A method of packing a food product with extended shelf-life

The present invention is a method of packaging food in a paper or paperboard packaging container and heat-treating the food for the purpose of extending the shelf life of the food, wherein the method is before filling the food and. / Or at the same time, the packaging container is also filled with air bubbles containing non-oxidizing gas, and after such filling of the packaging container, the container is sealed by thermosealing, and the packaged food is heat-treated to extend the shelf life. The present invention relates to a method including an extension step.

Paper or paperboard packaging that is planned to be filled with food to be heat-treated in a closed packaging for the purpose of extending shelf life, generally to allow pressure equalization expansion of the food during heat treatment. , Fill the food, leaving only a part. The food product consists of, or at least partially contains, a liquid portion, which easily evaporates, thereby rapidly producing vapor or vapor pressure inside the packaging container to a certain level. The possibility of such expansion is particularly important if, at that level, the packaging can rupture, or even explode, at the sealed joint. Another reason for filling the packaging container with only a part left is that the free space above the height of the food is efficiently used to adjust the volume fluctuation in the food flow, which is likely to occur in the case of a defect in the filling machine. You can do it.

However, the unfilled space (so-called clearance) above the height of the food in the food-filled packaging container may carry a serious risk of the packaged product. The reason is that the ambient air that comes into contact with the food flow before and during the proper filling operation is easily taken up by the food flow into the packaging and enters the packaging along with the food flow. , There, it can accumulate and be trapped in this space. Contact between the air in such a trap capacity and the packaged food always causes a harmful oxidizing action on the food, and the oxidation of oxygen gas in the air causes the food to change or deteriorate in aroma and aroma as well as in appearance. The result is that it can be unattractive, even unsuitable for consumption. Such an oxidative destruction process occurs over time and varies from food type to food type. For foods that are particularly sensitive to oxygen, such as potatoes, asparagus, tuber crops, corn, fruits and pet food, such destruction processes occur very rapidly, while other, less oxygen-sensitive foods. Is retained for a longer period of time with no perceptible adverse effects.

Regardless of whether the food product that is packaged and whose shelf life can be extended in the packaging container by subsequent heat treatment is one type or the other type, the air trap capacity of the packaging container is as large as possible. It is desirable to carry out the filling operation under conditions where the amount is small and most preferably completely eliminated.

According to some prior art method, food filling is carried out under the supply of a non-oxidizing gas such as nitrogen, expelling air from the packaging and filling a gap above the height of the food with this gas. The gas is injected into the packaging container from one or more nozzles before and / or during the food filling operation. An example of such a prior art method is described in US Pat. No. 3,477,192. For filling during the simultaneous supply of non-oxidizing gas, it is necessary to close the packaging container immediately after filling in order to prevent new ingress of air into the packaging container. However, in practice, food filling is most commonly done at a different site than the subsequent closure of the food-filled packaging container, so this is because the packaging container, which is still open after filling, is said to be the packaging container. This means that the food must first be filled and transported a certain distance in contact with the ambient air before closing. Even if the transport time from filling to closing can be reduced, there is always time for at least a portion of the injected non-oxidizing gas to be extruded and replaced with air, and during this short transport the packaging There is a risk that there will be time to flow into the container. Therefore, such inflow air is simultaneously sealed in the packaging container and comes into direct contact with the food in the packaged container while the food in the opened packaging container is further stored.

According to the prior art method described in European Patent Publication No. EP 0008886 A1, the risk of air entrainment in a closed packaging container is such that the packaging vessel is in front of the food filling operation and / or said. Filling with air bubbles containing a non-oxidizing gas, such as nitrogen, at the same time as the work can effectively prevent, or at least significantly reduce. Therefore, according to European Patent Publication No. EP 0008886 A1, the opened packaging container is first filled with the gas-containing air bubbles in order to forcibly eliminate the air present in the packaging container, and then the food is filled to a desired height. Can be filled. After this filling, the clearance above the height of the food is more or less filled with air bubbles remaining inside, and thus remains in the packaging container even after closing. Packaging containers such filled with air bubbles and food are then heat treated (pasteurized) for the purpose of extending shelf life, i.e., food for a short period of time, at most about 100 ° C, usually 72-78. It can be subjected to heat treatment methods that are heated and maintained at a temperature of ° C. European Patent Publication No. EP 0008886 According to A1, the opened packaging container is first filled with the food to the desired height and then, or at the same time as the food is filled, above the height of the food in order to forcibly eliminate residual air. It is also possible to fill the remaining clearance of the gas-containing air bubbles. Packaging containers thus filled with air bubbles and food can then be closed, sealed and pasteurized to extend shelf life, as described above.

