JP3077291B2 - Food preservation method and container used for it - 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 of preserving wrappable food and a container used therefor.

[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] Chitosan is a crustacean crust, insect, shell,
It is obtained by deacetylating chitin present in fungi with concentrated alkali, has the effect of inhibiting the growth of lactic acid bacteria, and is added to food or applied at least partially or entirely to the inner surface in contact with the contents of the container It has been used.

[0004] Lactic acid bacteria include those that can grow at a low temperature range of 5 ° C and those that can grow at a relatively high temperature of around 45 ° C, depending on the species.
Some are capable of growing in a moderately low acid region. 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. Lactic acid bacteria are considered as causative bacteria of rancidity of dairy products such as butter, ham, sausage, fish meat kneading products, generation of off-flavor, rot of mayonnaise, rot of dough composed of flour, rot of raw meat such as packaged minced meat, etc. Have been.

[0005] Chitosan is an excellent substance that inhibits the growth of such lactic acid bacteria, but has no effect on microorganisms other than lactic acid bacteria, or is extremely weak.

[0006] The silver-substituted zeolite is a zeolite (Zeolit).
e, zeolite) in which silver ions are replaced by silver ions, and silver-substituted zeolite is kneaded into the inner resin layer of a packaging container in contact with food, and silver-substituted zeolite particles are formed on the inner resin layer surface of the packaging container. Has been already used as a preservation packaging container having an antibacterial effect on foods. In addition to silver zeolite, those in which montmorillonite or zinc phosphate retains silver ions are also used.

Further, a packaging container having a silver layer provided on the inner surface of a packaging container in contact with foods by a PVD method such as a vacuum deposition method, a sputtering method, or an ion plating method is a preservation package having an antibacterial effect for foods. Practical as containers. In this case, silver is generally vapor-deposited on the surface of the resin layer on the inner surface of the packaging container in contact with foods.

The antibacterial effect of silver has been known for a long time, and it is thought that silver ionizes and elutes into the water of foods, and the eluted silver ions are taken into the body of microorganisms to act. . That is, putting silver foil in foods, storing foods in silver containers, silver has been used for tableware and dentures for a long time, and has extremely high antibacterial effect and safety. . In addition to copper, copper and iron have antibacterial effects, but they have not been put to practical use for foods due to safety issues. Although the antibacterial property of this silver has a very broad antibacterial spectrum, it is clear that the antibacterial property against lactic acid bacteria is weak.

[0009]

As described above, chitosan is obtained by deacetylating chitin present in shells of shellfish, insects, shells, and fungi with concentrated alkali, and is highly safe. A container in which chitosan is provided on the surface in contact with food can be suppressed by the addition amount of lactic acid bacteria, and is used for food in which the growth of lactic acid bacteria poses a problem during storage. Further, as described above, containers utilizing the antibacterial property of silver are highly safe and have an antibacterial effect on many microorganisms except lactic acid bacteria, so that they are widely used.

[0010] However foods comprising lactic acid bacteria and other microorganisms and is stored on a problem, for example, foods such as pickles, if chitosan was packaging in containers imparted to the surface in contact with the food, by lactic acid bacteria, the production of acid Although it could be prevented, the generation of carbon dioxide by the yeast could not be prevented, the container swelled, and the preservation effect could not be obtained. On the other hand, when packaging is performed in a container provided with silver, generation of gas can be prevented, but generation of acid cannot be prevented, and a phenomenon that the acidity becomes strong during storage has occurred. Therefore, the growth of lactic acid bacteria and other microorganisms can be easily and simultaneously suppressed,
There has been a demand for a preservation method capable of extending the preservation period.

[0011]

In order to solve the above-mentioned problems, the present invention provides chitosan on at least a part or all of an inner surface in contact with a content and at least a part or all of an inner surface in contact with the content. It is intended to provide a method for storing food, in which food or food is filled and sealed in a container or packaging bag provided with silver, and a container used for the method.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The problem was solved by providing chitosan and silver on the surface of a container in contact with food, and filling and sealing the container with the food.

