JP3063236B2 - Food preservation method, container used therefor, and method of manufacturing container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preserving wrappable food, a container used therefor, and a method for producing the container.

[0002]

2. Description of the Related Art Methods for preventing deterioration of foods by microorganisms include sterilization by heating, inhibition of growth of microorganisms by removing oxygen using a deoxidizer or gas replacement packaging, addition of a preservative, and the like. When sterilization by heating is performed, the quality of the food, such as a decrease in taste and browning, is reduced. Therefore, there are foods that cannot be sterilized by heating. When oxygen is removed, the growth of aerobic bacteria requiring oxygen can be inhibited, but the growth of anaerobic bacteria cannot be inhibited.

[0003] Further, the preservative is not versatile, and there are bacteria that are ineffective due to the preservative. Lactic acid bacteria can be grown at a low temperature of 5 ° C depending on the species, or at a relatively high temperature of 45 ° C.
Some include those that can grow even before and after, and some that can grow in about 10% saline or in a low-acid 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. For this reason, lactic acid bacteria have become a problem in food preservation.

[0004] Lactic acid bacteria cause acid rancidness of dairy products such as butter, ham, sausage, fish meat kneaded products, generation of off-flavors, rot of mayonnaise, rot of flour dough, rot of raw meat such as minced meat and the like. 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 they have been put to practical use.

[0005] Chitosan is a crustacean crust, insect, shell,
It is obtained by deacetylating chitin present in fungi with concentrated alkali, and is known to suppress the growth of lactic acid bacteria by adding about 10 ppm to food.

[0006]

As described above, chitosan is obtained by deacetylating chitin present in shells of shellfish, insects, shells, and fungi with concentrated alkali, and has high safety. It is possible to suppress the growth of lactic acid bacteria with the addition amount of lactic acid bacteria, and it is used for foods in which the growth of lactic acid bacteria becomes a problem during storage.

[0007] However, a step of adding chitosan is required before filling and sealing, which complicates the steps such as controlling the addition amount. Also, even with chitosan, which is a natural substance,
Sometimes it is desirable to avoid the addition of additives. Therefore, a storage method that can easily suppress the growth of lactic acid bacteria and extend the storage period has been desired.

[0008]

In order to solve the above-mentioned problems, the present invention provides at least an inner surface which is in contact with the contents ,
Chitosan having a molecular weight of 10,000 to 100,000
5-25% kneaded resin layer or molten resin table
A resin layer having 1 to 2.5 g / m ² attached was arranged on the surface side .
A container made of a laminated material, and filling the container with food,
This is a method for preserving food, characterized by sealing.

In the following, the method for producing the container is as follows .
A laminated material provided with a resin layer having chitosan on its inner surface co-extrudes a plurality of thermoplastic resins by a co-extrusion method, and has an average molecular weight of at least 10,000 to 100,000.
Layer of chitosan kneaded with 5 to 25%
Fusion was on the surface side of the resin 1~2.5g / m ² spraying, deposition of
By using a laminated body laminated so that the resin layer is placed on the end side, so that the layer containing chitosan of the laminated body is on the inside,
A container manufacturing method characterized by manufacturing a container by vacuum forming, pressure forming, vacuum pressure forming or heat sealing. Another manufacturing method is to extrude a resin melted by an extrusion coating method or an extrusion method from a T-die, and until the resin is cooled by a cooling roll, and the average molecular weight on the extruded resin or the cooling roll is reduced. 10,000-10
A resin layer in which 5 to 25% of 000 chitosan is kneaded,
Alternatively , after spraying and adhering 1 to 2.5 g / m ² on the surface side, and cooling with a cooling roll, a laminated film in which the resin film holding chitosan on the resin surface is on the inner surface side,
Pneumatic molding, pressure molding, vacuum pressure molding or heat sealing
Container manufacturing method, characterized by manufacturing a container.
You.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a container surface in contact with food.
Chitosan and fill the container with food
Container that can store food for a long time by sealing, and
Long-term preservation of food has become possible. The container of the present invention , and
As a method of imparting chitosan to the surface of the container used for the preservation method, which is in contact with the food, a method of kneading the chitosan simultaneously with the melting of the thermoplastic resin and forming the surface of the container in contact with the food, the method of forming the thermoplastic resin on the base material to process extruded from a T-die, the thermoplastic resin is coated, and cooled by the cooling roll,
Spraying chitosan powder when forming a film and attaching it to the thermoplastic resin surface, or cooling with a cooling roll and solidifying when spraying and applying the chitosan powder
There is a method. Further , it is also possible to form a container by a blow molding method using a parison having a layer into which chitosan is kneaded 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, food suitability and the like. The amount of chitosan to be kneaded into the thermoplastic resin is suitably 1 to 50%, preferably 5 to 25%, in consideration of antibacterial properties and suitability for a packaging material.
Is good. The amount of chitosan applied to the hot-melt resin surface is suitably 0.1 to 5 g / m ² when the container is used, and preferably 1 to 2.5 g.
/ M ² .

