Packaged food, packaging materials, laminates

Abstract

To provide a packaged food which maintains appearance (tint) by suppressing discoloration over time in food, especially a meat product, which has gone through high pressure processing.SOLUTION: A packaged food includes an object to be processed, and a packaging material for packaging the object to be processed. In the packaging material, oxygen permeability is equal to or less than 1.0 mL / m2 day atm. The object to be processed is pressurized and processed in a state of being sealed by the packaging material.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a packaged food obtained by subjecting an object to be processed to a pressure treatment in a sealed state with a packaging material.

Background Art

[0002] Conventionally, it has been known that when heat, pressure, or electron beams are applied to packaged foods or the like for sterilization and disinfection, long-term storage becomes possible. In particular, in recent years, a high-pressure processing method (High Pressure Processing) for inactivating microorganisms by applying extremely high pressure to packaged foods or the like has come to be performed. In this method, inactivation treatment of microorganisms or the like can be performed even at room temperature or a temperature near it. Therefore, there are advantages that heat denaturation of the object to be processed (such as proteins and starches) can be prevented, flavors, nutrients, colors, etc. can be retained, and uniform and spotless treatment can be achieved. On the other hand, since extremely high pressure is also applied to the packaging material, various packaging materials have been proposed.

[0003] Patent Document 1 describes a packaging material for high-pressure treatment having a base material such as a PET film, a gas barrier layer such as an aluminum foil, and an innermost layer such as a cyclic polyolefin or an amorphous polyester. Patent Document 2 describes a packaging material used in a high-pressure sterilization method having a hydrophobic layer such as polypropylene and a saponified ethylene-vinyl acetate copolymer layer. Patent Document 3 describes an ultra-high-pressure treatment multilayer structure having a saponified ethylene-vinyl ester copolymer layer between a base material film such as PET and a heat-sealing layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] When a high-pressure treatment method is applied to foods, particularly sliced meat products such as ham, microbial control can be achieved. However, compared with meat products that have not been subjected to the high-pressure treatment method, there is a problem that discoloration progresses more easily over time, and the appearance (color tone) deteriorates during storage.

[0006] An object of the present invention is to provide a packaged food that suppresses discoloration over time of a food, particularly a meat product, that has been subjected to high-pressure treatment and maintains the appearance (color tone).

MEANS FOR SOLVING THE PROBLEMS

[0007] As a result of intensive studies on the above problems, the inventors have found that by using a packaging material with a specific oxygen permeability for the object to be treated, discoloration of the object to be treated over time due to high-pressure treatment can be suppressed, and a packaged food with excellent stability during storage can be obtained, thereby completing the present invention. That is, the present invention is the following packaged food, packaging material, and laminate.

[0008] The packaged food of the present invention for solving the above problems is a packaged food comprising an object to be treated and a packaging material for packaging the object to be treated, wherein the packaging material has an oxygen permeability of 1.0 mL / m ·day·atm or less, Moisture permeability of 1.0-10 g / m 2 It is a day, (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer, and the (b) intermediate layer includes at least one layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing a deoxidizer, and the object to be treated is characterized in that it has been pressure-treated in a state sealed with the packaging material. According to the packaged food of the present invention, it is possible to provide a packaged food that suppresses discoloration of the object to be treated over time due to pressure treatment and has excellent stability during storage.

[0009] The present invention, which solves the above problems, is a packaged food comprising a product to be processed and a packaging material for packaging the product to be processed, wherein the packaging material has an oxygen permeability (mL / m³). 2 (g / m) for moisture permeability (day·atm) 2 The ratio of (water permeability / oxygen permeability) to day is 3.5 or higher. Moisture permeability of 1.0-10 g / m 2 It is a day, The present invention provides a laminate comprising (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer, wherein the (b) intermediate layer includes at least one of a layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing an oxygen absorber, and the object to be treated is subjected to pressurized treatment while sealed with the packaging material. According to the present invention, it is possible to suppress the aging of the processed material due to pressure treatment and provide a packaged food with excellent stability during storage.

[0010] The present invention, which solves the above problems, is a packaged food comprising a product to be processed and a packaging material for packaging the product to be processed, wherein the packaging material has an oxygen permeability (mL / m³). 2 (day·atm) and moisture permeability (g / m²) 2 If day) satisfies the following condition (1), Moisture permeability of 1.0-10 g / m 2 It is a day, The present invention provides a laminate comprising (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer, wherein the (b) intermediate layer includes at least one of a layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing an oxygen absorber, and the object to be treated is subjected to pressurized treatment while sealed with the packaging material. Y > 4.2X + z Equation (1) (However, X represents oxygen permeability, Y represents water vapor permeability, and z is -1.5.) According to the present invention, it is possible to suppress the aging of the processed material due to pressure treatment and provide a packaged food with excellent stability during storage.

[0011] Furthermore, in one embodiment of the packaged food of the present invention, the pressure during pressurization is 50 MPa or more and 1000 MPa or less, and the temperature during pressurization is 5°C or more and 60°C or less. This feature allows for sterilization without heat treatment of the object being processed.

[0012] Furthermore, in one embodiment of the packaged food of the present invention, the processed product is a meat product. This characteristic further enhances the effect of suppressing fading over time.

