Food contained in a heat treatment package

Abstract

A method (400) for heat treating a food product (201) contained in a package (200) is provided. The package (200) is made of a packaging material (202) comprising a carton layer (203). The method (400) comprises exposing (402) the package (200) to hot water (212), thereby transferring heat (HT) from the hot water (212) to the food product (201), drying (404) the package (200) such that the water content in the carton layer (203) of the packaging material (202) is reduced, and exposing (406) the package (200) to cold water (214), thereby transferring heat (HT) from the food product (201) to the cold water (214).

Description

Technical Field

[0001] This invention relates to food processing. More specifically, it relates to heat treatment of food contained in packaging, including cardboard boxes. Background Technology

[0002] In the 1990s, technological advancements enabled the heat treatment of foods such as beans and chopped tomatoes within cardboard packaging. For example, at that time, Launched (Tetra The packaging involves food first being filled into cardboard boxes, then fed into, for example, a distillation station where both the food and the packaging undergo heat treatment. The same shelf life can be achieved by using cardboard boxes instead of tin cans, but the environmental impact is significantly reduced by using more sustainable packaging materials.

[0003] While distillation is commonly used for beans, peas, and similar foods, some foods, such as tomatoes, can also be processed using what's known as hot filling. When hot filling is used, as the name suggests, the food is heated and filled into packaging while still hot. The heat from the food, combined with its properties (such as its acidity level), kills bacteria, spores, and other unwanted microorganisms.

[0004] Exposing food packaging and the food contained therein to heat can have the positive effect of making the food safe to eat. However, heat exposure has negative effects on packaging materials. For example, printed decorations on packaging materials may deteriorate during heat exposure, especially when heat is provided by using steam.

[0005] A common solution to the problem of reducing the impact of heat exposure on packaging materials can be drawn from the tin can industry. To avoid negative impacts on printing during heat treatment, the packaging is heat-treated without printing (e.g., on a clean tin can), and then labeled after heat treatment. By labeling after heat treatment (i.e., on the printed packaging material), the risk is avoided.

[0006] In cardboard-based packaging intended to withstand heat treatment, it is known to have a plastic layer outside the cardboard layers. This allows the printed cardboard layers to be protected from steam or any other heat transfer medium by the plastic layer.

[0007] Despite the availability of different technologies, a problem remains that the packaging material can be damaged when heat-treated, particularly when steam is used to provide heat, on cardboard-based packaging filled with food. Summary of the Invention

[0008] One object of the present invention is to overcome, at least in part, one or more of the limitations of the prior art. Specifically, one object is to provide a method for ensuring adequate heat treatment of food while maintaining the integrity of the packaging material.

[0009] According to a first aspect, a method is provided for heat-treating food contained in packaging. The packaging may be made of packaging material including cardboard layers. The method may include exposing the packaging to hot water to transfer heat from the hot water to the food, drying the packaging to reduce the moisture content in the cardboard layers of the packaging material, and exposing the packaging to cold water to transfer heat from the food to the cold water.

[0010] By including the step of drying the packaging, water that may have seeped into, for example, the cardboard layer through the exposed ends of the packaging or through the protective layer can be removed before the packaging is re-exposed to water in the form of cold water. Removing water in this way can be considered as allowing the packaging to recover between the steps of exposure to hot water and exposure to cold water. As a result of this recovery, the packaging is less affected during heat treatment, which can lead to maintaining the integrity of the packaging and keeping the printed decoration in good condition for a longer period of exposure to hot and / or cold water.

[0011] The packaging may be exposed to hot water until the food temperature is in the range of 90°C to 130°C. The packaging may be exposed to hot water for 15 to 80 minutes. Exposing the packaging to hot water may include keeping the packaging indoors with a relative humidity in the range of 80% to 100%.

[0012] Drying may include maintaining the packaging in a room with an average temperature varying over time in the range of 10°C to 75°C. Drying may take at least 1 minute, or at least several minutes. Drying may take up to 30 minutes. Drying may include maintaining the packaging in a room with an absolute humidity less than half the absolute humidity of the room when the packaging is exposed to hot water. Drying may include maintaining the packaging at a relative humidity of less than 30%. Drying may include maintaining the packaging at a relative humidity of less than 50%, or less than the relative humidity of the room when the packaging is exposed to hot water.

