JP7124945B2 - Package manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a raw meat skin pack package and package.

Edible raw meat is, for example, placed on a resin tray and packaged together with the resin tray using a transparent resin film with low oxygen barrier properties, or packaged in a bag-like package and sold at retail (Patent Document 1). It is known that the raw meat packed in this way undergoes ripening in the package.

Japanese Patent No. 6370290

On the other hand, packaged raw meat is desired to have a longer shelf life in addition to an increase in taste due to aging, but conventional packaging for raw meat leaves room for improvement in this respect. ing.

An object of the present invention is to provide a packaging body capable of aging the packaged raw meat to improve its palatability and extending the preservation period of the raw meat more than conventionally.

In order to solve the above problems, the present invention employs the following configuration.
[1]. In a raw meat skin pack package comprising a lid material and a bottom material, the lid material is made of a resin film, and whether the temperature at which the resin film shows a displacement of 2000 μm is 120° C. or higher in a thermomechanical analysis. Alternatively, the resin film has a gel fraction of 30% or more, and the oxygen permeation amount of the lid material is 100 cc/(m ² ·day · atm) under conditions of a temperature of 23 ° C. and a relative humidity of 60%. below, and the oxygen permeation amount of the bottom material is 300 cc/(m ² ·day · atm) or less under conditions of a temperature of 23 ° C. and a relative humidity of 60%, and carcasses obtained from slaughtered beef cattle was primarily stored at 4°C for 2 days in an air atmosphere, and the partial meat obtained from the carcass after the primary storage was covered with an oxygen barrier film having an oxygen permeation amount of 10 cc/(m ² ·day · atm) or less. and then stored in an air atmosphere at 4°C for 5 days for secondary storage, cut out test meat from the sirloin part with a mass of 0.3 kg from the partial meat after secondary storage, and use the lid material and bottom material. Then, the test meat is skin-packed to prepare a plurality of test packages, and the plurality of test packages are subjected to tertiary storage at 4°C in an air atmosphere, and tertiary storage is started. Measure the inosinic acid content I1 in the test meat in the unopened test package _one day after the start of tertiary storage, and measure the test meat in the unopened test package seven days after the start of tertiary storage When measuring the inosinic acid content I ₇ of the following formula (F _I )
(FI) HI _{= I7} / _I1 x _100
A skin pack package for raw meat, wherein the inosinic acid retention rate HI calculated in the formula is 30 to 90% by mass.

[2]. The fresh meat skin pack package according to [1], wherein the test meat in the unopened test package 14 days after the start of tertiary storage has a coliform group count of 0 cfu/g.
[3]. The raw meat according to [1] or [2], wherein the test meat in the unopened test package 14 days after the start of tertiary storage has a general viable cell count of 1×10 ⁶ cfu/g or less. skin pack package for
[4]. The raw meat skin pack package according to any one of [1] to [3], wherein the resin film is irradiated with an electron beam at an absorbed dose of 13 to 300 kGy.
[5]. The raw meat skin pack package according to any one of [1] to [4], wherein the resin film has a displacement of 500 μm or less at a temperature of 100° C. during the thermomechanical analysis.
[6]. The resin film is a multilayer film comprising an outer layer containing polyethylene, a functional layer containing an ionomer and adjacent to the outer layer, an oxygen barrier layer, and a sealant layer containing an ethylene-vinyl acetate copolymer. The raw meat skin pack package according to any one of [1] to [5].
[7]. A packaging body comprising a lid material and a bottom material, in which fresh meat is skin-packed, wherein the lid material is made of a resin film, and the resin film exhibits a displacement of 2000 μm at a temperature of 120° C. or higher in a thermomechanical analysis. Alternatively, the gel fraction of the resin film is 30% or more, and the oxygen permeation amount of the lid material is 100 cc/(m ² day・ atm) or less, and the oxygen permeation amount of the bottom material is 300 cc / (m ² · day · atm) or less under the conditions of a temperature of 23 ° C. and a relative humidity of 60%, and the raw meat is after slaughter The raw meat is cut from the sirloin part obtained from the edible beef cattle, and the raw meat is skin-packed using the lid material and the bottom material to produce the package, and the package is placed in an air atmosphere. , Store at 4 ° C., measure the inosinic acid content I ₁ ' in the raw meat in the unopened package during storage one day after the package is produced, When the content I ₇ ' of inosinic acid in the raw meat in the unopened package during storage was measured after a day, the following formula (F _I ')
(F _I ') HI '= _{I 7} '/I ₁ '×100
A package having an inosinic acid retention rate H _I ' calculated as above of 30 to 90% by mass.

ADVANTAGE OF THE INVENTION According to this invention, the packaged raw meat can be aged, the taste can be improved, and the package body which can extend the preservation period of raw meat more than before is provided.

1 is a cross-sectional view schematically showing an example of a multilayer film that constitutes a skin pack package for raw meat according to one embodiment of the present invention. FIG. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing an example of a raw meat skin pack package according to an embodiment of the present invention;

◎ Skin pack package for raw meat The skin pack package for raw meat according to one embodiment of the present invention (in this specification, may be simply referred to as "package" or "package of the first embodiment") is , a lid material and a bottom material, wherein the lid material is made of a resin film, and the temperature at which the resin film exhibits a displacement of 2000 μm is 120 ° C. or higher during thermomechanical analysis, or the gel content of the resin film rate is 30% or more, the oxygen permeation amount of the lid material is 100 cc/(m ² · day · atm) or less under the conditions of a temperature of 23 ° C. and a relative humidity of 60%, and a temperature of 23 ° C. and a relative humidity of 60%. The amount of oxygen permeation of the bottom material is 300 cc/(m ² ·day · atm) or less under the condition of 60% humidity, and the carcass obtained from the slaughtered beef cattle is treated at 4 ° C. in an air atmosphere. After primary storage for 2 days, partial meat obtained from the carcass after primary storage is vacuum-packaged with an oxygen barrier film having an oxygen permeability of 10 cc/(m ² ·day · atm) or less and placed in an air atmosphere. , Secondary storage at 4 ° C. for 5 days, cutting out test meat of 0.3 kg sirloin part from the partial meat after secondary storage, skin packing the test meat using the lid material and bottom material By doing so, a plurality of test packages are prepared, and the plurality of test packages are tertiary stored at 4 ° C. in an air atmosphere, and the unopened test one day after the start of the tertiary storage. Measure the inosinic acid content I1 in the test meat in the test package, and measure the inosinic acid content I7 in the test meat in the unopened test package _{7 days} after the start of tertiary storage. When measured, the following formula (F _I )
(FI) HI _{= I7} / _I1 x ₁₀₀
The inosinic acid retention rate H _I calculated by is 30 to 90% by mass.

In the raw meat skin pack package of the present embodiment, the temperature at which the resin film constituting the lid material exhibits a displacement of 2000 μm is 120° C. or higher during thermomechanical analysis, or the gel fraction of the resin film is is 30% or more, the lid material has a high followability to the object to be packaged (contained object), and the lid material exhibits high adhesion to the object to be packaged. Therefore, the raw meat skin pack package of this embodiment has desirable characteristics as a skin pack package.

Furthermore, in the raw meat skin pack package of the present embodiment, the amount of oxygen permeation of the lid material and the bottom material is below a certain level. As a result, the raw meat skin pack package of the present embodiment has a high oxygen-blocking property with respect to the packaged item. As a result, the storage period of the raw meat to be packaged is longer than before. Furthermore, in the conventionally packaged raw meat, microorganisms for advancing the ripening are usually newly attached when the fresh meat is packaged. During storage, the aging progresses due to the action of microorganisms originally attached to raw meat, so there is no need to newly attach microorganisms when packaging raw meat.

Inosine 5′-monophosphate (C ₁₀ H ₁₃ N ₄ O ₈ P) in raw meat is a component involved in the delicious taste of raw meat. That is, raw meat with a moderately high inosinic acid content is superior in terms of deliciousness because it gives a stronger umami taste. In the raw meat skin pack package of the present embodiment, the inosinic acid retention rate _HI is 30 to 90% by mass, and the content of inosinic acid in raw meat during storage is maintained at a moderately high level. By aging the raw meat, the palatability of the raw meat can be improved. On the other hand, when the inosinic acid retention rate _HI is excessively low or high, the influence of fluctuations in the inosinic acid content cannot be avoided, and aging of the raw meat enhances the palatability of the raw meat. cannot be improved.

As used herein, the term "skin pack" refers to cardboard, cardboard, a bottom film, a tray, or the like, where a container is placed, a heated film is placed thereon, and a vacuum is drawn in a chamber to remove the film. It means packaging that is tightly fixed to the contents. The name “skin pack” derives from the fact that the film follows the shape of the product and adheres to the product itself like a skin.

<<Bottom Material>>
The bottom material is not particularly limited as long as it has an oxygen permeation rate of 300 cc/(m ² ·day·atm) or less and the test package can be produced.
The bottom material may be a known one.

Under the conditions of a temperature of 23° C. and a relative humidity of 60%, the oxygen permeation amount of the bottom material is 300 cc/(m ² ·day·atm) or less and 260 cc/(m ² ·day · atm) or less. is preferably 200 cc/(m ² ·day·atm) or less, 150 cc/(m ² ·day · atm) or less, 100 cc/(m ² ·day · atm) or less, and 50 cc/(m ² ·day atm) may be any of the following.
On the other hand, the oxygen permeation amount is 0 cc/(m ² ·day·atm) or more.

The oxygen permeation amount of the bottom material under conditions of a temperature of 23° C. and a relative humidity of 60% can be measured according to JIS K 7126-2:2006.

The oxygen permeation amount of the bottom material can be more easily adjusted by, for example, adjusting the types and contents of components contained in the bottom material, the thickness of the bottom material, and the like.

The thickness of the bottom material is preferably 100 μm or more, more preferably 110 μm or more, and even more preferably 120 μm or more. When the thickness of the bottom material is equal to or greater than the lower limit, the strength of the bottom material is further improved.
The thickness of the bottom material is preferably 6000 μm or less. Since the thickness of the bottom material is equal to or less than the upper limit value, excessive thickness of the bottom material is suppressed.
The thickness of the bottom material can be appropriately adjusted within a range set by arbitrarily combining any of the above lower limits and upper limits.

In the bottom material, regardless of the type, all layers may have transparency, the bottom material may have transparency, or all or part of the layers may not have transparency. , the bottom material may not have transparency. In a raw meat skin pack package constructed using a transparent bottom material, the stored raw meat can be easily visually recognized through the bottom material.

A more detailed configuration of the bottom material and a manufacturing method thereof will be described in detail separately.

<<Resin film (lid material)>>
The resin film (lid material) satisfies the conditions of the temperature or gel fraction at which a displacement of 2000 μm is exhibited during thermomechanical analysis, and the oxygen permeation amount, and is capable of producing the test package. If so, it is not particularly limited.
The temperature at which the resin film exhibits a displacement of 2000 μm in thermomechanical analysis (TMA) is 120° C. or higher, or the gel fraction is 30% or higher, so that the heat resistance of the resin film is improved. As a result, the conformability of the resin film to the contents is improved.

In the thermomechanical analysis of the resin film, the temperature at which a displacement of 2000 μm is exhibited is preferably 120° C. or higher, more preferably 120 to 200° C., even more preferably 123 to 190° C., for example , 130 to 190°C. When the temperature is equal to or higher than the lower limit value, the heat resistance of the resin film is further improved, and as a result, the conformability of the resin film to the contents is further improved. When the temperature is equal to or lower than the upper limit, excessive heat resistance of the resin film is suppressed.

In the thermomechanical analysis of the resin film, the displacement at a temperature of 100° C. is preferably 500 μm or less, more preferably 40 to 500 μm, even more preferably 45 to 400 μm. ˜350 μm, 55-340 μm, and 55-250 μm. When the displacement is equal to or less than the upper limit value, the melt tension of the resin film is improved, and as a result, the conformability of the resin film to the contents is further improved. When the displacement is equal to or greater than the lower limit, excessive melt tension of the resin film is suppressed.

The thermomechanical analysis of the resin film is based on JIS K 7196, and the amount of thermal expansion of the sample is measured from the difference in the amount of thermal expansion when the temperature of the standard sample and the sample to be analyzed is increased at a constant rate. It can be done by

In the thermomechanical analysis of the resin film, the temperature at which the displacement of 2000 μm and the displacement at a temperature of 100° C. are obtained by, for example, electron beam irradiation of the resin film. You can adjust by adjusting. For example, when the resin film is a multilayer film to be described later, the temperature and displacement can be more easily adjusted by adjusting the electron beam irradiation conditions for the outer layer or functional layer in the multilayer film.

The resin film is preferably irradiated with electron beams at an absorption dose of 13 to 300 kGy, more preferably electron beam irradiation at an absorption dose of 15 to 250 kGy. Electron beam irradiation may be performed under any condition of 20 to 250 kGy, 45 to 250 kGy, and 70 to 250 kGy. When the absorbed dose is within such a range, both the temperature at which the displacement of 2000 μm and the displacement at a temperature of 100° C. are within the above numerical range during thermomechanical analysis of the resin film. A resin film is obtained more easily. On the other hand, when the absorbed dose is at least the lower limit, the crosslink density of the resin film (in particular, when the resin film is a multilayer film described later, the outer layers and functional layers in the multilayer film) is increased. As a result, the heat resistance and melt tension of the resin film as a whole are further improved. When the absorbed dose is equal to or less than the upper limit, excessive strength of the resin film is suppressed.

The reason why electron beam irradiation improves the crosslink density of the resin film (in particular, when the resin film is a multilayer film described later, the outer layers and functional layers in the multilayer film) is not clear, but the following reasons are not clear. inferred to. That is, when the resin film is irradiated with an electron beam, the carbon-hydrogen bond in the resin (eg, polyethylene, ionomer) is cut, and radicals are generated at the cut bond ends. The generated radicals come into contact with other resin molecular chains (for example, other polyethylene molecular chains, other ionomer molecular chains) due to molecular motion of the molecular chains, extract hydrogen atoms, and form other resin molecular chains ( (For example, other polyethylene molecular chains, other ionomer molecular chains), and as a result, it is assumed that a crosslinked structure is formed.

The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV, more preferably 120 to 280 kV, even more preferably 140 to 260 kV. When the acceleration voltage during electron beam irradiation is within such a range, the temperature at which the displacement of 2000 μm and the displacement at a temperature of 100° C. are both within the above numerical range during thermomechanical analysis of the resin film. The inner resin film can be obtained more easily. On the other hand, when the acceleration voltage during electron beam irradiation is at least the lower limit, the resin film (particularly, when the resin film is a multilayer film described later, the outer layers and functional layers in the multilayer film). The crosslink density is further improved, and as a result, the heat resistance and melt tension of the resin film as a whole are further improved. When the acceleration voltage during electron beam irradiation is equal to or less than the upper limit, excessive strength of the resin film is suppressed.

The gel fraction of the resin film is preferably 30% or more, more preferably 30 to 90%, even more preferably 32 to 85%, such as 40 to 82%, 48 to 82%. %, and 55 to 82%. When the gel fraction of the resin film is equal to or higher than the lower limit, heat resistance and melt tension of the resin film are improved, and as a result, conformability to the contents is improved. When the gel fraction of the resin film is equal to or less than the upper limit, excessive strength of the resin film is suppressed.