[0013] Furthermore, one embodiment of the packaged food of the present invention is characterized in that the processed product is a sliced ​​food product. Slicing the processed material increases its surface area, making it more susceptible to discoloration over time. Therefore, the effects of the present invention are even more pronounced when the processed material is a sliced ​​food product.

[0014] Furthermore, in one embodiment of the packaged food of the present invention, the packaging material comprises a laminate having (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer, wherein the (b) intermediate layer is a layer containing a resin having oxygen gas barrier properties. , and It is characterized by comprising at least one layer selected from layers containing an oxygen absorber. This feature allows the outermost and innermost layers to protect the gas barrier intermediate layer, thus further enhancing the effect of suppressing discoloration over time.

[0015] Furthermore, in one embodiment of the packaged food of the present invention, (c) the innermost layer is a layer made of a heat-sealable resin or resin composition. This feature allows for easy packaging using a heat sealer. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide packaged food products that suppress discoloration over time, particularly meat products, that have undergone high-pressure processing, and maintain their appearance (color).

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic explanatory view showing the structure of the laminate of the present invention. [Figure 2] It is a schematic explanatory view showing the structure of the packaged food of the present invention. [Figure 3] It is a graph showing the change in color of the packaged food after high-pressure treatment using the packaging material of the present invention, the packaged food after high-pressure treatment using the conventional package, and the packaged food without high-pressure treatment using the conventional laminate. [Figure 4] It is a graph showing the relationship between the oxygen permeability and water vapor permeability of the packaging material, and the presence or absence of a change in the color of the packaged food after high-pressure treatment.

Modes for Carrying Out the Invention

[0018] [Laminate] The laminate of the present invention is characterized in that the oxygen permeability is 1.0 mL / m 2 ·day·atm or less. The oxygen permeability is a value measured based on Japanese Industrial Standard (JIS) K 7216-2 "Coulometric method (MOCON method)" (isobaric method) for the laminate before filling the contents. The measurement conditions are 23 °C and humidity 0% RH. The oxygen permeability of the laminate is preferably 0.7 mL / m 2 ·day·atm or less, and more preferably 0.5 mL / m 2 ·day·atm or less. When the oxygen permeability is 1.0 mL / m 2 ·day·atm or less, the packaged food using the packaging material made of the laminate of the present invention, particularly the packaged food of processed meat products (such as ham), can maintain the appearance (color) immediately after high-pressure treatment.

[0019] The water vapor permeability (g / m 2 ·day) of the laminate of the present invention is not particularly limited, but for example, it is 0.1 to 10 g / m 2 ·day. The lower limit value of the water vapor permeability is preferably 1.0 g / m 2• More than 1.5 g / m² 2 • More than 2.0 g / m² 2 • More than 2.5 g / m², and particularly preferably 2.5 g / m² 2 • It is more than 1 day. The upper limit of moisture permeability is preferably 8.0 g / m 2 • Less than 6.0 g / m² 2 • Less than or equal to 5.5 g / m² 2 It is less than or equal to one day. The moisture permeability was measured on the laminate before filling with contents, according to the Japanese Industrial Standard (JIS) Z 0208-1976 "Test Method for Moisture Permeability of Moisture-Proof Packaging Materials (Cup Method)". The measurement condition was 25°C.

[0020] The laminate of the present invention has an oxygen permeability (mL / m³). 2 (g / m) for moisture permeability (day·atm) 2 It is characterized by having a ratio of (water permeability / oxygen permeability) of 3.5 or higher. The ratio of water vapor permeability to oxygen vapor permeability (water vapor permeability / oxygen vapor permeability) is preferably 4.0 or higher, and more preferably 4.5 or higher. There is no particular upper limit to the ratio of water vapor permeability to oxygen vapor permeability (water vapor permeability / oxygen vapor permeability), but for example, it is 10.0 or lower. When the ratio of moisture permeability to oxygen permeability (moisture permeability / oxygen permeability) is 3.5 or higher, packaged foods using the laminated packaging material of the present invention, particularly packaged meat products (such as ham), can maintain their appearance (color) immediately after high-pressure processing.

[0021] Furthermore, the laminate of the present invention has an oxygen permeability (mL / m³). 2 (day·atm) and moisture permeability (g / m²) 2 The following is a characteristic of day) that satisfies the condition of equation (1). Y > 4.2X + z Equation (1) (However, X represents oxygen permeability, Y represents water vapor permeability, and z is -1.5.) When the oxygen permeability and moisture permeability satisfy the conditions of formula (1) above, packaged foods using the packaging material made of the laminate of the present invention, particularly packaged meat products (such as ham), can maintain their appearance (color) immediately after high-pressure processing.

[0022] In equation (1), z is preferably -0.52, more preferably ±0.00, and particularly preferably +0.50.

[0023] As shown in Figure 1, the laminate 1 of the present invention includes a laminated structure in which an oxygen barrier layer is provided in the intermediate layer 3 located between the outermost layer 2 and the innermost layer 4 that is in contact with the contents. Depending on the purpose, other layers can be arbitrarily provided as the intermediate layer.

