FR2945282A1 - Fresh food product e.g. red meat, packaging and cooking assembly for micro-wave oven, has outer package provided with maintaining unit for maintaining movable lateral flaps in closed state until end of heating - Google Patents

Abstract

The assembly (1) has an inner package (7) closed by a sealing film (11) and containing a food product (5) to be heated and/or cooked. An outer package (9) has an opening through which the inner package is glided and removed. The outer package is provided with a maintaining unit for maintaining movable lateral flaps (13a) in a closed state until the end of heating by providing confined heating at certain threshold temperature and/or pressure before liberating opening of the flap. The film is covered by a retaining wall (9a) of the outer package. The sealing film is used as a DARFRESH(RTM: vacuum skin package type film). An independent claim is also included for a method for packaging and cooking a food product.

Description

The invention relates to an assembly adapted to be heated in a microwave heating chamber. Sold especially in the distribution in supermarkets, we already know such an assembly comprising an initially closed inner packaging, containing a food product to be heated and / or cook and comprising a stretch film, often called upper film which covers said product and is sealed for close the inner packaging.

A particular situation is related to the deformation of this film that occurs during heating. Even if it is not dangerous at first sight, this distortion is sometimes impressive, the film having a great capacity for stretching and then swelling a lot. The space available in the heating chamber also decreases. And a burst is always possible. The object of the invention is to take advantage of this situation in order to limit the visual impact of the swelling of the film and to improve the conditions of end of heating. A proposed solution to all or some of these disadvantages is that said film is covered by a retaining wall of an outer package that can be opened and closed and which at least partially doubles the inner packaging ensuring, while there is heating of these packages in the enclosure, a certain confinement in the space between the packages, as long as the outer packaging is closed. With this confinement, we will be able to manage (typically limit) the importance of the deformation and / or use its effect for the opening of the outer packaging.

To tend towards the satisfaction of the first point, it is advised that the outer packaging be less deformable than the aforementioned film at a given pressure generated, in the inner packaging, by heating the product (and therefore packaging) in the enclosure, so that this outer package is adapted to thwart the deformation under pressure of the film to the outside, at least as long as it is sealed. To tend towards the satisfaction of the second point, it is advised that the outer packaging integrates or is provided with a means of rupture of the confinement by which this packaging can be opened following a loosening of the film and / or an increase of the pressure in the inner packaging beyond a certain threshold generated by the heating of the packaging. Preferably, the aforementioned means of breaking the containment will comprise a movable flap carried by the outer package. Favorably, a closure means will hold closed, or substantially closed, this flap, as the deformation towards the outside of the film has not reached a determined threshold and / or the pressure in the inner packaging will not cause an opening in it, by heating the packages. Another aim is to condition, heat and inform the user that his hot product is ready and / or to promote the escape of steam when, typically, the seal which held the film tightly fixed breaks, releasing the pressure prevailing under the film.

For its conditioning before and during heating, it is known to place the food product in a first packaging adapted to be heated by microwaves and thus comprising a sealed film which closes the first packaging, this film being stretchable to the outside under a pressure prevailing in said first package.

In a complementary manner, the following is an important characteristic: to cover at least a portion of the first closed package with a second package that can be opened and closed and that is adapted to be heated by microwaves and to ensure that, while there is heating of these packages in the enclosure, a certain confinement in the space between the packages, as long as the outer package is held closed by a closing means, - place the whole in a heating chamber by means of micro- wave where it is heated to create: * first a deformation of said film, by swelling, the sealed film then being substantially confined in the second closed package, * then an opening of the outer packaging, the film being then unsealed, therefore deflated. Preferably, in order to favorably couple a limitation of the deformation, a use of its effect for the opening of the outer packaging and the information sought from the consumer, it is advisable: to make the second packaging in the manner of a box completely enclosing the inner package and which is provided with at least one movable flap through which said box can be opened and closed and slipped or pulled out the first package, 30 - and, for most of the time during which the packs are heated, to retain the movable shutter closed by the closure means, thus ensuring said sensitive confinement. Other characteristics and advantages of the invention will become apparent with reference to the appended figures in which the following can be seen, in a non-limiting and schematic manner: FIG. 1, the two packages, the second open, taken out of the oven in which the whole has has been heated so that the product is ready to consume, - figure 2, the inner packaging with the film attached to the product, - figures 3, 4, each an embodiment variant of all the packaged packaging, - figure 5 a detail of FIG. 1, seen from below 15 along the arrow V, FIG. 6, a view from below of the outer packaging of FIG. 1, FIG. 7, all of the two packagings packaged, with the product, in the heating chamber shortly before or at the end of the heating time that has been imposed by the user, - Figure 8, a developed flat of the outer packaging. 1 shows an assembly 1 adapted to be heated in a heating chamber 3a of a microwave oven 3. For this and the prior storage of the food product 5 it contains, the assembly 1 comprises a inner package 7 initially closed, enclosing the product 5 to be heated and / or baked, and an outer package 9 (90 Fig. 3) at least partially doubling the inner package.

