JPH0574A - Method for storing food, container used therefor, and method for manufacturing container - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a storage method capable of easily suppressing the growth of lactic acid bacteria and extending the storage period, a container used for the same, and a method for manufacturing the container. [Structure] A method of filling and sealing food in a container in which chitosan is applied to at least a part or all of the inner surface in contact with the contents. The manufacturing method for imparting chitosan is a coextrusion method, a coextrusion coating method, an extrusion method, or an extrusion coating method, and one of the outermost layers has a resin layer in which chitosan is kneaded and is extruded and cooled from a T-die. A film or sheet is formed by a method in which chitosan is previously sprayed and held on the surface while being cooled, and a pouch or a container is manufactured using the chitosan-provided laminate, film or sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for storing packable foods, a container used therefor, and a method for manufacturing the container.

[0002]

2. Description of the Related Art Methods for preventing spoilage of foods by microorganisms include sterilization by heating, inhibition of growth of microorganisms by removing oxygen by a deoxidizer or gas displacement packaging, addition of a preservative and the like. When sterilization is performed by heating, there are some foods that cannot be sterilized by heating because the quality of the product is deteriorated, such as deterioration in taste and browning. When oxygen is removed, the growth of aerobic bacteria that require oxygen can be inhibited, but the growth of anaerobic bacteria cannot be inhibited.

In addition, preservatives are not universal, and some bacteria are ineffective due to the preservatives. Lactic acid bacteria can grow at a low temperature of 5 ° C depending on the species, or at a relatively high temperature of 45 ° C.
Those that can grow even before and after are included, and there are those that can grow in about 10% sodium chloride or in a low acidic region of about pH 4.0. It is a facultative anaerobic bacterium that can grow with or without oxygen and is resistant to many antibacterial substances. Therefore, lactic acid bacteria pose a problem in food preservation.

[0004] Lactic acid bacteria are the cause of acidification of dairy products such as butter, ham, sausage, net of fish paste products, off-flavor, mayonnaise rot, dough consisting of flour, and rot of raw meat such as ground minced meat. It is considered a fungus.
Recent studies have revealed that the growth of these lactic acid bacteria can be inhibited by the addition of chitosan, and have been put to practical use.

Chitosan is a shell of crustaceans, insects, shells,
It is obtained by deacetylating chitin existing in fungi with concentrated alkali, and it is known that addition of about 10 ppm to food suppresses the growth of lactic acid bacteria.

[0006]

As described above, chitosan is obtained by deacetylating chitin existing in the crustacean shell, insects, shells, and fungi with concentrated alkali, and is highly safe. It is possible to suppress the growth of lactic acid bacteria by the addition amount of, and used in foods in which the growth of lactic acid bacteria poses a problem during storage.

However, a step of adding chitosan before filling and sealing is required, which makes the step complicated, such as controlling the addition amount. Moreover, even if it is a natural substance, chitosan,
Sometimes you want to avoid adding additives. Therefore, there has been a demand for a storage method capable of easily suppressing the growth of lactic acid bacteria and extending the storage period.

[0008]

In order to solve the above-mentioned problems, the present invention fills and seals food in a container or a packaging bag in which chitosan is added to at least a part or all of the inner surface in contact with the contents. A method for storing food and a container used for the method are provided.

Further, a method for manufacturing the above container is provided below. One of them is a co-extrusion method in which a plurality of thermoplastic resins are co-extruded, and a laminate in which at least the layer containing chitosan is laminated on the end side is used, and the layer containing chitosan in the laminate is There is a method for manufacturing a container by vacuum forming, pressure forming, vacuum pressure forming or heat sealing so that the inside of the container is formed. The other is a method of extruding a resin hot-melted by an extrusion coating method or an extruding method. Extruded from the die, until it is cooled by the cooling roll, the chitosan is sprayed on the extruded resin or on the cooling roll by the chitosan spraying means, and the resin film holding the chitosan on the resin surface after cooling by the cooling roll, A resin sheet, a laminated resin film, or a laminated resin sheet is used, and the surface having the chitosan of the resin film, the resin sheet or the laminated resin film, or the laminated resin sheet is inward. In so that, vacuum forming, pressure forming, a method for producing a container for producing containers by vacuum pressure forming or heat sealing.

