JPS6126332B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for removing astringency from persimmons. Traditionally, the method of removing the astringency from persimmons has been to treat them with ethyl alcohol. Persimmons obtained by removing astringency from alcohol are popular among consumers due to their smooth flesh and juicy texture. However, it has the disadvantage of short shelf life and softening, and in addition, black spots appear on the surface of the persimmons due to excessive humidity inside the cardboard boxes during distribution, resulting in so-called fruit contamination, which significantly reduces the product value. Ta. Recently, the method of removing astringency from persimmons using carbon dioxide gas has become popular mainly in western Japan. Contrary to the alcohol removal method, the astringency removal method using carbon dioxide has the advantage that the persimmons are hardened and the astringency removal time is short and can be removed in just two days and nights. However, the method of removing astringency using carbon dioxide gas is inferior to the method of removing astringency with alcohol in terms of taste, and, like the method of removing astringency with alcohol, it also has the disadvantage of producing black spots due to excessive humidity. Therefore, the present inventors conducted intensive research to solve these drawbacks, and found that by using a super absorbent polymer, it is possible to avoid the overhumidity state during astringency removal, and it is possible to remove astringency without the above-mentioned drawbacks. They discovered this and completed the present invention. That is, the present invention provides a method for removing astringency from persimmons, which is characterized in that a highly water-absorbing polymer is present when removing astringency from persimmons using ethyl alcohol or carbon dioxide gas. In particular, the present invention relates to a method for removing astringency from persimmons, which is characterized by placing a persimmon in a container and removing astringency using ethyl alcohol or carbon dioxide gas, which is characterized by the presence of a superabsorbent polymer in the container. By the method of the present invention, contamination and softening of the fruit due to removal of astringency from persimmons can be prevented, and freshness can be maintained for a long period of time. Here, the method of the present invention is effective for any type of persimmon as long as it is a so-called "astringent persimmon." It is effective for The superabsorbent polymer according to the present invention is a substance that is insoluble in water, absorbs a large amount of water when it comes into contact with water, and has a water absorption capacity of 100 times or more its own weight.
Starch-polyacrylonitrile graft copolymer disclosed in Japanese Patent Publication No. 43395, cross-linked polyalkylene oxide disclosed in Japanese Patent Publication No. 51-39672,
Saponified vinyl ester-ethylenically unsaturated carboxylic acid copolymer disclosed in Japanese Patent Publication No. 53-13495, self-crosslinked polyacrylate obtained by reversed-phase suspension polymerization method disclosed in Japanese Patent Publication No. 54-30710 , a reaction product of a polyvinyl alcohol polymer and a cyclic acid anhydride disclosed in JP-A No. 54-20093,
Examples include crosslinked polyacrylates disclosed in JP-A-55-84304. A particularly preferred superabsorbent polymer is a self-crosslinked polyacrylate having a water absorption capacity of 100 times or more its own weight. The shape of the superabsorbent polymer used in the present invention is not particularly limited, and shapes such as powder, granules, granules, blocks, scales, and sheets can be used. The amount of super absorbent polymer used depends on the variety of persimmon, ripeness,
Although it varies depending on the packaging state and the temperature during storage or distribution, the amount is 0.01 to 1% by weight based on the fresh weight of persimmons. In carrying out the present invention, the superabsorbent polymer can be formed into pellets, beads, rods, blocks, sheets, etc. and used. When making a sheet, it is sandwiched between paper sheets, attached to paper,
You can also use methods such as paper cutting. In the present invention, "to remove astringency with ethyl alcohol or carbon dioxide gas" means to remove astringency by placing persimmons in an atmosphere of ethyl alcohol or carbon dioxide gas, and when using ethyl alcohol, directly apply ethyl alcohol. Various methods can be considered, such as spraying on persimmons, placing an ethyl alcohol-impregnated body in a container and creating an ethyl alcohol atmosphere by evaporation, and introducing ethyl alcohol into a gaseous state into the container. Typically, ethyl alcohol is applied as a 0.1 to 80 volume percent aqueous solution. Preferably 10-50
A volume percent aqueous solution is used. in this case,
