JP2008086258A - Peeling method of persimmon fruit and peeled persimmon fruit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a peeling method of persimmon fruit, peeling regardless of the kind and grade of maturity of persimmon fruit. <P>SOLUTION: This peeling method of persimmon fruit comprises a cuticle penetrating treatment process of producing injuries penetrating the cuticle of persimmon fruit on the cuticle by a cuticle penetrating means, a heat treating process of heating the persimmon fruit subjected to the cuticle penetrating treatment process by a heating means so as to inactivate the pectic substance splitting enzyme activity inhibitor contained in the persimmon fruit, an enzyme treatment process of impregnating the persimmon fruit subjected to the heat treating process with pectic substance splitting enzyme, and an outer fruit skin removing process of removing the outer fruit skin tissue of the persimmon fruit subjected to the enzyme treatment process by a removing means so as to obtain peeled fruit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for peeling oyster fruit and a peeled oyster fruit.

  Conventionally, peeling of vegetables, fruits, etc. has been done by using a blade, grinding machine, roll-like machine, using compressed air or steam, or by chemical treatment such as caustic soda alone or in combination. It is used in the state. Moreover, about the fruit etc. without such a dedicated peeling machine, the peeling of a hand is performed manually, and the present condition is that the general purpose system which peels a lot of fruit efficiently is not established.

  On the other hand, regarding the oyster fruit, the present applicant performs an enzyme treatment by impregnating the persimmon fruit tissue of the oyster fruit by impregnating the oyster fruit heated by the heating means with impregnated pectin degrading enzyme. A method for peeling oyster fruit to remove the outer skin was developed (see Patent Document 1).

  Further, Patent Document 2 below discloses an apparatus used for performing a method in which, after performing a heat treatment, perforation with a metal needle is performed on the surface of an oyster fruit and then an enzyme treatment is performed to peel the oyster fruit. It is disclosed. In this method of peeling oyster fruit, perforation with a metal needle is performed on the part where cracks are not generated in the heat treatment, thereby increasing the penetration of the enzyme in the subsequent enzyme treatment and promoting the disintegration of the pericarp tissue. is there. Furthermore, Patent Document 3 listed below describes a method for removing a citrus fruit skin by introducing an enzyme into a citrus fruit through a hole in the skin and weakening a bond between the skin and the pulp. Yes.

JP 2004-121242 A

JP 2005-253353 A

Japanese Patent Laid-Open No. 5-115268

  However, even if the method and apparatus for peeling oyster fruits described in Patent Document 1 or Patent Document 2 described above, there are oyster fruits that cannot be peeled depending on oyster fruit varieties and maturity. In the invention described in Patent Document 3, the target fruit is a citrus fruit, and even when the present invention is applied to an oyster fruit having a different outer skin structure, it cannot be peeled off successfully.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a method for peeling oyster fruits that can be peeled regardless of the varieties and maturity of oyster fruits.

  In order to achieve the above object, the method of peeling oyster fruit according to the present invention comprises a cuticle penetrating treatment step of causing a cuticle penetrating the cuticle of the oyster fruit by means of the cuticle penetrating means, and the cuticle. The oyster fruit that has undergone the penetration process is heated by a heating means to inactivate the pectin degrading enzyme activity inhibitor contained in the oyster fruit, and the pectin substance to the oyster fruit that has undergone the heat treatment process An enzyme treatment step for impregnating with a degrading enzyme and a skin peel removing step for removing peeled skin tissue of the oyster fruit that has passed through the enzyme treatment step with a removing means to obtain peeled fruit are provided.

  Moreover, in the said structure, a sharp protrusion is used as a cuticle penetration means used at a cuticle penetration process.

  And in each above-mentioned structure, the enzyme treatment temperature in an enzyme treatment process is 15 degreeC or more and 37 degrees C or less, It is characterized by the above-mentioned.

Further, in each configuration described above, the pitch between a plurality of wounds generated in the cuticle in the cuticle penetration treatment step is 3 mm or less on average, and the enzyme treatment temperature (X) and enzyme in the enzyme treatment step The relationship with the processing time (Y) is the following formula (I), (II);
Y ≦ −0.33X + 15.3 (I)
Y ≧ −0.23X + 9.41 (II)
(However, X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours))
It is shown by.

Further, in each of the above-described configurations, the pitch between a plurality of scratches generated in the cuticle in the cuticle penetration treatment step is 3 mm or more and 6 mm or less on average, and the enzyme treatment temperature (X) in the enzyme treatment step And the enzyme treatment time (Y) are represented by the following formulas (III) and (IV);
Y ≦ −0.42X + 20.4 (III)
Y ≧ −0.25X + 12.3 (IV)
(However, X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours))
It is shown by.

