JPH03216148A - Perishable food storage device - Google Patents

Abstract

PURPOSE:To obtain the title device of decomposing ethylene produced from vegetables and fruits in a storage chamber with ozone, suppressing respiratory action of vegetables and fruits and maintaining freshness of vegetables and fruits by constituting a gas atmosphere made of a specific mixed gas containing ozone in the storage chamber. CONSTITUTION:First, a gas atmosphere in a storage chamber of vegetables and fruits consists of a mixed gas of an adjusting gas containing at least nitrogen, CO2 and oxygen and ozone and the composition of the adjusting gas is set at a composition having a larger amount of nitrogen and CO2 than those of volume constituent ratio of air and a smaller amount of oxygen. Then the vegetables and fruits put in the storage chamber are brought into contact with the mixed gas to decompose ethylene evolving from vegetables and fruits with ozone and to maintain freshness of vegetables and fruits.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a fruit and vegetable storage device that can smoothly maintain the freshness of fruits and vegetables over a long period of time.

, 1K technology> In general, C mainly stores fruits and vegetables such as canned vegetables.
In storage A, the storage room is kept at a low temperature and the gas is controlled to reduce oxygen and increase carbon dioxide, suppressing the respiration of fruits and vegetables and increasing their storage capacity. On the other hand, fruits and vegetables themselves emit ethylene gas as they ripen, but in the closed space of a storage room, the ethylene concentration tends to be excessive, leading to the aging of fruits and vegetables and the risk of decreasing their freshness. There is.

Therefore, as a conventional technology to maintain the freshness of fruits, vegetables, meat, etc. using ozone, as shown in Japanese Patent Application Laid-open No. 133971/1982, ozone is used to maintain the freshness of fruits, vegetables, meat, etc. using substances containing fine porous materials such as zeolite, Oya stone, and activated carbon. There is one in which the inner wall of the storage is made oval and the fine porous material is treated with oxygen by applying ozone.

The related art attempts to maintain the quality of fruits and vegetables by having a fine porous material adsorb and remove harmful gases such as ethylene gas generated from fruits and vegetables or ammonia gas generated from rotting meat.

Problems to be Solved by the Invention> However, in practice, the above prior art has the following problems.

(1) Removal of ethylene gas, etc. is through gas adsorption, so when the adsorption of gas to the porous material reaches a saturated state, no further adsorption occurs, and there is a risk of desorption, which naturally occurs. There are limits to adsorption capacity.

(2) Even if it can adsorb ammonia gas, etc. produced by spoilage, its ability to suppress spoilage itself is weak, so there is a limit to its ability to maintain freshness.

The technical objective of the present invention is to effectively maintain the freshness of fruits and vegetables over a long period of time. Means for Solving the Problems> Based on the oxidizing effect of ozone and the bactericidal effect caused by it, the present inventor has discovered that when ozone is applied to ethylene, the removal of ethylene and the sterilization of fruits and vegetables are organically effected. Focusing on the mutual understanding, this invention was conceived and completed.

That is, in the present invention, the gas atmosphere in the storage chamber is formed with a mixed gas of ozone and a regulating gas containing at least nitrogen, carbon dioxide, and oxygen, and the air body f! In addition to setting nitrogen and carbon dioxide gas to be higher and oxygen to be lower than the composition ratio, the mixed gas is brought into contact with the fruits and vegetables stored in the storage room, and the ethylene generated from the fruits and vegetables is decomposed by ozone to maintain the freshness of the fruits and vegetables. This is a fruit and vegetable storage device characterized by the following configuration.

The above-mentioned fruits and vegetables basically refer to fresh foods such as vegetables and fruits that emit ethylene gas by themselves. The composition of the FJ regulating gas among the above atmospheric mixed gases is such that the volume composition ratio of air (nitrogen 78.1%, carbon dioxide 0.03%, oxygen 20 .9%), the amount of nitrogen and carbon dioxide gas is set to be higher, and the amount of oxygen is set to be lower, as shown below.

N290-95% 7/022-8%/CO23-5% However, each component of the above atmospheric gas includes both those introduced into the storage room from the outside and those generated from fruits and vegetables inside the storage room. .

In addition, the concentration of ozone added to the entire mixed gas is 0.01 to 20 ppm from the viewpoint of effectiveness and safety of the sterilizing effect.
is preferred.

■The atmospheric gas in the storage room is composed of a mixed gas of ozone and a conditioning gas containing at least nitrogen, carbon dioxide, and oxygen.
Since the amount of nitrogen and carbon dioxide gas is set to be higher than the volume ellipse ratio of air, and the amount of oxygen is set to be lower than that of air, and the fruits and vegetables are placed in the mixed gas atmosphere, the respiration effect of the fruits and vegetables is suppressed.

