PROCÉDÉ DE PRODUCTION D'UNE PORTION EMBALLÉE DE PRODUIT ALIMENTAIRE, ET PORTION OBTENUE PAR CE PROCÉDÉ

A method of producing a packed portion of food product, and portion obtained by this method

The present invention relates to a method of producing a sealed packaged portion of food product, and the packaged portion obtained by the implementation of this method.

Such packaged portion is generally of the type comprising a cup defining a food product receiving space and a cover lid of the food product and closing the bucket, the flaps of the bucket, thermally conductive, being folded on an outer face of the lid opposite to the receiving space and sealed to said outer face, the food product being contained within the receiving space and covered by the cover.

The invention applies more particularly to the production of waterproof portion packs of food measured cold, that is to say at a temperature below 50 ° C, such as, without limitation, fresh cheeses or obtained by a recombination method (eg cheese products described in WO 2006/030128 and WO 2008/151820) or by membrane techniques, put in the viscous or pasty liquid state, the cold pack cheese, yogurt derivatives or any other dairy product fresh with live cultures, bouillon cubes or butter.

Most commonly, food products assayed cold when they are packaged as individual portions are simply packaged in a flexible sheet of material folded around the product dose. Examples of food products packaged in this way are butter and fresh cheeses marketed for example under the brand Boursin ^®. This type of simple conditioning has the disadvantage of not being waterproof, generating a rapid drying of the product and thus a reduced shelf life.

An object of the invention is thus to obtain a waterproof packaging a food product portion dosed cold, so as to prevent the product from drying and contribute to a better preservation of the product in time and an improvement in the product quality. The product shelf life is increased and extended export possibilities.

Packaged portions methods for producing sealed food, allowing the sealed packaging of products to be metered in the cold, are known. These methods generally involve the following steps:

- provision of a cup defining an interior space for receiving the food product,

- Cold dosage of the food product in the bucket receiving space, - coating the food product by means of a cover arranged so that bucket flaps are folded back outwards of the bucket after the covering step, and

- heat sealing the flaps on an inner face of the cover facing toward the receiving space.

For the sealing step is used most often metal sealing jaws that the temperature is raised and come to pinch therebetween the flaps and the lid by activating a heat sealing lacquer which are coated flaps.

Such a process is known for example from EP 1072535 and EP 2 284 082. A disadvantage of this method is that it results in the formation of a flange at the periphery of the portion, making it unattractive and impractical portion . Another disadvantage of this method is that it requires large amounts of packaging, which is not environmentally friendly.

Are also known packaged portions methods for producing sealed food products that may be assayed hot, that is to say with a temperature typically greater than 65 ° C, such as processed cheese, which allow to obtain sealed portion packs having no peripheral flange. These methods generally involve the following steps:

- providing a metal cup defining an interior space for receiving the food product,

- hot-dosage of the food product in the bucket receiving space,

- coating the food product by means of a metal cover arranged so that bucket flaps extend outside the cover after the covering step,

- folding flaps on an outer face of the lid opposite to the receiving space, and

- heat sealing the flaps to the outer face.

In the sealing step, most often uses a metal sealing iron that is raised in temperature and which bears against the flaps and pressing them against the cover and activating a heat sealing lacquer which are coated with the flaps. For the exercise of this pressure and of this heating, it seals the flaps and the lid which are in contact under the iron and the portion is compacted, it being understood that this compaction gives the part its final shape. It would be desirable to use such a method with a food product to be dosed cold, so as to obtain a sealed packed portion of food product to be dosed to cold that does not comprise a peripheral flange.

However, the fact that the food product is dosed in hot packaging constitutes an essential characteristic of these known methods. Indeed, the heat generated by the food product after its dosage is used as a major heat input to bring the heat sealing varnish beyond its melting temperature and thus allow activation. This allows heat supply including sealing portions in a sufficiently short time to keep industrial production rates.

A problem thus arises to replace the hot metering step by a cold assay step. Indeed, by measuring the food product contained in the portion to a temperature below the melting temperature of heat sealing lacquer, the food product can not contribute to heating the varnish beyond its melting temperature; on the contrary even, the food absorbs much of the calories from the sealing iron. Thereby replacing the hot metering step of the method above by a cold assay step, the sealing time is significantly lengthened, and it becomes impossible to hold an industrial production rate. Another disadvantage observed is that the heating of the food product contained in the packaging, sealing induced iron deteriorates the organoleptic qualities of the food product.

A solution to the above problem is proposed in EP 2177 437. It involves heating the bucket induction at the time of sealing.

This solution is complex and expensive to implement. Moreover, it does not completely solve the global food problem and the risk of loss of the organoleptic qualities that results.

An object of the invention is thus to enable a simple and inexpensive sealing of a packed portion of food product wherein the food product must be dosed cold without forming a projecting collar outside the portion. Other objectives are to avoid heating the food product contained in the portion over the seal and allow the holding of an industrial production rate.

To this end, the invention relates to a method of producing a packed portion of food product, comprising the steps of:

- provision of a cup defining an interior space for receiving the food product, - cold assay at a temperature below 50 ° C, the food product in the bucket receiving space,

recovery of the food product by means of a thermally insulating cover arranged such that the flaps of the bucket, thermally conductive, extend outside the cover after the covering step,

- folding flaps on an outer face of the lid opposite to the receiving space, and

- heat sealing the flaps to the outer face.

The fact that the cover is thermally insulating greatly limits the escape of heat to the food product during sealing, which achieves the dual goal of reducing sealing time and avoid warming food.

According to particular embodiments of the invention, the method also has one or more of the following features, (s) singly or in any (s) combination (s) technically possible (s):

- the sealing step includes the following sub-steps:

o application of at least one hot sealing iron on the flaps, the flaps being interposed between said iron and sealing the lid, and o activation of at least one thermo-adhesive material provided at the interface between the flaps and the lid heat medium made to the thermoadhesive material by the or each sealing iron;

- the step of applying the or each sealing iron comprises the successive applications of two sealing shoes on the flaps;

- the flaps comprise an inner side facing the receiving space, an outer side facing away from the receiving space, and have a first coefficient of surface heat transfer between their inner and outer faces, the cover comprises a toward the receiving space facing inner side and has a second coefficient of surface heat transfer between its outer and inner faces, and the ratio of the first coefficient of heat transfer surface on the second surface heat transfer coefficient is greater than or equal to 400, in particular greater than or equal to 800;

- the first surface heat transfer coefficient is greater than or equal to 10 ^7, especially greater than or equal to 1, ⁷ 3.10;

- the second surface heat transfer coefficient is less than or equal to 2,5.10 ^4, in particular less than or equal to 1, ⁴ 7.10;

- the flaps have a thermal conductivity greater than or equal to 200 Wm ^{"1 .K" 1;}

- the cover has a thermal conductivity less than or equal to 0.5 Wm ^{"1 .K" 1;} - the flaps consist mainly, and preferably more than 70%, of metal, particularly aluminum;

- the lid is composed of a majority, preferably more than 90%, of plastic, in particular foamed plastic material;

- the plastics material is a polymer, e.g., foamed-oriented polypropylene;

- the cover includes a plastic layer and a metallization layer deposited on at least one side of the plastic layer, said metallization layer being interposed between the thermoadhesive material and the plastic layer.

The invention also relates to a packaged portion of food product obtained by a production process according to any one of the preceding claims.

"In the context of the present invention, the term" portion "an amount of food product in a packaging container whose weight is between 5 and 250g '.

In particular, the invention also relates to a packaged portion of the aforementioned type, wherein the lid is thermally insulating and the food product is a dairy curd based product costs, alone or in mixture, or cheese from a method of recombination.

Other features and advantages of the invention will become apparent from reading the following description, an example given solely and with reference to the accompanying drawings, wherein:

- Figure 1 is a perspective view of a packaged portion according to a first embodiment of the invention, during production, at a coating step of the food product contained in the portion,

- Figure 2 is a perspective view of the packaged portion of Figure 1, once completed,

- Figure 3 is a sectional view taken along the III-III plane of Figure 1, of part of a bucket of the packaged portion of Figure 1,

- Figure 4 is a sectional view taken along the plane IV-IV of Figure 1, a packaged lid portion of Figure 1,

- Figures 5 to 9 are sectional views, taken along the plane VV of Figure 2, of the packaged portion of Figure 1 during successive steps of a production process of said wrapped portion - Figure 10 is a perspective view of a packaged portion according to a second embodiment of the invention, during production, at a coating step of the food product contained in the portion,

- Figure 1 1 is a perspective view of the packaged portion of Figure 10, once completed,

- Figure 12 is a sectional view taken along the plane XII-XII of Figure 10, of a portion of a bucket of the packaged portion of Figure 10,

- Figure 13 is a sectional view taken along the plane XIII-XIII of Figure 10, a lid of the packaged portion of Figure 10, and

- Figures 14 to 18 are sectional views, taken along the plane XIV-XIV of

Figure 1 1 of the packaged portion of Figure 10 in successive stages of a production process of said wrapped portion. The packed portion 10, shown in Figures 1 and 2, is a packed portion of food product containing a food product 12. It comprises a cup 14 defining a space 16 for receiving the food product 12, and a product recovery of 18 lid food 12 and closing of the bucket 14.

The food product 12 is for example a dairy curd based product costs, alone or in mixture, or cheese from a recombination method.

The bucket 14 has a bottom 19, a peripheral lateral wall 20 projecting from the periphery of the base 19 substantially perpendicular thereto, and the flaps 22 extending from an upper edge 24 of the side wall 20 opposite to the lower edge 26 connecting the sidewall 20 to the bottom 19. the receiving space 16 is defined between the bottom 19 and the sidewall 20.

The bottom 19a, in the example shown, the general shape of triangle. Alternatively, the base 19 has any other shape, e.g., a discoid or rectangular shape.

Each flap 22 extends from the upper edge 24 of the side wall 20 to a free edge 28. The distance from the free edge 28 to the upper edge 24 is preferably less than the distance from the top edge 24 to bottom edge 26.

In this first embodiment, the bucket 14 comprises a single sheet 30, folded upon itself, forming the bottom 19, the side wall 20 and the flaps 22. An example of folding the sheet 30 to form the bucket 14 is for example in FR 2888571.

The sheet 30 is thermally conductive. In particular, the sheet 30 has a thermal conductivity greater than or equal to 200 Wm ^-1 .K ^-1. For this purpose, the sheet 30 is composed predominantly, and preferably more than 70%, of metal, particularly aluminum.

In particular, as visible in Figure 3, the sheet 30 has a multilayer structure comprising: a main layer 32 of metal, in particular aluminum, defining an interior face 40 of the sheet 30, facing the receiving space 16, and an external coating 34 deposited on one side of the core layer 32 opposed to the inner face 40 and defining an outer face 36 of the sheet 30 facing away from the receiving space 16 ..

The main layer 32 is more than 70% in thickness of the sheet 30. It preferably has a thickness of between 10 and 12 μηι.

The exterior coating 34 typically comprises a layer of non-heat-adhesive lacquer, for example a layer of nitrocellulose lacquer. The exterior coating 34 has a thickness of between 2 and 4 μηι.

The thickness of the sheet 30 as measured between its outer and inner faces 36 40, is less than 20 μηι, and in particular less than 15 μηι. The sheet 30 thus has a first coefficient of surface heat transfer, between its inner 40 and outer faces 36, greater than or equal to 10 ^7, especially greater than or equal to 1, ⁷ 3.10.

Note that, since the sheet 30 constitutes the flaps 22, the inner 40 and outer surfaces 36 also are inner and outer faces of said flaps 22.

The inner face 40 is covered with a lining 38 of the separate sheet 30. This liner 38 comprises a thermoadhesive layer 42, defining an inner face 44 of the coating 38 oriented toward the receiving space 16.

The thermoadhesive layer 42 is made of a thermoadhesive material suitable for forming a bond with a compatible material when heated to a temperature above a threshold temperature. Said thermoadhesive material is preferably a hot-melt adhesive material at low temperature, that is to say that said threshold temperature is lower than 75 ° C. The threshold temperature remains above 58 ° C, so as to avoid any interaction between the thermoadhesive layer 42 and the food product 12 to the normal temperature food product shelf 12. The threshold temperature is typically a melting temperature of the thermoadhesive material .

The thermoadhesive layer 42 comprises for example a vinyl layer.

Preferably, as shown, the liner 38 comprises, in addition to the thermoadhesive layer 42, a protective layer 46 interposed between the thermoadhesive layer 42 and the sheet 30. This protective layer 46 is adapted to protect the sheet 30 against corrosion .

