JP2002078466A - Method for producing and storing ripened chestnut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing and storing ripened chestnuts improving deliciousness thereof by ripening during storing. SOLUTION: This method for producing and storing ripened chestnuts comprises ripening the bodies of breathing chestnuts 2 through storing them at <=0 deg.C without freezing them and putting preferably an air-impermeable cover thereon; wherein the cover is put thereon after the chestnuts are stored for at least one day at a predetermined temperature of <=0 deg.C and the temperature thereof becomes <=1 deg.C, the temperature is gradually decreased from 0 deg.C to a target temperature of -X deg.C for at least X days, and the chestnuts at <=-2 deg.C are stored for >=10 days to be ripened, and in order to raise the temperature of the chestnuts at <=0 deg.C stored without frozen to a normal temperature, the temperature is made <0 deg.C for 1 to 2 days, >=0 deg.C but <5 deg.C for further 1-2 day(s), and then a normal temperature of >=5 deg.C for further 1-2 day(s).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing and storing an aged chestnut particularly suitable for sweet chestnuts.

[0002]

2. Description of the Related Art Chestnuts are harvested for a limited time. In order to supply delicious sweet chestnuts to consumers, the chestnuts must be stored without deterioration until the consumption time. Therefore, chestnuts are conventionally kept at a temperature lower than room temperature, so-called refrigerated storage, to maintain freshness.

[0003]

However, in the past, the main focus was on storing the chestnuts so that the freshness and taste of the harvested chestnuts could be maintained as they were, and the chestnuts were aged during storage to improve the taste. That was not taken into account. In view of the current distribution of fresh foods, chestnuts and other agricultural products are forced to be shipped early before they are fully ripe, and the ripe agricultural products that have become the original seasonal taste are favored by consumers in a favorable condition. There is a problem that has not reached. In such a case, if the chestnuts can be aged during storage and their taste can be improved, it is possible to supply delicious sweet chestnuts to consumers year-round.

Accordingly, it is an object of the present invention to provide a method for improving the taste of chestnuts by aging them during storage.

[0005]

According to the first aspect of the present invention, a chestnut living body is breathing,
There is provided a method for producing and storing aged chestnuts, which is characterized by aging by storing at a temperature of 0 ° C. or lower without freezing. In the method according to the first aspect, as described in the second aspect, the chestnuts may be stored in a refrigerator with a non-breathable cover. In this case, it is preferable that the storage is performed at a set temperature of 0 ° C. or less for one day or more, and the cover is put on when the product temperature is 1 ° C. or less. Further, as described in claim 4, it is preferable to gradually decrease the product temperature over X days or more until the product temperature becomes from 0 ° C. to the target temperature −X ° C. Further, as described in claim 5, it is preferable to store at a product temperature of −2 ° C. or less for 10 days or more.

Further, when raising chestnuts stored without freezing at a temperature of 0 ° C. or less to room temperature, the temperature of the chestnuts is reduced to a temperature lower than 0 ° C. over 1 day or more and 2 days or less. It is preferable that the temperature is raised from 0 ° C. to less than 5 ° C. over 1 day to 2 days, and the temperature is raised from 5 ° C. to normal temperature over 1 day to 2 days.

[0007]

Embodiments of the present invention will be described below. First, examples of chestnut varieties that are aged in the present invention include, for example, small chestnuts especially suitable for sweet chestnuts, which are produced in China. Chestnuts aged according to the present invention are suitably used, for example, for sweet chestnuts that are known under the name of Tianjin sweet chestnut in the general market.

[0008] In the present invention, the living body of chestnut 2 that is breathing that has not yet died biologically is transported into, for example, a refrigerator and stored in the refrigerator at a temperature of 0 ° C or less without freezing. I do. In this case, it is preferable that the chestnut 2 be kept at a predetermined target temperature (a target temperature of −2 ° C. or lower, for example, about −4.5 ° C.) in the refrigerator without freezing. For example, as shown in FIG. 1, a plurality of chestnuts 2 are filled together in a hemp bag 1 or the like. Then, as shown in FIG. 2, the hemp bags 1 containing the chestnuts 2 can be stored in an appropriate number in the refrigerator.

Before the chestnut 2 is stored in the refrigerator, the chestnut 2 is usually kept at room temperature, so the temperature of the chestnut 2 is about room temperature. When the chestnut 2 at about room temperature is rapidly cooled to a target temperature (for example, about -4.5 ° C.) in the refrigerator, the chestnut 2 may be frozen or the quality of the chestnut 2 may be deteriorated. Therefore, when the chestnut 2 is carried into the refrigerator and cooled to the target temperature, it is preferable to gradually lower the product temperature over a period of X days or more from 0 ° C. to the target temperature−X ° C. In this case, for example, the target temperature of the chestnut 2 stored without freezing in the refrigerator is -4.5 ° C (X
= 4.5), it is preferable to gradually lower the temperature of the chestnut 2 over 4.5 days or more. Then, freezing and quality deterioration of the chestnut 2 can be prevented. Also, for example, in a refrigerator at a temperature of -2 ° C or less,
It is good to store.

[0010] Thus, for example, chestnut 2 in a refrigerator
If the living body is stored without freezing at a temperature of 0 ° C. or less, cold stress occurs in the living cells of chestnut 2 in the temperature range immediately before freezing, and the sweetness and umami components are hydrolyzed due to the cold stress. Generated. When chestnut 2 is stored at a temperature of −2 ° C. or less for 10 days or more, chestnut 2 changes from an unripe state to a ripe state (a state like a ripe fruit on a tree),
Even if chestnut 2 is harvested before it is fully ripe, it will have an aged taste during storage. The temperature at which chestnut 2 is stored must be below 0 ° C., but must be within a temperature range in which chestnut 2 can be kept alive without freezing. When chestnut 2 is frozen, the structure of chestnut 2 is destroyed, the quality is degraded, and the generation of umami components due to aging does not occur. On the other hand, if the storage temperature exceeds 0 ° C., bacteria will grow and oxidize, and the chestnut will be discolored and putrefaction.

As described above, a plurality of hemp bags (hemp bags containing chestnuts 2) 1 stacked in a refrigerator as shown in FIG.
It is preferable to store the chestnut 2 with a non-breathable cover 3 made of, for example, vinyl, as shown in FIG. In this case, bring chestnut 2 into the refrigerator as described above,
When gradually lowering the temperature of the refrigerator over 0 days from 0 ° C to the target temperature -X ° C over X days, store the refrigerator at a set temperature of 0 ° C or lower for at least 1 day. It is better to cover 3 when the product temperature is 1 ° C. or less. If the cover 3 is covered in this manner, the chestnut 2 contained in the hemp bag 1 or the like can be stored in the refrigerator while appropriately preventing drying, and can be aged. When chestnuts 2 are stored in the refrigerator as described above, the chestnuts 2 are dried and the excess water is released, thereby improving the taste and preventing the deterioration by drying. However, if the chestnuts 2 are too dry, ,
The enzyme is not activated, and the ripening of chestnut 2 becomes difficult to progress. If the chestnuts 2 are stored with a cover 3 made of vinyl or the like, the chestnuts 2 can be prevented from being over-dried.

When the chestnut 2 aged by storing it at a temperature of 0 ° C. or less without freezing as described above is raised to room temperature, the chestnut 2 is kept at −1 ° C. or more and less than 0 ° C. Temperature for 1 day or more and 2 days or less.
The temperature is raised over 1 day to 2 days until the temperature falls below 5 ° C., and the temperature is raised over 1 day to 2 days until the product temperature reaches 5 ° C. or more. Thus, if the temperature is raised slowly, the chestnut 2 can be matured even during the temperature rise, and the temperature of the chestnut 2 is slowly raised from a temperature of 0 ° C. or less to room temperature. Thus, dew condensation can be prevented.

[0013]

Next, an embodiment of the present invention will be described. Product temperature +1
Chinese chestnuts stored at 3.5 ° C were pre-cooled for 2 days in a storage set at ± 0 ° C, and were covered when the product temperature (chestnut temperature) reached + 0.5 ° C. Next, it was stored for 4 days in a storage at a setting of -2 ° C, with the product temperature being approximately -1.5 ° C for 2 days. Then, set the refrigerator temperature for 4 days-
The temperature was lowered to 4.5 ° C. Chestnut temperature from 0 ° C to -4.5
It took about 11 days to reach ℃. FIG. 3 shows the relationship between the temperature of the chestnut and the number of days when the temperature of the chestnut was lowered from room temperature to −4.5 ° C. Then, the chestnuts were aged by storing for 21 days counted from the time when the product temperature became −2 ° C. or less. When the temperature rises,
Store at the set temperature of -1 ° C for 1 day, raise the product temperature to below 0 ° C, further store at the set temperature of + 5 ° C for 1 day, and set the product temperature to 0 ° C.
The temperature was raised to a range of less than 5 ° C. Thereafter, the cover was removed and the temperature was raised to normal temperature (+ 9 ° C.). The chestnuts of this example completed ripening on the 35th day from the date of receipt. As a comparative example, chestnuts were stored for 35 days in a storage set at + 1 ° C.

As a result, the chestnut of the embodiment of the present invention (product temperature-2)
(Storage at 21 ° C. for 21 days) improved the sugar content by 22.2%. On the other hand, the sugar content of the chestnut of the comparative example (stored at + 1 ° C. for 21 days) was improved by 20.3%. The chestnut of the example of the present invention had about 10% improvement in sugar content as compared with the comparative example. FIG. 4 shows a comparison of the free total sugar amount (g of free total sugar in 100 g of chestnut) of the chestnut of the example of the present invention and the chestnut of the comparative example. The sugar amount was 2.68 g / 100 g, and the free total sugar amount of chestnut of the comparative example was 2.32 g / 100 g.

[0015]

According to the first to sixth aspects, chestnuts can be stored while maintaining freshness. In addition, the chestnuts can be aged while being stored, so that the taste can be improved and the seasonal taste can be improved. For this reason, even if the chestnuts are harvested before being ripe, it is possible to obtain ripe chestnuts that have the original seasonal taste.
Delicious sweet chestnuts can be supplied to consumers year round.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hemp bag filled with chestnuts.

FIG. 2 is an explanatory view showing a state in which a cover is applied to stacked hemp bags.

[FIG. 3] In the embodiment of the present invention, the temperature of chestnut is reduced from room temperature
It is a graph which shows the relationship between article temperature and days when it falls to 4.5 degreeC.

FIG. 4 is a graph comparing the amount of free total sugar in the chestnut of the example of the present invention and the chestnut of the comparative example.

[Explanation of symbols]

 1 hemp bag 2 chestnut 3 cover

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshimasa Sugii 3-1-4, Hamacho, Funabashi-shi, Chiba F-term (reference) 4B036 LC01 LF19 LH29 LP17

Claims (6)

[Claims] 1. A method for producing and storing an aged chestnut, which comprises aging a living chestnut that is breathing at a temperature of 0 ° C. or lower without freezing. 2. The method for producing and storing mature chestnuts according to claim 1, wherein the chestnuts are stored in a refrigerator with a non-breathable cover. 3. Storage at a set temperature of 0 ° C. or less for one day or more,
3. The method for producing and storing aged chestnut according to claim 2, wherein said cover is applied when the product temperature is 1 ° C. or less. 4. The method according to claim 1, wherein the temperature is gradually reduced over a period of X days or more until the temperature of the product becomes from 0 ° C. to the target temperature −X ° C. Manufacturing and storage of aged chestnuts. 5. The method for producing and storing an aged chestnut according to claim 1, wherein the chestnut is stored at a temperature of −2 ° C. or less for 10 days or more. 6. When raising chestnuts stored without freezing at a temperature of 0 ° C. or less to room temperature, the temperature of the chestnuts is reduced to less than 0 ° C. over 1 day to 2 days, and then 1 day to 2 days. The method according to claim 1, wherein the temperature of the product is set to a range of 0 ° C. to less than 5 ° C. over a period of 1 day to 2 days. 3. A method of producing and storing an aged chestnut of any of 3, 4 or 5.