■On the other hand, fruits and vegetables produce their own ethylene as they mature, but the ethylene produced in the storage chamber by the ozone is oxidized to ethylene oxide, reducing the ethylene concentration.

As a result, fruits and vegetables are prevented from aging due to (1) and (2) above, and their freshness is maintained at a high level.

In addition, microorganisms such as bacteria, yeast, filamentous fungi, and viruses attached to fruits and vegetables are sterilized by ozone and ethylene oxane, and the spoilage of fruits and vegetables caused by microorganisms is effectively suppressed.

In particular, ozone exhibits effective sterilizing power against spore-forming bacteria such as Bacillus and Clostridium.

In addition, -a, since ozone is unstable, it easily decomposes into oxygen molecules and oxygen atoms over time, and after the active oxygen atoms act on the cell walls, cell membranes, enzymes, etc. of microorganisms and sterilize them. Since only oxygen molecules remain, there is no problem of toxicity of fruits and vegetables due to residual ozone.

<Effects of the invention> (1) ■ Ethylene, which causes the aging of fruits and vegetables, is oxidized to ethylene oxide using ozone, thereby reducing the ethylene concentration and preventing the aging of fruits and vegetables.■ Microorganisms attached to fruits and vegetables are removed using ozone. and sterilizes fruits and vegetables with ethylene oxide to suppress spoilage of fruits and vegetables caused by microorganisms; ■ suppresses the respiration of fruits and vegetables in a controlled mixed gas atmosphere to prevent aging of fruits and vegetables, thereby maintaining the freshness of fruits and vegetables for a long period of time. It can be held high for a long time.

(2)■ Ozone reduces ethylene concentration and prevents fruit and vegetables from aging.

■Ethylene oxide, produced by oxidizing ethylene with ozone, sterilizes microorganisms attached to fruits and vegetables.

Therefore, by using ozone as one of the components of the atmospheric gas in the storage room, the above two effects (1) and (2) can be realized simultaneously and organically, making it possible to maintain the freshness of fruits and vegetables more efficiently.

(3) Conventional technology that adsorbs and removes ethylene has a limited ability to adsorb ethylene, and has a weak ability to inhibit spoilage itself, so there is a natural limit to maintaining the freshness of fruits and vegetables, but with the present invention, By removing ethylene with acid, the problems of the prior art can be overcome.

<Example> Hereinafter, the fruit and vegetable storage device of the present invention will be explained, and the experimental results of the change in ethylene concentration over time when stored with this mixed gas will be described, using the case where the fruits and vegetables are stored without using ozone as a comparative example. .

FIG. 1 is a schematic explanatory diagram of a fruit and vegetable storage device showing a first embodiment, in which an N2 gas supply line 1 and a mixed gas supply line 2 are introduced into a storage chamber 3, and an atmospheric gas discharge line 4 is It is derived from the storage room 3 and configured.

The N2 gas supply line 1 connects nitrogen supplied from an adsorption/separation type nitrogen generator 5 to the storage chamber 3 via a nitrogen holder 6 and a flow rate adjustment device 7.

The adsorption separation type nitrogen generator 5 includes an air compressor 8
After the air pumped in is stored in an air tank 10, it is passed through a nitrogen generation tower 11 filled with molecular sieves to adsorb and separate only nitrogen from the air to obtain nitrogen gas.

Note that the nitrogen generator 5 may be a simple nitrogen gas cylinder or may be a combination of a liquefied nitrogen gas cylinder and a vaporizer.

The mixed gas supply line 2 is the ozone gas supply line 1.
2 and a regulating gas supply line 13 are joined to a mixer 14, and a mixed gas line 15 led out from the mixer 14 is connected to the storage chamber 3.

The ozone gas supply line 12 connects a silent discharge type ozone generator 16 that flows oxygen-containing gas between electrodes and generates ozone by applying an AC high voltage to the mixer 14 via a flow control device 17. It's ours.

Further, the adjustment gas supply line 13 is connected to a gas regulator 18.
The air line 20 from the air compressor 19 and the atmospheric gas discharge line 4 from the storage chamber 3 are joined together,
The gas regulator 18 is connected to the mixer 14 via a flow rate regulator 21.

The gas regulator 18 is composed of a carbon dioxide scrubber 22 and an oxygen converter 23 combined in series. At the same time, (1) the oxygen converter 23 causes the oxygen in the storage chamber 3 to act on the propane gas (that is, burns the propane) and converts it into carbon dioxide gas.

A part of the ethylene generated from fruits and vegetables is led to the gas regulator 18 through the atmospheric gas discharge line 4, burned and removed by the oxygen converter 23, and adsorbed and removed by the scrubber 22.

The air from the airline 20 is used to supply nitrogen and oxygen to the mixer 14 and to assist combustion in the oxygen converter 23.

However, the filler for the carbon dioxide scrubber 22 may be an alkaline agent such as caustic soda or slaked lime, or an absorbent such as water.