[0010]

[Detailed Description] The problem was solved by adding chitosan to the surface of a container that comes into contact with food, and filling and sealing the food in this container. As a method of imparting chitosan to the food-contacting surface of the container used in the present invention, a method of kneading chitosan simultaneously with melting in a thermoplastic resin to form a container-food-contacting surface, and a thermoplastic resin on a substrate Extrusion from T-die, coating with thermoplastic resin, cooling with a chill roll, spraying chitosan powder when forming a film, and adhering to the surface of thermoplastic resin, extruding thermoplastic resin from T-die to form a sheet At that time, there are a method of applying and applying chitosan powder when solidifying by cooling with a cooling roll, a method of dispersing chitosan in a binder resin dissolved in a solvent, removing the solvent after application, and applying chitosan. . Besides this,
It is also possible to disperse the resin in an ultraviolet curable resin, an electron beam curable resin or the like, and to apply these by curing these resins after coating. It is also possible to form a container by a blow molding method using a parison having a layer in which chitosan is kneaded inside by coextrusion.

As the thermoplastic resin usable in the present invention, polyethylene, polypropylene, vinyl chloride, vinylidene chloride, nylon, polyester and the like can be arbitrarily selected in consideration of processability and food suitability. The amount of chitosan to be kneaded into the thermoplastic resin is appropriately 1 to 50%, preferably 5 to 25%, in consideration of antibacterial property and suitability for packaging material.
Is good. The amount of chitosan applied to the surface of the heat-melted resin is appropriately 0.1 to 5 g / m ² in a container, preferably 1 to 2.5 g.
It is preferable to give it so that it becomes / m ² .

As the binder resin usable in the present invention, polyester resin, polyurethane resin, acrylic resin, nitrocellulose resin, acetylcellulose resin, acetate butyrate resin, vinyl resin, epoxy resin, etc. Therefore, it can be arbitrarily selected in consideration of compatibility with the base material.

The amount of chitosan dispersed in the binder resin dissolved in the solvent is 0.1 to 5 g when the solvent is removed.
/ M ² and is suitably impart so, preferably better to disperse so that 1～2.5G / m ^2.
From the viewpoint of antibacterial properties, the chitosan used in the present invention preferably has an average molecular weight of 10,000 to 100,000, and the degree of acetylation is preferably 95% or more.

As the food applicable to the present invention, any food can be applied regardless of solid or liquid so long as the growth of lactic acid bacteria poses a problem in storage.

[0015]

The present invention has a constitution in which chitosan is applied to the inner surface of the packaging container or the packaging bag, which eliminates the step of adding chitosan before filling and sealing the contents, thus complicating the addition amount and the like. Eliminates unnecessary steps.

Further, a plurality of thermoplastic resins are coextruded by the coextrusion method of the present invention, and a layered product in which at least a layer containing chitosan is laminated on the end side, or an extrusion co-
The resin melted by the Ting method or the extrusion method is extruded from the T-die, and chitosan is dispersed on the extruded resin or on the cooling roll by the chitosan sprinkling means until it is cooled by the cooling roll. Use a resin film, resin sheet or laminated resin film, laminated resin sheet that holds chitosan on the surface of the resin after cooling so that the surface of the resin film, resin sheet or laminated resin film, or chitosan of the laminated resin sheet is on the inside. In addition, by manufacturing a container or a packaging bag by vacuum forming, pressure forming, vacuum pressure forming, or heat sealing, it becomes possible to easily produce a packaging container and a packaging bag having chitosan applied to the inner surface.

[0017]

【Example】

(First Embodiment) A detailed description will be given with reference to the drawings. FIG. 4 is an example of producing a laminate to which chitosan is added by the coextrusion method. Polyethylene (PE, 55 µm) 5/10% chitosan kneaded polyethylene through an adhesive layer 3 applied by a well-known gravure coating method on a base material of K-coated nylon film (KNy, 15 µm) 2 by a coextrusion method. (Chitosan 10% kneaded PE, 5 μm) 4 was extruded from a co-extrusion T-die 13 and was passed through a nip roll 7, a first cooling roll 8 and a second cooling roll 9 to form a laminated body 10 as shown in FIG. As shown in the figure, a pouch 1 having a size of 5 cm × 8 cm (total surface area 80 cm ² ) in contact with food was prepared. FIG. 5 is a cross-sectional explanatory view of the laminated body 10. 2 is an AA cross-sectional explanatory view of the pouch of FIG.