Examples of foods that can be packaged and heat-treated in a manner according to European Patent Publication No. EP 0008886 A1 are liquids such as brewed liquor such as beer and non-carbonated beverages such as non-effervescent beverages. However, European Patent Publication No. EP 0008886 A1 indicates whether solid or semi-solid foods such as potatoes, asparagus, tuber crops, corn, fruits, vegetables, meat, pet food, etc. can be used by the methods of the prior art. I haven't touched on it. It is also not clear from European Patent Publication No. EP 0008886 A1 whether such solid or semi-solid foods can be packaged and heat treated with liquids such as sauces, cooking juices and stocks.

However, one drawback of the prior art method according to European Patent Publication No. EP 0008886 A1 is that air bubbles trapped during food filling can be removed after subsequent heat treatment (pasteurization) and subsequent storage of the food. Even, until the time to open the packaging container, it tends to remain and accompany the packaging container more or less as it is. Therefore, residual air bubbles exposed when the packaging container is opened may give the packaged food a significantly foamy appearance, which causes improper storage of the food during the storage period in the packaging container. May be accompanied by deterioration of food quality. Problems specific to excess foam or air bubbles in opened packaging when packaged foods, such as non-carbonated non-effervescent beverages, are covered with foam or are not expected to be foamed at all in remote locations. Naturally, it will become more or less manifest.

<p><patcit num="1"><text>U.S. Pat. No. 3,477,192</text></patcit><patcit num="2"><text>European Patent Publication No. EP 0008886 A1</text></patcit><patcit num="3"><text>International Publication Number WO2003 / 035503</text></patcit></p>

<p> Therefore, for the purpose of extending the shelf life of food in a paper or paperboard packaging, the packaging is further opened without the risk of trapping air or oxygen in the packaging during food filling. There is still a need to be able to package and heat the food without the risk of adverse effects on the appearance of the filled food that is sometimes exposed. In particular, solid or semi-solid foods can be packaged with liquid foods such as sauces, cooking juices, stocks, etc., without the risk of harmful air or oxygen encapsulation, for the purpose of extending the shelf life of the food. There is still a technical requirement that there be no risk of such adverse effects on the food being heat-treated.</p>

<p> Therefore, an object of the present invention is to prevent the above-mentioned drawbacks and disadvantages of the prior art.</p><p> A further object of the present invention is in the packaging container in which an oxygen gas sensitive food can be packaged and heat treated in a paper or paperboard packaging container for the purpose of extending its shelf life, and air or oxygen comes into contact with the packaged food. The method is to be realized by means without the risk of being trapped in.</p><p> Yet a further object of the present invention is that both solid and semi-solid fruit products can be packaged and heat-treated in paper or paperboard packaging with liquid foods, with the risk that air or oxygen will be trapped in the packaging. Instead, it is to realize the type of method described in the introduction by means without the risk of being accompanied by the gas-containing foam as it is throughout the shelf life of the food.</p><p> These and other objectives and advantages are achieved in accordance with the present invention by a method having the characteristic properties as described in claim 1 of the attachment.</p><p> A practical embodiment for the purposes of the method according to the invention has characteristic properties as described in the accompanying dependent claims.</p>

