JP4350795B1 - Dried ginger and method for producing the same - Google Patents

Abstract

An object of the present invention is to solve the problems of conventional dry ginger that cannot be grated with a grater and has a complicated manufacturing process.
A porous dried ginger obtained by freeze-drying a raw rhizome ginger, wherein at least a part of the dried ginger is formed so that the shape of the raw rhizome ginger can be maintained. Cell shape is preserved.
[Selection] Figure 1

Description

  The present invention relates to a dried ginger and a method for producing the same, and more particularly to a dried ginger obtained by freeze-drying raw rhizome ginger and a method for producing the same.

Ginger is also used as a condiment such as tempura and cooking, or as a beverage such as ginger hot water. The ginger used in this way is mainly a rhizome ginger 100 as shown in FIG. 11, and the stem 102, leaves 104 and root 106 extending from the rhizome ginger 100 are generally removed.
When such a rhizome ginger 100 (hereinafter sometimes simply referred to as ginger 100) is used as a condiment or the like, the raw ginger 100 is usually used by grated with a grater or sliced.
However, the raw ginger 100 is hard to slide down because its shape is not constant and is hard. Furthermore, when the raw ginger 100 is slid down, the juice comes out and the fibers also appear. The juice in grated ginger dilutes the taste of seasonings such as soy sauce, and the fiber makes the texture worse.
In addition, normally, at home, one raw ginger 100 cannot be used to the end, and it is stored in a refrigerator or the like. However, the flavor of raw ginger 100 is significantly reduced, causing wilt or mold. In many cases, it must be disposed of.
Therefore, in Patent Document 1 below, in order to obtain a dry ginger that can maintain the flavor of raw ginger, sliced ginger obtained by slicing the raw ginger in a thickness of 2 mm is dried by ventilation at 50 ° C. and 30% relative humidity. It was proposed that ginger whose moisture content became 10% or less after 10 hours from the start of drying was kept at 50 ° C. in a desiccator filled with silica gel and the moisture content became 4% over 10 hours. Has been.

JP 2008-206504 A

According to the above-mentioned Patent Document 1, the obtained dried ginger can be used in the form of powder and exhibits a fresh raw ginger flavor.
Further, even when this powder product was enclosed in a polyethylene bag together with a desiccant and left for 2 months, the ginger flavor could be fully enjoyed.
However, the dried ginger of Patent Document 1 is thinly sliced and very hard, so it cannot be slid down with a grater and is pulverized in a mortar.
On the other hand, at home, it is desired that the necessary amount of dried ginger can be easily slid down with a grater.
Further, the dried ginger of Patent Document 1 is obtained by slicing a raw ginger thinly, then subjecting it to ventilation drying for 10 hours, and further drying with silica gel as a desiccant for 10 hours. Thus, since the manufacturing process of the dry ginger of patent document 1 performs two steps of drying, the manufacturing process is complicated and cannot be adopted as an industrial manufacturing method of dry ginger.
Therefore, the problem of the present invention is that it cannot be slid down with a grater, the problem of the conventional dry ginger and its manufacturing method is complicated and the drying time is long, and it can be slid down with a grater. An object of the present invention is to provide a dry ginger that can be produced industrially and a method for producing the same.

In order to solve the above problems, the present inventors considered that it was advantageous to employ freeze drying as a drying method, and when freeze-dried ginger obtained by rapidly freezing raw ginger was freeze-dried, It was found that the dried ginger obtained was remarkably shrunk and difficult to grind at home.
The present inventors variously examined the freezing conditions of the frozen ginger subjected to freeze drying, and when freezing the raw ginger, the maximum ice crystal formation temperature range in which the internal temperature becomes −1 to −5 ° C. is slowly increased. When freeze-drying was performed on a frozen ginger subjected to slow freezing to pass through, the obtained dried ginger was found to have a small shrinkage rate and could be easily slid down with a grater, and reached the present invention.
That is, the present invention provides a raw rhizome ginger obtained by freeze-drying a frozen ginger obtained by subjecting a raw rhizome ginger to slow freezing by freezing by growing ice crystals in the cells. A dried ginger that maintains its appearance , wherein the dried ginger is a porous dried ginger in which at least some of the cell shapes are preserved . In the present invention, it is preferable that the dried ginger has a porosity of 65 to 85%. The dried ginger is preferably a grated dry ginger.
In addition, the present invention provides a porous shape in which at least some of the cell shapes are preserved so that when the raw rhizome ginger is freeze-dried to obtain a dried ginger, the shape of the raw rhizome ginger can be maintained. In order to obtain a dried ginger of the above, the raw rhizome ginger is subjected to slow freezing by freezing by growing ice crystals in the cells to obtain a frozen ginger, and then freeze-drying the frozen ginger There is a method for producing dried ginger. In the present invention, as the slow freezing, slow freezing in which the passage time of the maximum ice crystal generation temperature zone in which the internal temperature of the rhizome ginger is −1 to −5 ° C. is 5 hours or more can be suitably employed.