As a method for providing chitosan and silver on the surface of the container used in the present invention, which is in contact with food, powdered chitosan and a carrier provided with silver ions are simultaneously kneaded into a resin, and the container is brought into contact with the food. A container member on which a resin layer may be formed or chitosan is provided on a surface in contact with food by a known method, and a container on which silver is provided on a surface in contact with food by a known method The container used in the present invention may be combined with the member.

The method of applying chitosan to the food contact surface of the container used in the present invention includes a method in which chitosan is kneaded simultaneously with melting into a thermoplastic resin to form a surface in contact with the food of the container, and a method based on the thermoplastic resin. Extruded from the T-die on the material,
A method in which a thermoplastic resin is coated and cooled by a cooling roll to form a film by spraying chitosan powder to adhere to the surface of the thermoplastic resin. A method of applying and applying chitosan powder when cooling and solidifying, a method of dispersing chitosan in a binder resin dissolved in a solvent, removing the solvent after application, and applying chitosan. In addition, dispersed in ultraviolet curable resin, electron beam curable resin, etc.,
It is also possible to apply these resins by curing these resins after application. 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.

Further, a silver zeolite-like material carrying silver ions can be applied in the same manner. In addition, a method of applying silver to a surface of resin, metal such as aluminum steel, glass, paper, or the like by a PVD method such as a vacuum evaporation method, a sputtering method, or an ion plating method may be used.

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 kneading amount of the carrier supporting chitosan and silver ions when kneading into the thermoplastic resin is 1 to 50 in total in consideration of antibacterial properties and suitability of the packaging material.
% Is appropriate, and preferably 5 to 25% by weight.

The amount of the carrier that supports chitosan and silver ions on the surface of the hot-melted resin is such that the total amount is 0.1 to 5 g / m ² when used as a container. Is suitable, preferably the total amount is 1 to 2.5 g
/ M ² .

The binder resin usable in the present invention includes polyester resin, polyurethane resin, acrylic resin, nitrocellulose resin, acetylcellulose resin, acetate butyrate resin, vinyl resin, epoxy resin and the like. Can be arbitrarily selected in consideration of suitability with the base material and the like.

The amount of the carrier supporting chitosan and silver ions dispersed in the binder resin dissolved in the solvent is as follows:
It is appropriate that the total amount is 0.1 to 5 g / m ² when the solvent is removed, and preferably the total amount is 1 to 5 g / m ^2.
To 2.5 g / m ² .

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 degree of acetylation is preferably 95% or more.

The silver zeolite usable in the present invention preferably has a silver substitution ratio of 5 to 70%. When a silver layer is formed on the interface of a container in contact with food by the PVD method, only the silver layer surface is involved in antibacterial properties. Therefore, it is preferable that the silver layer be as thin as possible from the viewpoint of economy.

The amount of chitosan and silver to be applied and the ratio thereof can be set according to the number of microorganisms in the food to which the present invention is applied, nutrients available for microorganisms, storage conditions, and the like. As a food applicable to the present invention, any food, in which the growth of lactic acid bacteria and other microorganisms poses a storage problem, can be applied regardless of whether it is solid or liquid.

[0023]

According to the present invention, a food in which the growth of lactic acid bacteria and other microorganisms poses a storage problem can be economically stored by providing chitosan and silver on the surface of the container in contact with the food.

[0024]

【Example】

(Example 1) This will be described in detail with reference to the drawings. FIG. 4 shows an embodiment for producing a laminate provided with chitosan and silver by a coextrusion method.