<p> Therefore, according to the present invention, a method of packaging food in a packaging container made of paper or paperboard and heat-treating the food for the purpose of extending its shelf life, the method of which is before filling the food and. / Alternatively, in connection with the filling of the food, the packaging was also filled with air bubbles containing non-oxidizing gas, and after this filling, the packaging was closed by thermosealing, and the packaged food was subjected to heat treatment and closed. Realize a method that includes a step of extending its shelf life in a packaging container. The method is characterized in that the heat treatment is carried out at a processing temperature of at least 115 ° C.</p><p> Surprisingly, according to the present invention, the treatment temperature is at least about 115 ° C, i.e. the temperature at which heat treatment by pasteurization is usually performed (at most about 100 ° C, most commonly about 72-78 ° C). ), It has been demonstrated that after the packaging is closed and sealed, the residual air bubbles in the packaging can be effectively crushed and visually eliminated when the heat treatment is performed at a temperature significantly higher than).</p><p> The heat treatment performed at a treatment temperature of at least about 115 ° C is more heat resistant to harmful bacteria, so-called pathogens, as well as spores, compared to conventional pasteurization methods at most about 100 ° C. Higher sex microorganisms also enjoy the advantage of being broad and powerful enough to ensure eradication. Such a widespread and effective heat treatment gives the packaged food a much longer shelf life than the milder heat treatment at lower temperatures, thereby allowing the packaged food in an unopened packaging container. It also has the consequence of crushing and eliminating trapped air bubbles over a longer period of time during a viable shelf life.</p><p> According to one preferred embodiment, the heat treatment to extend the shelf life of the packaged food is a retort with a treatment temperature of about 120-140 ° C, using a treatment device already available and in a manner known per se. It is carried out inside. The heat treatment in the retort is usually carried out according to the batch method in order to minimize the required processing time of each batch to be treated, and the packaged food is agitated all at once to accelerate the heat transfer to the food. Can be done.</p><p> Foods subject to packaging and heat treatment using the methods according to the invention consist of, or include, slices or chopped elastically moldable fruits or vegetables, such as slices or chopped pineapples, apples, peaches, etc. In such cases, it is appropriate to first fill the packaging with the gas-containing air bubbles and then fill with such elastically moldable fruit and vegetable chopped pieces. Utilization of this filling sequence may result in unintentional but unavoidable trapping of air, especially in the cavities or air pockets formed between the inner wall of the packaging container at the corners and the chopping of fruits and vegetables. However, its elasticity effectively eliminates the risk of sealing traps in such air-filled cavities and pockets.</p><p> Foods subject to packaging and heat treatment using the methods according to the invention are solid meat, fish, fruits or vegetables, but consist of or contain slightly elastically moldable articles or chopped pieces. In the case of, the packaging container can first be filled with these articles to a desired filling height, and then the gas-containing air bubbles can be filled.</p><p>According to the present invention, regardless of whether the packaging container is first filled with air bubbles and then food, or conversely, first food and then air bubbles, or otherwise simultaneously filled with air bubbles and food. For example, in order to eliminate the risk of air remaining in this gap, when the packaging container is sealed by thermosealing, the entire container is filled with air bubbles in the gap above the height of the food in the packaging container. is important.</p><p> Foods to be packaged and heat-treated using the method according to the present invention are affected extremely rapidly, especially when exposed to air for a short period of time, or appear as early as after being exposed to air for a short period of time. If the oxygen gas-sensitive foods to be varied consist of, or include, for example, sliced, chopped or crushed pineapples, corn, peaches, etc., these foods have already been filled before filling the packaging. Is preferably protected with a bubble coating and then placed in the packaging container with the food coated. Such a protective bubble cover can cover the entire food container, which is variable immediately after washing, peeling and slicing, whereby the food can be filled in the packaging container with a conveyor belt or the like throughout the process. It can be transported without the risk of contact with ambient air.</p><p> The choice of foam or foaming agent, respectively, is not important to the present invention, but can be selected from a large number of technically known bubbles and foaming agents. Therefore, it is easy for those skilled in the art to select an appropriate foaming agent. However, preferably, the present invention needs to select bubbles or non-oxidizing gases, respectively, which have the least imaginable effect on the food. An unconstrained example of what can be used is nitrogen, but an inert gas such as argon can also be another example of such available gas.</p><p> Further objects, advantages and details of the present invention will become apparent from the following detailed description by reference to the accompanying drawings.</p>

<figref num="1">FIG. 5 is a schematic cross-sectional view of a prior art paper or paperboard laminate for packaging containers in a manner according to the present invention.</figref><figref num="2">FIG. 6 is a schematic perspective view of a prior art packaging container for use in a manner according to the present invention.</figref><figref num="3">It is the schematic of the 1st Embodiment of the method according to this invention.</figref><figref num="4">It is the schematic of the 2nd Embodiment of the method according to this invention.</figref>

The present invention will be described below with reference to the accompanying drawings in particular, but is not limited to these embodiments shown in the drawings and described below. It will be appreciated by those skilled in the art that a number of various modifications can be made by following the description above and below without departing from the concept of the invention, as defined in the appended claims. It is clear to.

