JP7532059B2 - Packaged food and method for producing packaged food - Google Patents

Description

The present invention relates to a containerized food having a target food filled in a storage container and a film lid that seals the opening of the storage container, and a method for manufacturing the containerized food.

Patent document 1 describes a containerized food product that is produced by sealing the opening of a container that contains food with a sheet-like sealing lid.

Patent Document 2 also describes replacing the gas in the head space inside the storage container after the food is filled into the storage container. It describes that the gas replacement is performed using nitrogen gas, carbon dioxide gas, or a mixture of these gases. In this way, by replacing the gas in the head space inside the storage container, food deterioration can be prevented and the food can be stored for a long period of time after heat sterilization.

JP 2005-271935 A Japanese Patent Application Publication No. 10-310106

For example, when the head space in a storage container is replaced with nitrogen gas as in Patent Document 2, after the opening of the storage container is sealed with a sheet-like sealing lid, the sealing lid may become wavy after a certain period of time has passed, which may cause problems with the appearance of the containerized food.

On the other hand, when the gas replacement of the head space in the storage container was performed with carbon dioxide gas, the sealing lid rarely undulated after a certain period of time had passed after the opening of the storage container was sealed with a sheet-like sealing lid. However, carbon dioxide gas could be absorbed by the target food, and could also permeate a sealing lid made of a resin laminated film that does not contain aluminum foil in the laminated film, or a part of the storage container made of resin, and dissipate to the outside of the storage container. When such absorption or dissipation occurs, the internal pressure of the storage container decreases. At this time, there is a risk that the sealing lid will bend toward the target food as the internal pressure decreases, and come into contact with the target food and press against it. If the target food is, for example, a viscous food, there is a risk that the moisture (liquid) contained in the target food will seep out onto the surface of the target food when pressed by the sealing lid (occurrence of water release).

When water release occurs from the target food in this way, it causes problems such as spoiling the appearance of the containerized food when the sealed lid is opened, and the texture and taste become different from that of the original target food.

Therefore, the object of the present invention is to provide a packaged food product that is less likely to lose water from the food product, and a method for producing the packaged food product.

The first characteristic configuration of the containerized food of the present invention for achieving the above-mentioned object is that the target food has a viscous consistency and is filled into a storage container so that it is concave in vertical cross section, the target food has a film lid that seals the opening of the storage container, the head space within the storage container is filled with an inert gas , and the concavity of the surface shape of the target food in vertical cross section is defined based on the curve of the following equation 1 .

[Number 1]

According to this configuration, the target food is filled into the storage container so that the surface shape in a vertical cross section has a concave portion. After a predetermined time has elapsed after the production of the containerized food, the internal pressure of the container decreases when the inert gas is absorbed or dissipated, and at this time, it is possible that the film lid portion will bend toward the target food. However, with the above configuration, the concave portion of the surface shape of the target food and the curved shape of the film lid portion can be made to approximately match, making it easier to avoid contact between the target food and the lowest point of the film lid portion after the predetermined time has elapsed.

Therefore, in the containerized food of the present invention, since the film lid portion is less likely to come into contact with and press against the target food after the predetermined time has elapsed, it is possible to prevent the occurrence of syneresis, in which the moisture contained in the target food seeps out onto the surface of the target food. As a result, the containerized food is less likely to undergo syneresis even when the containerized food is stored for a long period of time, and the appearance of the containerized food is less likely to be impaired when the film lid portion of the containerized food is opened. Furthermore, by preventing the syneresis of the moisture contained in the target food, it is possible to prevent the target food from changing in texture or taste from being different from its original state.

In the examples described later, it is recognized that the shape of the film lid part after a predetermined time has elapsed after the production of the containerized food can be specified based on the curve of the above-mentioned mathematical expression 1. Therefore, if the surface of the target food in a vertical cross section can be formed into a concave shape along the planned shape of the film lid part calculated based on the curve of mathematical expression 1 with a desired gap therebetween, it is possible to prevent the target food and the film lid part from coming into contact with each other after the predetermined time has elapsed.

The second characteristic feature of the containerized food according to the present invention is that the food has the deepest recess in the center of the container when viewed from above.

This configuration makes it easier to reliably avoid contact between the target food and the film lid after the specified time has elapsed.

The third characteristic feature of the containerized food according to the present invention is that the depressions in the surface shape of the target food in a vertical cross-sectional view are arc-shaped.