The product 5 is typically a fresh product, possibly already slightly golden or precooked, such as a meat or a fish to cook or finish cooking. The invention however also applies to frozen foods.

As the heating is not completed or almost completed, the inner packaging 7 is closed by a stretch synthetic film 11. This film may in particular be a coextruded film suitable for vacuum packaging of fresh or frozen products. Just like all the components of the set 1, it is microwavable (adapted to be heated by microwaves). It forms a high barrier to oxygen. It may be the film DARFRESH (TM) superior film microwavable company CRYOVAC. In particular Figure 2, we see that the inner package 7 will favorably include a tray 15 in the bottom of which was placed here the food product 5 and which is closed by the stretch film 11. For the preservation of the product, this film It has been vacuum-plated around the product 5 and over the bottom 15a of the tray, at least before heating. As known per se, a previous vacuum setting will tightly (by plaxing), stretching, the film 11 around the product 5 and thus along the bottom and side walls of the tray 15. Heating and steam created then by the product will later inflate the film, the retaining wall 9, 90a ... to control its deformation hot, under pressure. Thus, the use of a Cryovac Darfresh type process is recommended which provides for an in-line thermoforming of rigid and flexible barrier laminates (here the elements respectively 15 and 11). In this way, vacuum trapping of a flexible barrier laminate 11 with a "second skin" effect will be obtained. A vacuum pump will first allow a vacuum with heating of the upper film 11 by a heating dome, to the required temperature and then, as part of a gentle ventilation process, the upper film will mold itself by adopting perfectly the shape of the product, after which it will be sealed by heat and pressure on the lower film (tray 15). According to an important characteristic, FIG. 1 or 3 shows that the stretched film 11 is covered (here above) by a retaining wall, such as 9a, 90a, which doubles this film, at a distance from it, in this state where it is plated on the product. This wall 9a or 90a belongs to the considered outer packaging, such as FIG. 1 or FIG. 3, which ensures that said wall is held on top of the film for at least a portion of the time during which an internal increase in the pressure in the closed inner package 7, following the placement and heating of said assembly in the enclosure 3a, will create a deformation of the film to the outside, this deformation being thwarted by said wall 9a or 90a. This retaining wall will thus ensure, while there is heating of the inner and outer packaging in the enclosure, a certain confinement in the space between the packages, as the outer package 9,90_ is closed. To control the swelling of the film 11, it is recommended that all the outer packaging be less deformable than the film itself, this at a given pressure generated, in the inner packaging, by heating the product and packaging in the enclosure , thus effectively counteracting the deformation under pressure of the film to the outside, at least as long as it is sealed. 1 or 4, the wall 9a, 90a is held in place since the outer package 9 (marked 900 Figure 4) is in the form of a sheath provided with at least one opening 9b or 900b on at least one of its ratings. Through this opening, the inner package 7 can be slid into, and removed from, the sheath, one of the side walls is thus defined by the aforementioned retaining wall.

Figure 1, we see that the sleeve in question is in a box containing the package 7 and is provided with at least one movable flap 13a through which can be opened and closed the opening 9b and therefore the box. Thus, a certain confinement will be able to be ensured inside the outer package as long as the shutter is closed, while there is heating said assembly in the enclosure. 3, the retaining / covering wall 90a of the outer packaging 90 laterally has a fixed peripheral skirt 90c, for example glued continuously, over the side wall of the tray 15 to create the desired confinement. Under the pressure of swelling of the film 11, and / or the moisture / internal vapor produced by the exudates and the heating temperature, it is expected that the attachment of all or part of this skirt is broken at the end of heating, a priori substantially during the loosening of the film and / or when the pressure is maximum. The same may be done on the relevant part of the box, as shown in Figure 1. Favorably and until then, the retaining wall of the chosen outer packaging will cover, to close it, the space above the box. 11, irrespective of the variant chosen, in particular those of FIGS. 1, 3, 4. It will thus preferably extend substantially parallel to and at the level of the open upper surface 19 of the tray (top of the side walls), so to act on the deformation of the film to the outside when the latter arrives substantially at this level, heating. A flat, rigid wall belonging to a parallelepiped box will be particularly suitable. Preferably, this retaining wall will comprise, or be made of, cardboard. Thus, it will combine low cost, ease of manufacture / formatting, compatibility with microwaves and food, mechanical and thermal stability, ability to carry a message for example advertising (printing or otherwise). Returning to the folded movable flap 13a of the packaging box, it is important, such as this boxed form. First, such a box, if the / each component allows to completely close the outer packaging, protects the inner packaging 7, or even facilitates packaging. In addition, shutter (s) closed (s), we will be able, during heating of the complete assembly in the enclosure, ensure some containment inside the outer packaging. Moreover, by managing / controlling, on heating, the conditions of opening / closing of this component (s), we can warn the user if his product is ready or not ready to be consumed. In order to favor all or part of these effects, it is recommended that the flap in question be held closed by a means of closure that is sensitive to the heat and / or the inflation pressure of the film 11. In particular, this means, 17 in the figures, may be adapted to allow the flap 13a to open by local delamination of the material of the outer packaging, such as that 9 figure 5.

Thus, the outer packaging will incorporate or be provided with a means of rupture of the confinement by which it can be opened following loosening of the film 11 [at a determined temperature and / or pressure (s)] and / or following a increasing the pressure in the inner packaging 7 beyond a determined threshold generated by the heating of the packages. 3, the use of a strip 17a of suitable glue, such as a polyamide glue, will create this means of rupture of the confinement, by breaking the moment of gluing between the skirt 90c and all or part of the side walls of the tray. Figures 1, 5, 6, the breaking means comprises the movable flap 13a carried by the package 9 and the closing means 17 holds closed, or substantially closed, as the heating has not reached a determined threshold and / or that the pressure in the inner package 7 does not cause an opening therein, by heating the packages. In particular, if the outer packaging is made of or based on cardboard, it will be preferable for the or each movable flap concerned to be retained closed on this packaging, as in FIG. 5, by a continuous or discontinuous adhesive strip existing between the shutter and a zone of the outer packaging that the latter covers, closed. The mark 17a in FIG. 5 shows a strip of discontinuous glue. Thus, seen from below as Figure 6, here with two side flaps 13a, 13b, these flaps will be closed, fixed outside the box, and not in, as often.

In other words, the or each movable flap will preferably be folded and closed on the outer package, such as 9, over the wall 9c of the outer package opposite to said retaining wall 9a. It will be understood that this wall 9c will be the bottom wall of the sheath, that is to say the one by which the said conditioned assembly is placed, thus avoiding the user being tempted to open it before heating. In practice, it is even advisable for the outer packaging to comprise two said openings, on two opposite sides, each of which can be closed and opened by a movable flap, here folded down, such as 13a, 13b, FIG. 6, one of them being retained closed on one area of the considered packaging with a lower mechanical strength than the other flap. Thus, at a given physical condition, such as a specific pressure, one of the flaps will open, thus breaking the confinement, the other not.