The gel fraction of the resin film can be measured according to JIS K 6769 by utilizing the fact that the crosslinked portion of the film does not dissolve in a solvent. That is, the resin film is immersed in an organic solvent such as xylene, the remaining insoluble film is dried, and then the mass of the resulting dried product is measured. The gel fraction can be calculated from the mass of the dried insoluble film. More specifically, for example, a resin film (mass X g) is wrapped with a stainless steel wire mesh (mass Y g), immersed in a heated solvent, and then the resin film wrapped with the stainless steel wire mesh (in other words, the above Remove the insoluble film). Then, it is vacuum-dried, and the mass (Zg) of the resin film (in other words, the insoluble film) wrapped with the stainless wire mesh after drying is measured. and the following formula (1):
Gel fraction (% by mass) of resin film = (ZY)/X x 100 (1)
Then, the gel fraction of the resin film is calculated.

The gel fraction of the resin film is determined, for example, by electron beam irradiation of the resin film (in particular, when the resin film is a multilayer film described later, an outer layer or a functional layer in the multilayer film), It can be adjusted by adjusting the electron beam irradiation conditions at this time. In this case, the electron beam irradiation conditions are the same as those for adjusting the temperature at which a displacement of 2000 μm and the displacement at a temperature of 100° C. are adjusted in the thermomechanical analysis of the resin film described above. Absorbed dose and accelerating voltage for electron beam irradiation can be employed.

The resin film satisfies either one of the above conditions of the temperature at which a displacement of 2000 μm is exhibited in the thermomechanical analysis and the gel fraction, or both of them. That is, the resin film has a temperature at which a displacement of 2000 μm is exhibited during thermomechanical analysis of 120° C. or higher and a gel fraction of less than 30%; is less than 120°C and has a gel fraction of 30% or more; and has a temperature of 120°C or more at which a displacement of 2000 µm is exhibited in thermomechanical analysis and a gel fraction of 30% or more. is mentioned.
Generally, however, the resin film satisfies both of the above conditions, that is, the temperature at which a displacement of 2000 μm is exhibited during thermomechanical analysis is 120° C. or higher, and the gel fraction is 30% or higher. things are preferred.

The oxygen permeation amount of the resin film (lid material) under conditions of a temperature of 23° C. and a relative humidity of 60% is 100 cc/(m ² ·day·atm) or less, and 80 cc/(m ² ·day · atm). ) or less, more preferably 60 cc/(m ² ·day·atm) or less, even more preferably 40 cc/(m ² ·day · atm) or less, and 20 cc/(m ² · day·atm) or less, and may be, for example, 10 cc/(m ² ·day·atm) or less.
On the other hand, the oxygen permeation amount is 0 cc/(m ² ·day·atm) or more.

The oxygen permeation amount of the resin film (lid material) under conditions of a temperature of 23° C. and a relative humidity of 60% can be measured according to JIS K 7126-2:2006.

The amount of oxygen permeation of the resin film (lid material) can be more easily adjusted by, for example, adjusting the types and contents of components contained in the resin film, the thickness of the resin film, and the like.

The thickness of the resin film (lid material) is preferably 60 μm or more, more preferably 70 to 400 μm, even more preferably 80 to 300 μm, and may be, for example, 100 to 200 μm. . When the thickness of the resin film is equal to or greater than the lower limit, the strength of the resin film is further improved. When the thickness of the resin film is equal to or less than the upper limit value, excessive thickness of the resin film is suppressed.

The resin film is preferably a laminated film configured by laminating a plurality of layers.
Preferred examples of the resin film that is a laminated film include an outer layer containing polyethylene, a functional layer containing an ionomer and adjacent to the outer layer, an oxygen barrier layer, and a sealant layer containing an ethylene-vinyl acetate copolymer. and a multilayer film comprising:

In the resin film (lid material), it is preferable that all layers have transparency regardless of the type thereof, and that the resin film has transparency, that is, the resin film is a transparent resin film. . In the raw meat skin pack package constructed using such a resin film, the stored raw meat can be easily visually recognized through the resin film (lid material).

A more detailed configuration of the resin film (lid material) and a manufacturing method thereof will be described in detail separately.

Using the lid material and the bottom material in this embodiment, test meat is skin-packed to prepare a plurality of test packages, and a storage test is performed using these test packages. The inosinic acid retention H _I calculated by the formula (F _I ) is 30 to 90% by mass, preferably 35 to 75% by mass, for example, 45 to 75% by mass, and 55 to 75% by mass. 35 to 62 mass %, 35 to 50 mass %, or 45 to 62 mass %.

In the test package, the carcass obtained from the slaughtered edible beef cattle is primarily stored at 4 ° C. for 2 days (48 hours) in an air atmosphere, and partial meat is obtained from the carcass after the primary storage, 2. The cut meat is vacuum-packaged with an oxygen barrier film having an oxygen permeation rate of 10 cc/(m ² ·day · atm) or less, and is stored in an air atmosphere at 4° C. for 5 days (120 hours) for secondary storage; It can be prepared by cutting out test meat of a sirloin part having a mass of 0.3 kg from the partial meat after the next storage, and skin-packing the test meat using the lid material and the bottom material.
The dressed carcass is subjected to primary storage without packaging.

The oxygen barrier film used for vacuum packaging the carcass after primary storage is not particularly limited as long as the oxygen permeation amount is 10 cc/(m ² ·day·atm) or less. The oxygen permeation amount of the oxygen barrier film is 0 cc/(m ² ·day·atm) or more.
The oxygen permeation amount of the oxygen barrier film is a value measured according to JIS K 7126-2:2006.

The oxygen barrier film may be a monolayer film composed of one layer, or a laminate film composed of two or more layers.
The oxygen barrier film is preferably a laminated film having a polyvinylidene chloride layer (a layer made of polyvinylidene chloride).

Examples of the laminated film include a polyethylene (PE) layer, an ethylene-vinyl acetate copolymer (EVA) layer, a polyvinylidene chloride (PVDC) layer, an ethylene-vinyl acetate copolymer (EVA) layer and ultra-low density polyethylene. (VLDPE) layers laminated in this order in the thickness direction.

In such a laminated film, the ratio of the thickness of the polyethylene layer to the thickness of the entire laminated film is preferably 2 to 50%, and the ratio of the thickness of the polyvinylidene chloride layer is preferably 2 to 50%. Preferably, the thickness ratio of the ultra-low density polyethylene layer is preferably 2 to 50%, and the thickness ratio of one ethylene-vinyl acetate copolymer layer is 2 to 50%. is preferably

The oxygen barrier film preferably has a thickness of 30 to 80 μm.

It is preferable that the mass of the portion of meat to be vacuum-packaged with the oxygen barrier film is 5 to 50 kg.

In the vacuum packaging of the cut meat, the sealing temperature at the time of heat sealing of the oxygen barrier film is preferably 80 to 140°C.
The sealing time during heat sealing can be appropriately adjusted according to the sealing temperature, but is usually preferably 2 to 20 seconds.
It is preferable that the pressure (degree of vacuum) of the region where the partial meat is arranged due to vacuuming during the heat sealing is 5000 Pa (50 mbar) or less.
The meat cuts packaged under such conditions are highly suppressed in quality variation during secondary storage.

After cutting out the test meat from the dressed carcass, the test package can be produced, for example, by a method for manufacturing a raw meat skin pack package according to the present embodiment, which will be described later.

The inosinic acid content I _t in the test meat in the unopened test package t days (t is a number greater than 0) after the start of tertiary storage is measured, for example, by high-performance liquid chromatography. can. More specifically, for example, by high-performance liquid chromatography, a calibration curve for specifying the amount of inosinic acid is prepared in advance, a sample that may contain inosinic acid is collected from the test meat, and this sample Prepare a purified sample from which at least some unnecessary substances have been removed, quantify inosinic acid in this purified sample by high performance liquid chromatography, and use the calibration curve data from the obtained quantitative value , the I _t can be calculated.

The It can also be _measured , for example, by gas chromatography. In this case, as in the case of the high-performance liquid chromatography, a calibration curve for specifying the amount of inosinic acid is prepared in advance by gas chromatography, and the sample that may contain inosinic acid is subjected to the test. A purified sample is prepared by removing at least a part of unnecessary substances from the meat sample, quantifying inosinic acid in the purified sample by gas chromatography, and using the obtained quantitative value, the calibration curve can be used to _calculate the It.

The test package used for the measurement of It was _unopened from the start of _tertiary storage until the measurement of It. In other words, the unsealed test package is not subjected to tertiary storage.

In this embodiment, the number of coliform bacteria in the test meat in the unopened test package 14 days (t=14) after the start of tertiary storage is preferably 0 cfu/g. In the raw meat skin pack package, since the oxygen barrier against the raw meat to be packaged is high, an increase in the number of coliform bacteria in the test meat is suppressed, and the storage period of the packaged raw meat is extended longer than before. be done.

In the present embodiment, the number of general viable bacteria in the test meat in the unopened test package 14 days (t=14) after the start of tertiary storage is 1×10 ⁶ cfu/g or less. is preferred, 8.5×10 ⁵ cfu/g or less is more preferred, and 7×10 ⁵ cfu/g or less is even more preferred. In the raw meat skin pack package, since the oxygen barrier against the raw meat to be packaged is high, the increase in the number of general viable bacteria in the test meat is suppressed, and the storage period of the packaged raw meat is longer than before. be extended.

In this embodiment, a storage test is performed using the test package, and the oleic acid content O1 in the test meat in the unopened test package _one day after the start of tertiary storage is measured. Then, when the oleic acid content O ₇ in the test meat in the unopened test package seven days after the start of the third storage was measured, the following formula (F _O )
(FO) _HO = _O7 / _O1 x ₁₀₀
The retention rate H 2 _O of oleic acid calculated in may be 50 to 150% by mass.

Oleic acid (C ₁₇ H ₃₃ COOH) in raw meat is a component related to the juiciness (juiciness) of raw meat, and raw meat with a moderately high oleic acid content is more juicy (more juicy). It has a moderately high juiciness), so it is excellent in terms of deliciousness. In the raw meat skin pack package of the present embodiment, when the oleic acid retention rate H 2 _O is 50 to 150% by mass, the oleic acid content of the raw meat during storage is maintained at a moderately high level. Thus, aging of the raw meat can further improve the palatability of the raw meat.

The oleic acid content O _t (for example, O ₁ and O ₇ ) in the test meat in the unopened test package t days after the start of tertiary storage (t is a number greater than 0) is , can be measured at the same time as the inosinic acid content I _t (for example, the above I ₁ and I ₇ ).
The _Ot can be measured by gas chromatography in the same manner as the It, except that the object to be measured is oleic acid instead of _inosinic acid. In this case, the I _t and the O _t may be measured from the same sample.

The H 2 _O is preferably 60 to 140% by mass, for example, 80 to 140% by mass, 100 to 140% by mass, and 120 to 140% by mass. %, 60 to 100% by mass, or 60 to 80% by mass, or 80 to 120% by mass.

In this embodiment, a storage test is performed using the test package, and the alanine content A1 in the test meat in the unopened test package _one day after the start of tertiary storage is measured. , when measuring the alanine content A ₇ in the test meat in the unopened test package 7 days after the start of tertiary storage, the following formula (F _A )
(F _A ) H _A = A ₇ /A ₁ ×100
Alanine retention rate H _A calculated in may be 50 to 200% by mass.

Alanine ₍ Alanine, _{H2NCH2CH2COOH} ) in raw meat is a component involved in the sweetness of raw meat, and raw meat with a moderately _high alanine content has a more appropriate degree of sweetness, so it is considered to be delicious. superior in terms of In the raw meat skin pack package of the present embodiment, when the alanine retention rate H _A is 50 to 200% by mass, the alanine content of the raw meat during storage is maintained at a moderately high level. , the aging of the raw meat can further improve the deliciousness of the raw meat.

Alanine content A _t (for example, A ₁ , A ₇ ) in the test meat in the unopened test package t days after the start of tertiary storage (t is a number greater than 0) is It can be measured at the same time as the inosinic acid content I _t (for example, the above I ₁ and I ₇ ).

The A _t can also be measured, for example, by an automated amino acid analysis method. More specifically, for example, a sample that may contain alanine is collected from the test meat, a purified sample is prepared by removing at least a part of unnecessary substances from this sample, and this purified sample is used for automatic amino acid analysis. The A _t can be calculated by the method. In this case, the _Ot and the _At may be measured from the same sample.

The H 2 _A is preferably 60 to 185% by mass, for example, 75 to 185% by mass, 90 to 185% by mass, and 105 to 185% by mass. %, 60 to 145% by mass, and 60 to 125% by mass, or 75 to 165% by mass, 90 to 145% by mass, and 105 to 125% by mass. .

In the raw meat skin pack package of the present embodiment, at least the HI among the HI, the _HO and the _{HA should satisfy} the above conditions, and the _{HI, the HO and} the _HA Either or both of preferably satisfies the above conditions, and more preferably, all of the above H _I , H 2 _O and _HA satisfy the above conditions.

That is, the preferable fresh meat skin pack package includes, for example, a lid material and a bottom material, the lid material is made of a resin film, and the resin film has a temperature of 120 μm at which a displacement of 2000 μm is exhibited during thermomechanical analysis. ° C. or higher, or the gel fraction of the resin film is 30% or higher, and the oxygen permeation amount of the lid material is 100 cc/(m ² · day · atm) or less, the oxygen permeation amount of the bottom material under the conditions of a temperature of 23 ° C. and a relative humidity of 60% is 300 cc / (m ² · day · atm) or less, and edible after slaughter The carcass obtained from beef cattle is primarily stored at 4°C for 2 days in an air atmosphere, and the partial meat obtained from the carcass after the primary storage has an oxygen permeation amount of 10 cc/(m ² ·day · atm) or less. The meat is vacuum-packaged with an oxygen barrier film and stored in an air atmosphere at 4° C. for 5 days. and the bottom material, the test meat is skin-packed to prepare a plurality of test packages, and the plurality of test packages are tertiary stored at 4°C in an air atmosphere. Measure the inosinic acid content I1 in the test meat in the unopened test package ₁ day after the start of the tertiary storage, and measure the unopened test package 7 days after the start of the tertiary storage. When measuring the inosinic acid content I ₇ in the test meat in the following formula (F _I )
(FI) HI _{= I7} / _I1 x ₁₀₀
The inosinic acid retention rate H _I calculated by is 30 to 90% by mass, and
Measure the oleic acid content O1 in the test meat in the unopened test package 1 day after the start of tertiary storage, and measure the content O ₁ in the unopened test package 7 days after the start of tertiary storage. When measuring the oleic acid content _O7 in the test meat, the following formula ( _FO )
(FO) _HO = _O7 / _O1 x ₁₀₀
is 50 to ₁₅₀ % by mass, or
Measure the alanine content A1 in the test meat in the unopened test package ₁ day after the start of tertiary storage, and measure the content A1 of the unopened test package 7 days after the start of tertiary storage. When measuring the alanine content A ₇ in the test meat, the following formula (F _A )
(F _A ) H _A = A ₇ /A ₁ ×100
and a skin pack package for raw meat having an alanine retention rate H _A of 50 to 200% by mass.

