JPH05168398A - Packaging bag for keeping freshness of fruit and vegetable - Google Patents

Abstract

PURPOSE:To provide the subject articles which can keep fruits and vegetables fresh for a long period of time where the bags or pouches are perforated in a specified size, thus the gas composition in the bags or pouches is led to its optimal one for maintaining the freshness, when the fruits and vegetables are packed. CONSTITUTION:The objective bags or pouches are perforated so that the total perforated area reaches 0.4 to 4mm<2>/kg based on the weight of the vegetable and the ratio of diameter/thickness becomes 3 to 20. The diameter of the perforation is preferably 0.1 to 0.5mm. The material for the bags or pouches is preferably polypropylene, high-density polyethylene or the like and said resin preferably contains a nonionic substituent such as sorbitol monostearate. The perforation is formed by means of carbon dioxide laser or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freshness-maintaining packaging bag for fruits and vegetables, which is said to be highly respirable and transpiration after harvesting and difficult to keep fresh, and which is effective in the high temperature season from spring to summer.

[0002]

2. Description of the Related Art In recent years, many of the fruits and vegetables have been shifting from open-field cultivation to systematic multi-faceted and multi-faceted cultivation by cultivating horticultural facilities. A large amount of fruits and vegetables are harvested within a predetermined period. Often has to be wrapped. Also, even for fruits and vegetables that are mainly cultivated in the open field, the harvest time is fixed, so a large amount of harvested products must be packaged and shipped within a short period of time. The most important issue in the distribution process before crossing is how to maintain the freshness at the time of harvest.

The most effective means for maintaining the freshness of fruits and vegetables is to control the gas (mainly oxygen, nitrogen, carbon dioxide) in the storage atmosphere to a specific composition, that is, CA (= Controlled Atmosphere). ) It is a condition. This method has been studied by many people for a long time, and the optimum CA condition is defined for each kind of fruits and vegetables (Table 1). Large-scale storage devices for storing under CA conditions are actually sold, but they are not widely used by ordinary farmers due to the high cost. Therefore, researches for improving containers and packaging bags that can be stored more easily under CA conditions are being actively conducted. For example, JP-A-62-2350
In Japanese Patent Laid-Open No. 88 and Japanese Patent Laid-Open No. 1-309621, a container in which oxygen and carbon dioxide are controlled to flow in and out is shown by having a microporous gas-permeable panel in a part of the substantially gas-impermeable container. Has been done. Also, JP-A-56-133
No. 61, JP-A-61-216640 and JP-A-63-102634 disclose a packaging bag which uses a film having a large gas permeability to bring the gas composition in the bag close to the CA condition.

[Table 1]

[0005]

However, even though the materials used so far have no problem when used in low temperature conditions, in the case of fruits and vegetables whose breathing volume remarkably increases with increasing temperature, such as broccoli. Even polybutadiene, which is commonly used as a plastic material with high gas permeability, lacks gas permeability, and the oxygen concentration in the bag becomes too low, resulting in suffocation or too high a carbon dioxide concentration. There were problems such as abnormal physiological activities.

Therefore, as a method of increasing the gas permeability of the entire film, it is possible to physically form an opening in a part of the film. By adjusting the size and number of the openings, that is, the area of the openings, it is possible to obtain a high gas permeability that cannot be achieved by the film alone.

For example, as disclosed in JP-A-54-40793 and JP-A-63-119647, a bag having a part of an opening is devised, but the opening area is too large (that is, The gas permeability is too large) and the hole diameter is too large, so that the composition of the gas cannot be adjusted due to the influence of the surrounding air flow, which is not satisfactory. On the contrary, for example, in Japanese Patent Application Laid-Open No. 2-85181, since the hole diameter is too small and the hole is closed by the water in the bag, there is a risk that the required gas permeability cannot be obtained and the gas adjusting function is not sufficiently exerted. It was

An object of the present invention is to provide a packaging bag for keeping freshness, which exhibits oxygen and carbon dioxide permeability, which can lead to a CA condition suitable for physiological action of fruits and vegetables.