[0012]

The chitosan used in the present invention has an average molecular weight of 10,000 to 100,000 in consideration of antibacterial properties.
It is preferably 0, and the acetylation is preferably 95% or more.

The food applicable to the present invention may be any solid or liquid food as long as the growth of lactic acid bacteria poses a storage problem.

[0015]

According to the present invention, the structure in which chitosan is applied to the inner surface of a packaging container or a packaging bag eliminates the need for a step of adding chitosan before filling and sealing the contents, and complicates the control of the amount of addition. Unnecessary steps are also unnecessary.

A laminate or an extruded core obtained by co-extruding a plurality of thermoplastic resins by the co-extrusion method of the present invention so that at least a layer containing chitosan is on the end side.
Extrusion of chitosan onto the extruded resin or on the cooling roll by means of chitosan spraying means until the hot-melted resin is extruded from the T-die through a T-die and cooled by a cooling roll by a cooling method or an extrusion method. After cooling, using a resin film, a resin sheet or a laminated resin film, or a laminated resin sheet holding chitosan on the resin surface, the surface of the resin film, the resin sheet or the laminated resin film, the laminated resin sheet having the chitosan is inside. In addition, by manufacturing a container or a packaging bag by vacuum forming, pressure forming, vacuum pressure forming or heat sealing, it is possible to easily manufacture a packaging container and a packaging bag having chitosan applied to the inner surface.

[0017]

【Example】

(Example 1) This will be described in detail with reference to the drawings. FIG. 4 shows an example of manufacturing a laminate to which chitosan is applied by a co-extrusion method. Polyethylene (PE, 55 μm) 5 / Chitosan 10% kneaded polyethylene through an adhesive layer 3 applied by a well-known gravure coating method on a substrate of a K-coated nylon film (KNy, 15 μm) 2 by co-extrusion. (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, as shown in FIG. As shown, 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 an explanatory sectional view of the laminate 10. FIG. 2 is a sectional view of the pouch shown in FIG.

2.0 × 10 ⁵ (pieces / m 2)
l) 10 ml of Brix liquid medium inoculated with lactic acid bacteria
Each was filled and sealed. This was stored at 30 ° C., opened sequentially with time, and the number of bacteria was measured by a pour method using a Brix agar medium.

(Comparative Example 1) A film in which polyethylene (PE, 60 μm) was formed on a K-coated nylon film (KNy, 15 μm) substrate by extrusion coating method, and one side in contact with food was 5 cm × 8 cm ( A pouch having a total surface area of 80 cm ² ) was prepared. The procedure was performed in the same manner as in Example 1, except that chitosan was not added. A plurality of pouches were filled with 10 ml of a Brix liquid medium inoculated with the lactic acid bacteria used in Example 1, and sealed. This was stored at 30 ° C., opened sequentially with time, and the number of bacteria was measured by a pour method using a Brix agar medium.
Table 1 shows the results of these measurements.

[0020]

[Table 1]

Example 2 As shown in FIG. 6, a polyethylene (PE, 40 μm) 12 was coated on a base material of a K-coated stretched polypropylene film (KOPP, 20 μm) 11 via an adhesive layer 3 by an extrusion coating method. The formed film 16 was produced. At this time, the chitosan 15 is dropped by the dusting machine 14 and is placed on the first cooling roll 8.
By cooling the melted polyethylene 12 on the cooling surface to which the chitosan 15 was attached, the chitosan 15 was provided on the surface of the polyethylene 12 as shown in FIG. The applied amount of chitosan was 1 g / m ² . In this film, the polyethylene surface to which chitosan was attached was the surface in contact with the contents, and one surface in contact with the contents was 10 cm × 10
cm (total surface area: 200 cm ² ). To this, five commercially available wiener sausages (total weight: 87.5 g) with an indication of addition of sorbic acid as a preservative were vacuum-packaged in this pouch and stored at 20 ° C. A plurality of the packages were prepared and opened sequentially with time, and the occurrence of nets was observed.

Comparative Example 2 A K-coated stretched polypropylene film (KOPP,
20μm) on a polyethylene (PE, 40μ)
m), one side in contact with 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-packaged in this pouch and stored at 20 ° C. A plurality of the packages were prepared and opened sequentially with time, and the occurrence of nets was observed. Table 2 shows the results.

