FR2773605A1 - Plate for cooking or reheating food in microwave - Google Patents

Abstract

The plate is made from a disc (12) 2 - 6 mm thick, made from a microwave-transparent material such as cardboard, a layer (2) of a microwave absorbing material in a recess in the disc formed by its raised flat rim (18), and a metallic heat-conducting layer (22) to receive the food product. The metallic layer is flat, extends to the edge of the disc and can be ribbed to form channels for removing moisture produced by defrosting product.

Description

Device for cooking or reheating food in a microwave oven
The invention relates to a device for cooking or reheating a pre-cooked food, fresh or frozen, in particular of the pie or pizza type, in a microwave oven.

Industrial, semi-fresh or frozen food preparations are enjoying increasing success due to their taste qualities and practicality sought after by consumers wishing to devote a limited amount of time to cooking.

In particular, frozen prepared meals are known, such as pizzas, savory pies, pies, quiches, etc., which all have in common the fact that they have a bottom in a dough, of the pie or bread dough type, on which a garnish.

The main drawback of frozen prepared meals of this type is the time required to reheat them, with or without additional cooking.

Indeed, to obtain a product ready for consumption and of good taste quality, it is imperative, in practice, to use a traditional oven. This requires preheating the oven for about 10 minutes, then reheating the frozen dish for another 25 minutes.

This total duration of more than 30 minutes is considered to be too long, both by consumers and by the manufacturers of these preparations.

It is certainly possible to accelerate reheating by thawing the food at room temperature, but this solution is not acceptable for consumers who choose, at the last moment, the frozen dish they wish to consume.

An object of the invention is to allow cooking or reheating of such frozen food in a limited time, of the order of 5 to 10 minutes, while retaining the taste qualities of this food.

It is clear that such a goal cannot be achieved with a traditional, electric or gas oven.

It is also known to reheat frozen food in a microwave oven. It is known in fact that the reheating time obtained with a microwave oven is short, due to the fact that the energy of the microwaves is communicated directly to the heart of the food itself.

Unfortunately, the taste quality of a pizza, pie, pie or quiche thus reheated is generally disastrous. Indeed, one obtains either a soft and moist food at heterogeneous temperature, if the cooking time is short, or a food whose bottom is dried and the filling has "turned" by boiling, if cooking is prolonged.

It turns out to be practically impossible to develop a reheating procedure in a microwave oven giving a reheated product with satisfactory taste qualities.

One of the main reasons is that the doughs, for bread or pie, are reheated at the heart of their mass by microwaves, which destroys their softness, whereas it would be advisable to brown their crust by a thermal shock, while gradually warming up their crumbs. In fact, the time for thawing and reheating the dough in the microwave should be short while the filling, which contains a lot of water, requires a longer reheating.

Under these conditions, it turns out to be impossible to find a satisfactory compromise.

Browning dishes are also known, in particular metal dishes provided with a sole based on ferrite powder (sintered metal oxides) or a layer sensitive to microwaves, transmitting high frequency energy into heat, and allowing d '' obtain a satisfactory result in a few minutes. These dishes very quickly reach a temperature of about 200 "C in a microwave oven. The food is thus heated, on the one hand by direct thermal contact of the dish with the dough, on the other hand by the microwave action on the filling.

However, these browning dishes have the disadvantage of being durable products, sold either as accessories with microwave ovens or as kitchen utensils. Such dishes are not universally available and are also too expensive to be individually added to a food of the tart, pizza or similar type, by the manufacturers of frozen products.

However, there is a strong demand from these manufacturers to provide their consumer customers with the means to efficiently and quickly heat frozen dishes and food, by giving them all the desirable taste qualities.

An object of the invention is to provide a device for cooking or reheating a precooked, fresh or frozen food, in particular of the pie, pizza or similar type, in a microwave oven with a time of rapid cooking or reheating, while retaining the taste qualities of the food.

Another object of the invention is to provide such a device, of the disposable type, capable of being produced at low cost.

The invention provides for this purpose a device for cooking or reheating a pre-cooked food, fresh or frozen, which comprises a tray or disc formed of a material transparent to microwaves, of the cardboard type or the like, and suitable for being placed in the oven; an absorbent layer of microwave absorbent material applied to an upper surface of the disc; and a heat conductive metal sheet, applied to the absorbent layer and suitable for receiving the food to be cooked or reheated.

This device thus resembles packaging, or additional packaging, of the disposable type. It is therefore a single-use or limited-use product that can be sold at the same time as the food.

Thus, pizza, pie or the like is sold in its packaging, being placed on the device in the form of a disc.

The latter makes it possible to directly heat the bottom of the dough by reproducing the traditional heating on an oven floor and to obtain a crispy crust on the surface and soft inside. In addition, the device makes it possible to heat the filling by direct effect of the microwaves and that until an ideal temperature.

In a preferred embodiment of the invention, the disc has a flat annular rim and raised relative to the upper face of the disc, so as to delimit a cavity used to collect the absorbent layer.