[0009]

[Means for Solving the Problems] The present inventors have conducted research on packaging bags for keeping freshness of fruits and vegetables, which are said to be difficult to store. As a result, it was found that the gas composition in the bag in which the fruits and vegetables are packaged can be brought to CA conditions by providing an opening of a specific size in a part or the whole surface of the packaging bag for keeping freshness. It came to completion.

That is, the present invention is
The bag has a total opening area of 0.4 to 4.0 mm ² / kg, and 3 <hole diameter /
A packaging bag for keeping freshness of fruits and vegetables, which is characterized in that an opening is provided in a range of thickness <20, and fruits and vegetables using the same.
The present invention relates to a method of maintaining freshness of fruits and vegetables which is packaged so that the ratio of the air volume in the bag to the volume of fruits and vegetables is 1 or more and 3 or less.

The following is a detailed description of the invention. According to the present invention, in order to obtain oxygen and carbon dioxide permeation rates that can lead to CA conditions, the total opening area is 0.4 to 4.0 mm ² / based on the weight of fruits and vegetables to be packed in a bag to be hermetically packed.
Open holes must be provided in kg and within the range of 3 <pore diameter / thickness <20.

That is, when the total open area is less than 0.4 mm ² / kg with respect to the weight of fruits and vegetables to be packaged, oxygen is consumed due to active breathing of fruits and vegetables, and the oxygen concentration in the bag becomes insufficient, Breathing, which is the minimum required to maintain vitality, is impaired, leading to a decrease in freshness. At the same time, since the carbon dioxide concentration becomes excessive, a physiological disorder occurs and an offensive odor is easily generated. On the other hand, when the total open area exceeds 4.0 mm ² / kg with respect to the weight of fruits and vegetables to be packaged, the oxygen concentration in the bag cannot be lowered until breathing can be suppressed and aging progresses. At the same time, the carbon dioxide concentration becomes too low, and the anti-corruption effect and the respiratory depression effect cannot be effectively exerted.

Further, when the fruits and vegetables are packed in a bag, a large amount of water is generated in the bag due to the respiration and transpiration of the fruits and vegetables. At this time, the smaller the opening hole diameter, the thicker the film thickness, the more the opening. The holes are more likely to be blocked by the passing water drops. Therefore, in order to prevent the openings from being blocked by water droplets, the condition of 3 <pore diameter / thickness <20 must be satisfied.
In other words, when the "pore size / thickness" is smaller than 3, the water pores are blocked by the water film, so that the gas permeability becomes lower than that of the design, and when the "pore size / thickness" becomes larger than 20, diffusion is caused by diffusion. In addition to gas exchange, the influence of external air flow (wind) will appear, so the gas permeability will be greater than the design,
After all, accurate gas adjustment cannot be done. At this time, the pore size is preferably 0.1 to 0.5 mm.

Further, in the resin constituting the packaging bag,
It is preferable to add 0.2 to 2.0% by weight of a nonionic surfactant. When the fruits and vegetables are packaged, a large amount of water drops adhere to the inner surface of the bag due to the transpiration effect of the fruits and vegetables. This not only impairs the appearance as a product, but also causes microorganisms to propagate in the portion in contact with the fruits and vegetables, causing putrefaction. Therefore, it is necessary to add a nonionic surfactant to the resin to impart antifogging property. Examples of the nonionic surfactant used at this time include sorbitan monostearate, sorbitan monopalmitate, and sorbitan fatty acid ester surfactants such as sorbitan monolaurate,
Glycerin fatty acid ester surfactants such as glycerin monostearate, glycerin monolaurate, glycerin monopalmitate, glycerin monolaurate, diglycerin dilaurate, triglycerin monostearate, polyethylene glycol monopalmitate,
Examples thereof include polyethylene glycol-based surfactants such as polyethylene glycol monostearate, alkylene oxide adducts of alkylphenols, and esters of sorbitan / glycerin condensates with organic acids.