In conventional freeze-drying of raw vegetables, after freezing the raw vegetables as fast as possible to prevent the growth of ice crystals in the cells in order to prevent damage to the cells as much as possible, freeze the resulting frozen ginger. It is dry.
However, with freeze-drying of raw rhizome ginger, after freeze-freezing, when freeze-drying the obtained frozen ginger, the resulting dried ginger shrinks significantly due to the destruction of its cells, resulting in raw rhizomes. I can't hold a ginger.
In this respect, in the present invention, a raw rhizome ginger is formed by subjecting the raw rhizome ginger to slow freezing by freezing by growing ice crystals in the cells and then freeze-drying the frozen ginger obtained. It is possible to obtain a porous dry ginger that preserves the shape of raw rhizome ginger while preserving the shape of at least some of the cells.
The dried ginger according to the present invention obtained in this way is porous and the shape of its cell wall is preserved, so that the shape of a raw rhizome ginger can be maintained.
The dried ginger of the present invention can be easily crushed with a grater and powdered, and the aromatic components and pungent components in raw rhizome ginger can be preserved.
By the way, after slowly freezing the raw rhizome ginger, the detailed reason why it is possible to obtain a porous dry ginger that maintains the shape of the raw rhizome ginger is still fully elucidated. It is not considered as follows.
That is, when freeze-drying a frozen ginger obtained by subjecting a fresh rhizome ginger to rapid freezing, when the ice crystals in the cells of the frozen ginger disappear, the cell wall is also dried and contracts. The cell wall contraction force is greater in an undamaged cell wall than in a damaged cell wall, so that the entire cell contracts and the entire ginger also contracts.
On the other hand, in the present invention, a fresh rhizome ginger is subjected to slow freezing in which ice crystals grow in cells and frozen, and then the obtained frozen ginger is freeze-dried.
By such slow freezing, a part of the cell wall of the cell forming the ginger is broken by the ice crystal formed in the cell. For this reason, when ice crystals in cells disappear during freeze-drying, the contraction force of the partially damaged cell wall is weaker than that of the undamaged cell wall, so the overall contraction of the ginger can be reduced, A porous dry ginger that maintains the shape of a raw rhizome ginger can be obtained.

It is a photograph which shows an example of the dry ginger based on this invention. It is a SEM photograph of the dried ginger shown in FIG. It is a graph which shows the result of having measured the hardness of the dry ginger shown in FIG. It is a photograph which shows the grated surface of the dry ginger shown in FIG. It is a chart which shows the result of the gas mass (GSMS) analysis which analyzed the aromatic component in the dry ginger shown in FIG. It is a chart which shows the result of the liquid chromatography analysis (HPLC) which analyzed the pungent component in the dry ginger shown in FIG. It is a photograph which shows the dry ginger obtained by giving freeze-dry to the frozen ginger obtained by quick-freezing the raw rhizome ginger. It is a SEM photograph of the dried ginger shown in FIG. It is a photograph which shows the grated surface of the dry ginger shown in FIG. Dried ginger obtained by freeze-drying a frozen ginger obtained by subjecting a frozen ginger to a slow freezing time in which the internal temperature of the rhizome ginger is -1 to -5 ° C and the maximum ice crystal formation temperature zone is less than 1 hour It is a photograph which shows a grated surface. It is explanatory drawing explaining an example of a ginger. The time-dependent change of the internal temperature of the ginger in the slow freezing performed in Example 1 is shown. The time-dependent change of the internal temperature of the ginger in the slow freezing performed in Example 5 is shown.