Preferably, the annular rim extends over a height, starting from the upper surface of the disc, which corresponds substantially to the thickness of the absorbent layer, this annular rim being covered by the metal sheet.

According to another characteristic of the invention, the material of the disc is a molded cardboard, in particular based on cellulose.

Typically, the disc has a thickness of between 2 and 6 millimeters.

The microwave absorbing material is a material containing one or more microwave absorbing elements.

 It is advantageously a mixture of the ferrites (sintered metal oxides) / silicone elastomer type.

According to another characteristic of the invention, the absorbent layer has a thickness of between 1 and 3 millimeters.

In one embodiment of the invention, the metal sheet is planar and extends to the periphery of the disc.

This metal sheet is preferably ribbed to form channels for the evacuation of the moisture resulting from the thawing of the food.

In another embodiment of the invention, the metal sheet has a raised peripheral edge, which is particularly suitable for reheating a pie, pie or quiche, the bottom of the dough has a continuous rim.

The aforementioned metal sheet is advantageously made of aluminum, known as food.

In another aspect, the invention relates to a method of manufacturing a device as defined above, this method comprising the following operations a) preparing a disc made of a material transparent to microwaves, of the cardboard type or the like, having a top surface conformed b) depositing an absorbent layer of microwave absorbent material on the upper surface of the disc; and c) applying a metallic foil to the absorbent layer.

According to an advantageous characteristic of the process, the absorbent material of operation b) is vulcanizable, and an operation d) is provided for vulcanizing the absorbent layer, by jointly ensuring a bonding by bonding of the absorbent layer with the disc and the sheet. metallic.

In the description which follows, given by way of example, reference is made to the appended drawings, in which - FIG. 1 is a partial view in diametral section of a cooking or reheating device according to the invention - FIG. 2 is a top view, on a reduced scale, of the device of FIG. 1 - FIG. 3 is a side view showing a device according to the invention placed in a microwave oven for heating a food of the pie or pizza type; and - Figure 4 is a sectional view, similar to that of Figure 1, for another embodiment of the invention.

First of all, reference is made to FIG. 1 which represents a cooking or reheating device 10 according to the invention which comprises a circular disc 12 formed of a material transparent to microwaves, of the cardboard type or the like and having a surface lower 14 and an upper surface 16. This disc has a thickness el which is typically between 2 and 6 millimeters, and it is provided with an annular rim 18, flat and raised relative to the upper face 16.

Thanks to its rim 18, the disc 12 delimits a circular cavity having a depth of 1 to 3 millimeters.

The aforementioned circular disc is advantageously produced by molding a packaging material, of the foodboard type, essentially formed from cellulosic fibers.

It is important to choose a material that is free of components likely to give off gases or vapors when placed in a microwave oven. It is therefore not recommended to use multi-layer type cartons.

On the contrary, it is preferable to use cardboard molded to the desired shape from cellulosic fibers. This molding technique also makes it possible to produce a disc having shapes and dimensions adapted to the product to be heated.

In the cavity delimited by the disc is deposited an absorbent layer 20 formed of a material containing elements absorbing the microwaves and having a thickness e2 corresponding substantially to the depth of the cavity.

The microwave absorbing material advantageously comprises a mixture of powdered sintered metal oxides (ferrites) and a thermoplastic, thermosetting or elastomeric material.

As ferrites, very particularly preferred are ferrimagnetic materials of general formula MO (FexOy) in which M is a bivalent metal, preferably Mn or Zn, and x and y are whole numbers, in particular x = 2 and y = 3.

These ferrimagnetic materials are ground so as to constitute a powder whose grains have a diameter of less than 250 micrometers.

This powder is then incorporated, in an amount of 30 to 80% by weight, into a thermoplastic, thermosetting or elastomeric material.

It is particularly preferred to use a silicone elastomer, since it is a vulcanizable product resistant to high temperatures and free of release of decomposition products.

The device 10 further comprises a metal sheet 22, conductive of heat, applied to the absorbent layer 20. This metal sheet has substantially the same diameter as the disc 12 and it optionally has a periphery 24 which covers the annular rim 18 of the disc .

This metal sheet is advantageously made of so-called food grade aluminum, that is to say of food grade aluminum. Thus, the device 10 is formed by the superposition of three elements, namely successively the disc 12 made of material transparent to microwaves , the layer 20 of microwave absorbing material and the metal sheet 22 conducting heat. Thus, the absorbent layer 20 is "sandwiched" between the disc 12 and the metal sheet 22.

This metal sheet is intended to receive a prepared food A, in particular a frozen food, of the type pie, pie, quiche, pizza or the like, having a bottom of dough
P on which rests a gasket G (shown in broken lines in Figure 1).

The metal sheet 22 has a thickness advantageously between 0.05 and 0.5 mm.

As can be seen in Figure 2, the metal sheet 22 is generally planar and further has radial ribs 26 forming channels for the evacuation of moisture resulting from the thawing of the food. These ribs 26 are arranged between flat parts 28 in the form of circular sectors.

