WO2008096388A1 - Container for cooking food - Google Patents

Abstract

The invention is a new container for food and for cooking food, entirely or partially made from a plastic film, provided with one opening (B) suited to be closed and hermetically sealed after the introduction of the food to be cooked and comprising at least one valve (L) made from a material having a lower melting point than said plastic film, so that the increase in temperature and pressure inside the container during the cooking of the food causes said valve (L) to open and part of the steam generated inside the container to be discharged.

Description

CONTAINER FOR COOKING FOOD

DESCRIPTION

The present invention concerns food containers and containers for cooking food, and in particular it concerns a new container for steam cooking with microwaves, made of a flexible plastic film provided with a breather valve for controlling pressure and temperature. The present invention can be successfully used in particular for the steam cooking of fresh vegetables in microwave ovens. The use of microwave ovens for cooking, defrosting or heating food is known and increasingly widespread. The known microwave ovens comprise a generator of microwaves that are diffused inside the cooking chamber, which is provided with insulating walls suited to prevent the waves from dispersing in the external environment.

Microwaves generate an alternate electric field that induces a vibration of the dipolar molecules contained in food, i.e. the water, carbohydrate and fat molecules that make up food, thus producing heat. The heat with which the food is cooked thus originates from a source that is inside the food itself, and not outside it, as is the case with traditional gas or electric ovens/hobs. The main advantage deriving from the use of microwave ovens is represented by the high cooking speed, in fact microwave cooking requires much less time than the traditional oven/hob cooking methods. This is also due to the fact that in traditional electric or gas ovens or hobs the heat generated by the resistances or by the flame must first heat the air in the cooking chamber, then the walls of the oven and of the container, and finally the food to be cooked. On the contrary, in microwave ovens the water contained in the food is heated and thus becomes an internal heat source that is inside the food and acts directly and only on the food itself. Microwave ovens are particularly appreciated because they allow food to be defrosted or warmed, and water and other liquid substances like milk to be brought to a boil very quickly.

Furthermore, the user is not forced to use specific pans or containers for cooking, rather, he/she can use the same plastic containers in which the the food is stored in the refrigerator or freezer. In this regard, plastic containers are known, which are made from a rigid plastic material transparent to microwaves. At present, a correct and balanced diet is considered one of the main factors in preventing the development and worsening of even serious diseases or intolerances and in guaranteeing generally good health conditions.

For example, it is known that food should be preferably cooked in a correct manner, without added fats, with no burnt parts and maintaining its original nutritional properties, in particular those of vitamins and mineral salts. In this regard steam cooking is widely appreciated, for example, as the nutritional substances present in the food being cooked are degraded and dissolved in water to a lesser extent compared, for example, to boiling.

Even steam cooking, however, as well as boiling, requires rather long times, involving considerable consumption in terms of fuel and electric energy.

Finally, for steam cooking the user needs to use at least two containers, one on top of the other, with the lower one containing water and the upper one containing the food to be cooked. It is also necessary to consider that, in any case, steam cooking generates a not negligible loss of nutritional substances, especially vitamins and mineral salts, that are washed away by

I the steam and that at the end of the cooking process are dissolved in the condensation water accumulated on the bottom of the lower container. This water is not used, but is successively eliminated as a waste, so that all the nutritional substances dissolved in it are definitively lost.

To overcome all the drawbacks described above, a new type of container for steam cooking with microwaves, with a breather valve for controlling pressure and temperature, has been designed and constructed.

The main object of the present invention is to propose a container that is suitable for containing food, in particular food with high moisture content, and for use in microwave ovens. Another important object of the present invention is to reduce to a minimum, during steam cooking, the degradation and loss of the nutritional substances contained in the food being cooked. Said steam cooking, in fact, takes place in the microwave oven that, using relatively low temperatures, near to the boiling temperature of water, does not cause the degradation of the nutritional properties of food due to excessive heat. Furthermore the food, even without adding fats, is neither burnt nor caramelized, as is the case, on the contrary, with traditional cooking in gas or electric ovens. Another important object of the present invention is to enable the food to be steam cooked while limiting the washing away and loss of nutritional substances in the condensation water, which is not eliminated as a waste but quickly re-absorbed by the food. Another important advantage offered by the present invention lies in that it reduces steam cooking times, thus also reducing electric energy consumption.

Another important advantage offered by the present invention lies in that the container can be closed and hermetically sealed, while the breather valve, preferably arranged along the container seal, ensures that the steam is let off once predetermined temperature and pressure values have been reached, with no risk of explosion or breakage of the container.

Another important advantage of the present invention, related to the fact that it is made of a flexible material, lies in that it can be folded before and after use, thus reducing its overall dimensions and facilitating its storage and disposal.

These and other direct and complementary objects are achieved by the new container for steam cooking with microwaves, with a breather valve for controlling pressure and temperature. The new container is made of a flexible film in a plastic material for food products, transparent to microwaves, particularly suited to contain fresh vegetables with high moisture content and to be used in microwave ovens.

In the preferred embodiment of the invention, the new container has substantially the shape of a bag, with sealed bottom and/or sides and at least one opening through which it is possible to introduce the food, suited to be closed and hermetically sealed, for example by heat sealing.

According to the invention, in particular, said plastic material of which the container is made can be heat sealed, at least on the inner side of the walls near said opening. The new container is preformed or made directly by the packaging machines during the packaging of the product. The new container comprises at least one temperature and/or pressure valve, preferably positioned along the sealed line of the container opening. Said valve, for example, is made of a layer of heat adhesive glue with a lower melting point than the material of which the container is made. Said layer of heat adhesive glue is applied by spreading or printing, using suitable equipment. As an alternative, said valve may be obtained by treating a section of the plastic film with a targeted electronic bombardment, in order to reduce its resistance to temperature and pressure.