[0024] (outermost layer) The outermost layer is susceptible to mechanical forces. Therefore, it is preferable to include a resin that has toughness, pinhole resistance, and puncture resistance, as well as a function that protects the inner layer from water and oxygen. Therefore, resins used as the outermost layer include polyolefins, cyclic polyolefin resins, ethylene-(meth)acrylic acid ester copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester-(meth)acrylic acid copolymers, ethylene-vinyl acetate copolymers, acrylic resins, ionomer resins, styrene polymers, polyvinylidene chloride polymers, fluororesins, polyimides, polyimidoamides, silicones, polyesters, polycarbonates, polyamides (nylon), polyurethanes, acetal resins, polysulfone resins, polyarylene ether resins, and cellulose resins. These may be used individually or mixed in combination as a composition. Among the above resins, polyester, polyolefin, and polyamide are preferred due to their ease of availability, processability into films or sheets, and superior mechanical strength and internal visibility when formed into films or sheets.

[0025] Specifically, examples of polyolefins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene (ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-octene copolymer, etc.), ethylene-propylene copolymer, and polypropylene. Examples of cyclic olefin resins include ring-opening metathesis polymers (such as norbornene ring-opening polymers) and addition copolymers of cyclic olefins and olefins (such as ethylene). Examples of styrene-based resins include polystyrene, acrylonitrile-styrene copolymer, and acrylonitrile-butadiene-styrene copolymer. Examples of polyesters include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polyethylene naphthalate, polytrimethylene naphthalate, and polytetramethylene naphthalate. Examples of polyamides include nylon-6 and nylon-6,6.

[0026] (Middle class) The intermediate layer includes a layer containing a resin with oxygen gas barrier properties, a layer consisting of a metal or metal oxide with oxygen gas barrier properties, or a layer containing an oxygen absorber (hereinafter collectively referred to as the "oxygen barrier layer"). <Oxygen barrier layer> The oxygen barrier layer prevents oxygen from entering the inside of the package. The oxygen barrier layer may consist of only one layer or two or more layers. If two or more oxygen barrier layers are provided, they may be of the same type or different types, and their thicknesses may be the same or different.

[0027] In this specification, a resin having oxygen gas barrier properties is defined as one in which an unstretched sample with a film thickness of 20 μm has an oxygen permeability of 5.0 mL / m² when measured at 23°C and 0% RH humidity. 2 This refers to the following: days and ATMs. Resins having oxygen gas barrier properties include, for example, resins having a polyvinyl alcohol (EVA) structure such as vinyl acetate polymer saponified, trifluorovinyl acetate polymer saponified, vinyl formate polymer saponified, vinyl pivalate polymer saponified, butyl vinyl ether polymer saponified, and trimethylsilyl vinyl ether polymer saponified; resins having an ethylene-vinyl alcohol copolymer (EVOH) structure such as ethylene-vinyl acetate copolymer saponified, ethylene-trifluorovinyl acetate copolymer saponified, ethylene-vinyl formate copolymer saponified, ethylene-vinyl pivalate copolymer saponified, ethylene-butyl vinyl ether copolymer saponified, and ethylene-trimethylsilyl vinyl ether copolymer saponified; polyvinylidene chloride polymers containing vinyl chloride as a constituent monomer; and polyamide MDX6 (a condensed polymer of m-xylenediamine and adipic acid).

[0028] Layers made of metals or metal oxides that have oxygen gas barrier properties include layers manufactured by depositing metals or metal oxides. Examples of metals or metal oxides include aluminum, silicon, magnesium, and tin, as well as their oxides. Examples of layers containing an oxygen absorber include a layer in which Ageless (registered trademark, Mitsubishi Gas Chemical Co., Ltd.) is dispersed in the resin listed in the outermost layer section or in a resin having oxygen gas barrier properties. The oxygen barrier layer is preferably made of a resin having oxygen gas barrier properties due to its ease of availability and processing, and its excellent visibility of the contents. Resins having an ethylene-vinyl alcohol copolymer (EVOH) structure and polyvinylidene chloride polymers are more preferred.

[0029] A deposited film of metal or metal oxide can be formed on a substrate that forms the innermost or outermost layer, or an intermediate layer, by, for example, vacuum deposition, sputtering, ion plating, plasma chemical vapor deposition, or thermochemical vapor deposition. (Other middle class) In addition to the oxygen barrier layer, any other layer can be provided in the intermediate layer depending on the purpose (e.g., toughness, pinhole resistance, puncture resistance, moisture barrier properties, or rigidity). For example, the resins or resin compositions listed in the outermost layer section can be cited. Furthermore, generally, vinyl alcohol polymers, ethylene-vinyl alcohol copolymers, and polyamide MDX6, which have oxygen barrier properties, experience a decrease in oxygen barrier properties due to moisture absorption. For this reason, a layer containing a hydrophobic resin may be provided on one or both sides of the oxygen barrier layer.

[0030] (Innermost layer) Since the innermost layer comes into contact with the packaged item and seals it by the seal, it is preferable that the innermost layer be a resin or resin composition with excellent heat-sealing properties and chemical stability. Examples of innermost layers include polyolefins, cyclic olefin resins, acrylic resins, cyclic olefin resins, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylate alkyl copolymers, ethylene-(meth)acrylic acid copolymers, ionomer resins, unsaturated carboxylic acid-modified polyolefin resins, ethylene-(meth)acrylate alkyl ester-unsaturated carboxylic acid copolymers, and amorphous polyesters. Specifically, examples include low-density polyethylene, high-density polyethylene, linear low-density polyethylene (ethylene-hexene copolymer and ethylene-octene copolymer, etc.), ultra-low-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-4-methyl-1-pentene copolymer, polypropylene, cyclic olefin ring-opening polymer, ethylene-cyclic olefin addition copolymer, ethylene-(meth)acrylic acid 2-ethylhexyl copolymer, and ethylene-(meth)acrylic acid copolymer. These may be used individually or mixed in groups of two or more to form a resin composition. Due to their availability, hydrophobic properties for protecting the oxygen barrier layer, and sealing capabilities, polyolefins and cyclic olefin resins and their resin compositions are preferred, and low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-propylene copolymers and ethylene-butene copolymers and their resin compositions are more preferred.