The carbon dioxide gas and excess air discharged from the gas regulator 18 and the oxygen separated from the air by the nitrogen generator 5 are sucked into the gas discharge line 2 by the suction action of the vacuum pump 24.
Excluded from the storage device from 7.2S.

Further, the storage chamber 3 is maintained in a refrigerated atmosphere by a refrigerator 25, and the pressure difference between the outside air and the inside of the storage chamber 3 is adjusted by an air pressure bag 26.

Therefore, the functions of the storage device described above will be described.

(1) N2 is supplied from the N2 gas supply line 1 into the storage chamber 3 to replace 02 in the storage chamber 3 with N2 to suppress the [IT absorption effect of fruits and vegetables.

(2) A mixed gas of N 2 , 0 2 and O is supplied from the mixed gas supply line 2 .

As mentioned above, the supply of N2 is to reduce the oxygen concentration in the storage room 3, and the supply of 02 is to maintain the inside of the storage room 3 at a predetermined low concentration so that fruits and vegetables do not suffer from hypoxic damage. This is to keep it in place.

Further, as mentioned above in the section on effects, O has the following effect.

■ Oxidizes ethylene, which is produced as a so-called ripening hormone from fruits and vegetables themselves, into ethylene oxide, prevents the fruits and vegetables from aging due to excessive ethylene concentration in the storage room, and maintains their freshness for a long time. .

■ Microorganisms such as bacteria, yeast, and filamentous fungi that are attached to fruits and vegetables are sterilized with the ethylene oxide produced in ○, itself, and 03 (f=) to suppress the spoilage of fruits and vegetables caused by microorganisms.

(3) As mentioned in (1) and (2) above, N 2 , 0 3 , and 0 2 are supplied into the storage room 3, and 0 2 decreases due to the respiration of fruits and vegetables, and CO 2 increases. The inside of the storage chamber 3 is filled with atmospheric gases of N2, CO2, 02, and O.

The atmospheric gas in the storage chamber 3 is maintained at a composition as follows.

N2: 90-95% O2: 2-8% Co2: 3-5% 03: 0.0 1-20 ppm Therefore, from the atmospheric gas discharge line 4, mainly N2, C
As a result of ○2 and 02 being exhausted and passed through the gas regulator 18, ① a significant portion of the CO2 is removed by the scrubber 22.

■02 is converted into C○2 by the converter 23.

The gas supplied to the storage room 3 is supplied to the N2 gas supply line 1 and the mixed gas supply line 2 through flow rate adjustment devices 7 and 17.
The composition is adjusted accordingly.

FIG. 2 shows a second embodiment of the present invention, which is based on the basic structure of the first embodiment and slightly modified.

That is, the N2 gas supply line 1 and the ozone gas supply line 12 of the first embodiment are joined to the mixer 14, and the mixer 1
The mixed gas supply line 2 led out from 4 is connected to the storage chamber 3 to supply a mixed gas of N2 and 03 to the storage chamber 3, and the adjusted gas supply line 13 is directly connected without going through the mixer 14. It is connected to the storage chamber 3 and configured to supply N2 and 02 to the storage chamber 3.

《Experiment example》 Atmosphere scum in the storage room is formed by adjusting gas consisting of N2, CO2, 02 and 03 gas. ? J, and the concentration of 03 gas in the entire atmospheric gas is 20 p p
6 green plums in a storage room maintained at 5°C.
As a comparative example, the change in ethylene concentration over time when the sample was stored without using ozone was measured.

Figure 3 shows the results. In the present invention, even after 30 days, the ethylene concentration is maintained at a low level of 0.3 ppm (that is, the excess state of ethylene is eliminated). In the comparative example, after 15 days, the concentration was already 0.5pp.
It can be seen that the amount reached 1.3 ppm after 25 days, which is approximately 4.3 times the value of the present invention.

Therefore, according to this experiment, the effect of ozone on decomposing ethylene is clear, and when the storage device of the present invention is used, it is possible to prevent aging and maintain the freshness of fruits and vegetables such as green plums for a long period of time. I can do it.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a fruit and vegetable storage device showing a first embodiment, FIG. 2 is a diagram corresponding to FIG. 1 showing a second embodiment, and FIG. 3 is a chart showing experimental results.

Claims (1)

[Claims] 1. The gas atmosphere in the storage chamber is made up of a mixed gas of ozone and a conditioning gas containing at least nitrogen, carbon dioxide, and oxygen, and the volume composition ratio of nitrogen and carbon dioxide is set to be higher than that of air, and oxygen is set to be lower. A fruit and vegetable storage device characterized in that it is configured to maintain the freshness of fruits and vegetables by bringing a mixed gas into contact with fruits and vegetables stored in a storage chamber and decomposing ethylene generated from the fruits and vegetables with ozone.