Further, by packaging the head space ratio (ratio of the air volume in the bag to the volume of fruits and vegetables) to be 1 or more and 3 or less, the CA condition can be quickly prepared. After packaging, in the steady state, the gas concentration in the bag approaches the CA condition regardless of the headspace ratio, but when the headspace ratio is less than 1, the CA condition where the fruits and vegetables are placed is easily changed and becomes unstable. On the contrary, when the head space ratio becomes larger than 3, it takes time to reach the CA condition. CA as quickly as possible by reducing the head space
Creating conditions is important in preventing the freshness of fruits and vegetables, especially in the early stages.

Since the packaging bag has a very high gas permeability, it is more effective for fruits and vegetables which are hard to breathe and are difficult to keep fresh. Broccoli is one of the representative fruits and vegetables.

As a method for processing a hole having a diameter of 0.1 to 0.5 mm, for example, a very thin needle is heated to pierce and melt the film to open it, or a method using a carbon dioxide laser can be applied. Both are easy to process continuously and are inexpensive.

The method of processing the film into a bag is not particularly limited, but for example, a bag obtained by heat-sealing and cutting a film processed into a tubular shape by ordinary inflation molding is used. In the case of individual packaging, use the one that matches the shape of fruits and vegetables, or in the case of boxing, heat-seal the shape along the inside of a cardboard box.

The material of the film is required to be inexpensive and excellent in transparency and to have appropriate gas permeability. Resins satisfying this condition include low density polyethylene, high density polyethylene, polypropylene, ethylene-
Examples thereof include vinyl acetate copolymer, polystyrene, and cellulosic resins. Regarding the thickness of the film, considering the total gas permeability, and considering the appropriate strength and economic efficiency,
It is preferably 20 to 80 μm.

If necessary, an antifogging agent, a lubricant, an antiblocking agent, an antioxidant, an ultraviolet absorber, a coloring agent, an antistatic agent, etc. may be incorporated in the film constituting the bag.

The storage temperature may be low, of course, but in the case of the bag of the present invention, even if the temperature rises, the opening area is adjusted according to the breathing volume at each temperature.
CA conditions can be achieved. Therefore, especially 10 ℃
It is effective when used in a relatively high temperature range from 1 to 20 ° C.

[0022]

EFFECTS OF THE INVENTION Freshness is maintained for a long period of time by packaging fruits and vegetables in the packaging bag of the present invention and introducing the gas composition in the bag into a condition effective for maintaining the freshness. Currently, keeping freshness of fruits and vegetables by gas adjustment is often done using large storage, but it is costly to introduce and different conditions are different for each fruits and vegetables, so it is not possible to store many kinds of fruits at the same time. Can not. In the present invention, the effect of CA conditions can be obtained simply by packaging the fruits and vegetables in the packaging bag, which is simple and economical.

In particular, in the case of broccoli, even in the high temperature period from spring to summer when storage / transportation is difficult, low-temperature transport and complete cold / cold storage materials are not required, and styrofoam, which is a waste problem, is not required. Furthermore, if each product is hermetically packaged one by one in the production area, it is possible to sell the product at the store while maintaining the freshness-retaining effect without opening the package temporarily and exposing it to the outside air when unpacking.

[0024]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto.

The gas composition in the bag was determined by inserting a needle of a syringe into a rubber seal portion (area: 1 cm ² ) attached to a part of the bag, sampling the gas in the bag (10 cc), and measuring the oxygen concentration meter and the dioxide. It measured using each densitometer for carbon (made by Toray Engineering). Further, for the evaluation of freshness, the appearance and the change in color were visually observed, and for the odor, the offensive odor generated from inside the bag was sensory-evaluated according to the following criteria. Color: No discoloration is observed. △: Discoloration is slightly observed. ×: Discoloration is completely discolored. O: No offensive odor is felt. △: Offensive odor is slightly felt. ×: Severe offensive odor is rotted. : Not rotted at all △: Slightly spoiled part ×: Softened overall and many spoiled parts

