JP2634557B2 - How to remove astringency on persimmon trees - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing astringent persimmons, and more particularly to a method for removing persimmons from a persimmon before harvesting.

[0002]

2. Description of the Related Art Persimmons include so-called sweet persimmons and astringent persimmons. Of these, astringent persimmons contain tannins, which are astringent components, in fruits and exhibit astringency. As a method for removing astringency from astringent persimmons, there are known a method of removing dried persimmons, a method of removing hot water, a method of removing alcohol, and a method of removing carbon dioxide. Such desweetened and sweetened ones are called "Sawashi persimmons".

[0003] For example, alcohol removal method (barrel scouring method)
Lay a straw on the bottom of the barrel, stuff the persimmon, sprinkle with shochu,
Cover the area with a lid. In this method, alcohol is converted into acetaldehyde by an enzyme in the fruit, and tannin, astringent component, reacts with acetaldehyde to change into a water-insoluble colloid and loses astringency.

However, dried persimmons are remarkably different in shape, texture and texture from persimmons immediately after harvest. In addition, sashimi persimmon obtained by another method becomes a so-called ripe persimmon-like soft persimmon, and has a disadvantage that it is easily damaged or damaged during the distribution stage.

[0005] For this reason, a method of removing astringent trees from persimmons before harvesting has been devised. In this method, a persimmon before ripening is covered with a plastic bag, and solid alcohol is put in the bag and sealed. The sealing treatment with solid alcohol is usually performed for about 6 to 12 hours, and harvested 5 to 10 days after the treatment. The plastic bag used here is made of a polyolefin-based film such as polyethylene or polypropylene in consideration of the hermeticity of alcohol and gas barrier properties.

[0006] The above-mentioned method of removing astringent trees has the advantage that persimmons that are not softened can be obtained. However, in this method, the moisture evaporating from the persimmon is trapped in the bag and becomes over-humidified, and the moisture condenses on the inside of the bag or on the surface of the persimmon. And the appearance of persimmons may be significantly impaired. For this reason, the problem that the commercial value of the persimmon obtained may fall remarkably is pointed out.

[0007]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, have found that the above problems can be solved by using a wrapper made of a polyvinyl alcohol-based sheet. The present invention has been completed. An object of the present invention is to provide a persimmon tree-removing method for removing persimmons efficiently without causing defects in appearance from persimmons before harvesting.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for removing persimmons from persimmons by covering the persimmon nuts before harvesting with a wrapping bag and sealing solid alcohol with the persimmon berries in the wrapping bags. ,
This is achieved by a method for removing persimmons on a tree, wherein the wrapper is made of a polyvinyl alcohol-based sheet.

The wrapper used in the present invention is formed of a sheet of polyvinyl alcohol resin and has a shape capable of completely covering persimmon fruit. As the polyvinyl alcohol-based resin, for example, a completely or partially saponified polyvinyl alcohol having a degree of polymerization of about 300 to 3000, or a polyvinyl alcohol modified by introducing a certain functional group as a side chain into a thin film is used. Can be mentioned.

The polyvinyl alcohol-based sheet used in the present invention may be a non-stretched film, but is preferably a film stretched in a uniaxial or biaxial direction and subjected to a heat treatment.

An unstretched film obtained by simply forming polyvinyl alcohol into a film is extremely excellent in water absorption,
Lack of water resistance, large swelling when wet, and large shrinkage due to repeated moisture absorption and release. In this respect, the polyvinyl alcohol film subjected to the stretching heat treatment has good water resistance and good dimensional stability, and is practically preferable. The stretching heat treatment conditions include a stretching ratio of 5 to 7 times and a heat treatment temperature of 200 to 230.
C is preferable in that a good effect can be obtained.

Above all, a film that has been subjected to a biaxial stretching heat treatment is preferred because it has improved strength directionality and is less susceptible to breakage, so that it is easy to handle. In addition, a sheet-like material in which small cuts are alternately inserted in the stretching direction to form a split web, or a split web obtained by widening the split web and a film subjected to stretching heat treatment, is excellent in flexibility, and is excellent in detachability. It does not damage the persimmon, and is also excellent in controlling the humidity inside the wrapper.