By coextrusion, a polyethylene (PE, 55 μm) 5 / chitosan 10% is coated on a substrate of a K-coated nylon film (KNy, 15 μm) 2 through an adhesive layer 3 applied by a well-known gravure coating method. Polyethylene kneaded with 10% of silver zeolite (silver substitution rate 40%) (PE mixed with 10% of chitosan and 10% of silver zeolite, 5 μm) 4
Is extruded from a co-extrusion T-die 13, and nip rolls 7,
Using the laminate 10 formed between the first cooling roll 8 and the second cooling roll 9, a pouch 1 having one side in contact with food, 5 cm × 8 cm (total surface area 80 cm ² ), as shown in FIG. 1, was produced. . 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)
10 ml of the Brix liquid medium inoculated with the lactic acid bacterium of 1)
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. In addition, 5.5 × 10 ⁵
(Pieces / ml) were filled with 10 ml of glucose peptone liquid medium inoculated with baker's yeast and sealed. 30 ℃
, And sequentially opened, and the number of bacteria was measured by a pour method using a potato dextrose agar medium.

(Comparative Example 1) On a base material of a K-coated nylon film (KNy, 15 μm) 2 by a co-extrusion method,
Polyethylene (PE, 55 μm) 5 / Chitosan 10% kneaded polyethylene (Chitosan 10% kneaded PE, 5μ) via the adhesive layer 3 applied by a well-known gravure coating method
m) 4 is extruded from a co-extrusion T-die 13 and a single side in contact with food as shown in FIG. 1 using a laminate 10 formed between a nip roll 7, a first cooling roll 8, and a second cooling roll 9. Is 5cm x 8cm (total surface area 80c
m ² ) was prepared. FIG. 5 is an explanatory sectional view of the laminate 10. FIG. 2 is an explanatory cross-sectional view of the pouch of FIG. 1 taken along the line AA ′.

The 2.0 × used in Example 1 was used for a plurality of pouches.
Each 10 ml of Brix liquid medium inoculated with 10 ⁵ (cells / ml) lactic acid bacteria 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.

Also, a plurality of pouches were filled with 10 ml of a liquid medium containing butter sugar peptone inoculated with 5.5 × 10 ⁵ (cells / ml) of baker's yeast 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 potato dextrose agar medium.

(Comparative Example 2) A K-coated nylon film (KNy, 15 μm) 2 was coated on a base material by co-extrusion.
Polyethylene (PE, 55 μm) 5 / silver zeolite 10 via an adhesive layer 3 applied by a well-known gravure coating method
% (Silver substitution rate 40%) kneaded polyethylene (silver zeolite 10% kneaded PE, 5 μm) 4 co-extrusion T die 1
3, using a laminated body 10 formed between the nip roll 7, the first cooling roll 8, and the second cooling roll 9, as shown in FIG.
cm (total surface area: 80 cm ² ). FIG. 5 is an explanatory sectional view of the laminate 10. FIG. 2 shows FIG.
It is AA sectional explanatory drawing of this pouch.

The 2.0 × used in Example 1 was used for a plurality of pouches.
Each 10 ml of Brix liquid medium inoculated with 10 ⁵ (cells / ml) lactic acid bacteria 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.

In addition, a plurality of pouches were filled with 10 ml of a glucose peptone liquid medium inoculated with 5.5 × 10 ⁵ (cells / ml) of baker's yeast 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 potato dextrose agar medium.

(Comparative Example 3) A film in which polyethylene (PE, 60 μm) was formed on a K-coated nylon film (KNy, 15 μm) base material 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. A plurality of pouches were filled with 10 ml of the Brix liquid medium inoculated with 2.0 × 10 ⁵ (cells / ml) lactic acid bacteria used in Example 1 and sealed. This is stored at 30 ° C. and opened sequentially with time.
The number of bacteria was measured by a pour method using a Brix agar medium.

A plurality of pouches were filled with 10 ml of a glucose peptone liquid medium inoculated with 5.5 × 10 ⁵ (cells / ml) of baker's yeast 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 potato dextrose agar medium. Table 1 shows the results of these measurements.

[0035]

[Table 1]

Example 2 As shown in FIG. 6, a polyethylene (PE, 40 μm) 12 was coated on a substrate 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 . (Film A)

Similarly, a K-coated stretched polypropylene film (KOPP,
A film 16 was prepared in which polyethylene (PE, 40 μm) 12 was formed on a substrate (20 μm) 11 via an adhesive layer 3. At this time, a silver zeolite having a silver substitution rate of 20% is dropped by a dusting machine 14 to deposit silver zeolite on the first cooling roll 8, and the molten polyethylene 12 is cooled on a cooling surface to which the silver zeolite is attached. In the same manner, silver zeolite was provided on the surface of polyethylene 12. The amount of silver zeolite applied was 1 g / m ² . (Film B)

The film A and the film B were attached to each other, and as shown in FIG. 10, the polyethylene surface to which chitosan and silver zeolite were attached was a surface in contact with the contents.
One side in contact with the contents is 5cm x 8cm (total surface area 80c
m ² ) pouches were prepared.

The koji used for the hatchet pickling of radish was diluted 10-fold with sterilized distilled water, and filtered with sterilized gauze to remove solid substances to obtain an extract. This liquid was added to the pouch in an amount of 10 ml. Filled and sealed. A plurality of the pouches were prepared, stored at 30 ° C., opened sequentially with time, and the number of bacteria was measured by a pour method using a potato dextrose agar medium and a Brix agar medium.

(Comparative Example 4) By extrusion coating method
R, K-coated stretched polypropylene film (KOPP,
20μm) on a polyethylene (PE, 40μ)
m) and the food (film C)
5cm x 8cm (total surface area 40cm) ^Two) And
And the other side is in contact with food with film A.
5cm x 8cm (total surface area 40cm)^TwoPow)
H was made.

Then, 10 ml of the extract used in Example 2 was added.
Filled and sealed. Prepare a plurality of these pouches,
, And sequentially opened, and the number of bacteria was measured by a pour method using a potato dextrose agar medium and a Brix agar medium.

(Comparative Example 5) In the film C, one side in contact with the food was 5 cm × 8 cm (total surface area 40 cm ² ), and the other side in the film B was 5 cm × 8 in contact with the food.
cm (total surface area: 40 cm ² ).

To this, 10 ml of the extract used in Example 2 was added.
Filled and sealed. Prepare a plurality of these pouches,
, And sequentially opened, and the number of bacteria was measured by a pour method using a potato dextrose agar medium and a Brix agar medium.

Comparative Example 6 A pouch having a size of 5 cm × 8 cm (total surface area: 80 cm ² ) on one side of the film C, which was in contact with food, was prepared.

To this, 10 ml of the extract used in Example 2 was added.
Filled and sealed. Prepare a plurality of these pouches,
, And sequentially opened, and the number of bacteria was measured by a pour method using a potato dextrose agar medium and a Brix agar medium. Table 2 shows the results of these measurements.

[0046]

[Table 2]

(Example 3) In the apparatus shown in FIG. 8, polypropylene (PP) 17 which was hot-melted was extruded from a T-die 13 so as to have a final thickness of 1.5 mm, and a first cooling roll 8 and a nip roll 7 were extruded. 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.

The amount of chitosan applied at this time was 3 g / m ² . Using this sheet, a cup-shaped container having an inner capacity 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. (Hereinafter referred to as a cup A.) Further, a lid member for winding made of aluminum having a silver layer (average thickness 0.07 μm) provided on a surface in contact with food by an evaporation method was prepared. (Lid material A)

The cup A was filled with 135 g of purple leaf pickles made of eggplant, cucumber, etc., filled with pickled juice, sealed tightly with a lid material A using a cover material A so that no air bubbles remained, and stored at room temperature. The occurrence of blisters and the like was inspected over time, and the taste was inspected by sequentially opening the package.

(Comparative Example 7) 135 g of the purple leaf pickle used in Example 3 was put into a cup A, filled with pickled juice, and a normal aluminum lid material (lid material B) was used so that no air bubbles remained. And sealed at room temperature. The occurrence of blisters and the like was inspected over time, and the taste was inspected by sequentially opening the package.