The amount of the aqueous ethyl alcohol solution to be sprayed varies depending on the degree of sealing of the container, but is usually 50 to 500 ml and preferably 80 to 300 ml per 15 kg of persimmons. Another method is to impregnate a molded superabsorbent polymer with an aqueous ethyl alcohol solution and place it in a container containing persimmons. When using carbon dioxide gas, it is usually desirable to keep persimmons at a concentration of 90% or more. An example of an embodiment of the present invention is as follows. When using ethyl alcohol, a sheet of super absorbent polymer and cardboard is placed between each tier of persimmons to serve as a cushion, packed in a cardboard box, sprinkled with an aqueous solution of ethyl alcohol, closed with a lid, and then placed in a cardboard box. Get rid of astringency for 20 days. During this period of desistance, it will be placed in circulation. During distribution, the astringency has progressed and it is rational. When using carbon dioxide gas, the warehouse containing persimmons is filled with carbon dioxide gas to remove astringency over two days and nights, and at that time a super absorbent polymer is present, or the persimmons are placed in a cardboard box and a super absorbent polymer is present. The dried products are placed in a warehouse filled with carbon dioxide gas to remove astringency. After the astringency is removed, it is placed in circulation as is. By using the astringency removal method of the present invention, it has become possible to remove astringency while maintaining freshness. In addition, when distributing persimmons that have been removed from astringency, if a super absorbent polymer is present in the container filled with persimmons,
The present inventors have discovered that it is possible to suppress the subsequent decrease in commercial value such as the occurrence of black spots. In particular, persimmons that have been de-astringent using the carbon dioxide method are susceptible to black spots due to excessive humidity during distribution, so when persimmons that have been de-astringent with carbon dioxide are placed in cardboard boxes for distribution, superabsorbent polymers are used. , it is good to have the already mentioned amount exist. Further, in carrying out the present invention, it is also possible to use a conventionally known gas absorbent together with the superabsorbent polymer and to have these present in the container. As a gas absorbent, for example, to lower the oxygen concentration in the container,
Reduced iron powder, iron-based oxygen absorbers such as ferrous sulfate, etc. are used to adsorb organic gases such as ethylene and alcohol generated during the ripening process of persimmons, such as activated carbon,
Molecular sieves, zeolites, etc., and inorganic carriers of these with potassium permanganate, palladium, etc. adsorbed can be used.
The amount of gas absorbent used varies depending on the variety of persimmon, ripeness, packaging condition, temperature, etc., but generally it is 0.005 to 10% of the fresh weight of persimmon, preferably 0.05%.
~1%. In such cases, persimmons are essentially sealed in a non-breathable packaging material, but there are various types of plastic films that can be used as non-breathable packaging materials.
Examples include stretched nylon, polyester, moisture-proof cellophane, vinylidene chloride, MX nylon, vinyl chloride, and ethylene/vinyl alcohol copolymer. By using the astringency removal method of the present invention, the following effects can be obtained. By encapsulating a super absorbent polymer that has adsorbed an aqueous ethyl alcohol solution with astringent persimmons, or adding a super absorbent polymer after treating with an aqueous ethyl alcohol solution, there is no negative effect on the astringent removal effect, and ethyl alcohol and its oxidation Due to the action of the substance acetaldehyde, soluble tannins change to insoluble tannins, removing the astringency. At that time, the presence of super absorbent polymers can prevent over-humidity inside the packaging, and as a result, it prevents black spots that occur on the surface of the fruit, which is a physiological disorder caused mainly by over-humidity, and also suppresses the softening of the fruit. be done. During distribution, it is possible to prevent the cardboard from softening, and use water-repellent cardboard lined with polystyrene, ethylene vinyl alcohol copolymer film, etc. Further, even when removing astringency using carbon dioxide gas, abnormal overhumidity in the astringent storage can be prevented. Furthermore, it was found that by storing persimmons together with a gas absorbent and a superabsorbent polymer in a plastic packaging material, there was no deterioration in quality over a long period of time and the product value was not impaired. EXAMPLES Hereinafter, the features and effects of the present invention will be specifically illustrated through Examples, but the present invention is not limited to these Examples. Example 1 Five persimmons (produced in Wakayama, without flat seeds) (approximately 1 kg) were made of non-porous plastic (KOP (vinylidene chloride/
After spraying a 35% (V/V) ethyl alcohol aqueous solution with an 8 ml spray gun in a packaging material of propylene copolymer)/PE (polyethylene), A paper sheet (12 x 20 cm) (salt, absorption rate: 500 times) was placed, folded in half, and stored at 5°C and 20°C. A newspaper supplemented area was set up as a control area. 5℃ is 30 days later, 20℃
were opened and examined after 10 days. The survey items were astringency, blackening, hardness, and physiological disorders inside the fruit. Astringency is a sensory test.
Black discoloration and physiological disorders were determined visually and expressed using the following evaluation criteria. The hardness was determined by cutting the persimmon horizontally, measuring the hardness at two locations per piece using a universal hardness meter, and calculating the average value. Note that a cylindrical head needle with a diameter of 5 mm was used. The results are shown in Tables 1 and 2. Astringency Taste -: No astringency ±: Slightly astringent +: Astringent ++: Strong astringency Blackened fruit -: No blackened ±: Slightly blackened +: Obviously blackened ++: Significantly blackened Physiology inside the fruit Obstacle -: No +: Yes

