JP7628879B2 - Freshness-preserving packaging for fruits and vegetables - Google Patents

Description

This invention relates to freshness-preserving packaging for preserving the freshness of fruits and vegetables.

Synthetic resin film bags are commonly used as packaging for storing and transporting fruits and vegetables. Attempts have been made to maintain the freshness of fruits and vegetables for long periods of time by giving these bags a certain level of breathability and adjusting the amount of water vapor, oxygen concentration, and carbon dioxide concentration inside the bag. If water vapor accumulates inside the bag and condenses, the fruits and vegetables contained within can be damaged when they come into contact with the condensed water, so it has been proposed to punch holes in the bag to prevent water vapor from accumulating inside. However, with holes as large as punch holes, the oxygen permeability is too high, and even if condensation does not occur inside the bag, the oxygen concentration becomes the same as in the atmosphere, making it impossible to maintain the freshness of the fruits and vegetables. For this reason, studies are being conducted on opening smaller holes to ensure appropriate breathability.

For example, Patent Document 1 proposes a film for freshness-preserving bags for fruits and vegetables that ensures breathability by perforating the film with a needle that does not use heat, creating perforations in the synthetic resin film without reducing the processing speed.

However, if too many holes are made in the bag, it becomes difficult to protect the fruit and vegetables contained therein from external pressure. In response to this, and in order to ensure the protective performance of the contents, Patent Document 2 proposes a freshness-preserving packaging bag for fruit and vegetables in which the ratio of peak pressure (burst strength) to moisture permeability is adjusted to fall within a specified range.

On the other hand, if the holes become blocked, the expected breathability cannot be ensured. Possible causes for the holes to become blocked are deformation of the film due to the weight of the fruits and vegetables, contact with the side of the box when packed, or when the bags come into contact with each other when stacked.

Patent Document 3 proposes a freshness-preserving packaging bag in which the shape of the through-hole is oval and the direction of the through-hole is adjusted to prevent the shape of the through-hole from changing.

Patent Document 4 proposes a method of packing fruit and vegetable packages into a packaging box by making the angle between the bottom of the packaging box and the film material of the fruit and vegetable packages vertical or inclined, thereby preventing the pores of the fruit and vegetable packages from becoming blocked by each other.

Patent Document 5 proposes a packing method for packing fruit and vegetable packages flat in a box, in which the number of stacks is adjusted to prevent the pores from becoming clogged and maintain freshness retention.

JP 2020-029261 A JP 2018-100112 A Patent No. 6168228 JP 2020-37422 A JP 2020-70079 A

However, these proposed methods can cause inconveniences depending on the circumstances of use. When individual packages, such as edamame, in which multiple pods are packed together in one bag, are packed into multiple boxes for shipping, it has been confirmed that several problems arise during the process.

The bag using the film described in Patent Document 1 has slits in two directions processed with unheated needles, but when pressure is applied from the outside, the slits can become deformed around the slits and close. When packing individual packages containing edamame into an outer box, pressure is applied by hand to the individual packages to remove the air and reduce the volume of each package in order to increase the number that can be accommodated in the outer box. However, when the bag described in Patent Document 1 is used for edamame, the slits become blocked during this air removal process, making it difficult to remove the air, which can result in time-consuming packing work, reduced productivity, and in some cases, the individual packages can burst.

The packaging bag described in Patent Document 2 also places emphasis on cushioning to protect the contents, which makes it difficult for air to escape, and like Patent Document 1, there is a risk of the bag bursting or the productivity of the boxing process decreasing.

When edamame are packed in bags with punched holes, it is easy to remove the air and the productivity of the boxing process is high, but the oxygen concentration inside is almost the same as that of the atmosphere, so as mentioned above, the freshness of the edamame cannot be maintained.

Although the packaging bag described in Patent Document 3 has been used for edamame, it was not envisaged that the packaging bag would be used for packing edamame in a box, and the oxygen permeability was set on the assumption that the edamame would be stored in individual bags. For this reason, when attempting to pack the edamame in an outer box, the through holes are likely to become clogged due to contact between adjacent packaging bags, and it is believed that the expected freshness-preserving effect would not be achieved properly.

The fruit and vegetable package described in Patent Document 4 is intended to be packed into a packaging box after packaging the fruit and vegetable, but the focus is only on whether moisture is absorbed from the bottom. The document does not take into account the productivity of the work of packing individual packages containing many edamame pods into a packaging box, which is not anticipated in the document.