With this configuration, the depression in the surface shape of the target food in a vertical cross section is defined as a simple arc shape, making it easy to form the surface shape.

A fourth characteristic feature of the containerized food according to the present invention is that the storage container is a resin container formed in a tapered shape that decreases in diameter toward the bottom when viewed in vertical cross section.

Such plastic containers are widely distributed for reasons such as the ease of stacking and storing each plastic container. Therefore, with this configuration, the present invention can be implemented on many plastic containers, and therefore the present invention can be widely applied.

A fifth characteristic configuration of the containerized food according to the present invention is that the film lid portion is made of resin or is a laminated film having a resin layer.

This configuration allows for the use of a film lid portion that can seal the opening of the container by welding the periphery to the opening, for example, using heat sealing.

A sixth characteristic feature of the containerized food according to the present invention is that the inert gas contains at least one of carbon dioxide gas and nitrogen gas.

According to this configuration, by replacing the gas in the headspace with an inert gas, deterioration of the target food is prevented, and the food can be preserved for a long period of time after heat sterilization.

A first characteristic configuration of the method for manufacturing containerized foods according to the present invention includes a filling step of filling a storage container with a viscous target food, a surface treatment step of shaping the target food so that it has a concave vertical cross-sectional shape, a gas replacement step of spraying an inert gas into the storage container to replace the gas in the storage container with the inert gas, and a sealing step of sealing the opening of the storage container containing the target food with a film lid , wherein the concave vertical cross-sectional shape of the target food is shaped to be an arc shape defined based on the curve of the following equation 1 .

[Number 1]

This configuration makes it possible to produce containerized food by filling a storage container with the target food so that the surface shape in a vertical cross-sectional view has a concave portion.

Furthermore, with this configuration, the concave shape of the target food in vertical cross section can be formed into an arc shape that follows the planned shape of the film lid part, with a desired gap, calculated based on the curve of number 1. In this way, with this configuration, the gap between the target food and the film lid part can be adjusted to an appropriate distance.

A second characteristic feature of the method for producing containerized food according to the present invention is that the target food is shaped using a pestle in the surface treatment step.

With this configuration, the pestle mold is lowered onto the surface of the target food and the lower end surface of the pestle mold is pressed against the surface of the target food, making it easy to form a surface shape that is concave in vertical cross section.

1 is a cross-sectional view showing a containerized food product according to an embodiment. 1 is a flow chart showing a manufacturing process of a containerized food according to an embodiment. FIG. 1 is a diagram showing an outline of a surface treatment process. FIG. 2 is a schematic cross-sectional view of containerized foods in Examples 1-1 to 1-3 and Comparative Example 1. FIG. 2 is a cross-sectional photograph of the subject food of the containerized food in Examples 1-1 to 1-3. 1 is a graph showing the results of the amount of water separated (wt %) in Examples 1-1 to 1-3 and Comparative Examples 1 and 2. 13 is a graph showing the results of measuring the film lid portion of the verification container in Example 2. 1 is a graph showing actual measured values and theoretical values in Example 2-1 (P=90). 1 is a graph showing actual measured values and theoretical values in Examples 2-2 and 2-3 (P=80, 70). 11 is a graph showing theoretical values for the width and length in Example 3.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in Figure 1, the containerized food X of the present invention has a viscous consistency, a target food 1 filled into a storage container 10 so that its vertical cross section is concave, and a film lid portion 12 that seals an opening 11 of the storage container 10, and an inert gas 14 is filled into a head space 13 within the storage container 10.

The target food 1 may be any food that is viscous, sticky, and high-density, such as, but not limited to, minced meat, processed meat products, baby food, cream, butter, paste, pate, and miso. In addition, these foods may be premixed with desired seasonings and gelling agents.

The target food 1 is filled into the storage container 10 so that it has a concave vertical cross section. That is, the target food 1 may be filled into the storage container 10 so that the surface shape 1a in the vertical cross section has a concave portion. The concave portion of the surface shape 1a is an area that is concave toward the bottom of the storage container 10 compared to the case of normal filling where the vertical cross section of the target food 1 is flat, for example (see FIG. 4). Thus, the "concave portion of the surface shape 1a in the vertical cross section" in the present invention is one that is designed to form a concave that can prevent the target food 1 and the film lid portion 12 from coming into contact after a predetermined time has elapsed after the containerized food X is produced.

