JP2021103948A - Potato freshness keeping packaging container, potato package, potato freshness keeping method, and mold growth prevention method - Google Patents

Abstract

To provide a technique which can keep freshness of potato for a longer period of time.SOLUTION: A potato freshness keeping packaging container composed of a synthetic resin film, when potato is contained in the potato freshness keeping packaging container, has a water vapor permeating amount per 100 g of the potato at 40°C, 90%RH of 1.0 g/day atm or more and 3.3 g/day atm or less.SELECTED DRAWING: None

Description

The present invention relates to a freshness-preserving packaging container for potatoes, a potato package, a method for maintaining the freshness of potatoes, and a method for suppressing mold growth.

Fruits and vegetables continue to breathe even after harvesting, and the more active the breathing, the more likely it is to deteriorate. Respiration of fruits and vegetables is suppressed in an environment of moderate oxygen and carbon dioxide, which is different from the composition in the atmosphere. Under such conditions, when fruits and vegetables are stored, deterioration and ripening of fruits and vegetables are suppressed. Therefore, in recent years, as a method for packaging fruits and vegetables, a method for maintaining the freshness of fruits and vegetables by using a technique called MA (Modified Atmosphere) packaging has been used. This technology called MA packaging realizes an oxygen and carbon dioxide environment that is more suitable for storing fruits and vegetables than the atmosphere by adjusting the balance between the breathing rate of fruits and vegetables packaged in the packaging container and the gas permeation rate of the packaging container. (Patent Documents 1 to 3 and the like).

Japanese Unexamined Patent Publication No. 2-85181 Japanese Unexamined Patent Publication No. 9-252718 JP-A-2007-186248

In general, among fruits and vegetables, root vegetables such as potatoes may be stored refrigerated or stored at room temperature. The present inventor has found a new problem that the freshness of potatoes may not be sufficiently maintained when the potatoes are refrigerated and stored by using a conventional freshness-preserving technique called MA packaging.
Specifically, root vegetables such as potatoes that grow buried in the ground are different from fruits and vegetables that grow under the light of fruits, etc., because they are irradiated with light during storage, distribution, or storage after harvesting. , The respiratory volume tends to increase, and as a result, deterioration is likely to occur. When root vegetables such as potatoes were stored in a refrigerator, the occurrence of sprouting was reduced, but mold was generated and stable freshness could not be sufficiently maintained.

Therefore, as a result of diligent studies from the viewpoint of solving the new problem, the present inventor has found that it is effective to satisfy the specific water vapor permeation amount in the MA packaging container. That is, the present invention is based on a new finding that when the MA packaging container satisfies a specific water vapor permeation amount and when it does not, the freshness of the potato can be sufficiently maintained or not maintained. Yes, it uses a specific amount of water vapor permeation as an index.

According to the present invention
A freshness-preserving packaging container for potatoes made of synthetic resin film.
When potatoes are contained in the freshness-preserving packaging container for potatoes, the amount of water vapor permeation per 100 g of potatoes at 40 ° C. and 90% RH is 1.1 g / day · atm or more and 3.3 g / day · atm or less. Freshness-preserving packaging for potatoes is provided.

Further, according to the present invention, there is provided a potato package in which potatoes are contained in the freshness-preserving packaging container for potatoes.

Further, according to the present invention, there is provided a method for maintaining the freshness of potatoes, in which the potatoes are stored in the above-mentioned freshness-preserving packaging container for potatoes and stored in an environment of 10 ° C. ± 2 ° C.

Further, according to the present invention, there is provided a method for suppressing mold growth, in which potatoes are stored in the freshness-preserving packaging container for potatoes and stored in an environment of 10 ° C. ± 2 ° C.

According to the present invention, it is possible to provide a technique capable of maintaining the freshness of potatoes for a longer period of time.

Hereinafter, embodiments of the present invention will be described in detail. In the present specification, the term "abbreviation" means to include a range in consideration of manufacturing tolerances, assembly variations, etc., unless otherwise specified explicitly. Further, in the present specification, the notation of "a to b" in the description of the numerical range means a or more and b or less unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".