When trying to pack edamame in the packaging described in Patent Document 5, there is a limit to the number of bags that can be stacked in order to ensure adequate oxygen permeability, and the number of packages that can be packed into one outer box is also limited, resulting in a smaller number of items that can be stored per box and therefore poor transport efficiency.

Therefore, the objective of this invention is to provide a freshness-preserving package that can fully preserve freshness without reducing the productivity of the work of packing individual packages of edamame into boxes.

This invention is a packaging body in which edamame is stored in a film bag made of a breathable synthetic resin film, and the packaging body is packed in a breathable outer box,
The gas exchange rate E of the film bag in an environment of 23° C. and 60% RH is 1.0×10 ⁵ cc/m ² ·day·atm or more and 2.0×10 ⁵ cc/m ² ·day·atm or less;
The above problem was solved by providing a freshness-preserving package in which the edamame occupy a space volume ratio of 40% or more and 80% or less in the outer box.

By packing the edamame so that the space volume ratio of the edamame in the breathable outer box is within an appropriate range, and by also setting the gas exchange rate E of the film bag itself that stores the edamame within an appropriate range, breathability with the outside air can be ensured and the freshness of the edamame can be maintained. Furthermore, by packing the edamame within the above-mentioned space volume ratio range, the efficiency of transportation and storage can be improved, and the freshness-preserving effect can be prevented from being reduced due to the loss of breathability of the individual package caused by overpacking.

The individual packaging that constitutes the freshness-preserving packaging of this invention can adopt an embodiment in which the volume of air that escapes when a load of 1 kgf is applied for 1 minute after 1000 cc of air is injected into the film bag and sealed, is 250 cc or more and 980 cc or less. In applications in which edamame in an amount to be retailed to consumers is packed in boxes and transported and stored, if air escape properties within this range can be ensured, it becomes an ideal individual packaging that makes it easy to remove excess air during boxing without reducing productivity, and also easily exerts a freshness-preserving effect without excessive air escaping.

The exterior box constituting the freshness-preserving package according to the present invention may employ an embodiment in which the opening area ratio R is 0.001% or more and 60% or less.
By combining this with the condition that the gas exchange rate E of the film bag in an environment of 23°C and 60% RH is 1.0 x ¹⁰⁵ cc/m2· ^day ·atm or more and 2.0 x ¹⁰⁵ cc/ ^m2 ·day·atm or less, both the individual packaging containing edamame in the film bag and the outer box can exhibit appropriate breathability, and the breathability of the entire freshness-preserving packaging body of the present invention can be sufficiently ensured.

The material for the freshness-preserving packaging of this invention can be the synthetic resin film described above, which has been perforated using heat to a thickness of 15 μm to 60 μm. By perforating the synthetic resin film itself to make it breathable, it is possible to achieve stable performance with less unevenness in breathability, and by perforating using heat, film debris is less likely to be generated, which can prevent the film debris from being mixed into the edamame.

In particular, it is preferable to adopt an embodiment in which the ratio a/b of the long diameter a to the short diameter b of the micropores formed by the perforation is 1.0 or more and 3.5 or less. With such a shape, even if pressure is applied to remove air from the bag when storing edamame and packing it in a box, the micropores are unlikely to deform, so the micropores are unlikely to become blocked, and as long as the bag is packed in an outer box within the above-mentioned space volume ratio, the gas exchange rate E is unlikely to decrease.

In addition, if the exterior box is made of a cardboard box, an embodiment in which the opening area ratio R is 0.001% or more and 30% or less can be preferably adopted.

The freshness-preserving package of the present invention makes it possible to produce freshness-preserving packages in which many individual packages containing edamame are packed into a box while minimizing the workload. Edamame packaged in this freshness-preserving package can be transported and stored while maintaining its freshness, and can be conveniently transported from the production site to the consumption site while still stored in the outer box.

FIG. 1 is a partially transparent perspective view of a freshness-preserving package according to the present invention; An example of individual packaging in which edamame are packed in a film bag before being packed into a freshness-preserving package FIG. 1 is a plan view showing an example of a freshness-preserving package according to the present invention, in which individual packages are packed vertically in an outer box. Schematic diagram of perforations to be formed in the synthetic resin that constitutes the film bag Photographs showing the method for measuring air release in the examples

The present invention will be described in detail below with reference to an embodiment. The present invention is a freshness-preserving package used to package edamame.

