JP2516149B2 - Manufacturing method of cooked greens that can be supplied throughout the year - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to a cooking method in which a raw chestnut with a skin is refrigerated for a certain period of time to increase its sweetness, then transferred to a frozen / frozen storage, taken out at an arbitrary time and cooked by pressurization and heat. The present invention relates to a method for producing green.

[0002]

2. Description of the Related Art Conventionally, as a method for storing chestnuts while keeping moisture, (1) they are buried in moist sand. (2) Pack in a thin plastic bag and keep it in the refrigerator while keeping the humidity. (3) Put in a refrigerator equipped with a humidifier. (4)
There has been a method in which the peeled chestnut is immersed in an alum solution, steamed and frozen, further immersed in an ascorbic acid solution, and then frozen and stored. However, (1), (2),
In the method of (3), due to germination, spoilage, etc. during storage, a considerable amount became unsuitable for food, and there was a limit to the shelf life. In addition, chestnuts stored for a long time in this way are
When cooked, the skin was darkened and the appearance deteriorated, the flesh inside turned brown, the color tone was poor, the appetite was poor, and the flavor, sweetness and texture of the tongue were poor.

Further, in the method (4), the demon skin and astringent skin (hereinafter referred to as skin) are removed, so that the peculiar shape, color and the like of the chestnut with skin are lost. Also, because the skin is removed, the pulp easily collapses during steaming,
It becomes necessary to use additives such as miyobaban. Further, the pulp and air are easily brought into contact with each other, and discoloration due to the oxidation of polyphenols and the like in the pulp is likely to occur, but it is necessary to use an antioxidant such as ascorbic acid in order to prevent this.

On the other hand, regarding the sweetness of chestnuts, the present inventor saccharified the starch in proportion to the refrigeration period until the 40th day after refrigeration, and mainly increased the sucrose content. Although it has already been clarified that it becomes about 3 times and becomes very sweet, it is difficult to maintain the maximum sweetness for a long period of time because it also decreases due to the subsequent refrigeration.

[0005]

DISCLOSURE OF THE INVENTION The present inventor eliminates such drawbacks and increases the sugar content by refrigerating for a certain period of time. Studies were conducted in order to obtain cooked greens that can be stored for a certain period of time and used as an edible product without damaging the flavor, texture and appearance without using any external additives.

[0006]

[Means for Solving the Problems] As a result, the chestnuts with skin after harvest are refrigerated at a temperature of -2 ° C to 5 ° C for 30 to 50 days, and when the sweetness reaches the maximum, the raw chestnuts are raw. Leave-
It is frozen at a temperature of 25 ° C or lower, transferred to a frozen storage, taken out at an arbitrary time, transferred into a pressure cooker while frozen, and under a pressure of about 2 kg / cm ² (including atmospheric pressure) (atmosphere inside the container). The temperature is about 120 ° C.) and wet cooking is performed. The cooking time is 10 to 20 minutes after reaching a predetermined pressure (temperature).
By doing so, it was possible to complete the invention by finding out that it would be a cooking paste suitable for the purpose.

[0007]

In the present invention, raw chestnuts with skin are refrigerated for a certain period of time to increase the sugar content, and when the maximum sweetness is reached, the chestnuts are frozen and transferred to frozen storage to remove starch contained in pulp. Since the enzymes involved in saccharification are inactivated, it is possible to prevent the decrease in sugar content that would occur when refrigerated subsequently, and it is possible to perform long-term storage while maintaining the highest sweetness. Since it is frozen storage, it is possible to prevent the loss due to germination, spoilage, etc., which is generated in a considerable amount in refrigeration for a long time, and it is possible to practically eliminate the limit of the storable period. Further, deterioration of quality such as darkening of skin after cooking, browning of flesh, deterioration of flavor, etc., which is seen in chestnuts refrigerated for a long period of time, is significantly reduced.

On the other hand, frozen chestnuts stored frozen and frozen are cooked under normal pressure in the same manner as normal raw chestnuts, because the effects of ice crystals and the like generated in the pulp during freezing remain, resulting in the pulp. The grain size becomes coarse and the texture of the tongue becomes bad, leading to deterioration of the taste. However, when the food is heated under heat and pressure, the texture does not deteriorate and the texture becomes smooth and the taste becomes good. In addition, in the case of applying pressure and humidity heat, since the heating time of chestnuts can be shortened, deterioration of flavor due to long-term exposure to high temperature or generation of off-taste such as acridness is eliminated. Furthermore, because it is cooked under pressure,
The sterilization effect is high, the days after cooking are good, and the shelf life is longer than that of cooking under normal pressure.

[0009]

Embodiments of the present invention will be described below.

(Experimental Example 1) A chestnut (variety: "Ginyori") immediately after harvest was put in a polyethylene bag having a thickness of 0.03 mm and sealed with the skin at room temperature (16 ° C to 22 ° C) (room temperature group). , 0 ° C (0 ° C section), -2
The sample was placed at each temperature of ° C (-2 ° C section) for various periods, and the sugar content of each period elapsed was measured by instrumental analysis and compared. The results are shown in Table 1. As is clear from the results, the sugar content of chestnuts hardly increased without refrigeration, the sugar content reached the maximum in 30 to 60 days at 0 ° C, and decreased again after 60 days. .

[0011]

[Table 1]

(Experimental Example 2) Chestnuts (variety: "Kunimi" and "Tsukuba") immediately after harvest were placed at 0 ° C for different periods as in the experimental example 1 at 0 ° C, and after each period, All of them were transferred to -25 ° C and frozen, and the sugar contents of those that had been kept at the same temperature for 8 months or longer were measured by instrumental analysis and compared. The results are shown in Table 2. As is clear from the results, there are some differences in the period until the maximum sugar content is reached depending on the variety,
Even if the freezing period after refrigeration is as long as 8 months, it will be 0 after the harvest.
The one having a period of refrigeration at 28 ° C for 28 days to 42 days has the highest sugar content, and the sugar content achieved during the refrigeration treatment is retained.

