical properties are often limited, a problem that is solved in the instant invention. Examples of suitable polysaccharides, proteins and lipids that may be used in the context of the present invention are, but are not limited to, alginate, carrageenan, casein, gelatin, gellan (high acyl and low acyl), pectin, whey protein isolate, xanthan gum, and the like. These compounds may also be applied in mixtures in order to profit from individual beneficial properties. Use of alginate as ingredient for an edible coating has the additional advantage that application is simple by immersion in a liquid alginate solution which forms a coating upon contact with ions like calcium. The latter are (or can be made) available in regular cheese brining baths.

In an embodiment, the coating layer comprises additional components. For example, coloring agents may be added. Coloring agents are used to visually differentiate one brand or type of cheese from the other but can also function to alter the influence of light on the cheese. Advantageously, the edible coatings of the instant invention are highly suitable for adding coloring agents as coloring results in a homogeneous color. In contrast, EP 513922 describes an edible oil in water emulsion based on fats and emulsifiers wherein microbial protection is realized by the addition of an antifungal agent such as natamycin. These edible oil in water emulsions are however not suited for application of color to the surface of a cheese because coloration is non- homogeneous and more often than not results in smears that are not acceptable for retailers or consumers. An additional advantage of the coatings of the present invention is that coloring components do not migrate from the coating.

It has been established that compounds comprising both hydrophobic and hydrophilic groups can further improve tackiness of the coating of the present invention. For example, hydroxylated cellulose derivates, such as hydroxypropyl cellulose, are successful in this respect. Suitable additional components can also comprise antifungal and/or antimicrobial compounds. Suitable examples or non-synthetic products, examples of which are natamycin and/or nisin. Such compounds may be contained in the coating or applied on the coating of the present invention.

In an embodiment, suitable configurations of a package may be a film (which can be used to wrap around cheese), a bag or a pouch (in which the cheese can be placed). Advantageously, the package of the invention may be heat sealable.

In an embodiment, the package is biodegradable, for example as described in WO 2018/185235, and may consist of at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99% or 100% by weight of biodegradable polymers. Biodegradable polymers may be polysaccharides, (co)polyesters and their blends. Examples of suitable polysaccharides are starches, preferably potato starches and their derivatives. Examples of suitable biodegradable polyesters are polycaprolactone, polyhydroxy butyrate, polylactic acid esters or co-polyesters of 1 ,4-butanediol, adipic acid and terephthalic acid such as described in WO 96/15173. Further suitable biodegradable polymers are polyester amides, as for example described in WO 96/21692.

In an embodiment, the package includes a film comprising at least two layers referred to as A and B. For example, the package may be a film comprising three layers that may be A/B/A. In case of three-layer films, layer(s) A may be from biodegradable polymers such as Ecoflex, polycaprolactone, Ecovio (BASF), MaterBi (Novamont), and layer B comprises starch. The biodegradable polymer of layer(s) A may be a heat sealable biodegradable polymer.

In an embodiment, the package comprises, for example as described in WO 2009/047332, a thermoplastic layer, in particular a thermoplastic, monolithic film.

In one embodiment, the package comprises a single thermoplastic layer.

In another embodiment, the package comprises two or more thermoplastic layers of different or the same composition.

In all these embodiments, the surface of the layer(s) can be printed, for example for branding purposes, as known in the art. In case the package comprises at least two thermoplastic layers, printing can be positioned between two thermoplastic layers. Multilayer films can be obtained by methods known in the art such as co-extrusion or lamination. In the case of printing the outer layer in reverse, the multilayer structure is usually obtained by a laminating process.