The more preferable raw meat skin pack package includes, for example, a lid material and a bottom material, the lid material is made of a resin film, and the resin film exhibits a displacement of 2000 μm at a temperature of 120° C. during thermomechanical analysis. or more, or the gel fraction of the resin film is 30% or more, and the oxygen permeation amount of the lid material is 100 cc/(m ² · day·atm) or less, and the oxygen permeation amount of the bottom material under conditions of a temperature of 23°C and a relative humidity of 60% is 300 cc/(m ² ·day · atm) or less, and a slaughtered edible beef cattle. The carcass obtained from is primarily stored at 4 ° C. for 2 days in an air atmosphere, and the partial meat obtained from the carcass after the primary storage has an oxygen permeation amount of 10 cc / (m ² day atm) or less. Vacuum-packed with a certain oxygen barrier film, secondary storage at 4 ° C. for 5 days in an air atmosphere, cut out test meat of sirloin part with a mass of 0.3 kg from the partial meat after secondary storage, the lid material and A plurality of test packages are prepared by skin-packing the test meat using a bottom material, and the plurality of test packages are stored at 4°C in an air atmosphere for the third time, Measure the inosinic acid content I1 in the test meat in the unopened test package _one day after the start of tertiary storage, and measure the content I1 of the unopened test package 7 days after the start of tertiary storage. When measuring the content _I7 of inosinic acid in the test meat, the following formula (F _I )
(FI) HI _{= I7} / _I1 x ₁₀₀
The inosinic acid retention rate H _I calculated by is 30 to 90% by mass, and
Measure the oleic acid content O1 in the test meat in the unopened test package 1 day after the start of tertiary storage, and measure the content O ₁ in the unopened test package 7 days after the start of tertiary storage. When measuring the oleic acid content _O7 in the test meat, the following formula ( _FO )
(FO) _HO = _O7 / _O1 x ₁₀₀
is 50 to ₁₅₀ % by mass, and
Measure the alanine content A1 in the test meat in the unopened test package ₁ day after the start of tertiary storage, and measure the content A1 of the unopened test package 7 days after the start of tertiary storage. When measuring the alanine content A ₇ in the test meat, the following formula (F _A )
(F _A ) H _A = A ₇ /A ₁ ×100
and a skin pack package for raw meat having an alanine retention rate H _A of 50 to 200% by mass.

In the test package, the I _t , O _t and A _t (in other words, the H _I , H _O and H _A ) adjust, for example, the configuration of the lid or bottom material in the test package. can be adjusted accordingly. For example, during the thermomechanical analysis of the resin film, the followability of the lid material to the test meat ( The I _t , O _t and A _t can be adjusted by adjusting the adhesiveness).
The I _t , O _t and A _t can also be adjusted by adjusting the amount of oxygen permeation of the lid material and the bottom material and adjusting the degree of maturity of the test meat.

The mechanisms by which inosinic acid, oleic acid and alanine are produced in the test meat in the test package are different from each other. In this embodiment, the production amounts of these three components can be adjusted independently of each other by adjusting the configuration of the lid or bottom material in the test package.

The present invention will be described in more detail below with reference to the drawings. In the drawings used in the following description, in order to make it easier to understand the features of the present invention, there are cases where the main parts are enlarged for convenience, and the dimensional ratio of each component is the same as the actual one. not necessarily.

<<One Embodiment of Resin Film (Lid Material)>>
FIG. 1 is a cross-sectional view schematically showing an example of the multilayer film (laminated film) of the resin film (lid material) in this embodiment.
The multilayer film 1 shown here comprises an outer layer 12 , a functional layer 13 adjacent to the outer layer 12 , an oxygen barrier layer 14 and a sealant layer 11 . In the multilayer film 1, the outer layer 12 is one of the outermost layers, and the sealant layer 11 is the other outermost layer.

Furthermore, the multilayer film 1 includes a pinhole-resistant layer 16 disposed on the sealant layer 11 and disposed between the pinhole-resistant layer 16 and the oxygen barrier layer 14 from the sealant layer 11 side to the outer layer 12 side. and the adhesive layer 15 arranged between the oxygen barrier layer 14 and the functional layer 13 .
That is, the multilayer film 1 includes a sealant layer 11, a pinhole-resistant layer 16, an adhesive layer 15, an oxygen barrier layer 14, an adhesive layer 15, a functional layer 13, and an outer layer 12, which are laminated in this order in the thickness direction, It is configured.

<Sealant layer>
The sealant layer 11 contains ethylene-vinyl acetate copolymer (EVA). Since the sealant layer 11 contains the ethylene-vinyl acetate copolymer, the multilayer film 1 exhibits improved easy-peelability due to pseudo-adhesiveness to the adherend.

The sealant layer 11 may contain only an ethylene-vinyl acetate copolymer (that is, may consist of an ethylene-vinyl acetate copolymer), or may contain an ethylene-vinyl acetate copolymer and It may contain other components (in this specification, may be referred to as "other components") (that is, it consists of an ethylene-vinyl acetate copolymer and the other components may be used).

The other components contained in the sealant layer 11 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin that does not correspond to an ethylene-vinyl acetate copolymer.
The other component, which is a resin component, may be a homopolymer that is a polymer of one type of monomer, or a copolymer that is a polymer of two or more types of monomers.
More specific examples of the other components that are resin components include ethylene-methacrylic acid copolymers, ionomers, polyolefins such as polypropylene, and olefinic copolymers such as ethylene-propylene copolymers. . The sealant layer 11 containing these other components (resin component) further improves the easy peel property due to the expression of pseudo-adhesiveness with the adherend.

Examples of the other components, which are non-resin components, include additives known in the art.
Examples of the additives include antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and the like.

The other components contained in the sealant layer 11 may be only one type, or may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrarily depending on the purpose. You can choose.

The ratio of the content of the ethylene-vinyl acetate copolymer in the sealant layer 11 to the total weight of the sealant layer 11 is preferably 65 to 100% by mass, more preferably 70 to 100% by mass, It is more preferably 75 to 100% by mass, and may be, for example, 85 to 100% by mass. When the ratio is equal to or higher than the lower limit, the easy peel property is further improved due to the development of pseudo-adhesiveness with the adherend.
The above ratio is usually the same as the ratio of the content (parts by mass) of the ethylene-vinyl acetate copolymer to the total content (parts by mass) of the components that do not vaporize at room temperature in the sealant layer-forming composition described later. is.

As used herein, the term "ordinary temperature" means a temperature that is not particularly cooled or heated, that is, a normal temperature.

The sealant layer 11 may consist of one layer (single layer), or may consist of multiple layers of two or more layers. When the sealant layer 11 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

In this specification, not only in the case of the sealant layer 11, "the plurality of layers may be the same or different" means "all the layers may be the same or all the layers may be different." may be the same, or only some of the layers may be the same", and further, "multiple layers are different from each other" means "at least one of the constituent materials and thickness of each layer is different from each other" means

Although the thickness of the sealant layer 11 is not particularly limited, it is preferably 4 to 96 μm, more preferably 7 to 93 μm, even more preferably 10 to 90 μm. 50 μm, and 10 to 30 μm. The strength of the sealant layer 11 becomes higher because the thickness of the sealant layer 11 is equal to or more than the lower limit. When the thickness of the sealant layer 11 is equal to or less than the upper limit, the sealant layer 11 is prevented from becoming excessively thick, and the sealing strength increases when the multilayer film 1 is heated and sealed. .
Here, the "thickness of the sealant layer 11" means the thickness of the entire sealant layer 11. For example, the thickness of the sealant layer 11 consisting of a plurality of layers is the total thickness of all layers constituting the sealant layer 11. means the thickness of

An exposed surface 11a of the sealant layer 11 opposite to the outer layer 12 side (in this specification, may be referred to as a "first surface") 11a is a sealing surface.

<Outer layer>
Outer layer 12 includes polyethylene (PE). Since the outer layer 12 contains polyethylene, the crosslink density of the outer layer 12 can be improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side. As a result, the followability of the skin pack package formed using the multilayer film 1 to the contents is improved.

The outer layer 12 may contain only polyethylene (that is, may be made of polyethylene), or may include polyethylene and other components (hereinafter referred to as "other components"). (that is, it may consist of polyethylene and the other components).

The polyethylene contained in the outer layer 12 is preferably low-density polyethylene with a density of 0.945 g/cm ³ or less, more preferably low-density polyethylene with a density of 0.943 g/cm 3 or less, and a density of 0.943 g/cm ³ or less. Low density polyethylene of 941 g/cm ³ or less is more preferable. By including such low-density polyethylene (LDPE), the cross-linking density of the outer layer 12 can be further improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side.

The polyethylene contained in the outer layer 12 may be of one type or two or more types, and when two or more types are used, the combination and ratio thereof can be arbitrarily selected according to the purpose.

The other components included in the outer layer 12 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin other than polyethylene.
Examples of the other component, which is a non-resin component, include the same additives as the other components included in the sealant layer 11 .

The other components contained in the outer layer 12 may be only one kind, or may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof are arbitrarily selected according to the purpose. can.

The ratio of the content of polyethylene in the outer layer 12 to the total weight of the outer layer 12 is preferably 50% by mass or more, more preferably 55 to 100% by mass, and 60 to 100% by mass. More preferably, for example, it may be either 70 to 100% by mass or 85 to 100% by mass. When the ratio is equal to or higher than the lower limit, the crosslink density of the outer layer 12 can be further improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side.
The ratio is generally the same as the ratio of the polyethylene content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the outer layer forming composition described later.

The outer layer 12 may consist of one layer (single layer), or may consist of two or more layers. When the outer layer 12 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the outer layer 12 is not particularly limited, but is preferably 4 to 146 μm, more preferably 7 to 143 μm, even more preferably 10 to 140 μm, such as 10 to 110 μm, 10 to 80 μm. , and 10 to 50 μm. When the thickness of the outer layer 12 is equal to or greater than the lower limit, the crosslink density of the outer layer 12 can be further improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side. Since the thickness of the outer layer 12 is equal to or less than the upper limit value, the excessive thickness of the outer layer 12 is suppressed.
Here, the "thickness of the outer layer 12" means the thickness of the entire outer layer 12. For example, the thickness of the outer layer 12 consisting of a plurality of layers is the total thickness of all layers constituting the outer layer 12. means.

The ratio of the thickness of the outer layer 12 to the thickness of the multilayer film 1 is not particularly limited, but is preferably 10% or more, more preferably 12 to 88%, and more preferably 14 to 86%. More preferred. When the ratio is equal to or higher than the lower limit, the effect obtained by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side becomes higher. When the ratio is equal to or less than the upper limit value, excessive thickness of the outer layer 12 is suppressed.

<Function layer>
Functional layer 13 comprises an ionomer and is adjacent to outer layer 12 . Since the functional layer 13 contains an ionomer, the crosslink density of the functional layer 13 can be improved when the multilayer film 1 is irradiated with an electron beam from the outside on the outer layer 12 side. As a result, the followability to the contents of the skin pack package constructed using the multilayer film 1 is further improved.

The functional layer 13 may contain only an ionomer (that is, may consist of an ionomer), or may contain an ionomer and other components (hereinafter referred to as "other components"). ) (that is, it may consist of an ionomer and the other component).

As the ionomer contained in the functional layer 13, for example, a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid has an ion-bridged structure due to salt formation between an acid portion therein and a metal ion. A resin that has

Examples of the metal ions include sodium ions and zinc ions. In this specification, ionomers in which the metal ions are sodium ions are sometimes referred to as sodium ionomers, and ionomers in which the metal ions are zinc ions are sometimes referred to as zinc ionomers.

The functional layer 13 may contain only one kind of ionomer, or two or more kinds thereof. When two or more kinds of ionomers are contained, the combination and ratio thereof can be arbitrarily selected according to the purpose.

The other components included in the functional layer 13 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin other than the ionomer.
Examples of the other component, which is a non-resin component, include the same additives as the other components included in the sealant layer 11 .

The other components contained in the functional layer 13 may be one type or two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrarily selected depending on the purpose. You can choose.

The ratio of the ionomer content in the functional layer 13 to the total mass of the functional layer 13 is preferably 50% by mass or more, more preferably 55 to 100% by mass, and 60 to 100% by mass. More preferably, for example, it may be either 70 to 100% by mass or 85 to 100% by mass. When the ratio is equal to or higher than the lower limit, the crosslink density of the functional layer 13 can be further improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side.
The ratio is usually the same as the ratio of the ionomer content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming a functional layer described later.

The functional layer 13 may consist of one layer (single layer), or may consist of multiple layers of two or more layers. When the functional layer 13 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the functional layer 13 is preferably 4 to 146 μm, more preferably 7 to 143 μm, even more preferably 10 to 140 μm, for example 10 to 110 μm, 10 to 80 μm, 10 to 50 μm. , and 10 to 30 μm. When the thickness of the functional layer 13 is equal to or greater than the lower limit, the crosslink density of the functional layer 13 can be further improved by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side. Since the thickness of the functional layer 13 is equal to or less than the upper limit value, the excessive thickness of the functional layer 13 is suppressed.
Here, the "thickness of the functional layer 13" means the thickness of the entire functional layer 13. For example, the thickness of the functional layer 13 consisting of multiple layers is the total thickness of all layers constituting the functional layer 13. means the thickness of

The ratio of the thickness of the functional layer 13 to the thickness of the multilayer film 1 is not particularly limited, but is preferably 10% or more, more preferably 11 to 89%, and 12 to 88%. is more preferred. When the ratio is equal to or higher than the lower limit, the effect obtained by irradiating the multilayer film 1 with an electron beam from the outside on the outer layer 12 side becomes higher. When the ratio is equal to or less than the upper limit, excessive thickness of the functional layer 13 is suppressed.

<Oxygen barrier layer>
The oxygen barrier layer 14 provides the multilayer film 1 with a strong oxygen barrier property (in other words, a property of suppressing permeation of oxygen gas).

The oxygen barrier layer 14 preferably contains an ethylene-vinyl alcohol copolymer (EVOH, also known as saponified ethylene-vinyl acetate copolymer). The oxygen barrier property of the multilayer film 1 provided with such an oxygen barrier layer 14 is further enhanced.

The oxygen barrier layer 14 may contain only an ethylene-vinyl alcohol copolymer (that is, may consist of an ethylene-vinyl alcohol copolymer), or may contain an ethylene-vinyl alcohol copolymer and It may contain other components (in this specification, sometimes referred to as "other components") (that is, it consists of an ethylene-vinyl alcohol copolymer and the other components). may be).

The other components contained in the oxygen barrier layer 14 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin other than the ethylene-vinyl alcohol copolymer.
Examples of the other component, which is a non-resin component, include the same additives as the other components included in the sealant layer 11 .

The other components contained in the oxygen barrier layer 14 may be of only one type, or may be of two or more types, and when two or more types are used, their combination and ratio may be arbitrarily determined according to the purpose. You can choose.

The content of the ethylene-vinyl alcohol copolymer in the oxygen barrier layer 14 is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, with respect to the total mass of the oxygen barrier layer 14. It is preferably 70 to 100% by mass, and may be, for example, 85 to 100% by mass. When the ratio is equal to or higher than the lower limit, the multilayer film 1 has higher oxygen barrier properties.
The ratio is usually the ratio of the content (parts by mass) of the ethylene-vinyl alcohol copolymer to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an oxygen barrier layer, which will be described later. are the same.