The freshness-preserving package 1 according to the present invention is an individual package 13, in which multiple pods of edamame 2 are stored in a film bag 11 made of a breathable synthetic resin film, packed in a breathable outer box 15. Figure 1 shows a perspective view of an embodiment of the freshness-preserving package 1 using a cardboard box as the outer box 15, and Figure 2 shows a perspective view of an example of each individual package 13. Figure 3 shows a plan view of an example of the internal state of the individual packages 13 packed in the outer box 15.

The number of pods of edamame 2 stored in one film bag 11 is not particularly limited, but it is preferable that it is the amount that is retailed to general consumers in the market. The number of individual packages 13 packed in the outer box 15 is at least multiple, and if there are too few individual packages, the benefits of packing in the outer box 15 in terms of transportation and storage will not be fully obtained. Furthermore, it may actually be more time-consuming than transporting them as individually wrapped, which is a problem in terms of handleability. On the other hand, if too many are packed, the outer box will be large and heavy, making it difficult to handle the freshness-preserving package 1 by hand. Furthermore, if too many individual packages 13 are packed in without making the outer box larger, the edamame 2 contents may be easily damaged.

The synthetic resin film that constitutes the film bag 11 is not particularly limited in material, but it is necessary that it has no adverse effect on the edamame 2 and is durable enough not to be easily torn during storage and transportation. As a synthetic resin that satisfies these requirements, for example, a polyolefin film such as polyethylene or polypropylene is preferably used. This is particularly desirable from the standpoint of safety and cost. Among them, a polyolefin film with anti-fogging properties is more preferable because it can suppress the adhesion of water droplets that cause the edamame 2 to spoil due to condensation of water vapor released from the edamame 2 during transportation and storage.

The thickness of the synthetic resin film is preferably 15 μm or more, and more preferably 20 μm or more. If it is less than 15 μm, it may be easily torn, especially when it is made into a perforated film as described below, and it may be difficult to keep the size of the micropores formed inside the perforated portion within a suitable range. On the other hand, it is preferably 60 μm or less, and more preferably 50 μm or less. If it exceeds 60 μm, it becomes difficult to form a perforated portion of a suitable shape.

The synthetic resin film is used to make a film bag 11. Examples of the shape of the film bag include two-sided bags, three-sided bags, palm-shaped bags, and gusseted bags, but the shape is not particularly limited as long as the gas exchange rate E described below can be achieved. Also, examples of the method for making the bag and the method for sealing the storage opening of the film bag include heat sealing, melt-cut sealing, pack sealing, and zippers, but these methods are also not particularly limited as long as the gas exchange rate E described below can be achieved.

The film bag 11 for storing the edamame 2 preferably has a gas exchange rate E of 1.0×10 ⁵ cc/m ² ·day·atm or more in a 23° C., 60% RH environment, and more preferably 1.2×10 ⁵ cc/m ² ·day·atm or more. If it is less than 1.0×10 ⁵ cc/m ² ·day·atm, the breathability becomes insufficient, and there is a high possibility that the freshness of the edamame 2 stored in the film bag cannot be sufficiently maintained. On the other hand, the gas exchange rate E of the film bag 11 is preferably 2.0×10 ⁵ cc/m ² ·day·atm or less, and more preferably 1.8×10 ⁵ cc/m ² ·day·atm or less. If the breathability is too high, even if the edamame 2 is stored in the film bag, it will be too close to a situation where it is exposed to the atmosphere, and the freshness retention effect will not be exhibited.

In addition, the individual packaging body 13 in which edamame beans are stored in the film bag 11 and the storage opening is sealed is not only breathable, but also has the ability to allow an appropriate amount of air to escape when a load is applied, in order to facilitate the escape of the internal air during the boxing work and improve the productivity of the boxing work. Specifically, the air escape ability is preferably 250 cc or more, and more preferably 300 cc or more, when a load of 1 kgf is applied for 1 minute after 1000 cc of air is injected into the film bag and sealed. If the volume of the air escape is 250 cc or less, there is a high possibility that the air will not escape easily even if an attempt is made to reduce the volume of the individual packaging body 13 during the boxing work, and the productivity of the boxing work will decrease. On the other hand, it is preferable that the volume of the air escape is 980 cc or less, and more preferably 800 cc or less. If the amount of air escapes exceeds 980 cc, there is a risk that most of the internal air will escape during transportation, and the protective performance and freshness preservation effect of the edamame will not be exhibited.