An example of the dried ginger according to the present invention is shown in FIG. The dried ginger shown in FIG. 1 is a dried ginger obtained by freeze-drying a rhizome ginger with raw skin.
Such a dried ginger was obtained by subjecting a raw rhizome ginger with skin to slow freezing by freezing by growing ice crystals inside the cells to obtain a frozen ginger and then freeze-drying the frozen ginger. Is.
In order to prevent the cell wall from being destroyed as much as possible, this frozen ginger is obtained by freeze-drying the obtained frozen ginger when using quick freezing that can prevent the growth of ice crystals in the cell as much as possible. In dry ginger, the shrinkage becomes remarkably and hard, and it becomes difficult to grate with a grater. In particular, the fibers in the dried ginger cannot be grated together with other parts, and long fibrous bodies are mixed in the obtained powder, resulting in a decrease in texture.

As the slow freezing employed in the present invention, it is preferable to set the passage time of the maximum ice crystal generation temperature zone in which the internal temperature of the rhizome ginger is −1 to −5 ° C. to 5 hours or more.
Such slow freezing is performed by placing the raw rhizome ginger in a freezer maintained at −20 ° C. in a box formed by a heat insulating material of a predetermined thickness for a predetermined time. Can be applied. In this case, the slow freezing time can be adjusted by adjusting the thickness of the heat insulating material forming the box.
The freeze drying employed in the present invention can be performed under known conditions using a known freeze drying apparatus.

An SEM photograph of the dried ginger obtained as shown in FIG. 1 is shown in FIG. In the SEM photograph shown in FIG. 2, the shape of the cell wall of the ginger is preserved. For this reason, the dried ginger shown in FIG. 1 is porous. Its gas efficiency (measured by Archimedes method) was 60 to 85%.
As shown in FIG. 3, the hardness of the dried ginger shown in FIG. 1 is reduced by 75 to 80% compared to the raw ginger. The ginger hardness shown in FIG. 3 is expressed by pressure input when a pin having a diameter of 2 mm is press-fitted. Such pressure input is measured for the part parallel to the ginger fiber and the part perpendicular to the fiber of the ginger. Has been reduced.
For this reason, when the dried ginger shown in FIG. 1 is grated with a grater, the grated surface is flat as shown in FIG. This indicates that the dried ginger shown in FIG. 1 can simultaneously grind the fibers of the dried ginger and portions other than the fibers, and the obtained ginger powder was uniform.

Moreover, about the aroma component of the dry ginger shown in FIG. 1, the gas mass (GSMS) analysis was conducted together with the aroma component contained in the raw rhizome ginger. The result is shown in FIG. As shown in FIG. 5, the peak positions of the aroma component of the dried ginger and the aroma component of the raw rhizome ginger are the same, and the peak height is also substantially the same. In particular, the amount of the gingibelene component (marked with ● in FIG. 5), which is the main component of the aromatic component of ginger, was present in the same amount as that of raw rhizome ginger. For this reason, even dry ginger exhibits the same fragrance as raw rhizome ginger.
Further, the pungent component of the dried ginger shown in FIG. 1 was also subjected to liquid chromatography analysis (HPLC method) together with the pungent component contained in the raw rhizome ginger. The result is shown in FIG. As shown in FIG. 6, the peak positions of the pungent component of the dried ginger and the pungent component of the raw rhizome ginger are the same, and the peak height is also substantially the same. In particular, the 6-gingeol component, 8-gingeol component, and 10-gingeol component (marked with ● in FIG. 6), which are the main components of the ginger pungent component, are present in the same amount as that of raw rhizome ginger. Was. For this reason, even dry ginger exhibits the same pungent taste as raw rhizome ginger.
The water activity (free water) of the dried ginger shown in FIG. 1 is about 0.2%. For this reason, the dried ginger or ginger powder obtained by grinding the dried ginger can be stored for a long period of time without encapsulating the desiccant in a bag made of a film material. The preserved dried ginger and ginger powder can sufficiently exhibit the pungent taste and fragrance exhibited.
At the time of such storage, a bag made of a gas barrier film material is adopted, and nitrogen is enclosed in the bag, whereby oxidation of the components of the dried ginger and ginger powder can be prevented.
As the gas barrier film material, an aluminum foil, a polyethylene terephthalate film or a nylon film in which aluminum is vapor-deposited on at least one side can be used.