[0031] Furthermore, in order to facilitate the removal of the processed material, it is preferable that the innermost layer, either alone or together with other layers, has easy-peel properties. The easy-peel properties may be of the cohesive peeling type, interlayer peeling type, or interfacial peeling type. Examples of resins or resin compositions having easy-peel properties include resin compositions containing ultra-low density polyethylene, linear low density polyethylene, and polypropylene; resin compositions containing 4-methyl-1-pentene-propylene copolymer and propylene-ethylene-butene copolymer; and resin compositions containing 4-methyl-1-pentene-propylene copolymer and linear low density polyethylene (ethylene-1-hexene copolymer).

[0032] The laminate of the present invention may contain ultraviolet absorbers, antioxidants, heat stabilizers, lubricants, fillers, reinforcing materials, plasticizers, crosslinking agents, light stabilizers, antistatic agents, mold release agents, surfactants, antibacterial and antifungal agents, flame retardants, desiccants, nucleating agents, coupling agents, antifogging agents, and colorants.

[0033] The thickness of the film or sheet when the laminate of the present invention is made into a film or sheet is not particularly limited. The film thickness is preferably 20 μm or more, more preferably 50 μm or more, and even more preferably 70 μm or more. By making the film thickness 20 μm or more, unexpected damage can be prevented and the strength of the film can be improved. Furthermore, the film thickness is preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, and most preferably 150 μm or less. If the film thickness is 300 μm or less, the processability of the film during packaging is improved and the processed material can be easily removed. Furthermore, for food packaging, it is preferable that the contents being processed can be seen from the outside. For this reason, the film or sheet using the laminate of the present invention is preferably transparent.

[0034] [Method for manufacturing laminates] There are no particular limitations on the method for manufacturing a laminated film or sheet. For example, each layer may be manufactured and then laminated, with each layer being bonded together via an adhesive resin layer using an adhesive, heat, or pressure. Alternatively, single-layer films or sheets may be manufactured and then laminated, for example, by dry lamination, extrusion coating, co-extrusion coating, or sand lamination. Furthermore, all or part of the laminated film or sheet may be laminated by co-extrusion. Methods for manufacturing each layer of film or sheet include, for example, film deposition methods such as casting, T-die, cutting, or inflation. Furthermore, each layer may be unstretched or stretched independently. Stretching may be uniaxial stretching, biaxial stretching, or stretching by inflation. Biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching. Sequential biaxial stretching may be tubular stretching or tenter (T-die) stretching. Furthermore, after manufacturing a laminate with each layer remaining unstretched, the entire laminate may be stretched by uniaxial stretching, biaxial stretching, or inflation.

[0035] To enhance adhesion between layers, each layer may be subjected to corona discharge treatment, ozone treatment, electron beam treatment, low-temperature plasma treatment, or glow discharge treatment. Additionally, a primer coat layer, an undercoat layer, and an adhesive layer may be formed on the surface of each layer.

[0036] [Packaging material] The type of packaging is not particularly limited as long as it can seal the product to be processed. Examples include gas pack packaging and vacuum packaging, but vacuum packaging is preferred. Examples of packaging forms include deep draw packaging, skin pack, four-sided seal packaging, three-sided seal packaging, stick packaging, pillow packaging, gusset bag packaging, and standing pouch. Deep draw packaging and skin pack are preferred, with deep draw packaging being more preferred, because they allow for a tight, airtight seal between the contents and the packaging material.

[0037] The shape of the packaging material used for packaging is not particularly limited. For example, it can be in the form of a film, sheet, or tube. Furthermore, surface treatment to improve tear resistance may be applied to facilitate the removal of the processed material.

[0038] The packaging material used may be a single laminate or a combination of two or more laminates. For example, in three-side seal packaging, the object to be treated is placed on a film or sheet, and the package is sealed by folding it over so that the sealant layer is on the inside. Furthermore, in skin packs, for example, the contents to be processed are sealed by sealing the lid and bottom. In this case, different packaging materials may be used for the lid and bottom.

[0039] The sealing can be carried out by any known method. Examples include thermocompression sealing, high-frequency sealing, and ultrasonic sealing.

[0040] In the case of packaging using two or more types of packaging materials, it is preferable that the area of ​​the packaging material using the laminate of the present invention accounts for 50% or more of the area in contact between the packaging material and the object to be processed (hereinafter referred to as the "contact area"). Here, the packaging material using the laminate of the present invention has an oxygen permeability of 1.0 mL / m². 2The packaging material is one in which the oxygen permeability is less than or equal to day·atm, the ratio of moisture permeability to oxygen permeability (moisture permeability / oxygen permeability) is 3.5 or higher, or the oxygen permeability and moisture permeability satisfy the conditions of formula (1) above. In addition, other packaging materials have an oxygen permeability of 15 mL / m³. 2 Packaging materials below the following limits can also be used. Examples of packaging that uses two or more types of packaging materials include packaging that uses a base made of a packaging material using the laminate of the present invention and a base made of another packaging material.