To achieve the above gas exchange rate E and air escape property, it is desirable for the synthetic resin film itself to be breathable. Examples of structures that ensure breathability include those in which, after the film is manufactured, a hot needle or laser is used to heat-perforate the film to form the required number and size of perforations.

When using a film perforated with a hot needle or laser to ensure breathability in the synthetic resin film, the resin melted around the micro-holes cools and hardens when heat is applied during perforation. This makes it difficult for film residue to remain, and prevents film residue from adhering to the stored edamame. An enlarged view of the perforated portion 21 is shown in Figure 4. The peripheral portion 23, which melted and hardened due to heat, becomes thick, and micro-holes 22 are formed inside it. These micro-holes 22 may be circular or elliptical.

The ratio a/b of the long diameter a to the short diameter b of the micropores 22 in the perforated portion 21 is 1.0 or more, and is preferably 3.5 or less, and more preferably 3.0 or less. If the long diameter is so long that it exceeds 3.5, the peripheral portion 23 is likely to block the micropores 22 when air is removed from the bag during boxing, increasing the risk of impairing breathability.

In addition, the minor diameter b is preferably 0.05 mm or more, and more preferably 0.10 mm or more. If it is less than 0.05 mm, it is too small and air exchange is difficult, and the number of holes required to ensure breathability throughout the bag increases, which may reduce production efficiency or make it difficult to ensure the above-mentioned gas exchange rate E and air escape rate in the first place. On the other hand, the minor diameter b is preferably 1.0 mm or less, and more preferably 0.6 mm or less. If the minor diameter b exceeds 1.0 mm, the air escape rate and gas exchange rate E become too high, not only failing to exert the freshness-preserving effect, but also causing more air to escape during transportation, which may cause a loss of cushioning and a loss of protective performance. Furthermore, since each hole is clearly visible, there is a risk of impairing the appearance of printed parts such as brand markings.

The freshness-preserving package 1 according to the present invention is a box in which a number of individual packages 13 are packed in a breathable exterior box 15. The shape of the exterior box 15 is not particularly limited, and a cardboard box as shown in Figs. 1 and 3, a plastic perforated container (hereinafter referred to as a "plastic container"), a wooden box, etc. can be used. The sides of these exterior boxes may be formed with handle holes 16 as shown in Fig. 1 or ventilation holes 17 for vacuum pre-cooling, or may have holes separated by lattices for ventilation. However, boxes that are outer frame cases with completely open sides, such as boxes that are only rectangular parallelepiped frame parts other than the bottom, are not preferred. Examples of materials for the exterior box 15 include plastic, wood, and cardboard.

Of the various types of exterior boxes 15, the plastic containers mentioned above have the advantage of being highly durable and reusable, and can be used as returnable boxes. In addition, even if multiple ventilation holes are provided, the shape is easily maintained and strength is easily ensured. On the other hand, they are somewhat heavy, and the effort and transportation costs required to collect them for reuse are required. In addition, in most cases they must be washed before reuse, and the effort and cost of washing cannot be ignored.

Of the various forms of the outer box 15, the wooden box has the advantage of being environmentally friendly since it does not require materials derived from fossil fuels for its manufacture. Because the wooden boards support the sides, the box is easy to maintain its shape and ensure its strength even if ventilation holes are provided mainly on the sides. On the other hand, the weight of the outer box is very large compared to the contents, which can easily lead to reduced productivity in packing work and increased transportation costs. It is of course conceivable to reduce the weight by making the boards that form the wooden box thinner or reducing the area of the boards, but if the area of the boards is made too small, the individual packages will easily protrude from the sides, making it impossible to pack the packages or causing damage to the individual packages during transport and storage.

