JPH0144297B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for removing astringency from astringent persimmons, and its purpose is to remove astringency from persimmons more efficiently and easily using less alcohol, and to prevent softening and rotting of persimmons. The purpose is to prevent the occurrence of black spots. (Prior Art) Various proposals have been made to remove astringency from astringent persimmons, but generally a method of treating astringent persimmons with a lower alcohol such as ethanol has been adopted. Specifically, astringent persimmons are stacked in several layers in a container such as a cardboard box, ethanol or ethanol aqueous solution is sprayed on top of the astringent persimmons, and the container is sealed, so that the astringent removal progresses during transportation.
By the time the product reaches the point of consumption, the astringency has been completely removed. However, with this method, problems such as brown or black spots appearing on the surface of persimmons, which are not clearly known, may occur, which significantly reduces the commercial value of the persimmons, or the persimmons become too soft, and the conditions for alcohol treatment may be adjusted. The problem is that it is extremely difficult. As a countermeasure against this problem, a proposal was made to lay a breathable cushioning material on top of a soft porous material impregnated with alcohol and have ventilation holes, and to arrange persimmons on top of that and store them in a container (Japanese Unexamined Patent Application Publication No. 1983-1999).
50850), water absorption that absorbs and retains alcoholic water,
A proposal has been made (Japanese Unexamined Patent Publication No. 138339/1983) to store a water-retentive sheet together with astringent persimmons in a storage container. (Problems to be Solved by the Invention) However, according to the inventor's follow-up tests, although softening of persimmons can be prevented in JP-A-55-50850, the occurrence of black spots is difficult to avoid; 58−
138339 has also been gradually improved compared to JP-A-55-50850, but black spots still occur, and a complete solution has not been reached.
Regarding the occurrence of such black spots, the present applicant filed a patent application in 1983-
In 4468, we proposed placing a porous material impregnated with alcohol on the top layer of astringent persimmons stacked in a container via a liquid-impermeable layer. but,
Further experiments by the present inventor revealed that even with this method, it was not possible to remove astringency unless the amount of alcohol used was relatively large, and furthermore, depending on the conditions, even with this method, It has been found that there is a possibility that black spots may occur. The amount of alcohol used is closely related not only to the problem of black spots, but also to the effect of removing astringency and the time required for complete removal of astringency.Although various reports have been made in the past, In practical terms, it takes 10 days to two weeks to completely remove astringency. Also, when using such a large amount of alcohol,
There is a difficulty in controlling the astringency removal period, that is, in controlling the astringency removal period when the astringency removal is performed during transportation from the place of production to the destination. These problems, along with economic ones, must be resolved as soon as possible. (Means for Solving the Problems) However, the inventor of the present invention was able to sufficiently remove astringency in a shorter period of time even with a smaller amount of alcohol, and also solved the problems of softening and black spots. As a result of intensive research on possible methods, we focused on the structure of the container, which had not been given much attention in the past, and solved the above problem by devising the structure and the sheet impregnated with alcohol. They discovered this and completed the present invention. That is, the present invention provides a method for removing astringency from astringent persimmons by placing an alcohol-impregnated sheet on the uppermost layer of astringent persimmons stacked in a cardboard box. The inside is made of kraft paper/water-resistant film/cardboard,
and (2) the structure of the alcohol-impregnated sheet is a porous base material layer/carboxyl group-modified polyvinyl alcohol resin (hereinafter simply abbreviated as modified PVA layer/liquid impermeable layer), or The sheet is composed of a material layer/modified PVA layer/porous base material layer/liquid impermeable layer, and is characterized in that the sheet made of this structure is placed so that the surface of the liquid impermeable layer faces the astringent persimmon. Of course, in the present invention, the structure of the corrugated board base material and the structure of the sheet may basically be as described above, and even if one or more other layers are added thereto, the present invention still applies. Below, we will explain each of the corrugated boxes and alcohol-impregnated sheets.The basic composition of the base material of a corrugated box is, from the inside of the box, kraft paper/water-resistant film/cardboard.What is water-resistant film? Although not particularly limited, polyethylene film, polypropylene film, polyethylene terephthalate film, polyvinyl chloride film, polystyrene film, nylon film, etc., generally having a thickness of about 2 to 200 μm are used, and polyethylene film is particularly preferably used. The water-resistant film prevents the astringent alcohol gas from evaporating outside the container and promotes its absorption into the astringent persimmons, while also preventing the strength of the cardboard itself from decreasing due to the moisture generated by the absorption of the persimmons. For this purpose, it is essential that the water-resistant film is placed inside the cardboard.On the other hand, kraft paper absorbs the moisture caused by the persimmons to an appropriate extent and prevents water droplets from forming on the water-resistant film. The purpose is to prevent adhesion.
It is essential that the kraft paper is inside the water-resistant film. The basic composition of the alcohol-impregnated sheet is:
It must be porous substrate layer/modified PVA layer/liquid impermeable layer or porous substrate layer/modified PVA layer/porous substrate layer/liquid impermeable layer.
Both the porous substrate layer and the modified PVA layer must be made of a material that can temporarily impregnate a lower alcohol and allow the lower alcohol to evaporate under normal temperature and pressure conditions. The reason why this modified PVA is used separately from other general porous substrates is that when this modified PVA is used, the diffusion (evaporation) rate of alcohol within the box is most appropriate. Such degeneration
PVA is a resin containing about 0.2 to 15 mol% of carboxyl groups and a degree of saponification of about 70 to 100 mol%. Monomers, namely acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, monoalkyl maleate,
A method in which fumaric acid, monoalkyl fumarate, itaconic acid, monoalkyl itaconate and vinyl acetate are copolymerized and saponified, or a carboxyl group is post-reacted or grafted to general polyvinyl alcohol using an appropriate method. There are methods. Among these, monoalkyl maleate 2.0 to 10.0 mol% and vinyl acetate 98.0 to 90.0 mol%.
A copolymer with about 92.0 to 99.9 mol % of saponified material exhibits the most preferable performance. Usually, it is more efficient to use the modified PVA after heat treatment (approximately 130 to 150° C. for 60 to 180 minutes) or post-treatment such as radiation or electron beam irradiation. Porous base material layers include natural fibers, synthetic fibers, pulp, nonwoven fabrics made from pulp, crepe paper, etc., as well as plastic foams such as polyethylene, polystyrene, and polyurethane, starch, cellulose, polyacrylic acid, and polyacrylates. Any conventionally known superabsorbent resins such as crosslinked products, acrylic acid graft copolymers, etc. can be used in any combination, or two or more sheets can be stacked. The liquid-impermeable layer in the present invention is intended to prevent the alcohol impregnated into the porous material from coming into direct contact with the surface of the persimmon, so it is generally made of polyethylene, polypropylene, polypropylene, etc. with a thickness of 2.0 to 200 μm.
Plastic films such as polyvinyl chloride, polyester, and polyvinyl alcohol are used, but paper, woven fabric, and non-woven fabric that have been further treated with resin or oil can also be used. Therefore, it is desirable that the sheets composed of the porous base material layer, the modified PVA layer, and the liquid-impermeable layer are laminated so that the cross-sectional area is slightly smaller than that of the cardboard box. Porous base layer, modified
The shape of the PVA layer may be any shape other than a sheet, such as granules, lumps, strings, fibers, etc., but especially denatured
When PVA is used in the form of granules or fine powder, it can be sprayed alone on a porous substrate layer or a liquid-impermeable layer, or it can be dispersed and swollen in water or alcoholic water and then applied. The layer may be formed by a different method, or the powder may be mixed and dispersed in a resin binder and applied in order to be fixed on the layer. As the resin binder, known ones such as PVA, polyamide resin, urethane resin, etc. can be used. The thus laminated sheet can be more easily handled if the outer envelope is fixed with a heat sheet or the like, if necessary. The most practical representative example of such a sheet structure is a laminate of a nonwoven fabric made of pulp and kraft paper/modified PVA as a porous base layer.