[0041] [Packaged food] The following explanation will use as an example a packaged food 10 in which the product to be processed 12 is deep-draw packaged using a bottom material 11A and a lid material 11B as packaging materials 11, as shown in Figure 2. The bottom material 11A has an oxygen permeability of 1.0 mL / m³. 2 The packaging material used has an oxygen permeability of 15 mL / m³ or less, and the lid material 11B has an oxygen permeability of 15 mL / m³. 2 The following packaging materials were used: • day·atm

[0042] (Bottom material) The base material is manufactured from the laminate of the present invention, occupies more than 50% of the contact area of ​​the packaging material, and prevents oxygen from entering the inside of the package. The base material is a packaging material that shrinks to conform to the shape of the object being processed, making it possible to display the object in a three-dimensional manner.

[0043] In deep-draw packaging, the bottom material deforms to conform to the shape of the object being processed, resulting in a thinner film thickness and a tendency for unevenness. Therefore, the bottom material of deep-draw packaging should be the packaging material of the present invention (with an oxygen permeability of 1.0 mL / m²). 2 It is preferable to use a packaging material that has a humidity level of less than or equal to day·atm, a ratio of moisture permeability to oxygen permeability (moisture permeability / oxygen permeability) of 3.5 or more, or a packaging material in which oxygen permeability and moisture permeability satisfy the conditions of formula (1) above. This further enhances the effect of the present invention in suppressing discoloration of the treated material.

[0044] (lid material) The lid material is a packaging material that functions as a lid for the bottom material, and its shape is not particularly limited, but it is preferable that it is a packaging material that maintains a flat shape. By making the shape of the lid material flat, it is possible to obtain packaged food in which the expiration date and ingredient list can be easily seen. The outermost layer of the lid material is preferably a layer containing a printable resin. The printable resin is a polar resin, and examples include nylon or polyester. Additionally, the lid material can have a printed layer in the middle layer.

[0045] Because the lid material undergoes minimal deformation in deep-draw packaging, it is less susceptible to the effects of high-pressure processing. Therefore, the lid material for deep-draw packaging has an oxygen permeability of 1.0 mL / m³. 2 Packaging materials exceeding 15 mL / m³ can be used. There is no particular upper limit on the oxygen permeability of the lid material for deep-drawn packaging, but for example, 15 mL / m³. 2 • day·atm or less, preferably 10 mL / m² 2 • day·atm or less, more preferably 8 mL / m² 2 It is less than or equal to the day and ATM.

[0046] (Object to be processed) There are no particular restrictions on the materials to be processed. Examples include meat products, seafood products, and vegetable products. Meat products are preferred. Specific examples of meat products include ham, bacon, prosciutto, roast pork, wieners / frankfurters, dried meat, sausages, hamburgers, meatballs, braised pork, salad chicken, smoked chicken, and yakitori. They may also contain liquids or gelatinous substances such as sauces, soups, or jellies. Specific examples of seafood products include sashimi, simmered fish, grilled fish, fish sausage, and dried seafood. Specific examples of vegetable products include cut raw vegetables, boiled vegetables, stir-fried vegetables, and pickles. Since the discoloration of red meat is particularly noticeable in meat and seafood products, the discoloration-suppressing effect of the present invention is even more pronounced.

[0047] The shape of the processed product is not particularly limited, but examples include block processed foods, sliced ​​processed foods, and minced processed foods. When the processed product is sliced ​​or minced, the surface area increases, making it more susceptible to discoloration over time. In addition, since sliced ​​processed foods are displayed with the cut surface facing outwards, discoloration is particularly noticeable. Therefore, when the processed product is a sliced ​​processed food, the discoloration-suppressing effect of the present invention is even more pronounced.

[0048] [Packaging method] For packaging used in high-pressure processing, vacuum packaging is preferred because air pockets can cause whitening of the packaging material. Examples of degassing methods include chamber degassing, mechanical degassing, and nozzle degassing.

[0049] [High-pressure processing method] High-pressure processing is a method of sterilization and disinfection that involves applying extremely high pressure at or near room temperature. Because this method minimizes heat-induced denaturation, it preserves flavor and nutrients, and allows for uniform processing of the entire object being treated. <Pressure> The pressure for high-pressure processing is, for example, between 50 MPa and 1000 MPa. The lower limit of the high-pressure processing pressure is preferably 100 MPa or higher, more preferably 200 MPa or higher, even more preferably 300 MPa or higher, and particularly preferably 450 MPa or higher. The upper limit of the high-pressure processing pressure is preferably 800 MPa or lower, more preferably 700 MPa or lower. If the pressure is 100 MPa or higher, sterilization and disinfection can be achieved, and food can be preserved for a long period of time. If the pressure is 1000 MPa or lower, the intrusion of oxygen and moisture into the inside of the package can be suppressed. The pressurization may be carried out continuously or intermittently. The pressures may be the same or different.

[0050] <Temperature> The temperature for high-pressure processing is preferably between 0°C and 60°C, between 3°C and 50°C, and more preferably between 5°C and 40°C. A temperature above 0°C prevents the processed material from freezing and prevents damage to the package during pressurization. A temperature below 60°C suppresses thermal denaturation of the processed material. The temperature may be uniform or varied during the pressurization process.