Said valve made of heat adhesive glue is thus less tight and, if subjected to given temperature and/or pressure values, opens and lets out the steam generated inside the container. For cooking food, in particular fresh vegetables with a high moisture content, said food is introduced in the new container, which is closed and hermetically sealed and placed inside the microwave oven. After a few minutes in the microwave oven, set on suitable power values, the water contained in the food and in the container reaches the boiling point.

The increase in the temperature and pressure values inside the container, due to the boiling of water, causes said section of the layer of heat adhesive glue or of said portion treated with a targeted electronic bombardment to come off, that is, causes the valve to open, and a minimum part of the steam generated inside the container is discharged.

Said breathing action rebalances pressure and temperature inside the container, thus preventing it from exploding or breaking. The steam generated owing to the effect of the microwaves is agitated inside the container and, once in contact with the food contained therein, transfers its energy and condenses. In this way, the food is kept moist and the temperature is substantially constant, near 100⁰C. Only a small quantity of moisture is discharged from the container through said valve that, being rather small, in any case allows the pressure inside the container to remain high. In this way, also the steam temperature remains high and the steam is more saturated.

Therefore, the water originally contained in the food remains almost completely in the container, since the steam, once in contact with the food and the walls of the container, condenses and accumulates on the bottom of the container itself. Once the food is cooked, which takes an extremely short time, for example 6-7 minutes, the water accumulated on the bottom of the container, rich in nutritional substances, is quickly reabsorbed by the vegetables, thus replenishing them with the substances dissolved therein.

Said valve is preferably located on the upper part of the container, in order to enable the high-temperature steam to be discharged, so that the side walls of the container are not overheated and can be touched by the user with no risk of burning his/her hands. Furthermore, the high temperature of the upper part of the container facilitates the opening of the container's sealed line, in order to enable the successive extraction of the cooked food. The material used for making the container also ensures high flexibility and the container, when not in use, is not very bulky and can be comfortably stored and disposed of. The food cooked with the new container for steam cooking, therefore, maintains its nutritional properties, vitamins and mineral salts.

The taste, flavour and organoleptic properties of the food thus remain substantially the same and are not affected in any way, which does not happen when different cooking methods are employed.

The food cooked with the new container has a pleasant appearance, is neither dry nor partially burnt, and is rather soft.

Taste and flavour are enhanced, differently from traditional steam cooking or boiling.

The characteristics of the new invention will be highlighted in greater detail in the following description with reference to the attached drawings, which are provided as a non-restrictive examples.

Figures 1 and 2 show a possible embodiment of the new container for steam cooking with microwaves, respectively before and after cooking. Figures 3 and 4 show a possible further embodiment of the new container (C2) with a different configuration, respectively before and after cooking.

According to the embodiment shown in Figures 1 and 2, the new container (Cl) is made from a flexible plastic film sealed at the sides (M).

The new container (Cl) is provided with an upper opening (B) for introducing food, suited to be closed and sealed by heat sealing.

The breather valve (L), preferably located at the level of the sealable opening (B) of the container (Cl), is made of a layer of heat adhesive glue with lower melting point than the material used for making the container.

During cooking, the environment inside the container (Cl) reaches temperatures near 100⁰C and the pressure increases due to the effect of water evaporation. At given temperature and/or pressure values, said valve (L) opens as the heat adhesive glue (Ll) comes off, which enables the steam to be discharged.

Said valve (L) should be preferably located in the upper part of the container (Cl, Cl), so that the high-temperature steam, flowing out from above, overheats the upper sealed portion (B), thus facilitating its successive opening, while it does not overheat the sides (M) that can thus be touched by the user with no risk of burning.

Figures 5 and 6 show a further embodiment of the new container (C3) comprising a hollow part (C), made of a rigid or semirigid material, for containing the food to be cooked, and a covering film (F) made of a flexible plastic material and provided with a pressure valve (L).

Therefore, with reference to the above description and the attached drawings, the following claims are expressed.

Claims

1. Container for food and for cooking food, characterized in that it is entirely or partially made of a plastic film, comprising at least one opening (B) suited to be closed and hermetically sealed after the introduction of the food to be cooked and at least one valve (L) made from a material having a lower melting point than said plastic film, so that the increase in temperature and pressure inside the container during the cooking of the food causes said valve (L) to open and part of the steam generated inside the container to be discharged.

2. Container according to claim 1 , characterized in that said plastic film is transparent to microwaves.

3. Container according to claims 1 , 2, characterized in that said plastic film is flexible.

4. Container according to claims 1, 2, 3, characterized in that said plastic film can be heat sealed at least on its inner side near said opening (B).

5. Container according to claims 1, 2, 3, 4, characterized in that said valve (L) is made of a layer of heat adhesive glue having a lower melting point than said heat sealable flexible plastic film, and wherein said layer of heat adhesive glue is applied to a limited section of said opening (B).

6. Container according to claim 5, characterized in that said layer of heat adhesive glue is applied through spreading or printing.

7. Container according to claims 1, 2, 3, 4, characterized in that said valve (L) is obtained through the targeted electronic bombardment of at least one limited section of said heat sealable flexible plastic film near said opening (B), in order to lower the melting point of the material.

8. Container according to the preceding claims, characterized in that said valve (L) is located in the upper part of said container.