(Comparative Example 8) From the PP sheet having a thickness of 1.5 mm, the internal
A 0 ml cup-shaped container was prepared. (Cup B) 135 g of the purple leaf pickle used in Example 3 was put into this cup B, filled with pickled juice, sealed tightly using a cover material A using a lid material A so that no air bubbles remained, and stored at room temperature. . The occurrence of blisters and the like was inspected over time, and the taste was inspected by sequentially opening the package.

(Comparative Example 9) 135 g of the purple leaf pickle used in Example 3 was put into a cup B, filled with pickled juice, sealed tightly with a cover material B using a cover material B so that no air bubbles remained, and kept at room temperature. Saved in. The blisters and the like were inspected over time, and the samples were sequentially opened and inspected for taste.

As a result, the purple leaf pickles of Example 3 had no abnormal appearance such as blistering until 10 days after storage (not performed thereafter), and there was no change in taste and aroma as compared with those before the start of storage. However, those prepared in Comparative Examples 7 and 9 had swelling of the cup 2 days after storage, and the contents had an unusual odor and could not withstand edible use. Three days after storage, the product prepared in Comparative Example 8 had some blisters, and when opened and eaten, it had a strong off-flavor and off-flavor and could not withstand edible use, and the subsequent storage test was stopped.

[0054]

As described above, as shown in the examples, it is possible to extend the preservation period only by packaging foods in which lactic acid bacteria and other microorganisms pose a problem in preservation. Example 1 is an example of a container and a storage method capable of inhibiting the growth of lactic acid bacteria and yeast simply by packaging in the same container. Example 2 is an example of a container and a preservation method capable of simultaneously inhibiting the growth of lactic acid bacteria and other microorganisms simply by packaging. (A bacterium that formed a colony on a Brix agar medium is considered to be a lactic acid bacterium, and a bacterium that formed a colony on a potato dextrose agar medium is considered to be a fungus.) Example 3 is a pickle in which growth of lactic acid bacteria and yeast is a storage problem. On the other hand, this is an example showing that the container and the storage method according to the present invention are effective.

The container and the preservation method according to the present invention are also applicable to preservation of syrups, fruit juices and the like in which the growth of lactic acid bacteria and other microorganisms poses a storage problem. In any of the methods of Example 1, Example 2, Example 3, and Example 4, the method of applying chitosan and silver exhibited a preserving effect, and the container used in the present invention was not limited to any of the methods. It could be made. Further, the preservation method according to the present invention can achieve its purpose only by packaging, so that there is no need to change a conventional manufacturing process, and thus it is very economical.

[0056]

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view taken along a line AA ′ of FIG. 1;

FIG. 3 is a sectional view showing another embodiment of the container of the present invention.

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

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

FIG. 6 is a schematic explanatory view showing 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 showing a step of extruding a resin melted from a T-die to give chitosan.

FIG. 9 is an explanatory sectional view of the chitosan-provided film manufactured according to FIG.

FIG. 10 is a sectional view showing another embodiment of the container of the present invention.

FIG. 11 is an explanatory cross-sectional view showing a lid member manufactured in Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pouch 2 ... K coat nylon film 3 ... Adhesive layer 4 ... Polyethylene kneaded with chitosan and silver zeolite 5 ... Polyethylene 6 ... Layer provided with chitosan 7 ... Nip roll 8 ... First cooling roll 9 ... Second cooling roll 10 ... Laminated body 11 ... K-coated stretched polypropylene film 12 ... Molten polyethylene 13 ... T die 14 ... Flourizer 15 ... Chitosan 16 ... Chitosan applied film 17 ... Molten polypropylene 18 ... Silver zeolite 19 ... Aluminum 20 ... Silver deposited layer

Continuation of the front page (72) Inventor Shoya Sugawara 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. Examiner Ryoichi Mizobuchi (56) References JP-A-3-120204 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B65D 81/28 A23L 3/3562 A23L 3/358

Claims (2)

(57) [Claims] A food preserving method characterized by filling and sealing a food in a container provided with silver and powdered chitosan on at least a part or all of an inner surface in contact with the contents. 2. A container comprising silver and powdered chitosan applied to at least part or all of the inner surface in contact with the contents.