[0013] The packaging can be exposed to cold water until the food temperature gradually decreases to below 50°C. More specifically, below 45°C for distillation stations and below 12°C for pasteurizers. The food can be exposed to cold water for 20 to 90 minutes. Exposing the packaging to cold water can include maintaining the packaging at a relative humidity of 80% to 100%.

[0014] The drying step may include generating an airflow in a chamber containing the packaging to remove the vapor from the chamber, thereby reducing the humidity in the chamber. The drying step may also include condensing water from the air in the chamber containing the packaging to provide reduced humidity in the chamber.

[0015] According to a second aspect, an apparatus is provided for heat-treating food contained in packaging made of packaging material including cardboard layers. The apparatus includes a chamber arranged to hold the food packaging; nozzles arranged to supply hot water to the chamber to expose the packaging to the hot water, thereby transferring heat from the hot water to the food, and to supply cold water to the chamber to expose the packaging to the cold water, thereby transferring heat from the food to the cold water; and an air circulation system for circulating air within the chamber and including a condenser for reducing air humidity to provide dryness when the packaging is located within the chamber, thereby reducing the water content in the cardboard layers of the packaging material.

[0016] According to a third aspect, a system is provided for heat-treating food contained in packaging made of packaging material including a cardboard layer. The system sequentially includes a heating station having a chamber arranged to expose the packaging to hot water to transfer heat from the hot water to the food; a drying station arranged to dry the packaging to reduce the water content in the cardboard layer of the packaging material; and a cooling station having a chamber arranged to expose the packaging to cold water to transfer heat from the food to the cold water.

[0017] According to the fourth aspect, a food product is provided that is contained in a food package obtained by the method according to the first aspect.

[0018] Both the device and the system have the same advantages as the method, and can include the same implementation schemes and features as the method.

[0019] Other objects, features, aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings. Attached Figure Description

[0020] Embodiments of the invention will now be described by way of example with reference to the accompanying schematic diagrams, wherein...

[0021] Figure 1 This is a flowchart of a method for heat-treating food contained in packaging.

[0022] Figures 2A to 2C The image shows packaging containing food during heat treatment, drying, and cooling.

[0023] Figure 3A and Figure 3B The graphs show the weight increase of the packaging caused by absorbed water and the change in edge wicking over time.

[0024] Figure 4 This is a flowchart illustrating a method for heat-treating food contained in packaging.

[0025] Figure 5 An apparatus for batch heat treatment of packaged food is shown.

[0026] Figure 6 A system for continuous heat treatment of food in packaging is shown. Detailed Implementation

[0027] Figure 1 This is a flowchart 100 illustrating a process for heat-treating food contained in packaging. In a first step 102, the packaging is stacked on a carrier or other equipment arranged to transport the packaging to a distillation station or other equipment used for heat-treating the food and containing the packaging. In a second step 104, the packaging is heated to a first temperature while placed in the distillation equipment. Next, in a third step 106, the packaging is further heated to a second temperature, typically higher than the first temperature. Both the second step 104 and the third step 106 may include spraying hot water onto the packaging. The hot water may be in liquid form or more or less gaseous (steam). During the second step 104 and the third step 106, heat is transferred to the food, thereby heating and killing microorganisms. Although two heating steps are described, this is only considered as an example. Furthermore, how the food is heat-treated—that is, the number of steps, the duration of different steps, the temperature, etc.—not only relates to food safety but also affects the taste and characteristics of the food. Therefore, different food producers may choose different combinations of heating steps.

[0028] Once the food and packaging have been heated, in step four 108, the packaging is dried. As will be explained in further detail below, this may include reducing humidity levels within the distillation station by using an air circulation system. The advantage of having a drying step is that it reduces negative impacts on the packaging materials.

[0029] Drying 108 can be carried out under atmospheric conditions and at a temperature of approximately 23°C. Drying can also be carried out at temperatures below this (e.g., below 20°C, below 17°C, or below 14°C). In each case, the temperature should still be above 0°C, preferably above 5°C. Drying at cooler temperatures may be advantageous because the moisture content of the ambient air can be lower, resulting in more dry air displacing the water evaporated from the cardboard layers in the packaging. This makes the drying of the packaging more efficient. When using lower temperatures, drying can be said to also include "cooling" because it cools the cardboard layers. Of course, hot air can also be used for drying, but in that case, it is preferable to ensure that the moisture content of the ambient air is not too high.

[0030] Subsequently, in step 110, the packaging is cooled. This can be achieved by spraying cold water onto the packaging. As for the steps of heating the packaging, namely steps 104 and 106, cooling can be divided into two steps, therefore, after step 110, step 112 can be performed, in which the packaging is further cooled. The cold water used in steps 110 and 112 can have different temperatures in the two steps. Furthermore, the duration and amount of water used between the two steps can differ.

[0031] In step 7, 114, the packages may be unstacked. This may involve opening the distillation station, removing the carrier from the distillation station, and moving the packages from the carrier to a conveyor belt or other downstream equipment for further processing.

[0032] Figures 2A to 2C Examples are shown respectively during heating (e.g.) Figure 1 The second step 104 or the third step 106 shown, during the drying of the package 200 (e.g., in the fourth step 108), during the cooling of the package 200 (i.e., in the fifth step 110 or the sixth step 112).

[0033] from Figure 2A Initially, packaging 200 includes food 201. Packaging 200 can be formed of packaging material 202 comprising a cardboard layer 203, an outer plastic layer 204, and an inner plastic layer 206. The cardboard layer 203 provides rigidity to the packaging. The cardboard layer can be a cardboard layer. The cardboard layer can be a fiber-based layer primarily made of cellulose. The outer plastic layer 204 protects the cardboard layer 203 from, for example, moisture from the surrounding environment, while the inner plastic layer 206 protects the cardboard layer 203 from the food 201.

[0034] When producing package 200, a longitudinal seal can be provided on the blank to form a sleeve. The sleeve can be closed at one end by a first transverse seal to form a bottom or top filled with food 201, and then closed at the other end by a second transverse seal to provide both a bottom and a top. Since package 200 is formed from a blank cut from a roll of packaging material, the carton layer 203 can be exposed in the top fins 208 and bottom fins 210 of package 200, i.e., there is no plastic layer covering the edges of the carton layer.

[0035] During heating, heat HT can be transferred to food 201 via packaging 200. As described above, heat HT can be provided by using hot water 212 as a heat transfer medium. Exposure to hot water 212 can continue until the food reaches a temperature T. HWithin the range of 90°C to 130°C, packaging 200 can be exposed to hot water for 15 to 80 minutes. Alternatively, packaging 200 can be exposed to hot water 212 by maintaining it at a relative humidity (RH) of 80% to 100%. When packaging 200 is exposed to hot water and thus heated, small amounts of water may sometimes penetrate the outer plastic layer 204 and enter the cardboard layer 203.

[0036] During the drying process, such as Figure 2B As shown, water W can be transferred away from packaging material 202. As illustrated, water W can be transferred from the packaging material via top fins 208 and bottom fins 210, and also from the carton layer via the outer plastic layer 204. This transfer through the outer plastic layer 204 depends on the type of plastic made of layer 204 and typically only occurs when the outer plastic layer 204 is warm.

[0037] Drying may include maintaining the package 200 at an average temperature T ranging from 10 to 75°C. D For a period of time. Drying can be carried out for at least 1 minute or at least 3 minutes. Drying can be carried out for up to 30 minutes. In addition, drying may include maintaining the packaging at an absolute humidity of 200 AH. D In the middle, the absolute humidity AH D Less than the absolute humidity (AH) when the packaging is exposed to hot water at a temperature of 212°C. H Half of the relative humidity RH. Drying may also or alternatively include maintaining the packaging at a relative humidity RH of less than 30%. In addition, drying may include maintaining the packaging 200 at a relative humidity RH of less than 50% of the relative humidity RH when the packaging 200 is exposed to hot water 212, wherein relative humidity should be understood as absolute humidity relative to the maximum humidity at a given same temperature.