After the specified time has elapsed, the internal pressure of the head space 13 will decrease when the inert gas 14 is absorbed or dissipated, and at this time, it is conceivable that the film lid portion 12 will bend toward the target food 1. However, with the above-described configuration, the recessed portion of the surface shape of the target food 1 and the curved shape of the film lid portion 12 can be made to roughly match, making it easier to avoid contact between the target food 1 and the lowest point of the film lid portion 12 after the specified time has elapsed.

The target food 1 is preferably filled into the storage container 10 so that the center of the storage container 10 is the deepest in the top view. The curvature of the film lid portion 12 after the predetermined time has elapsed is considered to be greatest at the center of the storage container 10 when viewed from the top, since the film lid portion 12 is curved with both ends fixed when viewed in cross section. Therefore, with this configuration, it is easy to reliably avoid contact between the target food 1 and the film lid portion 12 after the predetermined time has elapsed. Details of the surface shape 1a of the target food 1 in a vertical cross section will be described later.

The storage container 10 may be a molded container that can be distributed at room temperature or chilled and has sufficient practical strength. The storage container 10 may also have heat resistance that can withstand heat sterilization and barrier properties that can block oxygen gas. The container may be configured such that the film lid portion 12 can be sealed using, for example, heat sealing.

Such a storage container 10 can be made, for example, of a single material (e.g., resin), or can be made by laminating multiple resins. As the resin, known resins that can be used for food, such as thermoplastic resins such as olefins and polyesters, and biodegradable resins, can be used. Examples of olefin resins include polyethylene, polypropylene, ethylene-polypropylene copolymers, polybutene-1, and blends of these.
Examples of the thermoplastic polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and blends thereof. Resins such as polystyrene can also be used. These thermoplastic resins may be recycled materials. Examples of the biodegradable resin include microbial resins (a type in which microorganisms such as bacteria, mold, and algae use polyesters accumulated in the body during the metabolic process, including aliphatic polyesters such as biopolyesters, bacterial cellulose, and microbial polysaccharides such as pullulan and curdlan), natural products (those that have been modified to give thermoplasticity to chitosan, cellulose, starch, cellulose acetate, and starch), and chemically synthesized resins (those obtained by polymerizing chemically or biologically synthesized monomers).

Furthermore, in order to add gas barrier properties and oxygen absorbing ability, a gas barrier resin or a gas barrier resin and an oxygen absorbing resin can be laminated. Examples of gas barrier resins include ethylene vinyl alcohol copolymers and MXD6 nylon. Examples of oxygen absorbing resins include resins containing an oxygen absorber such as iron or ascorbic acid and a reaction accelerator, or resins containing an oxidizing polymer such as a polymer having an aliphatic carbon-carbon double bond in the main chain or side chain and an oxidation initiator. The volume of the storage container 10 is not particularly limited, but a volume of about 50 to 600 mL is easy to handle during retort sterilization.

In the case of a resin container such as a cup, tray, or pouch, the container 10 is preferably fabricated by laminating a thermoplastic resin layer such as polypropylene on the innermost layer on the food side and a resin layer such as polyester resin (polyethylene terephthalate, polybutylene terephthalate, etc.) on the outer side with an adhesive or by co-extrusion, but is not limited to this form. Instead of the resin layer, a deposition layer formed by depositing inorganic substances such as silicon oxide, ceramics such as alumina, carbon, etc. on polyester resin or polyamide resin by a known method such as chemical vapor deposition (CVD) or vacuum deposition may be used, or an oxygen barrier material formed as a coating layer made of a known barrier resin coating agent, or a known easy-to-tear resin layer may be used.

When the storage container 10 is made of paper in addition to resin, the resin is basically laminated on the innermost layer, so the sealing method is the same as for the resin storage container 10, where the film lid portion 12 is heat sealed. Also, the innermost surface of a metal can may be coated with resin, and the film lid portion 12 may be heat sealed in the same manner.

The storage container 10 has a flange portion 15 for welding the film lid portion 12, and is preferably a tapered resin container that is tapered toward the bottom in vertical cross section, which allows stacking and increases convenience during distribution and storage, but is not limited to this form. In addition, the resin container may be of various shapes, such as a circular or rectangular shape when viewed from above. The resin containers are widely distributed, for example, because they can be easily stacked and stored. Therefore, the present invention can be implemented in many resin containers, and can be widely applied.