The oxygen barrier layer 14 may consist of one layer (single layer), or may consist of multiple layers of two or more layers. When the oxygen barrier layer 14 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the oxygen barrier layer 14 is preferably 2 to 100 μm, more preferably 3 to 90 μm, even more preferably 4 to 80 μm. It may be anywhere from ˜20 μm. When the thickness of the oxygen barrier layer 14 is equal to or greater than the lower limit value, the oxygen barrier property of the multilayer film 1 is further enhanced. Since the thickness of the oxygen barrier layer 14 is equal to or less than the upper limit value, the oxygen barrier layer 14 is prevented from becoming excessively thick.
Here, the “thickness of the oxygen barrier layer 14” means the thickness of the entire oxygen barrier layer 14. For example, the thickness of the oxygen barrier layer 14 consisting of a plurality of layers refers to the thickness of all the oxygen barrier layers 14 constituting the oxygen barrier layer 14. means the total thickness of the layers of

The ratio of the thickness of the oxygen barrier layer 14 to the thickness of the multilayer film 1 is not particularly limited, but is preferably 1% or more, more preferably 2 to 30%, and 3 to 25%. is more preferred. When the ratio is equal to or higher than the lower limit, the multilayer film 1 has higher oxygen barrier properties. When the ratio is equal to or less than the upper limit, the oxygen barrier layer 14 is prevented from becoming excessively thick.

In the case of skin pack packages for foods, the multi-layer film constituting the skin pack packages is required to have an oxygen barrier layer in order to suppress oxidative deterioration of the food. However, there is a problem that the presence of the oxygen barrier layer reduces the conformability of the skin pack package to food (property of adhering to food without causing wrinkles). On the other hand, the skin pack package constructed using the multilayer film 1 of the present embodiment having the outer layer 12 and the functional layer 13 solves such problems. The reason for this is that the presence of the outer layer 12 and the functional layer 13 improves the heat resistance and melt tension of the multilayer film 1, and as a result, the multilayer film 1 has excellent conformability to the contents. .

<Adhesive layer>
The adhesive layer 15 contains an adhesive.
Adhesive layer 15 adheres two adjacent layers on both sides thereof. In the multilayer film 1, the adhesive layer 15 disposed between the anti-pinhole layer 16 and the oxygen barrier layer 14 bonds the anti-pinhole layer 16 and the oxygen barrier layer 14, and the oxygen barrier layer 14 and the functional layer The adhesive layer 15 disposed between the oxygen barrier layer 14 and the functional layer 13 adheres to each other. In this specification, in order to distinguish these two adhesive layers 15 from each other, the adhesive layer 15 disposed between the anti-pinhole layer 16 and the oxygen barrier layer 14 is referred to as the first adhesive layer, if necessary. The adhesive layer 15 which is called the layer 151 and which is arranged between the oxygen barrier layer 14 and the functional layer 13 is sometimes called the second adhesive layer 152 .
These two adhesive layers 15 (first adhesive layer 151 and second adhesive layer 152) may be the same or different.

The adhesive contained in the adhesive layer 15 is not particularly limited as long as it can adhere two layers to be adhered with sufficient strength.
Examples of the adhesive include adhesive resins such as olefin resins (that is, polymers of olefins that are one or more monomers).

More specific examples of the olefin-based resin contained in the adhesive layer 15 include ethylene-based copolymers, propylene-based copolymers, butene-based copolymers, and the like.
The ethylene-based copolymer is a copolymer of ethylene and a monomer other than ethylene.
The propylene-based copolymer is a copolymer of propylene and a monomer other than propylene.
The butene-based copolymer is a copolymer of butene and a monomer other than butene.

Examples of the ethylene copolymer contained in the adhesive layer 15 include a copolymer of ethylene and a vinyl group-containing monomer.
Examples of copolymers of ethylene and vinyl group-containing monomers include maleic anhydride graft-modified linear low-density polyethylene, ethylene-vinyl acetate copolymer (EVA), and ethylene-methyl acrylate copolymer (EMA). , ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-acrylic Ethyl acid-maleic anhydride copolymers (E-EA-MAH), ionomers (ION), ethylene-based thermoplastic elastomers, and the like can be mentioned.
The ionomer includes, for example, the same ionomers as the ionomers included in the functional layer 13 .

Examples of the propylene-based copolymer contained in the adhesive layer 15 include a copolymer of propylene and a vinyl group-containing monomer.
Examples of copolymers of propylene and vinyl group-containing monomers include maleic anhydride graft-modified linear low-density polypropylene and propylene-based thermoplastic elastomers.

Examples of the butene-based copolymer included in the adhesive layer 15 include a copolymer of 1-butene and a vinyl group-containing monomer, a copolymer of 2-butene and a vinyl group-containing monomer, and modifications of these copolymers. products (modified copolymers) and the like.

The adhesive layer 15 may contain only an adhesive (that is, may consist of an adhesive), or may include an adhesive and other components (in this specification, "other components"). ) (that is, it may consist of an adhesive and the other components).

The adhesive layer 15 may contain only one kind of adhesive, or two or more kinds thereof, and when two or more kinds of adhesives are contained, the combination and ratio thereof can be arbitrarily selected according to the purpose. .

The other components included in the adhesive layer 15 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.

The other components contained in the adhesive layer 15 may be of only one type, or may be of two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrarily determined according to the purpose. You can choose.

The content ratio of the adhesive in the adhesive layer 15 to the total mass of the adhesive layer 15 may be, for example, 50 to 100% by mass.
The ratio is usually the same as the ratio of the content (parts by mass) of the adhesive to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an adhesive layer, which will be described later.

The adhesive layer 15 may consist of one layer (single layer), or may consist of multiple layers of two or more layers. When the adhesive layer 15 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the adhesive layer 15 is preferably 4 to 96 μm, more preferably 7 to 93 μm, for example, 7 to 80 μm, 7 to 60 μm, 7 to 40 μm, and 7 to 20 μm. may When the thickness of the adhesive layer 15 is equal to or greater than the lower limit value, the adhesive strength between the two layers to be adhered becomes higher. Since the thickness of the adhesive layer 15 is equal to or less than the upper limit value, the excessive thickness of the adhesive layer 15 is suppressed.
Here, the "thickness of the adhesive layer 15" means the thickness of the entire adhesive layer 15 (for example, the thickness of the entire adhesive layer 15 disposed between the anti-pinhole layer 16 and the oxygen barrier layer 14, The total thickness of the adhesive layer 15 disposed between the oxygen barrier layer 14 and the functional layer 13). It means the total thickness of the layers.

<Anti-pinhole layer>
The multi-layer film 1 may not have the pinhole-resistant layer 16, but the pinhole-resistant layer 16 increases its pinhole resistance. In the package constructed using this multilayer film 1, it is possible to suppress the reduction in strength during the heat treatment.

The pinhole resistant layer 16 preferably contains an ionomer. Since the anti-pinhole layer 16 contains an ionomer, the anti-pinhole property of the multilayer film 1 is further enhanced, and when the multilayer film 1 is irradiated with an electron beam from the outside on the outer layer 12 side, the anti-pinhole The crosslink density of the hole layer 16 can be improved. As a result, the followability to the contents of the skin pack package constructed using the multilayer film 1 is further improved.

The pinhole-resistant layer 16 may contain only an ionomer (that is, may consist of an ionomer), or may contain an ionomer and other components (in this specification, "other components"). (that is, it may consist of an ionomer and the other components).

The ionomer contained in the pinhole-resistant layer 16 includes, for example, the same ionomers as those contained in the functional layer 13 .

The ionomer contained in the anti-pinhole layer 16 may be of only one type, or may be of two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrarily selected according to the purpose. can.

The other components contained in the pinhole resistant layer 16 are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin other than the ionomer.
Examples of the other component, which is a non-resin component, include the same additives as the other components included in the sealant layer 11 .

The other components contained in the anti-pinhole layer 16 may be of only one type, or may be of two or more types. Can be selected arbitrarily.

The ratio of the ionomer content in the pinhole-resistant layer 16 to the total mass of the pinhole-resistant layer 16 is preferably 50% by mass or more, more preferably 55 to 100% by mass, and 60 to 100%. % by mass is more preferable, and for example, it may be either 70 to 100 mass % or 85 to 100 mass %. When the ratio is equal to or higher than the lower limit, the effect obtained by including the ionomer in the multilayer film 1 becomes higher.
The ratio is usually the same as the ratio of the ionomer content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the pinhole resistant layer-forming composition described later.

The pinhole-resistant layer 16 may consist of one layer (single layer), or may consist of multiple layers of two or more layers. When the pinhole resistant layer 16 is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the anti-pinhole layer 16 is preferably 4 to 146 μm, more preferably 7 to 143 μm, even more preferably 10 to 140 μm, such as 10 to 110 μm, 10 to 80 μm, and It may be anywhere from 10 to 50 μm. When the thickness of the pinhole-resistant layer 16 is equal to or greater than the lower limit, the multi-layer film 1 has higher pinhole resistance. By setting the thickness of the pinhole-resistant layer 16 to be equal to or less than the upper limit value, the pinhole-resistant layer 16 is prevented from becoming excessively thick.
Here, the "thickness of the anti-pinhole layer 16" means the thickness of the entire anti-pinhole layer 16. For example, the thickness of the multi-layered anti-pinhole layer 16 is means the total thickness of all the layers that make up the

The ratio of the thickness of the pinhole-resistant layer 16 to the thickness of the multilayer film 1 is not particularly limited, but is preferably 10% or more, more preferably 11 to 89%, and more preferably 12 to 88%. It is even more preferable to have When the ratio is equal to or higher than the lower limit, the multi-layer film 1 has higher pinhole resistance. When the ratio is equal to or less than the upper limit, it is possible to prevent the pinhole-resistant layer 16 from becoming excessively thick.

<Other layers>
The multilayer film 1 includes any of the sealant layer 11, the outer layer 12, the functional layer 13, the oxygen barrier layer 14, the adhesive layer 15, and the anti-pinhole layer 16 within a range that does not impair the effects of the present invention. Other layers may also be provided that do not fall under

The type and arrangement position of the other layer are not particularly limited, and can be arbitrarily selected according to the purpose.

The other layers provided in the multilayer film 1 may be of only one type, or may be of two or more types. Can be selected arbitrarily.

Each of the other layers may consist of one layer (single layer) or may consist of two or more layers. When the other layer is composed of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the other layer can be arbitrarily set according to its type, and is not particularly limited.

When the multilayer film 1 includes the other layer, the multilayer film 1 may further include an adhesive layer (for example, an adhesive layer 15 or the like) for bonding the other layer to other layers.

The thickness of the multilayer film 1 is the same as the thickness of the resin film (lid material) described above.

The multilayer film in this embodiment is not limited to the above-described one, and part of the configuration may be changed, deleted, or added within the scope of the present invention.
For example, the multilayer film may not include any one or more of the pinhole-resistant layer, the adhesive layer, and the functional layer. However, as shown in FIG. 1, the multilayer film comprises a sealant layer, a pinhole-resistant layer, an adhesive layer, an oxygen barrier layer, an adhesive layer, a functional layer, and an outer layer in this order. is preferred.

<<Method for manufacturing resin film (lid material)>>
The resin film (lid material) can be produced by a known method depending on the type.
For example, a laminated film such as the multilayer film can be produced by a feed block method in which resins, resin compositions, etc., which are the materials for forming each layer, are melt-extruded using several extruders, or a co-extrusion T die such as a multi-manifold method. method, air-cooled or water-cooled co-extrusion inflation method, or the like.

In addition, the laminated film is obtained by coating the surface of another layer for forming the laminated film with a resin, a resin composition, or the like, which is a material for forming one of the layers therein, and drying it as necessary. Therefore, it can be produced by forming a laminated structure in the laminated film and, if necessary, further laminating layers other than these so as to obtain the intended arrangement form.

In addition, the laminated film is obtained by separately preparing two or more films for constituting two or more layers of them in advance, and using an adhesive to laminate these films by a dry lamination method, an extrusion lamination method, It can also be manufactured by laminating and laminating by either a hot-melt lamination method or a wet lamination method, and if necessary, further laminating layers other than these so as to have the intended arrangement form. At this time, an adhesive capable of forming the adhesive layer may be used as the adhesive.

In addition, the laminated film is obtained by laminating two or more films separately prepared in advance as described above by laminating them by a thermal (heat) laminating method or the like without using an adhesive. Accordingly, it can also be produced by further laminating layers other than these so as to obtain a desired arrangement form.

When manufacturing the laminated film, two or more methods for forming any layer (film) in the laminated film described above may be combined.

In any case of the production method, the resin composition, which is a material for forming one of the layers in the laminated film, contains the target component (constituent material) of the layer to be formed, and the target content It may be produced by adjusting the type and content of the ingredients so that it is contained in. For example, the content ratio of the components that do not vaporize at room temperature in the resin composition is usually the same as the content ratio of the components in the layer formed from the resin composition.

As a resin composition for forming the sealant layer (the sealant layer 11 in the multilayer film 1 shown in FIG. 1) (herein sometimes referred to as a "sealant layer-forming composition"), for example , the ethylene-vinyl acetate copolymer, and, if necessary, the other components.

As the resin composition for forming the outer layer (outer layer 12 in the multilayer film 1 shown in FIG. 1) (herein sometimes referred to as "outer layer forming composition"), for example, the polyethylene and, if necessary, the other components.

As the resin composition for forming the functional layer (the functional layer 13 in the multilayer film 1 shown in FIG. 1) (herein sometimes referred to as a "functional layer forming composition"), for example , the ionomer, and optionally the other components.

As a resin composition for forming an oxygen barrier layer (oxygen barrier layer 14 in the multilayer film 1 shown in FIG. 1) (herein, sometimes referred to as "oxygen barrier layer-forming composition") Examples include those containing the ethylene-vinyl alcohol copolymer and, if necessary, the other components.

A resin composition for forming a pinhole-resistant layer (in the multilayer film 1 shown in FIG. 1, the pinhole-resistant layer 16) (in this specification, it may be referred to as a "pinhole-resistant layer-forming composition"). A) includes, for example, those containing the ionomer and, if necessary, the other components.

As the resin composition for forming the adhesive layer (adhesive layer 15 in the multilayer film 1 shown in FIG. 1) (herein sometimes referred to as "adhesive layer forming composition"), for example , the adhesive, and, if necessary, the other components.

<< one embodiment of the bottom material >>
The bottom material is preferably a laminate formed by laminating a plurality of layers.
A preferred example of the bottom material that is a laminate is a resin laminate comprising a foamed resin layer and a non-foamed resin layer provided on the foamed resin layer.

The foamed resin layer may be a known one.
Examples of the foamed resin layer include a resin layer containing a polystyrene resin (PSP) foam.

Although the density of the foamed resin layer is not particularly limited, it is preferably 0.05 to 0.5 g/cm ³ .
The expansion rate of the foamed resin layer is not particularly limited, but is preferably 2 to 20 times.
Although the thickness of the foamed resin layer is not particularly limited, it is preferably 500 to 6000 μm.

As the non-foamed resin layer, for example, an easy-peel layer, an oxygen barrier layer, a pinhole-resistant layer, and an adhesive layer are laminated in this order in the thickness direction. film. In the multilayer film for bottom material, the easy peel layer is one of the outermost layers, and the adhesive layer is the other outermost layer.

The multilayer film for bottom material may have, for example, an intermediate adhesive layer between the easy peel layer and the oxygen barrier layer for bonding these two layers.
Further, the multilayer film for bottom material may comprise, for example, an intermediate adhesive layer between the oxygen barrier layer and the pinhole resistant layer for bonding these two layers.
That is, the multilayer film for a bottom material includes an easy peel layer, an intermediate adhesive layer, an oxygen barrier layer, an intermediate adhesive layer, an anti-pinhole layer, and an adhesive layer in this order in the thickness direction. It may be laminated and constructed.