【table】

[Table] Example 2 Five persimmons (produced in Wakayama, without flat seeds) (approximately 1 kg) were placed in a non-porous plastic (KOP) packaging material, and
ml of 35% (V/V) ethyl alcohol aqueous solution on paper sheets (12 x 20
cm), stored at 20°C, and examined over time.
The survey items were astringency, blackening, and hardness.
The investigation method was the same as in Example 1. The results are shown in Table 3.

[Table] Example 3 Five pieces (approximately 1 kg) of persimmons (produced in Wakayama, without flat seeds) were placed in a non-breathable plastic (KOP) packaging material.
% (V/V) ethyl alcohol aqueous solution with a spray gun, super absorbent polymer (self-crosslinking polyacrylate) paper sheet g (effective amount equivalent) and de-ethylene agent (New Green Patsukurengo Co., Ltd.) Add 1 bag, seal completely, and store at 5℃ for 2 hours.
Saved for months. As control plots, a plot in which a deethyleneizing agent was used alone and a plot in which no superabsorbent polymer was added were set up. The survey items were astringency, blackening, and hardness. The results are shown in Table 4.

[Table] Example 4 80 persimmons (produced in Wakayama, without flat seeds) (approximately 15 kg) were stacked in four tiers in cardboard boxes (31 x 36 x 26 cm). Paper sheets (30 x 35 cm) containing three types of super absorbent polymers with different contents (self-crosslinking polyacrylate, absorption rate 500 times) are spread on the top layer, and 150 ml of 38% (V/V) ethanol aqueous solution is placed on top. I sprayed it. On this occasion,
To avoid contact between the paper sheet and the persimmons, I placed a sheet of vinyl chloride between them as a cushioning material. After spraying, the fruit was immediately sealed and stored at 25°C for 10 days, and each stage was examined for astringency, blackening, and hardness. In addition, a normal spray area was set up as a control area. The results are shown in Table 5.

【table】

[Table] Example 5 80 persimmons (produced in Wakayama, without flat seeds) (approximately 15 kg) were stacked in four layers in cardboard boxes (31 x 36 x 26 cm). A sheet of 38% (V/
V) Sprayed 150ml of ethanol aqueous solution. There are two types of sheets: paper sheet 1 as shown in Figure 1 and polyethylene laminate type sheet 2 with absorption on one side as shown in Figure 2.The content of super absorbent polymer is
It was 50g/ ^m2 . At this time, in order to avoid contact between the sheet 1 or 2 and the persimmon 3, and as a cushioning material, a vinyl chloride net 4 was placed between them. After spraying, the seeds were immediately sealed and stored at 20°C for 14 days, and the astringency, hardness, and blackening of the fruits were examined. The results are shown in Table 6.

【table】 [Brief explanation of the drawing]

1 and 2 are cross-sectional views of cardboard boxes stuffed with persimmons used in the test of Example 5. 1... Paper sheet containing super absorbent polymer, 2...
Super absorbent polymer-containing polyethylene laminate sheet, 3... persimmon, 4... chloride vinyl.

Claims (1)

[Claims] 1. When removing astringency from persimmons with ethyl alcohol or carbon dioxide gas, add 0.01 to 1% of a super absorbent polymer with a water absorption capacity of 100 times or more of its own weight to the weight of the persimmons.
A method for removing astringency from persimmons characterized by the presence of % by weight.