  When heat treatment is performed in the heat treatment step without passing through the cuticle penetration treatment step, oyster fruits that do not cause cracks in the cuticles or oyster fruits that cause local cracks are used as raw materials.

  Furthermore, it is the peeled oyster fruit obtained by the peeling method of the oyster fruit which has said each structure.

  According to the method for peeling off oyster fruit according to the present invention, a wound penetrating the cuticle is caused by the cuticle penetration means in the cuticle penetration treatment step, and the pectin degrading enzyme activity inhibitor is inactivated in the heat treatment step. In addition, the oyster fruit is impregnated with pectin-degrading enzyme in the enzyme treatment process to disrupt the pericarp tissue of the oyster fruit, and the pericarp tissue of the oyster fruit is removed by a removing means in the pericarp removal process to remove the peeled fruit. To get. Therefore, it is not possible to cause scratches penetrating the cuticles only by performing heat treatment, and even oyster fruits of a variety or ripeness that could not be peeled can be peeled.

  Moreover, when a sharp protrusion is used as the cuticle penetrating means used in the cuticle penetrating treatment step, it is possible to reliably cause a flaw penetrating the cuticle in a short time.

  And when the enzyme treatment temperature in an enzyme treatment process is 15 degreeC or more and 37 degrees C or less, oyster fruit can be peeled without impairing the hardness of an oyster.

  Furthermore, the relationship between the enzyme treatment temperature (X) and the enzyme treatment time (Y) is expressed by the above formula (I) according to the pitch between a plurality of wounds generated on the cuticle in the cuticle penetration treatment step. , (II), or (III) or (IV), when processing a large amount of oyster fruit industrially, the pitch between multiple wounds and the enzyme treatment temperature (X) If adjusted, an optimum peeled oyster fruit can be obtained by performing the enzyme treatment for the enzyme treatment time calculated from the above formula. Therefore, the enzyme treatment time can be selected according to the working conditions, and the working efficiency can be improved.

  The best embodiment of the present invention will be described. The oyster fruit to which the method of the present invention is applied is a fruit of a plant known by the scientific name of Diospyros kaki belonging to the family Oysteraceae. Of different varieties.

  By the way, as shown in FIG. 1, the outer pericarp tissue of oysters is composed of four layers such as a cuticle, an epidermis, a subepidermis, and stone cells in order from the outside. Of these, the cuticle is particularly strong and plays an important role in protecting the pulp. The cuticle has a dense tissue and water repellency on the surface, whereas the outer skin structure inside the cuticle is relatively sparse.

  Oyster fruits can be classified into three groups according to the difference in the damaged state of the pericarp when heated by heating means without going through the keratin penetration treatment step. That is, when heat treatment is performed at 100 ° C. for 30 seconds to 60 seconds without the cuticle penetration treatment, cracks are generated only in local areas such as group A, the top of the fruit, and the periphery thereof, where the entire cuticle is cracked. Group B and group C where cracks hardly occur in the cuticle. In addition, the conditions of this heat processing are the ranges in which the hardness of the flesh of an oyster fruit does not fall, and a taste, a flavor, etc. do not change.

  Oyster fruits belonging to Group A can be cracked, which is a scratch that penetrates the cuticle in the entire cuticle in the heat treatment process without performing the cuticle penetration treatment. Peeling is possible by performing a heat treatment step, an enzyme treatment step, and an outer skin removal step. Examples of the oyster fruit varieties belonging to Group A include plain nuclei and tone sorghum.

  When oyster fruits belonging to Group B are heat-treated without keratin penetration treatment, cracks are generated only in the local areas such as the fruit top and its concentric peripheral parts. Therefore, in the subsequent enzyme treatment step, only the cracked local part can be impregnated with the pectin degrading enzyme, and the part not impregnated with the pectin degrading enzyme cannot be peeled. Examples of varieties of oyster fruits belonging to Group B include Ichida, Saijo, Aoi, and Sansha-an.

  When oyster fruits belonging to Group C are heat-treated without keratin penetration, there is little or no crack in the keratin, so that in the subsequent enzyme treatment step, pectin is applied to the outer pericarp tissue inside the keratin. It cannot be impregnated with a degrading enzyme. Therefore, even if each subsequent process is performed without going through the cuticle penetration process, peeling is impossible.

  The cuticle penetration processing step is an embodiment as long as the cuticle penetrates the cuticle on the surface of the oyster fruit evenly and causes perforations and cracks that penetrate the cuticle uniformly throughout the cuticle. It doesn't matter. Scratches uniformly generated on the entire surface of the cuticle serve as a starting point for cracks generated in the cuticle during the heat treatment. Therefore, the oyster fruit that has undergone the cuticle penetration step and the heat treatment step can cause uniform cracks in the cuticle, and the pectin-degrading enzyme is removed from the inside of the cuticle in the subsequent enzyme treatment step. The pericarp tissue can be impregnated very efficiently.

  As the cuticle penetrating means, the embodiment is not limited as long as such cuts can be uniformly generated on the cuticle of oyster fruit. For example, sharp protrusions such as sword mountain, metal needle or grater, file, ice Blasting or the like is used. If a commercially available sword mountain, file, grater or the like is used, the cuticle penetrating means can be realized at low cost. Further, when a sharp protrusion such as a sword mountain, a metal needle, or a grater is used, such a flaw can be surely generated in a short time.

  The average pitch between the scratches generated on the cuticle in the cuticle penetration treatment step is preferably about 6 mm or less. The pitch between the scratches is an average value when the distance between the approximate center position of a certain scratch and the approximate center position of another scratch is measured between a plurality of scratches. However, when the scratch has an elongated shape such as a crack, it means an average value obtained by measuring the distance between the central portion in the width direction of a certain scratch and the central portion in the width direction of another scratch at a plurality of positions.

Therefore, for example, when the shape of the scratch is, for example, a substantially circular shape, it is the average value of the center-to-center distance between the scratches, and the shape of the scratch is a substantially triangular shape, a quadrangular shape, a polygonal shape, or an irregular shape. Is the distance between the position considered to be approximately the center of the wound. Further, one size wound its area, 0.008 mm ² to 0.8 mm ^2, preferably 0.03 mm ² to 0.5 mm ^2. For example, when the scratch is substantially circular, the diameter is 0.1 mm to 1 mm, preferably 0.2 mm to 0.8 mm.

  When the pitch between the scratches is 6 mm or less, the area of the scratched portion is not too small, and there are a large number of scratches that act as starting points during the heat treatment, and the cuticle is uniform. Very fine cracks can be generated. Furthermore, when the pitch between the scratches is 3 mm or more and 6 mm or less on average, the area where the scratches are generated is smaller than that on the average 3 mm or less. Less damage is required. Therefore, when the peeled oyster fruit is used as a cut fruit or the like, the appearance can be improved.

  The heat treatment step is an embodiment as long as it has a function of inactivating the pectin degrading enzyme activity inhibitor contained in the oyster fruit by heating the oyster fruit that has undergone the cuticle penetration treatment step with a heating means. However, it is desirable that it is a process that can heat-treat the fruit surface in a short time. Here, in this process, it is thought that it has the function to produce a new crack, such as a crack and a damage, in the part where the scratch did not occur in the cuticle penetration process. As long as the heat treatment conditions are in a range that does not affect the hardness of the pulp, the condition may be such that the cuticle is peeled from or detached from the outer skin structure. Moreover, also in the heat treatment process, it was considered that the immersion of the enzyme in the enzyme treatment process could be promoted by causing scratches on the cuticle.

  Examples of the heating means in the heat treatment step include hot water, superheated steam, hot air, and the like. Among them, hot water is suitable for heating for a short time because it has a large sensible heat per capacity, and is easy to use. When such hot water is used, hot water from 80 ° C. to 100 ° C., more preferably from 95 ° C. to 100 ° C. is preferable. The amount ratio of oyster fruit to be added to hot water is desirably 50 to 100 L of hot water with respect to a ratio at which a decrease in water temperature is suppressed within 5 ° C., for example, 10 kg of oyster. The heat treatment time is preferably as short as possible in order to prevent softening of the pulp. For example, when the water temperature is 98 ° C., it is 30 seconds to 120 seconds, more preferably 60 seconds to 90 seconds.

  Inactivating the pectin degrading enzyme activity inhibiting factor is a tradeoff between the heating temperature and the heating time. For example, when hot water at 98 ° C. is used, the heating time is preferably 30 seconds or more.

  The oyster fruit after the heat treatment can be quickly cooled to minimize degradation of the pulp quality. Although the embodiment of the oyster fruit can be cooled as long as the surface temperature of the oyster fruit can be lowered to 40 ° C. or less within 30 seconds, it is usually achieved by immersing the fruit in running water or ice water.

  The pectin degrading enzyme used in the enzyme treatment step of the present embodiment is one produced by microorganisms or synthesized as long as it has an activity of acting on insoluble protopectin to disrupt plant tissue, so-called maceration activity. May be used, and it may be used alone or in combination of two or more.

  Such pectin degrading enzymes include protopectinases (Methods in Enzymology, 161, 335, 1988) produced by yeasts and yeast-related microorganisms such as Trichosporon penicillatum, Aspergillus awamori (Aspergillus awamori). ) Derived polygalacturonases (Biochem. Biophys. Biotech., 64, 1337 and 1729, 2000), polymethoxygalacturonases derived from Trichosporon penicillatum (FEBS Letters, 414, 439, 1997) Protopectinase-S (Methods in Enzymology, 161, 335, 1988) produced by the Tricospolone penicillatam SNO3 strain is particularly preferred.

  In the enzyme treatment step of the present embodiment, the pectinolytic enzyme can be used in any form of liquid or solid, but it affects the enzyme action like water, buffer solution, preferably distilled water. It can be used as an enzyme-containing liquid in which an enzyme is dissolved in a non-liquid. The oyster fruit is impregnated with the pectin degrading enzyme. The oyster fruit is immersed in the enzyme-containing liquid, or the enzyme-containing liquid is poured onto the surface of the oyster fruit, sprayed, or applied. Can be mentioned.

  When the temperature of the enzyme-containing liquid is 10 ° C. or higher, the function of the enzyme does not become weak and the enzyme treatment does not take a very long time, which is efficient. When the temperature is 55 ° C. or lower, there is no problem that the oyster fruit is easily softened, and no other microorganisms contained in the enzyme-containing liquid grow and contaminate the oyster fruit. In addition, when the enzyme treatment temperature is 15 ° C. or higher and 37 ° C. or lower, a more optimal state can be achieved in terms of oyster hardness and efficient treatment.

  When oyster fruits are immersed in the enzyme-containing liquid, for example, the temperature of the enzyme-containing liquid is 10 ° C. or higher and 55 ° C. or lower, preferably 15 ° C. or higher and 37 ° C. or lower, more preferably 25 ° C. or higher and 37 ° C. or lower. Is immersed for 1 hour to 14 hours, preferably 2 hours to 12 hours. In this way, the pericarp tissue can be disrupted by infiltrating the enzyme from the wounded part of the cuticle to the pericarp tissue.

The relationship between the enzyme treatment temperature (X) and the enzyme treatment time (Y) when oyster fruits are immersed in the enzyme-containing solution is as follows. When the pitch between the wounds is 3 mm or less on average, the enzyme treatment temperature (X ) And enzyme treatment time (Y) are represented by the following formulas (I) and (II):
Y ≦ −0.33X + 15.3 (I)
Y ≧ −0.23X + 9.41 (II)
(Where X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours)),
It is desirable to be in the range indicated by.
In addition, when the average pitch between the scratches is 3 mm or more and 6 mm or less, the relationship between the enzyme treatment temperature (X) and the enzyme treatment time (Y) in the enzyme treatment step is expressed by the following formulas (III), ( IV);
Y ≦ −0.42X + 20.4 (III)
Y ≧ −0.25X + 12.3 (IV)
(Where X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours)),
It is the range shown by.

  If the enzyme treatment is performed at a temperature and time within such a range, the hardness of the oyster will not be impaired, and the tactile sensation will be excellent. In addition, since the outer skin tissue can be sufficiently disintegrated, the outer skin can be easily removed in the outer skin removal step. Furthermore, since the enzyme is not excessively permeated into the fruit, there is no occurrence of damage inside the oyster fruit in the enzyme treatment process.

  When processing a large amount of oyster fruit industrially, for example, by adjusting the conditions of the cuticle penetration treatment such as the size and density of the wound, and selecting the optimum enzyme treatment temperature (X) for the working conditions, the above The enzyme treatment time (Y) calculated from the formulas (I) to (IV) can be selected from a minimum of about 1 hour to a maximum of about 14 hours. Therefore, the enzyme treatment can be performed according to the working conditions, which is very efficient.

  For example, when it is desired to peel the skin quickly, scratches are generated so that the pitch between the scratches is 3 mm or less on average in the cuticle penetration treatment step, and the enzyme treatment is performed at about X = 37 ° C. . In this case, the enzyme treatment time (Y) is Y ≧ −0.23 × 37 + 9.41 = 0.9 (hours) from the formula (II), that is, the enzyme treatment is performed to the extent that it is less than 1 hour. It becomes possible.