Each thermoplastic layer can be a blend of several thermoplastic polymers. The thermoplastic polymer used for the thermoplastic film(s) is preferably a polyamide, a polyester, a polyether, the copolymers thereof or a mixture of at least two of these thermoplastic polymers. Preferred copolymers are block copolymers. More preferably, the thermoplastic polymer used for the thermoplastic film is polyamide, polyether ester, polyether amide or mixtures thereof. Examples of suitable polyamides are aliphatic polyamides, that may eventually be branched polyamides, such as PA6, PA46, PA66, PA6/66, PA11 , PA12, semi aromatic polyamides as MXD6, PA6I/6T, PA66/6T, fully aromatic polyamides and copolymers and blends of the listed polyamides. Compositions comprising polyamide may have a high amide content, such as for example PA6 in contrast to for example PA11 or PA12, since these polyamides as such have higher water vapor transmission rates than PA11 or PA12. Examples of suitable polyesters are polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene naphtanoate, polybutylene naphtanoate. A polyether ester respectively a polyether amide block copolymer is understood to be a copolymer containing soft blocks of a polyether and hard polyester respectively polyamide blocks. The polyether blocks are preferably those derived from base- or acid-catalyzed ring-opening polymerization of cyclic ethers such as epoxides, oxetanes, oxolanes, and the like. Mixtures of different types of polyethers can be used. Preferred polyethers are polyether polyols. Examples of polyether polyols include, but are not limited to, polyoxypropylene polyols, polyoxyethylene polyols, ethylene oxide-propylene oxide copolymers, polytetramethylene ether glycols, oxetane polyols, and copolymers of tetrahydrofuran and epoxides. Typically, these polyols with have average hydroxyl functionalities from about 2 to about 8. Preferred aliphatic polyether are a poly(alkylene oxide) derived from an alkylene oxide of 2-6 C-atoms, preferably 2-4 C-atoms, or combinations thereof. Examples include polyethylene oxide), poly(tetramethylene oxide), polypropylene oxide) and ethylene oxide-terminated polypropylene oxide). Suitable polyester respectively polyamide blocks in the polyether ester respectively polyether amide block copolymers are those defined above for the polyester respectively the polyamide. The hard polyester block is preferably built up from ethylene terephthalate or propylene terephthalate repeating units, and in particular from butylene terephthalate units. Preferred polyester blocks are PBT blocks. Preferred polyamide blocks are aliphatic polyamide blocks, preferably PA6, PA66 or PA12.

Examples and preparation of block co-polyesters are for example described in Handbook of Thermoplastics, ed. O. Olabishi, Chapter 17, Marcel Dekker Inc., New York 1997, ISBN 0-8247- 9797-3, in Thermoplastic Elastomers, 2nd Ed, Chapter 8, Carl Hanser Verlag (1996), ISBN 1- 56990-205-4, in Encyclopedia of Polymer Science and Engineering, Vol. 12, Wiley & Sons, New York (1988), ISBN 0- 471-80944, p.75-117, and the references cited therein.

The polyether ester and the polyether amide preferably has a polyether content of at least 30 wt.%. The amount of polyether ester and/or polyether amide in the thermoplastic film is preferably such that the ether content is at least 1 wt.%, more preferably at least 2 wt.% and even more preferably at least 4 wt.% (relative to the total amount of thermoplastic polymers in the thermoplastic film). The amount of polyether ester and/or polyether amide in the thermoplastic film is preferably such that the ether content is at most 70 wt.% (relative to the total amount of thermoplastic polymers in the thermoplastic film). Even more preferably, the thermoplastic polymers used in the thermoplastic film consist essentially of polyamide and polyether amide and/or polyether ester. It has surprisingly been found that a package comprising such a thermoplastic film can advantageously be applied for foil-ripening of cheese as such packaging allows to increase the ripening, but not at the expense of the flavor development, the consistency and the mould and/or yeast growth. More preferably, the thermoplastic polymers used in the thermoplastic film consist essentially of 70 to 90 wt.% of polyamide and 10 to 30 wt.% polyether ester (relative to the total amount of thermoplastic polymers in the thermoplastic film). The polyether ester preferably has a polyether content of at least 30 wt.%.

As outlined above, US 4,911 ,935 discloses a package with very high oxygen permeability. In our hands this feature proved to be detrimental for the production of cheeses where microbiological surface contamination is to be avoided. This applies to various cheeses such as semi-hard cheeses or rind cheeses such as for instance Cascaval, Cheddar, Edam, Emmental, Maasdam, Manchego, Gouda, Gruyere, Pecorino, Raclette, Rigatino, Taleggio, Tilsit, and Tomme Noire, and the like.

Thus, in an embodiment, the package has an oxygen transmission rate of at most 500 cm ³ /m ² .24 h.atm measured at 10°C and 85% relative humidity according to ASTM D3985. Preferably the oxygen transmission rate is at most 100 cm ³ /m ² .24 h.atm. More preferably, the oxygen transmission rate is at most 40 cm ³ /m ² .24 h.atm at 10°C and 85% relative humidity. Suitable ranges of oxygen transmission rate at 10°C and 85% relative humidity are from 1 cm ³ /m ² .24 h.atm to 100 cm ³ /m ² .24 h.atm, or from 2 cm ³ /m ² .24 h.atm to 40 cm ³ /m ² .24 h.atm, or from 3 cm ³ /m ² .24 h.atm to 35 cm ³ /m ² .24 h.atm. As outlined above, low oxygen transmission rates have the advantage that microbial contamination forms less easily, or not at all, on the surface of the (coated) cheese.

In an embodiment, the package has a water vapor transmission rate of at least 10 g/m ² .24 h measured at 10°C and 85% relative humidity according to ASTM E96B cup test. Advantageously, water vapor transmission through the package allows for the ripening process of the cheese to proceed to a large extend comparable to natural ripening of coated cheeses and results in favorable flavor. The water vapor transmission rate may, for example, be from 100 to 1000 g/m ² .24 h or from 500 to 900 g/m ² .24 h measured at 10°C and 85% relative humidity according to ASTM E96B cup test. Lower water vapor transmission rates, for example lower than 2 g/m ² .24 h as described in Del Nobile M.A. et al. (Carbohydrate Polymers 78 (2009) 151-156) are not suited for acceptable flavor development.

In an embodiment, the above water vapor transmission rate and oxygen transmission rate are combined to provide for ideal methods for ripening or preserving cheese, including the coated cheese of the invention. In an embodiment, the package has, at 10°C and 85% relative humidity, a water vapor transmission rate of at least 10 g/m ² .24 h and an oxygen transmission rate of at most 500 cm ³ /m ² .24 h.atm. In another embodiment, the package has a water vapor transmission rate of at least 10 g/m ² .24 h and an oxygen transmission rate of from 2 cm ³ /m ² .24 h.atm to 40 cm ³ /m ² .24 h.atm.

In an embodiment, the outer surface of the package may be printed and/or may include other packaging articles such as parchments or paper articles, traditionally used in cheese packaging, which are kept enclosed in the package.

It was found that the package of the present invention provides for optimal conditions for ripening the edible coated cheeses of the invention without the occurrence of microbial contamination that is normally associated with edible coatings. Further, it was found that tackiness of edible coatings in the package of the invention is superior over synthetic coatings such as the commonly used coatings based on vinyl acetate and maleic acid dibutyl ester copolymer, and tackiness remains good after prolonged periods of time.

In an embodiment no surface ferments are present on the coating edible layer of the cheese. Surface ferments for growing external surface flora in prior art documents such as US 4,911 ,935 are chosen from PeniciIHum species and are usually placed on the outer surface of the coating layer.

In a second aspect, the invention provides a process for ripening and/or preserving a cheese comprising the steps of:

(i) contacting a cheese with an edible layer;

(ii) introducing the coated cheese obtained in step (i) into a package containing an opening for receiving cheese;

(iii) closing the package.