[0038] Figure 2C Cooling of the package 200 shown can be achieved by spraying cold water 214 onto the package 200. Due to the temperature difference, heat HT can be transferred from the food 201 inside the package 200 to the surrounding environment. The package can be exposed to cold water 214 until the temperature T of the food 201 reaches a certain level. c Gradually reduce the temperature to below 50°C. More specifically, use a distillation station below 45°C and a pasteurizer below 12°C. Food 201 may be exposed to cold water 214 for 20 to 90 minutes. Exposing package 200 to cold water 214 may include maintaining package 200 at a relative humidity (RH) of 80% to 100%.

[0039] Figure 3AThis is a graph illustrating test results obtained when a drying step is used in a method of heat treatment of food contained in packaging as described herein. The type of packaging is similar to the packaging 200 described above, made of packaging material comprising a cardboard layer, an outer plastic layer, and an inner plastic layer. The cardboard layer has a thickness of 294 μm. The outer plastic layer has a thickness of 31 μm. The inner plastic layer is made of two layers of different plastic materials with a total thickness of 64 μm. The size (volume) of the packaging is 390 ml, and both the cardboard layer and the plastic layer are made of materials conventionally used for packaging in the technical field of heat-treated food contained in packaging. Specifically, the packaging is a medium-length 390 ml Tetra Pak package.

[0040] Drying was carried out at atmospheric pressure, room temperature of approximately 22°C, and relative humidity of 50%. The x-axis in the figure shows the drying time (in minutes). The y-axis shows the amount of moisture in the carton layers (in grams). The amount of moisture in the carton layers was determined by comparing the weight of the package with its weight prior to being filled with food and used in the method of heat treatment of the food contained in the package as described herein.

[0041] Figure 3B This is a graph showing test results obtained for the same packaging, but on the y-axis it shows edge wicking (EW) in mm. Edge wicking is the distance from the top seal (open edge of the carton) to the point where the carton layer can be observed to have absorbed water. For example, 10mm edge wicking means that water has penetrated 10mm into the carton layer, as measured along the plane of the carton layer from its edge. The edge of the carton layer coincides with the edge of the packaging material. Wicking is determined by studying the packaging from the outside, as it is clearly visible when the carton layer is affected by water or other liquids (causing it to darken). Several points are studied for each package and the average is calculated.

[0042] It can be seen that the increase in weight or the water absorption rate (in grams) decreases relatively linearly over time, following a curve described as y = -0.9969x + 5.8496, where y is the amount of water in grams and x is the drying time in minutes.

[0043] It can also be seen that edge wetting exhibits an exponential decrease, following a curve described as y = 45.079e -0.916x , where y is the edge wetting in mm and x is the drying time in minutes.

[0044] from Figure 3A and Figure 3B As can be seen, edge wetting decreases significantly faster, typically below 10mm after only 1 minute. This is a positive surprise, as edge wetting is primarily responsible for so-called "damp packaging," which is packaging in which the cardboard layers become so damp that they lose their rigidity and thus their ability to support and maintain the shape of the packaging.

[0045] In other words Figure 3A This demonstrates the weight gain of a type of packaging similar to the aforementioned packaging 200 after heat treatment and subsequent cooling for 0 to 5 minutes. During the cooling process, the packaging is in a dry chamber atmosphere. As can be seen from the figure, in this particular experiment, only a small weight gain is measured after approximately 5 minutes, meaning the initially measured weight gain decreases over time. Therefore, for the specific packaging used in this experiment, drying for 5 minutes allows most of the water transferred to the packaging material during the heating step, in which the packaging was subjected to water, to be dried out of packaging 200.

[0046] It has been observed that packaging materials with higher water content tend to be softer or damp, lacking the required rigidity compared to packaging materials with lower water content. Damage to the packaging 200 can be avoided or at least reduced by including a drying step during the heat treatment of the food 201 contained in the packaging 200.

[0047] Figure 4 This is a flowchart illustrating a general method 400 for heat-treating food 201. In a first step 402, packaging 200 is exposed to hot water 212, thereby transferring heat HT from the hot water 212 to the food 201. In a second step 404, packaging 200 may be dried, reducing the water content in the cardboard layer 203 of the packaging material 202. In a third step 406, packaging 200 may be exposed to cold water 214, thereby transferring heat HT from the food 201 to the cold water 214.