Without risking that the inner tray slips unexpectedly, since only one of the shutters will be open, the user will see the heat / vapor escape through the open flap (a priori arranged in front of him), the opening of the flap indicating that his product is ready. In addition, with the outer packaging in a thermal insulating material, such as cardboard, it will not risk burning itself out of the aforementioned assembly of the oven. In practice, to prepare the outer package to be closed, we can cut the agreed area of it to half-flesh and stick the shutter there, by an adhesive, allowing, if using cardboard, to ensure a ease of cutting and gluing in large series, low cost and with appropriate food compatibility. The zone concerned is marked 18 in FIG. 6, at the right of the adhesive strip, thus allowing delamination at the time of opening of the flap 13a. Figure 8, we see in 21a, 21b, two pre-cuts made through a portion of the thickness of the wall 9c of the bottom of the package 9, facing the flap 13a to control its control opening. This is a solution for the abovementioned half-flesh weakening which must favor the controlled opening here of the flap 13a. 23a indicates the direction of the fibers of the board, on the schematic plate: perpendicular to the direction 23b which passes through the two opposite flaps 13a, 13b. the package will preferably be in one piece, cut as appropriate (see illustration where the dashed lines such as mark the areas of folds made by thin lines of surface cuts). Due to the slight swelling of the outer package at least at the end of heating, which will generate an effort in particular on the means (17,17a) of controlled opening of this package, the area where this means is located a priori to influence the loosening zone of the film at the periphery of the support 15 which will be located nearby, even if the product would be off-center in this direction (thereby shortening the loosening distance of the film 11). By using all or part of the foregoing characteristics, it will therefore be possible to implement a method of packaging and cooking a food product in which: the food product 5 will be placed in a first package 7 adapted to be heated by microwaves. wave and comprising the film 11 closing this package (since vacuum-loaded in the case of the tray of Figure 2), then cover at least part of the package 7 with a second package, such as 9, 90 or 900, adapted also to be heated by microwaves, but made of a less deformable material, at the same pressure, as that of the first package 7, so that this second package can have, under pressure, an action on the deformation under pressure said film 11, - when the time comes, we will place everything (still closed box if we used the packaging 9) in the heating chamber 3a where it is heated by microwave, to create a deformation of said f ilm, by swelling, this deformation is therefore thwarted by a retaining action of the second package (which may still deform slightly under the pressure of the film), - then we will remove the whole from the enclosure, after said inflation of the 11 has caused (typically by back pressure) an opening of the first package 7 and therefore the deflation of the film. Figure 7 schematizes this, in connection with the use of the box 9. Typically, this deflation will be achieved by local loosening of the film at a location on the periphery of the tray 15, here preferably thermoformed. It will also be noted that with, for example, the hot-pressed shutter solution under pressure during the separation provided between the film and its support 15 (or following this separation), the solution presented here makes it possible: to integrate or to provide an outer package (9, 90 ...) of a steam escape means out of this second package (opening of the flap in the aforementioned example), and preferably to provide an opening of this outer packaging substantially At the time of the deflation of the film 11. In the foregoing, it will also be noted that during the above-mentioned steps of covering and heating: - the first package 7 will be favorably placed in a box, such as 9, enclosing it entirely and belonging to the second package, the box being provided with at least one movable flap, such 13a, to enter and exit the first package, - then we will have closed the / each flap, so as to ensure a certain confinement to the 9, as long as the shutter remains closed, while the said assembly has been heated in the enclosure, such as 3a.

Moreover, with regard not only to packaging and heating, but also to consumer information that its hot food product is ready, the foregoing has made it clear that: - first, and preferably, covered at least part of the first closed package 7 by the second packaging 9, 90 ... adapted, while there is heating said packaging in the enclosure 3a, to ensure a certain confinement in the space between the packages, this as long as the outer package is retained closed by its closure means, such 17, 17a, - then it was, when the time comes, placed all in the chamber 30 where the heating has generated: * first a deformation of the film 11, by swelling, this film, always sealed over its entire periphery, then being substantially confined in the outer package still closed, then an opening of this outer package, the film then being loosened, thus deflated. If the flap 13a is used, its retention in the closed state by the closure means 17, 17a will ensure the desired relative confinement. Thus, the closed means of holding the outer package until the end of the heating will be favorably sensitive to the heat and / or the inflation pressure of the film 11 and will thus ensure its function of closing and / or confining up to a certain threshold of temperature and / or pressure. Optionally a vapor exhaust means 30 other than such glued flap could be suitable. A valve, as is already known, could be used on the outer package.

In terms of implementation conditions, for a steak of beef about 100-150g pre-grilled for its surface to be marked, the heating in the enclosure 3a may last 50 to 70s, at 900W approximately.

It will also be noted that the upper film 11 could be sealed to a rigid or semi-rigid lower structure having a shape other than a tray, such as a flat plate.

