JPH04112779A - Peeling treatment of japanese chestnut and peeling treatment device therefor - Google Patents

Abstract

PURPOSE:To obtain peeled Japanese chestnuts suitable for Marrons glaces, etc., readily peelable, having a high yield free from loss such as nut crack during boiling in water or flavoring and processing by treating Japanese chestnuts with chestnut burs with a chemical solution and irradiating with microwave. CONSTITUTION:Japanese chestnuts with chestnut burs or Japanese chestnuts from which chestnut burs are completely or incompletely peeled are treated with preferably 0.5-10% aqueous solution of hydrochloric acid. Then the Japanese chestnuts are irradiated with microwave in such a way that the microwave intensity is large at the initial stage and then gradually lowered and then the softened and weakened chestnut burs are peeled to give the objective Japanese chestnuts.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for peeling chestnuts.

[Conventional technology] Conventionally, in order to use chestnuts as raw materials for processing marron glacé, chestnuts, and other confectionery, it is necessary to remove the skin and astringent skin of the chestnuts in advance, but the mainstream method is to peel raw chestnuts directly with a knife. ing. On the other hand, before peeling, pectin is eluted by heating the chestnuts in hot water, externally heating them with steam or steam, or heating them with a chemical solution consisting of hydrochloric acid or an aqueous acid solution mainly composed of hydrochloric acid, and the pulp and astringent skin are removed. It has been proposed to carry out a preliminary treatment to loosen the bonds with the skin, that is, a peeling process.

[Problem to be solved by the invention]

The conventional method of removing the skin and astringent skin from chestnuts using a direct knife is as follows:
This method requires a lot of labor and time, has extremely low peeling efficiency, and has the disadvantage that the yield after peeling is extremely low at around 50%.

Therefore, it is unsuitable for confectionery processing, such as Maron Gras and V-Se, where the texture of the pulp is important.

Even with the various external heating and chemical treatments described above, the separation of the pulp and astringent skin is insufficient, and although the skin can be easily peeled off, it is necessary to remove the astringent skin with an auxiliary tool such as a knife. In order to improve the peeling rate, increasing the concentration of hydrochloric acid and prolonging the heat treatment time will result in deterioration of the quality of the pulp, increase the elution of components in the astringent peel, and require special measures for wastewater treatment. With inconvenience, besides, # of pulp! The damage and softening become large and the pulp collapses during peeling, resulting in a poor yield.Furthermore, the peeled pulp is generally stored in cold water or frozen for a few days before being boiled in water or subjected to seasoning processing. However, this process also increases the rate of disintegration, especially
Approximately 30% of new chestnuts break down, resulting in increased product loss.

On the other hand, with conventional external heat treatment, the outer layer of the chestnut pulp becomes soft, but the center becomes undercooked.
As a whole, the pulp becomes distorted due to heating, and when peeling, the pulp collapses and the flesh cracks, resulting in a decrease in yield.Furthermore, the flesh tends to crack during boiling and seasoning processing, resulting in the production of processed products such as marron glacé. bring loss.

[Means to solve the problem]

In view of the above-mentioned disadvantages of the conventional peeling method, the present invention facilitates peeling and improves the yield during peeling,
Furthermore, it provides a method for peeling chestnuts that reduces loss due to splitting and disintegration during boiling, seasoning, and is suitable for producing processed chestnuts such as marrons classé. The method is characterized in that a desired amount of chestnuts or chestnuts from which the skin has been completely or incompletely removed is treated with a chemical solution and then subjected to microwave irradiation treatment.

Furthermore, the present invention provides an apparatus for carrying out the method for peeling chestnuts described above, which comprises a container provided with a large number of through holes, a chemical tank,
It consists of a processing chamber that seals or semi-hermetically accommodates the porous container, a microwave irradiation device connected to the processing chamber, and a motor or handle transfer means for rotating the porous container accommodated in the processing chamber.