The most preferred example is a sheet consisting of a saponified monomethyl maleate-vinyl acetate copolymer as the layer/the same porous base layer as described above/a polyethylene film as the liquid-impermeable layer. Note that an adhesive may be used between each layer if necessary. In the present invention, the purpose can be achieved with a much smaller amount of alcohol than in the past, so there is no particular need for porous inorganic fine powder, which is normally used to increase the absorption of liquid, but if necessary, it may be used in each layer. Calcium carbonate, calcium silicate, etc. may be blended with the above. The sheet thus obtained must be placed so that the liquid-impermeable layer side faces the stacked astringent persimmons. Other ways to place the sheet, such as placing the porous base layer side on the astringent persimmon side,
Further, even if the sheet is placed in the middle section or the lower section, the occurrence of black spots cannot be prevented, and the same result will occur even if no liquid-impermeable layer is used in the structure of the sheet. Incidentally, a cushioning material such as fruit net is appropriately used between the sheet and the astringent persimmons or between the persimmons. As the alcohol with which the sheet is impregnated, lower alcohols, particularly ethyl alcohol, are preferably used, and these are used as aqueous solutions with a volume concentration of 18 to 45%. The amount of the aqueous solution to be used cannot be determined unconditionally as it depends on the volume of the box, the size and number of persimmons, but it is difficult to determine the amount of persimmons to be used in an ordinary persimmon box (length 30 cm, width 37 cm, height 25 cm). 50~ in the case of stacked 4 rows vertically and 5 rows horizontally in 4 stages
A sufficient effect can be obtained with 100ml (38% by volume ethanol aqueous solution). Of course, it is also possible to use more alcohol than this amount. A sheet may be impregnated with the alcohol in advance and placed on the astringent persimmon, or a sheet may be placed on the astringent persimmon and alcohol may be sprayed onto it. . After the astringent persimmons and sheets are stored in the cardboard box, it is only necessary to seal the box to the extent that alcohol vapor does not easily escape to the outside, and it is not necessary to completely seal the box. (Effects of the Invention) By the method described above, it is possible to completely remove astringency, prevent softening, and prevent the occurrence of black spots, etc., in a short period of time and with about half the amount of alcohol used in the conventional method. Moreover, since the work can be easily incorporated into the conventional packaging work process, it is easy to carry out and has great practical value. (Example) The method of the present invention will be explained in more detail with reference to Examples below. The following cardboard boxes and sheets were prepared. However, (actual) means one having the structure of the present invention,
(Ratio) means a structure other than that of the present invention. Cardboard box (actual): From the inside of the box, the base materials are kraft paper (basis weight 50g/m ² )/polyethylene film (thickness 15μ)/double-sided corrugated paper (basis weight 760)
g/m ² ), and the size of the box is length x width x height =
30 cm x 37 cm x 25 cm Corrugated box (ratio): Same size as the above corrugated box (actual) except that the base material was commercially available 2-liner corrugated paper Sheet (actual) -1: Porous base material layer As a layer, one sheet of pulp nonwoven fabric (basis weight 60 g/m ² ) and seven sheets of crepe paper (basis weight 26 g/m ² ) are layered. / Modified PVA layer is monomethyl maleate-vinyl acetate with a carboxyl group content of 2.4 mol%. A 94.5 mol% saponified copolymer was heat-treated at 150°C for 180 minutes, and the coating amount was 40g/100g/swelled in water.
m ² (resin solid content conversion) / Nonwoven fabric as porous base layer / Polyethylene film (thickness 100μ) as liquid impermeable layer
The outermost non-woven fabric and polyethylene film are coated with a heat sheet (vertically 26 cm).
cm x Width 34cm, thickness average approximately 0.5mm) Sheet (actual)-2: Sheet (actual)-1 without using nonwoven fabric between the modified PVA layer and polyethylene film (length 26cm x width 34cm, thickness Average size: approx. 0.4 cm) Sheet (actual)-3: Carboxyl group content 4.5 mol% as modified PVA layer in sheet (actual)-1
of monomethyl maleate-vinyl acetate copolymer of
Same as the same sheet except that a sheet (100μ thick) of 95.5% mol% saponified material heat-treated at 130℃ for 120 minutes was laminated in a state in which it was swollen in water. Sheet (actual)-4: In sheet (actual)-1, the modified PVA layer was made of monomethyl maleate-vinyl acetate copolymer with a carboxyl group content of 2.1 mol%.
94.1% mol% saponified material was humidified to a water content of 25.6% by weight and irradiated with an electron beam of 7.5 Mrads, and the same sheet was fixed with a PVA binder at a coating weight of 54g/ ^m2 . same. Sheet (ratio)-1: Sheet (actual)-1 without a polyethylene film layer Sheet (ratio)-2: Sheet (actual)-1 with starch-acrylic acid graft copolymer without using modified PVA Examples 1 to 4 using merging Astringent persimmons were stacked in the cardboard box (fruit) in three tiers, with the first to third tiers from the top of the cardboard box being 4 rows vertically and 5 rows horizontally as one tier, and the bottom of the box, In other words, for the fourth row from the top, pack 90 pieces in total, 5 rows vertically and 6 rows horizontally, and place sheets (fruit) 1 to 4 on top of the top layer of astringent persimmons, with the liquid-impermeable layer side facing the astringent persimmons. was placed on the sheet, and an aqueous ethyl alcohol solution having a concentration of 38% by volume was sprinkled on the sheet in the amount shown in Table 1, and the sheet was sealed. This was left at room temperature and opened after 7 days, and the extent of astringency removal and the occurrence of black spots were examined. Example 1~
Set it to 4. The results are shown in Table 1. Comparative Examples 1 to 4 A cardboard box (actual) was used as the container, but
Sheet (Ratio)-1 was used as a sheet (Comparative Example 1), Sheet (Ratio)-2 was used (Comparative Example 2), Sheet (Fruit)-1 was used with the porous base layer side being astringent persimmon. (Comparative Example 3), the sheet (actual)-1 was placed with the liquid impermeable layer side down,
And an experiment similar to the example was conducted for the persimmons placed between the second and third tier persimmons (Comparative Example 4).
The degree of astringency removal and the occurrence of black spots were investigated. The results are shown in Table 2. Comparative Examples 5 and 6 Using a cardboard box (ratio) as the cardboard box,
In addition, the same examination was conducted using Sheets (fruit)-1 and 2 (the liquid-impermeable layer was placed on the side of the persimmon).

[Table] Judged.

[Table] * In Comparative Example 3.4, the way the sheets were placed was different from the example.
☆ Same as Table 1

Claims (1)

[Scope of Claims] 1. A method for removing astringency from astringent persimmons by placing an alcohol-impregnated sheet on the top layer of astringent persimmons stacked in a cardboard box, which includes the following steps: (1) The structure of the base material of the cardboard box is , the inside of the box is made of kraft paper/water-resistant film/cardboard,
and (2) whether the structure of the alcohol-impregnated sheet is a porous base layer/carboxyl group-modified polyvinyl alcohol resin layer/liquid impermeable layer;
Or, it consists of a porous base material layer / a carboxyl group-modified polyvinyl alcohol resin layer / a porous base material layer / a liquid impermeable layer, and the sheet made of this structure is made such that the surface of the liquid impermeable layer is the astringent persimmon side. A method for removing astringency from astringent persimmons, which is characterized by placing the astringent persimmons on.