  In addition, when it is desired to perform the enzyme treatment for a long time at night or the like, in the cuticle penetration treatment step, the wound is caused to have an average pitch of 3 mm or less and the enzyme in the enzyme treatment step The treatment temperature (X) is about 15 ° C., and the enzyme treatment time (Y) is Y ≦ −0.42 × 15 + 20.4 = 14.1 (hours) from the formula (III), that is, about 14 hours. By doing so, an optimal peeled oyster fruit can be obtained. Therefore, for example, the oyster fruit that has undergone the heat treatment process at the end of the night work such as 10:00 pm may be immersed in the enzyme and taken out at about 0:00 pm the next day. In this way, there is no need to wake up at night and take out the oyster fruit from the enzyme solution, and the work burden can be greatly reduced.

  In addition, when the enzyme treatment is performed at a low temperature of 20 ° C. or less, preferably around 15 ° C., the microorganisms do not grow very actively, so that the microorganisms present in the enzyme treatment solution used are oyster fruits during the enzyme treatment. Can be deterred.

  The pectin-degrading enzyme described above depends on the enzyme and the type of target oyster fruit, but is usually used at a concentration of 100 to 500,000 U (international unit) per kg of oyster fruit, specifically 200 to 400,000 U. The enzyme-containing liquid is preferably prepared in such an amount that the enzyme concentration is within the above-mentioned range and all oyster fruits are immersed. Moreover, the solution prepared to the said density | concentration can be used also when flowing and spraying an enzyme containing liquid on an oyster fruit, and apply | coating.

  In addition, the impregnation procedure, the impregnation time, and the like are arbitrary as long as the pectin degrading enzyme can be impregnated into the pericarp tissue inside the cuticle. For example, the enzyme-containing liquid may be added to a container containing oyster fruit, or the oyster fruit may be added to a container containing the enzyme-containing liquid in advance. In addition, the impregnation procedure and the impregnation time are arbitrary when the enzyme-containing liquid is flowed down, sprayed and applied to oyster fruits.

  In the outer skin removal step of the present embodiment, the outer skin tissue after the enzyme treatment is removed from the fruit surface by the removing means. Such removal means is not particularly limited as long as it does not take time and does not damage the fruit surface after removal of the outer skin tissue, for example, rubbing by hand, rotating brush, etc. Examples of mechanical devices that combine the above are given. By the way, if the outer skin tissue is removed using running water, the enzyme will be removed and the flesh will not ripen. It is also possible to remove the pericarp tissue by wiping the fruit surface with hand in running water. When a rotating brush is used, the pericarp tissue can be removed with a very small pressing force, and the power cost is low.

  From the above, it is possible to peel over the entire epidermis of oyster fruits even if they belong to group B that could only be peeled locally by the conventional peeling method and group C that could not be peeled at all. It becomes. That is, in the cuticle penetration treatment step, a cut that penetrates the cuticle is caused on the entire surface of the oyster fruit by the cuticle penetration means, and this flaw serves as a starting point for a crack generated in the cuticle during the heat treatment. Therefore, the oyster fruit that has undergone the keratin penetration process and the heat treatment process can cause uniform cracks in the keratin, and can be peeled by an enzyme regardless of the variety and ripeness of the oyster fruit.

  The partial enlarged photograph of the oyster fruit which performed the cuticle penetration process process and the heat processing process in FIG. 2 is shown. From FIG. 2, it can be seen that the fine holes, which are scratches generated in the cut-penetration process, are the starting points when cracks are generated in the heat treatment process, and very fine and uniform cracks are generated over the entire surface. On the other hand, FIG. 3 is a partially enlarged photograph of the oyster fruit that was only subjected to the heat treatment step without performing the cuticle penetration step, and it can be seen that fine cracks did not occur as compared to FIG.

  In addition, if the peeling method according to the present embodiment is performed, it is possible to peel unripe immature fruits belonging to group A, where there was something that could not be peeled conventionally, and the work of selecting unripe oyster fruits becomes unnecessary. . Therefore, even if the hardness, tension, and cell composition of the fruit surface differ depending on the variety and ripeness of oysters, all oyster fruits can be peeled without sorting, and productivity can be improved. Costs such as labor costs can be kept low.

  In addition, the peeled fruit of the oyster obtained by the method of this embodiment can be utilized as a food as it is. Further, the peeled fruit can be subjected to secondary processing to produce various foods such as jelly and sheep pods, or dried cocoons and anpo rice cakes.

