JPS60118144A - Freshness preservation of vegetables and fruits or flowers and trees - Google Patents

Abstract

PURPOSE:To improve further freshness preservation of vegetables and fruits or flowers and trees, by circulating air in a storehouse preserving vegetables and fruits or flowers and trees in such a way that the air is brought into contact with a specific carbonaceous molecular sieve on which bromine is adsorbed. CONSTITUTION:Air in a storehouse preserving vegetables and fruits or flowers and trees is circulated in such a way the air is brought into contact with a carbonaceous molecular sieve having 4-6Angstrom micro pores on which bromine is adsorbed so that freshness of vegetables and fruits or flowers and trees is kept. The air in the storehouse is preferably circulated under conditions where circulation times (a value obtained by dividing an amount of air to be brought into contact with carbonaceous molecular sieve by volume in storehouse par hour) is 1-50 times/hr, and space velocity per volume of carbonaceous molecular sieve is 100-350,000/hr.

Description

[Detailed description of the invention] The present invention relates to a method for preserving the freshness of fruits, vegetables, or flowers and trees.

Conventionally, one method of preserving freshness when storing fruits and vegetables is to place carbonaceous molecular sieves that have activated carbon or bromine adsorbed in the storage containers of fruits and vegetables, and use the substances released by the plants themselves to promote ripening. By removing some ethylene,
There are known methods for preserving the freshness of fruits and vegetables. However, with the conventional method of simply leaving an ethylene adsorbent in place, if there are a large amount of fruits and vegetables, the adsorbent's ability to remove ethylene may be insufficient. When stored, the solubility retention effect is not always satisfactory. Therefore, even if a large amount of ethylene removing agent is used, as long as the above-mentioned known method is used to maintain the freshness of fruits and vegetables, it will not be possible to sufficiently suppress overripeness of fruits and vegetables, and the concentration of radionuclides in the refrigerator will be lower than the S ratio. The aroma and taste may change during storage.

The inventors of the present invention have made various studies in view of the above drawbacks. i! We have found that by circulating the air in the storage room into contact with carbonaceous molecular sieves that have adsorbed bromine, the freshness of fruits and vegetables can be kept much better compared to conventional methods.

According to the present invention, the ethylene emitted from the plant body is removed extremely efficiently, so the effect of suppressing ripening is good, and the oxygen and carbon dioxide gases in the refrigerator are kept at relatively natural concentrations for a long period of time. It can prevent deterioration of the taste and aroma of fruits and vegetables.

The present invention has been made based on the above findings.

That is, the present invention is characterized in that the air in a storage containing fruits, vegetables, or flowers and trees is circulated so as to come into contact with a carbonaceous molecular sieve having 4 to 6X micropores that adsorbs bromine. This is a method of preserving freshness.

The brominated molecular sieve charcoal used in the present invention is obtained by adsorbing bromine onto a carbonaceous molecular sieve having 4 to 6× micropores.

The carbonaceous molecular sieve has an elemental composition of 9096 or more carbon, 3% or less oxygen, and 1% or less hydrogen, and a surface area of 400 to 9
00 m”/IF, more than 80% of the total micropore volume is 4~
It consists of micropores with a pore diameter of 6 angstroms. This special carbonaceous molecular sieve can be produced by, for example, the method described in Japanese Patent Publication No. 37036/1983, in which the raw material for making phenolic resin or furan tea tree (finger) is adsorbed on a carbon adsorbent by polymerization and/or condensation. After condensation, it can be obtained by heating at about 400 to 1000°C.The carbon adsorbent can be any porous carbon material that has adsorption performance. Usually, active legs or those with similar performance are preferably used.In other words, carbon materials with a large adsorption and retention capacity for the adsorbed raw material, and micropores, especially those with developed pores with a pore diameter of 2OA or less, are preferably used. A granular material having a pore distribution, excellent hardness, and toughness is desirable.The raw materials to be adsorbed to the carbon adsorbent include phenol, cresol, which has been polymerized and/or condensed to form a phenol-based fat, Pheno-/l' necks such as xylene-p and aldehydes such as formaldehyde, acetaldehyde, benzaldehyde, and furfural, or polymerization and/or condensation to produce furan-based resins) fuller, either alone or as a mixture. The amount of the raw material to be used is preferably about 0.1 to 1.0 g per 1 cc of pore volume with a pore diameter of 300" is about 0.3
It is preferable to select the amount within the range of ~0.7 g, and for this purpose, the amount of pores per 1 ffl pore volume ICC of 300× or less pores of the raw material carbon adsorbent is usually about 0.1 to 2. Oq
Preferably po, it is good to use 3 to 1.5 g of raw material. These raw materials can also be used after being appropriately mixed with a carbon source such as lignin and pit sugar phase, and a carbon fixing agent such as an aromatic nitro compound. In order to polymerize and/or condense the above-mentioned raw materials in an active manner, it is preferable to use a catalyst, and such catalysts include commonly used catalysts, such as caustic soda, caustic potash, hydroxide, etc. for the raw materials for making phenolic resins. Alkali catalysts such as barium and ammonia, or acid catalysts such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid, oxalic acid, and succinic acid; hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid,
Examples include acids and/or acidic salts such as oxalic acid, succinic acid, boric acid, zinc chloride, and magnesium chloride.
Alkaline catalysts are preferred for pheno-μ tea resins.

