JP2981223B1 - Production method of pickled eggplant - Google Patents

Abstract

An object of the present invention is to provide a method for producing a pickled eggplant that maintains the natural color of the eggplant and does not cause dissolution of a chelating dye into a preservative solution or color transfer to the pulp. SOLUTION: A step (1) of immersing an eggplant or a slice thereof in an aqueous solution containing salt and alum and having a pH adjusted to 6 to 10 (hereinafter, referred to as a salt immersion liquid), and the obtained step (1). A step of immersing the eggplant or a slice thereof into an aqueous solution containing alum and cyclodextrins and having an osmotic pressure adjusted to 800 to 1800 milliosmometer units (hereinafter referred to as a preservation solution) (2) ).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing pickled eggplant. In particular, the present invention relates to a method for producing a pickled eggplant in which the natural color of the eggplant is maintained.

[0002]

2. Description of the Related Art Pickled vegetables are widely popular foods, and in the past, they were generally cooked at home. In recent years, people's lives have changed and the number of households cooking pickles has decreased, and at the same time, pickles as side dishes have gained commercial value and have become widely distributed. Most pickles in today's general retail stores are placed in transparent packaging so that consumers can check the contents. In order to obtain high commercial value of pickled vegetables, freshness of the appearance color is important, and in order to improve it, food coloring and the like have been used. However, as consumers are becoming more health-conscious, pickled vegetables, even if they are derived from vegetable-derived pigments, tend to shy away from unnatural colors when selected by general consumers. It became so.

[0003] In pickled eggplant, a technique of forming a bright blue-purple color by using alum to form a chelate with the anthocyanin-based natural pigment nasnin contained in eggplant peel has been reported since ancient times. However, this technique,
The brightly colored chelate dye elutes in large quantities in the preservative solution containing the seasoning at the same time, or causes color transfer to the pulp, so that consumers can determine that the food dye is used. Instead, it greatly impaired the product value. If the eggplant pickles can maintain the natural color of the eggplant instead of the vivid blue-purple color, and do not cause the dissolution of chelate dyes in the preservative solution containing seasonings or color transfer to the pulp, the product value will increase significantly. improves.

Accordingly, an object of the present invention is to provide a method for producing pickled eggplant that maintains the natural color of the eggplant and does not cause the dissolution of the chelate dye in the preservation solution or the color transfer to the flesh. is there.

[0005]

According to the present invention, an eggplant or a slice thereof is immersed in an aqueous solution containing salt and alum and adjusted to a pH of 6 to 10 (hereinafter referred to as a salt immersion liquid). An aqueous solution (hereinafter referred to as a preservation solution) comprising the step (1) and the obtained eggplant or a slice thereof, which is an aqueous solution containing alum and cyclodextrins and whose osmotic pressure is adjusted to 800 to 1800 milliosmometer units. ) Comprising a step (2) of immersion.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTIONStep (1)  In step (1), the eggplant or a slice thereof is salted and
An aqueous solution containing a bun, adjusted to pH 6-10
In the salt immersion liquid. In the step (1), a dye is colored,
The purpose is to stabilize, prevent elution and immobilize
You.

[0007] The salt immersion liquid contains at least salt and alum. Salt is a so-called salt, a component which sufficiently penetrates alum into eggplant or a slice thereof, acts on anthocyanin-based pigments contained in eggplant peel, and further helps stabilize and fix those colors in tissues. And a component that imparts a taste to eggplant or a slice thereof. The cation component contained in the salt may be calcium, magnesium, ammonium or the like in addition to sodium or potassium. However, calcium, magnesium, ammonium and the like may impair the taste depending on the concentration thereof. Further, when the salt concentration of the salt immersion liquid is too high, considering that it has a large effect on the texture of the pickled eggplant, the salt concentration of the salt immersion liquid is preferably 10 parts by weight or less per 100 parts by weight of the salt immersion liquid, preferably. Is suitably in the range of 3 to 5 parts by weight.

Alum (potassium aluminum sulfate)
Is an ingredient that acts on pigments of eggplant and causes the pigments of eggplant peels to develop and immobilize appropriately to give rich appearance.
Alum tends to lower the pH of the salt immersion liquid. The alum concentration of the salt immersion liquid is adjusted to pH 6 of the salt immersion liquid.
To adjust to 10 to 100 parts by weight of salt immersion liquid,
It is preferably at most 1 part by weight, more preferably at most 0.5 part by weight. Further, it is preferable that the alum concentration is determined in consideration of the size of the cut eggplant, its type, production place, growth conditions such as sunshine time and temperature at that time.