[0023]

[Table 2]

(Embodiment 3) In the apparatus shown in FIG. 8, a polypropylene (PP) 17 which has been hot-melted is extruded from a T-die 13 so as to have a final thickness of 1.5 mm. Before being cooled and solidified to form a sheet, the P melted by the powdering machine 14 between the T-die 13 and the first cooling roll 8 and the nip roll 7.
P17 was sprinkled with chitosan 15, cooled with the first cooling roll 8 and the second cooling roll 9 and solidified, and the chitosan 15 was applied on the polypropylene sheet 17 as shown in FIG. In this embodiment, the second cooling roll is used, but 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 inner volume of 220 ml as shown in FIG. 3 was produced by a vacuum forming method so that the surface provided with chitosan was in contact with the food. This cup was placed in a sterile chamber at 30 ° C. in 5.2 ×
200 ml of a Brix liquid medium inoculated with 10 ⁵ (cells / ml) lactic acid bacteria was filled and stored, and the number of cells was measured over time by a pour method using a Brix agar medium.

(Comparative Example 3) From the PP sheet having a thickness of 1.5 mm, the inner volume was 22
A 0 ml cup-shaped container was prepared. 30 ° in this cup
200 ml of a Brix liquid medium inoculated with 5.2 × 10 ⁵ (cells / ml) of lactic acid bacteria in the sterile chamber C, stored, and counted over time by a pour method using a Brix agar medium. It was measured. Table 3 shows the results.

[0027]

[Table 3]

[0028]

[0029]

[0030]

As described in the above examples, it is possible to extend the preservation period of a food product in which the growth of lactic acid bacteria is a problem in preserving it simply by packaging. Although the sausages shown in Example 2 and Comparative Example 2 did not inhibit the growth of lactic acid bacteria by sorbic acid alone, despite the addition of sorbic acid as a preservative, use of the storage method according to the present invention. Therefore, the growth of lactic acid bacteria is inhibited by the action of chitosan,
This is an example in which the storage period can be extended. In any of the methods of Example 1, Example 2, Example 3, and Example 4, the preservation effect was exhibited, and the container used in the present invention can be produced by any of the methods. there were.

The preservation method according to the present invention can achieve its purpose only by packaging, so that there is no need to change the conventional manufacturing process, and it is very economical.

[0032]

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along the line AA in FIG. 1 of the pouch showing one embodiment of the present invention.

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

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

FIG. 5 is an explanatory sectional view of the laminated body 10 manufactured according to FIG. 4;

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

FIG. 7 is an explanatory sectional view of the laminated film manufactured according to FIG. 6;

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

9 is a cross-sectional explanatory view of the chitosan-provided film produced according to FIG. 8 1. Pouch 2. K-coated nylon film 3. Adhesive layer 4. Chitosan-kneaded polyethylene 5. Polyethylene 6. Layer provided with chitosan 7. Nip roll 8 ... First cooling roll 9 ... Second cooling roll 10 ... Laminate 11 ... K coated stretched polypropylene film 12 ... Molten polyethylene 13 ... T die 14 ... Flouring machine 15 ... Chitosan 16 ... Chitosan applied film 17 ... Molten polypropylene

────────────────────────────────────────────────── (5) References JP-A-62-83875 (JP, A) JP-A-64-5837 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23L 3/3562 A23L 3/00 B29C 47/06

Claims (4)

(57) [Claims] At least an inner surface in contact with the contents has an average
Chitosan with a size of 10,000 to 100,000
~ 25% kneaded resin layer or molten resin surface
Product with a resin layer attached to the side of 1 to 2.5 g / m ²
A food preservation method, characterized by filling and sealing a food in a container made of a layer material . 2. The method according to claim 1, wherein at least an inner surface in contact with the contents has an average
Chitosan with a size of 10,000 to 100,000
~ 25% kneaded resin layer or molten resin surface
Product with a resin layer attached to the side of 1 to 2.5 g / m ²
Container made of layer material . 3. The laminate material is co-extruded with a plurality of thermoplastic resins by a co-extrusion method to obtain at least an average molecular weight.
But 10,000 to 100,000 chitosan, 5-2
5% kneaded resin layer or molten resin surface side
Vacuum forming, pressure forming, vacuum forming using a laminated body in which the layer containing chitosan of the laminated body is on the inner side using a laminated body in which the resin layer adhered to 1 to 2.5 g / m ² is on the end side. The method for producing a container according to claim 2, wherein the container is produced by air pressure molding or heat sealing. 4. A resin having a mean molecular weight of 10,000 on the extruded resin or on the cooling roll before the resin melted by the extrusion coating method or extrusion method is extruded from a T-die and cooled by a cooling roll. ~ 100,000 keys
A resin layer in which 5-25% of Tosan is kneaded on the surface side, or
After spraying and adhering 1 to 2.5 g / m ² and cooling with a cooling roll, the resin film holding chitosan on the resin surface has an inner surface
Vacuum forming and pressurizing the laminated film on the side
The container can be manufactured by molding, vacuum pressure molding or heat sealing.
The method for producing a container according to claim 2, characterized in that: