JP2018023313A - Freshness holding method of garden stuff - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding method capable of holding garden stuff safely, while showing an extremely high freshness retention effect, even in a storage chamber such as a container having a volume of 1 mor having a large volume exceeding 10 m, concerning a novel holding method of garden stuff.SOLUTION: When storing and holding garden stuff 2 in a storage chamber 1 such as a container, a packed bed 3 by the garden stuff is formed, and process gas having a hydrogen concentration of 0.1-4.0 vol% is allowed to pass from one side of the storage chamber toward the other side through the packed bed 3 so that a space velocity (SV) becomes 0.1 cm/sec-100 cm/sec.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a novel method for preserving fruits and vegetables. Specifically, the present invention provides a storage method that enables safe storage of fruits and vegetables while exhibiting an extremely high freshness maintaining effect even in a storage room such as a large volume container.

  Conventionally, as a technique for maintaining freshness of fruits and vegetables including fruits and vegetables, a technique for delaying freshness degradation and maturity by holding the fruits and vegetables in an atmosphere of high-concentration carbon dioxide is known (see Patent Document 1). . Further, a technique for delaying freshness degradation and maturation by adsorbing a gas such as ethylene or acetaldehyde that has been confirmed as a hormone gas that promotes maturation is also known (see Patent Document 2). Furthermore, as a method for suppressing maturation by directly acting on the ethylene biosynthesis mechanism in fruits and vegetables, a technique using a drug such as 1-methylcyclopropene (1-MCP) is known (see Patent Document 3).

  Although the above-mentioned method of forming a high-concentration carbon dioxide atmosphere is expected to have a certain effect, if it is applied to the fruits and vegetables accommodated in the large-capacity storage room, an oxygen deficiency is required in the work in the storage room. There is a risk of causing. In addition, the method using adsorption and the method using the drug are effective for packs stored in a small amount, but when storing fruits and vegetables in a storage room such as a large-capacity container, It is difficult to make the treatment agent act.

  On the other hand, a method for bringing a gas containing hydrogen into contact has been proposed for maintaining the freshness of fresh foods such as meat and fish (see Patent Document 4). These freshness-keeping methods utilize the hydrogen reduction action to prevent discoloration of fresh fish, fungi, and oxidative degradation, and are applied to technologies that delay the freshness degradation and ripening of fruits and vegetables. Is not disclosed at all.

Japanese Patent Laid-Open No. 61-216640 WO2015 / 114959 gazette WO95 / 033377 JP 2001-258468 A

Accordingly, an object of the present invention is to safely preserve fruits and vegetables while exhibiting a very high freshness-keeping effect in a storage room such as a large-volume container having a volume exceeding 1 m ³ and further exceeding 10 m ^3. It is to provide a storage method that makes it possible.

  As a result of repeated studies to solve the above problems, the present inventors have found that hydrogen has a maturation suppressing action in the process of ethylene generation in fruits and vegetables, and further includes a dilute concentration below the explosion limit of hydrogen. It has been found that even when used as a gas, the above-described maturation suppressing action can be sufficiently exerted. Further, when the gas containing hydrogen is applied, the effect is effectively exhibited even for fruits and vegetables accommodated in a large-capacity storage room by allowing the gas to pass through the surfaces of fruits and vegetables at a specific speed. The present invention has been found and the present invention has been completed.

  That is, according to the present invention, when the fruits and vegetables are stored and stored in a storage room, a packed layer of the fruits and vegetables is formed, and the space velocity (SV) is directed from one side of the storage chamber to the other through the packed layer. ) Is allowed to pass through a treatment gas having a hydrogen concentration of 0.1 to 4.0% by volume so as to be 0.1 cm / second to 100 cm / second.

In the method of the present invention, the fruits and vegetables may be packaged individually or in a plurality of units by a packaging material. In this case, the packaging material has a hydrogen permeation amount of 1 L / m ^{2 at} 23 ° C. and a humidity of 90% RH. A material of Hr · atm or higher is preferable in order to sufficiently contact the processing gas passing through the packed bed of fruits and vegetables.

  Further, in order to effectively use the hydrogen of the processing gas after passing through the packed bed, the processing gas is preferably circulated. At that time, the hydrogen gas concentration is adjusted to the above range and supplied to the packed bed again. It is preferable to do.

  Further, in such a circulation step, it is preferable to further provide a deethyleneization step in which the circulation gas is brought into contact with the ethylene adsorbent in order to prevent ethylene gas from being generated and accumulated from the fruits and vegetables.

  Furthermore, since the processing gas supplied to the storage room always moves on the surface of the fruits and vegetables, there is a concern that the moisture of the fruits and vegetables will be excessively taken away. In order to prevent such a phenomenon, the processing gas has a relative humidity of 70%. It is preferable to adjust to the above.

  According to the present invention, even fruits and vegetables accommodated in a large-capacity storage room can be continuously supplied with hydrogen and brought into contact with the fruits. High freshness can be maintained over a long period of time.

  The mechanism for maintaining the freshness by hydrogen is presumed to be due to the action of hydrogen on the ACC synthase and / or ACC acid enzyme and ethylene receptor acting in the maturation process of fruits and vegetables to block the maturation process.

  In addition, the hydrogen used in the present invention can exhibit a sufficient effect even at a low concentration of 0.1 to 4.0% by volume below the lower limit value of the air mixing explosion limit, particularly below the lower limit value. Such an effect can be said to be a surprising effect that cannot be assumed from the past application of hydrogen to fresh food. Moreover, by using hydrogen at a concentration below the lower limit of the explosion limit, it is possible not only to ensure safety against explosions, but also by using air as a diluent gas, It is a highly practical technology that can prevent accidents.

  The freshness keeping technology of the present invention is not limited to stationary storage and stockpiling of fruits and vegetables that are used with a fixed storage room, and by combining the storage room with moving means, it enables transportation by land logistics and maritime logistics, It makes it possible to provide fresh fruits and vegetables to overseas consumers.

Schematic showing one embodiment of an apparatus suitable for carrying out the method of the present invention. Schematic showing one embodiment of a packed bed in the implementation of the method of the present invention Schematic of the experimental apparatus used in the examples of the present invention

  The fruits and vegetables targeted by the present invention are not particularly limited as long as they follow the maturation process by the ethylene biosynthetic mechanism incorporated in the fruits and vegetables, but typical examples include cucumber and melon. Cucumbers of the cucumber family, cucumbers of the cucumber family such as bitter gourd, cucurbita genus such as pumpkin and zucchini, cucumber watermelon genus such as watermelon, eggplant genus such as eggplant and potato, eggplant genus such as pepper Apples such as apples, apples, pears, peaches, peaches, roses, peaches, roses, Dutch strawberry, raspberries, roses Genus, rosaceae such as cherries and apricots, genus ceraceae such as figs, citrus genus such as citrus, lemon, grapefruit and lime, blueberries, etc. Azalea, banana, etc., papaya, papaya, papaya, mango, etc. Fruits such as cypress, Avocado, etc. Brassicaceae genus Brassica genus such as cauliflower and Romanesco, Brassicaceae radish genus such as radish and radish, Seriaceae carrot genus such as carrot, Seriaceae cumin genus such as cumin, Seriaceae such as coriander genus such as coriander, Amaryllidaceae genus such as leek and sea urchin, nin Liliaceae such as cucumber, Lamiaceae such as oregano Examples include vegetables such as Chrysanthemum genus Chrysanthemum, such as chalk, and Dogwood genus Mesembrianthema, such as ice plant.

In the present invention, the storage room for storing and storing fruits and vegetables includes containers such as containers, rooms in buildings, etc. having a large capacity space of 1 m ³ or more, particularly 10 m ³ or more. . In the case of a container such as a container, the upper limit of the volume is about 300 m ³ because of the possibility of transportation. In addition, the storage chamber is generally a cube or a rectangular parallelepiped, but can also be a cylinder, a polygonal column, or a sphere.

  FIG. 1 shows an embodiment of an apparatus including a storage room suitable for carrying out the method of the present invention. In FIG. 1, the storage chamber 1 is connected to a supply line for processing gas containing hydrogen at the lower part and to a discharge line for processing gas at the upper part. 1 is a mode in which the processing gas is circulated from the lower side to the upper side of the storage chamber. In the present invention, the processing gas is directed from one surface of the storage chamber to the other surface facing the other. For example, a mode in which the processing gas is circulated from the side surface of the processing chamber toward the other side surface facing the processing chamber is also possible.

  Returning to the description of FIG. 1, a breathable support 4 that supports a fruit and vegetable layer 3 to be described later is provided on the processing gas inlet side of the storage chamber 1. Such a breathable support 4 needs to have breathability in order to pass the processing gas and supply it to the packed bed 3, and specifically, a net, a lattice having a strength capable of supporting the fruit and vegetable layer, Or it is preferable to comprise by a perforated plate etc.

  Further, in order to supply the processing gas uniformly over the entire surface of the filling layer 3, it is preferable to provide a rectifying plate 5 for adjusting the opening degree and attaching resistance. Thus, the processing gas supplied to the storage chamber 1 passes through the packed bed 3 and is discharged from the storage chamber 1.

In the present invention, it is important for the fruits and vegetables accommodated in the storage chamber to form the packed bed 3 in the flow path of the processing gas containing hydrogen described later in the storage chamber 1. That is, by forming a packed bed of fruits and vegetables, the processing gas containing hydrogen can pass uniformly between the fruits and vegetables accommodated in the storage chamber, and the fruits and vegetables in the storage chamber can be subjected to the above-described action of hydrogen. For this reason, the packed bed needs to be configured so that the processing gas passes evenly through the fruits and vegetables. In particular,
(1) A mode in which a packed bed is formed only by stacking fruits and vegetables,
(2) As shown in FIG. 1, a mode in which a plurality of fruits and vegetables are put into a sub-container 10 having an opening through which a processing gas can flow, and a packed bed is formed by arranging the fruits and vegetables,
(3) As shown in FIG. 2, the aspect etc. which mount fruit and vegetables on shelf members 11, such as a net-like, and provide one step | paragraph or multiple steps | paragraphs and comprise a packed bed, etc. are mentioned.

  As described above, the sub-container used in the aspect (2) appropriately adopts a structure that allows ventilation in the flow direction of the processing gas. For example, in FIG. 1, a sub-container 10 is provided with a net-like or porous bottom plate at the bottom and a lid plate having an opening at the top.

  By configuring the packed bed in this way, as will be described later, a flow at a constant speed or higher is always formed in the packed bed, so that it is possible to stably contact hydrogen with fruits and vegetables. .

Moreover, when forming the packed bed of fruits and vegetables, the fruits and vegetables may be packaged individually or in a plurality of units by a packaging material. In this case, the packaging material has a hydrogen permeation amount at 23 ° C. and a humidity of 90% RH. Is preferably 1 L / m ² · Hr · atm or more in order to sufficiently contact the processing gas passing through the packed bed of fruits and vegetables. Specific examples of the packaging film include a resin film such as a polypropylene film having holes having a diameter of 1 to 10 mm, a nonwoven fabric made of a resin such as polypropylene, a net, and a sheet.

  Here, the amount of hydrogen permeated is determined by installing the packaging material in a sealed container and partitioning the container with the packaging material, replacing the gas in one space partitioned by the packaging material with hydrogen gas, Measurement is performed by measuring.

  In the present invention, the processing gas that passes through the packed bed is a gas having a hydrogen concentration of 0.1 to 4.0% by volume, preferably 0.2 to 3.0% by volume. It is a surprising fact that the high freshness retention effect of fruits and vegetables can be obtained only by the presence of a low concentration of hydrogen in the processing gas, and it works synergistically with the effect by specifying the space velocity of the processing gas described later. It is presumed that the effect is obtained.

  In the processing gas, a diluent gas, that is, a gas other than hydrogen is not particularly limited as long as it does not adversely affect the fruits and vegetables, but considering the safety of workers in the storage room, Air is most preferred.

  In the present invention, the space velocity (SV) is 0.1 cm / second to 100 cm / second, preferably 1 cm / second to 50 cm / second from one side of the storage room to the other through the packed bed of fruits and vegetables. Thus, it is important to allow the processing gas to pass through. That is, when the space velocity is slower than the above range, sufficient hydrogen cannot be brought into contact with the surface of fruits and vegetables, and the freshness maintaining effect is lowered. Further, even if the space velocity is faster than the above range, the effect is not limited, and the equipment cost is high and it is not economical.

  Here, the space velocity (SV) of the processing gas is indicated by a value obtained by dividing the amount of processing gas flowing through the storage chamber by the cross-sectional area perpendicular to the processing gas flow direction in the storage chamber. For example, in the storage chamber shown in FIG. 1, the flow rate of the processing gas measured by a flow meter installed in the upper processing gas discharge line is divided by the cross-sectional area of the storage chamber 1.

  The space velocity is preferably within the above range by adjusting the amount of processing gas containing hydrogen supplied from below.

  In the present invention, in order to effectively use the hydrogen of the processing gas after passing through the packed bed, the processing gas is preferably circulated. At that time, the hydrogen gas concentration is adjusted to the above range, and the packed bed is again used. It is preferable to supply to. FIG. 1 shows a typical mode for circulating the processing gas. That is, the exhaust gas discharged from the storage chamber 1 detects the hydrogen concentration by the hydrogen concentration controller 7 and operates the control valve by comparing the set value with the detected value by the hydrogen concentration controller (not shown). The hydrogen supply amount from the hydrogen tank 6 is adjusted.

  Further, in the process gas circulation step, when ethylene gas is generated from the fruits and vegetables, it is preferable to further provide a deethyleneization step for bringing the circulation gas into contact with the ethylene adsorbent in order to prevent the accumulation. The ethylene removal step can be carried out by attaching an adsorption tower filled with an ethylene adsorbent to at least one location of the circulation line. As the ethylene adsorbent, known adsorbents such as activated carbon, silica gel, bamboo charcoal, zeolite, natural minerals such as Oyaishi are used without particular limitation. In addition, the process of decomposing ethylene is also used without limitation.

  In the present invention, since the processing gas supplied to the storage chamber 1 continuously moves on the surface of the fruits and vegetables, there is a concern of excessively depriving the fruits and vegetables of moisture. In order to prevent such a phenomenon, it is preferable to adjust the relative humidity of the processing gas to 70% or more, preferably 90% or more. A method for adjusting the relative humidity of the processing gas to the above range is not particularly limited, but a method of submerging the processing gas in water, a method of supplying water vapor to the circulation line, a method of supplying water vapor directly to the storage room, etc. Is mentioned.

  In order to describe the present invention more specifically, examples are shown, but the present invention is not limited to these bags.

Examples 1-6, Comparative Examples 1-8
Using the apparatus shown in FIG. 3, the effect of the present invention was confirmed with respect to the composition and space velocity of the processing gas passing through the packed bed of fruits and vegetables. That is, a cubic glass container with a capacity of 64 liters is used as the storage chamber 1, a stainless steel net shelf 11 is attached to the middle of the space, and the fruits and vegetables shown in Table 1 are stored and filled in the net shelf 11 as a specimen. Layer 3 was formed. The processing gas whose gas composition was adjusted by the gas composition adjusting device 13 so as to have the gas composition shown in Table 1 was supplied to the storage chamber 1 so as to have the space velocity shown in Table 1. Although not shown in FIG. 3, showering was performed on the gas in the circulation system so that the humidity of the processing gas circulated and supplied to the storage chamber 1 was 90%.

  Under the above conditions, each specimen was stored for the period shown in Table 1, and then the time-dependent change and state of the specimen were observed and the gas composition was measured. The space velocity (SV) was calculated using the flow rate measured by the flow meter 12 installed in the discharge line. Further, the hydrogen gas concentration and the ethylene gas concentration in the container were measured by gas chromatography.

  The above test was performed under conditions of a temperature of 20 ° C., atmospheric pressure, and indoors (with a fluorescent lamp 400 LX). In Comparative Example 8, the temperature was set to 10 ° C., and the others were tested under the conditions shown in the table.

Example 7
With respect to the embodiment shown in FIG. That is, a cubic stainless steel container having an inner volume of 1 m ³ is used as the processing chamber 1, and a corrugated cardboard box having an outer size, a width of about 50 cm, a length of about 100 cm, and a height of about 60 cm is placed on the support 4. Placed side by side.

  The bottom and top surfaces of the box were opened, and a wire mesh was provided at the bottom opening.

  The corrugated pole box is filled with 30 apples as specimens to form a packed bed 3 of fruits and vegetables. The gas composition adjusting device 13 shown in detail in FIG. The processing gas adjusted to the gas composition was circulated in the processing chamber so that the space velocity was 5 cm / second. Further, although the circulating gas is not shown, the humidity was maintained at 90% or more by showering the circulating gas.

  Samples were stored for 30 days under conditions of room temperature and 20 ° C. under atmospheric pressure. As a result, no abnormalities such as generation of mold, softening of flesh, and decay were observed in all samples.

1: Storage room 2: Fruits and vegetables 3: Fruits and vegetables layer 4: Breathable support body 5: Rectifying plate 6: Hydrogen tank 7: Hydrogen concentration controller 8: Adjustment valve 9: Compressor 10: Subdividing container 11: Shelf member 12: Flow rate Total 13: Gas composition adjusting device

Claims (5)

  When the fruits and vegetables are stored and stored in a storage room, a packed bed of the fruits and vegetables is formed, and the space velocity is from 0.1 cm / second to 100 cm / second from one side of the storage room to the other through the packed bed. The method for preserving fruits and vegetables is characterized by allowing a treatment gas having a hydrogen concentration of 0.1 to 4.0% by volume to pass through. The method for preserving fruits and vegetables according to claim 1, wherein the fruits and vegetables are packaged by a packaging material having a hydrogen permeation amount at 23 ° C and a humidity of 90% RH of 1 L / m ² · Hr · atm or more.   The method for preserving fruits and vegetables according to claim 1 or 2, further comprising a circulation step of adjusting the hydrogen concentration of the processing gas after passing through the packed bed to the range and supplying the hydrogen to the packed bed again.   The method for preserving fruits and vegetables according to claim 3, further comprising a de-ethylene removal step of bringing the circulating gas into contact with the ethylene adsorbent in the circulation step.   The preservation method of fruits and vegetables as described in any one of Claims 1-4 including the humidity control process which adjusts the relative humidity of the process gas supplied to the said storage chamber to 70% or more.

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