JPH04210552A - Method for keeping freshness of green vegetable - Google Patents

Abstract

PURPOSE:To effectively keep the freshness of green vegetables at a low cost by sealing green vegetables in a microporous film bag optionally together with a water bag, an ethylene-absorbing agent, etc. CONSTITUTION:Fresh green vegetable is sealed and preserved in a bag made of a microporous film. As an alternative method, a fresh green vegetable is sealed in the above bag together with a water-bag produced by filling a small bag of the microporous film with water or a hydrated water-absorbing substance. If necessary, a bag containing an ethylene-adsorbent is placed together with the water-bag to keep the freshness of the fresh green vegetable for a long period.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preserving the freshness of fruits and vegetables, and more specifically,
This invention relates to a method for preserving the freshness of fruits and vegetables by storing fruits and vegetables in a bag using a microporous film alone or in a bag together with a water bag, an ethylene adsorbent, etc.

[Conventional technology]

It is widely known that fruits and vegetables, so-called fruits and vegetables, generate ethylene gas during storage, and that the freshness of fruits and vegetables decreases due to the influence of ethylene gas.

As a method for preserving the freshness of fruits and vegetables, for example, a freshness preserving agent for fruits and vegetables that utilizes the ethylene gas adsorption ability of bromine-treated activated carbon is known (Japanese Patent Publication No. 55-50451).
. In addition, a small amount of metal oxide is mixed with the crushed powder of microporous materials such as zeolite and Oya stone, and the mixture is mixed, granulated, and sintered into pellets, which are then treated with oxygen by electromagnetic waves or ozone. It has been proposed to delay the ripening of fruits and prevent spoilage and to maintain the freshness of vegetables by adsorbing ethylene gas and oxidizing the oxidation catalyst material using an oxidation catalyst material (Japanese Unexamined Patent Publication No. 61-93835). In addition, recently, vegetables and other items have been placed in bags made by dispersing and containing fine particles of crushed Oya stone in the film layer and surface of low-density polyethylene film. It has also been proposed to maintain freshness (Japanese Patent Application Laid-open No. 1-132334).

[Problem to be solved by the invention]

However, the freshness-keeping effect of bromine-treated activated carbon is relatively small, and although the above-mentioned oxidation catalyst material has a high freshness-keeping effect, it is not practical due to high raw material and manufacturing costs. Furthermore, bags made by dispersing and containing fine particles crushed by Oyaishi in a polyethylene film are relatively low in cost and have a certain degree of freshness-keeping effect, but they are not completely satisfactory.

In this way, a method for maintaining freshness that is both cost and effective is not yet known.

[Means and effects for solving the problems] The present inventors have solved these problems, and the cost is low,
In addition, as a result of extensive research to find a highly effective method for preserving freshness, we have found that by storing fresh fruits and vegetables in a bag made of microporous film alone, or by storing fresh fruits and vegetables in this bag together with a water bag and an ethylene adsorbent. The present invention was completed by discovering that an excellent freshness retaining effect can be obtained.

That is, the present invention provides (]) a method for preserving the freshness of fruits and vegetables, characterized by storing, sealing, and preserving fresh fruits and vegetables inside a bag using a microporous film; (2) a bag using a microporous film. A water bag that contains water or a water-absorbing substance soaked in water in another pouch made of microporous film;
A method for preserving the freshness of fruits and vegetables, characterized by simultaneously storing, sealing, and preserving fresh fruits and vegetables; The freshness of fruits and vegetables is characterized by simultaneously storing, sealing, and preserving fresh fruits and vegetables, a water bag containing a water-absorbing substance soaked in water, a drug bag filled with an ethylene adsorbent, and fresh fruits and vegetables. This is a holding method.

In the present invention, the microporous film used for the bag has a large number of breathable micropores, and the equivalent diameter of the pores determined by the maximum bubble pressure method of air-methanol system is usually 20μ.
The thickness is preferably about 0.001 to 10 μm, more preferably about 0.01 to 5 μm.

Microporous films can be made of fibers such as nylon, polyethylene, polypropylene, polyester, etc. stacked randomly and bonded together by heating and pressure, or synthetic resins such as polyethylene, polypropylene, polyvinyl chloride, or nylon with calcium carbonate and silicon dioxide. , in which an inorganic material such as aluminum oxide is dispersed, extrusion molded into a sheet shape, and then a large number of air permeable micropores are created by -axial or biaxial stretching.

Typical examples of such microporous films include Tyvek (Dupont, USA) and Boretex (Bohr, USA).
, Juraguard (Celanese, USA), Cellboa (Tanezu Chemical Industry ■), NF Receipt Tokuyama Soda ■), Borum (
Nitto Denko ■ etc., all of which are commercially available and can be selected as appropriate.

These microporous films can be used alone, but for the purpose of reinforcing the bag and adjusting air permeability in advance, the microporous film may be laminated with a perforated film or nonwoven fabric, or the two may be partially laminated. A laminated sheet may be used as the ventilation surface, such as by adhering to the material. An example of a sheet made by laminating a microporous film with a nonwoven fabric is Breathlon (Nitto Denko ■).

The air permeability of these microporous films or laminated sheets is usually 100~100 in terms of water vapor permeability (JISZ 020g).
2000g/m”-day, preferably 2oO
~8o.

g/m”・day.

The fruit and vegetable storage bag may be made of Kosera's microporous film or the laminated sheet described above, or may be made of a combination of other sheet materials; The former type is usually used for simplicity and uniformity of ventilation.

In the present invention, a water bag incorporating water or a water-absorbing substance containing water is used, if desired. The amount of water in the water bag may be sufficient to compensate for the moisture released from fruits and vegetables during storage, and is adjusted as appropriate depending on the type and amount of fruits and vegetables to be stored.

For the water bag, the above-mentioned microporous film or laminated sheet is used because it does not allow water to pass through, but allows only water vapor to pass through. Further, in order to adjust the evaporation rate of water, water may be used in a state where it is impregnated with a water-absorbing substance. Examples of the water-absorbing material include paper, woven fabric, corrosive cloth, and polymeric absorbent materials that have a large amount of water absorption, and among these, polymeric water-absorbing agents or paper and cloth mixed with polymeric water-absorbing agents are preferred. Examples of commercially available polymeric water absorbing agents include KI Gel (Kuraray ■), Sunwet (Sanyo Kasei ■), Sumikagel (Sumitomo Chemical ■), and Aqualic (Nippon Shokubai Chemical ■). You can choose the one that is suitable for you.

To maintain the freshness of fruits and vegetables during normal storage periods, storing fruits and vegetables alone in bags made of microporous film or storing fruits and vegetables together with water bags and sealing them will provide sufficient freshness-keeping effects, but the storage period will be limited. If the storage is to last for a long period of time, it is preferable to store an ethylene adsorbent at the same time. In this case as well, since ethylene gas is relatively well permeated to the outside of the bag through the fine pores of the bag containing fruits and vegetables, a relatively small amount of ethylene adsorbent is required.

As an ethylene adsorbent, a small amount of metal oxide is mixed with the above-mentioned bromine-treated activated carbon, pulverized powder of microporous materials such as zeolite and Oya stone, and the mixture is kneaded, granulated, and sintered into pellets, which are then exposed to oxygen using electromagnetic waves or ozone. In addition to oxidation catalyst materials made of treated sintered material or powder thereof, activated carbon in the form of powder, lumps, or pellets to which 0.05 to 3% palladium is added can be used. These ethylene adsorbents are usually filled into pouches with a large number of micropores and used as drug bags.

In the present invention, the storage conditions for the bag containing fruits and vegetables are as follows:
- It is desirable to keep the temperature low for boat fishing, and for long-term storage, it is preferable to keep the temperature at 1 to 5°C and the relative humidity at about 50 to 60%.

〔Effect of the invention〕

The present invention has the following excellent practical effects.

■Because microporous film is used for the bag material, ethylene,
Water vapor, oxygen, carbon dioxide gas, nitrogen gas, etc. naturally permeate to the outside of the bag, so the freshness of fruits and vegetables can be maintained for a long period of time.

■The amount of gas permeation of microporous film can be easily controlled by adjusting the degree of stretching and overlapping with perforated film, so bags suitable for various types of fruits and vegetables can be obtained.

■Microporous film is mass-produced as a breathable packaging material for disposable diapers, wallpaper, disposable hand warmers, etc., and is cheaper than polyethylene bag materials containing fine Oya stone particles.

■Stores water bags and ethylene adsorbent along with fruits and vegetables at the same time.
By sealing and storing, it can be stored for an even longer period of time.

■Since the freshness of fruits and vegetables can be maintained for a long period of time, it is now possible to ship highly fresh fruits and vegetables at the desired time without using special equipment such as greenhouse cultivation and growing at different times. Ta.

〔Example〕

Example 1 (Storage bag) Thickness: 30μ, average diameter of micropores: approximately 1μ, moisture permeability: 200
5 g/m”・day polyethylene microporous film
It was cut to 60++n x 380mm, folded in half and heat sealed around the two sides to produce a 280mm x 380mm bag.

