JPH0479834B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention provides oxygen barrier properties suitable for tightly packaging meat, poultry, fish, ham, sausage, etc. to prevent dripping and maintain freshness. Regarding superior heat shrink laminate packaging materials. [Prior Art] Generally, in order to maintain freshness, meat is often packaged tightly with a heat-shrinkable flexible thermoplastic resin film before being sold on the market. Recently, even more
Heat-shrinkable laminate films having an oxygen barrier layer such as ethylene-vinyl acetate copolymer (EVA) have come into use, blocking oxygen and extending their freshness period. [Problem to be solved by the invention] However, there are differences in the adhesion between the resin film and the meat depending on the type of meat, freshness, blend of oils and fats, etc., and when the adhesion is low, Drips are more likely to separate and flow out, accumulating between the resin film and the meat, which not only significantly reduces the commercial value, but also has weak resistance to bacterial contamination and is prone to spoilage. Furthermore, even if the adhesion is strong, it is inevitable that drips will occur over time. As a result of intensive studies to solve the above problems, the inventors of the present invention found that the cause of drips is that bound water and free water separate and flow out due to changes in water retention capacity due to protein deterioration and tissue destruction. Since this occurs between the film and the meat and promotes spoilage, we thought that in order to prevent the occurrence of drips, it would be best to provide the resin film with a factor similar to the one that improves the water retention properties of proteins. The present invention has been made based on the above idea, and an object of the present invention is to provide a heat-shrinkable laminate packaging material for meat that absorbs drips that occur when meat is tightly packaged, and does not change the adhesion of the resin film. With the goal. [Means for Solving the Problems] In order to achieve the above object, the heat-shrinkable laminated packaging material for meat of the present invention combines a polymeric water absorbing agent with two sheets of water permeable sheets carrying a moisture conditioning agent. This is further sandwiched between a heat-shrinkable laminate film having an oxygen barrier layer and a water-permeable film. [Function] Since the heat-shrinkable laminate packaging material for meat of the present invention has the above-described structure, the drips generated from the tightly packaged meat are directly exposed to the air by the polymer absorbent. Since it is removed without touching it, there is almost no oxidation caused by oxygen, and the action of microorganisms is suppressed together with the heating that occurs when the resin film is heat-shrinked. Furthermore, the humidity control agent lowers the atmospheric humidity to the meat level. Suitable, relative humidity is maintained at 78-98%. [Example] The polymeric water-absorbing agent used in the present invention includes polymerizable monomers that are water-soluble in polysaccharides such as starch and cellulose, or that become water-soluble by hydrolysis, such as (meth)acrylic acid and (meth)acrylic acid. acid ester,
A hydrophilic polymer obtained by graft polymerization of (meth)acrylic acid amide, (meth)acrylonitrile, maleic acid, etc., or oligomers or cooligomers thereof, and hydrolyzed as necessary, is tertiary-polymerized using a cross-linking agent. These include those that are originally polymerized, and those that are three-dimensionally polymerized using a crosslinking agent from hydrophilic polymers such as polyethylene oxide, polypropylene oxide, polyvinylpyrrolidone, sulfonated polyethylene, and poly(meth)acrylate. Commercially available products include PX-402A (manufactured by Showa Denko Co., Ltd.), Sunwet IM-300 (manufactured by Sanyo Chemical Industries, Ltd.), and Aqua Keep 10SH (manufactured by Tetsuko Kagaku Kogyo Co., Ltd.). Examples of the crosslinking agent include di- or tri-(meth)acrylic acid esters of polyols such as ethylene glycol, unsaturated polyesters obtained by reacting polyols with unsaturated acids such as maleic acid, and allylated starches. , allylated cellulose, and the like. In addition, as a humidity conditioner, ethylene glycol,
Polyhydric alcohols such as propylene glycol, diethylene glycol monoethyl ether, 1,3-butylene glycol, and glycerin; low polymers of polyhydric alcohols such as polypropylene glycol, polyethylene glycol, and polyglycerin; and sugars such as xylitol, sorbitol, and maltitol. Examples include alcohol and aqueous solutions of hygroscopic polymeric substances such as methylcellulose and carboxymethylcellulose. In other words, any liquid that is itself liquid or an aqueous solution at room temperature, a hygroscopic liquid that absorbs moisture in a gaseous body, and that has a humidity control mechanism may be used. In particular, glycols that may come into contact with food may be used. , or glycerin are preferred. The sheet-like water-permeable material may be any material that holds a polymeric water-absorbing agent in between and impregnates and supports a water-permeable liquid humidity control agent, such as paper, pulp, etc.
Examples include cloth, nonwoven fabric, and the like. In addition, two sheets of water-permeable material supporting the above-mentioned humidity conditioning agent and sandwiching a polymeric water-absorbing agent,