In an embodiment, the cheese is contacted with a bivalent metal salt prior to or during step (i) and/or in between steps (i) and (ii). Bivalent metal salts such as calcium (but also magnesium and the like) were found to promote the formation of the certain coating layers, for example in case of alginate, carrageenan, gellan (high acyl and low acyl), and pectin. Calcium is amongst the preferred bivalent metal salts as it is relatively inexpensive and helps to form rigid structures.

In an embodiment, the method only includes cheese ripening, and in another embodiment, the method only includes cheese preserving.

In an embodiment, the method includes cheese ripening followed by preserving. Conditions for ripening and/or preservation may differ and typically range from a relative humidity of from 20 to 95% and temperatures of from 1 to 25°C.

Packaged cheeses may be stored at temperatures of from 10 to 20°C and at relative humidity of from 75 to 95%, for example in a maturation room or cell until, for example, a typical percentage of dry matter, taste, and/or color is reached.

In an embodiment, at least one brining pre-treatment of the cheese is performed before the method of the second aspect of the invention. The brining step may be performed as known in the art. Preferably a calcium salt is added or present during brining. This has the advantage that no additional crosslinking step is required which facilitates the coating and packaging procedure. For example, in the field of fresh dairy products, Del Nobile M.A. et al. (Carbohydrate Polymers 78 (2009) 151-156) describes a process for the production of fior di latte. In this process, the dairy product is dipped into sodium alginate solution and, prior to packaging in a foil with a very low water vapor transmission rate, is immersed in a calcium chloride solution to crosslink the polymeric matrix. In the instant invention the latter step is not required and hence in an embodiment the process of the second aspect is carried out without immersing the coated cheese obtained in step (i) in a calcium chloride solution. In the method of ripening of the present invention, at least a part of the ripening is performed while the cheese is present in the package.

In an embodiment, the package may be closed by clipping or sealing, for example by heat sealing. Preferably, the package tightly covers the surface of the cheese so as to avoid air remaining between cheese and package. Remaining air may lead to unwanted mold formation and/or non-homogeneous cheese ripening. Accordingly, the package may be vacuumed and, optionally, heat shrunk prior to closing, as commonly known in the art of packaging. Generally, the package is vacuumed at pressures comprised between 0.5 and 1000 mbar, preferably for hard to semi-hard cheese from 5 to 25 mbar and for sensitive cheese from 600 to 800 mbar. Heat-shrinking may be carried out by submersion in hot water baths, preferably at temperatures not higher than 90°C for no more than 5 to 10 sec. Alternatively, hot air shrinking may be applied, for instance by hot air heating at 140-160°C for no more than 5 to 10 sec. In a variant of the present method, the package is vacuumed and shrunk.

In an embodiment, the packaging container is a pre-made bag whereby the method comprises introducing cheese to be ripened into a bag or pouch and closing the bag, for example by hermetically sealing the opening for receiving the cheese to be ripened. The pre-made bag may be produced from flat film and contain at least one seal or alternatively, the bag may be produced from a tubular film resulting in a seamless tubular casing.

In another embodiment of the method of the invention, the cheese is packaged according to a form-fill-seal process, as known in the art, with a package or film as described above.

In an embodiment, the time allowed for ripening may be in the range of about 20 days or longer, and in general equal to or less than about 2 years, preferably equal to or less than about 1 year, such as for instance of about 3 months or less, depending on the cheese. For hard or semi- hard cheese, the ripening may be performed at temperatures such as for instance from 2 to 18°C, or from 4 to 15°C or from 10 to 14°C and at a relative humidity of 75-85%. Examples of cheeses to be coated and packaged according to the present invention are hard or semi-hard cheeses or rind cheeses such as for instance a Cascaval, Cheddar, Edam, Emmental, Maasdam, Manchego, Gouda, Gruyere, Pecorino, Raclette, Rigatino, Taleggio, Tilsit, and Tomme Noire.

In an embodiment, the present invention may further comprise adding an antimicrobial compound such as for instance natamycin and/or nisin. Such compound may be added to the solution comprising an alginate used in step (i) but may also be applied in between steps (i) and (ii) to the surface of the coated cheese.