The film lid portion 12 may be any film capable of sealing the opening 11 of the storage container 10, and a known method such as adhesion or welding may be used for the sealing method. For example, the film lid portion 12 may be formed from a resin film, and the periphery of the film may be heat-sealed with the flange portion 15 to weld it to the opening 11 of the storage container 10, thereby sealing the opening 11. In this case, the material of the film lid portion 12 is not particularly limited, as long as it is made of a resin such as polyethylene terephthalate (PET) or polypropylene (PP).

Alternatively, the film lid portion 12 may be a laminated film having a resin layer. In this case, it may be configured to have, for example, a resin layer such as PET, PP, or polyamide resin, a metal vapor deposition layer such as aluminum, aluminum foil, paper, or the like. Specifically, the film lid portion 12 may be formed by laminating PET, aluminum foil, and CPP (non-oriented polypropylene) in this order from the outer layer, or PET, aluminum foil, polyamide resin, and CPP in this order, but is not limited to these forms. Even when the film lid portion 12 is a laminated film having a resin layer, the opening 11 of the storage container 10 can be sealed by welding the periphery to the opening 11 using, for example, heat sealing.

In the containerized food X of the present invention, the head space 13 formed in the container 10 between the target food 1 and the film lid 12 is filled with an inert gas 14.

The inert gas 14 may contain at least one of carbon dioxide gas and nitrogen gas, but is not limited thereto, and may be an inert gas such as a mixed gas of carbon dioxide gas and nitrogen gas. Such a gas is filled into the head space 13 from a gas supply device via a syringe or the like, and then the storage container 10 is sealed. By replacing the gas in the head space 13 with the inert gas 14, deterioration of the target food 1 is prevented, and it can be stored for a long period of time after heat sterilization.

The surface shape 1a of the target food 1 in a vertical cross section may have a concave shape in the surface shape 1a in a vertical cross section of the target food 1. In this configuration, the concave shape in the surface shape 1a in a vertical cross section of the target food 1 is defined as a simple arc shape, so that the surface shape can be easily formed. The diameter defining the arc can be set to various dimensions, such as a dimension larger than the opening diameter of the storage container 10.

In addition, the concavity of the surface shape 1a of the target food 1 in a vertical cross section is defined based on the curve of the following equation 1.

[Number 1]

Since the film lid portion 12 is subjected to a uniform force in the direction inside the container 10, it is considered that the curved shape in side view will be similar to the curved shape in side view of, for example, an electric wire or the like that is fixed at both ends and subjected to gravity. The reason for this is that, when viewed from the side, both ends of the film lid portion 12 are fixed by heat sealing or the like, and when the internal pressure decreases, the film lid portion 12 is subjected to a uniform acting force (atmospheric pressure, gravity) from the same direction over its entirety and curves. Therefore, it is considered that it will have a curved shape similar to the electric wire or the like described above. It is known that the shape (catenary curve) in side view of such an electric wire or the like is represented by a catenary curve.

For example, a catenary curve with a vertex at coordinates (0, a) is expressed as "f(x) = a x cosh(x/a)", and when shifted in the y direction with y = f(x), it can be expressed as "f(x) = a x cosh(x/a) + b". Here, the two coordinate points where y = 0 are (W/2, 0) and (-w/2, 0). w corresponds to the aperture of the storage container 10, and the deepest position of the film lid portion 12 that has been curved and deformed due to a decrease in the internal pressure of the head space 13 is (0, c). c is the negative value of the recess depth at the center of the film lid portion 12, and b = c-1. If the cross-sectional shape passing through the center of the film lid portion 12 when the pressure is reduced is expressed as f(x), both ends of the cross section pass through c at (-w/2, 0) and (w/2, 0), so the cross-sectional shape can be expressed by the curve of the above formula 1. In this way, by measuring the opening diameter w of the storage container 10 and the recess depth c (negative value) of the center of the film lid portion 12 when curved and deformed, the shape of the film lid portion 12 a predetermined time after the containerized food X is produced can be determined by calculation.

Therefore, in order to avoid contact between the target food 1 and the film lid portion 12 after a predetermined time has elapsed after the container-packed food X is produced, the surface shape 1a of the target food 1 in a vertical cross section when it is filled into the storage container 10 can be specified based on the curve of the above-mentioned number 1 so that it does not come into contact with the film lid portion 12 after the predetermined time has elapsed. For example, if the surface of the target food 1 in a vertical cross section can be formed into a concave shape along the planned shape of the film lid portion 12 calculated based on the curve of the above-mentioned number 1 with a desired gap, it is possible to avoid contact between the target food 1 and the film lid portion 12 after the predetermined time has elapsed. It is difficult to completely match the shape of the target food 1 with the shape (planned shape) of the film lid portion 12 specified based on the curve of the above-mentioned number 1, and some unevenness is likely to occur. However, it is preferable to set the desired gap to, for example, about several millimeters (3 to 6 mm), because contact with the film lid portion 12 can be avoided even if there is variation in the shape of the target food 1 after filling.