[0051] <time> The duration of the high-pressure treatment is not particularly limited. Preferably, it is between 30 seconds and 1800 seconds, more preferably between 60 seconds and 900 seconds, and even more preferably between 150 seconds and 250 seconds. A duration of 30 seconds or more provides sterilization and disinfection effects, allowing the treated material to be stored for a long period. A duration of 1800 seconds or less prevents the treated material from being compressed or hardened. If the pressure is applied intermittently, the duration is the total time of pressure application.

[0052] <Pressurized medium> Water is generally used as the pressurizing medium in high-pressure applications. However, other chemically stable liquids besides water can also be used as the pressurizing medium. To prevent oxygen gas contained in the water from entering the package, it is preferable to use deaerated water or water purged of oxygen gas using an inert gas (such as nitrogen or argon). [Examples]

[0053] The present invention will be specifically described below with reference to examples, but the scope of the invention is not limited by these examples.

[0054] The measurement and evaluation methods used in this invention are as follows. [1] Oxygen permeability These values ​​were measured at 23°C and 0% RH based on the Japanese Industrial Standard (JIS) K 7216-2:2006 "Coulometric Method (MOCON Method)" (isobaric method). [2] Moisture permeability The values ​​were measured at 25°C based on the Japanese Industrial Standard (JIS) Z 0208-1976 "Test Method for Moisture Permeability of Moisture-Proof Packaging Materials (Cup Method)". [3] Evaluation of fading After high-pressure treatment, the color of the treated material was visually evaluated. (Evaluation Criteria) ○: No change in color was observed. △: The color has faded slightly. ×: The colors have faded.

[0055] <Test 1: Visual evaluation of the color of the treated object (1)> [Example 1] The material to be processed is sliced ​​roast ham, and the base material has an oxygen permeability of 0.5 mL / m³. 2 ·day·atm, moisture permeability 3.3g / m 2 • The film (PP / EVOH / NY / PE-based EP, 160 μm thick) and lid material have an oxygen permeability of 1.0 mL / m². 2 ·day·atm, moisture permeability 5.1g / m 2 A film (PP / barrier NY / LLDPE, 95 μm thick) from day was used. The bottom layer was made of PE-based EP as the innermost layer, and the lid layer was made of LLDPE as the innermost layer. Sliced ​​roast ham was placed on the lid, the bottom film was heated and pressed into shape, then the sliced ​​roast ham was covered, a vacuum (1 kPa) was created between the bottom and lid, and the film was sealed to perform deep-draw packaging. The bottom film accounted for more than 50% of the contact area. The manufactured deep-drawn packaged food was subjected to high-pressure processing by using water as the pressurizing medium and applying pressure at a hydrostatic pressure of 600 MPa for 210 seconds. After leaving the treated materials at 10°C until each evaluation day, the color of the treated materials was visually inspected.

[0056] [Example 2] Instead of the bottom material and lid material in Example 1, the bottom material has an oxygen permeability of 0.5 mL / m³. 2 ·day·atm, moisture permeability 2.7g / m 2 • Day film (NY / EVOH / NY / PE-based EP, 250 μm thick) and lid material with oxygen permeability of 4.5 mL / m² 2 ·day·atm, moisture permeability 3.4g / m 2The procedure was the same as in Example 1, except that a film (PP / KNY / LLDPE, 95 μm thick) was used.

[0057] [Example 3] The material to be processed is sliced ​​roast ham, and the base material has an oxygen permeability of 0.5 mL / m³. 2 ·day·atm, moisture permeability 2.7g / m 2 • Day film (NY / EVOH / NY / PE-based EP, 250 μm thick) and lid material with oxygen permeability of 6.5 mL / m² 2 ·day·atm, moisture permeability 3.6g / m 2 A film (PP / KNY / LLDPE, 95 μm thick) from day was used. The innermost layers were a PE-based EP base material and an LLDPE lid material. Sliced ​​roast ham was placed on the lid material, the film that would serve as the base material was heated and pressed into shape, then the film was used to cover the sliced ​​roast ham, a vacuum (1 kPa) was created between the base material and the lid material, and the packaging was sealed to perform deep-draw packaging. The manufactured deep-drawn packaged food was subjected to high-pressure processing by using water as the pressurizing medium and applying pressure at a hydrostatic pressure of 600 MPa for 180 seconds. After leaving the treated materials at 10°C until each evaluation day, the color of the treated materials was visually inspected.

[0058] [Example 4] Instead of the bottom material used in Example 3, a bottom material with an oxygen permeability of 0.6 mL / m³ was used. 2 ·day·atm, moisture permeability 3.2g / m 2 The procedure was the same as in Example 3, except that a film of the same type (NY / EVOH / NY / PE-based EP, 220 μm thick) was used.

[0059] [Example 5] Instead of the bottom material in Example 3, the bottom material has an oxygen permeability of 0.0 mL / m³. 2 ·day·atm, moisture permeability 3.6g / m 2 The procedure was the same as in Example 3, except that a film (NY / oxygen-absorbing layer / PE, 200 μm thick) with a day oxygen-absorbing layer as the intermediate layer was used, and the PE bottom material was used as the innermost layer.