[0048] Drying 404 can be carried out under atmospheric conditions and at a temperature of approximately 23°C. Drying can also be carried out at temperatures below this (e.g., below 20°C, below 17°C, or below 14°C). In each case, the temperature should still be above 0°C, preferably above 5°C. Drying at cooler temperatures may be advantageous because the moisture content of the ambient air can be lower, resulting in more dry air displacing the water evaporated from the cardboard layers within the packaging. This makes the drying of the packaging more efficient. When using lower temperatures, drying can be said to also include "cooling," as it cools the cardboard layers. Of course, hot air can also be used for drying, but in that case, it is preferable to ensure that the moisture content of the ambient air is not too high.

[0049] Figure 5 An example illustrates an apparatus 500 for batch heat treatment of a package 200 containing food 201. The apparatus 500 may be a distillation station.

[0050] The device 500 may include a chamber 502 for holding the package 200. Although not shown, a door for accessing the chamber 502 may be provided. To provide hot water 212 and cold water 214, nozzles 504a and 504b may be provided inside the chamber 502. Valves 506a and 506b may be provided in the device 500 to enable and control airflow between the chamber 502 and the surrounding environment 507. To control the device 500, a control unit 508 may be provided. This control unit 508 may be configured, for example, to switch between different stages of heating, drying, and cooling, and also to continuously receive measurement data and adjust various operating settings accordingly.

[0051] Hot water 212 can be supplied into the equipment via hot water supply pipe 510, and in a similar manner, cold water 214 can be supplied via cold water supply pipe 512.

[0052] Alternatively, to enable effective drying of the package 200 within chamber 502, an air circulation system 514 can be used. This can be connected to the device 500 via valve 506a, as shown. The air circulation system 514 may include a condenser 516 arranged to release water from the air circulating in chamber 502, and a fan 518 arranged to provide movement of air through the air circulation system 514. Alternatively, humid air in chamber 502 can be exhausted while allowing more dry air from the surrounding environment to enter.

[0053] In order to release water from device 500, outlet 520 can be provided.

[0054] During the drying 404 step, an airflow AF can be generated to remove vapor from chamber 502, thereby reducing the humidity in the chamber.

[0055] As illustrated by condenser 516, the drying step 404 may include condensing water from the air to reduce the humidity in chamber 502.

[0056] Figure 6 A system 600 for heat treatment of food 201 contained in package 200 is shown. Unlike... Figure 5 The apparatus 500 and system 600 shown are examples of continuous heat treatment of food 201 contained in packaging 200.

[0057] In this particular example, package 200 can be conveyed on conveyor belt 602 through heating station 604, drying station 606, and cooling station 608. Heating station 604 may include chamber 610 and nozzles 612 for providing hot water 212, allowing food 201 to be heated to ensure the killing of bacteria and other unwanted microorganisms. Drying station 606 may be equipped with a fan 614 to provide air circulation. A valve 616 may be provided to allow humid air to be released from drying station 606. Cooling station 608 may be equipped with chamber 617 and nozzles 618 for providing hot water 214. Although not shown, system 600 may include, for example, Figure 5 The air circulation system shown.

[0058] Different stations can be equipped with gates for controlling humidity and temperature within their respective stations. These gates can be mechanically and / or pneumatically controlled, meaning they control airflow to prevent ambient air from entering and pre-existing air from being exhausted. Heating station 602 may have an inlet gate 620 and an outlet gate 622. Drying station 606 may have an inlet gate 624 and an outlet gate 626. Cooling station 608 may have an inlet gate 628 and an outlet gate 630.

[0059] As can be seen from the above description, although various embodiments of the present invention have been described and illustrated, the present invention is not limited thereto, but may be practiced in other ways within the scope of the subject matter defined in the appended claims.

Claims

1. A method (400) for heat-treating food (201) contained in a package (200), said package (200) being made of a packaging material (202) including a carton layer (203), said method (400) comprising: The packaging (200) is exposed to hot water (212), thereby transferring heat (HT) from the hot water (212) to the food (201). The packaging (200) is dried such that the moisture content in the carton layer (203) of the packaging material (202) is reduced, wherein the drying includes holding the packaging (200) in a chamber (502), an air circulation system (514) for circulating air in the chamber (502), and the drying is carried out at atmospheric pressure. The packaging (200) is exposed to cold water (214) to transfer heat (HT) from the food (201) to the cold water (214).