[0013]

[Table 2]

(Experimental Example 3) 4 varieties of chestnuts (“Ginyoro”, “Tanzawa”, “Kunimi”, “Tsukuba”) immediately after harvesting were -25 immediately without refrigeration.
What was frozen and frozen at ℃, steamed under pressure at 120 ℃ for 10 minutes (non-refrigerated area) and after refrigerated at 0 ℃ for 42 days, frozen and frozen as in the uncooled area, and steamed in the same way. The sensory evaluation was carried out by 26 panelists divided into different groups (invention group) and compared. In addition, for each of the plots, a sample immediately before steaming was used to perform a sugar content analysis by a device and a measurement with a refractometer, and the results were compared. The results are shown in Table 3. As is clear from the results, the sugar content of the present invention section was 2.4 to 3.2 times higher than that of the non-refrigerated section, and all sensory evaluations were excellent in all the varieties.

[0015]

[Table 3]

(Experimental Example 4) Chestnuts (variety: "Ginyoro") immediately after harvest were refrigerated at 0 ° C for 7 months, steamed under normal pressure at 100 ° C for 40 minutes (refrigerated section) and at 0 ° C for 30 months. After refrigerating for a day, the product was transferred to -25 ° C, frozen, and stored frozen at the same temperature for 6 months under pressure.
The colors (brightness) of the demon skin surface and the pulp cross section of the one steamed at 0 ° C. for 10 minutes (invention group) were compared. Table 4 shows the results.
It is as follows. As is clear from the results, in the present invention group, both the skin and the flesh have greater color brightness than the refrigerated section, and no darkening or browning occurs.

[0007]

[Table 4]

(Experimental Example 5) Chestnuts frozen at 25 ° C. in a raw state were steamed at 100 ° C. under atmospheric pressure (atmosphere temperature in the kettle) for 40 minutes (cooking section under atmospheric pressure for 40 minutes) and 120 ° C. under pressure (kettle). A thermocouple element was inserted into each chestnut seed center of the one steamed for 10 minutes (inside atmosphere temperature) (invention group), the temperature was measured, and the time elapsed at 100 ° C. or higher was compared. The results are shown in Table 5. As is clear from the results, in the plot of the present invention, the time at which the temperature of the seed and seed core of the chestnut is 100 ° C. or higher is shortened to about 1/3 of that in the cooking plot at a normal pressure of 40 minutes.

[0019]

[Table 5]

(Experimental Example 6) Chestnuts (variety: "Ginyoro") immediately after harvest were refrigerated at 0 ° C for 30 days and then cooked at 100 ° C under atmospheric pressure for 40 minutes without freezing (freezing and atmospheric pressure). (Cooking area), freeze-free at 100 ° C under atmospheric pressure
3 of those cooked at 40 ° C for 40 minutes (frozen atmospheric pressure cooking zone), those that were refrigerated and frozen similarly to the frozen atmospheric pressure cooking zone, and then cooked at 120 ° C for 10 minutes under pressure (invention zone)
Sensory evaluation was performed on the types by 10 panelists. The results are shown in Table 6. As is clear from the results, the organoleptic evaluation of the present invention section is superior to the frozen normal pressure cooking section in all items, almost the same as the non-freezing normal pressure cooking section, and there is no adverse effect on the taste by freezing. Excluded.

[0021]

[Table 6]

(Example 1) To increase the sugar content of raw chestnuts with skin after harvest and to achieve the maximum sweetness, low temperature treatment was performed for a certain period in a refrigerator. If the temperature of the refrigerator is between −2 ° C. and + 5 ° C., the sweetness increases due to the conversion of starch into sugar. The closer the temperature is to 0 ° C., the faster the increase in sweetness. Loss due to rot and germination inside will be reduced. Depending on the variety of chestnuts, the rate of increase in sweetness and the degree of sweetness when the maximum sweetness is reached will differ slightly, but usually the maximum sweetness is obtained by treatment at 0 ° C for 30 to 50 days. , Freeze at this point and transfer to frozen storage.
Put it in a plastic bag to prevent it from drying during refrigeration and seal it, or use a humidifier. During frozen storage, it is also sealed in a plastic bag to prevent it from drying.

A required amount of the chestnuts thus frozen and stored is taken out, and, while frozen, using a pressure cooker such as a pressure cooker under a pressure of about 2 kg / cm ² (including atmospheric pressure) (atmosphere in the vessel). Wet heat cooking at a temperature of about 120 ° C. The cooking time is 10 to 20 minutes after reaching a predetermined pressure (temperature). Turn off the fire immediately after the cooking time has passed, and gradually reduce the pressure and temperature in the pressure cooker to prevent the chestnut from bursting due to the pressure difference between the inside and outside of the chestnut seed due to rapid depressurization. .

[0024]

EFFECTS OF THE INVENTION According to the present invention, the original sweetness of chestnuts can be increased about 3 times without damaging the chestnuts with skin and without using any external preservatives or sweeteners. Loss due to germination, spoilage, etc. during storage can be minimized, and cooked greens excellent in appearance, taste and shelf life after cooking can be appropriately produced and supplied throughout the year.

Claims (1)

(57) [Claims] 1. A method of cooking, characterized in that a raw chestnut with a skin is refrigerated for a certain period of time to increase its sweetness, then transferred to a freezing / frozen storage, taken out at an arbitrary time and cooked under pressure and heat. Manufacturing method of green.