As described above, in the containerized food X of the present invention, since the film lid portion 12 is less likely to come into contact with and press against the target food 1 after the predetermined time has elapsed, it is possible to prevent the occurrence of syneresis, in which the moisture contained in the target food 1 seeps out onto the surface of the target food 1. As a result, even if the containerized food X is stored for a long period of time, the containerized food X is less likely to undergo syneresis, and the appearance of the containerized food X is less likely to be marred when the film lid portion 12 of the containerized food X is opened. In addition, by preventing the syneresis of the moisture contained in the target food 1, it is possible to prevent the food from becoming hard due to syneresis, and it is also possible to prevent the texture and taste from differing from that of the original target food 1.

Even if the lowest point of the film lid portion 12 comes into contact with and presses against a part of the target food 1 after the specified time has elapsed, in the containerized food X of the present invention, the target food 1 is packed into the storage container 10 so that the vertical cross section is concave, so that the amount of water seeping out onto the surface of the target food 1 can be reduced compared to normal packing.

The method for producing a containerized food of the present invention includes a filling step 01 in which a viscous target food 1 is filled into a storage container 10, a surface treatment step 02 in which the target food 1 is shaped so that its vertical cross section is concave, a gas replacement step 03 in which an inert gas 14 is sprayed into the storage container 10 to replace the gas in the storage container 10 with the inert gas 14, and a sealing step 04 in which the opening of the storage container 10 containing the target food 1 is sealed with a film lid 12 (Figure 2).

In the filling step 01, a target food 1 having a viscous consistency, such as raw minced meat, is filled into the storage container 10. The filling may be performed, for example, through a filling nozzle, but is not limited to this method and any known method may be used.

After the target food 1 is filled into the storage container 10, a surface treatment step 02 is performed to shape the target food 1 so that its surface shape 1a in a vertical cross section is concave (FIG. 3). This shaping can be performed, for example, by using a pestle mold 20 to press the target food 1, but is not limited to this form and may be performed manually using a spatula or the like. In this embodiment, the case in which the pestle mold 20 is used will be described.

For example, when the target food 1 is filled into the storage container 10 through the filling nozzle 21, the surface shape 1a of the target food 1 in a vertical cross section is often not flat but convex (the center in a top view is the most convex). At this time, the pestle mold 20 is lowered onto the surface of the target food 1, and the lower end face of the pestle mold 20 is pressed against the surface of the target food 1 to form the surface shape so that the vertical cross section is concave. The lower end face of the pestle mold 20 pressed against the surface of the target food 1 has a shape corresponding to the surface shape 1a of the target food 1 in a vertical cross section. For example, if the concave of the surface shape 1a of the target food 1 in a vertical cross section is arc-shaped, the surface shape 1a of the lower end face of the pestle mold 20 in a vertical cross section has a shape that is convex like an arc. Also, if the concave of the surface shape 1a of the target food 1 in a vertical cross section is specified based on the curve of the above-mentioned number 1, the lower end face of the pestle mold 20 has a shape specified based on the curve of the number 1.

After the surface treatment process 02, a gas replacement process 03 is performed in which the gas in the storage container 10 is replaced with an inert gas 14. The inert gas 14 may contain at least one of carbon dioxide gas and nitrogen gas, but is not limited to these, and may be an inert gas such as a mixed gas of carbon dioxide gas and nitrogen gas. Such a gas is sprayed into the storage container 10 from a gas supply device via a syringe or the like.

After the gas replacement process 03, a sealing process 04 is performed in which the opening of the storage container 10 is sealed with the film lid portion 12. For example, when the film lid portion 12 is formed of a resin film, such sealing can be performed by welding its periphery to the opening 11 of the storage container 10 by heat sealing, but is not limited to this embodiment.

After the sealing step 04, a sterilization step 05 is performed in which the storage container 10 is heated and sterilized. The sterilization step 05 is intended for the purpose of cooking the containerized food, processing it, or distributing it for a specified period of time and under specified conditions. If the target food 1 is, for example, raw minced meat, it can be cooked by heating in the sterilization step 05. For example, if the purpose is distribution at room temperature, the sterilization step 05 may be performed under conditions that can sterilize heat-resistant bacteria as well.