2.0 × 10 ⁵ (pieces / m) for a plurality of pouches
l) 10 ml of Brix liquid medium inoculated with lactic acid bacteria
Each was filled and sealed. This was preserve | saved at 30 degreeC, it opened one by one with time, and the number of bacteria was measured by the pouring method using the Brix agar medium.

(Comparative Example 1) A film obtained by forming polyethylene (PE, 60 μm) on a base material of K-coated nylon film (KNy, 15 μm) by an extrusion coating method and having one side in contact with food of 5 cm × 8 cm ( A pouch with a total surface area of 80 cm ² ) was prepared. The procedure was the same as in Example 1, but the difference was that chitosan was not added, and the others were the same. A plurality of pouches was filled with 10 ml of Brix liquid medium in which the lactic acid bacterium used in Example 1 was inoculated and sealed. This was preserve | saved at 30 degreeC, it opened one by one with time, and the number of bacteria was measured by the pouring method using the Brix agar medium.
The results of these measurements are shown in Table 1.

[0020]

[Table 1]

(Example 2) As shown in FIG. 6, polyethylene (PE, 40 μm) 12 was formed on a substrate of K-coated stretched polypropylene film (KOPP, 20 μm) 11 through an adhesive layer 3 by an extrusion coating method. The formed film 16 was produced. At this time, the dusting machine 14 drops the chitosan 15 and the chitosan 15 is placed on the first cooling roll 8.
Was attached and the melted polyethylene 12 was cooled on the cooling surface to which the chitosan 15 was attached, whereby the chitosan 15 was provided on the surface of the polyethylene 12 as shown in FIG. 7. The applied amount of chitosan was 1 g / m ² . In this film, the polyethylene surface with the attached chitosan is the surface in contact with the content, and the one surface in contact with the content is 10 cm x 10
cm (total surface area 200 cm ² ) was prepared. Five commercially available wiener sausages (total weight: 87.5 g) labeled with the addition of sorbic acid as a preservative were vacuum packed in this pouch and stored at 20 ° C. A plurality of this package was prepared and sequentially opened to observe the occurrence of net.

(Comparative Example 2) A K-coated stretched polypropylene film (KOPP,
Polyethylene (PE, 40μ) on a substrate of 20μm
In the film formed with m), one side contacting food is 10
A pouch of cm × 10 cm (total surface area 200 cm ² ) was prepared. The wiener sausage used in Example 2 was vacuum packed in this pouch and stored at 20 ° C. A plurality of this package was prepared and sequentially opened to observe the occurrence of net. The results are shown in Table 2.

[0023]

[Table 2]

(Embodiment 3) In the apparatus shown in FIG. 8, polypropylene (PP) 17 melted by heat is extruded from the T die 13 so that the final thickness becomes 1.5 mm, and the first cooling roll 8 and the nip roll 7 are formed. Before being solidified to form a sheet by being cooled with P., P is heat-melted with a powder duster 14 between the T die 13 and the first cooling roll 8 and the nip roll 7.
Chitosan 15 was sprinkled on P17, cooled by the first cooling roll 8 and the second cooling roll 9, and solidified, and chitosan 15 was applied onto the polypropylene sheet 17 as shown in FIG. Although the second cooling roll is used in the present embodiment, the number of cooling rolls may be appropriately selected.

The amount of chitosan applied at this time was 3 g / m ² . Using this sheet, a cup-shaped container having an internal volume of 220 ml as shown in FIG. 3 was prepared by a vacuum forming method so that the surface to which chitosan was applied was the surface in contact with food. This cup has 5.2 × in a sterile chamber at 30 ° C.
200 ml of Brix liquid medium inoculated with 10 ⁵ (cells / ml) of lactic acid bacteria was filled and stored, and the number of bacteria was measured over time by the pour-in method using Brix agar medium.

(Comparative Example 3) From a PP sheet having a thickness of 1.5 mm, an internal volume of 22 was obtained by a vacuum forming method as in Example 3.
A 0 ml cup-shaped container was prepared. 30 ° in this cup
In a sterile chamber of C, 200 ml of Brix liquid medium inoculated with 5.2 × 10 ⁵ (cells / ml) of lactic acid bacteria was filled and stored, and the number of bacteria was determined by the pour method using Brix agar medium over time. It was measured. The results are shown in Table 3.