  When the food is used as it is, after the peeled fruit is immersed in an ascorbic acid aqueous solution or the like, the peeled fruit is packaged in a hermetically sealed manner with a synthetic resin film having a property that does not allow gas such as air to permeate, so-called gas barrier properties. Then, the packaged peeled fruit that has been hermetically packaged is heated to a predetermined temperature. The predetermined temperature is a temperature at which the used pectin degrading enzyme can be inactivated and microorganisms mixed in the package can be sterilized, and is about 60 ° C., for example. The temperature required for such heating varies depending on the heating time. For example, in the case of long-time heating, it may be about 50 ° C., but in the case of industrially desired short-time heating, it is preferably 85 ° C. or higher. Thus, the packaged peeled fruit after heating can be stored for several weeks by refrigerated storage, and can be distributed to the market as cut fruit.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these Examples.

Example 1.
Ichida oysters belonging to Group B are harvested in immature (unripe fruit), suitable ripening period (suitable ripening fruit), and in suitable ripening period, and packed in polyethylene film. Each of the oyster fruits was used for 3 sections of the one stored at 5 ° C. for 1 month (stored fruit). The cuticle penetrating treatment was carried out under the condition that the surface of the fruit was scratched with an average pitch of 3 mm or less using a sword-shaped metal needle. It was confirmed by image analysis that the shape of the scratch was approximately circular, the number of scratches per cm ² was 40-50, and the size of the scratch was about 0.5 mmφ. Thereafter, oyster fruits were immersed one by one in 3 L of hot water at 100 ° C., heat-treated for about 60 seconds, and then heat-treated by quenching with running water. Pretreatment was completed by the above-mentioned cuticle penetration process and heat treatment process.

  Then, in the enzyme treatment step, a 0.1 wt% aqueous solution of this enzyme was prepared using Pectinase-GODO (a pectin-degrading enzyme derived from Trichosporon penicillatum, joint liquor purification), which is a pectin degrading enzyme, and 650 mL thereof was prepared in a 1000 mL beaker. Put in. The enzyme aqueous solution was preheated in a constant temperature bath set at 37 ° C. When the aqueous enzyme solution reached 37 ° C., two oyster fruits, in which the cuticle was previously damaged by the cuticle penetration treatment and the heat treatment, were immersed in the aqueous enzyme solution. The beaker was transferred to a thermostat and kept at 37 ° C., and oyster fruit was taken out after 2 hours. The pericarp tissue was disrupted by the above enzyme treatment.

  Furthermore, in the pericarp removal step, the disintegrated pericarp tissue was removed by gently rubbing the oyster fruit treated with the enzyme by hand in running water. The remaining state of the pericarp tissue was judged visually and evaluated by a five-step peel score.

Comparative Example 1
The pretreatment is replaced with a method of performing a heat treatment after the cuticle penetration treatment, a method of performing only the cuticle penetration treatment and not performing the heat treatment (Comparative Example 1-1), or only a heat treatment without performing the cuticle penetration treatment. The pretreatment was performed under the two conditions of performing method (Comparative Example 1-2). The other conditions were the same as in Example 1. The oyster fruit was peeled, the remaining state of the pericarp tissue was judged visually, and the five-step peel score was evaluated.

Table 1 below shows the peel scores of Example 1 and Comparative Examples 1-1 and 1-2 obtained as described above.

The numerical values in Table 1 are five levels of peel score evaluated according to the state of the pericarp tissue after the enzyme treatment, and show the average values of samples of about 5 to 8 samples.
The contents of the “peeling score” in the table are as follows.
1: No change.
2: The cuticle can be peeled locally.
3; The pericarp tissue is locally collapsed.
4: The pericarp tissue is largely collapsed.
5: The pericarp tissue is completely disintegrated.

  As shown in Table 1, in Example 1, the pericarp tissue was disintegrated almost completely in the fruits of each ripening stage. In Comparative Example 1-1, the pericarp was not disintegrated in any oyster fruit of immature, appropriate ripeness, and storage fruit, and peeling was impossible at all. In Comparative Example 1-2, the outer pericarp tissue did not collapse.

  From the above results, in order to peel oyster fruits belonging to Group B by enzyme treatment, it is necessary to perform both cuticle penetration treatment and heat treatment. At that time, it is necessary to generate scratches penetrating the cuticle such as cracks and damage of the cuticle in the cuticle penetration treatment process, and the pectin degrading enzyme inhibitor present in the peel tissue is inactivated in the heat treatment process. It is considered necessary.

Comparative Example 2
The oyster fruit was peeled off in the same manner as in Example 1 except that the pretreatment order was changed and the cuticle penetration treatment was performed after the heat treatment, and the remaining state of the pericarp tissue was visually determined. Evaluation was based on the stage peel score.

  Table 2 below shows the peel score of Comparative Example 2 obtained as described above.