To manufacture the device 10 of FIGS. 1 and 2, the disk 12 is prepared by an appropriate molding, compression or assembly technique, so as to give it a chosen shape and dimensions, and in particular a shaped upper surface suitable for defining a circular cavity.

Then the absorbent layer 20 is deposited on the upper face of the disc, filling the aforementioned cavity. For this, a vulcanizable mixture based on ferrite and silicone powder is advantageously used, as defined above.

Then applied the metal sheet 22 which covers the absorbent layer 20 and the annular rim 18 of the disc. Then, the mixture is vulcanized under more or less high pressure, while ensuring an intimate bonding of the absorbent layer 20 with, on the one hand, the disc 12 and, on the other hand, the metal sheet 22.

On the device 10 thus formed, it is possible to place the food A (FIG. 1), the whole being coated with a sealed film of plastic material, then placed in a packaging box.

To reheat the product, simply unpack the assembly, and place the food A on the device 10 directly on the turntable 30 of a microwave oven 32 (Figure 3).

Food A is reheated for a period of the order of 4 to 7 minutes, depending on its size and the power of the oven.

In the oven cavity, part of the microwaves (arrow F1) reflected from the bottom of the oven pass through the disc 12 and are absorbed by the absorbent layer 20, the temperature of which can then reach a value of the order of 200 "C The metal sheet 22 is heated, by thermal conduction, by the absorbent layer 20.

As this metal sheet is opaque to microwaves, the pastry base P of food A is not exposed directly to microwaves coming from below the turntable.

Another part of the microwaves (arrow F2) coming from above the oven directly heat the lining G.

Thus, the dough base P of the food A is heated by thermal conduction from the metal sheet, which makes it possible to obtain a crispy dough without moisture, the latter being discharged radially by the evacuation channels metallic foil.

The gasket G is heated to uniform temperature by the action of microwaves, without causing boiling given the relatively short time spent in the oven.

In the embodiment of Figure 4, the metal sheet 22 has a raised peripheral edge 34, which can be smooth or fluted like a pie pan. The metal sheet thus constitutes a kind of mold suitable for frozen foods of the type of thick pies or quiches, the dough of which has a continuous rim.

The edge 34 is also heated by thermal conduction which makes it possible to obtain a favorable browning of the rim of the food.

The device of the invention can be combined with a single frozen food or with several frozen foods in the same package.

Of course, the invention is not limited to the embodiments described above by way of examples and extends to other variants.

Claims (13)

Claims 1. Device for cooking or reheating a pre-cooked food, fresh or frozen, in particular of the pie or pizza type, in a microwave oven. characterized in that it comprises a tray or disc (12) formed of a material transparent to microwaves, of the cardboard type or the like, and suitable for being placed in the oven; an absorbent layer (20) of a microwave absorbing material, applied to an upper surface (16) of the disc and a heat-conductive metal sheet (22), applied to the absorbent layer (20) and suitable for receiving the food (A) to cook or reheat. 2. Device according to claim 1, characterized in that the disc (12) has an annular rim (18) flat and raised relative to the upper face (16) of the disc, so as to delimit a cavity used to collect the layer absorbent (20). 3. Device according to claim 2, characterized in that the annular rim (18) extends over a height, from the upper face (16) of the disc, which corresponds substantially to the thickness (e2) of the layer absorbent (20), and in that the annular rim (18) is covered by the metal sheet. 4. Device according to one of claims 1 to 3, characterized in that the disc material (12) is molded cardboard, in particular based on cellulose. 5. Device according to one of claims 1 to 4, characterized in that the disc (12) has a thickness (el) between 2 and 6 millimeters. 6. Device according to one of claims 1 to 5, characterized in that the microwave absorbing material is a mixture of the ferrite / silicone elastomer type. 7. Device according to one of claims 1 to 6, characterized in that the absorbent layer (20) has a thickness (e2) between 1 and 3 millimeters. 8. Device according to one of claims 1 to 7, characterized in that the metal sheet (22) is planar and extends to the periphery of the disc. 9. Device according to one of claims 1 to 8, characterized in that the metal sheet (22) is ribbed to form channels (26) for the evacuation of moisture resulting from the thawing of the food. 10. Device according to one of claims 1 to 7, characterized in that the metal sheet (22) has a raised peripheral edge (34). 11. Device according to one of claims 1 to 10, characterized in that the metal sheet (22) is made of aluminum. 12. A method of manufacturing a device according to one of claims 1 to 11, characterized in that it comprises the following operations a) preparing a disc (12) of a material transparent to microwaves, of the cardboard type or analogous, having a shaped upper surface (16); b) depositing an absorbent layer (20) of a microwave absorbent material on the upper surface of the disc; and c) applying a metal sheet (22) to the absorbent layer (20). 13. Method according to claim 12, characterized in that the absorbent material of operation b) is vulcanizable, and in that an operation d) is provided for vulcanizing the absorbent layer (20), by jointly ensuring a connection by gluing the absorbent layer with the disc (12) and the metal sheet (22).