2. The method according to claim 1, wherein the packaging (200) is exposed to the hot water until the temperature (T) of the food (201) is reached. H (The temperature range is 90℃ to 130℃.) 3. The method according to claim 1 or 2, wherein the package (200) is exposed to the hot water (212) for 15 to 80 minutes.

4. The method according to claim 1 or 2, wherein exposing the package (200) to hot water (212) comprises keeping the package (200) in a room (502) with a relative humidity (RH) in the range of 80% to 100%.

5. The method according to claim 1 or 2, wherein the drying comprises maintaining the package (200) at an average temperature (T) that varies over time. D In a room (502) with a temperature range of 10 to 75°C.

6. The method according to claim 1 or 2, wherein the drying is performed for at least 1 minute.

7. The method according to claim 1 or 2, wherein the drying is performed for at least 3 minutes.

8. The method according to claim 1 or 2, wherein the chamber (502) has an absolute humidity (AH) during drying. D The absolute humidity (AH) of the room (502) is less than that of the package (200) when it is exposed to the hot water (212). H Half of ).

9. The method according to claim 1 or 2, wherein the drying comprises maintaining the package (200) at a relative humidity (RH) of less than 30%.

10. The method according to claim 1 or 2, wherein the drying comprises maintaining the package (200) at a relative humidity (RH) of less than 50%.

11. The method according to claim 1 or 2, wherein the drying comprises maintaining the package (200) at a relative humidity (RH) less than that of the chamber (502) when the package (200) is exposed to hot water (212).

12. The method according to claim 1 or 2, wherein the packaging (200) is exposed to the cold water until the temperature (T) of the food (201) is reached. H The temperature gradually drops to below 50°C.

13. The method according to claim 1 or 2, wherein the food (201) is exposed to the cold water (214) for 20 to 90 minutes.

14. The method according to claim 1 or 2, wherein exposing the package (200) to cold water (CW) comprises maintaining the package (200) in a relative humidity (RH) range of 80% to 100%.

15. The method according to claim 1 or 2, wherein the drying step includes generating an airflow in a chamber (502) holding the package (200) to remove vapor from the chamber (502) and thereby reduce the humidity in the chamber (502).

16. The method according to claim 1 or 2, wherein the drying step comprises condensing water from the air in the chamber (502) holding the package (200) to reduce the humidity in the chamber (502).

17. An apparatus (500) for heat-treating food (201) contained in a package (200), said package (200) being made of a packaging material (202) including a carton layer (203), said apparatus (500) comprising: The room (502) is arranged to hold the food packaging (200). The nozzle assembly (504a to 504b) is arranged as follows: - Hot water (212) is provided in the chamber (502) to expose the package (200) (402) to the hot water (212), thereby transferring heat (HT) from the hot water (212) to the food (201), and - Cold water (214) is provided in the chamber (502) to expose the package (200) (404) to the cold water (214), thereby transferring heat (HT) from the food (201) to the cold water (214), and An air circulation system (514) for circulating air in the chamber (502) and including a condenser (516) for reducing the humidity of the air when located in the chamber (502), thereby providing drying (404) of the packaging (200) to reduce the water content in the carton layer (203) of the packaging material (202), the drying being carried out at atmospheric pressure.

18. A system (600) for heat-treating food (201) contained in a package (200), said package (200) being made of a packaging material (202) including a carton layer (203), said system (600) comprising, in sequence: A heating station (604) is provided with a chamber (610) arranged to expose the package (200) to hot water (212), thereby transferring heat (HT) from the hot water (212) to the food (201). A drying station (606) is arranged to dry the packaging (200) such that the water content in the carton layer (203) of the packaging material (202) is reduced, the drying being carried out at atmospheric pressure, and A cooling station (608) is provided with a chamber (617) arranged to expose the package (200) to cold water (214) to transfer heat (HT) from the food (201) to the cold water (214); The system (600) further includes: An air circulation system (514) for circulating air in a chamber (502) and including a condenser (516) for reducing the humidity of the air when located in the chamber (502), thereby providing drying (404) of the packaging (200) and reducing the water content in the carton layer (203) of the packaging material (202).

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