<Freshness preservation packaging container for potatoes>
The freshness-preserving packaging container for potatoes (hereinafter, also simply referred to as “packaging container”) of the present embodiment satisfies the following indicators.
Index: When potatoes are contained in a freshness-preserving packaging container for potatoes, the amount of water vapor permeation per 100 g of potatoes at 40 ° C. and 90% RH is 1.1 g / day · atm or more and 3.3 g / day · atm or less. ..
According to the packaging container of the present embodiment, by setting the water vapor permeation amount to the above lower limit value or more, the respiration and transpiration of the potato can be maintained appropriately, the weight reduction can be suppressed, and the freshness can be maintained. It is possible to prevent the humidity inside the packaging container from increasing due to the respiration and transpiration of the potatoes, which makes it easier for mold to grow.
On the other hand, the humidity around the packaging container tends to be high under refrigerated storage. However, according to the packaging container of the present embodiment, by setting the water vapor permeation amount to the above upper limit value or less, humid air can be introduced into the packaging container. It is possible to prevent intrusion and easy dew condensation inside the packaging container. As a result, the generation of mold can be suppressed. Further, when the amount of water vapor permeation is not more than the above upper limit value, the respiration of the potato can be appropriately maintained, the weight loss can be suppressed, and the freshness can be maintained.
When the potatoes are contained in the freshness-preserving packaging container for potatoes of the present embodiment, the amount of water vapor permeation per 100 g of potatoes at 40 ° C. and 90% RH is preferably 1.2 g / day atm or more. 0 g / day · atm or less, more preferably 1.5 g / day · atm or more, 2.8 g / day · atm or less, still more preferably 1.8 g / day · atm or more, 2.60 g / day · atm or less Is.
By setting the water vapor permeation amount to the above lower limit value or more, mold generation can be further suppressed, and by setting the water vapor permeation amount to the above upper limit value or less, mold generation can be suppressed while maintaining the weight residual ratio.

The amount of water vapor permeated can be measured by a method based on JIS Z0208 (cup method).

Further, the water vapor permeation amount of the packaging container controls the selection of the material of the synthetic resin film described later, the manufacturing method of the synthetic resin film, the layer structure of the synthetic resin film, the presence or absence of through holes, the average diameter and number of through holes, and the like. By doing so, it can be adjusted.

[Synthetic resin film]
The synthetic resin film is preferably transparent or translucent, and more preferably transparent, from the viewpoint that the potato can be visually recognized from the outside. In addition, it may be printed for the purpose of identifying potatoes.

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

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

From the viewpoint of price and physical properties, it is preferable to use a heat-sealable antifogging stretch polypropylene film, a low-density polyethylene film, a linear low-density polyethylene film, and a metallocene-catalyzed polyethylene.

The method for molding the synthetic resin film is not particularly limited, but methods such as extrusion, inflation, and calendar ring are used. When molding the synthetic resin film, additives such as an antifogging agent may be kneaded, or two or more kinds of resins may be blended, if necessary.
Further, the synthetic resin film may be subjected to stretching treatment, annealing, or the like, and may be further provided with a sealant layer. In particular, 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 multi-layer structure having two or more layers.

For example, from the viewpoint of obtaining sufficient strength for packaging potatoes, polyethylene is subjected to dry lamination, extruded lamination, and co-extrusion with respect to films such as unstretched polypropylene, stretched polypropylene, unstretched nylon, stretched nylon, and stretched polyester. It is preferable to use a multilayer film.

The average thickness of the synthetic resin film is preferably 10 μm or more and 150 μm or less, more preferably 15 μm or more and 100 μm or less, and further preferably 20 μm or more and 50 μm or less.
By setting the average thickness of the synthetic resin film to the above lower limit value or more, the oxygen permeation amount and the water vapor permeation amount can be more easily controlled, and the strength of the packaging container can be increased. On the other hand, by setting the average thickness of the synthetic resin film to the above upper limit value or less, the handleability of the packaging container can be improved, an appropriate amount of water vapor permeation and oxygen permeation can be imparted, and the production cost can be reduced.

[Through hole]
The packaging container of the present embodiment may have a through hole. This makes it possible to stably adjust the amount of water vapor permeation. It also makes it easier to effectively maintain the freshness of the potatoes.

The planar shape of the through hole may be, for example, a circle, a polygon, or a slit. The circular shape is not limited to a perfect circle, but includes a substantially circular shape. In addition to the circular shape, it may be semi-circular or crescent-shaped. 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 notch or a gap penetrating the synthetic resin film constituting the packaging container, and may be a straight line, a curved line, an L-shape, a cross mark, or the like, and the length thereof or the like is not particularly limited. ..