The salt immersion liquid is adjusted so that the pH is in the range of 6 to 10. If the pH of the salt immersion liquid is less than 6, there is a problem that the pigment of the eggplant that has formed a chelate with alum is easily eluted from the pericarp, and if it exceeds 10, the tissue of the eggplant or its section is deteriorated or the taste is remarkably deteriorated. There is a problem of causing. The pH of the salt immersion liquid tends to decrease as the immersion time elapses. The initial value of the pH of the salt immersion liquid is
It is preferably in the range of 8-9. Further, even after the immersion, the pH of the salt immersion liquid is preferably 6 or more.

Conventionally, the alum-containing salt immersion liquid used for the preparation of pickled eggplant contains more than 1 part by weight of alum per 100 parts by weight of the salt immersion liquid,
Alternatively, the pH was less than 6 because the alum crystals were rubbed into the eggplant fruit and excess alum was dissolved in the salt immersion liquid. As a result, even when using the preservation solution described below, if a conventional salt immersion solution having a pH of less than 6 is used, the resulting eggplant pickled product has an eggplant pigment that has developed a purple-purple color, so that the contents are not clearly visible. There is a problem that the color of the pulp is eluted in the preservation solution or the color of the pulp is unnaturally felt due to color transfer, thereby impairing the commercial value of the fruit.

When the action of some enzyme or fermentation by microorganisms is involved, or when the pH buffering action greatly affects the taste of the final product, the final pH in step (1) may be lowered. But at least,
It is preferable from the viewpoint of obtaining the effect of the present invention that the buffering action in the range of pH 6 to 10 is maintained for the first 1 to 4 hours of the operation of the step (1). In such a case, it is preferable to separately prepare a target salt immersion liquid having a low pH, and to use the salt immersion liquid having a low pH after immersion in the salt immersion liquid used in the method of the present invention.

For the purpose of adjusting the pH, the salt immersion liquid contains
A buffer may be included. As a pH buffer,
For example, disodium or potassium hydrogen phosphate,
Phosphates such as sodium or potassium dihydrogen phosphate, sodium or potassium tripolyphosphate, sodium or potassium metaphosphate, tetrasodium or potassium pyrophosphate, and sodium or potassium dihydrogen pyrophosphate Can be mentioned.
Organic acid salts can also be used as pH buffers, for example, sodium or potassium citrate, sodium or potassium succinate, sodium or potassium fumarate, sodium or potassium L-ascorbate, or sodium or potassium tartrate And the like. Furthermore, sodium or potassium salts of amino acids such as glutamic acid and aspartic acid and sodium or potassium salts of nucleic acids such as 5′-inosinic acid, 5′-uridylic acid, and 5′-ribonucleotide are also pH
It can be used as a buffer. However, although these amino acid salts and nucleic acid salts have the advantage of having a good taste to the product, they have the disadvantage that the buffering action is smaller than those described above, and they have the disadvantage that they are more easily contaminated by bacteria. Carefully mix according to the conditions used.

Further, for the purpose of preparing pH more finely,
Inorganic salts such as sodium or potassium hydroxide, carbonate, bicarbonate, nitrate, sulfate, chloride and the like and lower organic acid salts such as acetates can be used in combination with the above pH buffer.

The salt immersion liquid may contain various components as desired, in addition to the above components. For example, cyclodextrins contained in a preservation solution described below can be included. Examples of the cyclodextrin include α, β or γ-cyclodextrin consisting of 6, 7, or 8 glucose residues. Further, these cyclodextrins may be branched cyclodextrins having at least one kind of branched functional group selected from the group consisting of glucose and maltooligosaccharides. The amount of cyclodextrins contained in the salt immersion liquid is, for example, 5 parts by weight or less, preferably 2 parts by weight or less per 100 parts by weight of the salt immersion liquid.

The above components are dissolved in water to prepare a salt immersion liquid. It is desirable that the water used here avoid extreme hard water which would destroy the buffering action of the pH buffer. However, in order to obtain a predetermined pH according to the water quality, the amount of the alum to be added and salts having a pH buffering action can be increased or decreased. Also, when the amount of dissolved oxygen is large, the color tone of the eggplant is extremely deteriorated. Therefore, water can be boiled in advance, or an edible reducing agent such as ascorbic acid can be added in an amount that does not affect the pH buffering action of salts as an upper limit.

The eggplant immersed in the salt immersion liquid may be a whole or a section thereof. The size of the eggplant to be cut is preferably a bite size. If the eggplant is immersed without being cut in half or cut, the immersion liquid component does not permeate sufficiently, and the effect of the color tone improver aimed at by the present invention may not be obtained in some cases. There is no particular limitation on the temperature and time for immersing the eggplant in the salt immersion liquid.
An eggplant cut into an appropriate size is added in an amount sufficient to soak it in the pickling liquid, that is, 100 parts by weight or less, preferably 85 parts by weight or less, per 100 parts by weight of the pickling liquid.
It is appropriate to soak for a time. However, the immersion time varies depending on the variety of eggplant, the size of the cut eggplant, and the desired flavor of the final product.
If the size is about 1 cm, the division is preferably 3 to 4 hours. A temperature of, for example, room temperature or less is sufficient, but a temperature exceeding 25 ° C., which easily damages the eggplant pulp tissue, is not preferred.

[0017]Step (2)  In the step (2), the eggplant obtained in the step (1) or its eggplant
Remove the sections from the salt soak and alum and cyclo
Contains dextrins and has an osmotic pressure of 800-1800 millioz
Immersed in a preservative solution adjusted to
You.

The preservation solution contains at least alum and cyclodextrins. Alum (potassium aluminum sulfate) is a component that acts on pigments of eggplants and causes the pigments of eggplant peels to develop and immobilize the pigments in an appropriate manner to give rich appearance. The alum concentration in the preservation solution is preferably determined in consideration of the size of the cut eggplant, its type, place of production, growth conditions such as sunshine time and temperature at that time. Alum inhibits eggplant pigments from the action of cyclodextrin and promotes pigment elution from eggplants. Therefore, the amount is preferably 1 part by weight or less, more preferably 0.5 part by weight or less, based on 100 parts by weight of the preservative solution.

Cyclodextrin is a component which acts on eggplant dyes eluted in a preservation solution in a form easily affected by the action and suppresses color formation and browning due to chelate formation and oxidation with metal ions. Examples of the cyclodextrin include α, β or γ-cyclodextrin consisting of 6, 7 or 8 glucose residues. Further, these cyclodextrins may be branched cyclodextrins having at least one kind of branched functional group selected from the group consisting of glucose and maltooligosaccharides.

The concentration of cyclodextrin in the preservation solution is not limited as long as this effect can be effectively obtained. However, since the storage and distribution environment of the product manufactured in the present invention is maintained at a low temperature of at least about 10 ° C., the cyclodextrin is added with a dissolving amount capable of providing a stable solution at the distribution and storage temperature. It is desirable to set the upper limit. The saturated dissolution amount of cyclodextrin varies depending on the type of salt, seasoning, and the like used at the same time.For example, when β-cyclodextrin having the lowest dissolution amount is used, the distribution and storage temperature of the pickled eggplant is about 10 ° C. If present, 0.7 to 1 part by weight with respect to 100 parts by weight of the preservative solution, or 8 for α-cyclodextrin
Not more than 18 parts by weight of γ-cyclodextrin can be added. Economically, in order to maximize the effect, based on the amount of 0.3 to 1 part by weight of β-cyclodextrin per 100 parts by weight of the solution,
Α-cyclodextrin and / or γ-cyclodextrin, which are difficult to precipitate at a relatively low temperature, and / or a branched cyclodextrin derivative having these as a basic skeleton, can be produced according to the distribution and storage temperature in an auxiliary manner. It is most preferable to add them according to the quality of eggplant.

The preservation solution of the present invention is adjusted so that the osmotic pressure is in the range of 800 to 1800 milliosmometers. Osmotic pressure
If it is less than 800 milliozmometers, the taste and texture of the eggplant or its slices are reduced, the commercial value of the pickles cannot be obtained, and there is a problem of contamination by various germs and the storage stability thereof, and 1800 milliozmo If it exceeds the meter, there is a problem that the pigment of the eggplant peel is not stable, and is easily eluted in the preservative solution or easily transferred to the pulp. Conventionally, the preservative used for the preparation of pickled eggplant has an osmotic pressure of 3000 to 4000 millismometer. As a result, even if the salt immersion liquid described above is used, if a conventional preservation liquid having an osmotic pressure of 3000 to 4000 milliosmometer is used, the resulting pickled eggplant will have a preservation liquid of a blue-purple eggplant pigment. There is a problem that the dye is eluted into the preservation solution so that the contents are not sufficiently visible, or the color of the pulp is unnaturally felt due to color transfer, thereby deteriorating the commercial value of the product.

The osmotic pressure of the preservation solution can be adjusted by adding appropriate amounts of the following salts. Salts that can be used to adjust the osmotic pressure include, for example, alkali metals or alkaline earth metals such as sodium, potassium, magnesium, and calcium, and inorganic salts such as chlorides, sulfates, and carbonates, L -Glutamic acid, amino acid salts such as L-aspartic acid, 5'-inosinic acid, 5'-uridylic acid,
Nucleic acid salts such as 5'-ribonucleotide; and organic acid salts such as citric acid, succinic acid, fumaric acid, L-ascorbic acid and tartaric acid.

[0023] In addition to the above components, the preservation solution may contain various components, if desired, in addition to the above components. For example, the preservation solution can contain a salt. Salt is so-called salt. The cation component contained in the salt may be calcium, magnesium, ammonium or the like in addition to sodium or potassium. However, calcium, magnesium, ammonium and the like may impair the taste depending on the concentration thereof. However, if the salt concentration of the preservative solution is too high, it will greatly affect the texture of the pickled eggplant, so the salt concentration of the preservative solution should be in the range of 3 to 15 parts by weight based on 100 parts by weight of the preservative solution. Is appropriate.

Further, a seasoning may be added to the preservative solution. By adding a seasoning to the preservative solution used in step (2), the eggplant can be tasted more favorably by immersing it in the preservative solution containing the seasoning for a long time until the consumer eats it. Examples of the seasoning used herein include, for example, glucose, maltose, fructose, sucrose, maltooligosaccharides and fructooligosaccharides, lactose, trehalose, gentiobiose, nigerose, transfer sugars such as coupling sugar, or sugar alcohols such as sorbitol and maltitol. , Dextrins hydrolyzed starch, or a mixture containing one or more of these, soy sauce,
Fermented seasonings such as miso and fish sauce, brewed and distilled liquors or mixtures such as sake, shochu, soy sauce, wine and mirin, brewed vinegar, vegetables and meat other than eggplant, seafood, etc., or pastes thereof. An extract or the like can be used. Alternatively, a commercially available seasoning liquid or seasoning containing at least one of the above components can be used as it is.

A preservation solution is prepared by dissolving the above components in water. Also, when the amount of dissolved oxygen is large, the color tone of the eggplant is extremely deteriorated. Therefore, water can be boiled in advance, or an edible reducing agent such as ascorbic acid can be added.

The eggplant obtained in the step (1) is prepared by thoroughly draining the pickling solution, adding 50 to 200 parts by weight of the preservation solution having the above composition to 100 parts by weight of the eggplant, and adding a packaging material or container. And soak for a predetermined time. The temperature and time for immersing the eggplant in the storage solution are not particularly limited, but the temperature is suitably, for example, in the range of 4 to 10 ° C. However, the lower the temperature, the better from the viewpoint of preventing various bacterial contamination and excessive fermentation. The immersion time in the step (2) is 1 to
It may be about 7 days, but it depends on the quality of eggplant, the seasoning used for the preservation solution and the desired flavor, the processing time of step (1), the immersion temperature, etc. It is preferable to adjust the quality.

The preservation solution after sealing can protect the product quality from the temperature change to some extent and the ultraviolet irradiation from sunlight or a fluorescent lamp by the action of cyclodextrin and the like. However, when these physical influences are extreme, even if they are for a short time, the effects of protecting or improving the color tone of the preservative solution are irreversibly destroyed, as well as impairing the quality of the pickled product obtained. Sometimes. Therefore, it is desirable to avoid these effects as much as possible.

[0028]

According to the present invention, it is possible to produce pickled eggplant that maintains the natural color of the eggplant and does not cause the dissolution of the chelate dye into the preservative solution or the color transfer to the pulp.

[0029]

The present invention will be described in more detail with reference to the following examples. Example 1 A medium-sized eggplant fruit was halved vertically and cut into pieces each having a thickness of 1 cm, and 100 parts by weight were added to 126 parts by weight of three kinds of salt immersion liquids adjusted according to the compositions shown in Table 1 respectively. After soaking for an hour, the eggplant was taken out and sufficiently drained.

[0030]

[Table 1]

Transfer 10 parts by weight of the obtained immersed eggplant into a sealable vinyl bag, and further add 10 parts by weight of a preservative solution containing the three seasonings shown in Table 2, respectively. Was sealed and stored at 5 ° C. for 1 week.

[0032]

[Table 2]

Table 3 shows the visual comparison of the coloration in the vinyl bag of nine kinds of eggplant lightly pickled prototypes consisting of a combination of three kinds of salt immersion liquids and three kinds of preservatives containing seasonings. The result was obtained.

[0034]

[Table 3]

That is, in the case of only the prototype manufactured using a combination of the salt immersion liquid having the composition of the experimental system 1 and the preservative liquid containing the seasoning having the composition of the experimental system A, the eggplant peel was simultaneously packaged into the preservative liquid. Elegant eggplant shallow pickle was obtained, in which elution of the pigment from the origin and color transfer to the pulp were hardly observed.
The column in Comparative System 2 in Table 3 is more pH than the column in Experimental System 1.
Are low, but the three prototypes in this column are:
In each case, color elution into the preservation solution was observed. The row in Comparative System 3 in Table 3 has a higher content of aluminum potassium sulfate and a lower pH than the row in Experimental System 1. The three prototypes included in this row are the rows in Comparative System 2. 3
Compared with the seeds, more intense elution of the pigment and color transfer to the pulp were observed. The row in Comparative System B in Table 3 has a higher osmotic pressure than the row in Experimental System A, but the three types of prototypes contained in this row all have color elution into the preservative solution. Was observed. The row in Comparative System C in Table 3 does not contain β-cyclodextrin as compared to the row in Experimental System A, but the three prototypes included in this row all show color in the preservative solution. Was eluted.

Example 2 Instead of the composition of Experimental System 1 used in Example 1, a salt immersion liquid having a composition using sodium citrate shown in Table 4 was used.
The eggplant fruit cut in the same manner as in the example was immersed for 4 hours, and immersed in the preservative solution having the composition of the experimental system A used in the example 1 for one week in a sealed vinyl bag so that air did not enter.

[0037]

[Table 4]

The selected prototype was rich in eggplant, lightly pickled eggplant, almost equivalent to Example 1.

Example 3 A pickle preparation (1) having the composition shown in Table 5 was prepared and used to prepare a salt immersion solution and a preservative solution having the compositions shown in Tables 6 and 7, respectively.

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Table 7]

Eggplant fruit of medium size is halved vertically,
100 parts by weight of a 1 cm-thick piece was immersed in 126 parts by weight of the prepared salt immersion liquid for 6 hours, and then the eggplant was taken out and sufficiently drained. Transfer the obtained immersion eggplant to a sealable vinyl bag, add an equal amount of the prepared preservative solution containing the seasoning, seal the vinyl bag so that air does not enter inside,
Stored at 5 ° C. for one week. As a result, rich pickling of eggplant was obtained in which no elution or color transfer of pigment derived from eggplant peel was observed in the preservation solution and eggplant pulp.

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Claims (6)

(57) [Claims] 1. A step (1) of immersing an eggplant or a slice thereof in an aqueous solution containing salt and alum, wherein the pH is adjusted to 6 to 10 (hereinafter referred to as a salt immersion liquid), and Immersing the eggplant or a slice thereof into an aqueous solution containing alum and cyclodextrins, the aqueous solution having an osmotic pressure adjusted to 800 to 1800 milliosmometer units (hereinafter referred to as a preservation solution) ( 2. A method for producing pickled eggplant containing 2). 2. The method according to claim 1, wherein the salt immersion liquid contains 1 part by weight or less of alum per 100 parts by weight of the salt immersion liquid. 3. The method according to claim 1, wherein the preservative is 1 part by weight per 100 parts by weight of the preservative.
3. The method according to claim 1, wherein the alum contains not more than 1 part by weight of alum. 4. The production method according to claim 1, wherein the salt immersion liquid further contains cyclodextrins. 5. The production method according to claim 1, wherein the preservative solution further contains a seasoning. 6. Cyclodextrins comprising α, β and γ
-Cyclodextrin, and at least one selected from the group consisting of glucose and maltooligosaccharides;
The production method according to any one of claims 1 to 5, wherein the production method is at least one selected from the group consisting of branched cyclodextrins having a kind of branched functional group.