It is preferable that the amount of the catalyst to be used is selected based on the resin-forming raw material in the following order.

Pheno-p tea resin alkaline catalyst: 1-10% Acid catalyst: 2-30% Furan-based resin composition: 10% or less
A solution diluted with an appropriate solvent such as water, methanol, benzene, or creosote oil may be prepared, and the solution may be sprayed or immersed in the carbon adsorbent to adsorb and support the raw material. The substance may be adsorbed and supported on a carbon adsorbent in a gas phase.

When using a catalyst in combination, first absorb the catalyst into the staghorn material, and
A method of supporting and then adsorbing and supporting the raw material,
There are two methods: first, the raw material is adsorbed and supported, and then the catalyst is adsorbed and supported, or they are both adsorbed and supported at the same time, but the preferred method is to first support the catalyst and then support the raw material. . Also, the operation is 2
It can also be divided into more than one time. These adsorbed raw materials and catalysts can be adsorbed and supported in any combination and order. In the method of the present invention, the polymerization and/or condensation of the raw material progresses due to the heat of adsorption generated when the raw material is adsorbed by the cumulative adsorption agent.
Furthermore, if necessary, the polymerization and/or condensation reaction can be accelerated by heating to room temperature to 200°C. During this heating, the solvent and some unreacted components are desorbed and volatilized. The carbon adsorbent thus treated is then subjected to a swelling treatment. For the legalization treatment, processing means used in the ashing step during normal activated carbon production are used. That is, the swelling treatment can be performed by pre-oxidizing the material in advance and then carbonizing it, or by directly carbonizing it. Pre-oxidation may be carried out at a low temperature in an atmosphere containing VA. As a legalization process, 4
12. At a temperature of 00-1000℃. 'H2, He, G
For example, heating may be carried out in an inert gas stream such as Go3.802 or in a vacuum. It doesn't matter if the kernels contain a small amount of oxygen. The temperature increase rate is usually 50°C/hr to 400°C to slow down the decomposition rate of the resin.
About ti/hr is desirable. The axial pore diameter of the carbonaceous molecular sieve obtained in this way is mostly in the range of 4 to 6 angstroms, and the relationship between the pore diameter and axial pore capacity is as follows.
For example, it is indicated by M2O-A in FIG. Note that ordinary activated carbon has large pore diameters and is distributed over a wide range, as shown by activated carbon-B in FIG. 1, for example.

When this property is used to maintain the freshness of fruits and vegetables, ethylene, aldehydes, alcohols, ketones, and esthetics are released from the fruits and vegetables. It selectively adsorbs only low-molecular substances such as V-cheeks, ethylene, aμdehyde, and alcohol, and contains ketones, which are aromatic components unique to fruits and vegetables.
Since it does not adsorb Group I/etc., it exhibits an extremely excellent performance of maintaining the aroma characteristic of fruits and vegetables.

The carbonaceous molecular sieve may be used for deep bed adsorption as it is, but prior to this, it may be loaded with a small amount of phosphoric acid, boric acid, or their salts. It is possible to further suppress deterioration over time of the ability of chemical molecular sieve charcoal to retain the freshness of fruits and vegetables. These compounds can be supported by scattering and absorbing an aqueous solution of an appropriate concentration onto a carbonaceous molecular sieve, or by immersing a carbonaceous molecular sieve in an aqueous solution and supporting the compound by liquid phase adsorption.

The amount of the compound of Jin et al. supported is usually 0.02 to 2% by weight, preferably 0.05 to IMtffi%.

The amount of bromine adsorbed on the carbonaceous molecular sieve is 2 to 30% by weight,
Preferably it is 5 to zo'Ai, % by weight.

As a method for adsorbing bromine onto a carbonaceous molecular sieve, there are conventional adsorption methods, such as (1) a gas phase adsorption method in which a carrier gas containing bromine gas is brought into contact with a carbonaceous molecular sieve, (2)
The liquid phase adsorption method involves immersing charcoal and a molecular sieve in bromine water, or the method of directly spraying liquid bromine onto a carbonaceous molecular sieve for adsorption. Most preferred.

In the above gas phase adsorption method, the carrier gas is
Examples include air, nitrogen, and carbon dioxide gas. The mixing ratio of bromine gas and carrier gas is usually such that the concentration of bromine gas is 30% by volume or less, but preferably O, OS to 2% by volume. The contact temperature is 15.0°C or less, preferably 8°C.
The temperature is below 0°C. Note that heat of adsorption is generated during adsorption, so it is best to consider the melting method, gas, and adsorption container temperatures so that the temperature does not exceed 150°C. An example is a continuous gas phase adsorption method in which a bromine-containing gas is circulated and brought into contact with a fluidized bed, moving bed, spouted bed, etc.The bromine-adsorbed molecular sieves obtained by adsorbing bromine in this way are then exposed to bromine. It is preferable that a carrier gas containing no bromine be passed through the bromine at a temperature of less than 1000 ml to desorb unadsorbed bromine.

In the liquid phase adsorption method, bromine water with a bromine concentration of about 2 to 396% is added at a temperature of 50°C or lower, preferably 30°C or lower.
The carbonaceous molecular sieve that has adsorbed bromine is soaked for about 10 hours, and after the adsorption is completed, the carbonaceous molecular sieve that has adsorbed bromine is drained by a method such as passing through and dried to obtain the molecular sieve charcoal that has adsorbed bromine (used in the present invention).
(hereinafter referred to as brominated molecular sieve charcoal).

In addition, in the method of spraying liquid bromine onto a carbonaceous molecular sieve, liquid bromine is directly sprayed onto the ash layered molecular sieve while stirring.
A brominated molecular sieve charcoal can be obtained by drying if necessary. The temperature when spraying liquid bromine is preferably 5 gb or less.

The brominated molecular sieve charcoal used in the present invention is preferably used in the form of granules such as spherical or cylindrical molded pellets or asymmetrically crushed pellets, and the size thereof is 2 to 10 mm in diameter, preferably 3 to 6 mm in diameter. Things are appropriate. These are usually filled with honeycomb cores, etc., or non-woven fabrics such as urethane foam, synthetic fibers, natural fibers, or gold. Although it is generally used in the form of a filter, it may be used in any other form. Among these, it is preferable to use one filled in a honeycomb core while adjusting the pressure loss during ventilation.

The amount of brominated molecular sieve charcoal used varies depending on the type of fruits and vegetables, storage period, etc., but it is usually 0.1 kl per 1 m3 of storage volume.
) to 5 kg, preferably 02 to 1 kg.

In the present invention, the air in the storage room containing fruits, vegetables, flowers, and trees is circulated so as to come into contact with the brominated molecular sieve charcoal. The air volume divided by the storage internal volume) is 1 to 50 times/hr, and the space velocity per volume of brominated molecules ra is 100 hr" to 350.0 OO.
This is done under conditions such that hr'.

The present invention can be applied to all fruits, vegetables, and flowering trees, but is particularly applicable to apples, melons, pears, and moles.
．． Fruits such as bananas, grapes, cherries, lemons, plums, nectarines, and sudachi, tomatoes, strawberries, broccoli, and cauliflower.

Vegetables such as asparagus, bamboo shoots, shiitake mushrooms, spinach, chives, lettuce, cabbage, and orchids.

It can be preferably applied to flowering trees such as lilies, carnations, puffs, and chrysanthemums.

The present invention can be implemented using an apparatus such as that shown in FIGS. 2 and 3, for example. In the apparatus shown in FIG. 2, fruits and vegetables (2) are stored in a storage (2), and a gas circulation fan causes the air in the storage to pass through an ethylene removal filter using brominated molecular sieve charcoal.

In addition, in the device shown in Fig. 3, the air in the storage chamber ■ is stored in the storage I
A gas circulation fan installed outside the storage area leads to an ethylene removal filter■ and a gas circulation path■
through which it is led back into the storage room. In this way, the ethylene removal filter ■ and the gas circulation fan ■ are inside the storage.
Although it may be installed anywhere outside the storage, it is preferable to install the gas circulation fan outside the storage because it generates heat from the motor.

According to the present invention, it is possible to very efficiently remove the ethylene in the storage room that volatilizes from fruits and vegetables or flowers and trees, and the freshness of the fruits and vegetables or flowers and trees can be maintained for a long period of time. It is also possible to maintain the characteristic fragrance of fruits, vegetables, or flowers and trees upon leaving the warehouse.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example 1 Internal volume 0-11n3*Gas circulation air volume 0.033 m3/
mtn, ([4 times 19.8 FBI/Hr, )
(Dm Z Prepare two units of the equipment shown in Figure D, and each unit has 4 to 4
6-mesh cylindrical brominated molecular sieve charcoal [Kyokuryaku Kogyo Co., Ltd.
Molcibon 5A made by Kiki (analysis value 095%, 02%,!
10.8%, ash 1.5%9 surface area 600 M”/su,
Volume of 4 to 6A pore diameter ¥93% of total micropore volume)
brominated with 10% bromine) 50g
A honeycomb core-type ethylene removal filter filled with
, 1,971,7973 pieces (1,77#) were put in and sealed. The number of cycles at this time is 19.8 +! ! ]/hr, the space velocity is 27-000 hr-1%. As a control, a honeycomb core type filter was installed in another unit without filling with brominated molecular sieve charcoal, and similarly 2 amsu melons (2,44#) and 3 7' rinse melons were installed. (1,78#), seal it, operate the fan at a room temperature of around 20℃ to circulate the gas in the device, sample the gas in the device at a predetermined time every day, and check the concentration of ethylene, carbon dioxide, and oxygen. The samples were stored for 6 days while being measured, and the results shown in Table 1 were obtained.

In the control plot, the pulp was more softened and the taste was dull compared to the plot using brominated molecule hnlj2.

Example 2 Using the equipment used in Example 1, 19 pears (variety Kosui) (approximately 4 out of 9) were stored for 4 days under the same circulation conditions as in Example 1, with the air inside the refrigerator circulated. , the results shown in Table 2 were obtained.

Example 3 Internal volume 0.26f#”*Gas circulation air volume 0.083,,
'ywin' apparatus 2J boxes (hereinafter referred to as A and B boxes) shown in Figs. Install a removal filter and pear (variety, Kosui) 1
Three pieces (approximately 34#) were placed in the container and the container was sealed. Box A operates a fan to circulate the gas inside the box into contact with the ethylene removal filter (number of circulations: 19°2 times/hr, space velocity: 9.
700 hr), but the three boxes were stored in a stationary state for 9 days without operating the fan, sampling the gas inside the box at a predetermined time every day and measuring the concentration of ethylene, carbon dioxide, and carbon dioxide. , the results shown in Table 3 were obtained.

Table 3 a, Gas analysis results, Analysis results of fruits after storage (1 week after shipping) Example 4 Three devices similar to those used in Example 3 (hereinafter C, D
Boxes C and D were each filled with 350 g of the brominated molecular sieve charcoal used in Example 1, t and i were filled with honeycomb core type ethylene removal filters, and box E was filled with brominated molecular sieve charcoal. Instead, only honeycomb core type filters were installed, each with 117,225 connectors [approximately 75 to '7. 6 cases of 9 varieties (Hideho) from Takayama Village, Nagano Prefecture (2Llo pieces/5kti') and 9 cases of L (25 pieces 15 & 9) were placed and sealed.

At room temperature (21 to 27°C), the fan was operated only for CγI to circulate the gas inside the silk under the same circulation conditions as in Example 3, and boxes D and E were stored in a stationary state for 6 days. The gas in each box was sampled every day at a predetermined time to determine whether ethylene, enemy gas, ri! The two-prime individuality was measured. The results are shown in Table 4.

Six days after the start of the experiment, 15 fM+ of each sample was taken, and the hardness, acidity, sugar content, and incidence of straw rot were measured. The results are shown in Table 5.

Table 4 Gas analysis results Table 5 Storage days = 6 days

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a typical example of the pore size distribution of a carbonaceous molecular sieve and ordinary activated carbon, which are the raw materials for the brominated molecule S. FIG. 2, FIG. 3, and FIG. 4 are schematic diagrams of the freshness keeping device. Figure 2 is a side view of the ethylene removal filter and gas circulation fan installed inside the container.
FIG. 3 is a plan view of these devices installed outside the container, and FIG. 4 is a side view of the apparatus shown in FIG. 3. FIG. 5 is a perspective view of the ethylene removal filter. The details of ■ to ■ in the figure are as follows. ■ Styro fi/Tree PJ@ container ■ Gas circulation fan ■ Ethylene removal filter ■ Gas circulation path ■ Honeycomb core - ■ Brominated molecular sieve charcoal ■ Fruits and vegetables for experiments Should be 1, 2, or 3

Claims (1)

[Claims] 1) A storage containing fruits, vegetables, or flowers and trees.
A method for preserving the freshness of fruits, vegetables, or flowers and trees, characterized by circulating the fruits and vegetables or flowers and trees in contact with a carbonaceous molecular sieve having 4 to 6X micropores on which bromine is adsorbed. 2) The number of times the air in the storage is circulated (per hour, the amount of air that comes into contact with the carbonaceous molecular sieve divided by the internal volume of the stored iRN)
1 to 50 times/hr and the space velocity per volume of the carbonaceous molecular sieve is 100 hr-" to 350.000 hr". How to keep it fresh.