JPH06284860A - Method for preserving freshness of welsh onion - Google Patents

Abstract

PURPOSE:To provide the subject excellent method suitable for welsh onion, useful as a means for seeking a new environment freshness Welsh onion. CONSTITUTION:Welsh onion is put into a closed or semi-closed vessel and a carbon dioxide generator and/or oxygen generator is then included in the vessel, and the Welsh onion is preserved in such an environment as to be >=2wt.% in oxygen concentration and >=4wt.% in carbon dioxide concentration (in both cases, nitrogen is a balancing gas).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining freshness of leeks.

[0002]

2. Description of the Related Art The fruits and vegetables that we use as foods are not only diverse in their roots, stems, leaves, flowers, fruits and seeds, but also in the same areas. The level of heat utilization is also very different. For example, in fruit and vegetables, young peas and cucumbers use young fruits, and tomatoes use ripe fruits. Further, it is no exaggeration to say that these vegetables and leaf vegetables such as leeks have different physiology, and vegetables have different physiology. Therefore, when considering the preservation of freshness of fruits and vegetables, it is necessary to grasp the physiology of individual fruits and vegetables and to find a method of keeping the freshness that matches the physiology of individual fruits and vegetables.

[0003] In recent years, as the table has become richer, the consumption of leeks as a condiment has increased, the number of cultivated areas has increased year by year, and the number of plant cultivations has also increased. ing. However, since green onions have a high growth rate, they have high metabolic activity and are severely deteriorated in quality, so they are a category of vegetables that are extremely difficult to handle during transportation and storage.

The deterioration of the quality of leeks is apt to appear as yellowing, wilting and rotting in appearance, which makes it extremely difficult to transport and store, especially during the period from spring to autumn when the temperature is high.
Development of a highly effective freshness preservation method is awaited.

Further, in the conventional cold transportation in which the leeks are pre-cooled and then packed in a cold container, the leaf temperature of the leeks is hollow, so that the product temperature easily rises, and the effect varies. Many, it is very difficult to maintain stable quality.

On the other hand, the transportation quantity of leeks has been increasing year by year, and development of a freshness keeping method having a packaging form suitable for mass transportation and having a high freshness keeping effect is awaited.

[0007]

The problem to be solved by the present invention is to solve the above-mentioned problems in conventional freshness preservation of leeks. That is, conventional freshness preservation of leeks has been carried out in accordance with general measures for keeping freshness of fruits and vegetables like other fruits and vegetables.

The present invention is based on the behavior relating to keeping freshness of leek, especially oxygen-carbon dioxide concentration (under nitrogen balance: nitrogen gas is used as balance gas), and a new environment as a means for keeping freshness of leek. Therefore, the present invention seeks to develop an excellent freshness-keeping method suitable for leeks which can eliminate the conventional drawbacks. The green onions referred to here mean general green onions such as large green onions, small green onions, scallions, red chives, leeks, and green onions.

[0009]

[Means for Solving the Problems] This problem is to put leeks in a closed or semi-closed container and enclose a carbon dioxide generating agent and / or an oxygen generating agent, and rapidly increase the oxygen concentration to 2% or more. In a gas environment with a concentration of 4% or more (under nitrogen balance), more preferably in the high temperature period above 30 ° C in summer, the oxygen concentration is 6% or more and the carbon dioxide concentration is 9%.
It is solved by keeping the above gas environment.

The present inventor has made repeated studies by overcoming the above problems and finding a better method of maintaining freshness by storing leeks in a gas environment with various oxygen concentrations and carbon dioxide concentrations in the nitrogen balance. .

As a result, it has been found that by keeping the oxygen concentration at 2% or more and storing the green onions in an environment in which the carbon dioxide concentration is raised to 4% or more, extremely good freshness can be maintained.

[0012] In particular, in the case of transportation in the high temperature period of more than 30 ° C in summer, it is preferable to keep the oxygen concentration at 6% or more and the carbon dioxide concentration at 9% or more in the gas environment, and the leek. It has been found that the preservation of syrup can prevent the deterioration of leeks and maintain good freshness.