[0060] [Comparative Example 1] Instead of the bottom material and lid material in Example 1, the bottom material has an oxygen permeability of 2.0 mL / m³. 2 ·day·atm, moisture permeability 6.2g / m 2 • Day film (NY / EVOH / NY / PE-based EP, 150 μm thick) and lid material with oxygen permeability of 2.5 mL / m² 2 ·day·atm, moisture permeability 8.0g / m 2 The procedure was the same as in Example 1, except that a film (NY / EVOH / NY / PE, 80 μm thick) was used, and the bottom material was made of PE-based EP and the lid material was made of PE as the innermost layers.

[0061] [Comparative Example 2] Instead of the bottom material and lid material in Example 3, the bottom material has an oxygen permeability of 1.5 mL / m³. 2 ·day·atm, moisture permeability 4.3g / m 2 • The film (PP / EVOH / NY / PE-based EP, 150 μm thick) and lid material have an oxygen permeability of 3.7 mL / m². 2 ·day·atm, moisture permeability 4.7g / m 2 The procedure was the same as in Example 3, except that a film (PP / / NY / EVOH / NY / PE, 80 μm thick) was used and the PE lid material was used as the innermost layer. Note that "PP / / NY / EVOH / NY / PE" is a laminate of PP film and NY / EVOH / NY / PE film.

[0062] [Comparative Example 3] Instead of the bottom material and lid material in Example 3, the bottom material has an oxygen permeability of 1.1 mL / m³. 2 ·day·atm, moisture permeability 2.9g / m 2 • Day film (NY / EVOH / NY / PE-based EP, 250 μm thick) and lid material with oxygen permeability of 2.2 mL / m² 2 ·day·atm, moisture permeability 7.4g / m 2 The procedure was the same as in Example 3, except that a film (NY / EVOH / NY / PE, 100 μm thick) was used and the PE lid material was made the innermost layer.

[0063] [Reference example 1] In Comparative Example 2, the procedure was carried out similarly, except that high-pressure treatment was not performed.

[0064] Table 1 shows the laminate structure, film thickness, oxygen permeability, and moisture permeability used in the Examples, Comparative Examples, and Reference Example 1, and Table 2 shows the results of the high-pressure treatment.

[0065] [Table 1]

[0066] The meanings of the abbreviations in Table 1 are as follows: PP: Polypropylene EVOH: Ethylene-vinyl alcohol copolymer (ethylene-vinyl acetate copolymer) NY: Nylon Barrier NY: Organic acid coated barrier nylon KNY: Polyvinylidene chloride coated nylon PE: Polyethylene LLDPE: Linear low-density polyethylene PE-based EP: Polyethylene-based easy-peel film

[0067] [Table 2]

[0068] A comparison between Reference Example 1 and Comparative Example 2 revealed that the object in Reference Example that was deep-drawn and packaged without high-pressure treatment did not experience discoloration, while the object that underwent high-pressure treatment did experience discoloration.

[0069] In Example 5, where an oxygen absorption layer was provided in the intermediate layer, no discoloration of the treated material occurred even after high-pressure treatment, suggesting that oxygen is influencing the discoloration of the treated material.

[0070] Oxygen permeability is 1.0 mL / m³ 2Materials treated with laminates of 1.0 mL / m³ or less as the base material showed no discoloration for 75 days or more, regardless of the treatment time (Examples 1-5). In contrast, materials with an oxygen permeability of 1.0 mL / m³ showed no discoloration. 2 Materials treated with laminates exceeding 1 / day·atm as the base material showed discoloration (Comparative Examples 1-3).

[0071] <Test 2: Evaluation of color changes using a color difference system> Next, the color changes over time were evaluated for the deep-drawn packaged foods of Example 5, Comparative Example 2, and Reference Example 1 using a colorimeter. Measurements were taken from the outside of the deep-drawn packaged foods in their original state. A "CR-400" colorimeter (manufactured by Konica Minolta Japan, Inc.) was used. The color difference ΔE* was calculated from the L*a*b* value of the deep-drawn packaged food immediately after high-pressure processing or after packaging, and from the L*a*b* of the packaged food after a predetermined number of storage days. The change in ΔE* was evaluated as the change in color of the deep-drawn packaged food. The results are shown in Figure 3.

[0072] Referring to Figure 3, in conventional laminated packaged foods, there was no change in color in the untreated (Reference Example 1) product, whereas in the treated (Comparative Example 2) product, the color of the ham changed significantly. Furthermore, it can be seen that even when packaged food using the laminate of the present invention (Example 5) is subjected to high-pressure treatment, there is no change in the color of the ham being treated, just as with packaged food using a conventional laminate that has not been subjected to high-pressure treatment.

[0073] <Test 3: Visual evaluation of the color of the treated object (2)> In addition to Examples 1-5 and Comparative Examples 1-3, packaged foods were manufactured in the same manner as in Example 1 of Test 1 for Examples 6-10 and Comparative Examples 4 and 5 shown in Table 3. For Examples 6-10 and Comparative Examples 4 and 5, laminates with the oxygen permeability and moisture permeability shown in Table 3 were used as the base material, and the same laminate as in Example 3 shown in Table 1 was used as the lid material. Next, the color changes of the obtained packaged foods were visually evaluated. The evaluation results are shown in Table 3. Examples 1-5 and Comparative Examples 1-3, shown in Table 3, represent the results of Test 1.