Example 1 A surfactant (diglycerin monostain manufactured by Sakamoto Yakuhin) was added to the resin.
Inflation by adding 1.5% by weight of
Total surface area of 0.1m consisting of molded film ²Low density
Degree polyethylene bag (size 25 x 20 cm, thickness 60μ
m, oxygen permeability 4190 cc / m²・ Day, carbon dioxide
Element transmittance 18860 cc / m²・ Heat the needle to the day)
Puncture and open a hole with a diameter of 0.3 mm (hole diameter / thickness = 5)
6 packaging bags (total opening area 1.70mm per weight)²
/ Kg) 1 broccoli (250g) headspare
Heat-sealed with a base rate of 2
Was placed in a storage room at 20 ° C. and 65% RH. 10 days,
Measure the gas composition in the bag and observe the freshness of broccoli.
The results are shown in Table 2.

Example 2 A surfactant (diglycerin monostain manufactured by Sakamoto Yakuhin) was added to the resin.
Inflation by adding 1.5% by weight of
0.4m total surface area consisting of formed film ²Low density
Degree polyethylene bag (size 40 x 50 cm, thickness 60μ
m, oxygen permeability 4190 cc / m²・ Day, carbon dioxide
Element transmittance 18860 cc / m²・ Heat the needle to the day)
Puncture and open a hole with a diameter of 0.3 mm (hole diameter / thickness = 5)
Twenty-three packaging bags (total opening area 0.50 mm per weight)
²/ Kg) with 12 broccoli (3 kg) heads
Heat sealed with a pace rate of 2
Was placed in a storage room at 20 ° C. and 65% RH. 10 days,
Measure the gas composition in the bag and observe the freshness of broccoli.
The results are shown in Table 2.

From the results shown in Table 2, in Examples 1 and 2, after 2-3 days from the start of storage, the gas composition in the bag approaches the optimum CA condition of broccoli (oxygen 2%, carbon dioxide 10%) and equilibrates. And did not change until after 10 days. In addition, the freshness was maintained well, and it remained green and did not rot or smell.

Comparative Example 1 In Example 1, no holes were formed (total hole area per weight was 0 m).
m ² / kg), but the same as the example. The evaluation results are shown in Table 2.

Comparative Example 2 The same as Example 1 except that the number of openings is 3 (total opening area per weight is 0.07 mm ² / kg). The evaluation results are shown in Table 2.

Comparative Example 3 The same as Example 1 except that the number of openings is 18 (total opening area per weight is 4.5 mm ² / kg). The evaluation results are shown in Table 2.

Comparative Example 4 The same as Example 1 except that it was not packaged in a bag. The evaluation results are shown in Table 2.

As described above, in Comparative Example 1 having no openings and Comparative Example 2 having a low opening rate, oxygen in the bag was insufficient and carbon dioxide was excessive, and the green color was retained but the offensive odor was severe. Product value has been lost. On the contrary, Comparative Example 3 in which the aperture ratio is too large
In Comparative Example 4 in which the packaging was not provided, the oxygen concentration was high, so that respiration could not be suppressed and yellowing occurred. In the case of no packaging, wilting due to water evaporation was remarkable.

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuko Nakanishi 2-10-1 Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Chemical Co., Ltd.

Claims (5)

[Claims] 1. A bag for hermetically packing when storing fruits and vegetables,
The total open area is 0.4-4.
A packaging bag for keeping freshness of fruits and vegetables, which is provided with openings of 0 mm ² / kg and within a range of 3 <hole diameter / thickness <20. 2. The hole diameter is 0.1 to 0.5 mm.
The packaging bag for keeping freshness of the vegetables and fruits described. 3. A nonionic surfactant in the resin is 0.2 to 10.
The packaging bag for keeping freshness of fruits and vegetables according to claim 1 or 2, which is blended with 2.0% by weight. 4. When packaging fruits and vegetables in a bag using the packaging bag according to claim 1, 2 or 3, the ratio of the volume of air in the bag to the volume of fruits and vegetables (head space ratio) is 1 or more and 3 or less. How to maintain freshness of fruits and vegetables packaged in a box. 5. The method for maintaining freshness of fruits and vegetables according to claim 4, wherein the fruits and vegetables to be packaged are broccoli.