The protective layer 46 comprises for example a vinyl layer.

Alternatively (not shown), the inner liner 38 is constituted by the single layer thermoadhesive 42, it then preferably being adapted to protect the sheet 30 against corrosion.

Examples of other materials which enter into the composition of the thermoadhesive layer 42 and / or the protective layer 46 are paint-like materials, including for example plasticized PVC type polymers or copolymers of PVC with the ethylene, vinyl laurate or vinyl acetate, or polymers based on olefins such as ethylene, butadiene, and copolymers thereof, or ester-based polymers such as PLA, acetate vinyl, vinyl esters of fatty acids, fatty alcohols, acrylic acid and fatty alcohols of methacrylic acid, or polymers based on terephthalic acid and ethylene glycol modified or not, and materials obtained by extrusion of a polymer, typically an ethylene-based polyolefin, butadiene and copolymers thereof, and / or a vinyl polymer to vinyl chloride-based, and / or vinyl esters of fatty acids, and / or fatty alcohols of acrylic acid, and / or alcohols fatty methacrylic acid, said extrusion being typically carried by the curtain technology raw material in the viscous liquid state, the curtain material technology in the form of an aqueous suspension or emulsion, by coating a suspension or emulsion polymer in water, for example by spraying or wiping a brush or a strip.

The total thickness of the liner 38 is preferably between 4 and

6 μηι.

Returning to Figures 1 and 2, the cup 14 also includes an element 48 for guiding tears in the sheet 20. This guide member 48 is typically formed by at least one guide strip attached to the inner face 40 of the sheet 30 and sealed thereto. An example of arrangement of said guide strip on the inner face 40 is given in FR 2888571.

The cover 18 is opposite the base 19 with respect to the receiving space 16, that is to say that the receiving space 16 is interposed between the bottom 18 and the cover 19.

The cover 18 is substantially flat.

The cover 18 is thermally insulating. In particular, the cover 18 has a thermal conductivity less than or equal to 0.5 Wm ^-1 .K ^-1. For this purpose, the cover 18 is composed of a majority, preferably more than 80% even more than 90%, of plastic, in particular foamed plastics material. Said plastics material is advantageously a polymer, e.g., oriented polypropylene (OPP).

In particular, as seen in Figure 4, the cover 18 has a multilayer structure comprising: a main layer 50 of plastic, in particular foamed plastics material, for example expanded OPP, and an outer coating 52.

The main layer 50 is more than 90%, preferably more than 99%, the thickness of cover 18. It has in particular a thickness of between 20 and 60 μηι, preferably between 30 and 40μηι.

The main layer 50 defines an inner face 54 of cover 18, facing the receiving space 16.

The outer coating 52 is deposited on one face of the core layer 50 opposed to the inner face 54. It defines an outer face 56 of the cover 18 facing away from the receiving space 16.

The outer coating 52 comprises a layer of metallization and is advantageously constituted by said metallization layer. This metallization layer is used to form a barrier to light and gas that protects the food product 12. It is preferably composed mainly of aluminum.

The outer coating 52 preferably has a thickness of several angstroms. To this end, the metallization layer is deposited by vacuum evaporation of the metal constituting said layer. Thus, the effect of the metallization layer on the thermal conductivity of the cover 18 is negligible.

The thickness of the cover 18, taken between its inner faces 54 and outer 56, is greater than 20 μηι, and in particular greater than 30 μηι. The cover 18 thus has a second coefficient of surface heat transfer, between its inner and outer faces 54 56, less than or equal to 2,5.10 ^4, in particular less than or equal to 1, 7.10 ^4.

The ratio of the first heat transfer coefficient on the second heat transfer coefficient is thus higher than or equal to 400 and in particular greater than or equal to 800. This large difference between the first and second heat transfer coefficients ensures that in case of applying a hot item onto the outer face 36 of the flaps 22, calories are quickly transferred from the hot element to the interface between the flaps 22 and the cover 18, but that these calories flee much slowly through the cover 18 to the food product 12.

The outer face 56 is coated with a thermoadhesive coating 58 separate from the cover 18. This thermoadhesive coating 58 is made of a thermoadhesive material suitable for forming a bond with a compatible material when heated to a temperature higher than a temperature threshold. Said thermoadhesive material is preferably a hot-melt adhesive material at low temperature, that is to say that said threshold temperature is lower than 75 ° C. The threshold temperature remains above 58 ° C, so as to avoid any interaction between the thermoadhesive coating 58 and the food product 12 to the normal temperature food product shelf 12. The threshold temperature is typically a melting temperature of the thermoadhesive material .

