JP2009213431A - Method for preventing decolorization of green color of green citrus fruit - Google Patents

Abstract

【Task】
To prevent the greening of green citrus fruits such as green citrus citrus fruits and to enable long-term maintenance of the commercial value of green citrus fruits that emphasize the skin color.
[Solution]
A method for preventing green citrus from de-greening, wherein white LED light is continuously irradiated during a refrigerated storage period in a low temperature region where the green citrus does not cause a low temperature failure. The low temperature region may be 3 to 8 ° C., and the illuminance of continuous irradiation of the white LED light may be 100 to 300 Lux.
[Selection] Figure 3

Description

  The present invention relates to a method for preventing green citrus fruits from de-greening, which prevents the de-greening of green citrus fruits such as green citrus citrus fruits and enables long-term maintenance of the commercial value of green citrus fruits that emphasizes the skin color.

  Conventionally, in Patent Document 1, in order to maintain the high freshness of so-called leafy vegetables, temperature control in a low temperature region including an unfrozen temperature zone of food at 10 ° C. to 0 ° C. or less and LED irradiation are performed in combination. A method of irradiating a red LED or a blue LED as LED irradiation is proposed. And, it is said that the light intensity of LED irradiation is preferably about 0.1 mcd to 10,000 mcd. And since it is a leafy vegetable, the experiment is performed in a period of 9 days or less.

  In addition, Non-Patent Document 1 discloses a point where an attempt was made to use red LED weak light irradiation and nutrient solution gel for storing weak light irradiation CA (Control LED Atmosphere) of a green plant. And as a green plant body, the point which used the chervil (form like a carrot leaf) and tomato grafting cell molding seedling which the quality degradation after a harvest is remarkably quick among raw edible herbs is described. Furthermore, although research is also underway on mixed irradiation of red and blue light, it is said that when blue light is mixed, the light compensation point (the light intensity at which the photosynthesis rate becomes 0) decreases.

Further, Patent Document 2 discloses that in a cool box intended for low-temperature storage of green leafy vegetables, weak light irradiation is performed using a white fluorescent lamp when the inside of the box is sealed. In this case, when stored at a low temperature of 1 ° C. to 10 ° C. under low light irradiation with a photosynthetic effective photon flux density (PPFD) of 1 μmol · m ⁻² · s ^{−1 to} 10 μmol · m ⁻² · s ⁻¹ , green leafy vegetables The reduction in chlorophyll concentration of the Japanese radish can be reduced, and the quality of green leafy vegetables can be maintained. The experiment takes 17 days.

In addition, by irradiating far-infrared rays to the sudachi fruit under precautions and heating the sudachi pericarp moderately, it suppresses the increase in respiratory rate that appears to be caused by abnormalities in respiratory metabolism due to low temperatures during subsequent storage Patent Document 3 describes a method for maintaining the freshness of sudachi that is intended to suppress the occurrence of skin damage. Then, it is desirable to perform far-infrared treatment under conditions where the heater temperature is 500 ° C., the distance from the heater to Sudachi is 38 cm, the far-infrared treatment time is 12 minutes, and the fruit surface is 50 ° C.
JP 2001-61459 A “Biological control”, Vol. 42, no. 4, pp. 353-356, 2004 JP-A-9-28363 JP-A-6-90659

As described above, conventionally, green leafy vegetables have only been kept fresh for about half a month. And as for the de-greening prevention of green citrus fruits, as shown in the said patent document 3, the skin of a sudachi is heated to 50 degreeC, and when it considers the quality of green citrus fruits, it cannot be said to be enough.
On the other hand, Yamaguchi Prefecture's special products, green perfume citrus and Nagato Yuzukichi, belong to the citrus family, and are harvested from mid-August earlier than Sudachi and Kabos, and the juice is used as ponzu, vinegar miso and dressing . Nagato Yukikichi is expected to have a commercial value as a seasoning for the year-end and New Year holidays, but when stored for a long period of time, the skin color will change from green to yellow. There was a problem that green retention) could not be maintained, and development of a method for preventing degreening was expected.

  Therefore, the object of the present invention is to remove the peel from the conventional method, for example, when it is stored at a temperature of 0 to 10 ° C., where storage for 1 to 2 months was the limit for preventing degreening. It is to provide a greening prevention method capable of preventing greening, and a cold storage for preventing greening, to prevent green citrus fruits that emphasize the skin color, and to enable long-term maintenance of commercial value.

  In order to achieve this object, the present invention is configured as follows.

The invention according to claim 1 is a method for preventing green citrus from de-greening, and continuously irradiating white LED light during a refrigerated storage period in a low temperature region where the green citrus does not cause a low temperature failure. This is a method for preventing the greening of green citrus fruits.
The invention according to claim 2 is characterized in that the low temperature region is 3 to 8 ° C., and the illuminance of continuous irradiation of light from the white LED is 100 to 300 Lux. It is a green prevention method.
The invention according to claim 3 is the green citrus according to claim 1 or 2, wherein the continuous irradiation of the light of the white LED is applied to the entire surface of the green citrus during refrigerated storage. This is a method of preventing degreening.
The invention according to claim 4 is the green citrus de-greening prevention method according to any one of claims 1 to 3, wherein the white LED is a blue excitation white LED.
Furthermore, the invention which concerns on Claim 5 is a cool box which implements the degreening prevention method of any one of Claim 1 thru | or 4, Comprising: The said cool box which can control temperature, and the said cool box And a white LED irradiating device capable of continuously irradiating the light of the white LED installed at an appropriate position.

  Green citrus fruits that emphasize the skin color can be prevented from degreening, and in the conventional technology, products that can be stored for 2 months in order to prevent degreening in order to keep the product value can be prevented from being degreened for 3 months or longer. Long-term storage of value became possible. In addition, since a white LED is used in the present invention, it is easy to handle when irradiating light on the entire surface of the green citrus as compared with the use of a white fluorescent lamp, and also contributes to energy saving with less temperature rise. .

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Nagato Yukikichi, after pre-drying (in order to suppress the respiration of the skin before transporting and storing the fruit, take measures to dry the skin a little in advance), during storage at 3-8 ℃, blue excited white LED Is stored while irradiating the light at an illuminance of 100 to 300 Lux (corresponding to weak light).
In addition, LED means a light emitting diode.
In addition, the white LED used in the embodiment of the present invention is light that is centered around 0.3 on both the X and Y axes in the color coordinates of the JIS Z8701 XYZ color system, and approximates so-called sunlight. It is a general term for light emitting devices.

After harvesting Nagato Yuzukichi, the pre-drying measures were taken, and each 200g (about 4 fruits) was packed into a low-density polyethylene bag, and the entrance was folded (unsealed). Stored in a refrigerator. Nagato Yukikichi was packed in a low-density polyethylene bag and sealed in an unsealed state. The inside of the bag was adjusted to an appropriate concentration of environmental gases (oxygen and carbon dioxide) to suppress the breathing of the fruit, and water transpiration from the fruit was further suppressed. It is to do.

  Blue excited white LEDs are laid on the peripheral surface of the cool box and all the shelves, and the blue excited white LEDs are irradiated on the entire surface of all Nagato Yukitsuki during storage.

  In addition, when providing blue excitation white LED in a shelf, what was installed in transparent shelf boards, such as an acrylic board, is used. The shelf plate may be a reflecting plate capable of transmitting light. Moreover, it can also be set as the form which inserts the net-like body by which blue excitation white LED was laid between the Nagato Yukikichi packed in a bag. Furthermore, you may connect white LED in a string shape and arrange | position this between Nagato Yukikichi during storage.

  Also, Nagato Yukikichi is stored on a conveyor that circulates in a horizontal plane, and the blue excitation white LED light is irradiated to the entire surface of all Nagato Yuzukichi during storage by irradiating the light of the blue excitation white LED from the upper and lower surfaces. You may be made to do.

  In FIG. 2, for each of August and September harvested Nagato Yukitsuki, only the temperature control at 4 ° C. and the light of the blue excitation white LED (illuminance 217 Lux) continued to be irradiated during the temperature control at 4 ° C. The change in skin color was shown in comparison. In each month, the left two rows are fruits with only temperature control at 4 ° C., and the right two rows are fruits that have been continuously irradiated with light from a blue excited white LED during temperature control at 4 ° C. For Nagato Yuzukitchi harvested in August, the comparison is after 36 days, 63 days and 91 days from storage. For Nagato Yuzukitchi harvested in September, the comparison is after 28 days, 63 days and 84 days from storage.

  As is clear from FIG. 2, Nagato Yuzuchi of August harvest and September harvest are both 63 days after storage, that is, after about 2 months, the skin color changes from green to yellow if it is simply refrigerated. Have begun to do. However, the green color of the pericarp is maintained when the light of the blue excitation white LED is continuously irradiated at the same time as refrigerated storage. Furthermore, at the time when about 1 month passed, the skin color completely changed from green to yellow in the case of refrigerated storage. However, in the case where the light of the blue excitation white LED is continuously irradiated at the same time as refrigerated storage, the green color of the skin is still maintained.

  The degree of change in skin color seen in FIG. 2 is shown as a graph in FIG. In FIG. 3, the relationship between the number of storage days and the surface color is shown on the left side for Nagato Yuzukichi harvested in August and on the right side for Nagato Yuzukichi harvested in September. The surface color on the vertical axis is indicated by a hue angle, and a change in the surface color corresponding to the storage days on the horizontal axis can be seen. The hue angle of 180 ° is blue-green and 90 ° is yellow, and the hue angle of the green fruit on the harvest day is 125 to 130 °.

In the graph of FIG. 3, the ◆ mark (Control) is stored only by temperature control at 4 ° C., and the ■ mark (LED) is the temperature control at 4 ° C. and the light of the blue excitation white LED is illuminance average 217 Lux It is preserved while irradiating continuously. The photosynthesis effective photon flux density (PPFD) at this time is 3.24 μmol · m ⁻² · s ⁻¹ .

  As can be seen from the graph of FIG. 3, in the case of Nagato Yuzuki harvested in August, the hue angle of the surface having a hue angle of about 130 ° begins to decrease with the passage of storage days. Until 30 days (one month) have passed, the surface color between the one that was stored only by temperature control at 4 ° C. and the one that was irradiated with the light of the blue excitation white LED simultaneously with the temperature control at 4 ° C. There is no difference. However, after that, the difference in surface color becomes clear between them. Further, the surface color having commercial value is about 115 ° or more, and when it is stored only by temperature control of 4 ° C., about 60 days have passed. After 60 days, the pericarp quickly turns yellow. On the other hand, when the light of the blue excitation white LED is continuously irradiated at the same time as the temperature control at 4 ° C., the green color with commercial value is maintained until about 90 days (3 months).

  Furthermore, when looking at Nagato Yuzukichi harvested in September, the maturity of the day of harvest progressed compared to that of August harvest, and when stored with only temperature control at 4 ° C, the yellow color of the peel was reached after 60 days. The conversion is slightly more advanced than the August harvest. And then, the pericarp quickly turns yellow. On the other hand, when the light of the blue excitation white LED is continuously irradiated at the same time as the temperature control at 4 ° C., the green color with commercial value is maintained until about 90 days (3 months), as in the case of the August harvest. I'm leaning.

  In the above, although the experimental example was shown with the storage temperature of 4 ° C. and the illumination intensity of the white LED of 217 Lux, the storage temperature may be 3 ° C. to 8 ° C. When the storage temperature is as low as 3 ° C or less, Nagato Yukitsuki suffers from depression and browning, which are low-temperature obstacles, and the commercial value is significantly reduced. Furthermore, the illumination intensity of the white LED may be 100 to 300 Lux (corresponding to weak light).

Incidentally, low temperature damage occurs in tropical and subtropical fruits and vegetables including bananas.
Examples of the green citrus include Nagato Yuzukichi, Sudachi, Kabosu, lime, and extremely early-growth Satsuma mandarin with green color remaining on the skin.

Moreover, you may use near ultraviolet excitation white LED as white LED.
Moreover, continuous irradiation of white LED should just be irradiated substantially continuously, Comprising: There may be time which is not irradiated intermittently in the whole irradiation time.
Further, instead of continuous irradiation of white LED light, intermittent irradiation of white LED light by PWM control may be considered.

It is a figure which shows the state which has preserved Nagato Yuzukitchi in the cool box of this invention. It is a figure which shows the change of the color of the skin of Nagato Yuzukitchi by the difference in storage days. It is a graph which shows the degreening suppression by LED process of the stored Nagato Yuzukitchi fruit.

Claims (5)

  A method for preventing green citrus degreening, wherein the green citrus is continuously irradiated with white LED light during a refrigerated storage period in a low-temperature region where the green citrus does not cause a low-temperature failure. Green prevention method.   2. The method of preventing green citrus degreening according to claim 1, wherein the low temperature region is 3 to 8 [deg.] C., and the illuminance of continuous irradiation of light of the white LED is 100 to 300 Lux.   3. The method of preventing green citrus degreening according to claim 1 or 2, wherein the continuous irradiation of the light of the white LED is applied to the entire surface of the green citrus during refrigerated storage.   The method for preventing green citrus degreening according to any one of claims 1 to 3, wherein the white LED is a blue excitation white LED.   5. A cold box for carrying out the method for preventing degreening according to claim 1, wherein the cold box is capable of temperature control, and a white LED is installed at an appropriate position in the cold box. And a white LED irradiation device capable of continuously irradiating the light.