The effect of this high carbon dioxide is recognized even under the high oxygen concentration of about 20 to 22% which is almost equal to the oxygen concentration in the air. However, when the oxygen concentration is lower than 2%, a particularly high carbon dioxide concentration promotes the generation of acetaldehyde and ethyl alcohol, causes wilting, spoilage, and nasty odor, which is contrary to the preservation of freshness. This decrease is remarkable especially when the temperature exceeds 30 ° C. as in the high temperature season of summer, and it has been found that increasing the oxygen concentration to 6% or more is particularly effective for preventing this decrease.

[0014] As a result of these various studies, it was found that the respiration rate of leeks is suppressed under the environment of low oxygen concentration, but the leaf yellowing suppression effect is small. On the other hand, when the carbon dioxide concentration is increased, the effect of suppressing yellowing becomes remarkable and the respiratory volume is also suppressed. However, it has been found that when the carbon dioxide concentration is increased under a low oxygen concentration condition such that the oxygen concentration falls below 2%, the oxygen uptake amount is excessively suppressed, anaerobic respiration becomes severe, and the tissue is deteriorated.

Therefore, it can be considered that it is extremely difficult to obtain the effect by the conventional nitrogen gas substitution packaging of leeks and Chinese chive. Also, the same, oxygen concentration 2% or more, carbon dioxide concentration 4% or more, more preferably in the high temperature period of 30 ℃ in summer, oxygen concentration 6% or more, carbon dioxide concentration 9%
Even if the above gas environment can be achieved by simple MA (Modified Atmosphere) packaging that uses only plastic film, the MA packaging wraps the fruits and vegetables in the plastic film, and the carbon dioxide and oxygen generated by the respiratory exhaustion of the fruits and vegetables inside. Since it takes time to build and consumes nutrients containing fruits and vegetables, it contains a carbon dioxide generating agent or an oxygen generating agent from the beginning of packaging of fruits and vegetables. As a result, the method of the present invention for rapidly establishing the gas environment has a difference in the freshness preservation effect.

[0016]

The principle of the method of the present invention is as follows. A green onion is placed in a closed or semi-closed container as described above, and a carbon dioxide generating agent and / or an oxygen generating agent is included therein. It is to keep allium in a gas environment having a carbon dioxide concentration of 4% or more, particularly preferably in a gas environment having an oxygen concentration of 6% or more and a carbon dioxide concentration of 9% or more in the high temperature period of summer. The mode as a typical specific example is as follows. That is,

The leeks are placed in a closed or semi-closed container to contain a carbon dioxide generating agent or an oxygen generating agent.

Loose semi-closed container made of plastic film for leek or semi-closed container made of perforated plastic film pack or closed container made of plastic film having oxygen gas permeability of 8000 ml / m ² · 1 atm · 24 h or more. To contain a carbon dioxide generating agent or further an oxygen generating agent.

A semi-closed container made of Styrofoam for leeks, or having an oxygen gas permeability of 3000 ml / isobar under constant pressure.
It is placed in a closed container made of expanded polystyrene having a m ² · 24 h or more and a carbon dioxide generating agent is encapsulated therein, or an oxygen generating agent is further encapsulated therein.

Leeks are placed in a corrugated cardboard case which is combined with a plastic film, and a carbon dioxide generating agent is included therein, or an oxygen generating agent is further included therein.

The leek has a carbon dioxide gas permeability of 100.
000 ml / m ² · 1 atm · 24h or less, preferably 100
000 to 10000 ml / m ² · 1 atm · 24 h in a hermetically sealed package made of a plastic film and encapsulating an oxygen generating agent.

In the above embodiment, the leeks are placed in a closed container or a semi-closed container, and the carbon dioxide generating agent or the oxygen generating agent is contained alone, or both the carbon dioxide generating agent and the oxygen generating agent are further contained. . The basic feature of this embodiment is the ability to generate carbon dioxide in accordance with the gas permeability of the container or the degree of gas flow, by putting leeks in single or composite containers (including film packaging) of plastics of various gas permeability. Of different oxygen content, or of different ability to generate oxygen, or both of carbon dioxide-producing component and oxygen-producing component. It is intended to adjust the concentration.

At this time, the plastic used for the container is usually high-density polyethylene (density 0.93 or more, HDP
E), low density polyethylene (density less than 0.93, LDP
E), polyamide (PA), polyester (PET),
Butadiene rubber (BR), ethylene vinyl acetate copolymer (PVAc), polypropylene (PP), polystyrene (PS), etc., used as a molded single container or a composite container, a molded foam container, or a bag-shaped container in some cases. Good. Further, perforation processing or the like may be performed.