The adhesive materials of thermoadhesive coating 58 and the thermoadhesive layer 42 are compatible materials.

Returning to Figures 1 and 2, the flaps 22 are folded on the outer face 56 of the cover 18 and are sealed in a sealed manner to said outer face 56 through the thermoadhesive coating 58 and the thermoadhesive layer 42. The flaps 22 are in particular folded inwardly of the bucket 14 relative to the side wall 20.

A process for producing the packaged portion 10 will now be described with reference to Figures 5 to 9.

First, as shown in Figure 5, the sheet 30 is folded so as to form the cup 14. To this end, the sheet 30 is folded for example as described in FR 2,888,571.

Then, as shown in Figure 6, the food product 12 is determined to cold, that is to say at a temperature below 50 ° C, in the receiving space 16 of the cup 14. The food product 12 is in particular dosed at a temperature between 0 and 30 ° C, preferably between 0 and 20 ° C and more particularly between 5 and 15 ° C.

Then the food product 12 is covered by the cover 18. For this purpose, the cover 18 is inserted between the flaps 22, the inner face 54 being oriented toward the food product 12, and descended between the flaps 22 to be in contact with the food product 12, as shown in Figure 7. Thus, at the end of this covering step, the flaps 22 extend outside the cover 18, that is to say the cover 18 is interposed between the flaps 22 and the food product 12.

Recovery of the food product 12 by the lid 18 is followed by a step, shown in Figure 8, bending of the flaps 22 inwardly of the cup 14, on the outer face 56 of the cover 18.

Then, as shown in Figure 9, the flaps 22 are heat sealed under pressure to the outer face 56 of the lid 18. This sealing of the flaps 22 of the cover 18 comprises preferably, as shown, a step of pre- sealing and final sealing step.

The pre-sealing step includes applying a first hot sealing iron 60 on the flaps 22, the flaps 22 being interposed between said first iron 60 and the cover 18, the first iron sealing 60 pressing the flaps 22 against the cover 18. the final sealing step comprises applying a second hot sealing iron 62 on the flaps 22, the flaps 22 being interposed between said second iron 62 and the cover 18, the second sealing iron 62 pressing the flaps 22 against the cover 18. Said applications are successive applications succeed one another with preferably an interval of time less than 2 s.

Each of the sealing shoes 60, 62 comprises a hot metal member 64, that is to say at a temperature typically above 120 ° C, defining a contact face 65 with the flaps, said contact face 65 having substantially the shape of the contour of the lid 18. preferably, however, the metal member 64 is at a temperature lower than 140 ° C, so as to prevent its application against the flaps 22 will not damage the plastic of the lid 18.

In order to prevent the metal member 64 is in contact with the cover 18, which may damage the cover 18, a recess 66 is formed at the center of the metal member 64, the contact face 65 defining the periphery of said recess 66.

An insulating insert 68 is housed in said recess 66 and is flush with the contact face 65. This prevents the pressure exerted by the sealing shoes 60, 62 of the flaps 22 does not cause deformation of the sealed portion 10 at its periphery.

This insulating insert 68 is composed of a thermoplastic or thermoset material to high melting point, for example bakelite, a cotton canvas Bakelite, or polyetheretherketone.

Upon application of each iron sealing 60, 62 against the flaps 22, heat is transferred from the sealing iron 60, 62 to the thermoadhesive coating 58 and the thermoadhesive layer 42 through the flaps 22. This heat transfer is fast, since the flaps 22 are thermally conductive. The insulating cover 18 is, it prevents the heat transferred to the thermoadhesive coating 58 and the thermoadhesive layer 42 from leaking to the food product 12. The heat builds up at the interface between the flaps 22 and the cover 18, which causes a rapid rise of the surface temperature thermoadhesive 58 and thermoadhesive layer 42 to a temperature above the threshold temperature of the thermoadhesive material components. Said thermoadhesive materials are thus activated by the heat and form a bond between the flaps 22 and the lid 18. It is this bond that seals the flaps 22 to the lid 18.