The numerical value of the peeling score in Table 2 is the same as the peeling score shown in Table 1.
As shown in Table 2, when the order of pretreatment was changed in Comparative Example 2, the peel score was lower than in Example 1, and the pericarp tissue was locally collapsed, or the cuticle was only locally peelable. there were. As in Example 1, this causes scratches on the fruit surface by the cuticle penetration treatment first, and then causes further cracks and damage to the portions that are not scratched by the cuticle penetration treatment by heat treatment, It is considered that the enzyme penetration efficiency in the enzyme treatment process was greatly improved. Therefore, it is considered that the action efficiency of the enzyme is increased, and the entire peeling of the oyster fruit becomes possible.

  In addition, when the cuticle penetration treatment is performed after the heat treatment as in Comparative Example 2, the oyster fruit is considered to be damaged and softened in the heat treatment. Further damaging or damaging the softened fruit surface by the cuticle penetration treatment is not a preferable state for the fruit, and damage to the flesh portion becomes excessive. Therefore, it can be said that it is not a realistic method, considering that peeling is insufficient.

Example 2
The oyster fruit was peeled off in the same manner as in Example 1 except that it was changed to Ichida tsumugi and Fuyu persimmon belonging to group C was used. The score was evaluated.

Comparative Example 3
The oyster fruit was peeled off in the same manner as in Comparative Example 1 except that Ichida mochi was used instead of Ichida mochi, and the remaining state of the pericarp tissue was visually determined and evaluated based on a 5-step peel score. .

  The peeled scores of Example 2 and Comparative Example 3 obtained as described above are shown in Table 3 below.

The numerical value of the peeling score in Table 3 is the same as the peeling score in Table 1.
The numerical values in Table 3 are the same as the peel scores in Table 1. As shown in Table 3, in Comparative Example 3-1, the pericarp was not disintegrated in any matured oyster fruit, and peeling was impossible at all. Also in Comparative Example 3-2, the outer pericarp tissue did not collapse. In contrast, in Example 2, the pericarp tissue was almost completely disintegrated in the fruits of each ripening period. Based on the above results, the pectin-degrading enzyme inhibitor that causes cracking, damage or detachment of the cuticle by both the cuticle penetration treatment and the heat treatment and is present in the outer peel skin tissue also in Togashi-an that belongs to Group C. It has been shown that inactivation is necessary to complete the peeling process.

Comparative Example 4
The oyster fruit was peeled off in the same manner as in Comparative Example 2 except that Fuyu Ichi was used instead of Ichida mochi, and the remaining state of the pericarp tissue was visually determined and evaluated based on a 5-step peel score. . Table 4 below shows the peel score of Comparative Example 4 obtained as described above.

The numerical value of the peeling score in Table 4 is the same as the peeling score in Table 1.
As shown in Table 4, when the order of the pretreatment was reversed and the cuticle penetration treatment was performed after the heat treatment, the peel result equivalent to that of Example 2 could not be obtained. This is the same result as that of Satoshi Ichida, and it was shown that the pretreatment for applying the cuticle penetration treatment after the heat treatment is not appropriate as a pretreatment method for the skinning method using an enzyme.

Example 3
The relationship between the enzyme reaction temperature and time for optimal peeling was investigated. Similar to the method described in Example 1, using a suitable ripe fruit of Fuyu varieties, using a sword-shaped metal needle, the depth of 0.1 mm so that the average pitch between the scratches is 3 mm or less on the fruit surface. A cuticle penetration treatment was performed under the conditions of scratches having a diameter of 0.5 mm and an opening diameter of 0.5 mmφ, and a heat treatment was performed in the same manner. Here, the sword-shaped metal needle has a diameter of 1 mm, a length of 11 mm, a number of 88, a houndstooth or square lattice, and a pitch of 3.5 mm.
In the enzyme treatment, in the enzyme treatment, the outer pericarp tissue is completely peeled every 2 hours without the influence of the enzyme in the test sections of 15 ° C., 25 ° C. and 37 ° C., It was measured whether the peeling was performed optimally. The results of Example 3 are shown in FIG.

Example 4
Next, the relationship between the enzyme reaction temperature and time was examined in the same manner as in Example 3 except that the condition of the cuticle penetration treatment was performed so that the average pitch between the scratches was 3 mm to 6 mm. Went. It was confirmed by image analysis that the shape of the scratch was approximately circular, the number of scratches per 1 cm ² was 4-10, and the size of the scratch was approximately φ0.5 mm. The results of Example 4 are shown in FIG. 5 below.