The sterilization in the sterilization step 05 is preferably a retort sterilization treatment, but is not limited thereto. The retort sterilization treatment refers to a pressurized heat treatment, in which a product filled in a heat-resistant container is pressurized so that the container is not damaged by the internal pressure of the product due to the rise in product temperature, and is heated with steam or hot water at about 110°C to 130°C for about 10 to 50 minutes, so that the _F0 value is at least 3.1 minutes. The retort sterilization treatment can be performed using a batch-type retort sterilization device or a continuous-type retort sterilization device, and the sterilization step 05 can be performed using, for example, a hot water type pressurized heat sterilizer or a pressurized pressure cooker.

Example 1
An embodiment in which packaged food X is produced by the method for producing packaged food of the present invention will be described below.

Target food 1 was prepared by mixing 4,000 g of pork thigh meat, 108 g of salt, 17 g of κ-carrageenan (gelling agent: manufactured by Sansho Co., Ltd.), 116 g of tapioca starch (gelling agent: manufactured by Sanwa Starch Industry Co., Ltd.), 1,168 g of pork back fat, and 400 g of water to prepare a viscous food. This target food 1 was filled into a container 10, an Oxyguard cup (LRX84-105W, opening diameter 73 mm, manufactured by Toyo Seikan Co., Ltd.) that is circular when viewed from above, using a filling nozzle 21 (filling process 01). The amount of food filled into each container was adjusted to 77 g.

After the filling step 01, the surface of the target food 1 was pressed with a pestle mold 20 to form the surface shape of the target food 1 (surface treatment step 02). The pestle mold 20 was prepared in advance so that the surface of the target food 1 would have a predetermined distance (depth D) from the flat surface (D(0)) during normal filling (position where the distance H from the flange portion 15 of the storage container 10 (FIG. 4) is 6 mm) and the center of the storage container 10 would be the deepest in the top view. At this time, the pestle mold 20 used had a surface shape 1a in a vertical cross section of the lower end surface that was convex in an arc shape. The depth D of the recess was 6 mm (Example 1-1: D(6)), 11 mm (Example 1-2: D(11)), and 16 mm (Example 1-3: D(16)) (FIGS. 4 and 5).

After the surface treatment process 02, 100% carbon dioxide gas, which is an inert gas 14, was sprayed into the storage container 10 from a gas supply device via a syringe (gas replacement process 03).

After the gas replacement process 03, the opening of the storage container 10 was sealed by heat sealing with the film lid 12 (sealing process 04). The film lid 12 was a laminated film (manufactured by Toyo Seikan Co., Ltd.) formed by layering PET (9 μm), aluminum (20 μm), and CPP (30 μm) in that order from the outer layer. The heat sealing was performed using a heat sealing device (SN-2S type: manufactured by Shinwa Kikai Co., Ltd.).

After sealing process 04, the storage container 10 was heated to 121°C and subjected to retort sterilization for 20 minutes (sterilization process 05).

In this way, the method for manufacturing containerized food of the present invention was able to produce containerized food X in which the target food 1 was filled into the storage container 10 so that the center of the storage container 10 had the deepest recess when viewed from above.

The containerized food X (Examples 1-1 to 1-3) prepared as above was examined for the presence or absence of water syneresis (N=3). As comparative examples, the presence or absence of water syneresis was examined for a case having a flat surface D(0) as in normal packing (Comparative Example 1) and a case in which the surface shape 1a in the vertical cross section exhibits a convex shape of 6 mm from the flat surface D(0) as in normal packing (Comparative Example 2: D(-6)). The presence or absence of water syneresis was determined by determining whether water present in the head space 13 of the containerized food X after a predetermined time had elapsed since preparation, as described below.

After storing the prepared containerized food X for two months under conditions of 30°C and 80% RH, the film lid 12 was opened about halfway, the container 10 was turned upside down and left to stand for about five minutes, and the water released from the container 10 was collected and the weight of the water released was measured. The results of the amount of water released (weight %) are shown in Table 1 and Figure 6.

As a result, it was found that the amount of water syneresis was 0.26-1.86% in Examples 1-1 (D(6)) to 1-3 (D(16)), and the amount of water syneresis decreased as the depth D of the recess increased. From this, it was found that the greater the depth D of the recess, the more difficult it is for the film lid portion 12 to press the target food 1 after the specified time (two months) has elapsed, and therefore it is possible to prevent the occurrence of water syneresis, in which the moisture contained in the target food 1 seeps out onto the surface of the target food 1, and it is also possible to prevent the target food 1 from becoming hard.