Note that to use the successive application of two sealing irons 60, 62, rather than applying a single iron sealing, can significantly reduce the duration of application of each sealing iron 60, 62 to obtain a tight sealing of the portion 10. It is thus possible to raise the portion of the packaged production rate 10 until a rate identical to the rate of production of processed cheese portions metered hot.

The description of the packaged portion 10 given above is largely applicable to the packaged portion 100 shown in Figures 10 is January 1. For simplicity, the same reference signs have been so used to designate elements common to the wrapped portions 10 and 100, and the common features have been omitted from the description below.

The packed portion 100 differs mainly from the packed portion 10 in that the sheet 30 does not constitute the bottom 19 of the bucket. Unlike the packed portion 10, the bottom 19 comprises in fact here a base 102 sealed to the sheet 30. The sheet 30, however, is always the side wall 20 and flaps 22.

Referring to Figure 12, the base 102 is substantially planar. It has an inner face 104 facing the receiving space 16, and an outer face 106 facing away from the receiving space 16.

The outer face 106 is coated with a thermoadhesive coating 108, separate from the base 102.

This coating thermal adhesive 108 is made of a thermoadhesive material suitable for forming a bond with a compatible material when heated to a temperature above a threshold temperature. Said thermoadhesive material is preferably a hot-melt adhesive material at low temperature, that is to say that said threshold temperature is lower than 75 ° C. The threshold temperature remains above 58 ° C, so as to avoid any interaction between the thermoadhesive coating 108 and the food product 12 to the normal temperature food product shelf 12. The threshold temperature is typically a melting temperature of the thermoadhesive material .

The adhesive materials of thermoadhesive coating 108 and the thermoadhesive layer 42 are compatible materials.

In the example shown, the base 102 is identical to the cover 18. This facilitates the production of packaged portion 100. The sheet 30 has a rim 1 region 10 connected to the side wall 20 by the lower edge 26 of the last. This border 1 region 10 is folded and sealed in a sealed manner on the external face 106 of the base 102.

This embodiment of the bucket 14 in two parts (the sheet 30 and the base 102) is used to impart to the packed portion 100 an original form. In particular, this embodiment of the bucket 14 in two parts makes it possible to impart to the packed easily portion 100 of cylindrical revolution visible in Figures 10: 1 1 as it is more difficult to achieve with a bucket 14 in one part as is the case for the packaged portion 10. this embodiment of the bucket 14 makes it possible to obtain a cylindrical portion without any wrinkles on the side wall 20 and having the tearing guide strip 30 disposed in the sheet along the bottom edges 26 and top 24 of the side wall 20.

Another difference that shows the packaged portion 100 with respect to the packaged portion 10 is that the packaged portion 100 includes two gripping tabs 1 12 accommodated in the receiving space 16. A first of said tabs 1 12 is riding on the wall side 20 and the cover 18 being sealed to the lid 18 and the second slider 1 12 is riding on the side wall 20 and on the base 102 by being sealed to the base 102. These tabs 1 12 make it possible to facilitate removal the lid 18 and the base 102 by a consumer after lifting of the sidewall 20.

The packed portion of production process 100 is otherwise substantially identical to the production method of the packed portion 10. The only difference between these methods is the step of providing the bucket 14, which here comprises the steps of:

- folding the sheet 30 to form a tube, for example by winding the sheet 30 around a mandrel,

- introduction of the base 102 within the tube, the base 102 being oriented perpendicular to the tube axis until flush with the guide element 48 tears,

- folding the edge 1 region 10 of the outer face 106 of the base 102, and - heat-sealing the edge of Region 1 10 of the outer face 106.

For the description of the rest of the production method of the packed portion 100, the reader is referred to the description of the production method of the packed portion 10, Figures 14, 15, 16, 17 and 18 corresponding respectively to Figures 5, 6 , 7, 8 and 9.

With the method described above, it is thus possible to easily produce waterproof sealed portion packs of food products to be assayed cold without the packaged portion obtained presents peripheral flange. This process can also be easily implemented because it requires very little adaptation of existing production machines already used for the production of packaged food portions sealed dosed hot: most existing tools can indeed be reused, the main modifications to be carried out consisting in the addition of anti-static bars to limit the risk of droop associated with the employment of plastic, in the modification of the supply coils in the material constituting the lid, and adding an additional sealing station.