  In FIGS. 4 and 5, “●” indicates what was optimally peeled when 95% or more was optimally peeled (optimum), and “△” indicates incomplete peeling or pulp part The case where the influence of the enzyme has reached 5% or more is present, and the optimum state is not reached, but it is determined to be appropriate (suitable). The two straight lines indicate the upper and lower limits of the optimum range, and the upper straight line L in FIG. 4 indicates the equation (I). Also, the lower straight line M in FIG. 4 represents the equation (II). Further, the upper straight line N in FIG. 5 represents the equation (III), and the lower straight line O in FIG. 5 represents the equation (IV).

  From FIG. 4 and FIG. 5, the peeled oyster fruit that is optimum for each condition of the cuticle penetration treatment within the range represented by the above formulas (I) to (II) and the range represented by (III) to (IV). It can be seen that Moreover, it is possible to obtain an optimal peeled oyster fruit by enzyme treatment for about 2 hours, which is the shortest time, by performing the enzyme treatment at 37 ° C. on average with a pitch between the wounds of 3 mm or less. It was shown that. In addition, the average pitch between the wounds is 3 mm or more and 6 mm or less, and by performing the enzyme treatment at 15 ° C., the optimum peeling can be achieved by the enzyme treatment for about 12 hours which is the longest time. Indicated. In addition, these data take the average value of what has individual differences by ripening of oyster fruits, etc., and has variation. In addition, enzyme treatment at a temperature lower than 15 ° C. or higher than 37 ° C. is also possible. If the enzyme treatment is carried out at a temperature of 15 ° C. or higher, the enzyme treatment is completed within about 12 hours, so that it does not take too much time and the problem of the enzyme remaining in the stone cells does not occur. Further, if the enzyme treatment is performed at 37 ° C. or lower, there is no inactivation of the enzyme or softening of the pulp.

  Thus, by changing the conditions of the cuticle penetration treatment and the enzyme treatment temperature, the enzyme treatment time for obtaining the optimum peeled oyster fruit can be freely determined. Therefore, it is possible to cope with various work schedules such as peeling in a short time and peeling that can be left for a long time.

It is a section lineblock diagram showing the pericarp of a common oyster fruit. It is the elements on larger scale of the state which heat-processed the oyster fruit which concerns on one Embodiment of this invention after cuticle penetration processing. It is the elements on larger scale of the oyster fruit concerning the conventional peeling method. It is a figure which shows the relationship between the enzyme treatment temperature which concerns on other embodiment of this invention, and time. It is a figure which shows the relationship between the enzyme treatment temperature which concerns on another embodiment of this invention, and time.

Claims (6)

A cuticle penetration treatment step in which a cut through the cuticle is caused by the cuticle penetrating means on the cuticle of the oyster fruit, and the oyster fruit that has undergone the cuticle penetration treatment step is heated by the heating means, A heat treatment step for inactivating the contained pectin degrading enzyme activity inhibiting factor, an enzyme treatment step for impregnating the oyster fruit that has undergone the heat treatment step with a pectin degrading enzyme, and an oyster fruit that has undergone the enzyme treatment step A method for peeling off oyster fruit, comprising a step of removing the outer skin of the skin by a removing means to obtain a peeled fruit. The method for peeling oyster fruit according to claim 1, wherein a sharp protrusion is used as the means for penetrating the cuticle used in the cuticle penetrating treatment step. The pitch between a plurality of scratches generated on the cuticle in the cuticle penetration treatment step is 3 mm or less on average, and the relationship between the enzyme treatment temperature (X) and the enzyme treatment time (Y) in the enzyme treatment step is as follows: Formulas (I) and (II) of
Y ≦ −0.33X + 15.3 (I)
Y ≧ −0.23X + 9.41 (II)
(Where X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours)),
The method for peeling oyster fruit according to claim 1 or 2, characterized by: The pitch between a plurality of wounds generated in the cuticle in the cuticle penetration treatment step is 3 mm or more and 6 mm or less on average, and the enzyme treatment temperature (X) and enzyme treatment time (Y) in the enzyme treatment step The following formulas (III) and (IV):
Y ≦ −0.42X + 20.4 (III)
Y ≧ −0.25 + 12.3 (IV)
(Where X: enzyme treatment temperature (° C.), Y: enzyme treatment time (hours)),
The method for peeling off oyster fruit according to claim 1 or 2, wherein When heat treatment is performed in the heat treatment step without passing through the cuticle penetration treatment step, oyster fruits that do not cause cracks in the cuticles or oyster fruits that cause local cracks are used as raw materials. The method for peeling oyster fruit according to any one of claims 1 to 4.   The peeled oyster fruit obtained by the peeling method of the oyster fruit as described in any one of Claims 1 thru | or 5.