On the other hand, in Comparative Example 1 (D(0)), the amount of water released was 2.94% or more, which was found to be 1.58 to 11.3 times greater than in Examples 1-1 to 1-3. In Comparative Example 2, the amount of water released was 3.81% or more, which was found to be 2.04 to 14.6 times greater than in Examples 1-1 to 1-3. In particular, in Comparative Example 2 (D(-6)), the surface shape 1a in the vertical cross section was 6 mm convex, which made it easy for the film lid portion 12 to press against the target food 1 during the storage period, and it was found that the amount of water released was significantly increased. In addition, Comparative Examples 1 and 2 were harder than Examples 1-1 to 1-3.

In addition, in the above containerized food X, the inert gas 14 was carbon dioxide gas, but similar results were obtained when the inert gas 14 was replaced with nitrogen gas, or when a mixture of carbon dioxide gas and nitrogen gas was used (results not shown).

Example 2
Consideration was given to a containerized food X in which the depression in the surface shape 1a of the target food 1 in a vertical cross section is defined based on the curve of the above-mentioned mathematical expression 1, which is based on a catenary curve.

When the internal pressure of the head space 13 decreases after a predetermined time has elapsed after the production of the containerized food X, the film lid portion 12 curves toward the target food 1. Whether the shape of the film lid portion 12 at this time can be defined based on the curve of the above-mentioned equation 1 was verified by measuring the film lid portion 12 after the predetermined time has elapsed. In this verification, a verification container filled with water instead of the target food 1 and sealed with the film lid portion 12 was used. Even if the content contained in the verification container is water, it is thought that the film lid portion 12 will behave in the same way as when the target food 1 is contained (curving toward the filled water side). Therefore, the verification container used in this verification was produced by applying a method similar to the manufacturing method of the containerized food described above, except that it was filled with water instead of the target food 1.

As a container for filling water, a plastic cup LRX84-105W (diameter 73 mm, depth 32 mm: manufactured by Toyo Seikan Co., Ltd.) with a circular top view was filled with 80 g of water, and then the gas in the head space 13 was replaced with a mixed gas (P=90) of carbon dioxide and nitrogen gas = 90:10 as the inert gas 14. The film lid portion 12 (20 μm PET / 7 μm aluminum foil / 70 μm CPP) was heat sealed with the above-mentioned heat sealing device, and the above-mentioned sterilization process 05 was carried out to produce a verification container simulating containerized food X.

The curvature of the film lid portion 12 of this verification container was measured using a Contracer CV-2100M4 (manufactured by Mitutoyo Corporation). Specifically, the top surface of the film lid portion 12 was swept, and the vertical (depth) position x and the horizontal position y were recorded. The results are shown in Figure 7.

The two black arrows in Figure 7(a) indicate the opening of the heat-sealed container for testing, and this sealing position is almost equal to the inner diameter of the container, and because it is the most raised, the vertical position x of these black arrows is at its maximum value. Figure 7(b) is a graph converted by moving the two black arrows in Figure 7(a) evenly toward the center of the container, with the center area set to zero.

The center of the highest position (position indicated by the black arrow) was set as the zero point, and the recess depth at the center of the film lid portion 12 was set as c (a negative value). The value obtained by calculating Equation 1 above was plotted as a theoretical value in Figure 8 as a solid line (P = 90: Example 2-1).

As a result, the curve shapes of the actual measured values (dashed line) and the theoretical values (solid line) were very similar. The degree of agreement between these curves was calculated based on the following formula 2.
This formula was derived based on the definition formula of the deviation ratio (reference literature "Clarification of the theoretical issues of the ATS method by the similarity relationship of the temperature history curve" Isamu Mukai, Zhu Zheng, Journal of the Japanese Society of Food Technology Vol. 16, No. 3, pp. 209-217, Sep. 2015).

[Number 2]

In equation 2, n is the number of digital data, i indicates the order of the theoretical and measured values, and the sum is calculated from i = 1 to n before being divided by n.

As a result, the degree of agreement of the above curves was calculated to be 92.1%. Therefore, it was recognized that the shape of the film lid portion 12 after a predetermined time has elapsed after the production of the containerized food X can be determined based on the curve of the above equation 1.

