JP6967685B1 - How to peel fruits - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly protect the surface of the outer pericarp of a fruit by unsaturated fatty acids such as linoleic acid and oleic acid, and waxy substance such as cuticle, and to use chemical treatment to protect the outer pericarp of the fruit. Alternatively, when removing the inner pericarp, it is necessary to perform a pretreatment such as a degreasing step on the fruit separately from the peeling treatment, and a simple method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp is required. As a result of diligent studies, the inventor has made a peeling treatment having a pH of 10 or more and 14 or less, which comprises sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride or potassium chloride, and a surfactant. By dissolving or peeling the outer or inner pericarp of the fruit using a liquid, the outer or citrus inner pericarp can be peeled off without a pretreatment step for removing unsaturated fatty acids and / or wax on the fruit surface. I found. [Selection diagram] Fig. 1

Description

The present invention relates to a method for peeling fruits.

Fruits are used in various foods such as raw foods, canned foods, bottled foods, and raw materials for the production of processed products such as frozen foods. Often. In the case of using the fruit as a flesh that maintains the shape of the fruit or producing a processed product, a method for efficiently and easily removing the inner pericarp of the outer pericarp of the fruit or citrus fruits is required.
In fruit processing, in order to obtain flesh, which is an edible part existing inside the outer pericarp or the inner pericarp, it is necessary to remove the outer pericarp of the fruit and the inner pericarp of citrus fruits as an inedible part.
In addition, the outer pericarp of the fruit has strong adhesion to the flesh, and it is not easy to remove the outer pericarp due to the various shapes of the fruit depending on the type and variety, the thickness of the outer skin, and the hardness of the flesh. It cannot be said that the supply is sufficient for the potential demand of.

Conventionally, as a method for removing the outer pericarp or the inner pericarp, a method of manually peeling off the outer pericarp or the inner pericarp with a finger for each grain or one by one has been used. For example, as a method for removing the outer pericarp of grapes, a food device (Patent Document 1) for rapidly peeling individual grape skins is used, and the outer pericarp is manually removed for each grain by hand. How to do it is known. However, the measures that rely on manpower are limited to small-quantity production with limited varieties due to their low productivity, and are only valid for those that can obtain high added value. In addition, the method of removing the outer pericarp of the fruit with an instrument inevitably removes a part of the flesh together with the outer pericarp. Therefore, the original form of the flesh could not be maintained, and in addition to deteriorating the yield of the flesh, a large amount of residue was removed, and the cost of disposal of the residue was high.

The following methods are known as methods for physically removing the outer or inner pericarp of fruits. For example, as a method of efficiently peeling grape fruits, a method of combining a mobile roller and a water stream (Patent Document 2), a pair of grapes on a pair of rolls while being fed by a spiral ridge of the rolls. A device (Patent Document 3) is known in which the skin is pressed between the rolls, the skin is sandwiched between the rolls, and the skin is peeled off. However, the method of removing the outer or inner pericarp of a fruit by a rational method using a roller or water pressure is a dedicated machine for the target fruit and lacks versatility, and in addition, it is a large machine or device. There was a drawback that it was necessary to introduce it and the maintenance cost was high. In addition, it is not suitable for practical use due to uneven peeling treatment and the risk of line retention due to equipment malfunction.

In addition to the above methods, the following methods are known as methods for removing the outer pericarp or the inner pericarp of fruits by using a chemical treatment. The chemical treatment method is excellent in that it can easily remove the outer pericarp and / or the inner pericarp of the fruit by immersing it in a chemical solution, the introduction cost is low in terms of equipment, and it can handle a wide variety of fruits and citrus fruits. There is. Further, since only the pericarp is removed by a chemical agent, it is excellent in that damage to the flesh portion, which is an edible portion, can be suppressed.

Conventionally used chemical treatment methods include, for example, a peeling method for softening and disintegrating fruit skin by treating the fruit surface with a peeling agent consisting of alkalis and alcohols (Patent Document 3), and peeling of fruits. A method of using an alkaline aqueous solution as a dipping solution and adding a fatty acid to the solution (Patent Document 4), a method of peeling grapes in which a surfactant treatment and an alkaline treatment are independently and continuously performed (Patent Document 5), and a laceration expansion treatment. A method of immersing grape fruits in an enzyme-containing solution and peeling the pericarp from the fruit flesh is known (Patent Document 6).

Japanese Unexamined Patent Publication No. 2010-142618 Japanese Unexamined Patent Publication No. 02-207779 Japanese Unexamined Patent Publication No. 53-08834 Japanese Unexamined Patent Publication No. 54-151153 Japanese Unexamined Patent Publication No. 2016-185135 Japanese Patent Laid-Open No. 2021-003065

However, the surface of the outer pericarp of the fruit is strongly protected by unsaturated fatty acids such as linoleic acid and oleic acid, and waxy substances such as cuticle, and the outer pericarp of the fruit or the outer pericarp of the fruit is chemically treated. In the case of removing the inner pericarp, even if the chemical treatment was directly applied to the outer pericarp surface, the chemical solution did not get wet and a sufficient peeling effect could not be obtained.
Therefore, when removing the outer or inner pericarp of a fruit by using a chemical treatment, it is necessary to perform a pretreatment such as a degreasing step on the fruit separately from the peeling treatment, and a simple fruit peeling method is available. It has been demanded.