In order to remove persimmon by the method of the present invention, first, the persimmon before ripening, which is a tree, is covered with the above-mentioned wrapping bag, and an alcohol source such as solid alcohol is stored therein. The mouth of the wrapper is tightly closed, and the persimmon and the alcohol source are sealed in the wrapper. This state is, for example, 6 to 2
What is necessary is just to hold for about 4 hours.

[0014]

[Function] Since the polyvinyl alcohol-based sheet material forming the wrapper has an excellent effect of shielding the alcohol component,
The alcohol component evaporated from the alcohol source fills the wrapper. This alcohol component is absorbed by persimmon, and is then astringently removed by the same action as the conventional alcohol removal method.

Further, the polyvinyl alcohol-based sheet material is rich in hydrophilicity, and the moisture evaporating from the persimmon is once absorbed by the wrapper and then released to the outside. For this reason,
No water drops on the inside of the zipper or persimmon surface. Therefore, it is possible to prevent the adverse effects that are considered to be caused by water droplets that reach the surface of the persimmon.

Further, since the polyvinyl alcohol-based sheet material has good translucency and excellent infrared absorbing ability,
It has an excellent heat retention effect not found in polyolefin films. For this reason, according to the method of the present invention, the secondary effect of accelerating the ripening of fruits is also exhibited.

[0017]

【Example】

Example 1 A wrapper made of a 50 μm thick unstretched polyvinyl alcohol film and having a length of 30 cm and a width of 20 cm was prepared. The wrapping bag was put on the persimmon fruit which had begun to color slightly, solid alcohol was put in the wrapping bag, and the mouth of the wrapping bag was closed. After being left for about one day in this state, the wrapper was removed. One week later, the persimmon berries that had been subjected to the astringent treatment were harvested. The harvested persimmon had astringency and was very good in appearance.

Example 2 The wrapping bag used in Example 1 was replaced by a polyvinyl alcohol-based biaxially stretched film having a thickness of 25 μ instead of the polyvinyl alcohol-based unstretched film.
In the same manner as in Example 1, persimmon berries were subjected to astringent removal treatment. The harvested persimmon had astringency and was very good in appearance.

Example 3 The wrapping bag used in Example 1 was divided into a polyvinyl alcohol-based biaxially stretched film having a thickness of 18 μm and a polyvinyl alcohol-based uniaxially stretched film instead of the polyvinyl alcohol-based unstretched film. A persimmon fruit was subjected to astringent removal treatment in the same manner as in Example 1 except that a sheet-like material on which the split web was laminated and fixed was used. The harvested persimmon had astringency and was very good in appearance.

[0020]

According to the method of the present invention, since the astringent persimmon can be effectively removed from the persimmon on the tree before harvesting, the persimmon obtained cannot be seen by the conventional method of obtaining persimmon persimmon. It has good firmness and fresh texture.

In the method of the present invention, since a polyvinyl alcohol-based sheet is used as a material for the wrapper,
It is possible to prevent various adverse effects on persimmons, which are considered to be caused by water droplets, which are observed in the conventional tree-removing astringent method, so that persimmons having a good appearance can be obtained. The persimmon obtained by the method of the present invention is less damaged and less painful in the distribution process, has excellent quality, and has high commercial value.

Claims (2)

(57) [Claims] 1. A method of covering a persimmon fruit before harvesting with a wrapping bag, sealing solid alcohol together with the persimmon fruit in the wrapping bag, and removing the persimmon from the astringent, wherein the wrapping bag is formed of a polyvinyl alcohol-based sheet. A method for removing astringency on a persimmon tree, characterized by being made of material. 2. The method for removing persimmon trees according to claim 1, wherein the envelope is made of a sheet obtained by subjecting a polyvinyl alcohol-based film to a stretching heat treatment.