The water-permeable film sandwiched between the heat-shrinkable laminate film having an oxygen barrier layer and the heat-shrinkable laminate film may be a sufficiently fine non-woven fabric made of a thermoplastic material, or a thermoplastic film made water-impermeable may be irradiated with electrons, etc. or a thermoplastic film that has been foamed to have fine communication holes during film manufacturing, or an inorganic material,
A material in which microscopic pores are formed by adding a nucleating agent with a high melting point and then stretching the material can be used as appropriate. However, since this water-permeable film comes into direct contact with meat, paper, pulp materials, etc. that carry water are permeable, but they easily release the water carried by external pressure. It is not preferable because the heat sealability is weak. Furthermore, as a heat-shrinkable laminate film having an oxygen barrier layer, an oxygen barrier layer containing a copolymer of vinylidene chloride and vinyl chloride, a crosslinked ethylene-vinyl acetate copolymer layer and an uncrosslinked ethylene-acetic acid copolymer layer are used. A heat-shrinkable laminate film provided between vinyl copolymer layers or an oxygen barrier layer containing hydrolyzed ethylene-vinyl acetate copolymer (EVA) sandwiched between cross-linked polyolefin polymers. A transparent laminate film is known (USP3741258, Japanese Unexamined Patent Application Publication No. 1983-1999).
43889), and their heat shrinkage rate is also sufficient for tight packaging of items to be packaged. However, vinylidene chloride needs to contain a plasticizer and a heat stabilizer, which not only impede oxygen barrier properties but also pose a risk of contaminating packaged foods. Therefore, in the present invention
It is preferable to use an EVA resin layer and a heat-shrinkable laminate film made of crosslinked polyolefin or the like. To make a heat-shrinkable laminated packaging material for meat using the above-mentioned materials, first, as shown in Fig. 1, a polymer absorbent 1 is sandwiched between sheet-like water-permeable materials 2 such as paper; A moisture-absorbing layer 4 is formed by supporting a moisture-controlling substance 3 such as glycerin on a sheet-like water-permeable substance 2. This is sandwiched between a water-permeable film 5 made of a nonwoven fabric made of a thermoplastic material, and a heat-shrinkable laminate film (hereinafter referred to as heat-shrinkable film) 6 having an oxygen barrier layer, and the peripheral edges are heat-sealed. Heat-shrinkable laminate packaging material for meat (hereinafter referred to as packaging material) 7
is created. Therefore, the packaging material 7 having the above structure
The peripheries of the water-permeable film 5 and the heat-shrinkable film 6 are firmly heat-sealed, and the periphery of the water-absorbing layer 4 is locked. The surface of the film 6 is free. The above-mentioned packaging material 7 is used in the form of a bag with the water-permeable film 5 as the inner surface. When meat is placed in this bag and tightly packaged, the generated drips are absorbed and removed by the polymer absorbent 1, and when the atmospheric humidity becomes dry, the humidity conditioner 3 releases moisture to control the humidity. Therefore, meat is kept at a constant atmospheric humidity. Example 1 7.0 g of a polymeric absorbent made of cross-linked sodium polyacrylate was sandwiched between two sheets of water-absorbing paper measuring 40 cm x 30 cm, and a water absorbing layer in which 11 g of glycerin was supported on the paper was mixed with a polypropylene nonwoven fabric and Packaging material sandwiched between EVA heat shrinkable films,
A bag measuring 20 cm x 30 cm was produced by folding the bag in half with the nonwoven fabric inside. Put 1 kg of block-shaped beef in this bag and heat it to 85℃.
When shrink-packed beef was subjected to shrink-packing for 5 seconds, shrink-wrapped beef with good adhesion was obtained. Example 2, Comparative Example 1 Beef that was shrink-wrapped in the same manner as in Example 1, and beef that was shrink-wrapped by putting 1 kg of beef into a 20 cm x 30 cm bag made of EVA laminated shrink film. , each 1℃
After leaving it for 12 days, its quality was evaluated. The results are shown in Table 1.

[Table] Example 3, Comparative Example 2 Beef packaged in the same manner as in Example 2 and Comparative Example 1 was stored frozen at -20°C for 10 days, then thawed over 3 days. The quality was evaluated. The results are shown in Table 2.

〔Effect of the invention〕

As described above, the heat-shrinkable laminate packaging material for meat according to the present invention can be stored for a long period of time without impairing the freshness of meat, thereby extending its distribution period in the market, and especially for raw materials in cold chains. Since the yield is improved, it is highly economical and greatly contributes to the distribution system.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the heat-shrinkable laminate packaging material for meat according to the present invention. DESCRIPTION OF SYMBOLS 1...Polymer absorbent, 2...Sheet-like water permeable material, 3...Moisture conditioner, 4...Moisture absorbing layer, 5...Water permeable film, 6...Heat shrinkable laminate film having an oxygen barrier layer (Heat shrink film), 7...
...Heat-shrink laminate packaging material (packaging material) for meat.

Claims (1)

[Claims] 1. A polymeric water absorbing agent is sandwiched between two sheets of water permeable material carrying a humidity conditioning agent, which are further sandwiched between a heat-shrinkable laminate film having an oxygen barrier layer and a water permeable film. A heat-shrinkable laminated packaging material for meat that is characterized by: