JP2020079092A - Fruit and vegetables-storing package, and freshness keeping method of fruit and vegetables - Google Patents

Abstract

To provide a fruit and vegetables-storing package capable of keeping freshness of fruit and vegetables.SOLUTION: In a fruit and vegetables-storing package, which is formed by packaging fruit and vegetables with a packaging bag constituted of a synthetic resin film, the rate of change of an oxygen concentration {(oxygen concentration after treatment)/(oxygen concentration before treatment)×100}(%) in the packaging bag before and after performing a following treatment is 0.5% or higher and 400% or lower, and an oxygen permeation amount at 23°C and 60%RH is 2 cc/m-day-atm or more and 50,000 cc/m-day-atm or less; the treatment: the packaging bag is held for 3 days under a condition of 20°C and 50%RH.SELECTED DRAWING: None

Description

  The present invention relates to a package containing fruits and vegetables and a method for maintaining freshness of fruits and vegetables.

  Conventionally, as a method of maintaining the freshness of harvested fruits and vegetables, a method of appropriately suppressing the respiration of the fruits and vegetables is known. A packaging bag used to maintain the freshness of such fruits and vegetables is known as MA (Modified Atmosphere) packaging.

  For example, in Patent Document 1, a packaging bag is used that shuts out air from the outside, and the gas concentration in the packaging bag is 5% or more and less than 10% oxygen concentration, 15 to 35% carbon dioxide gas concentration, and the remaining nitrogen. A method of preserving processed fresh vegetables containing lettuce filled with gas is disclosed.

JP, 2011-80, A

  However, since the technique described in Patent Document 1 blocks the inflow and outflow of air from and to the outside, the oxygen concentration decreases and the carbon dioxide concentration becomes too high due to breathing of fruits and vegetables such as lettuce during storage. However, there were problems such as gas troubles and offensive odors.

  The present inventor has made earnest studies to solve the problems of the prior art, and first found that it is not sufficient to simply specify the oxygen permeation amount as a condition that the package should have. Then, as a result of further studies on the assumption that a packaging bag having a predetermined oxygen permeation amount is used, it is possible to control the rate of change of the oxygen concentration when a predetermined process is performed on a package in which fruits and vegetables are packaged, The present invention was completed for the first time when it was found to be effective as a design guideline for improving the freshness retention of fruits and vegetables.

The present invention is a package containing fruits and vegetables obtained by packaging fruits and vegetables with a packaging bag composed of a synthetic resin film,
The rate of change in oxygen concentration in the package before and after the following treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less ,
Provided is a package containing fruits and vegetables, which has an oxygen permeation amount at 23° C. and 60% RH of ² cc/m ² ·day·atm or more and 50000 cc/m ² ·day·atm or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 50% RH.

Further, the present invention is a method of maintaining freshness of fruits and vegetables for packaging fruits and vegetables with a packaging bag made of a synthetic resin film,
The rate of change in oxygen concentration in the package before and after the following treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less ,
Provided is a method for keeping freshness of fruits and vegetables, in which the fruits and vegetables are packaged so that the amount of oxygen permeation at 23° C. and 60% RH is ² cc/m ² ·day·atm or more and 50000 cc/m ² ·day·atm or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 50% RH.

  ADVANTAGE OF THE INVENTION According to this invention, the package containing fruits and vegetables which can maintain the freshness of fruits and vegetables for a longer period of time can be provided.

<Packaging bag>
Hereinafter, embodiments of the present invention will be described in detail.

The packaging bag in the present embodiment is for packaging fruits and vegetables inside. The fruits and vegetables are not particularly limited, for example, lobster, spinach, komatsuna, Mizuna, mibuna, asparagus, kushinsai, lettuce, thyme, sage, parsley, italian parsley, rosemary, oregano, lemon balm, chives, lavender, salad. Barnet, ramsyear, rocket, dandy lion, nastatum, basil, arugula, watercress, moloheiya, celery, kale, leek, cabbage, cabbage, chrysanthemum, saladana, sanchu, butterbur, nabana, bok choy, honeywort, seri, cabbage, broccoli, cauliflower , Myoga, radish, carrot, burdock, radish, turnip, sweet potato, potato, potato, yam, taro, ginenjo, yamato, pepper, paprika, shishito, cucumber, eggplant, tomato, cherry tomato, pumpkin, bitter melon, okra, sweet corn , Green soybeans, green beans, green beans, broad beans, fungi and the like. In addition, fruits such as citrus fruits, apples, pears, grapes, blueberries, persimmons, strawberries and cut flowers are also effective. Further, it is also effective in a state where these are cut, so-called cut vegetables and cut fruits.
Among them, cut vegetables are preferable from the viewpoint of effective preservation.

Further, the oxygen permeation amount at 23° C. and 60% RH of the packaging bag is preferably ² cc/m ² ·day·atm or more, more preferably 5 cc/m ² from the viewpoint of maintaining the respiration and freshness of fruits and vegetables. m ² ·day·atm or more, more preferably 300 cc/m ² ·day·atm or more.
On the other hand, the oxygen permeation amount at 23° C. and 60% RH of the packaging bag is preferably 50,000 cc/m ² ·day·atm or less, and more preferably 10,000 cc/m ² ·, from the viewpoint of maintaining quality and freshness of fruits and vegetables. It is not more than day·atm, more preferably not more than 7500 cc/m ² ·day·atm.

  The amount of oxygen permeation is measured, for example, for each of the packaging bag immediately after being filled with nitrogen and the packaging bag after being left for a certain period of time after being filled with nitrogen, and measuring the oxygen concentration in the packaging bag to determine the oxygen concentration gradient. Can be calculated from

  Further, in the present embodiment, the oxygen permeation amount of the packaging bag is the selection of the material of the synthetic resin film described later, the method for producing the synthetic resin film, the layer structure of the synthetic resin film, the presence or absence of through holes and the average diameter of the through holes, It can be adjusted by controlling the number.

The water vapor permeability of the packaging bag at 40° C. is 2 g/m ² ·day or more, preferably 4 g/m ² ·day·atm or more, more preferably 6 g, from the viewpoint of releasing water vapor due to respiration of fruits and vegetables. /M ² ·day·atm or more.
On the other hand, the water vapor permeability of the packaging bag at 40°C is 10 g/m ² ·day·atm or less, preferably 8 g/m ² ·day·atm or less, and more preferably from the viewpoint of suppressing respiration of fruits and vegetables. Is 7 g/m ² ·day·atm or less.

  The water vapor transmission rate can be measured by a method based on JIS Z0208 (cup method).

  In the present embodiment, the water vapor transmission rate of the packaging bag, the selection of the material of the synthetic resin film described later, the synthetic resin film manufacturing method, the layer structure of the synthetic resin film, the presence or absence of through holes and the average diameter of the through holes, the number, etc. Can be adjusted by controlling.

  The packaging bag of the present embodiment can further enhance the freshness retaining effect by satisfying the following requirements.

  Through holes may be formed in the packaging bag. This makes it possible to stably adjust the water vapor transmission rate and the oxygen transmission amount. This makes it possible to effectively maintain the freshness of fruits and vegetables.

  The planar shape of the through hole may be circular, polygonal, or slit, for example. The circular shape is not limited to a true circular shape, but includes a substantially circular shape. In addition to the circular shape, it may have a semicircular shape or a crescent shape. The polygon may be a shape surrounded by three or more line segments such as a triangle, a quadrangle, and a pentagon. The slit is a slit penetrating the synthetic resin film forming the packaging bag, a slit, and may be a straight line, a curved line, an L-shape, an X mark, or the like, and its length is not particularly limited. ..

The average diameter of the through holes is preferably 30 μm to 1100 μm, and more preferably 50 μm to 500 μm. When it is at least the above lower limit value, the water vapor permeability and the oxygen permeation amount are improved, and mold generation is easily suppressed. On the other hand, when the amount is not more than the above upper limit, it is possible to prevent the invasion of foreign matter and to suppress the wilting and axis wilting of fruits and vegetables.
The average diameter of the through holes is calculated from the open area of the through holes with the through holes as a perfect circle.

The number of through holes with respect to the inner area of the packaging bag is preferably 1/m ² or more and 1500/m ² or less, more preferably 2/m ² or more and 1000/m ² or less, It is more preferable that the number is 10 pieces/m ² or more and 800 pieces/m ² or less.

Further, when the cross-sectional view of the through-hole is taken, Sout/Sin>1.1 is preferable, where Sout is the hole area on the outer surface of the packaging bag and Sin is the hole area on the inner surface of the packaging bag. That is, since the pore area on the outer surface is larger than the pore area on the inner surface, the deformation of the pores due to the weight of the fruit and vegetables can be reduced, and the gas concentration in the packaging bag is more stable, which improves the freshness of the fruit and vegetables. It becomes easier to hold. From the viewpoint that the flow paths for oxygen and water vapor are secured and the concentration is stable, deterioration or spoilage of fruits and vegetables can be suppressed more stably.
In this case, the average hole diameter of the through holes indicates the hole diameter on the inner surface of the packaging bag.

  Further, when the through hole is viewed in cross section, the side wall of the through hole is preferably tapered so as to gradually expand from the inner surface of the packaging bag toward the outer surface thereof. By making the shape of the taper, the deformation of the holes can be further reduced, and the freshness can be more stably maintained.

The method for forming the through hole is not particularly limited, and a known method can be adopted. Examples of such known methods include a laser processing method, a needle processing method including a hot needle, and a method using a die such as a roll cutter.
The through hole with Sout/Sin>1.1 can be formed by a laser processing method or the like. By the laser processing method, the diameter of the through hole can be adjusted, for example, by synchronizing the running speed of the synthetic resin film and the frequency of the laser, and the shape of the through hole matches the shape of the laser. By adjusting the focal length of the laser, it is possible to make it closer to a tapered shape from a cylindrical shape.

  The above-mentioned through holes may be previously formed in the synthetic resin film when the packaging bag is manufactured, or may be formed after forming the synthetic resin film into a bag shape, and the synthetic resin film is formed into a bag shape. It may be formed before and after the process.

Further, the inner surface area of the packaging bag in the present embodiment can be appropriately set according to the shape, size, handleability, etc. of the fruits and vegetables to be packaged. For example, the internal surface area of the packaging bag per fresh produce 100 g, may be 100 cm ² or more 5000 cm ² or less, may be 300 cm ² or more 700 cm ² or less.

  Next, the synthetic resin film constituting the packaging bag will be described.

  The synthetic resin film is preferably transparent or translucent, and more preferably transparent, from the viewpoint of visually recognizing fruits and vegetables from the outside. It may also be printed for the purpose of identifying fruits and vegetables.

The synthetic resin forming the synthetic resin film is not particularly limited as long as it can be used for packaging fruits and vegetables, and known ones can be used.
Examples thereof include various polyethylene and ethylene copolymers, polypropylene, polyvinyl chloride, polystyrene, acrylic resins, polyester resins such as polyethylene terephthalate and polylactic acid, and polyamide resins such as 6 nylon. These may be homopolymers, two or more kinds of copolymers, or a blend containing two or more kinds of these homopolymers and copolymers.
Specific examples of the above-mentioned various polyethylenes and ethylene copolymers include ethylene/vinyl alcohol copolymers, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, metallocene-linear low density. Examples thereof include copolymers such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-propylene copolymer, and ethylene-α-olefin copolymer, and ionomers. These may include one kind or two or more kinds, or may be a mixture of these and other resins.

  Among them, from the viewpoint of appropriately controlling the water vapor transmission rate and the oxygen transmission rate, polyethylene, ethylene/vinyl alcohol copolymer, polypropylene, polystyrene, polyester resin such as polylactic acid, and polyamide resin such as nylon are preferable. More preferably, ethylene/vinyl alcohol copolymer, polystyrene, polylactic acid, and nylon.

  From the viewpoint of cost and physical properties, it is preferable to use a heat-sealable stretched polypropylene film, a low density polyethylene film, a linear low density polyethylene film, or a metallocene catalyst polyethylene.

The method for molding the synthetic resin film is not particularly limited, but methods such as extrusion, inflation and calendering are used. When molding the synthetic resin film, additives such as an antifogging agent may be kneaded as necessary, or two or more kinds of resins may be blended.
Further, the synthetic resin film may be subjected to stretching treatment, annealing, etc., and may further be provided with a sealant layer. Among them, the stretching treatment can improve the rigidity, pinhole resistance, water vapor/oxygen barrier property, and appearance of the synthetic resin film. For example, stretched nylon, stretched polylactic acid, and stretched polystyrene are preferable.

  The synthetic resin film may be used as a single layer or may be used as a multilayer structure of two or more layers.

  For example, when the fruits and vegetables packaged in the packaging bag are heavy, polyethylene is dry laminated, extruded laminated, and coextruded to form a multilayer film on a film such as unstretched polypropylene, stretched polypropylene, unstretched nylon, stretched nylon, or stretched polyester. It is preferable to use a film.

  The average thickness of the synthetic resin film is preferably 15 μm or more and 400 μm or less, more preferably 20 μm or more and 200 μm or less, and further preferably 25 μm or more and 100 μm or less. When the content is at least the above lower limit value, the oxygen permeation amount and the water vapor permeation rate can be more easily controlled, and the strength of the packaging bag can be increased. On the other hand, when the content is not more than the above upper limit, the handling property of the packaging bag is improved, appropriate water vapor transmission rate and oxygen transmission rate are imparted, and the production cost can be reduced.

<Package with fruits and vegetables>
The fruit and vegetable-containing package according to the present embodiment contains the fruits and vegetables in the above-described packaging bag according to the present embodiment.

The package with fruits and vegetables according to the present embodiment is based on the assumption that the oxygen permeation amount at 23° C. and 60% RH is ² cc/m ² ·day·atm or more and 50000 cc/m ² ·day·atm or less. The rate of change of oxygen concentration in the package before and after the treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 50% RH.

  That is, the package with fruits and vegetables in the present embodiment improves the freshness retention of fruits and vegetables by satisfying the condition of a specific oxygen concentration change rate on the premise of a predetermined amount of oxygen permeation. Although details of the reason why such an effect is obtained are not clear, it is presumed as follows. Since the oxygen concentration in the package greatly affects the freshness of fruits and vegetables, it is important to control the oxygen concentration in the package to an appropriate range, but even if the oxygen permeation amount of the packaging bag itself is controlled. , Oxygen concentration in the package changes due to respiration of fruits and vegetables during storage. Therefore, the condition of 20° C. and 50% RH assumes an environment in which fruits and vegetables are packaged, distributed as products, and stored, and the change rate of oxygen concentration in the package stored under such conditions is It is considered that the oxygen concentration in the package will be easily maintained in an appropriate range by controlling at a level different from the conventional technique. As a result, the effect of maintaining the freshness of fruits and vegetables can be improved.

The oxygen change rate is 0.5% or more and 400% or less, preferably 1% or more and 350% or less, more preferably 2% or more and 300% or less, and further preferably 10% or more. It is 200% or less.
Setting the rate of change in oxygen concentration to the lower limit or higher intends to increase the change in oxygen concentration before and after the treatment, and indicates that the respiration rate of fruits and vegetables during the course of storage has been optimized. As a result, it is possible to suppress the generation of various bacteria and to suppress discoloration, texture and taste due to anaerobic respiration (oxygen deficiency).
On the other hand, setting the rate of change in oxygen concentration to the upper limit or less is intended to reduce the change in oxygen concentration before and after the treatment, and indicates that the respiration rate of fruits and vegetables during the preservation process is not extremely deviated from the optimum value. . As a result, it is possible to suppress the generation of various bacteria and to suppress discoloration, texture and taste due to anaerobic respiration (oxygen deficiency).

  Incidentally, such oxygen concentration change rate, by selecting the material of the synthetic resin film, the method of manufacturing the synthetic resin film, the layer structure of the synthetic resin film, the presence or absence of through holes and the average diameter of the through holes, by adjusting the number, etc. Can be controlled.

  In order to store fruits and vegetables inside the packaging bag and heat seal the package, a heat-sealing treatment may be applied to the opened portion, or a member such as a back sealing tape, a binding band, a rubber band, or caulking may be used. .. Among them, from the viewpoint of enhancing the freshness-keeping effect of fruits and vegetables, it is preferable to heat-seal the opening.

  Vegetables and vegetables may be washed after harvesting, those that have been wet with rain, snow, or dew and packed without draining. Thereby, workability can be improved. On the other hand, the moisture adhering to the fruits and vegetables may be removed by vacuum pre-cooling or the like from the viewpoint of storing the fruits and vegetables at a low temperature early to maintain their freshness or removing the influence of moisture on the fruits and vegetables as early as possible.

  The weight retention rate of the package with fruits and vegetables in the present embodiment is preferably 95% or more, more preferably 97% or more, and further preferably 98% or more. With such a value, the freshness of fruits and vegetables can be maintained more stably.

<How to maintain freshness of fruits and vegetables>
The method for packaging fruits and vegetables in the present embodiment is a method for maintaining freshness of fruits and vegetables for packaging fruits and vegetables with a packaging bag made of a synthetic resin film,
Further, the present invention is a method of maintaining freshness of fruits and vegetables obtained by wrapping fruits and vegetables in a packaging bag composed of a synthetic resin film,
The rate of change in oxygen concentration in the package before and after the following treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less ,
The fruits and vegetables are packaged so that the oxygen permeation amount (cc/m ² ·day·atm) at 23° C. and 60% RH is 2 or more and 50000 or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 50% RH.
This makes it possible to effectively maintain the freshness of fruits and vegetables.

  The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted.

  Next, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples.

(Example 1)
First, a polypropylene resin (manufactured by Japan Polypro Co., product number WFW5T) was prepared as a synthetic resin material. Next, the melt obtained by melting the film raw material was extruded from a T-die at a temperature of 230°C.
Then, the extruded melt was subjected to a stretching treatment of 5 times length×9 times width to obtain a biaxially stretched polypropylene film (synthetic resin film) having a final thickness of 25 μm.
Using the synthetic resin film, two sheets were superposed so that the inner layer film surface was on the inner side, and heat-sealing was applied to three sides using an impulse sealer (Fl-400Y-10PK manufactured by Fuji Impulse Co., Ltd.) to obtain a 10 mm width. A heat-sealed portion was formed at 160° C. for a sealing time of 1 second to produce a packaging bag. The bag size (inner size) of the obtained packaging bag was 200 mm×160 mm.
Next, fruits and vegetables (150 g of cut cabbage) were placed in the obtained packaging bag and the packaging bag was sealed to produce a package containing fruits and vegetables.

(Example 2)
A package containing fruits and vegetables was produced in the same manner as in Example 1 except that fine holes having an average pore diameter of 80 μm were perforated so that the number of inner areas of the packaging bag was 30 per 1 m ² .

(Example 3)
A biaxially stretched nylon film (manufactured by Unitika Ltd., trade name “Emblem ONBC” thickness 25 μm) was used as a synthetic resin film, and fine holes having an average pore diameter of 120 μm were perforated so that the number of the inner perimeter of the package was 60 per 1 m ² . A package containing fruits and vegetables was produced in the same manner as in Example 1 except for the above.

(Comparative Example 1)
A package containing fruits and vegetables was produced in the same manner as in Example 1 except that micropores having an average pore diameter of 2000 μm were perforated so that the inner area of the package was 2000 per 1 m ² .

(Comparative example 2)
A package containing fruits and vegetables was produced in the same manner as in Example 3 except that the product was not perforated.

  The following measurements were performed for each of the obtained packages containing fruits and vegetables. The results are shown in Table 1.

<Measurement>
・Measurement of gas concentration in packages containing fruits and vegetables:
The fruits and vegetables (150 g of cut cabbage) were packed in a packaging bag (packing bag size (inner dimension) 200 mm×160 mm), and immediately, the gas inside the package was measured using Check Point O ₂ /CO ₂ manufactured by MOCON Europe.

-Oxygen concentration change rate (oxygen change rate): The package is stored under conditions of 20°C and 50% RH for 3 days, and the oxygen concentration in the package before and after the treatment is measured. )/(Oxygen concentration before treatment)×100] (%).

・Measurement of water vapor transmission rate (g/m ² ·day·atm) of packaging bag at 40° C. Water vapor transmission rate test method (cup method) for moisture-proof packaging material (JIS Z0208) except that the temperature is set to 2° C. and the humidity is set to 60%. ).

・Measurement of oxygen permeation amount (cc/m ² ·day·atm) at 23° C. and 60% RH of the packaging bag (1) Encapsulation of nitrogen gas After sealing the bag with a heat seal or the like, use the aspirator or the like to open the bag. Degassed. Deaeration was performed until both sides of the bag were stuck. Next, this bag was filled with nitrogen gas (purity 99.9% or more) using a white hard syringe. The amount of nitrogen gas to be injected is adjusted to the bag size, and as much as possible is put in the range where the film forming the bag is not tensioned by the injected nitrogen gas and is slightly loosened, and the scale of the white hard syringe is used. Was measured. Note that degassing and injection of nitrogen gas were performed, for example, by piercing the bag with an injection needle. When sticking an injection needle, a double-sided tape was attached to the film forming the bag, and an adhesive tape made of polypropylene film (hereinafter referred to as "PP tape") was further attached onto the film. In addition, after removing the injection needle, the needle hole was immediately closed with PP tape. The tape attached to the bag was designed to fit in an area of 4.5 cm ² or less.
In addition, when the film forming the bag is a microporous film, the tape was set so as not to close the micropores.
(2) Measurement of initial oxygen concentration The initial oxygen concentration (C0) in the bag was measured immediately after filling with nitrogen gas (t=0). The gas in the bag was sampled and the initial oxygen concentration (C0) in the bag was determined by gas chromatography (TCD). C0 was 0.2% or less, and when it exceeded this, the work was redone. The sampling gas for measuring the oxygen concentration was 10 cc or less. When injecting into gas chromatography, a fixed amount of about 1 cc was injected. The standard gas (at least two points containing about 1% and about 10% oxygen) was also measured by injecting the same amount of gas to create a calibration curve.
(3) Storage of bag The bag whose initial oxygen concentration was measured was stored at 23° C. and 60% RH (constant temperature and humidity chamber). At this time, the bag was left still so that an object did not get on the bag and the wind of the fan in the constant temperature and humidity chamber did not hit the bag directly.
(4) Measurement of oxygen concentration in the bag during storage and calculation of oxygen permeation rate The oxygen concentration in the bag was measured immediately after filling with nitrogen gas and after 3 hours or more within an oxygen concentration range of 1% to 7%. It is necessary to measure a total of 3 to 5 points or more, and establish a proportional relationship (correlation coefficient is 0.98 or more) between the elapsed time t (hr) and the oxygen concentration in the bag. If the correlation coefficient did not hold, a retest was performed. If the oxygen permeation rate of the film forming the bag is too high and the oxygen concentration in the bag rises too fast, and this condition cannot be cleared, it is known that the oxygen permeation rate of a part of the film is smaller than the film being measured. The same process may be performed by laminating a film made of the same material to form a bag. At this time, the oxygen permeation rate of the measurement film was obtained by subtracting the oxygen permeation rate of the known film portion from the obtained oxygen permeation rate, excluding the portion bonded to another film whose surface area was known.
The oxygen permeation rate was calculated by the following calculation formula (1) using the value with the longer elapsed time.
F=1.143×(Ct−C0)×V/t (1)
However, F: oxygen transmission rate (cc/bag·day·atm)
Ct: oxygen concentration (%) in the bag t hours after filling with nitrogen gas
C0: oxygen concentration (%) in the bag immediately after filling with nitrogen gas
V: amount of filled nitrogen gas (cc)
t: elapsed time from gas filling (hr)

-Measurement of average pore diameter (μm) of through-holes Using a microscope (VH-6300 manufactured by Keyence Corporation), the open surface area of the inner surface of the packaging bag was measured at 5 points. The diameter was calculated from the area of the opening assuming that the opening was a perfect circle, and the average diameter was calculated.

-Measurement of hole area (Sout) of through-holes on the outer surface of the packaging bag and hole area (Sin) on the inner surface of the packaging bag: a packaging bag (20°C) using a microscope (VH-6300 manufactured by Keyence Corp.) The open area of the through hole was measured for each of the inner surface side and the outer surface side.

-Calculation of the inner surface area (cm ² ) of the packaging bag per 100 g of fruits and vegetables Dividing the double value of the bag size (inner dimension) (cm ² ) of the packaging bag by the content of the fruits and vegetables (g)/100, Calculated.

<Evaluation>
Each of the packages containing fruits and vegetables obtained above was stored at 10° C. for 5 days. After that, the cut cabbage was taken out from the package, and comprehensively evaluated by a plurality of specialized panelists for "presence or absence of discoloration", "good or bad texture", and "good or bad flavor".

-Freshness retention days-1: The contents were taken out from two samples (packaging bodies), and the general viable cell count was measured using a Petrifilm (AC plate) manufactured by 3M, and the average value of the general viable cell count was 10 ^6. The number of days until the above was measured. It should be noted that multiple samples are prepared and the measurement is performed once a day.The measured sample is not used for the subsequent measurement because the gas concentration in the package changes significantly. The process of performing measurement was repeated.
-Freshness retention days -2: The contents are taken out from two samples (packaging bodies), the number of E. coli is measured using each 3M Petri film (CC plate), and the average number of E. coli becomes 10 ² or more. The number of days was measured. It should be noted that multiple samples are prepared and the measurement is performed once a day.The measured sample is not used for the subsequent measurement because the gas concentration in the package changes significantly. The process of performing measurement was repeated.

Claims (9)

A package containing fruits and vegetables obtained by packaging fruits and vegetables in a packaging bag made of a synthetic resin film,
The rate of change in oxygen concentration in the package before and after the following treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less ,
A package containing fruits and vegetables having an oxygen permeation amount at 23° C. and 60% RH of ² cc/m ² ·day·atm or more and 50000 cc/m ² ·day·atm or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 50% RH. The package containing fruits and vegetables according to claim 1, wherein the water vapor transmission rate at 40°C is 2 g/m ² ·day or more and 400 g/m ² ·day or less. The inner area of the packaging bag per fresh produce 100g is 100 cm ² or more 5000 cm ² or less, vegetables and fruits containing packaging body according to claim 1 or 2.   The fruit and vegetables-containing package according to any one of claims 1 to 3, wherein the packaging bag has a through hole. The package with fruits and vegetables according to claim 4, wherein the number of the through-holes with respect to the inner area of the package is 1/m ² or more and 1500/m ² or less.   The package containing fruits and vegetables according to claim 4 or 5, wherein the through holes have an average pore diameter of 30 µm or more and 1100 µm or less.   The package containing fruits and vegetables according to claim 1, wherein the synthetic resin film has a thickness of 15 μm or more and 150 μm or less.   Sout/Sin>1.1, where Sout is the hole area on the outer surface of the fruit and vegetables freshness-keeping packaging bag and Sin is the hole area on the inner surface of the fruit and vegetables freshness-keeping packaging bag. A package containing fruits and vegetables according to any one of 4 to 7. A method of maintaining freshness of fruits and vegetables for packaging fruits and vegetables in a packaging bag made of a synthetic resin film,
The rate of change in the oxygen concentration in the package before and after the following treatment [(oxygen concentration after treatment)/(oxygen concentration before treatment)×100] (%) is 0.5% or more and 400% or less ,
A method for maintaining freshness of fruits and vegetables, wherein the fruits and vegetables are packaged so that the amount of oxygen permeation (cc/m ² ·day·atm) at 23° C. and 60% RH is 2 or more and 50000 or less.
Treatment: The package is stored for 3 days under the conditions of 20° C. and 90% RH.