[0074] [Table 3]

[0075] Referring to Table 3, when the ratio of moisture permeability to oxygen permeability (moisture permeability / oxygen permeability) was 3.5 or higher, no discoloration occurred for 75 days or more (Examples 1-10). In contrast, treated materials using laminates with a ratio of moisture permeability to oxygen permeability (moisture permeability / oxygen permeability) of less than 3.5 as the base material discolored (Comparative Examples 1-5).

[0076] Next, for the laminates of Examples 1-10 and Comparative Examples 1-5, the relationship between oxygen permeability and water permeability was plotted in Figure 4, with oxygen permeability on the X axis and water permeability on the Y axis. The marks on the plots are symbols indicating the evaluation of discoloration.

[0077] Referring to Figure 4, it was found that Examples 1-10 and Comparative Examples 1-5 have different distributions. Analyzing these distributions, three straight lines (A) to (C) were drawn. (A) From Examples 1 to 10, a straight line was drawn passing through Example 4 and Example 9 (gray circles), which had a small ratio of water vapor permeability to oxygen vapor permeability (water vapor permeability / oxygen vapor permeability). This straight line was given by the following equation (A). Equation (A): Y = 4.2X + 0.68 (B) Next, equation (A) was slid along the Y-axis to draw a straight line passing through Comparative Example 3. This straight line was given by the following equation (B). Equation (B): Y = 4.2X - 1.72 (C) Additionally, a straight line was drawn midway between equations (A) and (B). This straight line was given by the following equation (C). Equation (C): Y = 4.2X - 0.52

[0078] From these results, the oxygen permeability (mL / m³) 2 (day·atm) and moisture permeability (g / m²) 2 It is determined that no discoloration occurred if the following condition (1) is met on day () Y > 4.2X + z Equation (1) (However, X represents oxygen permeability, Y represents water vapor permeability, and z is -1.5.) [Industrial applicability]

[0079] The packaged food of the present invention is used for products to be sterilized or disinfected by a high-pressure processing method. In particular, it is preferably used for meat products and seafood products. The packaging material of the present invention is used for sealing and packaging objects to be processed in high-pressure processing methods. The laminate of the present invention is intended for use as packaging material for objects to be processed in high-pressure processing methods. [Explanation of Symbols]

[0080] 1 Laminate, 2 Outermost layer, 3 Middle layer, 4 Innermost layer, 10 Packaged food, 11 Packaging material, 11A Bottom material, 11B Lid material, 12 Packaged object

Claims

1. A packaged food comprising a product to be processed and a packaging material for packaging the product to be processed, The aforementioned packaging material is Oxygen permeability is 1.0 mL / m³ ２ - less than or equal to the daily ATM, The moisture permeability is 1.0 to 10 g / m²·day. The laminate comprises (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer. The (b) intermediate layer comprises at least one of a layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing an oxygen absorber. A packaged food product characterized in that the product to be processed is subjected to pressure treatment while sealed with the packaging material.

2. A packaged food comprising a product to be processed and a packaging material for packaging the product to be processed, The aforementioned packaging material is Oxygen permeability (mL / m ２ Moisture permeability (g / m) relative to day / atm ２ - The ratio of (water permeability / oxygen permeability) to day is 3.5 or higher. The moisture permeability is 1.0 to 10 g / m²·day. The laminate comprises (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer. The (b) intermediate layer comprises at least one of a layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing an oxygen absorber. A packaged food product characterized in that the product to be processed is subjected to pressure treatment while sealed with the packaging material.

3. A packaged food comprising a product to be processed and a packaging material for packaging the product to be processed, The aforementioned packaging material is Oxygen permeability (mL / m ２ (day / atm) and moisture permeability (g / m) ２ - day) satisfies the following condition (1), The moisture permeability is 1.0 to 10 g / m²·day. The laminate comprises (a) an outermost layer, (b) an intermediate layer, and (c) an innermost layer. The (b) intermediate layer comprises at least one of a layer selected from a layer containing a resin having oxygen gas barrier properties and a layer containing an oxygen absorber. A packaged food product characterized in that the product to be processed is subjected to pressure treatment while sealed with the packaging material. Y>4.2X+z Formula (1) (However, X represents oxygen permeability, Y represents water vapor permeability, and z is -1.5.)

4. The oxygen permeability of the aforementioned packaging material is 0.5 mL / m². ２ ・day・atm or more 1.0mL / m ２ - A packaged food according to any one of claims 1 to 3, wherein the price is less than or equal to 1 day ATM.

5. The packaged food according to any one of Claims 1 to 4, wherein the ratio of moisture permeability (g / m²·day) to oxygen permeability (mL / m²·day·atm) of the packaging material (moisture permeability / oxygen permeability) is 4.0 or more.

6. The packaged food according to any one of claims 1 to 5, characterized in that the pressure of the pressurization treatment is 50 MPa or more and 1000 MPa or less, and the temperature during the pressurization treatment is 5°C or more and 60°C or less.

7. The packaged food according to any one of claims 1 to 6, characterized in that the processed material is a meat product.

8. The packaged food according to any one of claims 1 to 7, characterized in that the processed product is a sliced ​​food product.

9. The packaged food according to any one of claims 1 to 8, characterized in that the innermost layer (c) is a layer made of a heat-sealable resin or resin composition.

10. A packaging material characterized by being used for packaged food according to any one of claims 1 to 9.

11. A laminate characterized by being used in the packaging material described in claim 10.

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