In an embodiment, following step (i) no surface ferments are applied to the coated cheese. Preferably no surface ferments from PeniciIHum species are applied to the outer surface of the coating layer.

Advantageously, the method of the invention results in good consistency, flavor and taste of cheese and prevents undesired fermentations and mold growth. Also, the method of coating and packaging of the present invention results in maintenance of the shape of the cheese.

In conclusion, the method of the present invention results in cheeses that are coated with an edible layer which have undergone ripening closely resembling natural ripening and which do not suffer from microbial contamination in or on the edible coating during the ripening process. Advantageously, packaging materials can be removed without unwanted sticking of the coating to the packaging material and added components, such as coloring agents, do not migrate to cheese or packaging material.

In a third aspect, the invention provides use of an edible coating and a package for ripening and/or preserving a cheese. Preferably the edible coating comprises an alginate.

In an embodiment, the package has an oxygen transmission rates and/or water vapor transmission rate as outlined in the first aspect of the invention.

Also, the invention provides a ripened cheese comprising an edible coating obtainable according to the method of the second aspect.

In an embodiment, the coating comprises alginate. Advantageously, the cheese comprises a coating that is both edible and does not suffer from microbial contamination.

EXAMPLES

Materials Pack-Age (WO 2009/47332) was obtained from DSM in the Netherlands and is a moisture permeable breathable packaging membrane enveloping cheeses.

DelvoCoat 13014 was obtained from DSM in the Netherlands and is a vinyl acetate and maleic acid dibutyl ester copolymer dispersion. Example 1

Coating and packaging of small (approx. 20 g) cheeses

Cheeses used for coating and packaging were Mini Babybel cheeses from Le Group Bel, obtained from local retailers. Before use in the below experiments the Mini Babybel cheeses were taken out of their cellophane package and the non-edible red wax-like coating was removed. Subsequently, the cheeses were placed in a brine bath (containing 0.5 wt.% CaCL and 20 wt.% NaCI) for 60 minutes and dried for 15-20 minutes at ambient temperatures.

Alginate coating compositions were prepared according to the below Table. Reference cheeses were coated with DelvoCoat 13014. Table Alginate-comprising coating compositions (amounts are further specified in individual experiments)

Mini Babybel cheeses were dipped in the coating composition and subsequently dried at 22±1°C and a relative humidity of 40-60% for 4-6 h until dry coating according to visual inspection was obtained. The dried coated cheeses were sealed and vacuumed in Pack-Age and stored in a cheese ripening room (T = 12-13°C, relative humidity of 83-88%). The cheeses were monitored in time and the tackiness and migration of color from coating to cheese was evaluated after 17 days, 35 days, and 63 days. Tackiness refers to the extent to which the coating remains firm and visually unchanged after storage in Pack-Age as a result of which the Pack-Age can be removed from the coated cheese without any or all of the coating sticking to the Pack-Age. This parameter was established visually after opening of the Pack-Age and was scored from bad (-) to very good (++) with in-between values of +/- and +. Also, migration of color from coating to package was established visually and was scored from very bad (- -; extensive coloration of package observed) to very good (++; no coloration of package observed).

Cheese coating with anatto

Table Cheeses coated according to the above composition in which the coloring agent was anatto, or coated with DelvoCoat 13014; HPC = hydroxypropyl cellulose

Cheese coating with oxide de fer noir (B495)

Table Cheeses coated according to the above composition in which the coloring agent was oxide de fer noir (B495); HPC = hydroxypropyl cellulose; PG = propylene glycol.

Example 2

Coating and packaging of 1 kg cheeses

Gouda-type cheeses of 1 kg were brined, alginate-coated and packaged according to the above procedure. Tackiness and migration of color from coating to package was monitored with the essentially the same results as in Example 1 demonstrating that the combination of the invention outperformed the combination wherein DelvoCoat 13014 was use as coating material in terms of tackiness and color migration.