Among the forms of the outer box 15, the cardboard box described above is one-way and can be used hygienically. In addition, since the material itself has good breathability, the opening area can be reduced, and the strength of the box can be easily maintained. The shape of the cardboard box is not particularly limited as long as it is both breathable and strong, and for example, as shown in FIG. 1, it may be formed with a handle hole 16 for carrying and a ventilation hole 17 for increasing breathability. Since it is lighter than wooden boxes and plastic containers, the productivity of the boxing work is good, and since it can be stored in a sheet form when not in use, it does not take up much space in warehouses. Although the box itself is one-way, a system for recycling the material has been established, and there is also the advantage that the overall environmental load is small. In addition, in the freshness-preserving package 1 according to the present invention, the edamame 2 is packed in the form of an individual package 13 stored in a film bag 11, so that the strength of the cardboard box can be prevented from decreasing due to the water vapor emitted from the edamame 2.

The ratio R of the opening area to the external area of the outer box 15 is preferably 0.001% or more, and more preferably 0.01% or more. If it is less than 0.001%, even if the film bag 11 has breathability, the breathability of the material of the outer box 15 itself will not be enough to exchange gas with the outside air, and the freshness preservation effect will not be fully exerted. Note that the external area mentioned above is the total area of the actual or virtual surfaces formed by the outer frame part of the box, which can be considered as a rectangular parallelepiped. In the case of a cardboard that covers six sides, even if there is an opening such as a handle hole 16, it is the total area of the six sides assumed to have no openings. The overlapping part of the flap is not doubled. In the case of a perforated plastic container, etc., it is the total area of each side assumed to have no openings for each side that has an opening such as a vent hole. On the other hand, R is preferably 60% or less, and more preferably 50% or less. If it exceeds 60%, the individual packaging 13 will protrude and come into direct contact with the outside air, and the freshness preservation effect of the freshness preservation package 1 will be almost impossible to achieve. For reference, the cardboard box with the handle hole 16 and ventilation hole 17 shown in Figure 1 has an R of about 0.5%.

When the exterior box 15 is a cardboard box, it is more preferable that the opening area ratio R is 0.001% or more and 30% or less. Since the compressive strength of the cardboard box is supported particularly by the side portions, if R is too high, there is a risk of problems in terms of strength. On the other hand, as mentioned above, the material itself has high breathability, so breathability can be easily ensured even without many holes.

In the freshness preservation package 1 according to the present invention, the individual packages 13 are not particularly limited in the way of packing them into the outer box 15. For example, they may be packed vertically as shown in FIG. 3, or may be packed flat with multiple layers stacked vertically. However, the ratio of the volume of the edamame 2 itself to the volume of the outer box 15 in the freshness preservation package 1 (hereinafter referred to as the "space volume ratio") is preferably 40% or more, more preferably 45% or more. If the space volume ratio is less than 40%, the transportation efficiency is poor, and the edamame 2 move too freely in the outer box 15, which may damage the edamame 2. On the other hand, the space volume ratio is preferably 80% or less, more preferably 75% or less. If it exceeds 80%, most of the air in the individual packages 13 must be removed and the edamame 2 must be packed so tightly that they directly press against each other, which increases the risk of damage to the edamame 2 itself. In addition, if the outer box 15 is a cardboard box, it may be difficult to seal it.

The freshness-preserving package 1 of the present invention can be used to package, transport, and store edamame 2, allowing for an appropriate exchange of gas inside and outside the package while preserving freshness for a long time. In addition, because air can be appropriately released from the individual packaging body 13, the time and effort required for producing the freshness-preserving package 1 can be significantly reduced, improving the productivity of the boxing process.

Next, we will explain the invention in more detail by showing examples in which the invention has actually been put into practice.

The following synthetic resin films were prepared for use in the film bags. These were perforated by laser, non-heated needle, and punch processing so as to meet the specifications described in Table 1 below. However, the micropores perforated using non-heated needles in Comparative Examples 1 and 2 were slit-shaped, and only in Comparative Examples 1 and 2, the major axis a indicates the length of the slit, and the minor axis b indicates the width of the slit. In each of the Examples and Comparative Examples, the following air escape properties and gas exchange rate E were measured for the perforated synthetic resin film. In each of the Examples and Comparative Examples, edamame was stored in a bag made from the perforated synthetic resin film, the storage opening was sealed by heat sealing to form an individual package, and the bag was packed into each of the outer boxes shown in Table 1. The following films were used as the synthetic resin films before perforation.
Anti-fog biaxially oriented polypropylene film ("Anti-fog OPP" in the table) - thickness 30 μm, manufactured by Futamura Chemical Co., Ltd.: AF-642