Claims (13)

REVENDICATIONS1. Assembly (1) adapted to be heated in a microwave heating chamber, this assembly comprising an inner package (7) enclosing a food product (5) to be heated and / or baked and comprising a stretchable film (11) which covers said product and is sealed to close the inner package (7), characterized in that the stretchable film (11) is covered by a retaining wall (9a, 90a) of an outer package (9,90,900) which can be opened and closed and which at least partially doubles the inner packaging (7) ensuring, while there is heating of these packages in the enclosure (3a), a certain confinement in the space between the packages, as long as the outside package is closed. 2. Assembly (1) according to claim 1, characterized in that the outer package (9, 90, 900) which is less deformable than the stretch film (11) at a given pressure generated, in the inner package (7). ), by heating the packages in the enclosure (3a), is adapted to counteract the deformation under pressure of the film (11) outwardly, at least as long as it is sealed. 3. Assembly (1) according to claim 1 or 2, characterized in that the outer package (9, 90, 900) incorporates or is provided with a means of breaking the containment by which this package can be opened following a loosening of the film (11) and / or an increase of the pressure in the inner packaging (7) beyond a determined threshold generated by the heating of the packaging and the product. 4. Assembly (1) according to claim 3, characterized in that the means for breaking the containment comprises a movable flap (13a, 13b) carried by the outer package (9, 90, 900) and a closure means (17, 17a) holds closed, or substantially closed, as long as the heating has not reached a determined threshold and / or the pressure in the inner package (7) does not cause an opening (90b, 900b) in the by heating the packaging and the product. 5. Assembly (1) according to one of claims 1 to 3, characterized in that the outer package (9, 90, 900) is in the form of a box completely enclosing the inner package (7) and which is provided with at least one movable flap (13a, 13b) through which said box can be opened and closed, thus ensuring, shutter (s) retained (s) closed by a closure means (17, 17a), said desired confinement , while there is heating of the packaging and the product in the enclosure (3a). 6. Assembly (1) according to one of claims 4 or 5, characterized in that the or each movable flap (13a, 13b) is retained closed on the outer package (9, 90, 900) by a strip of glue (17a) continuous or discontinuous existing between the flap and a zone of the outer package (9, 90, 900) that it covers, closed. 7. Assembly (1) according to one of claims 4 to 6, characterized in that the closing means (17, 17a) which holds closed the movable flap (13a, 13b) is adapted so that the flap opens by local delamination of the outer packaging material. 8. Assembly (1) according to one of claims 4 to 7, characterized in that said or each movable flap (13a, 13b)) is closed on the outer package (9, 90, 900) over the wall of the outer package opposite to said retaining wall (9a, 90a) and which is the one by which said assembly (1) is laid. 9. Assembly (1) according to claim 1, characterized in that the outer package (9, 90, 900) is in the form of a box having two openings (9b, 900b) on two opposite sides, each of which can be closed and opened by a movable flap (13a) folded, one of them being retained closed on a zone of the outer package with a lower mechanical strength than that of the other flap (13b), so that on one condition determined physical, such as a predetermined pressure, one of the flaps (13a) opens, thus breaking the confinement, while the other (13b) does not open. 10. Assembly (1) according to one of the preceding claims, characterized in that the inner package (7) comprises a tray (15) in the bottom (15a) of which is placed the food product (5) and which is closed by said stretchable film (11), which is emptied or vacuum around the food product, over the bottom (15a) of the tray (15). 11. Assembly (1) according to claim 10, characterized in that the retaining wall (9a, 90a) of the outer package (9, 90, 900) extends substantially parallel to and at the level of the open upper surface ( 19) of the tray (15), so as to act on the deformation of the film (11) outwardly when the latter arrives substantially at this level, heating. 12. A method for packaging, heating and informing a consumer that a hot food product (5) is ready, wherein the food product is placed in a first package (7) adapted to be heated by microwaves. (3) and comprising a sealed stretch film (11) which thus closes said first package (7), said film being stretchable (11) outwardly under a pressure in said first package (7), characterized in that: at least a portion of the first closed package (7) is covered by a second package (9, 90, 900) which can be opened and closed and which is adapted to be heated by microwaves (3) and to ensure, while heating of these packages in the enclosure (3a), a certain confinement in the space between the packages, as long as the outer package is held closed by a closing means (17, 17a), the all in a microwave heating chamber (3a) (3) where it is heated up to first: deformation of said film (11), by swelling, the sealed film then being substantially confined in the second package (9, 90, 900) closed, then an opening of the outer package, the film being then loosened, so deflated. 13. The method of claim 12, characterized in that: - the second package (9, 90, 900) is made in the manner of a box (9) completely containing the inner package (7) and which is provided with at least one movable flap (13a, 13b) through which said box can be opened and closed and the first package slid or pulled out, and the movable flap (13a, 13b) is closed by the closure means (17, 17a); ), thus ensuring said sensitive confinement.