[For production]

T-chestnuts with skins or chestnuts from which skins have been completely or incompletely removed are treated with a chemical solution to elute pectin and loosen the bond between the astringent skin and the pulp. When microwaves are irradiated in this state, the microwave has a deep penetration distance, so the chestnuts are heated evenly from the inside of the pulp to the surface, and some of the water contained in the pulp becomes water vapor on the surface of the pulp. When released from the pulp, it acts to peel off the loosely bound astringent skin from the pulp surface, while the pulp heat shrinks due to the release of steam. In this way, a gap is created between the surface of the pulp and the astringent skin, and the entire pulp is heated uniformly without distortion.

By applying light external forces such as friction to chestnuts treated by the above-mentioned treatment method of the present invention, the astringent skin can be easily removed.
Fruit pulp having a texture with reduced pulp cracking and pulp disintegration rate can be obtained at a high yield.

In addition, the peeled chestnuts obtained by this process can be peeled chestnuts with firm flesh without distortion, resulting in seasoning products with no or almost no cracking in the flesh during boiling, seasoning, etc.

In this case, in the chestnut peeling method of the present invention described above, the chemical solution is an acid aqueous solution, and after treating the chestnuts with the chemical solution, the neutralization treatment can be performed before or after the microwave irradiation treatment.
It is more preferable to perform microwave irradiation treatment after neutralization treatment. In this case, the sodium ions contained in the
Absorbs microwaves and promotes the exfoliation effect of fruit pulp and astringent skin.

When using a hydrochloric acid aqueous solution with a relatively low concentration of approximately 0.5 to 10%, high-quality fruit pulp can be obtained without deterioration of quality, while elution of soluble components from the skin and astringent skin is reduced. can. Furthermore, it is preferable to treat the fruit with an aqueous hydrochloric acid solution prepared by adding a chelating agent such as sodium hexametaphosphate to the aqueous acid solution, since this can prevent stickiness on the surface of the pulp and elution of skin components.

Also, when using an acid aqueous solution with a surfactant added to it, even if the skin is completely attached, the acid aqueous solution can pass through this and reach the astringent skin. The peeling process can be carried out well. Furthermore, when using an acid aqueous solution containing an oxidizing agent, the skin can be oxidized and weakened by subsequent microwave irradiation, improving the peeling effect.

In the microwave irradiation treatment, by performing the microwave irradiation treatment on a desired amount of chemically treated chestnuts while rolling them, each chestnut can be more uniformly irradiated and heated with microwaves. In addition, when processing desired chemically treated chestnuts in a batch process or in an assembly line process, by irradiating them with microwaves in a closed or semi-closed environment, the water vapor emanating from each chestnut can be absorbed without escaping to the outside. The chestnuts are surrounded by the water vapor,
Chestnut skin or astringent skin can be thermally swollen and softened, thereby promoting the peeling effect.

Microwave irradiation is carried out continuously or intermittently for a predetermined period of time, but if the irradiation dose is initially greatly reduced gradually, the pulp can be softened well, further preventing disintegration and cracking. Furthermore, according to the chestnut peeling apparatus of the present invention, the chestnut peeling process can be performed consistently using the porous container. That is, put a desired amount of chestnuts in the container,
When immersed in a chemical solution tank, the chemical solution enters the container through these holes, and the container is pulled up at the 9th stage, which enables chemical processing of chestnuts, and the container is placed in a closed or semi-closed processing chamber. If the microwave irradiation is performed while rotating the porous container, each chestnut will roll and the microwave irradiation can be performed uniformly.

Furthermore, when a neutralizing agent liquid tank is further added to the apparatus, it is generally preferable to neutralize the acid aqueous solution before or after the microwave irradiation treatment.

〔Example〕

Next, examples of the present invention will be described in detail.

The present invention can be applied to all kinds of chestnuts with different varieties, ripeness levels, storage periods, etc. Chestnuts selected as appropriate, with devilish skin attached.
1 or a chestnut whose skin has been partially opened by piercing or cutting so that the medicinal solution can easily reach the astringent skin, or a chestnut whose skin has been completely removed is used as the raw material to be processed. Partial or complete removal of the demon skin is performed using a knife or mechanical force. A desired amount thereof is placed in, for example, a mesh basket and immersed in a chemical bath. As the chemical solution, an acid aqueous solution is generally used.

As the acid, hydrochloric acid is generally used, and other inorganic acids or various organic acids such as phytic acid, which are not harmful to human consumption, are selectively used. Further, an acid aqueous solution is used, in which one or more additives selected from chelating agents such as sodium hexametaphosphate, penetrating agents such as surfactants, oxidizing agents, etc. are appropriately added. Of course, the concentration of the acid aqueous solution used conventionally is effective, but according to the treatment method of the present invention, since microwave irradiation treatment is performed afterwards, the concentration of the acid aqueous solution can be made thinner than that, and the immersion time is also short. In the case of an aqueous hydrochloric acid solution, a range of 0.5 to 10% is sufficient, and the time for soaking chestnuts in this solution is longer than the conventional 1. /2 or less is sufficient.

Further, the temperature of the chemical solution during immersion may be unheated, that is, room temperature, or even if heated, it only needs to reach about 80°C.

In this way, a desired amount of chestnuts is immersed for a short time in, for example, a 10% or less hydrochloric acid aqueous solution, and the astringent skin of the chestnut is treated with a chemical solution to elute pectin and loosen the binding force between the astringent skin and the pulp surface.

The concentration of the immersion in the aqueous hydrochloric acid solution, the immersion time of the chestnuts, etc. are adjusted as appropriate depending on the variety, ripeness, storage period, etc. of the chestnuts to be treated. Usually, it is immersed in several percent hydrochloric acid aqueous solution for several minutes.

After immersion, it is pulled out, and then it is immersed for a short time in a neutralizing agent liquid tank, and after neutralization treatment, it is generally subjected to microwave irradiation, or it is generally used to apply microwave irradiation immediately after the acid immersion treatment. It also has a peeling effect. As the neutralizing agent, an aqueous solution containing sodium ions such as soda carbonate, sodium bicarbonate, and caustic soda is generally preferred. In this case, it was found that the sodium ions absorb microwaves in the next microwave irradiation treatment step, raise the surface temperature of the chestnut, and thereby improve the effect of peeling off the astringent skin.

In addition, by increasing the pH of chestnuts to a range of 5 to 7 through neutralization, softening of the pulp can be promoted. For neutralization treatment, immersion for seconds is sufficient.

According to the present invention, the chestnuts that have been treated with a chemical solution to loosen the bond between the astringent skin and the pulp are subjected to microwave irradiation treatment.

The microwave irradiation is preferably performed continuously or intermittently for a predetermined period of time, and the irradiation mode is preferably such that the irradiation amount is large at the beginning of the irradiation and then reduced.

Since the microwave irradiation uniformly heats the chestnut pulp from the center to the surface, the entire chestnut pulp is heated and softened without distortion. During this time, the water vapor generated from inside the pulp emanates from the surface of the pulp and acts to peel off the astringent skin, whose binding force with the pulp has weakened due to the previous chemical treatment, and thereby to separate the astringent skin and pulp. Water vapor enters the pores of
Furthermore, ensure separation between the two. At the same time, microwaves, which have a deep radio wave penetration distance, allow some of the water vapor contained in the fruit to escape and dry evenly from the center to the surface of the fruit.
This is accompanied by a phenomenon in which the entire fruit pulp uniformly dehydrates and shrinks, further promoting the separation of the fruit pulp and astringent skin. Thus, microwave irradiation after chemical treatment brings about the effect of exfoliating the astringent skin.

Furthermore, the microwave irradiation and heating tightens the entire fruit pulp, thereby preventing the pulp from disintegrating and cracking during peeling, boiling, etc. Needless to say, the microwave irradiation time and output should be adjusted appropriately in consideration of the variety of chestnuts to be treated, ripeness, storage period, etc.