In addition, for each of the verification containers prepared in the same manner as the above verification container, except that the composition of the inert gas 14 was changed to a mixture of carbon dioxide gas and nitrogen gas = 80:20 (P = 80) or a mixture of carbon dioxide gas and nitrogen gas = 70:30 (P = 70), a graph of the actual measured values and theoretical values was plotted in the same manner as above, and the results are shown in Figure 9 (Examples 2-2 and 2-3).

In the results of Examples 2-2 and 2-3, the curve shapes of the actual measured values (dashed line) and the theoretical values (solid line) were also very similar. In these cases, the degree of agreement between the curves of the actual measured values and the theoretical values was calculated based on the above formula 2. As a result, the degree of agreement of the above curves was calculated to be 86.9% when P = 80 and 95.0% when P = 70. Therefore, it was recognized that the shape of the film lid portion 12 after a predetermined time has elapsed after the production of the containerized food X can be specified based on the curve of the above formula 1, even when the composition of the inert gas 14 is changed in various ways.

Therefore, if the surface of the target food 1 in vertical cross section can be formed into a concave shape with a desired gap to conform to the planned shape of the film lid portion 12 calculated based on the curve of equation 1, it is possible to prevent the target food 1 and the film lid portion 12 from coming into contact with each other after the specified time has elapsed.

Example 3
In Example 2, a plastic cup having a circular shape when viewed from above was used for verification, whereas in this example, a plastic cup having a rectangular shape when viewed from above (LRX121×84-165W, width 102 mm, length 66 mm, depth 8 mm: manufactured by Toyo Seikan Co., Ltd.) was used for verification similar to that of Example 2.

Specifically, the top surface of the film lid portion 12 was scanned for the horizontal width, and the vertical (depth) position x and horizontal position y were recorded. Similarly, the vertical (depth) position x and horizontal position y were recorded for the vertical width. Also, as in Example 2, the values obtained by calculating Equation 1 above were taken as theoretical values, and the horizontal theoretical values and vertical theoretical values were each plotted as solid lines in Figure 10.

As a result, the curve shapes of the actual measured values and the theoretical values were very similar for both the width and the height (actual measured values are not shown). The degree of agreement between these curves was calculated based on the above formula 2. As a result, the degree of agreement between the above curves was calculated to be 88% for the width and 92% for the height. Therefore, even in the case of a rectangular plastic cup, it was recognized that the shape of the film lid portion 12 after a predetermined time has elapsed after the production of containerized food X can be determined based on the curve of the above formula 1.

The present invention can be used for a containerized food having a target food filled in a storage container and a film lid that seals the opening of the storage container, and for a method for manufacturing the containerized food.

X Containerized food 1 Target food 10 Storage container 12 Film lid 13 Head space 14 Inert gas 15 Flange 01 Filling step 02 Surface treatment step 03 Gas replacement step 04 Sealing step

Claims (8)

A target food having a viscous consistency and filled in a storage container so that its vertical cross section is concave;
A film lid portion that seals the opening of the storage container,
The head space in the container is filled with an inert gas,
A containerized food product , wherein the depression in the surface shape of the target food product in a vertical cross section is defined based on the curve of the following equation 1 :
[Number 1]

The containerized food according to claim 1, wherein the target food has a deepest recess in the center of the container when viewed from above. The containerized food according to claim 1 or 2, wherein the depression in the surface shape of the target food in a vertical cross-sectional view is arc-shaped. 4. The container-packed food according to claim 1, wherein the container is a resin container formed in a tapered shape that decreases in diameter toward the bottom in a vertical cross-sectional view. 5. The container-packed food according to claim 1 , wherein the film lid is made of a resin or is a laminated film having a resin layer. The containerized food according to any one of claims 1 to 5 , wherein the inert gas contains at least one of carbon dioxide gas and nitrogen gas. A filling step of filling a viscous target food into a storage container;
A surface treatment step of shaping the target food so that the vertical cross section is concave;
a gas replacement step of spraying an inert gas into the storage container to replace the gas in the storage container with the inert gas;
A sealing step of sealing the opening of the container containing the target food with a film lid portion ,
A method for producing a containerized food , comprising molding the target food so that the concave shape in a vertical cross-sectional view is an arc shape defined based on the curve of the following mathematical expression 1 .
[Number 1]

The method for producing a containerized food according to claim 7 , wherein the target food is shaped using a pestle in the surface treatment step.

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