On the other hand, in order to prevent damage to the cells as much as possible, the raw rhizome ginger with skin is subjected to quick freezing to prevent ice crystals from growing inside the cells as much as possible. After obtaining the frozen ginger, the frozen ginger was freeze-dried.
In this quick freezing, raw rhizome ginger is placed in an atmosphere of −20 ° C., and the passage time of the maximum ice crystal generation temperature zone where the internal temperature of the rhizome ginger becomes −1 to −5 ° C. is less than 30 minutes. The ginger was frozen.
The obtained dried ginger was significantly shrunk as shown in FIG. As shown in the SEM photograph shown in FIG. 8, the dried ginger cells are remarkably shrunk and the shape is not preserved at all.
When the dried ginger is slid down with a grater, the fibers protrude from the slashed surface as shown in FIG. This indicates that the dried ginger fiber cannot be slid down simultaneously with other parts. For this reason, the ginger powder obtained was mixed with long fibrous bodies and was uneven.

By the way, as the slow freezing, when the slow freezing in which the passage time of the maximum ice crystal generation temperature zone in which the internal temperature of the rhizome ginger is −1 to −5 ° C. is less than 5 hours is adopted, as shown in FIG. Shrinkage occurs in the dried ginger finally obtained, and fibers protrude from the grated surface of the dried ginger.
However, the degree of shrinkage is light, and the fibrous material is also mixed in the obtained ginger powder, but its length is short, so it is within a satisfactory range.
Moreover, although the dry ginger shown in FIG. 1 was obtained by using raw rhizome ginger with skin, it is needless to say that raw rhizome ginger with the skin removed may be used. By using raw rhizome ginger from which the skin has been removed, it is possible to obtain a dry ginger with a beautiful color appearance. Furthermore, when the dried ginger is slid down, the skin does not scatter and is easily slid down.
In addition, you may perform the removal of a skin after making dry ginger.

A rhizome ginger 100 obtained by removing leaves 104, stems 102, roots 106 and small tuberous rhizomes that are difficult to wash from the ginger shown in FIG. 11 was cut to a size of about 60 g, washed with water, and then washed with sodium hypochlorite water. Sterilized.
After removing water adhering to the sterilized rhizome ginger, the frozen rhizome ginger was slowly frozen to obtain a frozen ginger.
Such slow freezing was performed by placing a box made of a heat insulating material having a predetermined thickness, in which a plurality of raw rhizome ginger was sealed, placed in a freezer maintained at -20 ° C. When the internal temperature of the rhizome ginger was measured, as shown in FIG. 12, the passage time (T) of the maximum ice crystal formation temperature zone in which the internal temperature of the rhizome ginger was −1 to −5 ° C. was 5 hours.
Next, the frozen ginger obtained by subjecting it to slow freezing was supplied to a freeze drying apparatus and subjected to freeze drying.
The obtained dried ginger maintained the shape of the raw rhizome ginger subjected to slow freezing, similar to the dried ginger shown in FIG. The shrinkage rate of the dried ginger was 9.8% with respect to the raw rhizome ginger, and the porosity was 75% as measured by the Archimedes method.
Further, the obtained dried ginger cells had at least a part of the cell shape retained as shown in the SEM photograph (magnification 300 times) shown in FIG.
Furthermore, when the obtained dried ginger was grated using a commercially available grater, it could be easily grated. It can be seen that the grated surface of the dried ginger was a flat surface as shown in FIG. 4 and was able to be grated simultaneously including the fibers. In the ginger powder obtained, almost no fibrous material was found.
When this ginger powder was added to tofu and sown with soy sauce, the ginger aroma and moderate pungent taste did not dilute the soy sauce taste with ginger soup like conventional grated ginger. Together, I was able to eat deliciously. Moreover, when eating tofu, the fiber in the ginger did not reduce the texture.