Microwave irradiation treatment enables uniform heating to the center of the fruit pulp, so if necessary, it is possible to perform heating irradiation to soften the fruit to the center and make it edible. It is also possible to omit part or all of the boiling step. In this regard, in conventional external heat treatment, if the center of the fruit is heated until it is edible, the outer layer of the fruit becomes too soft and becomes sticky on the surface of the fruit, and furthermore, the pulp collapses during peeling. This results in a significant increase in yield and product value. Therefore, when the outer layer of the pulp is softened appropriately in order to increase its yield, the inside becomes undercooked. Therefore,
- Even if it is boiled in water after being frozen and stored, the inside of it does not soften and becomes so-called a solidified state, making it unsuitable for consumption.The microwave irradiation treatment of the present invention may Conventional problems can be solved.

Further, it is preferable that the microwave irradiation treatment is carried out in a closed or semi-closed condition. That is, a desired amount of chestnuts is housed in a closed or semi-closed processing chamber, or is housed in a perforated pipe and sealed or semi-closed. The water vapor generated when irradiating this with microwaves is trapped in the processing chamber or pipe, so
It is possible to generate a thermal environment using water vapor around the chestnuts, and therefore, by irradiating the chestnuts with microwaves in such an environment, it is possible to promote the heating and softening of the bitter skin and the astringent skin.

Furthermore, when performing microwave irradiation, a large number of chestnuts may be placed in a porous container and the container may be rotated continuously or intermittently by a motor or handle, or the chestnuts may be transferred using a screw conveyor and the chestnuts may be irradiated with microwaves. It is preferable to use a transfer means such as applying a beam to the beam, since the entire beam can be uniformly irradiated and heated one by one.

As the microwave irradiation device, ■batch type microwave heating, ■general-purpose conveyor type microwave heating machine, ■cylindrical screw conveyor type microwave heating machine, ■vibrating pipe type microwave heating machine, etc. can be used.

Further, the method for peeling chestnuts of the present invention can be carried out either in a batch method or in a continuous method in an assembly line.

The chestnuts that have been irradiated with microwaves in this manner are preferably placed in an aquarium next. As a result, the pulp shrinks upon cooling, further promoting separation from the astringent skin, and at the same time, if the fruit has a bitter skin, it softens by absorbing water together with the astringent skin, making subsequent peeling easier.

In addition, when performing a neutralization treatment after microwave irradiation, the neutralization treatment can be carried out by instantaneous immersion in a neutralizing agent solution bath containing a neutralizing agent. Note that, instead of using a neutralizing agent, the acid may be removed by immersing the treated chestnuts in a water tank or by exposing them to running water.

The output and irradiation time when using the microwave irradiation equipment described in (1) to (3) above are generally varied depending on the chemical treatment conditions described above, and also depending on the variety, size, and storage period of the chestnuts. Considering the differences in water content of chestnuts due to differences,
After finding appropriate processing conditions, it is preferable to store the processing conditions in a microcomputer and control them electrically.

Next, Table 1 below shows the approximate immersion times for treating chestnuts with skins removed and chestnuts with skins in hydrochloric acid aqueous solutions having various concentrations, respectively.

In addition, in the case of chestnuts with extremely long storage times and hardened skin, either the whole chestnut or chestnuts with the skin completely or incompletely removed may be immersed in an aqueous solution of hydrochloric acid. It is preferable to pre-cook with water for 2 to 5 minutes.

Next, an example of a chestnut peeling apparatus for carrying out the peeling method of the present invention will be described based on the accompanying drawings.

In the drawings, reference numeral 1 indicates a processing container made of a heat-resistant, power-transparent material, and the container 1 includes, for example, a cylindrical porous container 1a made of polypropylene resin with a heat-resistant temperature of 140° C. and a lid 5 fitted on its opening surface. 1b, the porous container 1a
A large number of through holes 2 are arranged at equal intervals on the peripheral wall of. In the container 1, a desired amount of chestnuts to be processed from which the skin has been incompletely removed is stored, and the chestnuts are added to the processing liquid WI.
Immerse in the desired amount of about 5% hydrochloric acid aqueous solution prepared in B for about 15 to 20 minutes.

In such a case, the chemical solution communicating through the large number of through holes 2 penetrates into the deep and astringent skins of the chestnuts in the processing container 1. In this case, the medicinal solution may be kept at room temperature, or heated to a low temperature of about 80° C. from room temperature. For example, use one heated to about 40°C.

In this way, the hydrochloric acid aqueous solution is used to weaken the binding force between the pulp surface and the astringent skin by dissolving pectin.

Next, the porous container 1 is pulled up from inside the processing liquid tank 3, and the second
The porous container 1 is immersed for several seconds in a tank 4 filled with a neutralizing agent solution C containing a neutralizing agent such as soda carbonate as shown in the figure to neutralize the hydrochloric acid adhering to the beams and bring the pH to 5 to 7. Take out, 3rd
The illustrated microwave irradiation device 5 is housed in a sealed processing chamber 6, and the center rods at both ends of the porous container 1 are connected to the processing chamber 6.
Fit and support the bearing support part provided on the opposite side wall of the
One end of the shaft is connected via a joint to a rotating device f7 consisting of an external manual handle or a rotating motor.

Thus, the microwave irradiation device 5 is activated and the processing chamber 6 is
The porous container 1 inside is rotated continuously or occasionally, and while the chestnuts inside are rolled, they are evenly irradiated with microwaves. As the microwave irradiation device 5, for example, a three-phase power supply^C200V, an output of 4.5Kw, 2450. MH2 air cooling is used, and the processing conditions are, for example, the processing amount of chestnuts in the container is 1
0 to 15 hg, processing amount 20 to 50 kg/hr, and one processing time 10 to 20 minutes.

The microwave irradiation is performed intermittently, for example, as shown in FIG. 4, and the initial irradiation amount is large and is gradually reduced and irradiated intermittently. As a guideline for heating by microwave irradiation, it is desirable to reduce the water content of chestnuts by about 7 to 15% by dehydration.

After being treated with the peeling device of the present invention as described above, take out the chestnuts from the porous container 1, hold the chestnuts through a thick cloth, and squeeze the chestnuts with your hands to easily remove the bitter skin and the astringent skin at once. Can be removed. The peeled chestnuts had good texture on the surface of the pulp, and the yield was ioo%.

Furthermore, the chestnuts pre-processed according to the present invention can be peeled easily and quickly by applying a light frictional force, and can be peeled by hand or by other means.
Existing skin removal machines, such as water jets, compressed air jets, and rotating friction using a soft stirring blade brush, can remove both skin and astringent skin at the same time. Chestnuts with only astringent skin from which the oniyu has been completely removed are even easier to peel.

The example shown in the fifth figure shows an example of peeling using rotational friction of a thin wire brush and water flow, in which the porous container 1 taken out from the processing chamber 6 of the microwave irradiation device 5 is immersed in water d in the peeling treatment tank 8. Then, remove the lid 1b, insert the rotary stirrer 1919 into the container 1 through the upper opening, rotate the rotary brush 9a of the stirrer 9, and use the rotational friction of the rotary brush 9a to remove the bitter skin and astringent skin of the chestnuts. I was able to peel it off at the same time.

The thermal atmosphere within the processing chamber 6 may be appropriately adjusted by providing an appropriate exhaust valve on the ceiling of the processing chamber 6 or the like. To perform continuous microwave irradiation treatment on chestnuts in a semi-closed environment, for example, a conveying screw is passed through a pipe with many small holes, and while the chestnuts are transferred by the rotation of the screw, the chestnuts are transported inside the porous pipe. can be transferred and microwaves can be passed through the pipe to irradiate and heat the moving chestnuts inside, while creating a steam atmosphere inside the pipe. Alternatively, a perforated belt conveyor such as a wire mesh may be passed through an acid aqueous solution tank, a neutralizer solution tank, a water tank, or the like to continuously treat each chestnut.

Next, the effects of the peeling treatment method according to the present invention will be shown through a comparative test.

Chestnuts with incompletely peeled skin were immersed in a 5% HCI aqueous solution at room temperature for 2 hours, and then microwave irradiation
1.2 per g in a W batch type microwave heating tank
．． When chestnuts obtained by the peeling method of the present invention that have been irradiated for 5 minutes (hereinafter referred to as real treated chestnuts A) are squeezed by hand through a thick cloth, the dark skin and the astringent skin can be peeled at the same time. ,
The peeling time was 3 minutes per 100 g of chestnuts. Moreover, peeled chestnuts have a thin layer of astringent skin on the surface of the pulp, so
It had a texture, and the pulp yield was 100%. or,
These peeled chestnuts were boiled in water, but the disintegration rate was 5%.

On the other hand, when peeling the outer skin and astringent skin of raw chestnuts with a knife, it took 18 minutes per 100g of chestnuts. Moreover, the yield was 52%. Furthermore, when the peeled chestnuts were boiled in water, the peeling rate was 30%.

Furthermore, for comparison, chestnuts obtained by immersion in a 15% hydrochloric acid aqueous solution for 2 hours at room temperature and neutralization treatment by immersion in a sodium bicarbonate aqueous solution for 15 seconds were peeled by hand squeezing. I tried, but couldn't peel it off.

In addition, during the above-mentioned treatment process of Kenpo, chestnuts obtained by adding a neutralization treatment process of immersing them in a 15% sodium bicarbonate aqueous solution for 15 seconds before the microwave heating treatment (hereinafter referred to as "naturally treated chestnuts B")
) was also manually peeled in the same way, but as with the original treated chestnuts A, the dark skin and astringent skin were easily peeled off, the skin peeling time was 3 minutes/100g, and the pulp yield was 100% (with texture). Met. In addition, the peeled chestnuts were boiled in water in the same way, and the cracking rate was only 5%.6 Next, the chestnuts peeled using a conventional knife and the chestnuts A and B treated with the peeling method according to the present method were temporarily frozen and stored. When I tasted the chestnuts that had been steamed to an edible state, I found that the chestnuts peeled with a conventional knife had a rather rough texture, but the chestnuts A and B peeled using this method did not have any rough texture at all, and they were especially chewy. The peeled chestnuts B obtained by this method were yellowish brown in color, had a sweet taste, had a sticky texture, and were delicious.

Next, the viscoelasticity of the edible chestnuts subjected to the natural peeling treatment B and the viscoelasticity of the conventional edible chestnuts peeled with a knife are shown in Table 2 below.

The measuring equipment is Neo Card Meter H = 302 (manufactured by Iio Electric), pressure sensitive shaft diameter 3 fl, 0.36 cm/Sf3C140.
0g load n=6°Next, more specific embodiments of the present invention will be described.

Example 1 2 kg of chestnuts whose skin had been mechanically incompletely removed were placed in the illustrated porous container 1, and immersed in a 2.5% hydrochloric acid aqueous solution bath at 50 to 60°C for 30 minutes. Next, the container 1 was immersed in a 15% sodium bicarbonate solution for 10 seconds to perform neutralization treatment, and the container 1 was placed in a sealed processing chamber of a microwave irradiation device with an output of 1.5 W, and was intermittently heated. was irradiated for a predetermined period of time. The irradiation time was 5 minutes. Also, as a guideline, the water content of raw chestnuts should be dehydrated by about 7 to 15%. Thereafter, the container was taken out of the processing chamber and placed into water.

After that, when the chestnuts were taken out of the container, the bitter skin and bitter skin could be easily removed at the same time by applying a 1/11 scale cloth-like cloth to the chestnuts and squeezing them with your hands. In addition, the astringent skin could be easily removed by blowing compressed air, rotating kneader using a soft rotating brush of an agitator, etc., and peeled chestnuts having the texture of the pulp were obtained with a yield of 100%.

Peeled chestnuts suitable as raw materials for processing marron glacé, chestnuts, etc. were obtained.

Example 2 The desired amount of incompletely peeled chestnuts as in Example was
After being immersed in a liquid bath consisting of a mixture of equal amounts of 0.8% hydrochloric acid aqueous solution and 0.8% sodium hexametaphosphate, microwave irradiation was performed in the same manner as in Example 1. Thereafter, this was squeezed by hand, and peeled chestnuts were easily obtained with a yield of 100%.

Due to the chelating effect of sodium hexametaphosphate, the surface of this fruit becomes less sticky and cannot be peeled off leaving clear texture on the surface.

Example 3 Chestnuts with their skins intact were immersed in a chemical solution made by adding 0.01% nonionic surfactant to a 10% aqueous hydrochloric acid solution,
It was soaked for 1.5 hours. At this time, the temperature of the chemical solution was adjusted to 50℃.
The immersion time may be shortened by heating to a certain degree. Thereafter, as in Example 1, neutralization treatment and heating by microwave irradiation were performed.

The above-mentioned nonionic surfactant has the effect of making it easier to penetrate the skin, making it easier to embed in the astringent skin, and making the skin extremely soft. After microwave irradiation, it is now possible to remove even the astringent skin using an existing skin peeling machine. In this way, the peeling process can be completed only once, and mechanical peeling can be performed with high efficiency.

In addition, manual peeling is easy; simply by cutting open one end of the skin with scissors, the peeled chestnuts can be taken out, resulting in a significant reduction in human labor.

Example 4 Chestnuts with the skin on are treated with an oxidizing agent, e.g. 0.1%.
After being immersed in a 10% aqueous solution of hydrochloric acid to which hydrogen peroxide had been added, the oxidation was accelerated by the microwave irradiation, causing the skin to become brittle and easily damaged.

Thus, chestnuts treated in this way can be washed with water, stirred, and the skin and astringent skin can be removed by manual or mechanical abrasion treatment.

〔Effect of the invention〕

According to the present invention, chestnuts with skin or chestnuts from which skin has been completely or incompletely removed are treated with a chemical solution and then subjected to microwave irradiation treatment.
It is obtained by releasing the bond between the pulp and the astringent skin, and the pulp is not split during peeling.
In particular, the astringent skin can be easily removed by simply squeezing it with your hands, and the yield during peeling is improved.
Furthermore, it has the effect of reducing the cracking of the meat during boiling.

In this way, by combining microwave irradiation treatment, a dilute aqueous acid solution with a chemical concentration of about 10% or less is sufficient, which maintains good quality of chestnut pulp and reduces the elution of components from the astringent skin of chestnuts. The more you can prevent wastewater pollution, the more you can prevent wastewater pollution.

Furthermore, as a chemical solution, an acid aqueous solution in which only an acid is dissolved in water, or a chelate solution containing an acid as a main ingredient, or a chelate solution as an additive.
When chestnuts are treated with an acid aqueous solution containing a surfactant, an oxidizing agent, or a mixture thereof, peeled chestnuts with no stickiness on the surface of the flesh can be obtained, and the acid solution can remove the skin from the chestnut skin and astringent skin. This facilitates the penetration and impregnation of the skin, softens the skin, makes it weaker due to oxidation, and has the effect of improving the peeling effect.

In addition, when neutralizing chestnuts that have been treated with a chemical solution consisting of an acid aqueous solution before or after microwave irradiation treatment, it is possible to obtain processing products with good texture and good viscoelasticity. ,
In addition, the sodium ions in the neutralizer can absorb microwaves, improve the heating temperature, and promote the separation effect between fruit pulp and astringent skin.

In addition, the microwave irradiation process uniformly heats the chestnut pulp from inside and dehydrates an appropriate amount of water content as steam, which makes the entire pulp firm and moderately softened, and can be used during or after peeling. This prevents the flesh from cracking and falling apart during the boiling and seasoning process. In this case, when performing the irradiation treatment continuously or intermittently, the irradiation amount is NI$
When irradiating in the manner described in step 4, it is possible to perform appropriate dehydration and heating without excessively softening the pulp, and it is also possible to soften the pulp to make it edible, and the subsequent boiling process can be shortened or omitted. It becomes possible.

In carrying out the chestnut peeling method of the present invention described above, if a porous container is used, this brings about the effect that the chemical solution immersion treatment and the neutralizing agent solution immersion treatment can be performed in each porous container.

Furthermore, when the chestnuts are irradiated with microwaves while being rolled, it is possible to uniformly heat the chestnuts.

Furthermore, when chestnuts are subjected to microwave irradiation in a sealed or semi-closed environment, the chestnuts can be heated in a warm atmosphere with water vapor emitted from the inside of the chestnut to the outside due to the irradiation heating, which softens the bitter skin and astringent skin. It also has the effect of facilitating the peeling process.

[Brief explanation of the drawing]

FIGS. 1 to 3 show an example of an apparatus for carrying out an example of the peeling treatment method of the present invention and its process diagram, FIG. 1 is a sectional view of the chemical solution immersion treatment apparatus, and FIG. , FIG. 3 is a sectional view of the microwave irradiation device, and FIG. 4 is a sectional view of the neutralizing agent liquid tank.
A graph of one example of the microwave irradiation conditions, FIG. 5, shows a sectional view of one example of the peeling treatment apparatus.

Claims (1)

[Claims] 1. A desired amount of chestnuts with the skin still attached or chestnuts with the skin completely or incompletely removed are treated with a chemical solution and then subjected to microwave irradiation treatment. Chestnut peeling method. 2. The method for peeling chestnuts according to claim 1, wherein after treating the chestnuts with an acid aqueous solution, the neutralization treatment is performed before or after the microwave irradiation treatment. 3.Claim 1 or 2, wherein the chemical solution is an acid alone or an acidic aqueous solution containing an acid as a main ingredient and adding and dissolving an additive in water.
Debarking method described. 4. The method for peeling chestnuts according to claim 1 or 2, wherein the chemical solution is an aqueous solution of about 0.5 to 10% hydrochloric acid. 5. The additive liquid according to claim 3 or 4, wherein the additive liquid is obtained by adding a chelating agent such as sodium hexametaphosphate, a surfactant, or an oxidizing agent, either singly or in a mixture thereof, to the acid aqueous solution. Chestnut peeling method. 6. The chestnut peeling method according to claim 1, wherein the microwave irradiation treatment is performed continuously or intermittently. 7. The method for peeling chestnuts according to claim 7, wherein the microwave irradiation is initially large and gradually reduced. 8. Chestnuts according to claim 1, 6 or 7, characterized in that a desired amount of chestnuts treated with a chemical solution are subjected to microwave irradiation treatment in a batch system or in an assembly line, while rolling them. Peeling treatment method. 9. Chestnuts according to claim 1, 6, 7 or 8, characterized in that when the chestnuts treated with a chemical solution are processed in a batch system or a flow system, the microwave irradiation treatment is performed in a closed or semi-closed environment. Peeling treatment method. 10. A microwave irradiation device equipped with a container provided with a large number of through holes, a processing chamber that houses the porous container in a sealed or semi-hermetically sealed manner, a motor and a handle that rotate the porous container accommodated in the processing chamber. Chestnut peeling processing equipment consisting of a rotating device such as. 11. The chestnut peeling apparatus according to claim 10, further comprising a neutralizing agent liquid tank.