The semi-closed container mainly means the structure or shape of the container and does not mean gas permeability. More specifically, in view of the gas permeability of the material of the container, the structure or shape of the container is a partially vacant structure or shape, and not only the container but also packaging with a film, a sheet, or the like is included.

Any oxygen generator may be used as long as it can generate oxygen, for example, sodium percarbonate, sodium persulfate,
Specific examples of sodium peroxide, potassium peroxide and the like can be mentioned. The means for inclusion is not particularly limited as long as it can generate a desired amount of oxygen.

Any carbon dioxide generator may be used as long as it can generate carbon dioxide. Specific examples thereof include a combination of calcium carbonate and an organic acid or sodium bicarbonate and an organic acid, or an inorganic acid, or an inorganic salt. And an inorganic filler or the like may be included, and the inclusion means thereof is the same as in the case of the oxygen generator. Examples of organic acids and inorganic acids include citric acid, fumaric acid, metaphosphoric acid and the like. Examples of inorganic acid salts include barium sulfate and sodium sulfate. Examples of the inorganic filler include clay and zeolite. These inorganic acid salts and inorganic fillers control the generation rate.

The mode (1) is one of the concrete forms of the mode (1), and the basic is that the oxygen concentration is set to a predetermined value by the permeation or circulation of air, and carbon dioxide, which is insufficient in the air, is separately generated, It is intended to adjust the carbon dioxide concentration to a predetermined value.

Alternatively, when the inflowing air alone is insufficient in oxygen, an oxygen generating agent is also used to adjust the carbon dioxide concentration and the oxygen concentration to predetermined values.

For this reason, a perforated plastic film through which air can flow is used or loose sealing is performed. The oxygen gas permeability is 8000.
In a closed container made of a film of ml / m ² · 1 atm · 24 h or more, almost necessary amount of oxygen will be permeated from the outside air into the container, which is also one of the embodiments of the present invention. You can Of course, if there is a shortage, an oxygen generator may be included.

LDPE, PVAc, HDPE, PP, PET, and the like can be used as plastics for loosely sealed containers or perforated containers by this method.
PA, PS, BR, etc. can be used.

Oxygen gas permeability used in a closed container is 800
The plastic film of 0 ml / m ² · 1 atm · 24 h or more can be exemplified by those made of LDPE, EVAc, HDPE, BR, etc., and the container and various gas generating agents are the same as in the case of the above embodiment.

The embodiment is one of the concrete forms of the embodiment, and is basically the same as the embodiment, except that the semi-closed container or the closed container is a container formed by foaming polystyrene foam beads or a foamed polystyrene bead. A container prepared by thermoforming or pasting a polystyrene sheet is used, and a carbon dioxide generating agent or further an oxygen generating agent is included therein. A resin foam, including expanded polystyrene, is also one form of a film formed by adhering a resin thin film that forms bubbles, and is one of the specific forms of the embodiment.

As a concrete example of the hermetically sealed container here, there can be exemplified a container which can be tightly covered with no gap between the container and the lid, and the oxygen permeation amount when the oxygen gas is enclosed in the container is 3
Any container with a capacity of 000 ml / m ² · 24 h or more may be used.

On the other hand, a specific example of the semi-closed container may be one in which a gap is provided between the container and the lid, one in which an opening is provided in a part of the container, or a combination of both. . Essentially, any material may be used as long as it meets the above-mentioned conditions in addition to polystyrene, and foamed plastics such as polyurethane foam mentioned above can be appropriately selected and used. The container itself of this embodiment is a container that has been often used for distribution from the past, and is used for mass transportation. In addition, the various gas generating agents to be included are the same as those in the case of (1).

The embodiment is one of the concrete forms of the embodiment, in which a composite of a corrugated cardboard case and a plastic film is used as a container, and a carbon dioxide generating agent or further an oxygen generating agent is included. As the plastic film to be composited, those listed in can be appropriately selected and used.
The form of the composite cardboard case is JIS-Z-
The most common type 0201 or 0 defined in 1507
Basically, any type can be appropriately selected and used, such as 206, 0212, 0303, and 0309 types, which are relatively easily sealed, or boxes which are assembled from a single uncorrugated cardboard sheet. Also, the sealing method is tape, glue,
A wire stitcher or the like can be appropriately selected and used. This mode is a packaging form that is easy to handle and work, and has an excellent advantage as a mass transport container. Also in this case, the carbon dioxide generating agent and the oxygen generating agent listed above can be used.

In the mode (1), carbon dioxide is included in the container, and oxygen is generated from the generator to adjust the concentration of each of them to a predetermined value. As plastic, HDPE, EVAc, LDPE, BR, PP, PS
Etc. The generator is the same as that of.

Needless to say, in the present invention, a higher effect can be expected by using a scavenger for ethylene which is closely related to the yellowing of leeks. As the ethylene remover used at this time, conventionally known ones are widely used, and other ethylene remover newly developed by the present applicant may be used. This new ethylene scavenger is disclosed, for example, in Japanese Patent Application Laid-Open Nos. 4-84865, 4-141070, and Japanese Patent Application No. 2-86688.
It was disclosed in the issue.

[0038]

EXPERIMENTAL EXAMPLE The present invention will be described below with reference to experimental examples.

[0039]

[Experimental Example 1] The amount of oxygen uptake and the condition of leaves at the end of storage when the small onions were stored (20 ° C and 30 ° C for 30 days) under various gas environments shown in Table 1 were investigated. The results are shown in Table 1. However, nitrogen was used as the balance gas in each treatment zone. The unit of oxygen uptake in the table is 1 / kgFW / 3da
ys.

[0040]

[Table 1]

The evaluations in Table 1 are based on the following criteria. ◎: Very good ○: Good △: Normal □: Slightly bad (commercial value limit) ×: Bad

[0042]

[Experimental Example 2] High density of 15 μm (density: 0.935)
Polyethylene (HDPE) film, 25 μm thick low density (density: 0.915) polyethylene (LDPE), 5
5 μm thick LDPE film, 25 μm thick ethylene vinyl acetate copolymer (EVAc) film (ethylene: 83
%), 15 μm thick butadiene rubber (BR) film, and perforated 55 μm thick LDPE
Table 2 shows the gas composition in the film and the condition of leaves at the end of storage when small onions were stored (30 ° C, 3 days) using 6 types of films and carbon dioxide and oxygen generators.
Shown in. The gas permeability of the film used is shown below.

HDPE 15 μm O ₂ 13000 ml / m ² · 1 atm · 24 h CO ₂ 45000 ml / m ² · 1 atm · 24 h LDPE 25 μm O ₂ 7100 ml / m ² · 1 atm · 24 h CO ₂ 28700 ml / m ² · 1 atm · 24 h LDPE 55 μm O ₂ 4200 ml / m ² · 1 atm · 24 h CO ₂ 14200 ml / m ² · 1 atm · 24 h EVAc 25 μm O ₂ 13500 ml / m ² · 1 atm · 24 h CO ₂ 79000 ml / m ² · 1 atm · 24 h BR 15 μm O ₂ 30000 ml / m ² · 1 atm ・ 24h CO ₂ 130000ml / m ²・ 1atm ・ 24h

Perforation processing 55 μmL DPE
Film: A film in which 30 holes of 0.5 mmφ are opened per square meter

[0045]

[Table 2]

The evaluations in Table 2 comply with the following criteria. ◎: Very good ○: Good △: Normal □: Fair (commercial value limit) ×: Poor

[0047]

[Experimental Example 3] 20 μm thick stretched polypropylene (OP
P) Table 3 shows the gas composition in the film and the leaf condition at the end of storage when the onion was stored (0 ° C., 7 days) using the film and the carbon dioxide generator. The gas permeability of the film used is shown below.

OPP 20 μm O ₂ 2400 ml / m ² · 1 atm · 24 h CO ₂ 7700 ml / m ² · 1 atm · 24 h

[0049]

[Table 3]

The evaluations in Table 3 are based on the following criteria. ◎: Very good ○: Good △: Normal □: Slightly bad (commercial value limit) ×: Bad

[0051]

[Experimental Example 4] 0201 type ordinary cardboard case, 30 μm
Gas composition in the case of 0201 type film laminated corrugated cardboard case where a thick LDPE film is laminated on the front liner, and Styrofoam case are filled with scallions and stored (15 ° C, 4 days) by appropriately using carbon dioxide generator Table 4 shows the condition of leaves at the end of storage. In addition, tape I-shape was used to seal the cardboard case.