FIG. 1 outlines a cross section of a packaging laminate known per se for the packaging container available in the present invention. The packaging laminate, indicated by common instruction number 10, has layers 11 of paper or paperboard, and outer liquidtight coatings 12 and 13 of the plastic, which only withstand heat resistance at a temperature of at least 120 ° C. It has sufficient heat resistance, and at the same time, it is useful for manufacturing packaging containers by thermo-sealing. The preferred plastic for both outer coatings 12 and 13 is polypropylene (PP). The packaging laminate 10 has a first gas barrier 14 and a second gas barrier 15 between one plastic coating 12 and a layer 11 of paper or paperboard, which are attached to each other via an adhesive layer 16 and another. It is connected to the adjacent layers 12 and 11, respectively, via an adhesive layer 17 and a laminate layer 18, preferably polypropylene (PP). Such prior art packaging laminates are described, for example, in International Publication No. WO 2003/035503.

From the packaging laminate 10 of FIG. 1, the food is packaged and heat-treated in a retort according to a predetermined time / temperature sequence at a processing temperature higher than 115 ° C, for example 120-140 ° C, for the purpose of extending shelf life. The resulting packaging can be manufactured by a method known per se. A typical such packaging container is a container which is outlined in FIG. 2 and is designated by Common Reference Number 20 and is manufactured by folding and thermosealing the packaging laminate. This type of commercial packaging is known under the Tetra Recart® trademark.

FIG. 3 schematically illustrates a first embodiment of a method according to the present invention. The type of opened packaging container 30 shown in FIG. 2 is transported by a moving conveyor belt to the first step in the direction of the thick arrow in the figure. In this step, the packaging container 30, indicated by the vertical down arrow, is filled with foam containing a foaming agent or blisters trapped with non-oxidizing gas. As shown in the figure, the packaging container 30 can be filled in the entire container, but it is not always necessary, and in a specific case, it may be sufficient to fill the packaging container 30 with air bubbles while leaving only a part thereof.

The appropriate filling height can be determined on a case-by-case basis, with particular consideration of the food in question. Bubbles, as already mentioned, for certain types of foods, such as slices or chopped pineapples, apples, peaches, etc., especially those containing slices or chopped elastically moldable fruits or vegetables. Packaging container 30 It may be necessary to fill the entire container, but for other types of food, such as slightly elastically moldable particles or chopped meat, fish, berries or vegetables, the packaging container It may be sufficient to fill a portion of 30.

The choice of foam and foaming agent, respectively, is not important to the present invention, but can be selected from a large number of technically known bubbles and foaming agents. Therefore, it is easy for those skilled in the art to select an appropriate foaming agent. However, preferably, the present invention requires the selection of foam or non-oxidizing gas that has the least imaginable effect on the food. An example of an unconstrained, available non-oxidizing gas is nitrogen, but an inert gas such as argon can be another example of such available gas.

After the introduction and filling of the bubbles, the packaging container 30 so filled is transported on the moving conveyor belt 31 to the second step in the direction of the thick arrow in the drawing. In this step, the packaging container 30 is filled with the food to a desired height. As shown in FIG. 3, and as previously described, the packaging container 30 is at a height below the open top edge of the packaging container, not over the entire container, during the mass elimination of a significant amount of air bubbles. It's just filled up. Spaces, crevices, above the height of the selected food in the packaging container 30, preferably air bubbles throughout the container after this food filling to ensure that no air remains in the filled packaging container. Need to be filled.

After the food filling operation, the packaging container 30 filled with air bubbles and food is transported on the moving conveyor belt 31 in the direction of the thick arrow in the figure to the third step, where the filled packaging container 30 is closed by thermosealing. Be done. When the packaging container 30 reaches the third step, if the clearance above the height of the food in the packaging container 30 is not completely filled with air bubbles for some reason, this is when the packaging container 30 is sealed. It may be appropriate or necessary to fill the packaging container 30 with additional air bubbles to ensure that the space is filled with air bubbles throughout the container. The replenishment of such air bubbles is, for example, that the air bubbles filled in the container in the second step have time to burst or collapse inside during transportation to the third step, or on the conveyor belt 31. It may be necessary due to air bubbles spilling out of the open top of the packaging container 30 for vibrating transport.

After being closed by thermosealing in the third step, the sealed packaging container 30 filled with food and air bubbles is used for heat treatment of the packaged food at a processing temperature of at least about 115 ° C to extend the shelf life of the food. It is further transported in the direction of the thick arrow in the figure to the subsequent process (heat treatment). The heat treatment for extending the shelf life of the food is preferably carried out in a retort 32 at a processing temperature of about 120-140 ° C. by a method well known to those skilled in the art.