The average diameter of the through holes is preferably 30 μm to 1100 μm, more preferably 40 μm to 500 μm, and even more preferably 50 μm to 200 μm.
By setting the average diameter of the through holes to the above lower limit value or more, the amount of water vapor permeation and the amount of oxygen permeation are improved, and it becomes easy to maintain freshness while suppressing the generation of mold. On the other hand, by setting the average diameter of the through holes to be equal to or less than the above upper limit value, it is possible to prevent the entry of humid outside air and the tendency for mold to occur. In addition, it becomes possible to take in an appropriate amount of oxygen while minimizing the influence on the specific amount of water vapor permeated by the packaging container of the present embodiment.
The average diameter of the through hole is calculated from the opening area of the through hole with the through hole as a perfect circle.

The number of through holes is appropriately adjusted according to the size of the through holes and the amount of water vapor permeation, but from the viewpoint of obtaining a stable amount of water vapor permeation, one to one per ^{1000 cm 2 of the inner area of the packaging container.} The number is preferably 150, more preferably 2 to 80, and even more preferably 3 to 50.

The above-mentioned through holes may be formed in the synthetic resin film in advance when the packaging container is manufactured, may be formed after the synthetic resin film is formed in the container, and may be formed before and after the synthetic resin film is formed in the container. May be formed in.
As a method for forming the through hole, a known method can be used, and examples thereof include a processing method using a hot needle, a method of drilling with a laser beam, a method using a mold such as a roll cutter, and the like.

The oxygen permeation amount of the packaging container at 23 ° C. and 60% RH is preferably ² cc / m 2 · day · atm or more, and more preferably 5 cc / m ^{2 from the viewpoint of maintaining the respiration and freshness of the potato.}・ Day ・ atm or more, and more preferably 300 cc / m ²・ day ・ atm or more.
On the other hand, the oxygen permeation amount of the packaging container at 23 ° C. and 60% RH is preferably 50,000 cc / m ² · day · atm or less, and more preferably 10000 cc / m ² ·, from the viewpoint of maintaining the quality and freshness of potatoes. It is day · atm or less, and more preferably 7500 cc / m ² · day · atm or less.

Further, the oxygen permeation amount of the packaging container controls the selection of the material of the synthetic resin film described above, 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 and number of through holes. By doing so, it can be adjusted.

[Inner area]
Inner area of the packaging container of the present embodiment is preferably less potato 100g per 50 cm ² or more 1000 cm ^2, more preferably 70cm ² or more 500 cm ² or less, more preferably 90cm ² or more 200 cm ² or less. By setting the inner area of the packaging container within the above numerical range, it becomes easy to suppress the growth of mold while suppressing the weight loss of potatoes and maintaining the freshness.

[container]
Examples of the form of the freshness-preserving packaging container for potatoes include a bag-shaped container and a self-standing container. Of these, a bag shape is preferable from the viewpoint of stably exhibiting the freshness-maintaining effect. As the bag, a bag known as a bag for storing potatoes can be used. The method for manufacturing the bag is not particularly limited, and examples thereof include a method of fusing and sealing the synthetic resin film, a method of cutting the synthetic resin film and then heat-sealing.

<Potato packaging>
The potato package of the present embodiment is intended to contain potatoes in the above-mentioned freshness-preserving packaging container for potatoes. The potato capacity is appropriately set according to the size and weight of the potato and the inner area in the packaging container.

The potato package of the present embodiment is preferably sealed after containing the potatoes, and the opened portion may be heat-sealed, or a member such as a back sealing tape, a binding band, a rubber band, or a crimp may be used. You may use it.

In order to obtain a stable freshness-preserving effect, potatoes are preferably washed with water after harvesting to remove moisture. Alternatively, from the viewpoint of removing the influence of water on the potato as soon as possible, the water adhering to the potato may be removed by vacuum precooling or the like.

The weight retention rate of the potato package in the present embodiment is preferably 95% or more, more preferably 97% or more, and further preferably 98% or more. By setting such a value, the effect of maintaining the freshness of potatoes can be improved.

<How to keep potatoes fresh>
The method for maintaining the freshness of potatoes in the present embodiment is to store the potatoes in the above-mentioned freshness-preserving packaging container for potatoes and store them in an environment of 10 ° C. ± 2 ° C. As a result, the growth of mold can be suppressed and the freshness of potatoes can be maintained.
The environment of 10 ° C. ± 2 ° C. is a temperature suitable for maintaining the freshness of potatoes when the freshness-preserving packaging container for potatoes of the present embodiment is used.

<Mold growth control method>
The method for suppressing mold growth in the present embodiment is to store potatoes in the above-mentioned freshness-preserving packaging container for potatoes and store them in an environment of 10 ° C. ± 2 ° C. As a result, it is possible to suppress the growth of mold on potatoes.

Although the embodiments of the present invention have been described above, 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 by way of examples, but the content of the present invention is not limited to the examples.

<Example 1>
1) Preparation of synthetic resin film A Nylon 6 (manufactured by Ube Kosan Co., Ltd., UBE nylon (registered trademark) 1022B) and ethylene / vinyl alcohol copolymer resin (EVOH: manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Soanol 16DX) ) And was put into a T-die extruder to prepare a synthetic resin film A having a two-layer structure by a co-extrusion T-die method. The thickness of the obtained synthetic resin film A was 30 μm.
2) Preparation of packaging bag The synthetic resin film was cut into a cylindrical shape so that the layer made of nylon 6 of the obtained synthetic resin film A was on the inside, and the bottom of the bag was melted at 190 ° C. for 2 seconds. A packaging bag was prepared. The bag size (inner dimension) of the obtained packaging bag was 175 mm × 320 mm.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Example 2>
1) Preparation of synthetic resin film B A mixed material in which an antifogging agent (glycerin laurate: decaglycerin laurate, 97 parts by weight: 3 parts by weight) is added to 2.5% by weight of an ethylene / vinyl alcohol copolymer resin. Was coated on a biaxially stretched nylon film (manufactured by Unitica Co., Ltd., trade name "Emblem ONBC", thickness 25 μm) so as to be 800 mg / m ² (dry) to obtain a synthetic resin film B. The coating was performed by a gravure coat (drying temperature 100 ° C., drying time 10 seconds). The thickness of the obtained synthetic resin film B was 25 μm.
2) Preparation of packaging bag The obtained synthetic resin film B is cut, and two synthetic resin films are laminated so that the layer containing the antifogging agent is on the inside, and an impulse sealer (manufactured by Fuji Impulse Co., Ltd., FI-400Y) is laminated. A 10 mm wide heat-sealed portion was formed at 190 ° C. and a sealing time of 1 second by heat-sealing on three sides using -10 PK) to prepare a packaging bag. The bag size (inner dimension) of the obtained packaging bag was 175 mm × 320 mm.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Example 3>
1) Preparation of synthetic resin film B A synthetic resin film B was prepared in the same manner as in Example 2.
2) Preparation of packaging bag A packaging bag was produced in the same manner as in Example 2 except that the bag size (inner dimension) of the packaging bag was 225 mm × 370 mm.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Example 4>
1) Preparation of synthetic resin film B A synthetic resin film B was prepared in the same manner as in Example 2.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2, and seven holes having a diameter of 60 μm were perforated by laser processing in the entire obtained packaging bag.
3) Preparation of packaging The potatoes were housed in a packaging bag, and the area around 70 mm from the opening was sealed with a heat seal to obtain a packaging.

<Example 5>
1) Preparation of synthetic resin film B A synthetic resin film B was prepared in the same manner as in Example 2.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2, and two holes having a diameter of 130 μm were perforated by laser processing so as to be evenly distributed over the entire obtained packaging bag.
3) Preparation of packaging The potatoes were housed in a packaging bag, and the area around 70 mm from the opening was sealed with a heat seal to obtain a packaging.

<Comparative example 1>
1) Preparation of synthetic resin film C Polypropylene resin (manufactured by Japan Polypropylene Corporation, product number WFW5T) is melted, extruded from a T die at a temperature of 230 ° C., stretched 5 times in length × 9 times in width, and biaxially stretched polypropylene. A film (synthetic resin film C) was obtained. The thickness of the obtained synthetic resin film C was 25 μm.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Comparative example 2>
1) Preparation of Synthetic Resin Film A A synthetic resin film A was prepared in the same manner as in Example 1.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2. However, the thickness of the synthetic resin film A was set to 60 μm by doubling the amount of discharged resin per hour in the coextrusion T-die method.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Comparative example 3>
1) Preparation of Synthetic Resin Film A A synthetic resin film A was prepared in the same manner as in Example 1.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2. However, the thickness of the synthetic resin film A was set to 40 μm by increasing the amount of discharged resin per hour in the coextrusion T-die method by 1.3 times.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

<Comparative example 4>
1) Preparation of synthetic resin film B A synthetic resin film B was prepared in the same manner as in Example 2.
2) Preparation of packaging bag A packaging bag was prepared in the same manner as in Example 2. However, the bag size (inner size) of the packaging bag was changed to 275 mm x 420 mm.
3) Preparation of packaging body The potatoes were housed in a packaging bag, and the vicinity of 70 mm from the opening was sealed with a back seal (binding) to obtain a packaging body.

The following measurements and evaluations were carried out using the obtained package. The results are shown in Table 1.

<Measurement>
-Measurement of water vapor permeation amount at 40 ° C. and 90% RH The measurement was performed by a method conforming to JIS Z0208 (cup method). The measurement conditions were set at 40 ° C. and 90% RH. Further, the weighing was carried out under the conditions of 23 ° C. and 50% RH. The unit is g / (day, atm, potato 100 g).
If the method conforming to JIS Z0208 (cup method) cannot be used because the amount of water vapor permeated by the synthetic resin film is too large, calcium chloride is heat-sealed in a 50 mm x 100 mm (inner size) bag instead of the cup. The amount of water vapor permeation was calculated from the change over time in the weight of this bag. In this case, the storage period of the bag was set within the range in which calcium chloride did not completely absorb moisture.

-Measurement of average hole diameter (μm) of through holes Using a microscope (manufactured by KEYENCE, VH-6300), the opening area of the inner surface of the packaging bag was measured for 5 holes. Assuming that the perforated portion is a perfect circle, the diameter was calculated from the perforated area, and the average diameter was calculated.

<Evaluation>
Each of the potato-containing packages obtained above (all within the range of 700 to 900 g of potato content) was stored at 10 ° C. for 23 days. Then, the potatoes were taken out from the package, and the "mold occurrence rate (%)", "sprouting rate (%)" and "weight residual rate (%)" were measured by the following methods, respectively.
-Mold occurrence rate (%): The presence or absence of mold was visually observed, and the number of potatoes in which mold growth was observed with respect to the total number of potatoes was calculated and used as the mold occurrence rate (%).
-Germination rate (%): The presence or absence of germination was visually observed, and the number of potatoes in which germination was observed was calculated with respect to the total number of potatoes, and used as the germination rate (%).
-Weight residual ratio (%): The ratio (%) of the weight (g) of the potato after storage to the weight (g) of the potato before storage was calculated.

Claims (9)

A freshness-preserving packaging container for potatoes made of synthetic resin film.
When potatoes are contained in the freshness-preserving packaging container for potatoes, the amount of water vapor permeation per 100 g of potatoes at 40 ° C. and 90% RH is 1.1 g / day · atm or more and 3.3 g / day · atm or less. Freshness-preserving packaging for potatoes. The freshness-preserving packaging container for potatoes according to claim 1, wherein the thickness of the synthetic resin film is 10 μm or more and 150 μm or less. The potatoes the inner area of the potato for freshness packaging containers per 100g is 50 cm ² or more 1000 cm ² or less, potatoes for fresh-keeping packaging container according to claim 1 or 2. The freshness-preserving packaging container for potatoes according to any one of claims 1 to 3, wherein the freshness-preserving packaging container for potatoes has a through hole. The freshness-preserving packaging container for potatoes according to claim 4, wherein the number of through holes is 1 or more and 150 or less with respect to ^{an inner area of 1000 cm 2 of the freshness-preserving packaging container for potatoes.} The freshness-preserving packaging container for potatoes according to claim 4 or 5, wherein the average hole diameter of the through holes is 30 μm or more and 1100 μm or less. A potato package in which potatoes are contained in the freshness-preserving packaging container for potatoes according to any one of claims 1 to 6. A method for maintaining the freshness of potatoes, wherein the potatoes are stored in the freshness-preserving packaging container for potatoes according to any one of claims 1 to 6 and stored in an environment of 10 ° C. ± 2 ° C. A method for suppressing mold growth, wherein the potatoes are stored in the freshness-preserving packaging container for potatoes according to any one of claims 1 to 6 and stored in an environment of 10 ° C. ± 2 ° C.