(Storage) Fresh apples (Jonagor) were stored in a storage bag, and the remaining side of the storage bag was sealed by heat sealing.

(Storage test) Add another 200mm x 200 bags with sealed apples.
It was stored in a mn+X200+u+ cardboard box and placed in a thermostatic machine at a temperature of 3°C±1-°C and a relative humidity of 55%±5%.

When the condition of the apples was observed every month, no changes were observed, and even after 6 months, no changes were observed in either the appearance or the pulp, and the freshness was maintained well. 8
After several months had passed, partial deterioration of the pulp began to appear for the first time.

Example 2 (storage bag) The same storage bag used in Example 1 was used.

(Water bag) A polyethylene microporous film with a thickness of 50μ and an average diameter of micropores of 1μ is overlaid with a nylon non-woven fabric, and has a moisture permeability of 1400 g/m2・day, 100x.
Two laminated sheets cut to 100 mm were stacked so that the microporous film surface was on the inside, and the periphery of the three sides was heat-sealed to make a bag. ■, Sumikagel S-50) is 10 in weight ratio
A water bag was prepared by storing 50 g of a polymeric water-absorbing agent that absorbed water at a ratio of 0:1, and heat-sealing the remaining one side.

(Storage) Store a fresh apple (jonagor) along with the water bag in the storage bag, and heat-seal the left side of the storage bag.

(Storage test) Add another 200mm x 200 bags with sealed apples.
Stored in a cardboard box of mm x 200 mm, and heated to temperature 3.
It was placed in a constant temperature and humidity chamber at a temperature of ±1°C and a relative humidity of 55% ±5%.

When the condition of the apples was observed every month, no changes were observed, and even after 7 months, no changes were observed in the appearance or pulp, and the freshness was maintained well. 9
After several months, deterioration began to appear in the pulp.

Example 3 (storage bag) The same storage bag used in Example 1 was used.

(water bag) The same storage bag used in Example 1 was used.

(Ethylene absorbent) A polyethylene microporous film with a thickness of 50 μm and a micropore diameter of 1 μm is overlaid with a nylon nonwoven fabric, and the moisture permeability is 400 g/m2・day, 100×1.
A bag was made by stacking two laminated sheets cut to 0.00 mm so that the microporous film surface was on the inside, and 10 g of activated carbon-palladium with a weight ratio of activated carbon to palladium of 1000:5 was stored in this bag. Then, the remaining one side was heat-sealed to produce an ethylene adsorbent bag.

(Storage) A water bag, an ethylene absorbent bag, and a fresh apple (
Jonagol) was stored, and the remaining side of the storage bag was heat-sealed to seal it.

(Storage test) Add another 200mm x 200 bags with sealed apples.
It was housed in a +1m x 200+u+ cardboard box and placed in a thermostatic machine at a temperature of 3°C ± 1°C and a relative humidity of 55% ± 5%.

When the condition of the apples was observed every month, no changes were observed, and even after 9 months, no changes were observed in either the appearance or the pulp, and the freshness was maintained well.

Comparative Example 1 Instead of microporous film, moisture permeability of 5 g/m"・day
When the apples were placed in a polyethylene bag with a thickness of 30 μm and the condition of the apples was observed in the same manner as in Example 1, the appearance of the apples began to change after one month. In addition, the pulp was soft and had turned brown.

Comparative Example 2 Instead of the microporous film, apples were stored in a polyethylene bag with a thickness of 30 μm and moisture permeability of 20 g/m”day containing Oya stone fine particles, and the apples were stored in the same manner as in Example 1. When the condition was observed, no change in appearance was observed even after 5 months had passed, but the pulp turned brown and no deterioration was observed.

Claims (3)

[Claims] (1) A method for preserving the freshness of fruits and vegetables, characterized by storing, sealing, and preserving fresh fruits and vegetables inside a bag using a microporous film. (2) Inside a bag made of microporous film, a water bag containing water or a water-absorbing substance soaked in water is stored in another small bag made of microporous film, and fresh fruits and vegetables at the same time. ,
A method for preserving the freshness of fruits and vegetables by sealing and preserving them. (3) Inside a bag made of microporous film, a water bag consisting of water or a water-absorbing substance soaked in water is filled in another small bag made of microporous film, and an ethylene adsorbent is filled. A method for preserving the freshness of fruits and vegetables, characterized by simultaneously storing, sealing, and preserving a drug bag and fresh fruits and vegetables.