FIG. 4 is a schematic illustration of a second embodiment of the method according to the present invention. The type of unpacked packaging container 40 shown in FIG. 2 is transported on the mobile conveyor belt 41 to the first step in the direction of the arrow in the figure. In this step, the packaging container 40 is filled with the food product to the desired height, as indicated by the vertical down arrow. For the reasons mentioned above, it is not desirable to fill the entire packaging container 40, and it is desirable to fill the entire packaging container with only a part remaining up to the food height below the upper end of the opened packaging container.

After the food is introduced and filled, the packaging container 40, which is partially filled, is further transported to the second step (air bubbles) in the direction of the thick arrow in the figure, in which step is not above the height of the food. The filling gap is filled with air bubbles while the air existing in the gap is forcibly removed all at once.

As in the first embodiment, the bubbles include bubbles, blisters or foaming agents trapped with non-oxidizing gas. The choice of foam or foaming agent, respectively, is not important to the present invention, but can be selected from a number of technically known bubbles and foaming agents. Therefore, selection of an appropriate foaming agent is easy for those skilled in the art. However, preferably, the present invention requires the selection of bubbles and non-oxidizing gases that have the least imaginable effect on the product. A preferred example of a non-oxidizing gas is nitrogen, but an inert gas such as argon can also be utilized in a manner according to the present invention.

The packaging container 40 is further transported on the moving conveyor belt 41 from the second step to the third step in the direction of the thick arrow in the figure for sealing by thermosealing. When the packaging container 40 reaches the third step, if the clearance above the height of the food in the packaging container 40 is not completely filled for some reason, this space will be used as the container when the packaging container 40 is sealed. It may be appropriate or necessary to fill the packaging container 40 with additional air bubbles to ensure that it is fully filled. The replenishment of such air bubbles is, for example, that the air bubbles filled in the container in the third step have already had time to burst or collapse inside during transportation to the third step, or on the conveyor belt 41. It may be necessary due to air bubbles spilling from the open upper end of the packaging container 40 for vibrating transport.

After being closed by thermosealing in the third step, the sealed packaging container 40 filled with food and air bubbles is used for heat treatment of the packaged food at a processing temperature of at least about 115 ° C for the purpose of extending the shelf life of the food. It is further transported in the direction of the thick arrow in the figure to the subsequent process (heat treatment). The heat treatment for extending the shelf life of the food is preferably carried out in a retort 42 at a treatment temperature of about 120-140 ° C. by a method well known to those skilled in the art.

Foods subject to packaging and heat treatment according to the present invention are oxygen sensitive to slices, chopped or crushed pineapples, corn, peaches, etc., which discolor and change appearance very rapidly as soon as they are exposed to air for a short period of time. If it consists of or contains food, it is preferable to protect the sensitive food from contact with ambient air already prior to filling the packaging. Thus, preferably, the food product is covered with a cover of air bubbles that is sprayed onto the sensitive food product immediately after washing, peeling and slicing, whereby the food product travels the entire process to the packaging container, such as on a conveyor belt. Can be transported without risk of contact with air until filling.

The present invention has been described in detail by reference to embodiments specifically described in the drawings, but is not limited to these embodiments and details. It will be apparent to those skilled in the art that a number of modifications and modifications can be made without departing from the scope of the concept of the invention so that the invention is limited to the appended claims.

The method according to the present invention requires heat treatment at a processing temperature of at least 115 ° C, for example, in a retort where food is provided for such heat treatment at about 120 to 140 ° C, for the purpose of extending the shelf life. It can be used for packaging foods in packaging containers. The method according to the invention is surprising that after such heat treatment and subsequent storage of the food in the unopened packaging, the air bubbles are substantially completely eliminated and are no longer visible when the packaging is opened. Providing the strengths to be.

10 packaging laminate 11 Paper or paperboard layer 12 Outer liquidtight coating 13 Outer liquidtight coating 14 First gas barrier 15 Second gas barrier 16 Adhesive layer 17 Another adhesive layer 18 Laminate layer 20 Schematic diagram of packaging container 30 Open packaging container 31 Mobile conveyor belt 32 retort seal 40 Open packaging container 41 Mobile conveyor belt 42 Retort