In this specification, in order to distinguish these two intermediate adhesive layers from each other, the intermediate adhesive layer disposed between the easy peel layer and the oxygen barrier layer is referred to as the first intermediate adhesive layer as necessary. layer, and the intermediate adhesive layer disposed between the oxygen barrier layer and the pinhole resistant layer may be referred to as a second intermediate adhesive layer.
These two intermediate adhesive layers (first intermediate adhesive layer, second intermediate adhesive layer) may be the same or different.

<Easy peel layer>
Examples of the easy-peel layer in the multilayer film for bottom material include those exhibiting peelability due to cohesive failure.
Examples of the easy peel layer exhibiting peelability due to cohesive failure include those containing two incompatible polyolefins.

The two incompatible polyolefins contained in the easy peel layer in the multilayer film for bottom material include, for example, an ethylene-based polymer having at least structural units derived from ethylene and at least a structural unit derived from propylene. and a propylene-based polymer having
That is, examples of the easy peel layer include those containing an ethylene-based polymer having at least structural units derived from ethylene and a propylene-based polymer having at least structural units derived from propylene.

Examples of the ethylene-based polymer contained in the easy peel layer in the multilayer film for bottom material include ethylene homopolymers and ethylene-based copolymers.

Examples of the homopolymer of ethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene catalyst linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), and high density polyethylene. (HDPE) and the like.

The ethylene-based copolymer has a structural unit derived from ethylene and a structural unit derived from a monomer other than ethylene.
Examples of the ethylene copolymer include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-acrylic acid Ethyl copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ionomer (ION) and the like.
The ionomer includes, for example, the same ionomers as those included in the functional layer 13 in the multilayer film 1 described above.

The easy peel layer in the multilayer film for bottom material preferably contains low-density polyethylene as the ethylene-based polymer. The easy peel property of such an easy peel layer is better.

Examples of the propylene-based polymer contained in the easy-peel layer in the multilayer film for bottom material include homopolymers of propylene (that is, polypropylene or homopolypropylene, hPP) and propylene-based copolymers.

The propylene-based copolymer has a structural unit derived from propylene and a structural unit derived from a monomer other than propylene.
Examples of the propylene-based copolymer include propylene-ethylene random copolymer (also: polypropylene random copolymer, rPP), propylene-ethylene block copolymer (also: polypropylene block copolymer, bPP), and the like.

The easy peel layer in the multilayer film for bottom material preferably contains polypropylene as the propylene-based polymer. The easy peel property of such an easy peel layer is better.

The component that exhibits easy peel property contained in the easy peel layer in the multilayer film for bottom material may be one type or two or more types, and when two or more types are used, a combination thereof. and the ratio can be arbitrarily selected depending on the purpose. For example, when the components that exhibit easy peel properties are the two types of incompatible polyolefins described above, the easy peel layer may contain only one type of these polyolefins, or two or more types of polyolefins. There may be.

In the easy peel layer in the multilayer film for bottom material, the ratio of the content (parts by mass) of the ethylene-based polymer to the total content (parts by mass) of the ethylene-based polymer and the propylene-based polymer is 10. It is preferably up to 90% by mass, and may be, for example, 30 to 90% by mass, 45 to 90% by mass, or 60 to 90% by mass. When the ratio is equal to or higher than the lower limit, the easy peel property of the easy peel layer becomes better. Peel strength becomes more stable because the said ratio is below the said upper limit.
The ratio is usually the content (mass part) is the same as

The easy-peel layer in the multi-layer film for bottom material contains other components in addition to the components exhibiting easy-peelability (for example, the two incompatible polyolefins described above) within a range that does not impair the easy-peelability. You can
The other components contained in the easy peel layer may be one type or two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary depending on the purpose. can be selected to

In the easy peel layer in the bottom material multilayer film, the ratio of the content of components that exhibit easy peel properties to the total mass of the easy peel layer (for example, the total content of the two incompatible polyolefins described above) ratio) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, for example, 80 to 100% by mass, 90 to 100% by mass, 95 to 100% by mass, 97 to 100% by mass % by mass, and 99 to 100% by mass. When the ratio is equal to or higher than the lower limit, the easy peel property of the easy peel layer becomes better.
The ratio is usually the ratio of the content (parts by mass) of the component that exhibits easy peelability to the total content (parts by mass) of the components that do not vaporize at room temperature in the easy-peel layer-forming composition for the bottom material described later. Same as percentage.

Examples of the other components contained in the easy peel layer in the multilayer film for bottom material include antifogging agents and antiblocking agents.

The easy-peel layer in the multi-layer film for bottom material may consist of one layer (single layer) or may consist of two or more layers. When the easy peel layer consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the easy peel layer in the multilayer film for bottom material is preferably 2 to 50 μm. When the thickness of the easy peel layer is equal to or greater than the lower limit, the seal strength of the easy peel layer is moderately high. Easy peel property becomes higher because the thickness of the easy peel layer is equal to or less than the upper limit.
Here, the "thickness of the easy peel layer" means the thickness of the entire easy peel layer. means the thickness of

The ratio of the thickness of the easy peel layer to the thickness of the bottom material multilayer film is not particularly limited, but is preferably 5 to 40%. When the ratio is equal to or higher than the lower limit, the seal strength of the easy peel layer is moderately high. Easy peel property becomes higher because the said ratio is below the said upper limit.

<Oxygen barrier layer>
The oxygen barrier layer imparts an oxygen barrier property (in other words, a property of suppressing permeation of oxygen gas) to the multilayer film for bottom material.

The oxygen barrier layer in the multilayer film for bottom material preferably contains ethylene-vinyl alcohol copolymer (EVOH, also known as ethylene-vinyl acetate copolymer saponified product) or polyamide.

Examples of the polyamide include 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611-nylon, 612-nylon , 6T-nylon, 6I nylon, copolymer of 6-nylon and 66-nylon (nylon 6/66), copolymer of 6-nylon and 610-nylon, copolymer of 6-nylon and 611-nylon, 6-nylon and 12-nylon (nylon 6/12), 6-nylon and 612 nylon copolymer, 6-nylon and 6T-nylon copolymer, 6-nylon and 6I-nylon copolymer, 6-nylon and Copolymers of 66-nylon and 610-nylon, copolymers of 6-nylon, 66-nylon and 12-nylon (nylon 6/66/12), copolymers of 6-nylon, 66-nylon and 612-nylon, 66 - copolymer of nylon and 6T-nylon, copolymer of 66-nylon and 6I-nylon, copolymer of 6T-nylon and 6I-nylon, copolymer of 66-nylon, 6T-nylon and 6I-nylon, etc. .

In terms of heat resistance, mechanical strength, availability, etc., the polyamide is 6-nylon (herein sometimes abbreviated as "Ny6"), 12-nylon, 66-nylon , nylon 6/66, nylon 6/12 or nylon 6/66/12.

The polyamide contained in the oxygen barrier layer in the multilayer film for bottom material may be of only one type, or may be of two or more types. can be selected arbitrarily.

The oxygen barrier layer in the multilayer film for bottom material may contain only one or both of the ethylene-vinyl alcohol copolymer and the polyamide (that is, either one of the ethylene-vinyl alcohol copolymer and the polyamide or It may consist of both), and either one or both of the ethylene-vinyl alcohol copolymer and the polyamide, and components other than these (herein, may be referred to as "other components" ) (that is, it may consist of either one or both of an ethylene-vinyl alcohol copolymer and a polyamide, and the other components).

The other component contained in the oxygen barrier layer in the multilayer film for bottom material is not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin neither an ethylene-vinyl alcohol copolymer nor a polyamide.
Examples of the other components, which are non-resin components, include the same additives as the other components contained in the sealant layer 11 in the multilayer film 1 described above.

The other components contained in the oxygen barrier layer in the multilayer film for bottom material may be only one kind, or may be two or more kinds. can be selected arbitrarily according to

The ratio of the total content of the ethylene-vinyl alcohol copolymer and the polyamide to the total weight of the oxygen barrier layer in the multilayer film for bottom material is preferably 50 to 100% by weight, and 60 It is more preferably up to 100% by mass, and may be, for example, 70 to 100% by mass or 85 to 100% by mass.
The above ratio is usually the total content of the ethylene-vinyl alcohol copolymer and the polyamide (mass part) is the same as

The oxygen barrier layer in the multilayer film for bottom material may consist of one layer (single layer) or may consist of two or more layers. When the oxygen barrier layer is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the oxygen barrier layer in the multilayer film for bottom material is preferably 2 to 20 μm. When the thickness of the oxygen barrier layer is equal to or greater than the lower limit, the oxygen barrier property of the oxygen barrier layer becomes higher. When the thickness of the oxygen barrier layer is equal to or less than the upper limit, the oxygen barrier layer is prevented from being excessively thick.
Here, the "thickness of the oxygen barrier layer" means the thickness of the entire oxygen barrier layer. means the thickness of

Although the ratio of the thickness of the oxygen barrier layer to the thickness of the bottom material multilayer film is not particularly limited, it is preferably 5 to 15%. When the ratio is equal to or higher than the lower limit, the oxygen barrier property of the bottom material multilayer film becomes higher. When the ratio is equal to or less than the upper limit, excessive thickness of the oxygen barrier layer is suppressed.

<Anti-pinhole layer>
The anti-pinhole layer is a layer for protecting the structure of the multilayer film for bottom material, such as by suppressing the generation of pinholes in the multilayer film for bottom material.

The anti-pinhole layer in the multi-layer film for bottom material preferably contains polyolefin.
Examples of the polyolefin include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene catalyst linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and the like. of polyethylene; polypropylene and the like.

The pinhole-resistant layer in the multilayer film for bottom material may contain only polyolefin (that is, may consist of polyolefin), or may contain polyolefin and other components (in this specification, " may be referred to as "another component") (that is, it may consist of a polyolefin and the other component).

The other component contained in the pinhole-resistant layer in the multilayer film for bottom material is not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.
The other component, which is a resin component, is a resin other than polyolefin.
Examples of the other components, which are non-resin components, include the same additives as the other components contained in the sealant layer 11 in the multilayer film 1 described above.

The other component contained in the anti-pinhole layer in the multilayer film for bottom material may be of only one kind, or may be of two or more kinds. It can be arbitrarily selected according to the purpose.

The content of the polyolefin in the pinhole-resistant layer in the bottom multilayer film is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, with respect to the total mass of the pinhole-resistant layer. is more preferable, and may be, for example, 70 to 100% by mass or 85 to 100% by mass.
The ratio is usually the same as the ratio of the polyolefin content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming a pinhole-resistant layer for a bottom material, which will be described later. be.

The pinhole-resistant layer in the multilayer film for bottom material may consist of one layer (single layer) or may consist of two or more layers. When the anti-pinhole layer is composed of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the anti-pinhole layer in the multilayer film for bottom material is preferably 2 to 50 μm. When the thickness of the pinhole-resistant layer is equal to or greater than the lower limit, the pinhole-resistant layer has a higher protective ability. When the thickness of the pinhole-resistant layer is equal to or less than the upper limit, the pinhole-resistant layer is prevented from being excessively thick.
Here, the "thickness of the pinhole-resistant layer" means the thickness of the entire pinhole-resistant layer. means the total thickness of the layers of

Although the ratio of the thickness of the pinhole-resistant layer to the thickness of the bottom material multilayer film is not particularly limited, it is preferably 5 to 40%. When the ratio is equal to or higher than the lower limit, the pinhole resistance of the bottom material multilayer film becomes higher. When the ratio is equal to or less than the upper limit, it is possible to prevent the pinhole-resistant layer from becoming excessively thick.

<Adhesive layer>
The adhesive layer is a layer for adhering the multilayer film for bottom material to the foamed resin layer, and contains an adhesive.

The adhesive is preferably an adhesive resin, more preferably an ethylene-vinyl acetate copolymer resin.
The ethylene-vinyl acetate copolymer resin has a structural unit derived from ethylene and a structural unit derived from vinyl acetate, and may have other structural units other than these, It does not have to be.
Examples of preferred ethylene-vinyl acetate copolymer resins include partially saponified ethylene-vinyl acetate copolymers.

The adhesive layer in the multilayer film for bottom material may contain only an adhesive (that is, may consist of an adhesive), or may include an adhesive and other components (in the present specification, may be referred to as "another component") (that is, it may consist of an adhesive and the other component).

The adhesive contained in the adhesive layer in the multilayer film for bottom material may be of only one type, or may be of two or more types. can be selected arbitrarily.

The other component contained in the adhesive layer in the multilayer film for bottom material is not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.

The other component contained in the adhesive layer in the multilayer film for bottom material may be only one kind, or may be two or more kinds. It can be selected arbitrarily.

The content of the adhesive in the adhesive layer in the bottom material multilayer film may be, for example, 50 to 100% by mass with respect to the total mass of the adhesive layer.
The ratio is usually the same as the ratio of the adhesive content (parts by mass) to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an adhesive layer for a bottom material, which will be described later. .

The adhesive layer in the multi-layer film for bottom material may consist of one layer (single layer) or may consist of two or more layers. When the adhesive layer is composed of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the adhesive layer in the multilayer film for bottom material is preferably 2 to 40 μm. When the thickness of the adhesive layer is equal to or greater than the lower limit, the adhesive strength between the two layers to be adhered becomes higher. When the thickness of the adhesive layer is equal to or less than the upper limit value, excessive thickness of the adhesive layer is suppressed.
Here, the "thickness of the adhesive layer" means the thickness of the entire adhesive layer. means.

Although the ratio of the thickness of the adhesive layer to the thickness of the bottom material multilayer film is not particularly limited, it is preferably 5 to 40%. When the ratio is equal to or higher than the lower limit value, the adhesive strength of the two layers to be adhered becomes higher. When the ratio is equal to or less than the upper limit, excessive thickness of the adhesive layer is suppressed.

<First Intermediate Adhesive Layer, Second Intermediate Adhesive Layer>
The first intermediate adhesive layer and the second intermediate adhesive layer contain an adhesive.
The adhesive is preferably an adhesive resin.
Examples of the adhesive resin include polyolefin resins.
The polyolefin-based resin is a resin having a structural unit derived from an olefin, and may be a modified polyolefin such as an acid-modified polyolefin having an acidic group (eg, acid-modified polyethylene, acid-modified polypropylene).
Examples of polyolefin-based resins include ethylene-based copolymers, propylene-based copolymers, butene-based copolymers, modified products of these copolymers (in other words, modified copolymers), and the like.
The polyolefin-based resin is preferably a random copolymer, a graft copolymer, or a block copolymer from the viewpoint of further improving adhesiveness.

Examples of the ethylene-based copolymer include the ethylene-based copolymers described above as those contained in the easy peel layer, modified products thereof (modified copolymers), and the like.
Examples of the propylene-based copolymer include copolymers of propylene and a vinyl group-containing monomer, modified products thereof (modified copolymers), and the like. More specific examples of such propylene-based copolymers include maleic anhydride graft-modified linear low-density polypropylene and propylene-based thermoplastic elastomers.
Examples of the butene-based copolymer include copolymers of 1-butene and a vinyl group-containing monomer, copolymers of 2-butene and a vinyl group-containing monomer, and modified products of these copolymers (modified copolymers). coalescence) and the like.

The first intermediate adhesive layer and the second intermediate adhesive layer may contain only an adhesive (that is, may consist of an adhesive), or may contain an adhesive and other components (this specification In the literature, it may be referred to as "another component") (that is, it may consist of an adhesive and the other component).

The adhesives contained in the first intermediate adhesive layer and the second intermediate adhesive layer may be of only one type, or may be of two or more types. , can be arbitrarily selected according to the purpose.

The other components contained in the first intermediate adhesive layer and the second intermediate adhesive layer are not particularly limited and can be arbitrarily selected according to the purpose, and may be, for example, either a resin component or a non-resin component.

The other components contained in the first intermediate adhesive layer and the second intermediate adhesive layer may be only one kind, or may be two or more kinds, and in the case of two or more kinds, combinations and ratios thereof can be arbitrarily selected according to the purpose.

In the first intermediate adhesive layer in the bottom material multilayer film, the content of the adhesive may be, for example, 50 to 100% by mass with respect to the total mass of the first intermediate adhesive layer.
The ratio is usually the ratio of the content (parts by mass) of the adhesive to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming the first intermediate adhesive layer for the bottom material, which will be described later. are the same.
In the second intermediate adhesive layer in the bottom material multilayer film, the content of the adhesive may be, for example, 50 to 100% by mass with respect to the total mass of the second intermediate adhesive layer.
The ratio is usually the ratio of the content (parts by mass) of the adhesive to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming the second intermediate adhesive layer for the bottom material, which will be described later. are the same.

Each of the first intermediate adhesive layer and the second intermediate adhesive layer in the multilayer film for bottom material may consist of one layer (single layer), or may consist of two or more layers. good too. When the first intermediate adhesive layer or the second intermediate adhesive layer consists of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is particularly Not limited.

The thicknesses of the first intermediate adhesive layer and the second intermediate adhesive layer in the multilayer film for bottom material are preferably 2 to 15 μm independently. When the thicknesses of the first intermediate adhesive layer and the second intermediate adhesive layer are equal to or greater than the lower limit values, the adhesive strength of the two layers to be adhered becomes higher. Since the thicknesses of the first intermediate adhesive layer and the second intermediate adhesive layer are equal to or less than the upper limit value, excessive thicknesses of the first intermediate adhesive layer and the second intermediate adhesive layer are suppressed.
Here, the "thickness of the first intermediate adhesive layer" means the thickness of the entire first intermediate adhesive layer. means the total thickness of all the layers that make up the This is the same for the second intermediate adhesive layer.

The ratio of the thickness of the first intermediate adhesive layer and the second intermediate adhesive layer to the thickness of the bottom material multilayer film is not particularly limited, but is preferably 3 to 20%. When the ratio is equal to or higher than the lower limit value, the adhesive strength of the two layers to be adhered becomes higher. When the ratio is equal to or less than the upper limit, excessive thicknesses of the first intermediate adhesive layer and the second intermediate adhesive layer are suppressed.

<Other layers>
The multilayer film for a bottom material comprises the easy peel layer, the first intermediate adhesive layer, the oxygen barrier layer, the second intermediate adhesive layer, and the anti-pinhole layer within the range that does not impair the effects of the present invention. Other layers that are neither the layer nor the adhesive layer may be provided.

The type and arrangement position of the other layers in the multilayer film for bottom material are not particularly limited, and can be arbitrarily selected according to the purpose.

The other layers included in the bottom material multilayer film may be of only one type, or may be of two or more types. It can be selected arbitrarily.

Each type of the other layer in the multilayer film for bottom material may consist of one layer (single layer) or may consist of two or more layers. When the other layer is composed of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the other layers in the multilayer film for bottom material can be arbitrarily set according to the type thereof, and is not particularly limited.

When the multi-layer film for bottom material comprises the other layer, it may further comprise an intermediate adhesive layer for bonding the other layer to the other layer. In this case, the intermediate adhesive layer is , for example, the same as the first intermediate adhesive layer or the second intermediate adhesive layer described above.

The thickness of the non-foamed resin layer of the multilayer film for bottom material is not particularly limited, but is preferably 40 to 120 μm.

<<Manufacturing method of bottom material>>
The bottom material can be manufactured by a known method depending on its type.
For example, when the bottom material is a resin laminate including the foamed resin layer and the non-foamed resin layer, one surface of the foamed resin layer and one surface of the non-foamed resin layer (non-foamed resin When the layer is the multi-layer film for the base material, the base material can be produced by laminating together the adhesive layer in it by heat lamination. The heat lamination at this time may be performed by, for example, a melt pressure lamination method as described later in Examples, or may be performed by an extrusion lamination method.
Among the non-foamed resin layers, the multilayer film for the bottom material is formed in the same manner as in the case of the resin film (lid material) described above, except that the types of resins or resin compositions that are the forming materials of each layer are different, for example. can be manufactured.

Regardless of the manufacturing method, the resin composition, which is a material for forming any of the layers in the multilayer film for bottom material, contains the desired component (constituent material) of the layer to be formed. The type and content of the ingredients may be adjusted so as to contain the required amount. For example, the content ratio of the components that do not vaporize at room temperature in the resin composition is usually the same as the content ratio of the components in the layer formed from the resin composition.

As the resin composition for forming the easy peel layer in the multilayer film for bottom material (in this specification, it may be referred to as "composition for forming easy peel layer for bottom material"), for example, the polyolefin and , and optionally the other components.

Examples of the resin composition for forming the oxygen barrier layer in the bottom material multilayer film (which may be referred to herein as the "bottom material oxygen barrier layer-forming composition") include, for example, ethylene-vinyl Examples include those containing either one or both of an alcohol copolymer and a polyamide, and optionally the other components.

Examples of the resin composition for forming the pinhole-resistant layer in the bottom material multilayer film (which may be referred to herein as a "bottom material pinhole-resistant layer-forming composition") include, for example, Examples include those containing polyolefin and, if necessary, the other components described above.

A resin composition for forming an adhesive layer (in this specification, may be referred to as a "composition for forming an adhesive layer for a bottom material") in a multilayer film for a bottom material, forming a first intermediate adhesive layer (In this specification, it may be referred to as a "first intermediate adhesive layer forming composition for bottom material"), a resin composition for forming a second intermediate adhesive layer (in this specification, may be referred to as "the composition for forming the second intermediate adhesive layer for the bottom material") may include, for example, the adhesive and, if necessary, the other component mentioned.

<<One embodiment of raw meat skin pack package>>
FIG. 2 is a cross-sectional view schematically showing an example of the raw meat skin pack package of the present embodiment.
In the drawings after FIG. 2, the same constituent elements as those shown in already explained figures are given the same reference numerals as in the already explained figures, and detailed explanations thereof will be omitted.

A raw meat skin pack package 10 shown here is configured with a multilayer film (lid material) 1 and a bottom material 8 shown in FIG.
In addition, in FIG. 2, distinction of each layer in the multilayer film 1 is omitted.

In the raw meat skin pack package 10, the temperature at which the multilayer film (lid material) 1 shows a displacement of 2000 μm is 120° C. or higher in the thermomechanical analysis of the multilayer film (lid material) 1, or the gel fraction of the multilayer film (lid material) 1 is 30% or more.
In the raw meat skin pack package 10, the oxygen permeation amount of the multilayer film (lid material) 1 is 100 cc/(m ² ·day · atm) or less under the conditions of a temperature of 23 ° C. and a relative humidity of 60%. .
In the raw meat skin pack package 10, the displacement at a temperature of 100° C. is preferably 500 μm or less during the thermomechanical analysis of the multilayer film (lid material) 1 .
In the raw meat skin pack package 10, the multilayer film (lid material) 1 is preferably irradiated with electron beams at an absorbed dose of 13 to 300 kGy.

In the raw meat skin pack package 10, the oxygen permeation amount of the bottom material 8 is 300 cc/(m ² ·day·atm) or less under conditions of a temperature of 23° C. and a relative humidity of 60%.

When the raw meat skin pack package 10 is the test package, the _HI calculated using the raw meat skin pack package 10 is 30 to 90% by mass. Then, when this fresh meat skin pack package 10 was stored at 4°C in an air atmosphere, the number of coliform bacteria in the test meat in the unopened fresh meat skin pack package 10 after 14 days from the start of storage was 0 cfu. /g is preferred. In addition, the general viable cell count in the test meat in the unopened fresh meat skin pack package 10 after 14 days from the start of storage is preferably 1×10 ⁶ cfu/g or less.

Since the raw meat skin pack package 10 uses the multilayer film 1, it has excellent followability to the raw meat 9 which is the content.
In addition, since the fresh meat skin pack package 10 uses the multilayer film (lid material) 1 and the bottom material 8, the oxygen barrier property for the fresh meat 9 is high, and the storage period of the fresh meat 9 is longer than that of the conventional package. longer than the case.
In addition, the raw meat skin pack package 10 uses the multilayer film (lid material) 1 and the bottom material 8, so that the content of inosinic acid in the raw meat 9 during storage can be maintained at a moderately high level. , the raw meat can be preserved in a delicious state.

One surface 8a of the bottom material 8 (in this specification, sometimes referred to as the “first surface”) 8a is a sealing surface, and a part of the first surface 8a and the sealant layer in the multilayer film 1 A portion of the first surface 11a of 11 is in close contact with a seal. In FIG. 2, the portion where the first surface 8a of the bottom material 8 and the first surface 11a of the sealant layer 11 in the multilayer film 1 are in direct contact is the seal portion. As a result, a storage portion 10a is formed between the first surface 8a of the bottom material 8 and the first surface 11a of the sealant layer 11 . Raw meat 9 is hermetically sealed in the storage portion 10a.

When the bottom material 8 is the bottom material multilayer film, the first surface 8a of the bottom material 8 is the surface of the easy peel layer opposite to the oxygen barrier layer side.

In FIG. 2, there are some gaps between the raw meat 9 and the multilayer film 1 and between the raw meat 9 and the bottom material 8 in the storage part 10a of the raw meat skin pack package 10. , these gaps may not exist in the raw meat skin pack package 10 in which the raw meat 9 is stored.

The test package used for measuring the inosinic acid content I _t (eg, I ₁ , I ₇ ) corresponds to the raw meat skin pack package 10 shown here. The test meat in the test package corresponds to the raw meat 9 shown here.

The raw meat skin pack package of the present embodiment is not limited to the one described above, and part of the configuration may be changed, deleted, or added within the scope of the present invention.
For example, FIG. 2 shows a raw meat skin pack package 10 configured using the multilayer film 1 shown in FIG. It may be configured using

<<Manufacturing method for raw meat skin pack packaging>>
In the raw meat skin pack packaging body of the present embodiment, for example, raw meat is placed on the surface of the bottom material that is sealed with the lid material, and the surface of the bottom material and the raw meat are coated with these The lid material is covered from above, and the area between the bottom material and the lid material in which the raw meat is arranged is vacuumed to place the raw meat while the lid material is tightly fixed to the raw meat. It can be manufactured by heat-sealing the bottom material and the lid material in the areas that are not sealed.
The test packages can also be produced in the same manner.

Although the sealing temperature during heat sealing is not particularly limited, it is preferably 100 to 170°C. When the sealing temperature is equal to or higher than the lower limit, the seal strength is increased while maintaining easy peelability. When the sealing temperature is equal to or lower than the upper limit, it becomes easier to open the package.

The sealing time during heat sealing can be appropriately adjusted according to the sealing temperature, but is usually preferably 10 to 30 seconds. When the sealing time is equal to or longer than the lower limit, the seal strength is increased while maintaining easy peelability. When the sealing time is equal to or less than the upper limit, it becomes easier to open the package.

It is preferable that the pressure in the area where the raw meat is placed is 5000 Pa (50 mbar) or less due to vacuuming during heat sealing. When the pressure is equal to or less than the upper limit, a skin pack package having higher followability (adherence) to raw meat of the lid material and superior storage suitability can be obtained.

◎ Package As a package according to one embodiment of the present invention in which raw meat is skin-packed (in this specification, it may be referred to as a "package of the second embodiment"), a lid material and a bottom material wherein the lid member is made of a resin film, and the temperature at which the resin film exhibits a displacement of 2000 μm is 120° C. or higher, or the resin film has a gel fraction of 30% during thermomechanical analysis. above, and the oxygen permeation amount of the lid material under conditions of a temperature of 23° C. and a relative humidity of 60% is 100 cc/(m ² ·day · atm) or less, and a temperature of 23° C. and a relative humidity of 60%. The oxygen permeation amount of the bottom material under the above conditions is 300 cc/(m ² ·day · atm) or less, and the raw meat is cut from a sirloin part obtained from a slaughtered beef cattle, The raw meat is skin-packed using a lid material and a bottom material to prepare the package, the package is stored in an air atmosphere at 4 ° C., and one day after the package is produced. Measure the content I 1 of inosinic acid in the raw meat in the unopened package during storage, and measure the content I ₁ ' of inosinic acid in the raw meat in the unopened package during storage 7 days after the production of the package. When the inosinic acid content I ₇ ' of is measured, the following formula (F _I ')
(F _I ') HI '= _{I 7} '/I ₁ '×100
A packaging body having an inosinic acid retention rate H _I ' calculated from 30 to 90% by mass.

The lid material and the bottom material in the package of the second embodiment are the same as the lid material and the bottom material in the fresh meat skin pack package described above (the package of the first embodiment), respectively.
The package of the second embodiment is the same as the package of the first embodiment, except that a specific range of raw meat is skin-packed, and is processed in the same manner as the package of the first embodiment. can be manufactured.

The raw meat in the package of the second embodiment is not particularly limited as long as it is cut from a sirloin part obtained from a slaughtered beef cattle. For example, the raw meat includes the test meat in the package of the first embodiment.

The inosinic acid content I _t ' in the raw meat in the unopened package during storage t days (t is a number greater than 0) after the production of the package of the second embodiment is the measurement It can be measured by the same method as in the case of the above-mentioned It in the _package of the first embodiment, except that the target raw meat may be different. For example, I ₁ ′ and I ₇ ′ in the package of the second embodiment can be measured in the same manner as I ₁ and I ₇ in the package of the first embodiment, respectively.

The H _I ' in the package of the second embodiment is 30 to 90% by mass, and may be the same as or different from the H _I in the package of the first embodiment, for example.

In the package of the second embodiment, the content of inosinic acid in the raw meat is maintained at a moderately high level, and aging of the raw meat improves the palatability of the raw meat.

The package of the second embodiment is stored at 4°C in an air atmosphere, and the oleic acid content O ₁ in the raw meat in the unopened package during storage one day after the package is manufactured. ' was measured, and the content O ₇ ' of oleic acid in the raw meat in the unopened package during storage 7 days after the package was produced was measured by the following formula (F _O ')
(FO') _HO ' = _O7 '/ _O1 ' x ₁₀₀
The retention rate of oleic acid H 2 _O 2 calculated by may be 50 to 150% by mass. In the package of the second embodiment, when the oleic acid retention rate H _O ' is 50 to 150% by mass, the oleic acid content of raw meat during storage is maintained at a moderately high level, By aging the raw meat, the deliciousness of the raw meat is further improved.

The oleic acid content O _t ' in the raw meat in the unopened package during storage t days (t is a number greater than 0) after the package of the second embodiment was produced was measured It can be measured by the same method as the O _t in the package of the first embodiment, except that the target raw meat may be different. For example, the O ₁ ′ and O ₇ ′ in the package of the second embodiment can be measured in the same manner as the O ₁ and O ₇ in the package of the first embodiment, respectively.

The H 2 _O 2 ′ in the package of the second embodiment may be the same as or different from the H 2 _O in the package of the first embodiment, for example.

The package of the second embodiment is stored at 4°C in an air atmosphere, and the alanine content A ₁ ' in the raw meat in the unopened package during storage one day after the package is produced. was measured, and the alanine content A ₇ ' in the raw meat in the unopened package during storage 7 days after the package was produced was measured by the following formula (F _A ')
(F _A ') H _A ' = A ₇ '/A ₁ ' x 100
Alanine retention H _A ' calculated in may be 50 to 200% by mass. In the package of the second embodiment, when the alanine retention H _A is 50 to 200% by mass, the alanine content of the raw meat during storage is maintained at a moderately high level, and the raw meat is aged. The taste of raw meat is further improved by this.

The alanine content A _t ' in the raw meat in the unopened package during storage t days (t is a number greater than 0) after the production of the package of the second embodiment is the measurement target It can be measured by the same method as the above- _mentioned At in the package of the first embodiment, except that the raw meat may be different. For example, A ₁ ' and A ₇ ' in the package of the second embodiment can be measured by the same methods as A ₁ and A ₇ in the package of the first embodiment, respectively.

The H _A ' in the package of the second embodiment may be, for example, the same as or different from the H _A in the package of the first embodiment.

In the package of the second embodiment, at least the HI ' out of the _HI ', _HO ' and _HA ' _satisfies the above conditions, and the _HI ' and the _HO ' and either one or both of H _A ' preferably satisfy the above conditions, and it is more preferable that all of H _I ', H _O ' and H _A ' satisfy the above conditions. .

That is, as a preferred packaging body of the second embodiment, for example, a packaging body comprising a lid material and a bottom material, and raw meat is skin-packed, wherein the lid material is made of a resin film, and the resin film is At the time of thermomechanical analysis, the temperature at which the displacement of 2000 μm is exhibited is 120° C. or higher, or the gel fraction of the resin film is 30% or higher, the temperature is 23° C., and the relative humidity is 60%. The lid material has an oxygen permeation rate of 100 cc/(m ² ·day·atm) or less, and the bottom material has an oxygen permeation rate of 300 cc/(m ² ) under conditions of a temperature of 23°C and a relative humidity of 60%. · day · atm) or less, the raw meat is cut from a sirloin part obtained from a slaughtered beef cattle, and the raw meat is skin-packed using the lid material and the bottom material, The package is prepared, the package is stored at 4° C. in an air atmosphere, and the content of inosinic acid in the raw meat in the unopened package during storage one day after the package is prepared. The amount I ₁ ' was measured, and the content I ₇ ' of inosinic acid in the raw meat in the unopened package during storage seven days after the package was produced was measured according to the following formula (F _I ')
(F _I ') HI '= _{I 7} '/I ₁ '×100
The inosinic acid retention rate H _I ' calculated by is 30 to 90% by mass, and
One day after the production of the package, the oleic acid content O ₁ ' in the raw meat in the unopened package during storage was measured, and seven days after the production of the package, the unopened during storage. When the content O ₇ ' of oleic acid in the raw meat in the unsealed package is measured, the following formula (F _O ')
(FO') _HO ' = _O7 '/ _O1 ' x ₁₀₀
is 50 to ₁₅₀ % by mass, or
Measure the alanine content A ₁ ' in the raw meat in the unopened package during storage one day after production of the package, and unopened during storage 7 days after production of the package. When the alanine content A ₇ ' in the raw meat in the package of is measured, the following formula (F _A ')
(F _A ') H _A ' = A ₇ '/A ₁ ' x 100
The alanine retention rate H _A ' calculated by is 50 to 200% by mass.

A more preferable package of the second embodiment is, for example, a package including a lid material and a bottom material, in which fresh meat is skin-packed, the lid material is made of a resin film, and the resin film is heat-treated. The temperature at which the displacement of 2000 μm is exhibited at the time of mechanical analysis is 120° C. or higher, or the gel fraction of the resin film is 30% or higher, the temperature is 23° C., and the relative humidity is 60%. The oxygen permeation amount of the material is 100 cc/(m ² · day · atm) or less, and the oxygen permeation amount of the bottom material is 300 cc/(m ² · atm) under the conditions of a temperature of 23 ° C. and a relative humidity of 60%. day · atm), the raw meat is cut from a sirloin part obtained from a slaughtered beef cattle, and the raw meat is skin-packed using the lid material and the bottom material. A package is prepared, the package is stored at 4°C in an air atmosphere, and the content of inosinic acid in the raw meat in the unopened package during storage one day after the package is prepared I ₁ ' was measured, and the content _{I 7} ' of inosinic acid in the raw meat in the unopened package during storage 7 days after the preparation of the package was measured. )
(F _I ') HI '= _{I 7} '/I ₁ '×100
The inosinic acid retention rate H _I ' calculated by is 30 to 90% by mass, and
One day after the production of the package, the oleic acid content O ₁ ' in the raw meat in the unopened package during storage was measured, and seven days after the production of the package, the unopened during storage. When the content O ₇ ' of oleic acid in the raw meat in the unsealed package is measured, the following formula (F _O ')
(FO') _HO ' = _O7 '/ _O1 ' x ₁₀₀
is 50 to ₁₅₀ % by mass, and
Measure the alanine content A ₁ ' in the raw meat in the unopened package during storage one day after production of the package, and unopened during storage 7 days after production of the package. When the alanine content A ₇ ' in the raw meat in the package of is measured, the following formula (F _A ')
(F _A ') H _A ' = A ₇ '/A ₁ ' x 100
The alanine retention rate H _A ' calculated by is 50 to 200% by mass.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is by no means limited to the examples shown below.

[Example 1]
<<Manufacturing of multilayer film (lid material)>>
A multilayer film having the structure shown in FIG. 1 was manufactured by the procedure shown below.
That is, an ethylene-vinyl acetate copolymer (EVA, "V5714C" manufactured by Dow Mitsui Polychemicals, Inc.) was prepared as a resin constituting the sealant layer.
Low-density polyethylene (LDPE, density 0.922 g/cm ³ , "F222NH" manufactured by Ube Maruzen Polyethylene Co., Ltd.) was prepared as the resin constituting the outer layer.
A sodium-based ionomer (ION, "1601" manufactured by Mitsui DuPont Polychemicals Co., Ltd.) was prepared as a resin constituting the functional layer and the pinhole-resistant layer.
An ethylene-vinyl alcohol copolymer (EVOH, “GH3804B” manufactured by Nippon Gosei Co., Ltd.) was prepared as a resin constituting the oxygen barrier layer.
Maleic anhydride-modified polyethylene (modified PE, “NF536” manufactured by Mitsui Chemicals, Inc.) was prepared as an adhesive (adhesive resin) constituting the adhesive layers (first adhesive layer and second adhesive layer).

The temperature of the die is 250° C., and the EVA, the ION, the modified PE, the EVOH, the modified PE, the ION, and the LDPE are coextruded in this order (coextrusion T die method), a sealant layer (thickness 24 μm), a pinhole resistant layer (thickness 29 μm), an adhesive layer (first adhesive layer, thickness 8 μm), an oxygen barrier layer (thickness 10 μm), an adhesive layer (second A multilayer film (120 μm thick) was produced by laminating an adhesive layer (8 μm thick), a functional layer (17 μm thick) and an outer layer (24 μm thick) in this order in the thickness direction.

Next, the multilayer film obtained above was irradiated with an electron beam from the outside on the outer layer side under the conditions of an absorption dose of 175 kGy and an acceleration voltage of 160 kV.
As described above, the target electron beam-irradiated multilayer film (hereinafter sometimes referred to as “lid material (I)”) was obtained.

<<Evaluation of multilayer film (lid material)>>
<Temperature indicating displacement of 2000 μm, identification of displacement at temperature of 100° C.>
The electron beam-irradiated multilayer film (lid material (I)) obtained above was subjected to thermomechanical analysis using a thermal analysis device (manufactured by SII "EXSTAR6000") in accordance with JIS K 7196. rice field. Then, from the obtained thermomechanical analysis curve, the temperature (° C.) at which the displacement of 2000 μm and the displacement (μm) at the temperature of 100° C. were obtained. Table 1 shows the results.

<Measurement of gel fraction>
The gel fraction of the electron beam-irradiated multilayer film (lid (I)) obtained above was measured according to JIS K 6769.
That is, a test piece having a size of 3 cm x 3 cm (about 0.09 g) was cut out from the multilayer film, wrapped in a 400-mesh stainless steel wire mesh (100 g), and placed in xylene (18 mL) at 110°C. It was immersed for 24 hours.
Next, the test piece was taken out from the xylene together with the wire mesh, and vacuum-dried at 110° C. for 24 hours under a pressure of 1.7 kPa to obtain a dried test piece after immersion. The mass of the obtained dried product was measured, and the gel fraction (%) of the electron beam-irradiated multilayer film was determined. Table 1 shows the results.

<Measurement of oxygen permeation amount>
Regarding the electron beam irradiated multilayer film (lid material (I)) obtained above, the oxygen transmission rate ( cc/(m ² ·day · atm)) was measured. Table 1 shows the results.

<<Manufacturing of bottom material>>
<Manufacturing of multilayer film for bottom material>
A multilayer film for a bottom material was produced by the procedure described below.
That is, low-density polyethylene (LDPE, "L211" manufactured by Sumitomo Chemical Co., Ltd.) and polypropylene (PP, "FS2011DG2" manufactured by Sumitomo Chemical Co., Ltd.) were prepared as resins constituting the easy peel layer.
Metallocene-catalyzed linear low-density polyethylene (mLLDPE) (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared as a resin constituting the pinhole-resistant layer.
As a resin constituting the oxygen barrier layer, an ethylene-vinyl alcohol copolymer (EVOH, “J171B” manufactured by Kuraray Co., Ltd., density: 1180 kg/m ³ , MFR: 4.2 g/10 min) was prepared.
Acid-modified polypropylene (acid-modified PP, adhesive resin, "ADMER QF551" manufactured by Mitsui Chemicals, Inc.) was prepared as a resin constituting the first intermediate adhesive layer.
Acid-modified polyethylene (acid-modified PE, adhesive resin, "ADMER NF536" manufactured by Mitsui Chemicals, Inc.) was prepared as a resin constituting the second intermediate adhesive layer.
As the resin constituting the adhesive layer, an ethylene-vinyl acetate copolymer resin (EVA resin, adhesive resin, "Mersen (registered trademark) MX02D" manufactured by Tosoh Corporation) was prepared.

By mixing the LDPE (70 parts by mass) and the PP (30 parts by mass) at room temperature, a composition for forming an easy peel layer for a bottom material was produced.

The temperature of the die is set to 250° C., and the composition for forming an easy peel layer for a bottom material, the acid-modified PP, the EVOH, the acid-modified PE, the mLLDPE, and the EVA resin are added in this order. By co-extrusion (co-extrusion T die method), an easy peel layer (25.9 μm thick), a first intermediate adhesive layer (5.6 μm thick), an oxygen barrier layer (8.4 μm thick), a second 2 An intermediate adhesive layer (thickness 5.6 μm), a pinhole resistant layer (thickness 10.5 μm) and an adhesive layer (thickness 14 μm) are laminated in this order for the bottom material. A multilayer film (70 μm thick) was produced.

<Manufacturing of bottom material>
A foamed resin sheet (manufactured by Chuo Kagaku Co., Ltd., thickness 3000 μm) containing a polystyrene resin (PSP) foam was used, and on one surface thereof, the exposed surface of the adhesive layer of the multilayer film for bottom material obtained above was applied. A bottom material (hereinafter sometimes referred to as “bottom material (α)”) was obtained by laminating them together by heat lamination. The heat lamination of the foamed resin sheet and the multi-layer film for bottom material was performed by melt pressure lamination using a roll apparatus equipped with melt pressure rolls. The melt pressure bonding roll includes a heating roll and an opposing roll provided opposite to the heating roll. They were laminated together by melt-pressing the films at 180°C.

<<Evaluation of bottom material>>
<Measurement of oxygen permeation amount>
Regarding the bottom material (bottom material (α)) obtained above, the oxygen permeation amount (cc/(m ²・day·atm)) was measured. Table 2 shows the results.

<<Manufacturing raw meat skin pack package (test package)>>
A carcass was obtained from the slaughtered Japanese beef, and was primarily stored at 4°C for 2 days in an air atmosphere.
Next, a portion of meat was obtained from the dressed carcass after the primary storage, and this portion of meat (25 kg) was vacuum-packaged with an oxygen barrier film and secondary stored at 4° C. for 5 days in an air atmosphere. The oxygen barrier film comprises a polyethylene layer, an ethylene-vinyl acetate copolymer layer, a polyvinylidene chloride layer, an ethylene-vinyl acetate copolymer layer and an ultra-low density polyethylene layer laminated in this order in the thickness direction. Constructed (thickness 50 μm, size 30 cm × 50 cm), and oxygen permeation amount measured in accordance with JIS K 7126-2: 2006 is 10 cc / (m ² · day · atm) or less is. Vacuum packaging was performed by setting the sealing temperature at the time of heat sealing to 120° C., the sealing time to 3 seconds, and the pressure of the region where the partial meat is arranged to 30 mbar (3000 Pa).

Next, test meat of a sirloin part with a mass of 0.3 kg was cut out from the partial meat in the vacuum-packaged body after the secondary storage. Then, the sealant layer in the lid material (I) obtained above and the easy peel layer in the bottom material (α) are opposed to each other, and between the lid material (I) and the bottom material (α) The test meat is placed, and while the test meat is placed in a vacuum, the peripheral edges of the lid material (I) and the bottom material (α) are heat-sealed under the conditions of a sealing temperature of 150° C. and a sealing time of 10 seconds. By doing so, a test package, which is a skin pack package of test meat, was produced. When vacuuming, the pressure at the place where the test meat was placed was 30 mbar (3000 Pa). As the bottom material (α), one having a size of 20 cm×20 cm was used.
A plurality of the test packages were produced by the same procedure.

<<Evaluation of raw meat skin pack package (test package)>>
< _Calculation of HI>
These test packages were stored three times at 4° C. in an air atmosphere. _One day after the start of the tertiary storage, the test meat was taken out from the unopened test package, and the inosinic acid content I1 in the test meat was immediately measured. Further, the test meat was taken out from the unopened test package ₇ days after the start of the tertiary storage, and the inosinic acid content I7 in the test meat was immediately measured. Both _I1 and _I7 were measured by high performance liquid chromatography. Then, the retention rate H _I (% by mass) of inosinic acid in the test meat was calculated from the above formula (F _I ). Table 3 shows the results.

<Calculation of _HO >
_At the time of measuring I1 and _I7 above, the oleic acid contents _O1 and _O7 in the test meat were measured at the same time. Both _O1 and _O7 were measured by gas chromatography. Then, the retention rate H _O (% by mass) of oleic acid in the test meat was calculated from the formula (F _O ). Table 3 shows the results.

<Calculation of H _A >
At the time of measuring I ₁ and I ₇ above, the alanine contents A ₁ and A ₇ in the test meat were also measured at the same time. Both A ₁ and A ₇ were measured by an automatic amino acid analysis method. Then, the alanine retention rate H _A (% by mass) in the test meat was calculated according to the formula (F _A ). Table 3 shows the results.

<Measurement of general viable count>
After 14 days from the start of the tertiary storage, the test meat was taken out from the unopened test package, and the general viable cell count (cfu/g) in the test meat was immediately measured. Measurement of the general viable cell count was performed by the standard agar medium pour method. Table 3 shows the results.

<Measurement of coliform count>
At the time of the measurement of the general viable count, the number of coliforms in the test meat (the number of coliforms in the test meat 14 days after the start of tertiary storage) (cfu/g) was measured at the same time. Coliform counts were measured by the desoxycholate agar medium pour method. Table 3 shows the results.