<Air release measurement>
Each film was used to heat seal a 200 mm x 180 mm back-pasted bag, into which 1000 cc of air was injected using a gas syringe. When the needle of the gas syringe was inserted into the bag, the needle was inserted into a part where three sheets of cellophane tape (CT405AP 18, manufactured by Nichiban Co., Ltd.) were pasted in layers to prevent the bag from tearing. After the injection of air was completed and the needle was removed, the needle hole was quickly blocked with cellophane tape, and a 26 x 30 cm stainless steel plate (1 kg) was placed on the bag so that it was parallel to the floor. An example of this state is shown in the photograph in Figure 5. The bag was left to stand for 1 minute in that state, and the air was removed from the bag by the weight of the stainless steel plate. After 1 minute, the stainless steel plate was quickly removed from the bag, and the needle of the gas syringe was inserted into the bag to degas the air in the bag. Degassing with a syringe was repeated until all the air was removed from the bag, and the air release property of the film bag was evaluated based on the total volume of the degassed air. The calculated volume of the air released was shown in Table 1 as the air release property (cc).

<Gas exchange rate E measurement>
Using each film, a bag of 150 mm x 180 mm was prepared by heat sealing four sides, and a syringe nozzle for sampling was attached while avoiding the perforated portion of the perforated film. Next, the bag was degassed with an aspirator using the nozzle, and then 750 cc of nitrogen gas (purity 99.99% or more) was filled into the bag using a gas syringe. Immediately after filling with nitrogen gas, 1 cc of gas in the bag was sampled, and the oxygen concentration was measured by a gas chromatography (TCD detector) equipped with a packed column, and the value was taken as the initial oxygen concentration (C ₀ ). Then, the bag was stored stationary in a thermostatic chamber set at 23 ° C. and 60% RH, and the oxygen concentration in the bag was measured by gas chromatography 30 minutes, 1 hour, and 1 hour and 30 minutes after the start of storage. All measurements were performed in the atmosphere. It was confirmed that a proportional relationship was established between the elapsed time and the oxygen concentration in the bag (correlation function 0.98 or more) in the obtained measured values, and if this was not established, the test was performed again. The oxygen concentration in the air was set to 21%, and the gas exchange rate E of the entire air in the bag was calculated using the measured oxygen concentration in the bag 1 hour and 30 minutes after the start of storage according to the following formula.
E=(C _t −C ₀ )/C _O2 ×V/t/s/P……(1)
Here, each symbol is as follows:
E: Gas exchange rate (cc/ ^m2・day・atm)
_Ct : Oxygen concentration in the bag t hours after filling with nitrogen gas (%)
C ₀ : Oxygen concentration in the bag immediately after filling with nitrogen gas (%)
_CO2 : Oxygen concentration in the air (21%)
V: Amount of nitrogen gas filled (750cc)
t: time elapsed since gas filling (1.5 hr = 0.0625 days)
s: inner surface area of the bag (0.054 ^m2 )
P: atmospheric pressure during measurement (1 atm)

<Space volume ratio of edamame>
The edamame beans to be packed in the bags were sequentially placed in a 500cc graduated cylinder, with each pod in turn, until the top reached the 500cc mark, and then removed and the mass was measured, which was 250g. Therefore, the apparent volume per unit volume of the edamame used this time was calculated as 500cc/250g. The volumetric space ratio to the outer box was calculated using the following formula from the apparent volume per unit volume of the edamame, the total mass of the edamame packed in the outer box, and the volume of the outer box.

{Space volume ratio of edamame to the outer box (%)} = {apparent volume per unit volume of edamame (500cc/250g)} × {total mass of edamame packed in the outer box (g)} ÷ {volume of the outer box (cc)} × 100 (%)
The results were evaluated as follows:
◯: Space volume ratio is 40% or more and 80% or less; △: Space volume ratio is 30% or more and less than 40%, or more than 80% and 90% or less; ×: Space volume ratio is less than 30% or more than 90%.

<Evaluation of box packing workability>
The outer box was a cardboard box with a width of 36 cm, a length of 33 cm, and a height of 15 cm. Approximately 250 g of edamame was placed in a 200 mm x 180 mm film bag made by heat sealing three sides, and the storage opening was heat sealed to seal the individual packages. The number of individual packages shown in the table was prepared, and the time required for one person to vertically pack all the individual packages into the outer box was measured. The work was repeated three times, and in order to take into account variations due to individual differences, the same work was performed by different personnel, and the packing workability was evaluated as follows from the average time required for the work.
◯: Less than 1.5 minutes, △: 1.5 minutes or more but less than 3 minutes, ×: 3 minutes or more.