[0027]

[Table 3]

(Embodiment 4) A vinyl resin paint mixed with chitosan at a ratio of 1.5% (W / W) was applied to the body of a tin-made three-piece can (dobu-zuke) and the solvent was applied. After the removal, the bottom material was applied by winding to make a can of 250 ml, filled with sake, and the lid material was applied by winding and sealed.

(Comparative Example 4) The same sake as that used in Example 4 was filled in a three-piece can made by a conventional method and sealed. No application of chitosan. When these were stored at 30 ° C. for 10 days, opened, and checked for properties, Comparative Example 4 was cloudy and had a burning odor, whereas Example 4 was not cloudy and the taste was the same as before storage. There wasn't.

[0030]

EFFECTS OF THE INVENTION As shown in the above examples, it is possible to extend the storage period of foods in which the growth of lactic acid bacteria poses a problem in storage, just by packaging. In the sausages shown in Example 2 and Comparative Example 2, although sorbic acid as a preservative was added, sorbic acid alone could not inhibit the growth of lactic acid bacteria. The effect of chitosan inhibits the growth of lactic acid bacteria,
This is an example where the preservation period can be extended. The method of applying chitosan in any of Examples 1, 2, 3, and 4 shows the preservation effect, and the container used in the present invention can be produced by any of the applying methods. there were.

Further, the storage method according to the present invention is very economical because the object can be achieved only by packaging, and there is no need to change the conventional manufacturing process.

[0032]

[Brief description of drawings]

FIG. 1 is a perspective view of a pouch showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing a pouch according to an embodiment of the present invention.

FIG. 3 is an explanatory cross-sectional view of a container manufactured by vacuum forming showing an embodiment of the present invention.

FIG. 4 is a schematic explanatory view illustrating a step of forming a chitosan-kneaded laminated film on a base material via an adhesive by a coextrusion method.

5 is a cross-sectional explanatory view of the laminated body 10 manufactured according to FIG.

FIG. 6 is a schematic explanatory view illustrating a step of applying chitosan by an extrusion coating method.

FIG. 7 is an explanatory cross-sectional view of the laminated film manufactured according to FIG.

FIG. 8 is a schematic explanatory view illustrating a step of extruding a resin melted from a T-die and applying chitosan.

FIG. 9 is a cross-sectional explanatory view of the chitosan-added film manufactured according to FIG. 1. Pouch 2 ... K-coated nylon film 3 ... Adhesive layer 4 ... Chitosan-blended polyethylene 5 ... Polyethylene 6 ... Chitosan-added layer 7 ... Nip roll 8 ... 1st cooling roll 9 ... 2nd cooling roll 10 ... Laminate 11 ... K coat stretched polypropylene film 12 ... Molten polyethylene 13 ... T die 14 ... Powder shaving machine 15 ... Chitosan 16 ... Chitosan provision film 17 ... Molten polypropylene

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 27/18 F 6122-4F B65D 25/14 Z 6540-3E 81/24 Z 7191-3E // B29C 51/10 7722-4F 51/14 7722-4F B29L 9:00 4F 22:00 4F (72) Inventor Shoya Sugawara 1-5-1 Taito, Taito-ku, Tokyo Tokyo Toppan Printing Co., Ltd.

Claims (4)

[Claims] 1. A method for preserving food, characterized in that at least a part or all of the inner surface in contact with the contents is filled with a food product and sealed in a container formed with chitosan. 2. A container formed by applying chitosan to at least a part or all of the inner surface in contact with the contents. 3. A laminate in which a plurality of thermoplastic resins are coextruded by a coextrusion method so that at least the layer containing chitosan is on the end side, and the layer containing chitosan in the laminate is A method of manufacturing a container, characterized in that the container is manufactured by vacuum forming, pressure forming, vacuum pressure forming or heat sealing so as to be inside. 4. A resin hot-melted by an extrusion coating method or an extrusion method is extruded from a T-die and is cooled by a chill roll until the resin is extruded or a chill roll is dispersed by chitosan. Chitosan of resin film, resin sheet or laminated resin film, laminated resin sheet, using resin film, resin sheet or laminated resin film, laminated resin sheet which has chitosan dispersed on the surface of resin after cooling with chitosan A method for producing a container, characterized in that the container is produced by vacuum forming, pressure forming, vacuum pressure forming, or heat sealing so that the surface having the above is on the inside.