The ginger powder obtained in Example 1 was sealed together with nitrogen in a bag made of a polyethylene terephthalate film having aluminum deposited on one side. The desiccant was not enclosed in the bag.
The bag filled with the ginger powder was placed in an atmosphere of 70% humidity at 37 ° C. for 3 months, and an accelerated test was performed on the ginger powder sealed in the bag.
When the bag subjected to the acceleration test was opened, the ginger powder that had been encapsulated had the same aroma and pungent taste as when encapsulated in the bag.

In Example 1, except that the rhizome ginger subjected to slow freezing was a rhizome ginger having a peeled or peeled skin, slow freezing and freeze drying were performed in the same manner as in Example 1 to obtain a dried ginger.
The resulting dried ginger had a beautiful creamy appearance. Moreover, the ginger powder obtained by grinding dry ginger was also cream colored.

  The dried ginger skin obtained in Example 1 was removed with a peeler or spoon. The resulting dried ginger had a beautiful creamy appearance. Moreover, the ginger powder obtained by grinding this dry ginger was also cream colored.

Comparative Example 1

In Example 1, instead of slow freezing, the raw rhizome ginger is directly placed in a freezer where the ambient temperature is kept at -20 ° C, and the maximum temperature of the rhizome ginger becomes -1 to -5 ° C. Dried ginger was obtained in the same manner as in Example 1 except that quick freezing with a passage time in the ice crystal generation temperature range of about 30 minutes was adopted. As shown in FIG. 7, the resulting dried ginger has a remarkable shrinkage and a large number of wrinkles as compared with a raw rhizome ginger. The cells, as shown in the SEM photograph of dried ginger shown in FIG. 7 (300 times magnification), are extremely contracted and cannot retain their shape.
Further, when the obtained dried ginger is slid down with a grater, the fibers protrude from the slashed surface as shown in FIG. For this reason, it is difficult to lower dry ginger, and the obtained ginger powder contains long fibrous bodies.
When the obtained ginger powder was added to tofu and sown with soy sauce, the ginger aroma and moderate pungent taste did not dilute the soy sauce taste with ginger soup like conventional ginger grated grated However, the texture was reduced by the fibers in the ginger.

In Example 1, as shown in FIG. 13, the thickness of the heat insulating material of the box body in which a plurality of raw rhizome ginger sealed in a freezer whose atmospheric temperature is kept at −20 ° C. A dried ginger was obtained in the same manner as in Example 1 except that the passage time (T) of the maximum ice crystal formation temperature zone where the internal temperature of the ginger was -1 to -5 ° C was changed to 1 hour.
Although the resulting dried ginger had a cocoon due to shrinkage, it was lighter than the dried ginger obtained in Comparative Example 1 and was within the allowable range.
When the dried ginger is slid down with a grater, the fiber protrudes from the slashed surface as shown in FIG. The protruding length of this fiber was shorter than the dried ginger obtained in Comparative Example 1, and the fibrous material mixed in the obtained ginger powder was within the allowable range.

100 Rhizome ginger 102 Stem 104 Leaf 106 Root T Passing time of maximum ice crystal generation temperature zone

Claims (5)

Dried ginger that maintains the appearance of the raw rhizome ginger obtained by freeze-drying a frozen ginger obtained by subjecting a raw rhizome ginger to slow freezing by freezing by growing ice crystals inside the cells. Because
The dried ginger characterized in that the dried ginger is a porous dried ginger in which the shape of at least some of the cells is preserved .   The dried ginger according to claim 1, wherein the porosity of the dried ginger is 65 to 85%.   The dried ginger according to claim 1 or 2, wherein the dried ginger is a grated dry ginger. When freezing dry raw rhizome ginger to obtain dry ginger,
In order to obtain a porous dry ginger in which at least a part of the cell shape is preserved so that the shape of the raw rhizome ginger can be maintained, ice crystals are grown in the raw rhizome ginger. After obtaining a frozen ginger by applying a slow freezing to freeze,
A method for producing a dried ginger, comprising freeze-drying the frozen ginger.   5. The method for producing a dried ginger according to claim 4, wherein the slow freezing employs slow freezing in which the passage time of the maximum ice crystal generation temperature zone in which the internal temperature of the rhizome ginger is -1 to -5 [deg.] C. is 5 hours or more.