<Freshness preservation effect evaluation>
Using the synthetic resin film of each Example and Comparative Example, three sides were heat-sealed to form a film bag, and about 250 g of edamame was placed in the film bag, and the opening was heat-sealed to produce individual packages for each Example. Each package was vertically packed into each outer box for the number of packages shown in the table, and stored for 7 days in a fluctuating environment of 12 to 27°C. The quality of the edamame was evaluated comprehensively as follows, based on changes in appearance, the presence or absence of an abnormal odor, and changes in mass.
◯: Good, △: Poor, ×: Extremely poor.

The following outer boxes were prepared:
Cardboard box (1) - Rengo Co., Ltd., with handle holes and ventilation holes. Inner dimensions: 36 cm x 33 cm x 15 cm. Opening area ratio R = 1.8%.
Cardboard box (2) - Rengo Co., Ltd., no handle holes. Inner dimensions: 36 cm x 33 cm x 15 cm. Opening area ratio R = 0.005%.
Cardboard box (3) - Rengo Co., Ltd., no top. Inner dimensions: 36 cm x 33 cm x 15 cm. Opening area ratio R = 27%.
Plastic container: Santener B#19-N, manufactured by Sanko Co., Ltd. Inner dimensions: 44 cm x 27 cm x 15 cm. Opening area ratio R = 50%.
・Styrofoam: Kasahara Kogyo Co., Ltd., Styrofoam Box (L) TK-14H (Large), Inner dimensions: 40 cm x 31 cm x 18 cm. Opening area ratio R = 0%
・Wooden box: Made of pine wood, inner dimensions: 36cm x 33cm x 15cm, opening area ratio R = 72%

<Overall evaluation>
Based on the evaluation of the space volume ratio, packing workability, and freshness preservation effect, an overall evaluation was made as follows.
Good: All of the space volume ratio, packing workability, and freshness retention effect are good; △: Any of the space volume ratio, packing workability, and freshness retention effect are △; ×: Any of the space volume ratio, packing workability, and freshness retention effect are ×.

<Comparison of different perforation shapes>
(Examples 1 to 4)
A synthetic resin film was obtained by perforating an anti-fog biaxially stretched polypropylene film with a laser under different conditions so that the major and minor diameters of the perforated portion were the values shown in Table 1. The synthetic resin film was evaluated for air escape and gas exchange rate E, and about 250 g of edamame was packed into a film bag made by heat sealing three sides of each synthetic resin film, and the remaining side of the storage opening was heat sealed to obtain an individual package. 20 of these individual packages were packed vertically in a cardboard box (1) to evaluate the packing workability and freshness retention effect, and all of the ranges of Examples 1 to 4 showed good results.

<Comparison based on number of individual packages>
(Examples 5 and 6)
Using the synthetic resin film and film bags of Example 1, the number of individual packages packed into the same cardboard box (1) was changed to 16 packages (Example 5) and 26 packages (Example 6) to change the volumetric space ratio, and good results were obtained in all cases within this range.

<Evaluation of differences in air release properties of film bags>
(Comparative Examples 1 and 2)
When individual packages were produced in the same manner as in Example 1 using the anti-fog biaxially oriented polypropylene film used in Example 1 and a film bag made by perforating the film with a non-heated needle (Comparative Examples 1 and 2), the air escape property was insufficient, and the boxing work took a significantly long time.

(Comparative Example 3)
When individual packages were similarly produced using a synthetic resin film in which the number of perforations per unit area was reduced to 80 perforations/ ^m2 , instead of forming the perforations so that the major axis a of the perforations was longer than in Example 1, the air escape property was insufficient, and the boxing work took a little longer. It was confirmed that the air escape property deteriorates when the major axis/minor axis ratio of the ellipse is too large.

(Comparative Example 4)
In Comparative Example 3, individual packages were produced in the same manner except that the number of holes was increased by 1.5 times to 120. Although the air could be released and the time required for packing was shortened, the gas exchange rate E increased and the freshness-preserving effect of the edamame became insufficient.