<Followability evaluation>
The unopened test package 14 days after the start of the third storage was visually observed, and followability of the lid material to the test meat was evaluated according to the following criteria. Table 3 shows the results.
[Evaluation criteria]
A: There is no or very little lifting of the lid material from the test meat, and the followability is high.
B: Inferior to A, but the lid material is less lifted from the test meat, and the followability is good.
C: A lot of the lid material lifted from the test meat, and the followability was low.
D: The lid material does not follow the test meat.

<<Manufacturing and Evaluation of Multilayer Film (Lid Material), Manufacturing and Evaluation of Bottom Material, Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
[Example 2]
An electron beam-irradiated multilayer film (hereinafter referred to as “lid material (II)”) was prepared in the same manner as in Example 1, except that the absorbed dose was changed to 120 kGy instead of 175 kGy when the multilayer film was irradiated with an electron beam. ) was manufactured and evaluated.
A raw meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that this electron beam-irradiated multilayer film (lid material (II)) was used. .
The results are shown in Tables 1-3.

[Example 3]
An electron beam-irradiated multilayer film (hereinafter referred to as "lid material (III)") was prepared in the same manner as in Example 1, except that the absorbed dose was changed to 90 kGy instead of 175 kGy when the multilayer film was irradiated with an electron beam. ) was manufactured and evaluated.
A raw meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that this electron beam-irradiated multilayer film (lid material (III)) was used. .
The results are shown in Tables 1-3.

[Example 4]
An electron beam-irradiated multilayer film (hereinafter referred to as "lid material (IV)") was prepared in the same manner as in Example 1, except that the absorbed dose was changed to 15 kGy instead of 175 kGy when the multilayer film was irradiated with an electron beam. ) was manufactured and evaluated.
A raw meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that this electron beam-irradiated multilayer film (lid material (IV)) was used. .
The results are shown in Tables 1-3.

[Example 5]
<<Manufacturing and evaluation of bottom material>>
Examples except that 6-nylon (Ny6, “1030B2” manufactured by Ube Industries, Ltd., melting point 225° C.) was used as the resin constituting the oxygen barrier layer instead of the EVOH (“J171B” manufactured by Kuraray Co., Ltd.). A multilayer film for bottom material was produced in the same manner as in case 1.
The multilayer film for bottom material produced in this example includes an easy peel layer (25.9 μm thick), a first intermediate adhesive layer (5.6 μm thick), an oxygen barrier layer (8.4 μm thick), a second A multi-layered base material comprising an intermediate adhesive layer (thickness 5.6 μm), a pinhole resistant layer (thickness 10.5 μm) and an adhesive layer (thickness 14 μm) laminated in this order in the thickness direction. It is a film (70 μm thick).
Then, a bottom material (hereinafter sometimes referred to as "bottom material (β)") was produced and evaluated in the same manner as in Example 1 except that this multilayer film for bottom material was used. Table 2 shows the results.

<<Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
A raw meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that the bottom material (β) obtained above was used. Table 3 shows the results.

<<Manufacturing and Evaluation of Multilayer Film (Lid Material), Manufacturing and Evaluation of Bottom Material, Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
[Comparative Example 1]
A cover material (multilayer film not irradiated with electron beams, hereinafter sometimes referred to as "cover material (V)") was prepared in the same manner as in Example 1 except that the multilayer film was not irradiated with an electron beam. ) were manufactured and evaluated.
A fresh meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1 except that this electron beam non-irradiated multilayer film (lid material (V)) was used. .
The results are shown in Tables 1-3.

[Comparative Example 2]
<<Manufacturing and evaluation of bottom material>>
As the resin constituting the oxygen barrier layer, metallocene-catalyzed linear low-density polyethylene (mLLDPE, "4040FC" manufactured by Ube Maruzen Polyethylene Co., Ltd., melting point 126° C.) was used instead of the EVOH ("J171B" manufactured by Kuraray Co., Ltd.). A multilayer film for bottom material was produced in the same manner as in Example 1, except for the above points.
The multilayer film for bottom material produced in this comparative example includes an easy peel layer (thickness of 25.9 μm), a first intermediate adhesive layer (thickness of 5.6 μm), an oxygen barrier layer (thickness of 8.4 μm), a second A multi-layered base material comprising an intermediate adhesive layer (thickness 5.6 μm), a pinhole resistant layer (thickness 10.5 μm) and an adhesive layer (thickness 14 μm) laminated in this order in the thickness direction. It is a film (70 μm thick).
Then, a bottom material (hereinafter sometimes referred to as "bottom material (γ)") was produced and evaluated in the same manner as in Example 1 except that this multilayer film for bottom material was used. Table 2 shows the results.

<<Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
A fresh meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that the bottom material (γ) obtained above was used. Table 3 shows the results.

[Comparative Example 3]
<<Manufacturing and Evaluation of Multilayer Film (Lid Material)>>
As the resin constituting the oxygen barrier layer, 6-nylon (Ny6, "1030B2" manufactured by Ube Industries, Ltd., melting point 225 ° C.) was used instead of the EVOH ("GH3804B" manufactured by Nippon Gosei Co., Ltd.). In the same manner as in Example 1, an electron beam-irradiated multilayer film (hereinafter sometimes referred to as "lid material (VI)") was produced.
The electron beam-irradiated multilayer film (lid material (VI)) produced in this comparative example includes a sealant layer (24 μm thick), a pinhole-resistant layer (29 μm thick), an adhesive layer (first adhesive layer, thickness thickness 8 μm), oxygen barrier layer (thickness 10 μm), adhesive layer (second adhesive layer, thickness 8 μm), functional layer (thickness 17 μm), and outer layer (thickness 24 μm) in this order in the thickness direction. It was obtained by irradiating an electron beam from outside on the outer layer side of a laminated multilayer film (thickness: 120 μm) under conditions of an absorption dose of 175 kGy and an acceleration voltage of 160 kV.
Then, the electron beam-irradiated multilayer film (lid (VI)) was evaluated in the same manner as in Example 1. Table 1 shows the results.

<<Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
A raw meat skin pack package (test package) was produced and evaluated in the same manner as in Example 1, except that the lid material (VI) obtained above was used. Table 3 shows the results.

<<Manufacturing and Evaluation of Fresh Meat Skin Pack Packaging>>
[Comparative Example 4]
Using test meat (0.3 kg) obtained in the same manner as in Example 1, the test meat was placed on a PSP tray ("FLB" manufactured by FP Corporation). Next, the test meat was covered with a resin film (“Diawrap” manufactured by Mitsubishi Chemical Corporation) to prepare a tray wrap package, which was used as a test package.
A plurality of the test packages were produced by the same procedure.

Then, this test package (raw meat skin pack package) was evaluated in the same manner as in Example 1. Table 3 shows the results.

As is clear from the above results, in Examples ₁ to 5, the inosinic acid retention rate HI in the skin-packed raw meat (test meat in the test package) was 40 to 63% by mass. The umami of the raw meat was maintained during storage of the raw meat.
Furthermore, in Examples 1 to 5, 14 days after the start of tertiary storage, the number of general viable bacteria in raw meat was 6.2×10 ⁵ cfu/g or less (1.2×10 ⁵ to 6.2×10 ⁵ cfu/g), was suppressed to a low level, and had a coliform count of 0 (coliform not detected).
As described above, the skin pack packages of Examples 1 to 5 matured the raw meat to improve its palatability, and furthermore, made it possible to extend the storage period of the raw meat more than conventionally.
In the skin pack packages of Examples 1 to 5, the oxygen permeation amount of the lid material was 6 cc/(m ² ·day·atm), and the oxygen permeation amount of the bottom material was 250 cc/(m ² ·day · atm). atm) or less (2 to 250 cc/(m ² ·day · atm)).

In the skin pack packages of Examples 1 to 5, the followability of the lid material to the raw meat was good, and they had desirable properties as skin pack packages. Among them, in the skin pack packages of Examples 1 to 3 and 5, the conformability of the lid material to raw meat was particularly excellent.
In the lid materials of Examples 1 to 5, the absorbed dose is 15 kGy or more (15 to 175 kGy), the temperature at which the displacement of 2000 μm is exhibited during the thermomechanical analysis is 125° C. or more (125 to 185° C.), During the thermomechanical analysis, the displacement at a temperature of 100° C. was 320 μm or less (62-320 μm), and the gel fraction was 35% or more (35-78%). Among them, in the lid materials of Examples 1 to 3 and 5, the absorbed dose is 90 kGy or more (90 to 175 kGy), and the temperature at which the displacement of 2000 μm is exhibited during the thermomechanical analysis is 135° C. or more (135 to 185 ° C.), the displacement at a temperature of 100° C. during the thermomechanical analysis was 120 μm or less (62 to 120 μm), and the gel fraction was 60% or more (60 to 78%).

In Examples 1 to 5, the retention rate of _oleic acid in skin-packed raw meat (test meat in the test package) was 100 to 130% by mass, and raw meat storage resulted in The juiciness was moderately high.
Furthermore, in Examples 1 to 5, the alanine retention rate H _A in skin-packed raw meat (test meat in the test package) was 80 to 130% by mass, and the sweetness of raw meat during storage of raw meat was maintained.
As described above, the skin pack packages of Examples 1 to 5 allowed the raw meat to mature and significantly improved its palatability.

On the other hand, in the skin pack package of Comparative Example 1, the followability of the lid material to the raw meat was low, and it did not have desirable properties as a skin pack package.
The lid material (multilayer film) of Comparative Example 1 was not irradiated with an electron beam. The displacement at °C was large and the gel fraction was low.

In Comparative Example 2, the retention rate HI of _inosinic acid in skin-packed raw meat (test meat in the test package) was excessively low, and the umami of the raw meat was not maintained during storage.
Furthermore, in Comparative Example 2, 14 days after the start of tertiary storage, the number of general viable bacteria in the raw meat was at a high level, and the raw meat was no longer suitable for eating.
As described above, the skin pack package of Comparative Example 2 could not improve the palatability of the raw meat by aging the raw meat, and could not extend the storage period of the raw meat.
In the skin pack package of Comparative Example 2, the oxygen permeation amount of the bottom material was 500 cc/(m ² ·day · atm), which was large.

Also in Comparative Example 3, the retention rate HI of _inosinic acid in the skin-packed raw meat (test meat in the test package) was excessively low, and the umami of the raw meat was not maintained during storage.
Furthermore, in Comparative Example 3, 14 days after the start of tertiary storage, the number of general viable bacteria in the raw meat was at a high level, and the raw meat was no longer suitable for eating.
As described above, the skin pack package of Comparative Example 3 also failed to improve the palatability of the raw meat by aging the raw meat, and also failed to extend the storage period of the raw meat.
In the skin pack package of Comparative Example 3, the oxygen permeation amount of the lid material was 120 cc/(m ² ·day·atm), which was large.

In Comparative Example 4, the retention rate HI of _inosinic acid in skin-packed raw meat (test meat in the test package) was excessively low, and the umami of the raw meat was not maintained during storage.
Furthermore, in Comparative Example 4, 7 days after the start of tertiary storage, the number of general viable bacteria in the raw meat was already higher than 1.0 × 10 ⁶ cfu / g, which was a high level, and the raw meat was It had become inedible. Therefore, in Comparative Example 4, the number of general viable bacteria (cfu/g) and the number of coliform bacteria (cfu/g) in the test meat 14 days after the start of tertiary storage were not measured, and the lid material was applied to the test meat. Followability was also not evaluated.

In Comparative Examples 2 to 4, the alanine retention rate H _A in skin-packed raw meat (test meat in the test package) was excessively low, and the oleic acid retention rate H _O was excessive. was expensive.

INDUSTRIAL APPLICABILITY The present invention can be used as a package for aging raw meat, improving its palatability, and extending the storage period of raw meat.

1 Multilayer film (lid material)
DESCRIPTION OF SYMBOLS 11... Sealant layer 12... Outer layer 13... Functional layer 14... Oxygen barrier layer 10... Fresh meat skin pack package (test package)
8 ... Bottom material 9 ... Raw meat (test meat)

Claims (4)

A method for manufacturing a package including a lid material and a bottom material and skin-packed raw meat,
The lid material is made of a resin film,
The bottom material comprises a foamed resin layer and a non-foamed resin layer provided on the foamed resin layer,
The foamed resin layer contains a polystyrene-based resin foam,
The non-foamed resin layer is composed of an easy peel layer, an oxygen barrier layer, a pinhole resistant layer, and an adhesive layer laminated in this order in the thickness direction,
In the bottom material, the non-foamed resin layer is adhered to the foamed resin layer by the adhesive layer,
The easy peel layer in the non-foamed resin layer contains an incompatible ethylene-based polymer and a propylene-based polymer,
the oxygen barrier layer in the non-foamed resin layer contains an ethylene-vinyl alcohol copolymer or polyamide,
The pinhole-resistant layer in the non-foamed resin layer contains polyethylene,
The adhesive layer in the non-foamed resin layer contains an ethylene-vinyl acetate copolymer resin as an adhesive,
The temperature at which the resin film exhibits a displacement of 2000 μm is 120° C. or higher, or the gel fraction of the resin film is 30% or higher, in a thermomechanical analysis of the resin film in accordance with JIS K 7196.
The oxygen permeation amount of the lid material under conditions of a temperature of 23° C. and a relative humidity of 60% is 100 cc/(m ² ·day · atm) or less,
Under conditions of a temperature of 23° C. and a relative humidity of 60%, the oxygen permeation amount of the bottom material is 300 cc/(m ² ·day · atm) or less,
The raw meat is the carcass obtained from a slaughtered edible beef cattle, which is primarily stored at 4 ° C. for 2 days in an air atmosphere, and the partial meat obtained from the carcass after the primary storage has an oxygen transmission rate of 10 cc / ( m ² · day · atm) or less vacuum packed with an oxygen barrier film, secondary storage at 4 ° C. for 5 days in an air atmosphere, cut out from the partial meat after secondary storage,
Using the lid material and the bottom material, the raw meat is skin-packed to prepare the package, and the package is stored at 4 ° C. in an air atmosphere, and one day after the package is produced. Measure the inosinic acid content I ₁ ' in the raw meat in the unopened package during storage, and measure the raw meat in the unopened package during storage 7 days after the package is produced. When measuring the content I ₇ ' of inosinic acid in the following formula (F _I ')
(F _I ') HI '= _{I 7} '/I ₁ '×100
The inosinic acid retention rate H _I ' calculated by is 30 to 90% by mass,
In the manufacturing method, the raw meat is placed on the surface of the bottom material that is to be sealed with the lid material, and the surface of the bottom material and the raw meat are placed on the surface of the bottom material without causing new microorganisms to adhere to the raw meat. Then, the lid material is covered from the top of these, and the area between the bottom material and the lid material where the raw meat is arranged is vacuumed, so that the lid material is tightly fixed to the raw meat. 3. A method for producing a package, wherein the bottom member and the lid member are heat-sealed in a region where the raw meat is not arranged, thereby skin-packing the raw meat to obtain the package. 2. The method for manufacturing a package according to claim 1, wherein the resin film is irradiated with an electron beam under the condition of an absorbed dose of 13 to 300 kGy. 3. The method for manufacturing a package according to claim 1, wherein displacement at a temperature of 100[deg.] C. is 500 [mu]m or less during said thermomechanical analysis of said resin film. The resin film is
an outer layer comprising polyethylene;
a functional layer comprising an ionomer and adjacent to the outer layer;
an oxygen barrier layer;
The method for producing a package according to any one of claims 1 to 3, which is a multilayer film comprising a sealant layer containing an ethylene-vinyl acetate copolymer.

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