Here, the above-mentioned corrugated cardboard case is a normal corrugated cardboard case and a film laminated corrugated cardboard case.
-220 x SCP-125 x A-220 A of the base paper configuration
F was used. The film was laminated in a sandwich form between the corrugated board liner layers (A-18).
0 + 30 μmL DPE + craft 40).

[0053]

[Table 4]

The evaluation in Table 4 complies with the following criteria. ◎: Very good ○: Good △: Normal □: Slightly bad (commercial value limit) ×: Bad

[0055]

[Experimental Example 5] The amount of oxygen taken up when the Chinese chive was stored (20 ° C and 30 ° C for 3 days) under various gas environments shown in Table 5 and the condition of leaves at the end of the storage were investigated. The results are shown in Table 5.
Shown in. However, nitrogen was used as the balance gas in each treatment zone. The unit of oxygen uptake in the table is 1 / kgFW / 3days
Is.

[0056]

[Table 5]

The evaluation in Table 5 complies with the following criteria. ◎: Very good ○: Good △: Normal □: Slightly bad (commercial value limit) ×: Bad

[0058]

[Experimental Example 6] 20 μm thick low density (density: 0.915)
Two kinds of films, polyethylene (LDPE) and oriented polypropylene (OPP) film with a thickness of 20 μm, and a carbon dioxide generator and an oxygen generator were used to store Chinese chive (25 ° C, 3 ° C).
Table 6 shows the composition of gas in the film and the condition of the leaves at the end of storage. The gas permeability of the film used is shown below.

LDPE 20 μm O ₂ 8500 ml / m ² · 1 atm · 24 h CO ₂ 38000 ml / m ² · 1 atm · 24 h OPP 20 μm O ₂ 2400 ml / m ² · 1 atm · 24 h CO ₂ 7700 ml / m ² · 1 atm · 24 h

[0060]

[Table 6]

The evaluation in Table 6 complies with the following criteria. ◎: Very good ○: Good △: Normal □: Slightly bad (commercial value limit) ×: Bad

[0062]

As described above, according to the method of the present invention, the freshness of leeks can be maintained extremely well, and it is extremely useful during storage or distribution at room temperature.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Sako ▼ Kazuhiro Tada 8-28 Kuwatacho, Ibaraki City Rengo Co., Ltd. Ibaraki Dormitory (72) Inventor Yoshinori Ono 8-28 Kuwatacho Ibaraki City Rengo Co., Ltd. Ibaraki Dormitory Co., Ltd. (72) Inventor Motoi Shimizu 5-39-24 Takayanagi, Neyagawa City

Claims (6)

[Claims] 1. Put onions into a closed or semi-closed container,
At least one of a carbon dioxide generating agent and an oxygen generating agent is included, and the onions are kept in an environment of oxygen concentration of 2% or more and carbon dioxide concentration of 4% or more (both are balance gas nitrogen). How to maintain freshness of allium. 2. The method for maintaining freshness of green onions according to claim 1, wherein the oxygen concentration is 6% or more and the carbon dioxide concentration is 9% or more when the environment is 30 ° C. or more. 3. A loose semi-closed container made of a plastic film for leek or a semi-closed container made of a perforated plastic film pack, or a plastic film having an oxygen gas permeability of 8000 ml / m ² · 1 atm · 24 h or more. The method for keeping freshness of green onions according to claim 1, wherein the method is carried in a closed container and a carbon dioxide generating agent is included therein, or an oxygen generating agent is further included therein. 4. A green onion is placed in a semi-sealed container made of expanded polystyrene or a closed container made of expanded polystyrene having an oxygen gas permeability of 3000 ml / m ² · 24 h or more, and a carbon dioxide generating agent is included therein, or further oxygen generation is carried out. The method for keeping freshness of leek according to claim 1, wherein the agent is encapsulated. 5. A leek is placed in a plastic film composite cardboard case and a carbon dioxide generating agent is included, or
Alternatively, the method for keeping freshness of leek according to claim 1, wherein the method further comprises encapsulating the oxygen-generating agent and then sealing. 6. A leek has a carbon dioxide gas permeability of 1000.
Put in an airtight container of 00 ml / m ² · 1 atm · 24h or less, enclose the oxygen generating agent, the oxygen concentration in the container is 6% or more,
The method for keeping freshness of leek according to claim 1, wherein the carbon dioxide concentration is maintained at 9% or more.