In the multi-step treatment, the treatment process becomes complicated and the amount of the drug used increases.
Therefore, there is a demand for a simpler fruit peeling method that uses less chemicals and does not require waste or waste liquid treatment costs.

As a result of diligent studies, the inventor used a peeling treatment solution having a pH of 10 or more and 14 or less containing sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride, and a surfactant to remove the fruit. It has been found that by dissolving or peeling the pericarp, the outer pericarp of the fruit or the inner pericarp of citrus fruits can be peeled off without a pretreatment step for removing the unsaturated fatty acid and / or the waxy substance present on the surface of the outer pericarp of the fruit.
The present invention will be specifically described below.

[1] The outer or inner flesh of the fruit using a peeling solution containing sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride or potassium chloride, and a surfactant and having a pH of 10 or more and 14 or less. It is characterized by comprising a first step of dissolving or peeling the flesh to obtain the flesh, and a second step of immersing the flesh in an acidic aqueous solution containing an organic acid and having a pH of 2 or more and 6 or less to neutralize the peeling treatment liquid. How to peel the fruit.

[2] The concentration of sodium hydroxide or potassium hydroxide in the peeling treatment liquid is 0.5% by weight or more and 10% by weight or less, and the sodium hypochlorite concentration is 0.1% by weight or more and 5% by weight or less. The fruit according to [1], wherein the sodium chloride concentration is 0.01% by weight or more and 5% by weight or less, and the surfactant concentration is 0.01% by weight or more and 5% by weight or less. Peeling method.

[3] The first step is a treatment of immersing the fruit in a peeling treatment solution having a temperature of 30 ° C. or higher and 95 ° C. or lower for a time of 10 seconds or longer and 600 seconds or lower. Peeling method.

[4] The method for peeling fruits according to any one of [1] to [3], wherein the surfactant is a sucrose fatty acid ester.

[5] The method for peeling a fruit according to any one of [1] to [4], wherein the fruit is a grape fruit, an apple fruit, or a citrus fruit.

By using the method for removing peeling of fruit outer pericarp or citrus inner pericarp according to the present invention, the fruit outer pericarp / inner is without a pretreatment step for removing unsaturated fatty acids and / or waxy substances present on the fruit outer pericarp surface. Only the pericarp can be dissolved or peeled by the drug. Therefore, the amount of waste residue and waste liquid can be minimized. In addition, since it is only necessary to heat the peeling treatment liquid for energy consumption, the environmental load can be minimized.

According to the method for removing peeling of fruit outer pericarp or citrus inner pericarp according to the present invention, there are restrictions on the maturity, morphology and size of the fruit to be processed, the thickness and thinness of the outer and inner pericarp, the hardness and softness of the flesh, and the color of the outer pericarp. However, it can be applied to many fruit varieties for processing purposes.

It is a process schematic diagram of a dipping method. It is a process schematic diagram of a continuous method. It is a contrast diagram before and after removal of the outer pericarp of Shine Muscat fruit. It is a contrast diagram before and after the removal of the outer pericarp of an apple fruit. It is a peeled apple outer pericarp. It is a contrast chart before and after the removal of the outer pericarp of Amanatsu citrus fruit.

Hereinafter, a preferred embodiment of the method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp according to the present invention will be described in detail.

<Feeling removal method>
The method for removing the peeling of the fruit outer pericarp or the citrus inner peel according to the present invention is a peeling having a pH of 10 or more and 14 or less, which comprises sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride, and a surfactant. The first step (FIG. 1 (A)) of dissolving or peeling the outer or inner pericarp of the fruit using the treatment liquid, and dissolving or peeling the outer or inner pericarp in an acidic aqueous solution containing an organic acid and having a pH of 2 or more and 6 or less. It is characterized by comprising a second step of immersing the soaked fruit (FIG. 1 (B)).

As the method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp according to the present invention, for example, a method of dipping by a batch method using a row or a tray can be adopted, or a method of continuous immersion using a shower or a spraying device or the like can be adopted. It is also possible to adopt a method of processing the citrus. As a reference, FIGS. 1 and 2 illustrate a schematic process diagram by a batch method or a continuous method.

FIG. 1 is a schematic diagram of a process in which the peeling of the fruit outer pericarp or the citrus inner pericarp according to the present invention is performed by a batch method using a row or a tray.
After the fruit 1 to be peeled is put into the net cage 12, the net cage 12 is immersed in a treatment tank 11 containing the peeling treatment liquid 3 heated by the heater 13, and the peel is removed to obtain the pulp 2. (FIG. 1 (A)). Then, the net cage 12 containing the pulp 2 is immersed in the neutralization tank 14 containing the acidic aqueous solution 4 (FIG. 1 (B)). After that, the fruit flesh 2 contained in the net cage 12 is washed with water (FIG. 1 (C)), whereby the fruit peeling treatment can be performed by a batch method.

FIG. 2 is a schematic process diagram in the case where the peeling of the fruit outer pericarp or the citrus inner pericarp according to the present invention is continuously treated using a shower, a spraying device, or the like.
The fruit 1 to be peeled is conveyed using the conveyor 21, the heated peeling treatment liquid 3 is ejected from the nozzle 24 via the liquid transport pump 23, and the conveyed fruit 1 is peeled. After that, the acidic aqueous solution 4 is continuously ejected through another liquid transport pump 23 and the nozzle 24 to neutralize the conveyed pulp 22. This allows the fruit to be continuously peeled. The excess peeling treatment liquid 3 or the acidic aqueous solution 4 ejected from the nozzle can be recovered by using the tray 22 provided at the bottom of the conveyor.

The peeling treatment liquid 3 used in the first step is an alkaline aqueous solution composed of at least a main agent, an additive, and a solvent. The main agent of the peeling treatment liquid can be composed of at least a strong base and sodium hypochlorite (NaClO). Additives can be added to the peeling treatment liquid as long as the effects of the invention are not impaired. The additive can be composed of at least sodium chloride or potassium chloride, and a surfactant. The solvent is mainly composed of water.

The acidic aqueous solution 4 used in the second step is composed of an aqueous solution containing at least an organic acid, and after treating the fruit in the first step, neutralizes the peeling treatment liquid that adheres to the flesh 2 and impregnates the flesh 2. Used for purposes. A running water washing step can be added between the first step and the second step. The running water washing step is effective for efficiently removing the residue such as the peeling treatment liquid and the outer pericarp of the fruit adhering to the surface of the fruit flesh 2 and extending the life of the neutralizing liquid.

<Fruits and citrus fruits>
By using the method for removing peeling of fruit outer pericarp or citrus inner pericarp according to the present invention, the fruit outer pericarp / inner is without a pretreatment step for removing unsaturated fatty acids and / or waxy substances present on the fruit outer pericarp surface. Only the pericarp can be dissolved or peeled by the drug.
Here, the outer pericarp of the fruit means the outermost layer of the fruit skin. For example, it refers to the pericarp that is red for apples, orange for oranges, purple for grapes, and green for Muscat.
The inner pericarp of a fruit is the innermost layer of the pericarp. The inner pericarp of citrus fruits in the present invention refers to a portion of white skin called albedo existing inside the outer pericarp of citrus fruits, but may include a vascular bundle and a cystic membrane portion in addition to the albedo portion.

Fruits that can use the method for removing peeling of fruit outer pericarp or citrus inner pericarp according to the present invention have unsaturated fatty acids such as linoleic acid and oleic acid, oils and fats, or cuticles on the surface of the outer pericarp of the fruit. The fruit is not particularly limited as long as it is a fruit having a waxy substance such as, and can be applied to various fruits.

Examples of the fruit for which the method for removing the peeling of the fruit outer peel or the citrus inner peel according to the present invention can be used include sweet summer citrus, orange, tangerine, summer tangerine, iyokan, grapefruit, kinkan, sudachi, lemon, and bergamot. Citrus fruits such as Zabon, Daidai, Hinata Natsu, peaches, apples, white grapes, pears, pears, apricots, peaches, cherries, sea urchins, prunes, biwa, karin and other fruits of the rose family, deraware, giant peaks, pione, muscat Grape such as of Alexandria, Shine Muscat, Neo Muscat, Delaware, Glow Coleman, figs, persimmons, mangoes, cassis, kiwi, acerola, blueberries, etc. , Two or more of these fruits may be used in combination.
Among them, one or more fruits selected from sweet summer citrus, orange, tangerine, peach, apple, pear, delaware, Kyoho, pione, muscat of Alexandria, Shine Muscat, neo muscat are preferable, and sweet summer citrus, More preferably, one or more fruits selected from apples, delaware, Kyoho, pione, muscat of Alexandria, Shine Muscat.

Hereinafter, the method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp of the present invention will be described in detail for each step.

<First step>
The method for removing the peeling of the outer pericarp or the inner pericarp of citrus fruits of the present invention contains sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride or potassium chloride, and a surfactant, and has a pH of 10 or more and 14 or less. This is a method of dissolving or peeling the outer or inner pericarp of a fruit using the peeling treatment solution 3 of the above (see FIG. 1 (A)).

In the first step according to the present invention, for example, a method of dipping treatment by a batch method using a row or a tray can be adopted (see FIG. 1), or continuous treatment is performed using a shower or a spraying device. It is also possible to adopt the method of (see FIG. 2).

In the first step of peeling and removing the outer pericarp of the fruit or the inner pericarp of citrus fruits using the peeling treatment liquid 3, the peeling treatment liquid 3 can be heated and used as long as the effect of the present invention is not impaired. By heating the peeling treatment liquid 3, the reaction rate between the treatment liquid and the pericarp can be increased, so that the peeling treatment time can be shortened. By shortening the peeling treatment time, it is possible to improve the efficiency of the peeling work and the time efficiency, and it is possible to prevent excessive impregnation of the peeling treatment liquid 3 into the flesh portion. However, if the temperature of the peeling treatment liquid 3 is too high, the flavor and taste of the fruit will be deteriorated, which is not preferable.
Therefore, the temperature of the peeling treatment liquid 3 in the first step is preferably in the range of 40 ° C. or higher and 97 ° C. or lower, and more preferably in the range of 80 ° C. or higher and 90 ° C. or lower.

In the first step of peeling and removing the fruit outer pericarp or the citrus inner pericarp using the peeling treatment liquid 3, the treatment time with the peeling treatment liquid 3 can be appropriately adjusted as long as the effect of the present invention is not impaired. The treatment time varies depending on the type of fruit, the thickness of the outer or inner pericarp to be peeled off, and the degree of adhesion to the flesh 2, but if the treatment time is excessively long, the peeling work becomes more efficient and time efficient. Not preferable from the viewpoint of improvement. On the other hand, when the treatment time is excessively short, variations in the treatment are likely to occur, and it is necessary to use a more reactive peeling treatment liquid, which is not preferable.
Therefore, the processing time is preferably 10 seconds or more and 600 seconds or less, more preferably 10 seconds or more and 300 seconds or less, and further preferably 30 seconds or more and 180 seconds or less.

(Peeling treatment liquid: main agent)
The peeling treatment liquid 3 used in the method for removing the peeling of the fruit outer pericarp or the citrus inner peel of the present invention will be described. The peeling treatment liquid 3 used in the first step is an alkaline aqueous solution composed of at least a main agent, an additive, and water as a solvent.
The main agent of the peeling treatment liquid 3 is composed of at least a strong base and sodium hypochlorite (NaClO).

The strong base component that can be used as the main agent of the peeling treatment liquid 3 according to the present invention is particularly limited as long as it is a compound that can be used as a food additive and can raise the pH of the treatment liquid to 10 or more. Although it is not used, it is industrially produced as a food additive and is a drug that is easy to obtain, store, and handle. Sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca) (OH) 2) can be preferably used.
The pH of the solution can be easily measured by using a commercially available pH measuring device, but a pH test paper or the like can also be used.

The surface of the outer pericarp of the fruit is strongly protected by unsaturated fatty acids such as linoleic acid and oleic acid, and waxy substances such as cuticle, and if these oils and fats are not removed, the outer pericarp is peeled off. That is difficult.
Hydroxide ions generated from sodium hydroxide and the like can be decomposed into fatty acid salts and glycerol by saponifying with unsaturated fatty acids and / or waxes present on the surface of fruits. By this reaction, unsaturated fatty acids and / or waxes present on the fruit surface can be dissolved or dispersed in the peeling treatment liquid.

This reaction rate increases as the temperature of the peeling treatment liquid 3 rises. Therefore, as described above, in the step of peeling and removing the fruit outer pericarp or the citrus inner pericarp using the peeling treatment liquid 3, it is preferable to appropriately heat the peeling treatment liquid 3 as long as the effect of the present invention is not impaired. By heating the peeling treatment liquid 3, the peeling treatment time can be shortened.

As the strong base component that can be used as the main agent of the peeling treatment liquid 3 according to the present invention, sodium hydroxide, potassium hydroxide and calcium hydroxide can be preferably used, but potassium hydroxide (pKa: 14) is used. Since the dissociation constant is higher than that of sodium hydroxide (pKa: 13) and calcium hydroxide (pKa: 12.7), it can be suitably used when it is necessary to perform the peeling treatment at a higher pH.
Further, potassium hydroxide has a high possibility of maintaining a liquid state as compared with sodium hydroxide and calcium hydroxide even when a saponification reaction is carried out with unsaturated fatty acids and / or waxes. Therefore, it can be suitably used when a solid substance is produced when sodium hydroxide is used.

The concentration of the strong base component that can be used as the main agent of the peeling treatment liquid 3 according to the present invention is not particularly limited as long as it does not impair the effect of the present invention, but is 0.5% by mass or more. The range of mass% or less is preferable, the range of 1.0 mass% or more and 5 mass% or less is more preferable, and the range of 1.5 mass% or more and 2.5 mass% or less is more preferable.

Sodium hypochlorite (NaClO) is used as the main agent of the peeling treatment liquid 3 according to the present invention in addition to the strong base component. The hypochlorite ion generated from sodium hypochlorite has an oxidative decomposition action of an organic substance and an adsorption substitution action at a solid-liquid interface. Therefore, by adding hypochlorite ion to the peeling treatment liquid 3, the wettability of the fruit of the peeling treatment liquid 3 to the outer pericarp or the inner pericarp can be dramatically improved. As a result, a sufficient peeling effect can be obtained, and pretreatment such as a degreasing step, which has been conventionally required, can be omitted.
In addition, sodium hypochlorite is an unstable substance that decomposes into chloride and oxygen due to sunlight or the like, but by coexisting with a strong base component such as sodium hydroxide, the storage stability of the peeling treatment liquid 3 is also improved. Can be improved.

The concentration of the sodium hypochlorite component that can be used as the main agent of the peeling treatment liquid 3 according to the present invention is not particularly limited as long as it does not impair the effect of the present invention, but is 0.01 mass by mass. The range of% or more and 5% by mass or less is preferable, the range of 0.1% by mass or more and 3% by mass or less is more preferable, and the range of 1% by mass or more and 3% by mass or less is more preferable.

The concentration ratio of the strong base and sodium hypochlorite is the variety of the fruit to be processed or the citrus grains separated from the bunch, the maturity, the thickness of the outer pericarp / inner pericarp, the size of the fruit / pericarp, and the outer pericarp. It can be appropriately changed depending on the dye (green, red, black) and the like as long as the effect of the present invention is not impaired.

(Peeling treatment liquid: additive)
The additive contained in the peeling treatment liquid 3 used in the method for removing the peeling of the fruit outer pericarp or the citrus inner peel of the present invention will be described. The peeling treatment liquid 3 used in the first step is composed of at least a main agent, an additive, and water as a solvent, and the additive is at least a surfactant and sodium chloride or potassium chloride. Consists of.

As a component of the surfactant that can be used as an additive for the peeling treatment liquid 3 according to the present invention, a sucrose fatty acid ester can be preferably used. The sucrose fatty acid ester can be stably present in acidic and alkaline aqueous solutions, and can also be stably present in an oxidizing agent. It is also excellent in that it is not easily affected by the hardness of water and has defoaming properties. In addition, sucrose fatty acid ester is also commonly used as a food additive, and is also characterized by its high safety to the human body.

The type of sucrose acid ester is not particularly limited as long as the object of the present invention is not impaired, but the fatty acid species in the sucrose fatty acid ester have high hydrophilicity and heat resistance. Those containing a molecular structure derived from lauric acid (C12), myristic acid (C14), palmitic acid (C16), stearic acid (C18), and oleic acid (C18), which are compatible with strong bases, are more preferable.
The fatty acid that is the raw material of the sucrose fatty acid ester may be one kind or a combination of two or more kinds, and a plurality of ester bonds may be present in the sucrose fatty acid ester.

The concentration of the sucrose ester that can be used as an additive for the peeling treatment liquid 3 according to the present invention is not particularly limited as long as it does not impair the effects of the present invention, but is 0.01% by mass. The range of 5% by mass or less is preferable, the range of 0.01% by mass or more and 1% by mass or less is more preferable, and the range of 0.01% by mass or more and 0.5% by mass or less is more preferable.

The peeling treatment liquid 3 used in the method for removing peeling of the fruit outer pericarp or the citrus inner peel of the present invention contains sodium chloride or potassium chloride as an additive. These sodium chloride or potassium chloride are used to increase the polarity of the peeling treatment liquid 3. Sodium chloride can be preferably used when the main agent of the peeling treatment liquid 3 contains sodium hydroxide, and potassium chloride is preferably used when the main agent of the peeling treatment liquid 3 contains potassium hydroxide. Can be used for.
As these additives, only one kind of compound may be used, or two kinds may be mixed and used.

For example, when sodium hydroxide is used as the alkaline component of the main agent, it is preferable to use sodium chloride and sodium hydroxide at the same molar concentration. When potassium hydroxide is used as the alkaline component of the main agent, it is preferable to use potassium chloride at the same molar concentration as potassium hydroxide.
By adding a salt such as sodium chloride, the polarity of the peeling treatment liquid 3 can be increased and the interfacial tension of the fat and oil can be lowered, so that the speed at which the fat and oil is detached from the surface of the peel can be accelerated. Be expected.

The concentration of sodium chloride or potassium chloride that can be used as an additive for the peeling treatment liquid 3 according to the present invention is not particularly limited as long as it does not impair the effects of the present invention, but is 0.01 mass by mass. The range of% or more and 5% by mass or less is preferable, the range of 0.01% by mass or more and 1% by mass or less is more preferable, and the range of 0.01% by mass or more and 0.5% by mass or less is more preferable.

Further, a pH buffer solution or a pH buffering agent can be used as an additive in the peeling treatment liquid 3 used in the method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp of the present invention. By using a pH buffer solution or a buffering agent, the pH of the peeling treatment solution 3 can be easily adjusted, and the life of the solution can be extended.
The pH buffer solution or pH buffering agent that can be used for the peeling treatment liquid 3 according to the present invention is not particularly limited as long as the pH of the peeling treatment liquid 3 can be maintained in the range of 10 or more and 14 or less. For example, a basic hydroxy acid salt or a basic carboxylate salt can be preferably used. Specifically, Na lactate salt, K lactate K salt, Ca lactate salt, Na malic acid salt, Na citric acid salt, K citric acid salt, and Ca citric acid salt can be used as the basic hydroxyate salt. As the basic carboxylate, Na acetate salt and Ca acetate salt can be used.

<Second step>
In the second step of the method for removing the peeling of the fruit outer pericarp or the citrus inner peel of the present invention, the fruit in which the outer pericarp or the inner pericarp is dissolved or peeled is immersed in an acidic aqueous solution 4 containing an organic acid and having a pH of 2 or more and 6 or less, and the peeling is performed. The treatment liquid 3 is neutralized (see FIG. 1 (B)).

The acidic aqueous solution 4 used in the second step is composed of an aqueous solution containing at least an organic acid, and after treating the fruit in the first step, neutralizes the peeling treatment liquid 3 that adheres to the flesh 2 and impregnates the flesh 2. It is used for the purpose of removing it. By this step, the pH of the flesh 2 is lowered to close to the pH of the original raw fruit, and the acidity is adjusted. After appropriately adjusting the acidity, the excess neutralizing solution adhering to the flesh 2 can be removed to obtain the flesh 2 from which the outer or inner pericarp has been peeled off (see FIG. 1 (C)). The pH of the solution can be easily measured by using a commercially available pH measuring device, but a pH test paper or the like can also be used.

In the second step according to the present invention, for example, a method of dipping treatment by a batch method using a row or a tray can be adopted (see FIG. 1), or continuous treatment is performed using a shower or a spraying device. (See FIG. 2) can also be adopted.

The acidic aqueous solution 4 used in the second step can be used at room temperature or can be heated before use. For example, by heating the acidic aqueous solution 4, the neutralization rate of the peeling treatment liquid 3 can be increased, so that the neutralization treatment time can be shortened. By shortening the neutralization treatment time, it is possible to improve the efficiency of the peeling work and the time efficiency. However, if the temperature of the acidic aqueous solution 4 is too high, the flavor and taste of the fruit will be deteriorated, which is not preferable.

The processing time of the second step can be appropriately adjusted as long as the effect of the present invention is not impaired. The treatment time varies depending on the type of fruit, the thickness of the outer or inner pericarp to be removed, and the degree of adhesion to the flesh 2, but the end point is when the pH of the flesh 2 becomes close to the pH of the original raw fruit. Can be. If the treatment time is excessively long, the treatment liquid impregnates the inside of the flesh 2 and the flesh 2 becomes acidic. As a result, the flesh 2 becomes sour and the flavor and taste of the fruit deteriorates, which is not preferable.

(Neutralizer)
The composition of the acidic aqueous solution 4 used in the method for removing the peeling of the fruit outer pericarp or the citrus inner pericarp of the present invention will be described. The acidic aqueous solution 4 used in the second step is an acidic aqueous solution containing at least an organic acid.
The organic acid that can be used as a neutralizing agent is not particularly limited as long as it can be used as a food additive and the pH of the treatment liquid can be 6 or less. For example, as the organic acid that can be used as a neutralizing agent, acetic acid, citric acid, tartrate acid, sorbic acid, nicotinic acid, fumaric acid, propionic acid, lactic acid, malic acid, hydrochloric acid, and sulfuric acid are preferably used, and food addition is preferable. It is more preferable to use acetic acid, citric acid, hydrochloric acid, and sulfuric acid, which are industrially produced as products and are easy to obtain, store, and handle.

Hereinafter, the present invention will be specifically described with reference to Examples. Here, "%" is a "mass percent concentration" unless otherwise specified.

(Example 1)
<First step>
(Adjustment of peeling treatment liquid)
20 g of food additive grade sodium hydroxide (manufactured by Takasugi Pharmaceutical Co., Ltd.) and 167 g of food additive grade 12% sodium hypochlorite aqueous solution (manufactured by Takasugi Pharmaceutical Co., Ltd.) are mixed to prepare the main ingredient of the peeling treatment liquid. bottom.
0.2 g of a food additive grade sucrose fatty acid ester (manufactured by Mitsubishi Chemical Corporation) and 1 g of sodium chloride were added to the main agent, and then water was added to prepare 1 L of a peeling treatment solution.

(Peeling treatment)
In this example, the peeling of the outer pericarp of grape fruit (Shine Muscat) was removed.
After filling the dipping tank with 1 L of the adjusted peeling treatment liquid, it was heated by an electric heater so that the liquid temperature became 90 ° C. Four Shine Muscat grains (FIG. 3 (A)) removed from the bunch were immersed in the heat-peeling treatment liquid, and the outer pericarp of Shine Muscat was peeled off. Immediately thereafter, Shine Muscat was washed with running water to wash off the peeling residue and the outer pericarp residue adhering to the surface of the fruit grains.

<Second step>
(Neutralization treatment)
Shine Muscat washed with running water was immersed in a citric acid (food additive grade) aqueous solution having a pH adjusted to 5. The unwashed peeling solution and the base permeated into the pulp were neutralized, and the pH was lowered to near the pH of the original raw material Shine Muscat. Shine Muscat pulp from which the outer pericarp of the fruit was removed was obtained (FIG. 3 (B)).

(Example 2)
<First step>
(Adjustment of peeling treatment liquid)
The peeling treatment liquid was adjusted in the same manner as in the method described in Example 1.

(Peeling treatment)
In this example, the peeling of the outer pericarp of apple fruit was removed.
After filling the immersion tank with 1 L of the adjusted peeling treatment liquid 3, the liquid was heated with an electric heater so that the liquid temperature became 90 ° C. One apple fruit (FIG. 4 (A)) was immersed in the heated peeling treatment solution for 120 seconds to peel off and remove the outer pericarp of the apple fruit (FIG. 4). Immediately thereafter, the apple fruits were washed with running water to wash off the peeling residue and the outer pericarp residue adhering to the surface of the fruit grains.
The outer pericarp of the peeled apple fruit is shown in FIG.

<Second step>
(Neutralization treatment)
Apple fruits washed with running water were immersed in an aqueous solution of citric acid (food additive grade) having a pH adjusted to 5. The unwashed peeling solution and the base permeated into the flesh were neutralized, and the pH was lowered to near the pH of the original raw apple fruit. Apple pulp from which the outer pericarp of the fruit had been removed was obtained (FIG. 4 (B)).

(Example 3)
<First step>
(Adjustment of peeling treatment liquid)
The peeling treatment liquid was adjusted in the same manner as in the method described in Example 1.

(Peeling treatment)
In this example, the inner pericarp of Amanatsu citrus fruit was removed. The outer pericarp of Amanatsu citrus fruits was manually removed, and the tufts were manually separated (FIG. 6 (A)).
After filling the dipping tank with 1 L of the adjusted peeling treatment liquid, it was heated by an electric heater so that the liquid temperature became 90 ° C. The outer pericarp was removed from the heated peeling treatment solution, and one Amanatsu citrus fruit that had been bunched was immersed for 40 seconds to dissolve or peel the inner pericarp of the Amanatsu citrus fruit. Immediately after that, the Amanatsu citrus fruits were washed with running water to wash off the peeling residue and the outer pericarp residue adhering to the surface of the fruit grains.

<Second step>
(Neutralization treatment)
Amanatsu citrus fruits washed with running water were immersed in a citric acid (food additive grade) aqueous solution having a pH adjusted to 5. The unwashed peeling solution and the base permeated into the flesh were neutralized, and the pH was lowered to near the pH of the original raw material, Amanatsu citrus fruit. Amanatsu flesh from which the outer pericarp of the fruit was removed was obtained (FIG. 6 (B)).

(Example 4)
<First step>
(Adjustment of peeling treatment liquid)
20 g of food additive grade sodium hydroxide and 8.4 g of a food additive grade 12% sodium hypochlorite aqueous solution were mixed to prepare a main ingredient of a peeling treatment solution.
0.2 g of a food additive grade sucrose fatty acid ester and 1 g of sodium chloride were added to the main agent, and then water was added to prepare 1 L of a peeling treatment liquid.

The peeling treatment was carried out in the same manner as in the method described in Example 1.
The neutralization treatment was carried out in the same manner as in the method described in Example 1. Shine Muscat pulp from which the outer pericarp of the fruit was removed was obtained.

(Example 5)
<First step>
(Adjustment of peeling treatment liquid)
20 g of food additive grade sodium hydroxide and 417.5 g of a food additive grade 12% sodium hypochlorite aqueous solution were mixed to prepare a main agent for a peeling treatment solution.
0.2 g of a food additive grade sucrose fatty acid ester and 1 g of sodium chloride were added to the main agent, and then water was added to prepare 1 L of a peeling treatment liquid.

The peeling treatment was carried out in the same manner as in the method described in Example 1.
The neutralization treatment was carried out in the same manner as in the method described in Example 1. Shine Muscat pulp from which the outer pericarp of the fruit was removed was obtained.

(Example 6)
The peeling treatment liquid was adjusted in the same manner as in the method described in Example 1.
The peeling treatment was carried out in the same manner as in Example 1 except that the temperature of the peeling treatment liquid was changed to 60 ° C.
The neutralization treatment was carried out in the same manner as in the method described in Example 1. Shine Muscat pulp from which the outer pericarp of the fruit was removed was obtained.

(Example 7)
The peeling treatment liquid was adjusted in the same manner as in the method described in Example 1.
The peeling treatment was carried out in the same manner as in Example 1 except that the temperature of the peeling treatment liquid was changed to 40 ° C.
The neutralization treatment was carried out in the same manner as in the method described in Example 1. Shine Muscat pulp from which the outer pericarp of the fruit was removed was obtained.

(Comparative Example 1)
<First step>
(Adjustment of peeling treatment liquid)
20 g of food additive grade sodium hydroxide was used as the main ingredient of the peeling treatment liquid. 0.2 g of a food additive grade sucrose fatty acid ester and 1 g of sodium chloride were added to the main agent, and then water was added to prepare 1 L of a peeling treatment liquid.

The peeling treatment was carried out in the same manner as in the method described in Example 1.
The neutralization treatment was carried out in the same manner as in the method described in Example 1.

(Comparative Example 2)
<First step>
(Adjustment of peeling treatment liquid)
20 g of food additive grade sodium hydroxide and 167 g of a food additive grade 12% sodium hypochlorite aqueous solution were mixed to prepare a main ingredient of a peeling treatment solution.
After adding 1 g of sodium chloride to the main agent, 1 L of the peeling treatment liquid was prepared by adding water.

The peeling treatment was carried out in the same manner as in the method described in Example 1.
The neutralization treatment was carried out in the same manner as in the method described in Example 1.

(Comparative Example 3)
The peeling treatment liquid was adjusted in the same manner as in the method described in Example 1.
The peeling treatment was carried out in the same manner as in Example 1 except that the temperature of the peeling treatment liquid was changed to 30 ° C.
The neutralization treatment was carried out in the same manner as in the method described in Example 1.

The test conditions and their results described in Examples and Comparative Examples are summarized in Table 1.
The peeling performance in the evaluation column indicates whether or not the outer or inner pericarp of the fruit could be peeled by the treatment of the first step for the fruit obtained by the dipping treatment in the first step described in each Example or Comparative Example. The evaluation result is shown. The evaluation criteria are as follows.
◎: The outer or inner pericarp of the fruit could be removed 〇: The outer or inner pericarp of the fruit could be removed by applying a slight force such as stirring △: The outer or inner pericarp of the fruit without using hands or chopsticks The pericarp could not be removed ×: The outer or inner pericarp of the fruit could not be removed

The uniformity of the treatment in the evaluation column was visually evaluated as to whether or not the flesh obtained after the neutralization treatment in the second step could be treated uniformly without any peel residue, discoloration or unevenness. The evaluation criteria are as follows.
⊚: No “pericarp residue”, “discoloration” or “unevenness” was observed in the flesh.
〇: One of "pericarp residue", "discoloration", and "unevenness" was observed in the flesh.
Δ: Any two of “pericarp residue”, “discoloration”, and “unevenness” were observed in the flesh.
X: “Peel residue”, “discoloration”, and “unevenness” were all observed in the flesh.

Grape pulp is in great demand due to its excellent taste as a taste, but due to the difficulty of processing, the processing cost (peeling cost) is higher than the raw material cost, and both the unit price and quantity are restricted. If these are resolved and the production quantity and economic unit price / quality are secured, there is potential expected from various processing industries such as jams, fruit sauces, sweets, jelly products, dried products, and frozen products as raw materials for secondary processing. It can be said that the scale of demand is very large.
In general, unprocessed grape pulp also has a strong palatability, and it also provides demand as a fruit mix mixed with other fruits from a single meal like oranges and peaches in the form of the pulp. It is highly expected from the variety of products and economic efficiency.

Currently, the unit price and quantity of citrus fruits are secured in Wenzhou oranges, but the supply and demand of oranges, grapefruits, navel oranges, and sweet summers is not as high as that of Wenzhou oranges. This is due to the unsatisfied technique for removing the inner pericarp of each variety. If this is resolved, it will be possible to select a wide variety of varieties, secure a supply amount that meets demand, and supply citrus pulp that meets consumption needs in the same way as grapes. Not only the varieties mentioned above but also other citrus fruits can be supplied by diversion of this technology.
In addition, the current acid / alkali treatment takes nearly two hours for peeling, the equipment is long, the amount of chemicals used is large, and the wastewater treatment equipment and costs are very high. With the technology of the present invention, the treatment time can be significantly shortened, the amount of wastewater treated and the load can be reduced, the equipment can be reduced, and the cost can be reduced.

The peeling treatment of apples is mainly performed by mechanical peeling. However, the flesh is also lost with the removal of the hull (10% or more of the raw fruit), which has a great influence on the yield. If this invention technique is diverted, the yield of raw material fruit by peeling is expected to improve at once to nearly 99%, and it can be seen that the treatment cost of waste residue is greatly reduced.

In addition, the purchase cost, leasing fee, maintenance / operation cost, operator, etc. of the peeling machine are not required, and the floor area of the production process is minimized, which has a great effect of improving productivity.

1 Fruit 2 Fruit pulp from which the outer or inner pericarp has been removed 3 Peeling treatment liquid 4 Acid aqueous solution 11 Treatment tank 12 Net cage 13 Heater 14 Neutralization tank 21 Conveyor 22 Tray 23 Liquid transport pump 24 Nozzle

Claims (5)

Dissolve the outer or inner peel of the fruit using a peeling solution containing sodium hydroxide or potassium hydroxide, sodium hypochlorite, sodium chloride or potassium chloride, and a surfactant and having a pH of 10 or more and 14 or less. Or the first step of peeling and obtaining fruit flesh,
The second step of immersing the pulp in an acidic aqueous solution containing an organic acid and having a pH of 2 or more and 6 or less to neutralize the peeling treatment liquid, and
A method of peeling fruits, which comprises. The concentration of sodium hydroxide or potassium hydroxide in the peeling treatment liquid is 0.5% by weight or more and 10% by weight or less, and the concentration of sodium hypochlorite is 0.1% by weight or more and 5% by weight or less, and chloride. The method for peeling fruits according to claim 1, wherein the sodium concentration is 0.01% by weight or more and 5% by weight or less, and the surfactant concentration is 0.01% by weight or more and 5% by weight or less. .. The method for peeling fruits according to claim 1 or 2, wherein the first step is a treatment of immersing the fruits in a peeling treatment solution having a temperature of 30 ° C. or higher and 95 ° C. or lower for a time of 10 seconds or longer and 600 seconds or shorter. The method for peeling a fruit according to any one of claims 1 to 3, wherein the surfactant is a sucrose fatty acid ester. The method for peeling a fruit according to any one of claims 1 to 4, wherein the fruit is a grape fruit, an apple fruit, or a citrus fruit .

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