(Comparative Example 5)
When individual packages were produced in the same manner as in Example 1 using a film bag made of a film having a circular punch hole with a diameter of 6.0 mm formed as the perforated portion, the air escaped too easily, and the air inside was completely escaped when the air escape property was measured. In addition, the gas exchange rate E could not be measured because the packed air escaped immediately. Although the productivity of the boxing work was good, the freshness preservation effect of edamame was not exhibited at all.

<Evaluation of differences in gas exchange rates>
(Comparative Examples 6 and 7)
In Example 1, when the number of holes was halved, the air escape was ensured, but the gas exchange rate E was reduced, resulting in insufficient freshness preservation effect (Comparative Example 6). In this Comparative Example 6, when the number of individual packages packed in the outer box was reduced from 20 to 8 (Comparative Example 7), the freshness preservation effect was ensured due to the increased spacing between the individual packages. However, the spatial volume ratio of edamame was significantly reduced, making it impractical in terms of transportation efficiency, and it was confirmed that a practical problem would occur if the gas exchange rate E was reduced too much.

<Evaluation of floor area ratio>
(Comparative Examples 8 and 9)
In Example 1, the number of individual packages packed in an outer box was changed from 20 to 29 (Comparative Example 8) and 8 (Comparative Example 9). In Comparative Example 8, in order to pack that many individual packages, the air had to be sufficiently removed before packing, which took too much time, causing problems in productivity of the boxing work. In addition, there was almost no gap between the bags of the individual packages, and it was thought that the holes were blocked by adjacent bags, resulting in insufficient freshness preservation effect. On the other hand, in Comparative Example 9, in which the number of individual packages was reduced, there was almost no need to remove air, and the packages were packed as they were, so the productivity of the work was good and the freshness preservation effect was secured in the same way as in Example 1, but the number of packages packed in one outer box was too small, causing problems in efficiency of transportation and storage.

<Evaluation based on differences in exterior packaging>
(Examples 7 to 9, Comparative Examples 10 and 11)
In Example 1, the outer box was changed to a cardboard box (2) (Example 7), a cardboard box (3) (Example 8), a plastic container (Example 9), polystyrene foam (Comparative Example 10), and a wooden box (Comparative Example 11), and the individual packages were packed in the same manner. Note that only in Comparative Example 10 of polystyrene foam, the number of individual packages packed in the box was increased by two because the internal volume was large. In all of Examples 7 to 9, the opening area ratio R of the outer box was different, but the breathability was ensured and no problem occurred in the freshness preservation effect. On the other hand, in Comparative Example 10, where the opening area ratio R of the outer box was 0% and there was no breathability, even if the air escape property and gas exchange rate E of the individual packages were ensured, the air that escaped from them was not exchanged with the outside air, so the freshness preservation effect was not exhibited at all. In addition, the wooden box was essentially a wooden frame and could not support the packed individual packages, and the form of collective packaging could not be maintained.

1 Freshness-preserving packaging body 2 Edamame 11 Film bag 13 Individual packaging body 15 Outer box 16 Handle hole 17 Ventilation hole 21 Perforated portion 22 Microhole 23 Periphery

Claims (4)

The individual packaging body, in which edamame is stored in a film bag made of a synthetic resin film having breathability due to micropores formed by perforation, is packed in a breathable outer box,
The gas exchange rate E of the film bag in an environment of 23° C. and 60% RH is 1.0×10 ⁵ cc/m ² ·day·atm or more and 2.0×10 ⁵ cc/m ² ·day·atm or less;
The film bag has a volume of air that escapes when 1,000 cc of air is injected into the film bag and a load of 1 kgf is applied for 1 minute, the volume of air that escapes being 250 cc or more and 980 cc or less;
The opening area ratio R to the outer area of the outer box is 0.001% or more and 60% or less,
The freshness-preserving package in which the edamame occupies a space volume ratio of 40% or more and 80% or less in the outer box. The freshness-preserving package according to claim 1, wherein the synthetic resin film is a polyolefin film having a thickness of 15 μm or more and 60 μm or less. The freshness-preserving package according to claim 2, wherein the ratio a/b of the major axis a to the minor axis b of the micropores formed by the perforation is 1.0 or more and 3.5 or less. The freshness-preserving package according to any one of claims 1 to 3, wherein the outer box is made of a cardboard box and the opening area ratio R is 0.001% or more and 30% or less.

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